Science.gov

Sample records for rice husk ash-synthesized

  1. Insulating panels with rice husk

    SciTech Connect

    Salas, J.; Veras, J.

    1986-01-01

    This study includes the quantitative results of tests caried out on 7.5 x 15.0 cm cylindrical test pieces and fullsized panels with a cement and rice husk, produced by using means belonging to the so-called ''appropriate technologies''. These results are summarized and analyzed with a view to providing a possible alternative for substituting other insulating materials, which are generally imported, in developing countries. The technical results presented point towards a promising future for the task undertaken, within the context of a research project on ''materials, technologies and prototypes for very low-cost housing'' which, in a - multinational capacity, is being developed at the Instituto E. Torroja.

  2. Physical and thermochemical properties of rice husk

    SciTech Connect

    Mansaray, K.G.; Ghaly, A.E.

    1997-11-01

    Rice husk a major by-product of the rice milling industry, is one of the most commonly available lignocellulosic materials that can be converted to different types of fuels and chemical feedstocks through a variety of thermochemical conversion processes. Proper understanding of the physical and thermochemical properties of rice husk is necessary for the design of thermochemical conversion systems. This study provides information on moisture content, bulk density, particle size, heating values, proximate analysis, ultimate analysis, ash composition, and ash fusibility characteristics for six rice husk varieties. The moisture content ranged from 8.68 to 10.44%, and the bulk density ranged from 86 to 114 kg/m{sup 3}. The results showed excessive volatile release of over 60%, high ash content ranging from 15.30 to 24.60% (dry weight basis), and high silica content of the ash ranging from 90 to 97%. The lower heating values ranged from 13.24 to 16.20 MJ/kg (dry weight basis). The ash fusion temperatures of all the varieties were found to be over 1,600 C. The differences in varietal characteristics have significant effects on the chemical properties of rice husk.

  3. Recycling rice husks for high-capacity lithium battery anodes

    PubMed Central

    Jung, Dae Soo; Ryou, Myung-Hyun; Sung, Yong Joo; Park, Seung Bin; Choi, Jang Wook

    2013-01-01

    The rice husk is the outer covering of a rice kernel and protects the inner ingredients from external attack by insects and bacteria. To perform this function while ventilating air and moisture, rice plants have developed unique nanoporous silica layers in their husks through years of natural evolution. Despite the massive amount of annual production near 108 tons worldwide, so far rice husks have been recycled only for low-value agricultural items. In an effort to recycle rice husks for high-value applications, we convert the silica to silicon and use it for high-capacity lithium battery anodes. Taking advantage of the interconnected nanoporous structure naturally existing in rice husks, the converted silicon exhibits excellent electrochemical performance as a lithium battery anode, suggesting that rice husks can be a massive resource for use in high-capacity lithium battery negative electrodes. PMID:23836636

  4. Thermal degradation of rice husks in an oxygen atmosphere

    SciTech Connect

    Mansaray, K.G.; Ghaly, A.E.

    1999-06-01

    Of the various energy conversion options of rice husk, thermochemical conversion processes such as pyrolysis, combustion, and gasification offer the most efficient way to use rice husk. However, a knowledge of the thermal characteristics of rice husks is essential for the optimal design of these systems and for ensuring stringent emissions as well as high conversion efficiency. Thermogravimetric analysis is used to profile weight loss due to physical and chemical phenomena taking place in the sample while being subjected to high temperatures. This technique presents an ideal system to study thermal properties of carbonaceous materials. Evaluation of the thermogravimetric behavior of four rice husk varieties (Lemont, ROK 14, CP 4, and Pa Potho) at three heating rates (10, 20, and 50 C/min) in an oxygen atmosphere is described. The thermal degradation rates, the initial degradation temperature, and the residual weight at 700 C were determined. These thermal degradation indices of rice husks are a function of temperature, heating rate, and the composition of the rice husks. The initial degradation temperature decreased while both the thermal degradation rate and the residual weight at 700 C increased when the heating rate was increased. The higher the cellulosic content of the rice husk, the higher the thermal degradation rate and the initial degradation temperature. Also, higher ash content in the rice husk resulted in higher residual weight at 700 C. Rice husk could be degraded to the extent of 73--80%.

  5. [Adsorption mechanism of furfural onto modified rice husk charcoals].

    PubMed

    Deng, Yong; Wang, Xianhua; Li, Yunchao; Shao, Jing'ai; Yang, Haiping; Chen, Hanping

    2015-10-01

    To evaluate the absorptive characteristics of furfural onto biomass charcoals derived from rice husk pyrolysis, we studied the information of the structure and surface chemistry properties of the rice husk charcoals modified by thermal treatment under nitrogen and carbon dioxide flow and adsorption mechanism of furfural. The modified samples are labeled as RH-N2 and RH-CO2. Fresh rice husk charcoal sample (RH-450) and modified samples were characterized by elemental analysis, nitrogen adsorption-desorption isotherms, Fourier-transform infrared spectroscopy and Boehm titration. The results show that fresh rice husk charcoal obtained at 450 degrees C had a large number of organic groups on its surface and poor pore structure. After the modification under nitrogen and carbon dioxide flow, oxygenic organics in rice husk charcoals decompose further, leading to the reduction of acidic functional groups on charcoals surface, and the increase of the pyrone structures of the basic groups. Meanwhile, pore structure was improved significantly and the surface area was increased, especially for the micropores. This resulted in the increase of π-π dispersion between the surfaces of rice husk charcoals and furfural molecular. With making comprehensive consideration of π-π dispersion and pore structure, the best removal efficiency of furfural was obtained by rice husk charcoal modified under carbon dioxide flow.

  6. CFD Analysis of Bubbling Fluidized Bed Using Rice Husk

    NASA Astrophysics Data System (ADS)

    Singh, Ravi Inder; Mohapatra, S. K.; Gangacharyulu, D.

    Rice is Cultivated in all the main regions of world. The worldwide annual rice production could be 666million tons (www.monstersandcritics.com,2008) for year 2008. The annual production of rice husk is 133.2 million tons considering rice husk being 20% of total paddy production. The average annual energy potential is 1.998 *1012 MJ of rice husk considering 15MJ/kg of rice husk. India has vast resource of rice husk; a renewable source of fuel, which if used effectively would reduce the rate of depletion of fossil energy resources. As a result a new thrust on research and development in boilers bases on rice husk is given to commercialize the concept. CFD is the analysis of systems involving fluid flow, heat transfer and associated phenomena such as chemical reactions by means of computer-based simulation. High quality Computational Fluid dynamics (CFD) is an effective engineering tool for Power Engineering Industry. It can determine detailed flow distributions, temperatures, and pollutant concentrations with excellent accuracy, and without excessive effort by the software user. In the other words it is the science of predicting fluid flow, heat and mass transfer, chemical reactions and related phenomena; and an innovate strategy to conform to regulations and yet stay ahead in today's competitive power market. This paper is divided into two parts; in first part review of CFD applied to the various types of boilers based on biomass fuels/alternative fuels is presented. In second part CFD analysis of fluidized bed boilers based on rice husk considering the rice husk based furnace has been discussed. The eulerian multiphase model has used for fluidized bed. Fluidized bed has been modeled using Fluent 6.2 commercial code. The effect of numerical influence of bed superheater tubes has also been discussed.

  7. Soil Incorporation of Silica-Rich Rice Husk Decreases Inorganic Arsenic in Rice Grain.

    PubMed

    Seyfferth, Angelia L; Morris, Andrew H; Gill, Rattandeep; Kearns, Kelli A; Mann, Jessica N; Paukett, Michelle; Leskanic, Corey

    2016-05-18

    Arsenic decreases rice yield, and inorganic grain As threatens human health; thus, strategies to decrease rice As are critically needed. Increased plant-available silica (Si) can decrease rice As, yet the source of Si matters. Rice husk, an underutilized and Si-rich byproduct of rice production that contains less labile C and an order of magnitude less As than rice straw, may be an economically viable Si resource to decrease rice As, yet the impact of rice husk incorporation on As in the rice-soil nexus has not been reported. This proof-of-concept study shows that rice husk incorporation to soil (1% w/w) decreases inorganic grain As by 25-50% without negatively affecting grain Cd, yield, or dissolved CH4 levels. Rice husk is a critical yet perhaps overlooked resource to improve soil quality through enhanced nutrient availability and attenuate human health risks through consumption of As-laden grain.

  8. Thermogravimetric analysis of rice husks in an air atmosphere

    SciTech Connect

    Mansaray, K.G.; Ghaly, A.E.

    1998-08-01

    In rice-producing countries, large amounts of rice husks are generated as waste material for which there is no ready use and in some cases may have a negative value because of the cost of disposal. Most of these countries depend on fossil fuels for their energy uses, and rice husk can be used to supplement such energy sources using thermochemical conversion processes. However, efficient operation of thermochemical conversion systems requires a thorough understanding of the influence of the influence of the composition and thermal properties of rice husks on their behavior during the conversion process. In this study, the thermal behavior of four rice husk varieties (Lemont, ROK 14, CP 4, and Pa Potho) was examined at three heating rates (10, 20, and 50 C/min) in stationary air atmosphere. The thermal degradation rate in active and passive pyrolysis zones, the initial degradation temperature, and the residual weight at 600 C were determined. Increasing the heating rate increased both the thermal degradation rate and the residual weight and decreased the initial degradation temperature. The higher the cellulosic content of the rice husk, the higher the thermal degradation rate and the initial degradation temperature. Also, higher ash content in the rice husk resulted in higher residual weight at 600 C.

  9. Preparing spherical lignin from rice husk.

    PubMed

    Zhang, Hongxi; Zhao, Xu; Ding, Xuefeng; Lei, Hong; Wang, Zichen

    2013-08-01

    Lignin is one of the important branched amorphous polymers, which generally has the irregular and fractal morphology. The preparation of regular sphere of lignin needs long steps and special conditions. In this study, the regular sphere of lignin can be simply prepared from rice husk (RH) under certain conditions. Namely, RH is mixed with 35% ethanol aqueous solution in the proportion of 1:10 (g:mL), non-isothermally heated to 493 K and kept for 5 h. After filtration and air-drying at room temperature, the regular lignin sphere with the diameter of 100-400 nm is obtained. The regular sphere of lignin has the potential utilization in fields such as reactive functional materials, photo sensing materials and surface active materials in cosmetics. The mechanism of formation of the regular spherical lignin is proposed and discussed in this paper.

  10. Nano filter from sintered rice husk silica membrane.

    PubMed

    Lee, Soo Young; Han, Chong Soo

    2006-11-01

    A nano filter showing the Knudsen flow was demonstrated by a modification of a membrane constructed from rice husk silica. The membrane was prepared by pressing and sintering micron sized rice husk silica with 4 nm pores. The membrane showed a permeability of 5.2 x 10(-8) mol m(-1) sec(-1) Pa(-1) for H2 and ratios of gas permeability 2.1 and 3.2 for k(H2)/k(CH4) and k(H2)/k(CO2), respectively. When the membrane was treated by filtration of approximately 100 nm sized rice husk silica particles, the permeability decreased to 4.9 x 10(-8) mol m(-1) sec(-1) Pa(-1) and the ratios increased to 2.2 and 3.4. In the case of the membrane after treatments with the dispersion and chemical deposition of tetraethylorthosilicate (TEOS), the corresponding permeability and ratios of the membrane were 1.8 x 10(-8) mol m(-1) sec(-1) Pa(-1), and 2.9 and 4.5, respectively. From the change of the ratio of gas permeability for the membrane with modifications, it is suggested that approximately 100 nm sized rice husk silica particles pack the large pores among the micron sized rice husk silica particles while the chemical deposition of tetraethylorthosilicate (TEOS) reveals the gas flow through 4 nm pores in the rice husk silica by blocking large pores.

  11. Methane potential and biodegradability of rice straw, rice husk and rice residues from the drying process.

    PubMed

    Contreras, L M; Schelle, H; Sebrango, C R; Pereda, I

    2012-01-01

    Agricultural solid residues are a potential renewable energy source. Rice harvesting and production in Sancti Spíritus province, Cuba, currently generates residues without an environmentally sustainable disposal route. Rice residues (rice straw, rice husk and rice residues from the drying process) are potentially an important carbon source for anaerobic digestion. For this paper, rice residues were placed for 36 days retention time in anaerobic batch reactor environments at both mesophilic (37 °C) and thermophilic (55 °C) conditions. Biogas and methane yield were determined as well as biogas composition. The results showed that rice straw as well as rice residues from the drying process had the highest biogas and methane yield. Temperature played an important role in determining both biogas yield and kinetics. In all cases, rice straw produced the highest yields; under mesophilic conditions the biogas yield was 0.43 m(3) kg(VS)(-1), under thermophilic conditions biogas yield reached 0.52 m(3) kg(VS)(-1). In the case of the rice husk, the biodegradability was very low. Methane content in all batches was kept above 55% vol. All digested material had a high carbon:nitrogen (C:N) ratio, even though significant biodegradation was recorded with the exception of rice husk. A first-order model can be used to describe the rice crop residues fermentation effectively.

  12. A new method of comprehensive utilization of rice husk.

    PubMed

    Li, Ying; Ding, Xuefeng; Guo, Yupeng; Rong, Chunguang; Wang, Lili; Qu, Yuning; Ma, Xiaoyu; Wang, Zichen

    2011-02-28

    Rice husk is an abundant agricultural byproduct. The research on comprehensive utilization of rice husk to prepare xylose, activated carbon and silica was carried out. The hydrolysis conditions of xylan in rice husk to produce xylose were as follows: the concentration of H(2)SO(4) was 3.6% (wt.%), the temperature was 100°C, the ratio of rice husk mass (g) to H(2)SO(4) solution (ml) was 1:5 and the time was 3 h. The hydrolysis degree of xylan reached 95.6%. The resulting residues were used to prepare activated carbons with the BET surface area of 1763 m(2)/g when 50% H(3)PO(4) was impregnated with rice husk with the ratio of 5:1 at 500°C for 0.5 h. The produced carbons had effective adsorption capability to purify the xylose solution. Furthermore, they exhibited good electrochemical performance. After adsorption, activated carbons were calcined to produce silica with the diameter of 30 nm. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Arsenate adsorption onto iron oxide amended rice husk char.

    PubMed

    Cope, Christopher O; Webster, Damon S; Sabatini, David A

    2014-08-01

    In this study, rice husks were charred at 550 °C in a partially sealed ceramic vessel for 30minutes to create a high specific surface area (SSA) rice husk char (RHC). The RHC was then amended with iron oxides using dissolved ferric nitrate, Fe(NO3)3⋅9H2O, to provide a surface chemistry conducive to arsenic adsorption. The 550 °C iron oxide amended rice husk char's (550 IOA-RHC's) SSA was nearly 2.5 orders of magnitude higher and the arsenate adsorptive level was nearly 2 orders of magnitude higher than those reported for iron oxide amended sand, thus indicating a positive relationship between post-amendment SSA and arsenate adsorptive levels. Rice husks were then charred at temperatures ranging from 450 °C to 1050 °C to create an even higher SSA material, which might further increase arsenate adsorptive levels. The 950 °C RHC was chosen for amendment due to its high SSA and feasibility of being produced in the field. Once amended, the 950 °C iron oxide amended rice husk char (950 IOA-RHC) improved the arsenate adsorption capacity by thus confirming a positive relationship, though not a linear relationship, between post-amendment SSA and arsenic adsorptive capacity. Further study demonstrated that post-amendment mesoporous volume and mesoporous surface area appear to be better indicators of arsenic adsorptive capacity than SSA or iron content.

  14. Markets for rice husk-to-energy systems and equipment

    SciTech Connect

    Velupillai, L.; Mahin, D.B.

    1996-12-31

    A worldwide study of markets for U.S. equipment and systems for the production of energy from rice husks was conducted in 1995-96 by a team based at the Louisiana State University (LSU) Agricultural Center in Baton Rouge, Louisiana. The project was carried out in cooperation with Agrilectric Power Inc. and Riceland Foods, Inc., and funded by the U.S. Department of Energy through the National Renewable Energy Laboratory. The study included: (a) a global overview of the rice industry, rice husk availability and utilization, and husk-to-energy technologies, and (b) case studies of husk utilization and potential markets for husk-to-energy systems and equipment in five countries - the United States, Italy, China, Thailand, and Sri Lanka. The case studies in Italy, China, and Thailand were based in each case on a field trip to the country by a member of the project team. The study covered the following husk-to-energy technologies: furnace and boiler systems, steam engine systems, steam turbine systems, and gasifier/engine systems.

  15. Comparative study of various pretreatment reagents on rice husk and structural changes assessment of the optimized pretreated rice husk.

    PubMed

    Ang, Teck Nam; Ngoh, Gek Cheng; Chua, Adeline Seak May

    2013-05-01

    The performance of alkalis (NaOH and Ca(OH)2) and acids (H2SO4, HCl, H3PO4, CH3COOH, and HNO3) in the pretreatment of rice husk was screened, and a suitable reagent was assessed for subsequent optimization using response surface methodology. From the assessment, HCl that hydrolysed rice husk well was optimized with three parameters (HCl loading, pretreatment duration, and temperature) using Box-Behnken Design. The optimized condition (0.5% (w/v) HCl loading, 125 °C, 1.5 h) is relatively mild, and resulted in ~22.3mg TRS/ml hydrolysate. The reduced model developed has good predictability, where the predicted and experimental results differ by only 2%. The comprehensive structural characterization studies that involved FT-IR, XRD, SEM, and BET surface area determination showed that the pretreated rice husk consisted mainly of cellulose and lignin. Compared to untreated rice husk, pretreated rice husk possessed increased pore size and pore volume, which are expected to be beneficial for fungal growth during fermentation.

  16. Electrical properties of Al-, Cu-, Zn- rice husk charcoal junctions

    NASA Astrophysics Data System (ADS)

    Dahonog, L. A.; Tapia, A. K. G.

    2017-04-01

    Rice husk in the Philippines is considered as an agricultural waste. In order to utilize the material, one common technique is to carbonize these rice husks to produce charcoal briquettes. These materials are porous in nature exhibiting electrical properties from carbon structures. In this study, rice husk charcoals (RHC) were deposited on different metal substrates (Al, Cu, Zn) via a simple solution casting method. The deposited RHC on metal substrates was observed using Scanning Electron Microscopy (SEM). The films were characterized using two-point probe technique and the I-V curves were plotted. Al-RHC films appear to deviate from an ohmic behaviour while Zn-RHC and Cu-RHC showed diode-like behaviours.

  17. Study of silica templates in the rice husk and the carbon-silica nanocomposites produced from rice husk

    NASA Astrophysics Data System (ADS)

    Larichev, Yu. V.; Yeletsky, P. M.; Yakovlev, V. A.

    2015-12-01

    Carbon-silica nanocomposites obtained by rice husk carbonization in a fluidized-bed reactor using a deep oxidation copper-chromium catalyst were studied. Dispersion characteristics of the silica phase in these systems were determined by small-angle X-ray scattering (SAXS) using the full contrast technique. SiO2 was found in the initial rice husk as compact nanoparticles having a wide size distribution. This distribution consists of a narrow fraction with particle sizes from 1 to 7 nm and a wider fraction with particle sizes from 8 to 22 nm. Oxidative heat treatment of rice husk in a fluidized bed in the presence of the catalyst decreased the fraction of small SiO2 particles and increased the fraction of large ones. It was demonstrated that the particle size of silica in the carbon matrix can be determined selectively for deliberate design of porous carbon materials with desired properties.

  18. Removal of arsenic from drinking water using rice husk

    NASA Astrophysics Data System (ADS)

    Asif, Zunaira; Chen, Zhi

    2015-09-01

    Rice husk adsorption column method has proved to be a promising solution for arsenic (As) removal over the other conventional methods. The present work investigates the potential of raw rice husk as an adsorbent for the removal of arsenic [As(V)] from drinking water. Effects of various operating parameters such as diameter of column, bed height, flow rate, initial arsenic feed concentration and particle size were investigated using continuous fixed bed column to check the removal efficiency of arsenic. This method shows maximum removal of As, i.e., 90.7 % under the following conditions: rice husk amount 42.5 g; 7 mL/min flow rate in 5 cm diameter column at the bed height of 28 cm for 15 ppb inlet feed concentration. Removal efficiency was increased from 83.4 to 90.7 % by reducing the particle size from 1.18 mm to 710 µm for 15 ppb concentration. Langmuir and Freundlich isotherm models were employed to discuss the adsorption behavior. The effect of different operating parameters on the column adsorption was determined using breakthrough curves. In the present study, three kinetic models Adam-Bohart, Thomas and Yoon-Nelson were applied to find out the saturated concentration, fixed bed adsorption capacity and time required for 50 % adsorbate breakthrough, respectively. At the end, solidification was done for disposal of rice husk.

  19. Removal of arsenic from drinking water using rice husk

    NASA Astrophysics Data System (ADS)

    Asif, Zunaira; Chen, Zhi

    2017-06-01

    Rice husk adsorption column method has proved to be a promising solution for arsenic (As) removal over the other conventional methods. The present work investigates the potential of raw rice husk as an adsorbent for the removal of arsenic [As(V)] from drinking water. Effects of various operating parameters such as diameter of column, bed height, flow rate, initial arsenic feed concentration and particle size were investigated using continuous fixed bed column to check the removal efficiency of arsenic. This method shows maximum removal of As, i.e., 90.7 % under the following conditions: rice husk amount 42.5 g; 7 mL/min flow rate in 5 cm diameter column at the bed height of 28 cm for 15 ppb inlet feed concentration. Removal efficiency was increased from 83.4 to 90.7 % by reducing the particle size from 1.18 mm to 710 µm for 15 ppb concentration. Langmuir and Freundlich isotherm models were employed to discuss the adsorption behavior. The effect of different operating parameters on the column adsorption was determined using breakthrough curves. In the present study, three kinetic models Adam-Bohart, Thomas and Yoon-Nelson were applied to find out the saturated concentration, fixed bed adsorption capacity and time required for 50 % adsorbate breakthrough, respectively. At the end, solidification was done for disposal of rice husk.

  20. Phenolic acids and antioxidant activities in husk of different Thai rice varieties.

    PubMed

    Butsat, S; Siriamornpun, S

    2010-08-01

    This study was designed to investigate the free and bound phenolic acids as well as their antioxidant activities in husk of 12 Thai rice varieties consisting of pigmented rice and normal rice. The pigmented rice husk gave higher free total phenolic contents than normal rice husk. However, there was no significant difference in bound total phenolic contents between pigmented rice and normal rice husks. Ferulic and p-coumaric acids were the major phenolic acids in the free fraction of pigmented rice husks, whereas vanillic acid was the dominant phenolic acid in the free fraction of normal rice husks. On the other hand, p-coumaric acid was highly found in bound form of both pigmented and normal rice husks. The antioxidant activity of husk extracts was positively correlated with the total free phenolics content and individual of phenolic acids especially ferulic acid. On the basis of this study, it is suggested that the rice husk could be a potential phenolic acid source and may therefore offer an effective source of natural antioxidant. Our findings provide valuable information on phenolic acids composition and antioxidant activity of husk for further food application.

  1. [Adsorption-desorption Characteristics of Fermented Rice Husk for Ferrous and Sulfur Ions].

    PubMed

    Xie, Xiao-mei; Liao, Min; Hua, Jia-yuan; Chen, Na; Zhang, Nan; Xu, Pei-zhi; Xie Kai-zhi; XU, Chang-xu; Liu, Guang-rong

    2015-10-01

    To understand the potential of rice husk to fix Fe2+ and S2- ions, the sorption of Fe2+ and S2- by fermented rice husk was studied by using batch incubation experiments in the present study. The effects of adsorption time, Fe2+ and S2- concentration, pH, the temperature and ionic strength in adsorption reaction solution on the sorption were investigated. Therefore, the stability of Fe2+ and S2- adsorbed by fermented rice husk was further validated by desorption experiments performed under similar conditions as adsorption. The results showed that, the adsorption kinetics of Fe2+ (r = 0.912 1) and S2- (r = 0.901 1) by fermented rice husk fits the Elovich kinetics equation, and Freundlich isotherm model could simulate the isotherm adsorption processes of Fe2+ (R2 = 0.965 1) and S2- (R2 = 0.936 6) on fermented rice husk was better than other models. The adsorption processes on fermented rice husk were non- preferential adsorption for Fe2+ and S2, while the adsorption process of Fe2+ on fermented rice husk was spontaneous reaction and the adsorption process of S2- was non-spontaneous reaction. The adsorption processes of Fe2+ and S2- on fermented rice husk were endothermic process since high temperature could benefit to the adsorption. The adsorption mechanism of Fe2+ on fermented rice husk was mainly controlled by coordination adsorption, the adsorption mechanism of S2- on fermented rice husk was mainly controlled by ligand exchange adsorption. The adsorption processes of Fe2+ and S2- on fermented rice husk showed greater pH adaptability which ranged from 1.50 to 11.50. With the increasing of ionic strength, the amount of adsorbed Fe2+ on fermented rice husk wasincreased in some extent, the amount of adsorbed S2- on fermented rice husk was slightly decreased, which further proved the adsorption of Fe2+ was major in inner sphere complexation and the adsorption of S2- was major in outer complexation. The desorption rates of Fe2+ and S2- which was adsorbed by fermented

  2. Development of rice husks-plastics composites for building materials.

    PubMed

    Choi, Nak-Woon; Mori, Ippei; Ohama, Yoshihiko

    2006-01-01

    In this paper, a new effective recycling method for rice husks and waste expanded polystyrene is developed by using a combination of both wastes. A styrene solution of waste expanded polystyrene is used as a binder for rice husks-plastics composites. The composites are prepared with various mix proportions by a hot press molding method, and tested for apparent density, water absorption, expansion in thickness, and dry and wet flexural strengths. From the test results, the apparent density of the composites is increased with increasing binder content and filler-binder ratio. Their flexural strength and wet flexural strengths reach maximums at a binder content of 30.0% and a filler-binder ratio of 1.0. Their water absorption and expansion in thickness are decreased with increasing binder content and filler-binder ratio. Since the composites have a high flexural strength and water resistance, their uses as building materials are expected.

  3. Magnesiothermic reduction of rice husk ash for electromagnetic wave adsorption

    NASA Astrophysics Data System (ADS)

    Liu, Shu-Ting; Yan, Kang-kang; Zhang, Yuan hu; Jin, Shi-di; Ye, Ying; Chen, Xue-Gang

    2015-11-01

    The increase in electromagnetic pollution due to the extensive exploitation of electromagnetic (EM) waves in modern technology creates correspondingly urgent need for developing effective EM wave absorbers. In this study, we carried out the magnesiothermic reduced the rice husk ash under different temperatures (400-800 °C) and investigated the electromagnetic wave adsorption of the products. The EM absorbing for all samples are mainly depend on the dielectric loss, which is ascribed to the carbon and silicon carbide content. RA samples (raw rice husk ashed in air and was magesiothermic reduced in different temperatures) exhibit poor dielectric properties, whereas RN samples (raw rice husk ashed in nitrogen and was magesiothermic reduced in different temperatures) with higher content of carbon and silicon carbide display considerable higher dielectric loss values and broader bandwidth for RL<-5 dB and -10 dB. For RN samples, the maximum bandwidth for -5 dB and -10 dB decrease with carbon contents, while the optimum thickness decrease with increasing SiC content. The optimum thickness of RN400-800 for EM absorption is 1.5-2.0 mm, with maximum RL of between -28.9 and -68.4 dB, bandwidth of 6.7-13 GHz for RL<-5 dB and 3.2-6.2 GHz for RL<-10 dB. The magnesiothermic reduction will enhance the potential application of rice husk ash in EM wave absorption and the samples benefited from low bulk density and low thickness. With the advantages of light-weight, high EM wave absorption, low cost, RN400-800 could be promising candidates for light-weight EM wave absorption materials over many conventional EM wave absorbers.

  4. Characteristics of rice husk gasification in an entrained flow reactor.

    PubMed

    Zhao, Yijun; Sun, Shaozeng; Tian, Hongming; Qian, Juan; Su, Fengming; Ling, Feng

    2009-12-01

    Experiments were performed in an entrained flow reactor to better understand the characteristics of biomass gasification. Rice husk was used in this study. Effects of the gasification temperature (700, 800, 900 and 1000 degrees C) and the equivalence ratio in the range of 0.22-0.34 on the biomass gasification and the axial gas distribution in the reactor were studied. The results showed that reactions of CnHm were less important in the gasification process except cracking reactions which occurred at higher temperature. In the oxidization zone, reactions between char and oxygen had a more prevailing role. The optimal gasification temperature of the rice husk could be above 900 degrees C, and the optimal value of ER was 0.25. The gasification process was finished in 1.42 s when the gasification temperature was above 800 degrees C. A first order kinetic model was developed for describing rice husk air gasification characteristics and the relevant kinetic parameters were determined.

  5. Biosorption studies on copper (II) and cadmium (II) using pretreated rice straw and rice husk.

    PubMed

    Li, W C; Law, F Y; Chan, Y H M

    2015-07-25

    This study investigated the adsorption and removal behaviour of copper (Cu) (II) and cadmium (Cd) (II) ions using rice husk and rice straw in aqueous solutions. Different parameters were used to investigate their adsorption performance in saline conditions and the optimal level of biosorption at different pH levels. The main parameters were pH (3, 6 and 9), initial concentration level of heavy metals (Cu (II) 5, 10, 20, 40 and 60 mg/L and Cd (II) 0.5, 1, 2, 4 and 8 mg/L, respectively), salinity (0, 50 and 100 mM NaCl) and contact time (ranging from 3 to 60 min). Langmuir and Freundlich isotherm models were applied to analyse the removal efficiency and sorption capacity of the pretreated rice husk and rice straw. The removal efficiency and adsorption capacity generally increased with the pH and reached a plateau in alkaline conditions. The percentage removal of Cu (II) by rice husk reached 97 % at pH 9 and 95 % by rice straw at pH 6. Biosorption performance increased in the absence of NaCl. Kinetic studies for both metals revealed that the biosorption of Cu (II) and Cd (II) onto rice straw and husk was pseudo-second order.

  6. Rice husk-originating silicon-graphite composites for advanced lithium ion battery anodes.

    PubMed

    Kim, Hye Jin; Choi, Jin Hyeok; Choi, Jang Wook

    2017-01-01

    Rice husk is produced in a massive amount worldwide as a byproduct of rice cultivation. Rice husk contains approximately 20 wt% of mesoporous SiO2. We produce mesoporous silicon (Si) by reducing the rice husk-originating SiO2 using a magnesio-milling process. Taking advantage of meso-porosity and large available quantity, we apply rice husk-originating Si to lithium ion battery anodes in a composite form with commercial graphite. By varying the mass ratio between these two components, trade-off relation between specific capacity and cycle life was observed. A controllable pre-lithiation scheme was adopted to increase the initial Coulombic efficiency and energy density. The series of electrochemical results suggest that rice husk-originating Si-graphite composites are promising candidates for high capacity lithium ion battery anodes, with the prominent advantages in battery performance and scalability.

  7. Alkaline peroxide assisted wet air oxidation pretreatment approach to enhance enzymatic convertibility of rice husk.

    PubMed

    Banerjee, Saumita; Sen, Ramkrishna; Mudliar, Sandeep; Pandey, R A; Chakrabarti, Tapan; Satpute, Dewanand

    2011-01-01

    Pretreatment of rice husk by alkaline peroxide assisted wet air oxidation (APAWAO) approach was investigated with the aim to enhance the enzymatic convertibility of cellulose in pretreated rice husk. Rice husk was presoaked overnight in 1% (w/v) H(2)O(2) solution (pH adjusted to 11.5 using NaOH) (equivalent to 16.67 g H(2)O(2) and 3.63 g NaOH per 100 g dry, untreated rice husk) at room temperature, followed by wet air oxidation (WAO). APAWAO pretreatment resulted in solubilization of 67 wt % of hemicellulose and 88 wt % of lignin initially present in raw rice husk. Some amount of oligomeric glucose (˜8.3 g/L) was also observed in the APAWAO liquid fraction. APAWAO pretreatment resulted in 13-fold increase in the amount of glucose that could be obtained from otherwise untreated rice husk. Up to 86 wt % of cellulose in the pretreated rice husk (solid fraction) could be converted into glucose within 24 hours, yielding over 21 g glucose per 100 g original rice husk. Scanning electron microscopy was performed to visualize changes in biomass structure following the APAWAO pretreatment. Enzymatic cellulose convertibility of the pretreated slurry at high dry matter loadings was also investigated.

  8. Experimental research on rice husk combustion in CFB boiler and the design of a 35 t/h rice husk-fired CFB boiler

    SciTech Connect

    Chen Guanyi; Fang Mengxiang; Luo Zhongyang; Li Xuantian; Shi Zhenglun; Cen Kefa; Ni Mingjiang

    1997-12-31

    The fluidization and transportation properties of rice husk have been studied on a cold model bed of inner diameter 120 mm. The ignition and combustion characteristics of rice husk mixed with coal have also been studied in a 1 MW experimental circulating fluidized bed (CFB) system. The conclusions, drawn on the basis of these experiments, are found to be very useful for the design of a 35 tons per hour CFB boiler firing this biomass fuel.

  9. Biosorption of zinc from aqueous solution using chemically treated rice husk.

    PubMed

    Zhang, Ying; Zheng, Ru; Zhao, Jiaying; Zhang, Yingchao; Wong, Po-Keung; Ma, Fang

    2013-01-01

    In this study, adsorption of zinc onto the adsorbent (untreated rice husk and NaOH-treated rice husk) was examined. During the removal process, batch technique was used, and the effects of pH and contact time were investigated. Langmuir isotherm was applied in order to determine the efficiency of NaOH-treated rice husk used as an adsorbent. The zinc adsorption was fast, and equilibrium was attained within 30 min. The maximum removal ratios of zinc for untreated rice husk and NaOH-treated rice husk after 1.5 h were 52.3% and 95.2%, respectively, with initial zinc concentration of 25 mg/L and optimum pH of 4.0. Data obtained from batch adsorption experiments fitted well with the Langmuir isotherm model. Maximum adsorption capacity of zinc onto untreated rice husk and NaOH-treated rice husk was 12.41 mg/g, and 20.08 mg/g respectively, at adsorbent dosage of 1 g/L at 25°C. The nature of functional groups (i.e., amino, carboxyl, and hydroxyl) and metal ion interactions was examined by the FT-IR technique. It was concluded that the NaOH-treated rice husk had stronger adsorption capacity for Zn(2+) compared with the untreated rice husk. The NaOH-treated rice husk is an inexpensive and environmentally friendly adsorbent for Zn(2+) removal from aqueous solutions.

  10. Nanostructured silicon nitride from wheat and rice husks

    NASA Astrophysics Data System (ADS)

    Qadri, S. B.; Rath, B. B.; Gorzkowski, E. P.; Wollmershauser, J. A.; Feng, C. R.

    2016-04-01

    Nanoparticles, submicron-diameter tubes, and rods of Si3N4 were synthesized from the thermal treatment of wheat and rice husks at temperatures at and above 1300 °C in a nitrogen atmosphere. The whole pattern Rietveld analysis of the observed diffraction data from treatments at 1300 °C showed the formation of only hexagonal α-phase of Si3N4 with an R-factor of 1%, whereas samples treated at 1400 °C and above showed both α- and β-phases with an R-factor of 2%. Transmission electron microscopy showed the presence of tubes, rods, and nanoparticles of Si3N4. In a two-step process, where pure SiC was produced first from rice or wheat husk in an argon atmosphere and subsequently treated in a nitrogen atmosphere at 1450 °C, a nanostructured composite material having α- and β-phases of Si3N4 combined with cubic phase of SiC was formed. The thermodynamics of the formation of silicon nitride is discussed in terms of the solid state reaction between organic matter (silica content), which is inherently present in the wheat and rice husks, with the nitrogen from the furnace atmosphere. Nanostructures of silicon nitride formed by a single direct reaction or their composites with SiC formed in a two-step process of agricultural byproducts provide an uncomplicated sustainable synthesis route for silicon nitride used in mechanical, biotechnology, and electro-optic nanotechnology applications.

  11. Nanostructured silicon nitride from wheat and rice husks

    SciTech Connect

    Qadri, S. B.; Rath, B. B.; Gorzkowski, E. P.; Wollmershauser, J. A.; Feng, C. R.

    2016-04-07

    Nanoparticles, submicron-diameter tubes, and rods of Si{sub 3}N{sub 4} were synthesized from the thermal treatment of wheat and rice husks at temperatures at and above 1300 °C in a nitrogen atmosphere. The whole pattern Rietveld analysis of the observed diffraction data from treatments at 1300 °C showed the formation of only hexagonal α-phase of Si{sub 3}N{sub 4} with an R-factor of 1%, whereas samples treated at 1400 °C and above showed both α- and β-phases with an R-factor of 2%. Transmission electron microscopy showed the presence of tubes, rods, and nanoparticles of Si{sub 3}N{sub 4}. In a two-step process, where pure SiC was produced first from rice or wheat husk in an argon atmosphere and subsequently treated in a nitrogen atmosphere at 1450 °C, a nanostructured composite material having α- and β-phases of Si{sub 3}N{sub 4} combined with cubic phase of SiC was formed. The thermodynamics of the formation of silicon nitride is discussed in terms of the solid state reaction between organic matter (silica content), which is inherently present in the wheat and rice husks, with the nitrogen from the furnace atmosphere. Nanostructures of silicon nitride formed by a single direct reaction or their composites with SiC formed in a two-step process of agricultural byproducts provide an uncomplicated sustainable synthesis route for silicon nitride used in mechanical, biotechnology, and electro-optic nanotechnology applications.

  12. Stability studies of immobilized lipase on rice husk and eggshell membrane

    NASA Astrophysics Data System (ADS)

    Abdulla, R.; Sanny, S. A.; Derman, E.

    2017-06-01

    Lipase immobilization for biodiesel production is gaining importance day by day. In this study, lipase from Burkholderia cepacia was immobilized on activated support materials namely rice husk and egg shell membrane. Both rice husk and eggshell membrane are natural wastes that holds a lot of potential as immobilization matrix. Rice husk and eggshell membrane were activated with glutaraldehyde. Lipase was immobilized on the glutaraldehyde-activated support material through adsorption. Immobilization efficiency together with enzyme activity was observed to choose the highest enzyme loading for further stability studies. Immobilization efficiency of lipase on rice husk was 81 as compared to an immobilization efficiency of 87 on eggshell membrane. Immobilized lipase on eggshell membrane exhibited higher enzyme activity as compared to immobilized lipase on rice husk. Eggshell membrane also reported higher stability than rice husk as immobilization matrix. Both types of immobilized lipase retatined its activity after ten cycles of reuse. In short, eggshell membrane showed to be a better immobilization platform for lipase as compared to rice husk. However, with further improvement in technique of immobilization, the stability of both types of immobilized lipase can be improved to a greater extent.

  13. High quality syngas production from microwave pyrolysis of rice husk with char-supported metallic catalysts.

    PubMed

    Zhang, Shuping; Dong, Qing; Zhang, Li; Xiong, Yuanquan

    2015-09-01

    This study aimed to obtain the maximum possible gas yield and the high quality syngas production from microwave pyrolysis of rice husk with rice husk char and rice husk char-supported metallic (Ni, Fe and Cu) catalysts. The rice husk char-supported metallic catalysts had developed pore structure and catalytic activity for gas productions and tar conversion. The temperature-rising characteristic, product yields, properties of gas products and tar conversion mechanisms were investigated. It was found that three rice husk char-supported metallic catalysts improved the microwave absorption capability and increased heating rate and final temperature. Rice husk char-supported Ni catalyst presented most effective effects on gas production, e.g. the gas yield is 53.9%, and the volume concentration of desired syngas is 69.96%. Rice husk char-supported Ni and Fe catalysts played pivotal roles in tar conversion that less heavy compounds can be detected along with the reduction of organic compound number.

  14. Utilization of Rice Husk as Pb Adsorbent in Blood Cockles

    NASA Astrophysics Data System (ADS)

    Rohaeti, Eti; Permata Sari, Wenny; Batubara, Irmanida

    2016-01-01

    Water pollution by lead affects blood cockles, a potential source of food. The aim of this research is to compare rice husk (RH) and rice husk carbon (RHC) in reducing the concentration of lead in blood cockles. RH and RHC were activated with NaOH 1 M, and then the optimal conditions and maximum capacity were determined. This research showed that RH and RHC had maximum adsorbancy capacities of 28.7326 mg/g and 51.5464 mg/g at optimal condition. The optimal adsorption condition for RH in 100 ml Pb solution is 0.32 gram, pH 5, for 4 hours. The optimal adsorption condition for RHC in 100 ml Pb solution is 0.20 gram, pH 5, for 2 hours. Lead content in blood cockles from the north waters of Jakarta (1.9658 mg/kg) is beyond the threshold limit. Lead adsorption by RH and RHC could reduce lead content in blood cockles by about 40% and 31%, respectively.

  15. Synthesis of High Purity Silicon from Rice Husks

    NASA Astrophysics Data System (ADS)

    Larbi, Kingsley Kweku

    Impurity optimized silicon is needed for the advancement of terrestrial photovoltaic power generation. In this study the possibility of producing solar grade silicon from rice husks has been pursued. An integrated process flowsheet was developed and practiced that included initial leaching, reduction of Rice husk ash (RHA) and post-reduction purification of silicon. Metallothermic reduction of purified RHA with magnesium was investigated within the temperature range of 500-950 °C. The reduction product was purified by two stage acid leaching sequence. Analysis of the final silicon powder product by XRD and ICP-OES showed crystalline silicon with boron content to be less than 3ppm- corresponding to reduction by a factor greater than 10, whilst the phosphorus content was reduced by a factor of over 20 and reaching less than 73ppm. The effects of temperature, magnesium amount and leaching agents optimized in this study. A one step test melting was also carried out to convert the silicon powder into silicon chunks.

  16. Production of activated carbon from rice husk Vietnam

    NASA Astrophysics Data System (ADS)

    Korobochkin, V. V.; Tu, N. V.; Hieu, N. M.

    2016-09-01

    This work is dedicated to the production of activated carbon from rice husk from Delta of the Red River in Viet Nam. At the first stage, carbonization of a rice husk was carried out to obtain material containing 43.1% carbon and 25 % silica with a specific surface area of 51.5 m2/g. After separating of silica (the second stage), the specific surface area of the product increased to 204 m2/g and the silica content decreased to 1.23% by weight as well. The most important stage in the formation of the porous structure of the material is the activation. The products with the high specific surface area in the range of 800-1345 m2/g were obtained by activation of carbonized product with water vapour or carbon dioxide at temperatures of 700 °C and 850 °C, with varying the flow rate of the activating agent and activation time. The best results were achieved by activation of carbon material with water vapour at the flow rate of 0.08 dm3/min per 500 g of material and the temperature of 850 °C.

  17. Sorption kinetics of Zn (II) ion by thermally treated rice husk

    NASA Astrophysics Data System (ADS)

    Ong, K. K.; Tarmizi, A. F. A.; Wan Yunus W. M., Z.; Safidin, K. M.; Fitrianto, A.; Hussin, A. G. A.; Azmi, F. M.

    2015-05-01

    Agricultural wastes such as orange peels, tea leave waste, rice husk and corn cobs have been widely studied as sorbents for heavy metal ion removal from various wastewaters. In order to understand their sorption mechanism, the adsorption kinetics is studied. This report describes the kinetics study of a thermally treated rice husk to adsorb Zn (II) ion from an aqueous solution. The adsorbent was obtained by heating the rice husk in a furnace at 500°C for two hours. Increase the contact period improved percentage of the removal of Zn (II) ion until an equilibrium was reached. The data obtained showed that the adsorption of Zn (II) ion by thermally treated rice husk obeyed pseudo-second order kinetics model, which is in agreement with chemisorption as the rate limiting mechanism.

  18. Production of micro- and nanosilica from soil inhabiting Folsomia candida fed with treated rice husk.

    PubMed

    Moreno-Murguía, Barbara; Soto-Mercado, Jorge R; Morales-Malacara, Juan B; Castaño, Victor M

    2015-08-01

    Rice husk was employed as a source for producing silica micro- and nanoparticles through its digestion by soil fauna. Although many physicochemical methods for producing nanostructures have been studied, the biological processes remain mostly unexplored. Alkaline hydrogen peroxide with continuous control of reaction pH allowed removal of lignin bonds while preserving most of the cell wall and the silica present in the rice husk. The accessibility of lignocellulose was achieved without removing appreciable amounts of lignin, so this agricultural byproduct can be employed as feeding material for microarthropods Folsomia candida (Collembola). When these microarthropods are placed on a substrate of treated rice husk, more than 85% of degraded material is obtained, as compared to the untreated rice husk substrate, while the silica particles obtained show a slight decrease in average size.

  19. Evaluation of rice husk ash as filler in tread compounds

    SciTech Connect

    Fernandes, M. R. S.; Furtado, C. R. G. E-mail: ana.furtado.sousa@gmail.com; Sousa, A. M. F. de E-mail: ana.furtado.sousa@gmail.com

    2014-05-15

    Rice which is one of the largest agriculture crops produces around 22% of rice rusk during its milling process. This material is mainly used as fuel for energy generation, which results in an ash, which disposal represents an environmental issue. The rice husk ash (RHA) contains over than 70% of silica in an amorphous form and a lot of applications is being developed for it all over the world. The use of silica as a filler in the tire industry is growing since it contributes significantly to the reduction of fuel consumption of the automobiles, allowing at the same time better traction (safety). This paper presents an evaluation of the use of RHA as filler in rubber tread compounds prepared in lab scale and compares its performance with compounds prepared with commercial silica and carbon black, the fillers normally used in tire industry. Mechanical and rheological properties are evaluated, with emphasis for tan delta as an indicator of tread performance related with rolling resistance (fuel consumption) and wet grip/traction (safety)

  20. A new route for preparation of hydrochars from rice husk.

    PubMed

    Wang, Lili; Guo, Yupeng; Zhu, Yanchao; Li, Ying; Qu, Yuning; Rong, Chunguang; Ma, Xiaoyu; Wang, Zichen

    2010-12-01

    In the present work, a green and sustainable route for preparation of hydrochars from sulfuric acid hydrolysis solution of rice husk under low temperature and atmospheric pressure was described. This route was achieved with the catalysis of sulfuric acid. The sphere-like carbon materials with regular size of about 500 nm were obtained at 95 degrees C for 6h when the acid concentration was 42% and 52%. The morphology of the hydrochars changed with sulfuric acid concentration increased. The surface of the materials contained a large number of functional groups. Furthermore, the localized graphitic nature of the materials was proved by X-ray diffraction pattern. High surface area porous carbons could be prepared from the hydrochars after activation, and they exhibited good electrochemical performance.

  1. Development of high volume rice husk ash alumino silicate composites

    NASA Astrophysics Data System (ADS)

    Rattanasak, Ubolluk; Chindaprasirt, Prinya; Suwanvitaya, Prasert

    2010-10-01

    The development of high volume rice husk ash (RHA) alumino silicate composites (ASC) was studied. RHA was used as the source of silica and aluminium in the ASC. The mass ratios of RHA:Al(OH)3 of 70:30 to 99:1 were tested. The results indicate that the obtained ASC mortars are not stable and disintegrate in water. Boric acid was introduced to the mixture to overcome this problem. Stable ASC mortars with high RHA:Al(OH)3 mass ratios of 90:10 to 97.5:2.5 were obtained with the use of boric acid and 115°C curing. The compressive strength of the mortar of 20 MPa was gained. The immersion test indicates that high volume RHA ASC mortars show good resistance in 3vol% H2SO4 solution, but is slightly less durable in 5wt% MgSO4 solution.

  2. Medium-density particleboards from modified rice husks and soybean protein concentrate-based adhesives.

    PubMed

    Ciannamea, Emiliano M; Stefani, Pablo M; Ruseckaite, Roxana A

    2010-01-01

    The main goal of this work was to evaluate the technical feasibility of using rice husk (RH) as wood substitute in the production of environmentally sound medium-density particleboards using adhesives from soybean protein concentrate (SPC). Chemical modification of rice husk with sodium hydroxide and sodium hydroxide followed by hydrogen peroxide (bleaching) were undertaken to evaluate the effect of such treatments on the composition and topology of rice husk and the performance of produced panels. Both treatments were efficient in partially eliminating hemicelluloses, lignin and silica from RH, as evidenced by thermo-gravimetric analysis (TGA). Scanning electron microscopy observations suggested that alkaline treatment resulted in a more damaged RH substrate than bleaching. The dependence of mechanical properties (modulus of rupture, modulus of elasticity, and internal bond) and the physical properties (water absorption and thickness swelling) on chemical treatments performed on both, rice husk and SPC was studied. Bleached-rice husk particleboards bonded with alkaline-treated soybean protein concentrate displayed the best set of final properties. Particleboards with this formulation met the minimum requirements of internal bond, modulus of elasticity and modulus of rupture recommended by the US Standard ANSI/A208.1 specifications for M1, MS and M2-grade medium-density particleboards, but failed to achieve the thickness swelling value recommended for general use panels. This limitation of soybean protein concentrate-bonded rice husk particleboards was counterbalanced by the advantage of being formaldehyde-free which makes them a suitable alternative for indoor applications.

  3. Comparative study on the thermal degradation of rice husks in various atmospheres

    SciTech Connect

    Ghaly, A.E.; Mansaray, K.G.

    1999-12-01

    Evaluation is presented of the thermogravimetric behavior of four types of rice husk (Lemont, ROK 14, CP 4, and Pa Potho) at three heating rates (10, 20, and 50 C/min) in air, oxygen, and nitrogen atmospheres. The thermal degradation rate in active and passive zones, the initial degradation temperature, and the residual weight at 700 C were determined. These thermal degradation indices are dependent on the heating rate, atmosphere employed, inorganic substances in rice husk, and chemical composition of rice husk. The initial degradation temperature decreased, while both the thermal degradation rate and the residual weight at 700 C increased when the heating rate was increased. The higher the cellulosic content of the rice husk, the higher the thermal degradation rate and the initial degradation temperature. Also, higher ash content in the rice husk resulted in a higher residual weight at 700 C. The thermal degradation rate in the active zone was higher in the presence of oxygen than in the presence of air and nitrogen. More residual weight was recorded in the nitrogen atmosphere compared to the oxidative atmospheres of the air and oxygen atmospheres. The residual weights of the rice husk samples at 700 C in air and oxygen atmospheres were lower than their initial ash contents, with percentages of ash lost ranging from about 2.95 to 13.10% in the case of air and 4.20 to 17.05% in the case of oxygen.

  4. Bioethanol production from steam-exploded rice husk by recombinant Escherichia coli KO11.

    PubMed

    Tabata, Takamitsu; Yoshiba, Yusuke; Takashina, Tomonori; Hieda, Kazuo; Shimizu, Norio

    2017-03-01

    Rice husk is one of the most abundant types of lignocellulosic biomass. Because of its significant amount of sugars, such as cellulose and hemicellulose, it can be used for the production of biofuels such as bioethanol. However, the complex structure of lignocellulosic biomass, consisting of cellulose, hemicellulose and lignin, is resistant to degradation, which limits biomass utilization for ethanol production. The protection of cellulose by lignin contributes to the recalcitrance of lignocelluloses to hydrolysis. Therefore, we conducted steam-explosion treatment as pretreatment of rice husk. However, recombinant Escherichia coli KO11 did not ferment the reducing sugar solution obtained by enzymatic saccharification of steam-exploded rice husk. When the steam-exploded rice husk was washed with hot water to remove inhibitory substances and M9 medium (without glucose) was used as a fermentation medium, E. coli KO11 completely fermented the reducing sugar solution obtained by enzymatic saccharification of hot water washing-treated steam-exploded rice husk to ethanol. We report here the efficient production of bioethanol using steam-exploded rice husk.

  5. Activation of eosinophils by rice-husk dust exposure: a possible mechanism for the aggravation of asthma during rice harvest.

    PubMed

    Kayaba, Hiroyuki; Meguro, Hitomi; Muto, Hajime; Kamada, Yumiko; Adachi, Tetsuya; Yamada, Yoshiyuki; Kanda, Akira; Yamaguchi, Kazutoshi; Hamada, Kazuyuki; Ueki, Shigeharu; Chihara, Junichi

    2004-09-01

    Grain dust and other irritants affect the airway of allergic patients in rice-growing area during the harvest. The aim of this study was to elucidate the mechanism of airway hypersensitivity in rice-growing areas during the harvest. Firstly, the effect of rice-husk dust on eosinophil activation was studied. Secondary, the concentration of lipopolysaccharides (LPS), a potent activator of inflammatory cells, in rice-husk dust was measured. Since it is possible for LPS, a component of gram-negative bacterial cell wall, to adhere to the particle of smoke generated from rice-husk dust, LPS contained in the smoke was also measured. Furthermore, chemical irritants contained in the smoke generated from the rice-husk dust were analyzed. Microscopically, the dust contained fine thorns dropped off from the outer sheath of the rice, and irritated the skin, throat and eyes. The grain dust extract increased the expressions of eosinophil activation markers. These up-regulatory effects were largely dependent on LPS. The smoke contained LPS and several chemical irritants such as formaldehyde and acetaldehyde. Rice-husk dust and its smoke, hazardous air pollutants, probably play a major role in the aggravation of airway diseases in agricultural areas.

  6. Simultaneous pretreatment and sacchariffication of rice husk by Phanerochete chrysosporium for improved production of reducing sugars.

    PubMed

    Potumarthi, Ravichandra; Baadhe, Rama Raju; Nayak, Priyanka; Jetty, Annapurna

    2013-01-01

    Phanerochete chrysosporium, the white-rot fungus, (a best source for lignolytic enzymes system) was used in the biological pretreatment of rice husk for reducing sugars production. Usually reducing sugar production through biochemical process involves two steps: solid state fermentation (SSF) of fungal pretreatment for delignification, subsequently pretreated biomass subjected to enzymatic hydrolysis. During the fungal pretreatment of rice husk for reducing sugar production along with cellulase and xylanse, the activities of lignin degradation-related enzymes such as lignin peroxidases (LiP), GLOX (glyoxidase), and aryl alcohol oxidases (AAO), were observed. The fungal pretreated rice husk produced highest (895.9 mg/ml/2g of rise husk) reducing sugars on 18th day of fungal treatment. This method may be good alternative to avoid operational costs associated with washing and the removal of inhibitors during the conventional pretreatment methods.

  7. Cellulose fibers extracted from rice and oat husks and their application in hydrogel.

    PubMed

    Oliveira, Jean Paulo de; Bruni, Graziella Pinheiro; Lima, Karina Oliveira; Halal, Shanise Lisie Mello El; Rosa, Gabriela Silveira da; Dias, Alvaro Renato Guerra; Zavareze, Elessandra da Rosa

    2017-04-15

    The commercial cellulose fibers and cellulose fibers extracted from rice and oat husks were analyzed by chemical composition, morphology, functional groups, crystallinity and thermal properties. The cellulose fibers from rice and oat husks were used to produce hydrogels with poly (vinyl alcohol). The fibers presented different structural, crystallinity, and thermal properties, depending on the cellulose source. The hydrogel from rice cellulose fibers had a network structure with a similar agglomeration sponge, with more homogeneous pores compared to the hydrogel from oat cellulose fibers. The hydrogels prepared from the cellulose extracted from rice and oat husks showed water absorption capacity of 141.6-392.1% and high opacity. The highest water absorption capacity and maximum stress the compression were presented by rice cellulose hydrogel at 25°C. These results show that the use of agro-industrial residues is promising for the biomaterial field, especially in the preparation of hydrogels.

  8. Energy potential from rice husk through direct combustion and fast pyrolysis: A review.

    PubMed

    Quispe, Isabel; Navia, Rodrigo; Kahhat, Ramzy

    2017-01-01

    Rapid population growth and consumption of goods and services imply that demand for energy and resources increases continuously. Energy consumption linked to non-renewable resources contributes to greenhouse gas emissions and enhances resource depletion. In this context, the use of agricultural solid residues such as rice husk, coffee husk, wheat straw, sugar cane bagasse, among others, has been widely studied as an alternative energy source in order to decrease the use of fossil fuels. However, rice husk is among those agricultural residues that are least used to obtain energy in developing countries. Approximately 134 million tonnes of rice husk are produced annually in the world, of which over 90% are burned in open air or discharged into rivers and oceans in order to dispose of them. This review examines the energetic potential of agricultural residues, focused on rice husk. The review describes direct combustion and fast pyrolysis technologies to transform rice husk into energy considering its physical and chemical properties. In addition, a review of existing studies analyzing these technologies from an environmental life cycle thinking perspective, contributing to their sustainable use, is performed.

  9. Durability of conventional concretes containing black rice husk ash.

    PubMed

    Chatveera, B; Lertwattanaruk, P

    2011-01-01

    In this study, black rice husk ash (BRHA) from a rice mill in Thailand was ground and used as a partial cement replacement. The durability of conventional concretes with high water-binder ratios was investigated including drying shrinkage, autogenous shrinkage, depth of carbonation, and weight loss of concretes exposed to hydrochloric (HCl) and sulfuric (H(2)SO(4)) acid attacks. Two different replacement percentages of cement by BRHA, 20% and 40%, and three different water-binder ratios (0.6, 0.7 and 0.8) were used. The ratios of paste volume to void content of the compacted aggregate (γ) were 1.2, 1.4, and 1.6. As a result, when increasing the percentage replacement of BRHA, the drying shrinkage and depth of carbonation reaction of concretes increased. However, the BRHA provides a positive effect on the autogenous shrinkage and weight loss of concretes exposed to hydrochloric and sulfuric acid attacks. In addition, the resistance to acid attack was directly varied with the (SiO(2) + Al(2)O(3) + Fe(2)O(3))/CaO ratio. Results show that ground BRHA can be applied as a pozzolanic material and also improve the durability of concrete. Copyright © 2010 Elsevier Ltd. All rights reserved.

  10. Elucidation of the effect of ionic liquid pretreatment on rice husk via structural analyses

    PubMed Central

    2012-01-01

    Background In the present study, three ionic liquids, namely 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc), and 1-ethyl-3-methylimidazolium diethyl phosphate ([EMIM]DEP), were used to partially dissolve rice husk, after which the cellulose were regenerated by the addition of water. The aim of the investigation is to examine the implications of the ionic liquid pretreatments on rice husk composition and structure. Results From the attenuated total reflectance Fourier transform-infrared (ATR FT-IR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM) results, the regenerated cellulose were more amorphous, less crystalline, and possessed higher structural disruption compared with untreated rice husk. The major component of regenerated cellulose from [BMIM]Cl and [EMIM]DEP pretreatments was cellulose-rich material, while cellulose regenerated from [EMIM]OAc was a matrix of cellulose and lignin. Cellulose regenerated from ionic pretreatments could be saccharified via enzymatic hydrolysis, and resulted in relatively high reducing sugars yields, whereas enzymatic hydrolysis of untreated rice husk did not yield reducing sugars. Rice husk residues generated from the ionic liquid pretreatments had similar chemical composition and amorphousity to that of untreated rice husk, but with varying extent of surface disruption and swelling. Conclusions The structural architecture of the regenerated cellulose and rice husk residues showed that they could be used for subsequent fermentation or derivation of cellulosic compounds. Therefore, ionic liquid pretreatment is an alternative in the pretreatment of lignocellulosic biomass in addition to the conventional chemical pretreatments. PMID:22958710

  11. Development of carbon dioxide adsorbent from rice husk char

    NASA Astrophysics Data System (ADS)

    Abang, S.; Janaun, J.; Anisuzzaman, S. M.; Ikhwan, F. S.

    2016-06-01

    This study was mainly concerned about the development of carbon dioxide (CO2) adsorbent from rice husk (RH). Several chemical treatments were used to produce activated rice husk char (RHAC) from RH. Initially the RH was refluxed with 3M of sodium hydroxide (NaOH) solution, activation followed by using 0.5M of zinc chloride (ZnCl2) solution and finally acidic treatment by using 0.1M of hydrochloric acid (HCl). Then, the RHAC was functionalized by using 3-chloropropylamine hydrochloride (3-CPA) and noted as RHN. RHN samples were characterized with scanning electron microscopy (SEM), mercury intrusion porosimetry (MIP), fourier transform infrared spectroscopy (FTIR). Based on the SEM, the RHN sample had a large pore diameter compared to RH sample after being treated. Based on MIP data, the average pore diameter between RH and RHAC samples were increased significantly from 0.928 microns to 1.017 microns. The RHN sample also had higher total porosity (%) compared to RHAC and RH (58.45%, 47.82% and 45.57% respectively). The total specific surface area of the sample was much increasing from RHO to RHAC (29.17 m2/g and 62.94 m2/g respectively) and slightly being decreasing from RHAC to RHN (58.88 m2/g). FTIR result showed the present of weak band at 1587 cm-1 which demonstrating of the amine group present on the sample. The CO2 capture result showed that the decreasing of operating temperature can increase the breakthrough time of CO2 capture. On the contrary decreasing of CO2 gas flow rate can increase the breakthrough time of CO2 capture. The highest total amount of CO2 adsorbed was 25338.57 mg of CO2/g of RHN sample by using 100 mL/min of gas flow rate at 30oC. Based on adsorption isotherm analysis, the Freundlich isotherm was the best isotherm to describe the CO2 adsorption on the sample.

  12. Evaluation of the occluded carbon within husk phytoliths of 35 rice cultivars

    NASA Astrophysics Data System (ADS)

    Sun, Xing; Liu, Qin; Gu, Jie; Chen, Xiang; Zhu, Keya

    2016-12-01

    Rice is a well-known silicon accumulator. During its periods of growth, a great number of phytoliths are formed by taking up silica via the plant roots. Concurrently, carbon in those phytoliths is sequestrated by a mechanism of long-term biogeochemical processes within the plant. Phytolith occluded C (PhytOC) is very stable and can be retained in soil for longer than a millennium. In this study, we evaluated the carbon biosequestration within the phytoliths produced in rice seed husks of 35 rice cultivars, with the goal of finding rice cultivars with relatively higher phytolith carbon sequestration efficiencies. The results showed that the phytolith contents ranged from 71.6 mg•g‒1 to 150.1 mg•g‒1, and the PhytOC contents ranged from 6.4 mg•g‒1 to 38.4 mg•g‒1, suggesting that there was no direct correlation between the PhytOC content and the content of rice seed husk phytoliths ( R = 0.092, p>0.05). Of all rice cultivars, six showed a higher carbon sequestration efficiency in phytolith seed husks. Additionally, the carbon biosequestration within the rice seed husk phytoliths was approximately 0.45‒3.46 kg-e-CO2•ha‒1•yr‒1. These rates indicate that rice cultivars are a potential source of carbon biosequestration which could contribute to the global carbon cycle and climate change.

  13. Characterisation of silica derived from rice husk (Muar, Johor, Malaysia) decomposition at different temperatures

    NASA Astrophysics Data System (ADS)

    Azmi, M. A.; Ismail, N. A. A.; Rizamarhaiza, M.; W. M. Hasif. A. A., K.; Taib, H.

    2016-07-01

    Rice husk was thermally decomposed to yield powder composed of silica (SiO2). Temperatures of 700°C and 1000°C were chosen as the decomposition temperatures. X-Ray Diffraction (XRD), X-Ray Florescence (XRF), Fourier Transform Infrared (FTIR), and Field Emission Scanning Electron Microscope (FESEM) analyses were conducted on a synthetic silica powder (SS-SiO2) and the rice husk ash as for the comparative characterisation study. XRD analyses clearly indicated that the decomposed rice husk yielded silica of different nature which are Crystalline Rice Husk Silica (C-RHSiO2) and Amorphous Rice Husk Silica (A-RHSiO2). Moreover, it was found that SS-SiO2 was of Quartz phase, C-RHSiO2 was of Trydimite and Cristobalite. Through XRF detection, the highest SiO2 purity was detected in SS-SiO2 followed by C-RHSiO2 and A-RHSiO2 with purity percentages of 99.60%, 82.30% and 86.30% respectively. FTIR results clearly indicated silica (SiO2) bonding 1056, 1064, 1047, 777, 790 and 798 cm-1) increased as the crystallinity silica increased. The Cristobalite phase was detected in C-RH SiO2 at the wavelength of 620 cm-1. Morphological features as observed by FESEM analyses confirmed that, SS-SiO2 and C-RH SiO2 showed prominent coarse granular morphology.

  14. Evaluation and statistical optimization of methane oxidation using rice husk amended dumpsite soil as biocover.

    PubMed

    Bajar, Somvir; Singh, Anita; Kaushik, C P; Kaushik, Anubha

    2016-07-01

    A laboratory scale study was conducted to investigate the effect of rice husk amended biocover to mitigate the CH4 emission from landfills. Various physico-chemical and environmental variables like proportion of amended biocover material (rice husk), temperature, moisture content, CH4 concentration, CO2 concentration, O2 concentration and incubation time were considered in the study which affect the CH4 bio-oxidation. For the present study, sequential statistical approach with Placket Burman Design (PBD) was used to identify significant variables, having influential role on CH4 bio-oxidation, from all variables. Further, interactive effect of four selected variables including rice husk proportion, temperature, CH4 concentration and incubation time was studied with Box-Behnken Design (BBD) adopting Response Surface Methodology (RSM) to optimize the conditions for CH4 oxidation. In this study, the maximum CH4 oxidation potential of 76.83μgCH4g(-1)dwh(-1) was observed under optimum conditions with rice husk amendment of 6% (w/w), 5h incubation time at 40°C temperature with 40% (v/v) initial CH4 concentration. The results for CH4 oxidation potential also advocated the suitability of rice husk amendment in biocover system to curb emitted CH4 from landfills/open dumpsite over conventional clay or sand cover on supplying CH4 and O2 to microbes on maintaining proper aeration.

  15. Adsorptive removal of Cd(II) from aqueous solution using natural and modified rice husk.

    PubMed

    Ye, Hengpeng; Zhu, Qing; Du, Dongyun

    2010-07-01

    In this study, the natural and modified rice husk were tested to remove Cd(II) ions from water. The modified rice husk was prepared by being treated with alkali. The results showed the Cd(II) adsorption capacity was 73.96, 125.94 mg/g, respectively, for the natural and modified rice husk. The modified rice husk had faster kinetics and higher adsorption capacities than the natural rice husk, which can be attributed to the surface structural changes of the material. Equilibrium adsorption data are more consistent with the Langmuir isotherm equation than with the Freundlich equation. The Cd(II) adsorption on the two adsorbents tends to increase with the increase of pH. The optimum pH for Cd(II) adsorption is 6.5. Both pseudo-first-order and pseudo-second-order equations were able to describe properly the kinetics of Cd(II) adsorption. The desorbability of Cd(II) is about 95.8-99.1% by 0.1M HCl solution.

  16. Strength and permeability properties of concrete containing rice husk ash with different grinding time

    NASA Astrophysics Data System (ADS)

    Jaya, Ramadhansyah Putra; Bakar, Badorul Hisham Abu; Johari, Megat Azmi Megat; Ibrahim, Mohd Haziman Wan

    2011-03-01

    The compressive concrete strength and the gas permeability properties over varying fineness of the rice husk ash were experimentally investigated. The relationships among them were analyzed. In this study eight samples made from the rice husk ashes with a different grain size were used, i.e. coarse original rice husk ash 17.96 μm (RHA0), 10.93 μm (RHA1) 9.74 μm (RHA2), 9.52 μm (RHA3), 9.34 μm (RHA4), 8.70 μm (RHA5), 6.85 μm (RHA6) and 6.65 μm (RHA7). The ordinary Portland cement was partially replaced with the rice husk ash (15 wt%). The test results showed that the RHA3 produced the concrete with good strength and low porosity. Additionally the strength of the concrete was improved due to the partial replacement of RHA3 material in comparison with normal coarse rice husk ash RHA0. On the other hand the influence of OPC and RHA materials on the concrete permeability was affected by the grinding time and age ( i.e., curing time). The permeability coefficient decreased with the increasing of curing time. The relationships between compressive strength and permeability coefficient are greatly affected by curing times and are sensitive to the grinding cementitious systems.

  17. Strength and permeability properties of concrete containing rice husk ash with different grinding time

    NASA Astrophysics Data System (ADS)

    Jaya, Ramadhansyah; Bakar, Badorul; Johari, Megat; Ibrahim, Mohd

    2011-03-01

    The compressive concrete strength and the gas permeability properties over varying fineness of the rice husk ash were experimentally investigated. The relationships among them were analyzed. In this study eight samples made from the rice husk ashes with a different grain size were used, i.e. coarse original rice husk ash 17.96 μm (RHA0), 10.93 μm (RHA1) 9.74 μm (RHA2), 9.52 μm (RHA3), 9.34 μm (RHA4), 8.70 μm (RHA5), 6.85 μm (RHA6) and 6.65 μm (RHA7). The ordinary Portland cement was partially replaced with the rice husk ash (15 wt%). The test results showed that the RHA3 produced the concrete with good strength and low porosity. Additionally the strength of the concrete was improved due to the partial replacement of RHA3 material in comparison with normal coarse rice husk ash RHA0. On the other hand the influence of OPC and RHA materials on the concrete permeability was affected by the grinding time and age (i.e., curing time). The permeability coefficient decreased with the increasing of curing time. The relationships between compressive strength and permeability coefficient are greatly affected by curing times and are sensitive to the grinding cementitious systems.

  18. Characterization of hydrogenated amorphous silicon films obtained from rice husk

    NASA Astrophysics Data System (ADS)

    Nandi, K. C.; Mukherjee, D.; Biswas, A. K.; Acharya, H. N.

    1991-08-01

    Hydrogenated amorphous silicon ( a-Si: H) films were prepared by chemical vapour deposition (CVD) of silanes generated by the acid hydrolysis of magnesium silicide (Mg 2Si) obtained from rice husk. The films were deposited at various substrate temperatures ( Ts) ranging from 430 to 520°C. The results show that the films have room temperature (294 K) dark conductivity (σ d) of the order of 10 -8 - 10 -10 (ohm-cm) -1 with single activation energy (Δ Ed) and the photoconductivity (σ ph) decreases with increase of Ts. Optical band gap ( Eopt) lies between 1.60-1.73 eV and hydrogen content ( CH) in the films is at best 8.3 at %. Au/ a-Si: H junction shows that it acts as a rectifier contact with Schottky barrier height ( VB) 0.69 eV. The films are contaminated by traces of impurities like Na, K, Al, Cl and O as revealed by secondary ion mass spectrometric (SIMS) analysis.

  19. Computational fluid dynamics modeling of rice husk combustion

    NASA Astrophysics Data System (ADS)

    Le, Kien Anh

    2017-09-01

    The combustion of rice husk fuel in a fixed bed reactor can be assumed very complicated. Researchers have studied this problem for many years. Such studies have been performed by both empirical and computational methods. However, due to the sharp increase in the development of computer science based packages, the Computational Fluid Dynamics (CFD) technique can be applied to simulate and analyse the performance of the combustion reaction. Consequently, this has saved on empirical expenditures and has additionally provided more understanding about the research objective. This paper models the computation of bed fuel combustion in a fixed bed reactor using Fluent version 12.0.16. The User Defined Functions (UDFs) were created to define the system as well as boundary conditions, and initial conditions. Furthermore, the source terms, heat exchanges and homogeneous reactions were also defined in UDFs. The species transport and volume reaction were used to model the gas phase, where the Eulerian model was employed to solve the problem using two phase modelling. The k-ɛsub-model was employed for turbulence, together with an unsteady model, as the problem was regarded as being unstable. The results obtained from the modelling work would give more understanding about the bed fuel combustion in fixed bed reactor.

  20. Catalytic pyrolysis of waste rice husk over mesoporous materials

    PubMed Central

    2012-01-01

    Catalytic fast pyrolysis of waste rice husk was carried out using pyrolysis-gas chromatography/mass spectrometry [Py-GC/MS]. Meso-MFI zeolite [Meso-MFI] was used as the catalyst. In addition, a 0.5-wt.% platinum [Pt] was ion-exchanged into Meso-MFI to examine the effect of Pt addition. Using a catalytic upgrading method, the activities of the catalysts were evaluated in terms of product composition and deoxygenation. The structure and acid site characteristics of the catalysts were analyzed by Brunauer-Emmett-Teller surface area measurement and NH3 temperature-programmed desorption analysis. Catalytic upgrading reduced the amount of oxygenates in the product vapor due to the cracking reaction of the catalysts. Levoglucosan, a polymeric oxygenate species, was completely decomposed without being detected. While the amount of heavy phenols was reduced by catalytic upgrading, the amount of light phenols was increased because of the catalytic cracking of heavy phenols into light phenols and aromatics. The amount of aromatics increased remarkably as a result of catalytic upgrading, which is attributed to the strong Brönsted acid sites and the shape selectivity of the Meso-MFI catalyst. The addition of Pt made the Meso-MFI catalyst even more active in deoxygenation and in the production of aromatics. PMID:22221540

  1. Characterization of materials formed by rice husk for construction

    NASA Astrophysics Data System (ADS)

    Portillo-Rodríguez, A. M.

    2013-11-01

    This review article delves into the use of agro-industrial wastes, which in construction field provides alternatives for environmental problems with the use of them. This fact enables development and lower costs for new options in the brick, cluster, mortar and concrete industry, what represents benefits for environment, housing and generally everything related to construction, looking for sustainability. For that reason a literature review is made to support the theme focusing on the use of rice husk in its natural, ground or ash state for manufacturing elements with clay masonry, precast and optimization of concrete and mortars. The technique used is based on scientific articles and researches found in reliable databases that were analyzed and integrated into a synthesized structure, which summarized the objectives, analysis processes, the physical and mechanical properties and finally the results. The conclusions are focused on potentiality of elements production in the construction development based on the high effectiveness like thermal insulation, low density and various benefits offered by high silica content pozzolanic properties, etc.

  2. The sorption of lead(II) ions on rice husk ash.

    PubMed

    Naiya, Tarun Kumar; Bhattacharya, Ashim Kumar; Mandal, Sailendranath; Das, Sudip Kumar

    2009-04-30

    Present study deals with the adsorption of Pb(II) from aqueous solution on rice husk ash. Rice husk is a by-product generally obtained from rice mill. Rice husk ash is a solid obtained after burning of rice husk. Batch studies were performed to evaluate the influences of various experimental parameters like pH, initial concentration, adsorbent dosage, contact time and the effect of temperature. Optimum conditions for Pb(II) removal were found to be pH 5, adsorbent dosage 5 g/L of solution and equilibrium time 1h. Adsorption of Pb(II) followed pseudo-second-order kinetics. The effective diffusion coefficient is of the order of 10(-10)m(2)/s. The equilibrium adsorption isotherm was better described by Freuindlich adsorption isotherm model. The adsorption capacity (q(max)) of rice husk ash for Pb(II) ions in terms of monolayer adsorption was 91.74 mg/g. The change of entropy (DeltaS(0)) and enthalpy (Delta H(0)) were estimated at 0.132 kJ/(mol K) and 28.923 kJ/mol respectively. The negative value of Gibbs free energy (Delta G(0)) indicates feasible and spontaneous adsorption of Pb(II) on rice husk ash. The value of the adsorption energy (E), calculated using Dubinin-Radushkevich isotherm, was 9.901 kJ/mol and it indicated that the adsorption process was chemical in nature. Application study was also carried out to find the suitability of the process in waste water treatment operation.

  3. Radon resistant potential of concrete manufactured using Ordinary Portland Cement blended with rice husk ash

    NASA Astrophysics Data System (ADS)

    Chauhan, R. P.; Kumar, Amit

    2013-12-01

    The emission of radon from building materials and soil depends upon the radium content, porosity, moisture content and radon diffusion length of materials. Several techniques have been used to reduce the radon emission from the soil using different flooring materials. But the effectiveness of radon shielding depends upon the diffusion of radon through these materials. The present study proposes a method for producing a radon resistant material for decreasing radon diffusion through it. The method involves rice husk ash (RHA) in addition to cement for the preparation of concrete used for flooring and walls. The radon diffusion, exhalation and mechanical property of concrete prepared by rice husk ash blended cement were studied. The addition of RHA caused the reduction in radon diffusion coefficient, exhalation rates, porosity and enhanced the compressive strength of concrete. The bulk radon diffusion coefficient of cementitious concrete was reduced upto 69% by addition of rice husk ash as compare to that of control concrete.

  4. Development of Indonesia corncob and rice husk biobriquette as alternative energy source

    NASA Astrophysics Data System (ADS)

    Mulyana, Cukup; Wulandari, Asry Peni; Hidayat, Darmawan; Wibawa, Bambang Mukti; Aditya Permana, P.

    2016-02-01

    Facing the increasing of fuel price and lacking of world oil resource, research for biobriquette as alternative energy for fossil fuel is conducted. Indonesia has considerable amount of biomass and it is still remain unused that can be used as biobriquette. As the initial research, Garut, Ciamis, and Sumedang district, West Java are selected which have rice husk and corncob commodities. In these disrticts, rice husk and corncob potency are respectively 4,460.73 tons and 3,222.85 tons and potentially result 57,572.86 GJ from husk and 60,911.86 GJ from corncob. To optimize mechanical properties and calorie value of biobriquette, research for calorie content and combination of rice husk and corncob are being conducted with various adhesive content and mixture. The best result of shatter index, durability, and calorie test on the corncob biobriquette is from biobriquette with 6% adhesive with calorie content as 5,516.85 kkal/kg. While the best calorie content for husk biobriquette is 6% adhesive with calorie content as 2,650.20 kkal/kg. The best calorie content for mixed biobriquette is biobriquette with 75% corncob and 25% rice husk with calorie content as 5,331.95 kkal/kg. Economy analysis show for corncob and husk biobriquette production cost per kg are respectively Rp 2,585.00 and Rp 2.625.00 with price of Rp 5,000.00 and Rp 3,000.00 obtained nett profit respectively Rp 2,173.00 and Rp 338.00.

  5. Effects of different treatments on the antioxidant properties and phenolic compounds of rice bran and rice husk.

    PubMed

    Wanyo, Pitchaporn; Meeso, Naret; Siriamornpun, Sirithon

    2014-08-15

    We investigated the changes of antioxidant activity and bioactive compounds in bran, rice husk and ground rice husk after three different treatments, namely hot-air, far-infrared radiation (FIR), and cellulase, compared with raw samples. Overall, FIR-treated group showed a higher DPPH radical scavenging activities, ferric reducing antioxidant power (FRAP), and total phenolic content (TPC) than did hot-air and cellulase treatments for all samples. A significant increase in α- and γ-tocopherols was found in FIR irradiated rice bran compared to raw bran, while α- and γ-tocopherols in hot-air and cellulase treated rice bran were remained unchanged. Cellulase significantly increased the amount of vanillic acid; however a dramatic decrease of ferulic acid was observed. The contents of γ-oryzanol in cellulase treated ground rice husk were significantly increased. Decreasing particle size in the husk was found to work positively for enhancing antioxidant activities, γ-oryzanol and phenolic compounds. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Preparation of porous bio-char and activated carbon from rice husk by leaching ash and chemical activation.

    PubMed

    Ahiduzzaman, Md; Sadrul Islam, A K M

    2016-01-01

    Preparation porous bio-char and activated carbon from rice husk char study has been conducted in this study. Rice husk char contains high amount silica that retards the porousness of bio-char. Porousness of rice husk char could be enhanced by removing the silica from char and applying heat at high temperature. Furthermore, the char is activated by using chemical activation under high temperature. In this study no inert media is used. The study is conducted at low oxygen environment by applying biomass for consuming oxygen inside reactor and double crucible method (one crucible inside another) is applied to prevent intrusion of oxygen into the char. The study results shows that porous carbon is prepared successfully without using any inert media. The adsorption capacity of material increased due to removal of silica and due to the activation with zinc chloride compared to using raw rice husk char. The surface area of porous carbon and activated carbon are found to be 28, 331 and 645 m(2) g(-1) for raw rice husk char, silica removed rice husk char and zinc chloride activated rice husk char, respectively. It is concluded from this study that porous bio-char and activated carbon could be prepared in normal environmental conditions instead of inert media. This study shows a method and possibility of activated carbon from agro-waste, and it could be scaled up for commercial production.

  7. Genetic analysis of grain shape and weight after cutting rice husk.

    PubMed

    Fu, J R; Zhu, L X; Sun, X T; Zhou, D H; Ouyang, L J; Bian, J M; He, H H; Xu, J

    2015-12-22

    Grain shape and weight are the most important components of rice yield and are controlled by quantitative trait loci (QTLs). In this study, a double-haploid population, derived from the cross of japonica CJ06 and indica TN1, was used to analyze QTLs for grain shape and weight under two conditions: normal growth with unbroken husk and removing partial husk after flowering. Correlation analysis revealed that these traits, except grain weight, had a connection between the two conditions. Twenty-nine QTLs for grain shape and weight were detected on chromosomes 1 to 3; 6; 8 to 10; and 12, with the likelihood of odds value ranging from 2.38 to 5.36, including 10 different intervals. Some intervals were specifically detected after removing partial husk. The results contribute to the understanding of the genetic basis of grain filling and growth regulation, and provide us some assistance for improving grain plumpness in rice breeding.

  8. Improved production of reducing sugars from rice husk and rice straw using bacterial cellulase and xylanase activated with hydroxyapatite nanoparticles.

    PubMed

    Dutta, Nalok; Mukhopadhyay, Arka; Dasgupta, Anjan Kr; Chakrabarti, Krishanu

    2014-02-01

    Purified bacterial cellulase and xylanase were activated in the presence of calcium hydroxyapatite nanoparticles (NP) with concomitant increase in thermostability about 35% increment in production of d-xylose and reducing sugars from rice husk and rice straw was obtained at 80°C by the sequential treatment of xylanase and cellulase enzymes in the presence of NP compared to the untreated enzyme sets. Our findings suggested that if the rice husk and the rice straw samples were pre-treated with xylanase prior to treatment with cellulase, the percentage increase of reducing sugar per 100g of substrate (starting material) was enhanced by about 29% and 41%, respectively. These findings can be utilized for the extraction of reducing sugars from cellulose and xylan containing waste material. The purely enzymatic extraction procedure can be substituted for the harsh and bio-adverse chemical methods.

  9. Synthesis of silica nanoparticles from Vietnamese rice husk by sol–gel method

    PubMed Central

    2013-01-01

    Silica powder at nanoscale was obtained by heat treatment of Vietnamese rice husk following the sol–gel method. The rice husk ash (RHA) is synthesized using rice husk which was thermally treated at optimal condition at 600°C for 4 h. The silica from RHA was extracted using sodium hydroxide solution to produce a sodium silicate solution and then precipitated by adding H2SO4 at pH = 4 in the mixture of water/butanol with cationic presence. In order to identify the optimal condition for producing the homogenous silica nanoparticles, the effects of surfactant surface coverage, aging temperature, and aging time were investigated. By analysis of X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, the silica product obtained was amorphous and the uniformity of the nanosized sample was observed at an average size of 3 nm, and the BET result showed that the highest specific surface of the sample was about 340 m2/g. The results obtained in the mentioned method prove that the rice husk from agricultural wastes can be used for the production of silica nanoparticles. PMID:23388152

  10. Consecutively Preparing D-Xylose, Organosolv Lignin, and Amorphous Ultrafine Silica from Rice Husk

    PubMed Central

    Zhang, Hongxi; Ding, Xuefeng; Wang, Zichen; Zhao, Xu

    2014-01-01

    Rice husk is an abundant agricultural by-product reaching the output of 80 million tons annually in the world. The most common treatment method of rice husk is burning or burying, which caused serious air pollution and resource waste. In order to solve this problem, a new method is proposed to comprehensively utilize the rice husk in this paper. Firstly, the D-xylose was prepared from the semicellulose via dilute acid hydrolysis. Secondly, the lignin was separated via organic solvent pulping from the residue. Finally, the amorphous ultrafine silica was prepared via pyrolysis of the residue produced in the second process. In this way, the three main contents of rice husk (semicellulose, lignin, and silica) are consecutively converted to three fine chemicals, without solid waste produced. The yields of D-xylose and organosolv lignin reach 58.2% and 58.5%, respectively. The purity and specific surface of amorphous ultrafine silica reach 99.92% and 225.20 m2/g. PMID:25140120

  11. Synthesis of silica nanoparticles from Vietnamese rice husk by sol-gel method

    NASA Astrophysics Data System (ADS)

    Le, Van Hai; Thuc, Chi Nhan Ha; Thuc, Huy Ha

    2013-02-01

    Silica powder at nanoscale was obtained by heat treatment of Vietnamese rice husk following the sol-gel method. The rice husk ash (RHA) is synthesized using rice husk which was thermally treated at optimal condition at 600°C for 4 h. The silica from RHA was extracted using sodium hydroxide solution to produce a sodium silicate solution and then precipitated by adding H2SO4 at pH = 4 in the mixture of water/butanol with cationic presence. In order to identify the optimal condition for producing the homogenous silica nanoparticles, the effects of surfactant surface coverage, aging temperature, and aging time were investigated. By analysis of X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, the silica product obtained was amorphous and the uniformity of the nanosized sample was observed at an average size of 3 nm, and the BET result showed that the highest specific surface of the sample was about 340 m2/g. The results obtained in the mentioned method prove that the rice husk from agricultural wastes can be used for the production of silica nanoparticles.

  12. Pantoea ananatis as a Cause of Corneal Infiltrate after Rice Husk Injury

    PubMed Central

    Manoharan, Geetha; Jeganathan, Lakshmi Priya; DSilva, Sean Socrates; Prajna, N. Venkatesh

    2012-01-01

    We report a case of an agricultural worker presenting with corneal infiltrate following ocular injury with a rice husk. On examination, a superficial corneal foreign body was removed and sent for culture, which grew Pantoea ananatis. This is, to our knowledge, the first clinical case report of Pantoea ananatis causing corneal infiltrate. PMID:22461671

  13. Consecutively preparing d-xylose, organosolv lignin, and amorphous ultrafine silica from rice husk.

    PubMed

    Zhang, Hongxi; Ding, Xuefeng; Wang, Zichen; Zhao, Xu

    2014-01-01

    Rice husk is an abundant agricultural by-product reaching the output of 80 million tons annually in the world. The most common treatment method of rice husk is burning or burying, which caused serious air pollution and resource waste. In order to solve this problem, a new method is proposed to comprehensively utilize the rice husk in this paper. Firstly, the D-xylose was prepared from the semicellulose via dilute acid hydrolysis. Secondly, the lignin was separated via organic solvent pulping from the residue. Finally, the amorphous ultrafine silica was prepared via pyrolysis of the residue produced in the second process. In this way, the three main contents of rice husk (semicellulose, lignin, and silica) are consecutively converted to three fine chemicals, without solid waste produced. The yields of D-xylose and organosolv lignin reach 58.2% and 58.5%, respectively. The purity and specific surface of amorphous ultrafine silica reach 99.92% and 225.20 m(2)/g.

  14. Physical properties and pyrolysis characteristics of rice husks in different atmosphere

    NASA Astrophysics Data System (ADS)

    Wang, Xinsheng; Lu, Zhenlin; Jia, Lei; Chen, Jiangxian

    This paper explores the physical properties and pyrolysis characteristics of rice husk combustion in air and in argon. The SEM results show that the outer epidermis of combusted RHIR (rice husk in air) is well organized with features that include papillae shapes and full, straight, high ridges. The inner epidermis of the RHIR has long rectangular furrow tissues. The results also show that the outer epidermis of pyrolyzed RHR (rice husk in argon) has ridges that are not as straight as for the RHIR and the top of the papillae have small holes. The inner surface of the RHR looks a some cracked. XPS analysis shows that the surfaces of RHIR and RHR contain carbon, oxygen, and silicon. The carbon was found to be in the elemental graphite form, the oxygen in the -2 oxidation state, and the silicon in the Si4+ form as SiO2. The DSC graphs have ;camel peaks;, showing that an increase in rate of heating leads to an increase in the exothermic peaks. Calculations show that, initially, increased temperature leads to increased activation energy for pyrolysis, but as the temperature continues to increase, the activation energy decreases again. The frequency factor follows the same trend. In analysis of carbon content, rice husk volatile carbon content is the largest, it is about 33.94%, especially 700 °C, the carbon content of volatile minimum is about 0.33%.

  15. Heavy metals removal from wastewaters using organic solid waste-rice husk.

    PubMed

    Sobhanardakani, S; Parvizimosaed, H; Olyaie, E

    2013-08-01

    In this study, the removal of Cr(III) and Cu(II) from contaminated wastewaters by rice husk, as an organic solid waste, was investigated. Experiments were performed to investigate the influence of wastewater initial concentration, pH of solution, and contact time on the efficiency of Cr(III) and Cu(II) removal. The results indicated that the maximum removal of Cr(III) and Cu(II) occurred at pH 5-6 by rice husk and removal rate increased by increased pH from 1 to 6. It could be concluded that the removal efficiency was enhanced by increasing wastewater initial concentration in the first percentage of adsorption and then decreased due to saturation of rice husk particles. Also according to achieved results, calculated saturation capacity in per gram rice husk for Cr(III) and Cu(II) were 30 and 22.5 mg g(-1), respectively. The amounts of Cr(III) and Cu(II) adsorbed increased with increase in their contact time. The rate of reaction was fast. So that 15-20 min after the start of the reaction, between 50 and 60 % of metal ions were removed. Finally, contact time of 60 min as the optimum contact time was proposed.

  16. Structural characterization and antioxidant activity evaluation of lignins from rice husk.

    PubMed

    Salanti, Anika; Zoia, Luca; Orlandi, Marco; Zanini, Fabiana; Elegir, Graziano

    2010-09-22

    In recent years, lignin and extractives from herbaceous plants and crops are receiving increasing attention for their renewability and large annual biomass stock. It is worth noting that only a few studies deal with the chemical characterization of rice husk, a side product of one of the most important crops with regard to human nutrition. Thus, in this study lignin from rice husk was isolated and characterized. Two different extraction procedures were optimized and tested: acidolysis and alkaline enzymatic (AE). The different lignins isolated were fully characterized by means of gravimetric, chromatographic (GPC), and spectroscopic (31P NMR, 2D-HSQC-NMR) analyses with the aim to compare yields, sample purity, and chemical properties, recognized as key parameters for future development. Notwithstanding the extraction procedure, the results highlighted that rice husk lignin is mainly formed by guaiacyl and p-hydroxyphenyl units. The acidolytic approach showed an appreciable lignin recovery and high purity, whereas the AE lignin sample was found to be rich in residual polysaccharides and oxidized functionalities. Moreover, different rice husk extracts, along with acidolysis lignin and AE lignin specimens, were assayed for their antioxidant activity by means of a DPPH radical scavenging test.

  17. Characterisation of silica derived from rice husk (Muar, Johor, Malaysia) decomposition at different temperatures

    SciTech Connect

    Azmi, M. A.; Ismail, N. A. A.; Rizamarhaiza, M.; Hasif, W. M. K. A. A.; Taib, H.

    2016-07-19

    Rice husk was thermally decomposed to yield powder composed of silica (SiO{sub 2}). Temperatures of 700°C and 1000°C were chosen as the decomposition temperatures. X-Ray Diffraction (XRD), X-Ray Florescence (XRF), Fourier Transform Infrared (FTIR), and Field Emission Scanning Electron Microscope (FESEM) analyses were conducted on a synthetic silica powder (SS-SiO{sub 2}) and the rice husk ash as for the comparative characterisation study. XRD analyses clearly indicated that the decomposed rice husk yielded silica of different nature which are Crystalline Rice Husk Silica (C-RHSiO{sub 2}) and Amorphous Rice Husk Silica (A-RHSiO{sub 2}). Moreover, it was found that SS-SiO{sub 2} was of Quartz phase, C-RHSiO{sub 2} was of Trydimite and Cristobalite. Through XRF detection, the highest SiO{sub 2} purity was detected in SS-SiO{sub 2} followed by C-RHSiO{sub 2} and A-RHSiO{sub 2} with purity percentages of 99.60%, 82.30% and 86.30% respectively. FTIR results clearly indicated silica (SiO{sub 2}) bonding 1056, 1064, 1047, 777, 790 and 798 cm{sup −1}) increased as the crystallinity silica increased. The Cristobalite phase was detected in C-RH SiO{sub 2} at the wavelength of 620 cm{sup −1}. Morphological features as observed by FESEM analyses confirmed that, SS-SiO{sub 2} and C-RH SiO{sub 2} showed prominent coarse granular morphology.

  18. Kinetics of the thermal degradation of rice husks in nitrogen atmosphere

    SciTech Connect

    Mansaray, K.G.; Ghaly, A.E.

    1999-11-01

    The use of agricultural residues for power production has generated increasing interest in the conversion of rice husks to higher quality fuels by thermochemical conversion processes such as pyrolysis, combustion, and gasification. However, the reliable design and operation of thermochemical conversion systems requires considerable knowledge of rice husk thermal degradation characteristics of kinetics. The thrust of this paper therefore was to study the reaction kinetics of four varieties of rice husk at a heating rate of 20 C min{sup {minus}1} in an inert atmosphere of pure nitrogen (99.5% nitrogen, 0.5% oxygen) using thermogravimetric analysis and derivative thermogravimetric techniques. The thermal degradation characteristics and the kinetic parameters (activation energy, preexponential factor, and order of reaction) were determined for the two prominent reaction zones from the thermogravimetric curves. Thermal degradation rates in the first reaction zone were relatively higher than those in the second reaction zone. The initial degradation temperatures were 220, 232, 223, and 240 C for the rice husk varieties Lemont LG, ROK 14, CP 4, and Pa Potho, respectively. Residual weights recorded at 700 C were in the range of 33.9--38.7%. Higher activation energies (29.0--35.4 kJ/mol) and preexponential factors (4.7 {times} 10{sup 3} to 6.4 {times} 10{sup 4} min{sup {minus}1}) were obtained for all rice husk varieties in the first reaction zone as compared to those of the second reaction zone (15.1---17.7 kJ/mol and 1.0 {times} 10{sup 2} to 5.1 {times} 10{sup 2} min{sup {minus}1} for the activation energy and preexponential factor, respectively). The order of reactions was in the range of 0.90--1.08 for the first reaction zone and 0.30--0.36 for the second reaction zone.

  19. Mechanical characterization of filler sandcretes with rice husk ash additions. Study applied to Senegal

    SciTech Connect

    Cisse, I.K.; Laquerbe, M.

    2000-01-01

    To capitalize on the local materials of Senegal (agricultural and industrial wastes, residual fines from crushing process, sands from dunes, etc.), rise husk ash and residues of industrial and agricultural wastes have been used as additions in sandcretes. The mechanical resistance of sandcrete blocks obtained when unground ash (and notably the ground ash) is added reveals that there is an increase in performance over the classic mortar blocks. In addition, the use of unground rice husk ash enables production of a lightweight sandcrete with insulating properties, at a reduced cost. The ash pozzolanic reactivity explains the high strengths obtained.

  20. Utilization of rice husk ash as novel adsorbent: a judicious recycling of the colloidal agricultural waste.

    PubMed

    Foo, K Y; Hameed, B H

    2009-11-30

    Concern about environmental protection has aroused over the years from a global viewpoint. To date, the ever-increasing importance of biomass as the energy and material resources has lately been accounted by the rising prices for the crude petroleum oil. Rice husk ash, the most appropriate representative of the high ash biomass waste, is currently obtaining sufficient attraction, owning to its wide usefulness and potentiality in environmental conservation. Confirming the assertion, this paper presents a state of the art review of the rice milling industry, its background studies, fundamental properties and industrial applications. Moreover, the key advance on the preparation of novel adsorbents, its major challenges together with the future expectation has been highlighted and discussed. Conclusively, the expanding of rice husk ash in the field of adsorption science represents a viable and powerful tool, leading to the superior improvement of pollution control and environmental preservation.

  1. A study on flexural and water absorption of surface modified rice husk flour/E-glass/polypropylene hybrid composite

    NASA Astrophysics Data System (ADS)

    Rassiah, K.; Sin, T. W.; Ismail, M. Z.

    2016-10-01

    This work is to study the effects of rice husk (RH)/E-Glass (EG)/polypropylene (PP) hybrid composites in terms of flexural and water absorption properties. The tests conducted are the flexural test and also the water absorption test using two types of water: distilled and sea water. The hybrid composites are prepared with various ratios of fibre weight fractions and the rice husk is treated using 2% Sodium Hydroxide (NaOH) to improve interaction and adhesion between the non-polar matrix and the polar lignocellulosic fibres. It was found that the content of rice husk/E-Glass fillers affected the structural integrity and flexural properties of hybrid composites. In addition, a higher ratio of rice husk contributes to higher water absorption in the hybrid composites.

  2. Characterization of silica distribution in rice husk using Synchrotron Radiation µCT and its implications for archaeological interpretation.

    PubMed

    Wu, Yan; Yang, Yimin; Xiao, Tiqiao; Gu, Zhou; Hill, David V; Wang, Changsui

    2014-10-01

    This article reports the results of a pilot project using Synchrotron Radiation µCT (computer-aided tomography) to examine the distribution of silica within phytoliths from rice husks. Experiments indicate that computed tomography can be used to show how silica accumulates and is distributed in a distinctive zigzag pattern of long epidermal cells that are characteristic of phytoliths from rice husks. This method will help us to understand why the dry ashing method produced much more zigzag pattern of long cells phytoliths from rice husk than did the acid extraction method. Besides, the zigzag morphological pattern exhibited by long epidermal cells is characteristic of this species which makes it useful in the identification of rice husks from archaeological contexts and indicating heating process. © 2014 Wiley Periodicals, Inc.

  3. Development of briquette fuel from cashew shells and rice husk mixture

    NASA Astrophysics Data System (ADS)

    Yohana, Eflita; Arijanto, Kalyana, Ivan Edgar; Lazuardi, Andy

    2017-01-01

    In Indonesia, a large amount of biomasses are available from cashew plantations and rice fields and constitute one of the raw material sources for thermal energy. Annually, 130.052 tons of whole cashews can produce cashew shells with a total energy content of 4,933x109 kcal. In addition, 49 million tons of rice is produced annually in Indonesia. From this sum, 7.5-10 million tons of rice husks are obtained with a total energy content of 2.64x1013 kcal. The purpose of this research is to review the briquette of biomass made from a mixture of cashew shells and rice husks with polyvinyl acetate (PVA) as the adhesive. The mixture ratio of cashew shells and rice husks is varied with a range of 75:25, 50:50, and 25:75 % weight. Briquettes are made in a cylinder mold and pressed using a hydraulic press machine. The pressing pressure varies from 2.500, 5.000, and 7.500 kg/m2. Results show that a briquette with a mixture ratio of 75:25 % shows good pressure tenacity. A model is used to relate density with briquetting pressure. This model shows that the briquette has low compressibility at 0.13. Enhancement of the heating value for the briquettes is also carried out using the torrefaction treatment. The torrefaction process produces biomass briquettes made from a mixture of cashew shells and rice husks with a heating value on par to sub-bituminous coal according to the ASTM D 388 standard classification with a heating value of 6.712 kcal/kg.

  4. Adsorptive removal of Zn(II) ion from aqueous solution using rice husk-based activated carbon

    NASA Astrophysics Data System (ADS)

    Taha, Mohd F.; Ibrahim, Muhammad H. C.; Shaharun, Maizatul S.; Chong, F. K.

    2012-09-01

    The study of rice husk-based activated carbon as a potential low-cost adsorbent for the removal of Zn(II) ion from aqueous solution was investigated. Rice husk, an agricultural waste, is a good alternative source for cheap precursor of activated carbon due to its abundance and constant availability. In this work, rice husk-based activated carbon was prepared via chemical treatment using NaOH as an activation agent prior the carbonization process. Three samples, i.e. raw rice husk, rice husk treated with NaOH and rice husk-based activated carbon carbonized at 650°C, were analyzed for their morphological characteristics using field-emission scanning electron microscope/energy dispersive X-ray (FESEM/EDX). Other analyses were also conducted on these samples using fourier transmitter infrared spectroscopy (FTIR), CHN elemental analyzer and X-ray diffraction (XRD) for characterization study. The porous properties of rice husk-based activated carbon were determined by Brunauer-Emmett-Teller (BET) surface area analyzer, and its surface area and pore volume were found to be 255 m2/g and 0.17 cm2/g, respectively. The adsorption studies for the removal of Zn(II) ion from aqueous solution were carried out as a function of varied contact time at room temperature. The concentration of Zn(II) ion was analyzed using atomic absorption spectrophotometer (AAS). The results obtained from adsorption studies indicate the potential of rice husk as an economically promising precursor for the preparation of activated carbon for removal of Zn(II) ion from aqueous solution.

  5. Characterization of H3PO4-Treated Rice Husk Adsorbent and Adsorption of Copper(II) from Aqueous Solution

    PubMed Central

    Zheng, Ru; Zhao, Jiaying; Ma, Fang; Zhang, Yingchao; Meng, Qingjuan

    2014-01-01

    Rice husk, a surplus agricultural byproduct, was applied to the sorption of copper from aqueous solutions. Chemical modifications by treating rice husk with H3PO4 increased the sorption ability of rice husk for Cu(II). This work investigated the sorption characteristics for Cu(II) and examined the optimum conditions of the sorption processes. The elemental compositions of native rice husk and H3PO4-treated rice husk were determined by X-ray fluorescence (XRF) analysis. The scanning electron microscopic (SEM) analysis was carried out for structural and morphological characteristics of H3PO4-treated rice husk. The surface functional groups (i.e., carbonyl, carboxyl, and hydroxyl) of adsorbent were examined by Fourier Transform Infrared Technique (FT-IR) and contributed to the adsorption for Cu(II). Adsorption isotherm experiments were carried out at room temperature and the data obtained from batch studies fitted well with the Langmuir and Freundlich models with R2 of 0.999 and 0.9303, respectively. The maximum sorption amount was 17.0358 mg/g at a dosage of 2 g/L after 180 min. The results showed that optimum pH was attained at pH 4.0. The equilibrium data was well represented by the pseudo-second-order kinetics. The percentage removal for Cu(II) approached equilibrium at 180 min with 88.9% removal. PMID:24678507

  6. Use of bean husk as an easily digestible fiber source for activating the fibrolytic rumen bacterium Fibrobacter succinogenes and rice straw digestion.

    PubMed

    Fuma, Ryosuke; Oyaizu, Shinya; Nukui, Yoko; Ngwe, Tin; Shinkai, Takumi; Koike, Satoshi; Kobayashi, Yasuo

    2012-10-01

    A series of in sacco and in vitro studies were carried out to evaluate bean husks for activation of fibrolytic rumen bacteria and rice straw digestion. First, lablab bean husk, chickpea husk and rice straw were suspended in the rumen of sheep to analyze the bacterial consortium developed on each fiber source. Known members of fiber-associating bacteria were found on both lablab bean husk and rice straw, but some of these bacteria were lacking on chickpea husk. Second, a pure culture study was carried out using six strains of Fibrobacter succinogenes. Both husks stimulated the growth of all tested strains, including a strain that did not grow on rice straw. The strain OS128 that showed the highest growth on rice straw displayed even higher growth on lablab bean husk without a time lag. Finally, two-step incubations were carried out to determine whether prior incubation of rumen fluid with husks stimulates subsequent rice straw digestion. Higher digestibility of rice straw was recorded in the second-round incubation following the first incubation with bean husks. These results suggest that the tested bean husks improve the digestion of rice straw by activating fibrolytic F. succinogenes and other associated bacteria.

  7. Determination of reaction kinetics of rice husks in air using thermogravimetric analysis

    SciTech Connect

    Mansaray, K.G.; Ghaly, A.E.

    1999-12-01

    Rice husk is produced in large quantities as a by-product of rice milling in rice-producing countries and has posed disposal problems in these countries. Disposal of or energy recovery from rice husk can be accomplished by thermochemical conversion processes (pyrolysis, combustion, and gasification). However, it appears that the kinetics of rice husk, which can contribute to the accurate modeling and design of thermochemical conversion processes, have not been studied extensively. In this paper the technique of thermogravimetric analysis (TGA) was used to study the thermochemical behavior of four varieties of rice husk (Lemont LG, ROK 14, CP 4, and Pa Potho). The thermal degradation of rice husk was studied in an air atmosphere (21% oxygen and 79% nitrogen) from ambient temperature to 700 C at the heating rate of 20 C/min. The thermograms showed two distinct reaction zones. The kinetic parameters (activation energy, preexponential factor, and order of reaction) were determined for the two reaction zones by applying thermoanalytical techniques to the reaction kinetics. Higher thermal degradation rates were observed in the first reaction zone due to rapid release of volatiles as compared to those in the second reaction zone. In the first reaction zone the activation energies ranged from 37.0 to 54.7 kJ/mol. Relatively lower activation energies (18.0--21.0 kJ/mol) were obtained in the second reaction zone. The preexponential factors were in the range of 4.3 x 10{sup 4} to 6.4 x 10{sup 6} min{sup {minus}1} in the first reaction zone and 4.5 x 10{sup 2} to 1.5 x 10{sup 3} min{sup {minus}1} in the second reaction zone. The orders of reaction were in the range of 1.2--1.6 and 0.4--0.5 for the first and second reaction zones, respectively. The predicted thermal degradations were in good agreement with the experimental data in both the first and second reaction zones.

  8. Fabrication and Characterization of Carbonized Rice Husk/Barium Titanate Nanocomposites

    NASA Astrophysics Data System (ADS)

    Melvin, G. J. H.; Wang, Z.; Ni, Q.-Q.; Siambun, N. J.; Rahman, M. M.

    2017-09-01

    Carbon materials were prepared by carbonizing rice husk (RHs) at 2500°C. Few- and multi-layer graphene were obtained from this carbonization process. Barium titanate (BTO) nanoparticles were fabricated by using sol-gel method. Then, the BTO nanoparticles were grafted onto the surface of carbonized rice husk (CRH) to fabricate CRH/BTO nanocomposites. The nanocomposites were characterized using scanning transmission electron microscopy (STEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman measurement, and X-ray photoelectron spectroscopy (XPS). Based on the broadening of (1 1 0) peak from XRD result, the average crystalline size of BTO nanoparticles were calculated to be 16.5 nm. Coexistence of cubic and tetragonal phase of BTO nanoparticles is expected, based on the XRD and Raman results. From XPS result, carbon, barium, titanium, and oxygen peaks were also observed. The combination of CRH with BTO can integrate the properties of these two components to form nanocomposites for broad applications.

  9. Influence of roasting-quenching pretreatment on the rice husk silica prepared by calcination method

    NASA Astrophysics Data System (ADS)

    Maksum, Ahmad; Rustandi, Andi; Permana, Sulaksana; Soedarsono, Johny Wahyuadi

    2017-03-01

    Calcination is a simple method to produce silica from rice husk (RH). One of the key to obtain higher purity silica from rice husk by calcination method is the effectiveness of impurities removal, especially potassium, from RH surface before calcination process. So, in the present study, an attempt has been made to produce high purity silica powder by using calcination method with the combination of roasting-quenching and acid leaching as a pretreatment to eliminate metal impurities, especially potassium, detected by using inductively coupled plasma mass spectrometry (ICP-MS). Finally, the high purity silica, 99.928% was obtained by roasting and calcination temperature of 300°C and 650°C, respectively. However, by considering less energy usage and silica purity achievement, the combination of 300°C roasting-quenching, 1M hydrochloric acid leaching, and calcination at the temperature of 600°C was the best route.

  10. Probiotic activity of lignocellulosic enzyme as bioactivator for rice husk degradation

    NASA Astrophysics Data System (ADS)

    Lamid, Mirni; Al-Arif, Anam; Warsito, Sunaryo Hadi

    2017-02-01

    The utilization of lignocellulosic enzyme will increase nutritional value of rice husk. Cellulase consists of C1 (β-1, 4-glucan cellobiohydrolase or exo-β-1,4glucanase), Cc (endo-β-1,4-glucanase) and component and cellobiose (β-glucocidase). Hemicellulase enzyme consists of endo-β-1,4-xilanase, β-xilosidase, α-L arabinofuranosidase, α-D-glukuronidaseand asetil xilan esterase. This research aimed to study the activity of lignocellulosic enzyme, produced by cows in their rumen, which can be used as a bioactivator in rice husk degradation. This research resulted G6 and G7 bacteria, producing xylanase and cellulase with the activity of 0.004 U mL-1 and 0.021 U mL-1; 0.003 ( U mL-1) and 0.026 (U mL-1) respectively.

  11. Utilization of rice-husk and coconut shell carbons for water disinfection.

    PubMed

    Carmalin Sophia, A; Catherine, D; Bhalambaal, V M

    2013-01-01

    In the present study, experiments were conducted to investigate the feasibility of using carbon derived from rice husk and coconut shell for the decontamination of water containing Escherichia coli (E. coli). The effects of silver impregnation on these agro-waste carbons were also investigated. All the carbons showed >99% removal of E coli. Among the four carbons studied, rice husk based carbon (RHC) showed better removal than the other carbons investigated. However, silver impregnated carbons showed only marginal increase in the decontamination experiments. SEM and BET results reveal that the carbons were mesoporous in nature. FTIR shows the presence of functional groups viz. C=O and -OH that might be responsible.for adsorption of E. coli on the carbon.

  12. Formation of Nanodimensional 3C-SiC Structures from Rice Husks

    NASA Astrophysics Data System (ADS)

    Gorzkowski, E. P.; Qadri, S. B.; Rath, B. B.; Goswami, R.; Caldwell, J. D.

    2013-05-01

    We have demonstrated that large quantities of β-SiC nanostructures can be obtained from rice husk agricultural waste by using controlled conditions in a thermogravimetric setup. This simple and inexpensive method of producing these structures on a large scale is critical for applications in nanoelectronics, nanosensors, and biotechnology. The temperature and atmosphere are two critical elements in forming either α-cristobalite (SiO2) or β-SiC. Using different characterization methods (x-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy), we have shown that pyrolysis of rice husks in argon atmosphere at 1375°C results in simultaneous formation of carbon nanotubes, β-SiC nanowires/nanorods, and β-SiC powder.

  13. Fixed-bed column study for Cu2+ removal from solution using expanding rice husk.

    PubMed

    Luo, Xuegang; Deng, Zaifang; Lin, Xiaoyan; Zhang, Chi

    2011-03-15

    This paper deals with removal of copper ions from solution by raw rice husk (RRH) and expanding rice husk (ERH). Different column design parameters like bed depth, flow rate and initial copper concentration were investigated. It was found that the equilibrium uptake (q(eq(exp))) of the ERH and RRH increased with increase in initial copper concentration but decreased with increase in flow rate and bed depth, respectively. The higher adsorption capacity and longer breakthrough time were observed for ERH in comparison with RRH, under the same conditions. Compared to coconut-shell activated carbon (C-AC), ERH was also found more effective in removing Cu(2+). 0.01 mol L(-1) HCl solution was used for desorption of column which was prior to absorb copper ion, and 0.01 mol L(-1) NaOH solution was used for re-activation. Column regeneration and reuse studies were conducted for adsorption-desorption cycle.

  14. Synthesis and characterization of cellulose acetate from rice husk: eco-friendly condition.

    PubMed

    Das, Archana M; Ali, Abdul A; Hazarika, Manash P

    2014-11-04

    Cellulose acetate was synthesized from rice husk by using a simple, efficient, cost-effective and solvent-free method. Cellulose was isolated from rice husk (RH) using standard pretreatment method with dilute alkaline and acid solutions and bleaching with 2% H2O2. Cellulose acetate (CA) was synthesized successfully with the yield of 66% in presence of acetic anhydride and iodine as a catalyst in eco-friendly solvent-free conditions. The reaction parameters were standardized at 80 °C for 300 min and the optimum results were taken for further study. The extent of acetylation was evaluated from % yield and the degree of substitution (DS), which was determined by (1)H NMR and titrimetrically. The synthesized products were characterized with the help modern analytical techniques like FT-IR, (1)H NMR, XRD, etc. and the thermal behavior was evaluated by TGA and DSC thermograms.

  15. Physical characteristics of chitosan-silica composite of rice husk ash

    NASA Astrophysics Data System (ADS)

    Sumarni, Woro; Sri Iswari, Retno; Marwoto, Putut; Rahayu, Endah F.

    2016-02-01

    Some previous studies showed that the characteristics of chitosan membranes have a very rigid and non-porous structure so that its utilization is not maximized, particularly in the filtration process. Hence, it needs modification to improve the quality of the chitosan membranes. Adding the silica into the chitosan membranes is one of the offered solutions to overcome the problems of physical and mechanical properties of chitosan. This study aims to investigate the effect of variations in the silica composition to the physical characteristics of the chitosan-silica membranes of rice husk ash that were synthesized. The chitosan used is derived from the chitin of Vannamei shrimps’ shell with 82% degree of de-acetylation, while the silica was synthesized from rice husk ash with rendering of silica (SiO2) by 5% and the results of XRD analysis showed an amorphous phase. Membrane synthesis was performed using the phase inversion method with chitosan-silica mass ratios of rice husk ash, which were 1:0.0; 1:0.5; 1:1.0; 1:1.5 and 1:2.0. The results showed that the addition of silica increases the swelling index and the membrane permeability. The results of the analysis, FTIR spectra, obtained a new functional group after the addition of silica, they are Si-OH, Si-O-Si, and CO- NH2. The morphology test using CCD Microscope MS-804 results in the very tight chitosan membranes without the silica surface, it has no pores, smooth and homogeneous, while the chitosan-silica composite membrane of rice husk ash obviously has cracks and small cavities that seemed to spread out.

  16. The study of ionizing radiation effects on polypropylene and rice husk ash composite

    NASA Astrophysics Data System (ADS)

    Alfaro, E. F.; Dias, D. B.; Silva, L. G. A.

    2013-03-01

    The aim of this work was to study the ionizing radiation effects on polypropylene/20% of rice husk ash composites. The composites were irradiated by electron beam at different doses and the mechanical and thermal properties were evaluated using tensile strength, Izod impact, hardness, softening temperature, differential scanning calorimetry (DSC) and thermogravimetry (TG). The results showed that the properties decreased by increasing irradiation dose due to chain scission.

  17. Effect of leaching with 5-6 N H2SO4 on thermal kinetics of rice husk during pure silica recovery.

    PubMed

    Ali, Muhammad; Ul Haq, Ehsan; Abdul Karim, Muhammad R; Ahmed, Sajjad; Ibrahim, Ather; Ahmad, Waheed; Baig, Waqas M

    2016-01-01

    Rice husk is a potential source for renewable energy and silica. To extract the maximum amount of silica, usually the rice husk is treated with strong acids that burn the organic part leaving behind a black residue. In this research, sulfuric acid is used as an oxidizing agent. Efforts are focused to find out more about the behavior of acid-treated rice husk by using thermal exposure, and results are compared with results for raw rice husk which is thermally exposed but not acid treated. Reaction ratio of rice husk combustion and energy of activation were calculated using the thermogravimetric data. Acid treatment was found influential in initiating degradation earlier compared to raw husk and an overall increase in value of activation energy was observed when heating rate was increased.

  18. Lignin isolation process from rice husk by alkaline hydrogen peroxide: Lignin and silica extracted

    NASA Astrophysics Data System (ADS)

    Ma'ruf, Anwar; Pramudono, Bambang; Aryanti, Nita

    2017-03-01

    Biomass is one of abundance resources in the world. Biomass consists of three main materials such as cellulose, hemicelluloses and lignin. Therefore, biomass can be referred to lignocellulosic material. Both the cellulose and hemicelluloses fractions are polymers of sugars, and thereby a potential source of fermentable sugars, or other processes that convert sugars into products. Lignin is a polymer compound which contains of phenolic compounds. Rice husk is one of biomass, which has high contain of lignin. Rice husk has special characteristics because of silica content. The aim of this paper is to analyze lignin and silica extracted during lignin isolation process of rice husk using alkaline hydrogen peroxide. Three main variables such as solvent/solid ratio, concentration of hydrogen peroxide and pH of the mixture are studied. The optimum conditions for lignin isolation are at solvent/solid ratio 9:1 ml/gr, hydrogen peroxide concentration of 1.5%v and pH of the mixture of 11.

  19. Fungus-mediated biotransformation of amorphous silica in rice husk to nanocrystalline silica.

    PubMed

    Bansal, Vipul; Ahmad, Absar; Sastry, Murali

    2006-11-01

    Rice husk is a cheap agro-based waste material, which harbors a substantial amount of silica in the form of amorphous hydrated silica grains. However, there have been no attempts at harnessing the enormous amount of amorphous silica present in rice husk and its room-temperature biotransformation into crystalline silica nanoparticles. In this study, we address this issue and describe how naturally deposited amorphous biosilica in rice husk can be bioleached and simultaneously biotransformed into high value crystalline silica nanoparticles. We show here that the fungus Fusarium oxysporum rapidly biotransforms the naturally occurring amorphous plant biosilica into crystalline silica and leach out silica extracellularly at room temperature in the form of 2-6 nm quasi-spherical, highly crystalline silica nanoparticles capped by stabilizing proteins; that the nanoparticles are released into solution is an advantage of this process with significant application and commercial potential. Calcination of the silica nanoparticles leads to loss of occluded protein and to an apparently porous structure often of cubic morphology. The room-temperature synthesis of oxide nanomaterials using microorganisms starting from potential cheap agro-industrial waste materials is an exciting possibility and could lead to an energy-conserving and economically viable green approach toward the large-scale synthesis of oxide nanomaterials.

  20. A structural investigation relating to the pozzolanic activity of rice husk ashes

    SciTech Connect

    Nair, Deepa G Fraaij, Alex; Klaassen, Adri A.K.; Kentgens, Arno P.M.

    2008-06-15

    Various factors determine the applicability of rice husk ash (RHA) as a pozzolanic material. The amount and accessibility of reactive sites is thought to be a key factor. A structural study of RHA samples in relation to their reactivity has been performed; Silica in RHA formed by burning rice husk in a laboratory furnace under continuous supply of air have been characterized as a function of incineration temperature, time and cooling regime. The characterization methods included chemical analyses, conductivity measurements, microscopic analysis, X-ray diffraction (XRD) and {sup 29}Si magic-angle spinning (MAS) nuclear magnetic resonance (NMR). In line with earlier observations, the analyses show that the highest amounts of amorphous silica occur in samples burnt in the range of 500 deg. C-700 deg. C. The {sup 29}Si NMR data allow direct identification of the reactive silanol sites in the RHA samples. De-convolution of the NMR spectra clearly shows that the quickly cooled RHA resulting from burning rice husk for 12 h at 500 deg. C has the highest amount of silanol groups. This sample also induced the largest drop in conductivity when added to a saturated calcium hydroxide solution giving an indication of its reactivity towards lime. Therefore, this RHA is the favorable sample to be used as pozzolanic cement additive.

  1. Kinetics, thermodynamics and mechanistic studies of carbofuran removal using biochars from tea waste and rice husks.

    PubMed

    Vithanage, Meththika; Mayakaduwa, S S; Herath, Indika; Ok, Yong Sik; Mohan, Dinesh

    2016-05-01

    This study reports the thermodynamic application and non-linear kinetic models in order to postulate the mechanisms and compare the carbofuran adsorption behavior onto rice husk and tea waste derived biochars. Locally available rice husk and infused tea waste biochars were produced at 700 °C. Biochars were characterized by using proximate, ultimate and surface characterization methods. Batch experiments were conducted at 25, 35, and 45 °C for a series of carbofuran solutions ranging from 5 to 100 mg L(-1) with a biochar dose of 1 g L(-1) at pH 5.0 with acetate buffer. Molar O/C ratios indicated that rice husk biochar (RHBC700) is more hydrophilic than tea waste biochar (TWBC700). Negative ΔG (Gibbs free energy change) values indicated the feasibility of carbofuran adsorption on biochar. Increasing ΔG values with the rise in temperature indicated high favorability at higher temperatures for both RHBC and TWBC. Enthalpy values suggested the involvement of physisorption type interactions. Kinetic data modeling exhibited contribution of both physisorption, via pore diffusion, π*-π electron donor-acceptor interaction, H-bonding, and van der Waals dispersion forces and chemisorption via chemical bonding with phenolic, and amine groups. Equilibrium adsorption capacities of RHBC and TWBC determined by pseudo second order kinetic model were 25.2 and 10.2 mg g(-1), respectively.

  2. Study on concrete with partial replacement of cement by rice husk ash

    NASA Astrophysics Data System (ADS)

    Kaarthik Krishna, N.; Sandeep, S.; Mini, K. M.

    2016-09-01

    Increase in the demand of conventional construction materials and the need for providing a sustainable growth in the construction field has prompted the designers and developers to opt for ‘alternative materials’ feasible for use in construction. For this objective, the use of industrial waste products and agricultural byproducts are very constructive. These industrial wastes and agricultural by products such as Fly Ash, Rice Husk Ash, Silica Fume, and Slag can be replaced instead of cement because of their pozzolanic behavior, which otherwise requires large tract of lands for dumping. In the present investigation, Rice Husk Ash has been used as an admixture to cement in concrete and its properties has been studied. An attempt was also done to examine the strength and workability parameters of concrete. For normal concrete, mix design is done based on Indian Standard (IS) method and taking this as reference, mix design has been made for replacement of Rice Husk Ash. Four different replacement levels namely 5%, 10%, 15% and 20% are selected and studied with respect to the replacement method.

  3. Fabrication of Silica Glass from Rice Husk Ash with Spodumene Additions

    NASA Astrophysics Data System (ADS)

    Wasanapiarnpong, T.; Vorajesdarom, B.; Rujirakamort, E.; Nilpairach, S.; Mongkolkachit, C.

    2011-10-01

    Silica glass is an interesting material due to its low thermal expansion coefficient, high chemical inertness, and transparency. In this study, low cost rice husk ash waste containing mainly amorphous silica phase was used as a starting raw material. Formation of cristrobalite caused product damage during cooling down was suppressed by an addition of some sintering aids. Spodumene was selected to use as the sintering aid due to its ability to promote the sinterability of the rice husk ash by liquid phase forming. Lithium carbonate and aluminum nitrate were mixed with the rice husk ash as starting chemicals for spodumene forming. To investigate the effects of spodumene addition on densification, physical properties and thermal expansion coefficient, 25 and 50 mass% of spdumene were added to the mixture. Mixed powders were dry pressed into pellet shapes and sintered at 1000-1250 °C for 30 min in an electric furnace. It was found that 50 mass% addition of spodumene enhanced the densification of the specimens sintered at the temperature higher than 1250 °C. Water absorption was reduced to 1.11 % with bulk density of 2.12 g/cm3. Low thermal expansion coefficient of 2.70×10-6 /°C was achieved with only the petalite phase detection.

  4. Biosorption of methylene blue from aqueous solution by rice husk in a fixed-bed column.

    PubMed

    Han, Runping; Wang, Yuanfeng; Yu, Weihong; Zou, Weihua; Shi, Jie; Liu, Hongmin

    2007-03-22

    In this study, the ability of rice husk to adsorb methylene blue (MB) from aqueous solution was investigated in a fixed-bed column. The effects of important parameters, such as the value of initial pH, existed salt, the flow rate, the influent concentration of MB and bed depth, were studied. The Thomas model was applied to adsorption of MB at different flow rate, influent concentration and bed depth to predict the breakthrough curves and to determine the characteristic parameters of the column useful for process design using non-linear regression. The bed-depth/service time analysis (BDST) model was also applied at different bed depth to predict the breakthrough curves. The two models were found suitable for describing the biosorption process of the dynamic behavior of the rice husk column. All the results suggested that rice husk as adsorbent to removal MB from solution be efficient, and the rate of biosorption process be rapid. When the flow rate was 8.2ml min(-1) and the influent concentration of MB was 50mgl(-1), the equilibrium adsorption biomass reached 4.41mgg(-1) according to Thomas model.

  5. Performance of rice husk ash produced using a new technology as a mineral admixture in concrete

    SciTech Connect

    Nehdi, M.; Duquette, J.; El Damatty, A

    2003-08-01

    This article investigates the use of a new technique for the controlled combustion of Egyptian rice husk to mitigate the environmental concerns associated with its uncontrolled burning and provide a supplementary cementing material for the local construction industry. The reactor used provides efficient combustion of rice husk in a short residency time via the suspension of processed particles by jets of a process air stream that is forced though stationary angled blades at high velocity. Investigations on the rice husk ash (RHA) thus produced included oxide analysis, X-ray diffraction, carbon content, grindability, water demand, pozzolanic activity index, surface area, and particle size distribution measurements. In addition, concrete mixtures incorporating various proportions of silica fume (SF) and Egyptian RHA (EG-RHA) produced at different combustion temperatures were made and compared. The workability, superplasticizer and air-entraining admixture requirements, and compressive strength at various ages of these concrete mixtures were evaluated, and their resistance to rapid chloride penetrability and deicing salt surface scaling were examined. Test results indicate that contrary to RHA produced using existing technology, the superplasticizer and air-entraining agent requirements did not increase drastically when the RHA developed in this study was used. Compressive strengths achieved by concrete mixtures incorporating the new RHA exceeded those of concretes containing similar proportions of SF. The resistance to surface scaling of RHA concrete was better than that of concrete containing similar proportions of SF. While the chloride penetrability was substantially decreased by RHA, it remained slightly higher than that achieved by SF concrete.

  6. Use of rice husk for the adsorption of congo red from aqueous solution in column mode.

    PubMed

    Han, Runping; Ding, Dandan; Xu, Yanfang; Zou, Weihua; Wang, Yuanfeng; Li, Yufei; Zou, Lina

    2008-05-01

    A continuous fixed bed study was carried out by using rice husk as a biosorbent for the removal of congo red (CR) from aqueous solution. The effects of important factors, such as the value of initial pH, existing salt, the flow rate, the influent concentration of CR and bed depth, were studied. Data confirmed that the breakthrough curves were dependent on flow rate, initial dye concentration and bed depth. Thomas, Adams-Bohart, and Yoon-Nelson models were applied to experimental data to predict the breakthrough curves using non-linear regression and to determine the characteristic parameters of the column useful for process design, while bed depth/service time analysis (BDST) model was used to express the effect of bed depth on breakthrough curves. The results showed that Thomas model was found suitable for the normal description of breakthrough curve at the experimental condition, while Adams-Bohart model was only for a initial part of dynamic behavior of the rice husk column. The data were in good agreement with BDST model. It was concluded that the rice husk column can remove CR from solution.

  7. Insights into aqueous carbofuran removal by modified and non-modified rice husk biochars.

    PubMed

    Mayakaduwa, S S; Herath, Indika; Ok, Yong Sik; Mohan, Dinesh; Vithanage, Meththika

    2016-08-23

    Biochar has been considered as a potential sorbent for removal of frequently detected pesticides in water. In the present study, modified and non-modified rice husk biochars were used for aqueous carbofuran removal. Rice husk biochars were produced at 300, 500, and 700 °C in slow pyrolysis and further exposed to steam activation. Biochars were physicochemically characterized using proximate, ultimate, FTIR methods and used to examine equilibrium and dynamic adsorption of carbofuran. Increasing pyrolysis temperature led to a decrease of biochar yield and increase of porosity, surface area, and adsorption capacities which were further enhanced by steam activation. Carbofuran adsorption was pH-dependant, and the maximum (161 mg g(-1)) occurred in the vicinity of pH 5, on steam-activated biochar produced at 700 °C. Freundlich model best fitted the sorption equilibrium data. Both chemisorption and physisorption interactions on heterogeneous adsorbent surface may involve in carbofuran adsorption. Langmuir kinetics could be applied to describe carbofuran adsorption in a fixed bed. A higher carbofuran volume was treated in a column bed by a steam-activated biochar versus non-activated biochars. Overall, steam-activated rice husk biochar can be highlighted as a promising low-cost sustainable material for aqueous carbofuran removal.

  8. Fixed bed column study for heavy metal removal using phosphate treated rice husk.

    PubMed

    Mohan, S; Sreelakshmi, G

    2008-05-01

    This paper reports the results of the study on the performance of low-cost adsorbent such as raw rice husk (RRH) and phosphate treated rice husk (PRH) in removing the heavy metals such as lead, copper, zinc and manganese. The adsorbent materials adopted were found to be an efficient media for the removal of heavy metals in continuous mode using fixed bed column. The column studies were conducted with 10 mg/l of individual and combined metal solution with a flow rate of 20 ml/min with different bed depths such as 10, 20 and 30 cm. The breakthrough time was also found to increase from 1.3 to 3.5 h for Pb(II), 4.0 to 9.0 h for Cu(II), 12.5 to 25.4h for Zn(II) and 3.0 to 11.3 h for Mn(II) with increase in bed height from 10 to 30 cm for PRH. Different column design parameters like depth of exchange zone, adsorption rate, adsorption capacity, etc. were calculated. It is found that the adsorption capacity and adsorption rate constant were increased and the minimum column bed depth required was reduced when the rice husk is treated with phosphate, when compared with that of RRH.

  9. Raw and Treated Rice Husks as Sorbents for Mercury Removal from Aqueous Solutions

    NASA Astrophysics Data System (ADS)

    Befani, Maria R.; Manariotis, Ioannis D.; Karapanagioti, Hrissi K.; Quintero, César E.

    2014-05-01

    Environmental pollution with heavy metals is a growing problem and the need for adequate and inexpensive techniques for removal is urgent. Sorption is an effective method for removing heavy metals from aqueous solutions. During rice milling, large quantities of rice husk waste are generated. This product is used in part as fuel in drying grain plants, which generates a second byproduct: rice husk ash. By this way, two types of relatively low-cost materials are obtained, which seem to be promising sorbents for the removal of heavy metals from aqueous systems. The aim of this study was to evaluate the ability of two groups of materials obtained from rice residues to remove mercury from aqueous solutions. The first group consisted of different size fractions of rice husk (RH): RH1 (>1.18 mm), RH2 (0.15 to 1.18 mm) and RH3 (<0.15 mm). The second group consisted of rice husk pyrolyzed at different temperatures and sizes to obtain the following biochars: RHA3 (>1.18 mm; 850ºC), RHA4 (0.15 to 1.18 mm; 850ºC), RHA300 (raw; 300ºC). The ash from rice husk pyrolyzed at 800ºC in oven of the grain drying plant (RHA800) was also evaluated. The surface area and pore volume were determined using nitrogen adsorption/desorption at liquid nitrogen temperature. The surface morphology of the materials was characterized by Scanning Electron Microscopy. The BET surface area varied between a minimum of 0.76 m2/g (RH2) and a maximum of 330 m2/g (RHA4). The range of the average pore diameter was between 46 Å (RHA4) to 266 Å (RH2). The pore size distribution analysis showed that the materials were mainly low porous or mesoporous except RHA4 that was microporous (53% of the pore volume for RHA4 is due to micropores). The effect of the initial solution pH on the mercury uptake was studied in the range of 2 to 6, using a contact time of 24 h and an initial concentration (Co) of 50 mg Hg(II)/L. The greatest mercury uptake occurred for pH values between 4 and 5. Four materials were selected

  10. Effect of fluidising velocity on the combustion of rice husk in a bench-scale fluidised bed combustor for the production of amorphous rice husk ash.

    PubMed

    Rozainee, M; Ngo, S P; Salema, A A; Tan, K G; Ariffin, M; Zainura, Z N

    2008-03-01

    This study was focused on investigating the optimum fluidising velocity during the combustion of rice husk in a bench-scale fluidised bed combustor (ID 210mm) to obtain low carbon ash in the amorphous form. When all other parameters are held constant, the optimum fluidizing velocity aids in almost complete combustion, thereby releasing the entrapped carbon for further conversion. This results in ash with consistently low carbon content (less than 2wt%). The range of fluidising velocities investigated was from as low as 1.5U(mf) to as high as 8U(mf). It was found that the optimum fluidising velocity was approximately 3.3U(mf) as the mixing of rice husk with the bed was good with a high degree of penetration into the sand bed. The resulting ash retained its amorphous form with low residual carbon content (at 2.88wt%) and minimal sand contamination as shown by the X-ray diffraction analysis.

  11. Esterification free fatty acid in sludge palm oil using ZrO2/SO42- - rice husk ash catalyst

    NASA Astrophysics Data System (ADS)

    Hidayat, Arif; Sutrisno, Bachrun

    2017-05-01

    Indonesia, as one of the biggest palm oil producers and exporters in the world, is producing large amounts of low-grade oil such as sludge palm oil (SPO) from palm oil industries. The use of SPO can lower the cost of biodiesel production significantly, which makes SPO a highly potential alternative feedstock for biodiesel production. In this paper, the esterification of free fatty acid on sludge palm oil was studied using rice husk ash as heterogeneous solid catalysts. Heterogeneous solid catalysts offer significant advantages of eliminating separation, corrosion, toxicity and environmental problems. In this paper the esterification of SPO, a by-product from palm oil industry, in the presence of modified rice husk ash catalysts was studied. The rice husk ash catalysts were synthesized by impregnating of Zirconia (Zr) on rice husk ash followed by sulfonation. The rice husk ash catalysts were characterized by using different techniques, such as FT-IR, XRD, and porous analysis. The effects of the mass ratio of catalyst to oil (1 - 10%), the molar ratio of methanol to oil (4:1 - 10:1), and the reaction temperature (40 - 60°C) were studied for the conversion of free fatty acids (FFAs) to optimize the reaction conditions. The results showed that the optimal conditions were an methanol to oil molar ratio of 10:1, the amount of catalyst of 10%w, and reaction temperature of 60°C.

  12. A study on the consecutive preparation of d-xylose and pure superfine silica from rice husk.

    PubMed

    Zhang, Hongxi; Zhao, Xu; Ding, Xuefeng; Lei, Hong; Chen, Xue; An, Dongmin; Li, Yunling; Wang, Zichen

    2010-02-01

    Rice husk is an abundant agricultural byproduct. In the present paper, research on consecutive preparation of d-xylose and superfine silica from rice husk is carried out. The optimum hydrolysis conditions of xylan in rice husk to d-xylose are as follows: the concentration of H(2)SO(4) is 4% (wt.%), the temperature is 130 degrees C, the ratio of rice husk mass (g) to H(2)SO(4) solution volume (ml) is 1:4 and the time is 2 h. The hydrolysis degree of xylan reaches 96.22% (wt.%). High purity (98.5%, wt.%) d-xylose is obtained from acid hydrolysis solution with the purification yield of 71.63% (wt.%). At the same time, the metal oxides in rice husk are efficiently dissolved by H(2)SO(4). Residuals from H(2)SO(4) pre-treatment are incinerated under 750 degrees C in stationary air for 15 min. Silica is obtained with the purity of 99.87% (wt.%). The superfine silica powder is obtained after ground and ultrasonic dispersion, with the diameter of 30-200 nm and specific surface 287.86 m(2)/g.

  13. Novel uses of rice-husk-ash (a natural silica-carbon matrix) in low-cost water purification applications

    NASA Astrophysics Data System (ADS)

    Malhotra, Chetan; Patil, Rajshree; Kausley, Shankar; Ahmad, Dilshad

    2013-06-01

    Rice-husk-ash is used as the base material for developing novel compositions to deal with the challenge of purifying drinking water in low-income households in India. For example, rice-husk-ash cast in a matrix of cement and pebbles can be formed into a filtration bed which can trap up to 95% of turbidity and bacteria present in water. This innovation was proliferated in villages across India as a do-it-yourself rural water filter. Another innovation involves embedding silver nanoparticles within the rice husk ash matrix to create a bactericidal filtration bed which has now been commercialized in India as a low-cost for-profit household water purifier. Other innovations include the impregnation of rice-husk-ash with iron hydroxide for the removal of arsenic from water and the impregnation of rice-husk ash with aluminum hydroxide for the removal of fluoride ions from water which together have the potential to benefit over 100 million people across India who are suffering from the health effects of drinking groundwater contaminated with arsenic and fluoride.

  14. Processing of Fireproof and High Temperature Durable Particleboard from Rice Husk

    NASA Astrophysics Data System (ADS)

    Gürü, Metin; Karabulut, Ahmet F.; Aydın, Mustafa Yasir; Bilici, İbrahim

    2015-10-01

    The aim of this study is the recovery of rice husk waste by researching usability in industry as an alternative to wood. In this study urea formaldehyde resin was used mainly as binding agent for wood-panel used in industry. For the preparation of composite material, ground powder rice husks were mixed with urea formaldehyde resin used in different proportions (65/50, 75/50, 80/50, 85/50, 95/50 by mass of filler/binder). Each particleboard produced in 393.15 K and 9.8 MPa pressure was tested by means of three point bending strength, shore hardness and limited oxygen index (LOI) tests. Particleboard made with 75/50 paddy husk/urea formaldehyde composition material formed of 11.40 MPa specimens showed the highest strength. Limited oxygen index value increased by increasing the filler material usage. The highest LOI value was recorded as 40%. Besides, fire point of particleboards which have the best three point bending strength has been analyzed at environmental atmosphere and 493.15 K has been measured as fire point. The results of the tests showed that this material maybe used instead of wooden plate. The usage of agricultural wastes like these in processing of particleboard will give economically benefits and slow down waste products.

  15. Synthesis of ZSM-5 zeolite using silica from rice husk ash

    SciTech Connect

    Rawtani, A.V.; Rao, M.S. ); Gokhale, K.V.G.K. )

    1989-09-01

    The authors describe ZSM-5 zeolite synthesized from the Na-TPA cation system for the first time using silica from rice husk ash. In this study, rice husk ash was the only source of silica and alumina used in the synthesis. The molar ratio of SiO/sub 2//Al/sub 2/O/sub 3/ in the husk was 24.88, which was constant throughout. The synthesis has been carried out for temperatures ranging from 125 to 200{sup 0}C and durations of synthesis has from 6 to 120 h with Na/sub 2/O/Al/sub 2/O/sub 3/ and H/sub 2/O/Al/sub 2/O/sub 3/ molar ratios ranging from 3.25 to 15.15 and 1081 to 2786, respectively. The effects of varying the composition of initial mixture, the alkalinity, and the time on synthesis were studied. The product at each stage has been characterized by using X-ray diffraction analysis, infrared spectroscopy, differential scanning calorimetry, and electron microscopy.

  16. Pyrolysis of agricultural biomass residues: Comparative study of corn cob, wheat straw, rice straw and rice husk.

    PubMed

    Biswas, Bijoy; Pandey, Nidhi; Bisht, Yashasvi; Singh, Rawel; Kumar, Jitendra; Bhaskar, Thallada

    2017-02-23

    Pyrolysis studies on conventional biomass were carried out in fixed bed reactor at different temperatures 300, 350, 400 and 450°C. Agricultural residues such as corn cob, wheat straw, rice straw and rice husk showed that the optimum temperatures for these residues are 450, 400, 400 and 450°C respectively. The maximum bio-oil yield in case of corn cob, wheat straw, rice straw and rice husk are 47.3, 36.7, 28.4 and 38.1wt% respectively. The effects of pyrolysis temperature and biomass type on the yield and composition of pyrolysis products were investigated. All bio-oils contents were mainly composed of oxygenated hydrocarbons. The higher area percentages of phenolic compounds were observed in the corn cob bio-oil than other bio-oils. From FT-IR and (1)H NMR spectra showed a high percentage of aliphatic functional groups for all bio-oils and distribution of products is different due to differences in the composition of agricultural biomass.

  17. Influence of ultrasonic pretreatment on the yield of bio-oil prepared by thermo-chemical conversion of rice husk in hot-compressed water.

    PubMed

    Shi, Wen; Jia, Jingfu; Gao, Yahui; Zhao, Yaping

    2013-10-01

    The aim of the current study is to investigate the feasibility of thermo-chemical conversion of rice husk in hot-compressed water via ultrasonic pretreatment to increase the bio-oil yield. The results show that ultrasonic pretreatment remarkably changes the structures of the rice husk, such as enhancing swelling and surface area, eroding lignin structure, and resulting in more exposure of the cellulose and hemicellulose. The highest bio-oil yield of 42.8% was obtained from the thermo-chemical conversion at 300 °C and 0 min of the residence time for the 1 h pretreated rice husk. GC-MS analysis indicates that the relative contents of phenols, 5-Hydroxymethylfurfural, and lactic acid are higher in bio-oils obtained from the pretreated rice husks than that from the raw rice husk.

  18. Fabrication and characterization of rice husk and coconut shell charcoal based bio-briquettes as alternative energy source

    NASA Astrophysics Data System (ADS)

    Yuliah, Y.; Kartawidjaja, M.; Suryaningsih, S.; Ulfi, K.

    2017-05-01

    Rice husk and coconut shell have been disposed or burned as waste. As biomass, both of materials are the potential sources of carbon which can be utilized as alternative energy sources. The energy content can be exploited more intensively when packaged in a brief and convenient. In this work, the mixtures of rice husks and coconut shells charcoal were prepared as briquettes. After going through the carbonization process, several measurements have been taken to find out the factors that determine the value of heat energy contains by each component of the charcoals. The basic ingredients briquettes prepared from rice husk and coconut shell charcoal with varying composition and addition of tapioca starch gradually as adhesive material to obtain briquettes in solid with the maximum heat energy content. After going through pressing and drying process, the briquettes with 50:50 percent of composition and the 6% addition of adhesive was found has the highest heat energy content, equal to 4966 cal/g.

  19. Facile, room-temperature pre-treatment of rice husks with tetrabutylphosphonium hydroxide: Enhanced enzymatic and acid hydrolysis yields.

    PubMed

    Lau, B B Y; Luis, E T; Hossain, M M; Hart, W E S; Cencia-Lay, B; Black, J J; To, T Q; Aldous, L

    2015-12-01

    Aqueous solutions of tetrabutylphosphonium hydroxide have been evaluated as pretreatment media for rice husks, prior to sulphuric acid hydrolysis or cellulase enzymatic hydrolysis. Varying the water:tetrabutylphosphonium hydroxide ratio varied the rate of delignification, as well as silica, lignin and cellulose solubility. Pre-treatment with 60wt% hydroxide dissolved the rice husk and the regenerated material was thus heavily disrupted. Sulphuric acid hydrolysis of 60wt%-treated samples yielded the highest amount of glucose per gram of rice husk. Solutions with good lignin and silica solubility but only moderate to negligible cellulose solubility (10-40wt% hydroxide) were equally effective as pre-treatment media for both acid and enzymatic hydrolysis. However, pre-treatment with 60wt% hydroxide solutions was incompatible with downstream enzymatic hydrolysis. This was due to significant incorporation of phosphonium species in the regenerated biomass, which significantly inhibited the activity of the cellulase enzymes.

  20. Pb(II), Cu(II) and Cd(II) removal through untreated rice husk; thermodynamics and kinetics.

    PubMed

    Guiso, Maria Giovanna; Alberti, Giancarla; Emma, Giovanni; Pesavento, Maria; Biesuz, Raffaela

    2012-01-01

    The sorption properties of rice husk towards Cu(II), Cd(II) and Pb(II) were studied. The sorption isotherms are described by the Langmuir equation, and Pb(II) shows a higher affinity for rice husk compared to Cu(II) and Cd(II) under the same conditions. The kinetics of sorption obeys to a pseudo second-order equation for all metals. The sorption profiles as a function of the pH were used to characterize the stoichiometry of the sorption reaction. The competition for metal complexation by any ligand in solution is also accounted for. Upon increasing the ionic strength, the sorption curves of Pb(II) move to basic pH; this shift can be explained by considering the effect of nitrate complexes on the free metal ion concentration, since KNO(3) is used as the ionic medium. An attempt to employ rice husk in a dynamic system is presented.

  1. Upgrading the rice husk char obtained by flash pyrolysis for the production of amorphous silica and high quality activated carbon.

    PubMed

    Alvarez, Jon; Lopez, Gartzen; Amutio, Maider; Bilbao, Javier; Olazar, Martin

    2014-10-01

    The overall valorization of rice husk char obtained by flash pyrolysis in a conical spouted bed reactor (CSBR) has been studied in a two-step process. Thus, silica has been recovered in a first step and the remaining carbon material has been subjected to steam activation. The char samples used in this study have been obtained by continuous flash pyrolysis in a conical spouted bed reactor at 500°C. Extraction with Na2CO3 allows recovering 88% of the silica contained in the rice husk char. Activation of the silica-free rice husk char has been carried out in a fixed bed reactor at 800°C using steam as activating agent. The porous structure of the activated carbons produced includes a combination of micropores and mesopores, with a BET surface area of up to 1365m(2)g(-1) at the end of 15min. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. A preliminary study for removal of heavy metals from acidic synthetic wastewater by using pressmud-rice husk mixtures

    NASA Astrophysics Data System (ADS)

    Ahmad, H.; Ee, C. J.; Baharudin, N. S.

    2016-06-01

    The study was carried out to evaluate the effect of combining pressmud and rice husk in the removal efficiencies of heavy metals in acidic synthetic wastewater. The ratios of pressmud to rice husk were varied at different percentages of weight ratio (0%, 20%, 40%, 60% 80% and 100%) and removal of heavy metals concentrations was observed. The result showed that the removal efficiency was increased with the addition of pressmud by up to almost 100%. Pressmud alone was able to remove 95% to 100% of heavy metals while rice husk alone managed to remove only 10% to 20% of heavy metals. The study also demonstrated that pressmud behaved as a natural acid neutralizer. Hence, the initial pH of the synthetically prepared acidic wastewater which was below 2 also was increased to pH ranging from 6 to 8.

  3. Comparison on the Surface Structure Properties along with Fe(II) and Mn(II) Removal Characteristics of Rice Husk Ash, Inactive Saccharomyces cerevisiae Powder, and Rice Husk

    PubMed Central

    Jiang, Zhao; Cao, Bo; Su, Guangxia; Lu, Yan; Zhao, Jiaying; Shan, Dexin; Zhang, Xiuyuan; Wang, Ziyi

    2016-01-01

    This study selected solid wastes, such as rice husk ash (RHA), inactive Saccharomyces cerevisiae powder (ISP), and rice husk (RH), as the potential adsorbents for the removal of Fe(II) and Mn(II) in aqueous solution. The structural characteristics, functional groups, and elemental compositions were determined by scanning electron microscope (SEM) and Fourier translation infrared spectrum (FT-IR) analyses, respectively. Then the influence on the Fe(II) and Mn(II) removing efficiency by the factors, such as pH, adsorbent dosage, initial Fe(II) and Mn(II) concentration, and contact time, was investigated by the static batch test. The adsorption isotherm study results show that Langmuir equation can better fit the Fe(II) and Mn(II) adsorption process by the three adsorbents. The maximum adsorption amounts for Fe(II) were 6.211 mg/g, 4.464 mg/g, and 4.049 mg/g by RHA, ISP, and RH and for Mn(II) were 3.016 mg/g, 2.229 mg/g, and 1.889 mg/g, respectively. The adsorption kinetics results show that the pseudo-second-order kinetic model can better fit the Fe(II) and Mn(II) adsorption process. D-R model and thermodynamic parameters hint that the adsorption processes of Fe(II) and Mn(II) on the three adsorbents took place physically and the processes were feasible, spontaneous, and exothermic. PMID:28042571

  4. Comparison on the Surface Structure Properties along with Fe(II) and Mn(II) Removal Characteristics of Rice Husk Ash, Inactive Saccharomyces cerevisiae Powder, and Rice Husk.

    PubMed

    Jiang, Zhao; Cao, Bo; Su, Guangxia; Lu, Yan; Zhao, Jiaying; Shan, Dexin; Zhang, Xiuyuan; Wang, Ziyi; Zhang, Ying

    2016-01-01

    This study selected solid wastes, such as rice husk ash (RHA), inactive Saccharomyces cerevisiae powder (ISP), and rice husk (RH), as the potential adsorbents for the removal of Fe(II) and Mn(II) in aqueous solution. The structural characteristics, functional groups, and elemental compositions were determined by scanning electron microscope (SEM) and Fourier translation infrared spectrum (FT-IR) analyses, respectively. Then the influence on the Fe(II) and Mn(II) removing efficiency by the factors, such as pH, adsorbent dosage, initial Fe(II) and Mn(II) concentration, and contact time, was investigated by the static batch test. The adsorption isotherm study results show that Langmuir equation can better fit the Fe(II) and Mn(II) adsorption process by the three adsorbents. The maximum adsorption amounts for Fe(II) were 6.211 mg/g, 4.464 mg/g, and 4.049 mg/g by RHA, ISP, and RH and for Mn(II) were 3.016 mg/g, 2.229 mg/g, and 1.889 mg/g, respectively. The adsorption kinetics results show that the pseudo-second-order kinetic model can better fit the Fe(II) and Mn(II) adsorption process. D-R model and thermodynamic parameters hint that the adsorption processes of Fe(II) and Mn(II) on the three adsorbents took place physically and the processes were feasible, spontaneous, and exothermic.

  5. Comparison between rice husk ash grown in different regions for stabilizing fly ash from a solid waste incinerator.

    PubMed

    Benassi, L; Bosio, A; Dalipi, R; Borgese, L; Rodella, N; Pasquali, M; Depero, L E; Bergese, P; Bontempi, E

    2015-08-15

    The Stabilization of heavy metals from municipal solid waste incineration (MSWI) fly ash by rice husk ash (RHA) is under intense study as an effective strategy to recover and reuse industrial and agricultural waste together. We compare the metal entrapment performances of RHA from different Asian rice sources – namely from Japonica rice grown in Italy and Indica rice grown in India – Physicochemical and morphological characterization of the final stabilized material show that the same thermal treatment may result in marked structural differences in the silica contained in the two RHA. Remarkably, one of them displays a crystalline silica content, although obtained by a thermal treatment below 800 °C. We also find that the presence of an alkali metal ion (potassium) in the rice husk plays a crucial role in the attainment of the final silica phase. These physicochemical differences are mirrored by different stabilization yields by the two RHA.

  6. Removal of copper (II) ion from aqueous solution using zeolite Y synthesized from rice husk ash: Equilibrium and kinetic study

    NASA Astrophysics Data System (ADS)

    Tuyen, Nguyen Thi Kim; Nhan, Do Nguyen Thanh; Nhat, Trieu Thi; An, Ngo Thanh; Long, Nguyen Quang

    2017-09-01

    Zeolite Y was synthesized from silica of rice-husk ash using hydrothermal process. The crystalline structure FAU of zeolite Y was characterized by X-ray diffraction (XRD). Surface's area of the catalyst was determined by physic-adsorption method using BET model. The zeolite was examined for possibility of Cu2+ adsorbent by an ion-exchange mechanism. Various adsorption isotherm models, such as Langmuir, Freundlich and Dubinin-Radushkevich were tested for equilibrium study. The integration method was applied to find out the possible kinetic equation of the Cu2+ adsorption on the zeolite Y which obtained from cheap and locally available rice husk ash.

  7. Design of multiple-layer microwave absorbing structure based on rice husk and carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Seng, Lee Yeng; Wee, F. H.; Rahim, H. A.; AbdulMalek, MohamedFareq; You, Y. K.; Liyana, Z.; Ezanuddin, A. A. M.

    2017-01-01

    This paper presents a multiple-layered microwave absorber using rice husk and carbon nanotube composite. The dielectric properties of each layer composite were measured and analysed. The different layer of microwave absorber enables to control the microwave absorption performance. The microwave absorption performances are demonstrated through measurements of reflectivity over the frequency range 2-18 GHz. An improvement of microwave absorption <-20 dB is observed with respect to a high lossy composite placed at bottom layer of multiple layers. Reflectivity evaluations indicate that the composites display a great potential application as wideband electromagnetic wave absorbers.

  8. Ultrasonic and conventional synthesis of NaA zeolite from rice husk ash

    NASA Astrophysics Data System (ADS)

    Farías, T.; de Ménorval, LC; Picazo, O.; Jordán, R.

    2017-01-01

    In the present work, a simple synthetic route for the production of single phase NaA zeolite is demonstrated. Rice husk ash (RHA) as alternative silica source was employed for the synthesis by conventional hydrothermal and non-conventional ultrasound methods. The zeolite was also synthesized using commercially available silicate for comparison. The effect of the reaction time (2, 4 and 6 h) at a fixed temperature of 70 °C was investigated. The elemental, structural and morphological characterization of the ashes and the synthesized zeolites was performed by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and thermogravimetric analysis (TG/DSC).

  9. Effect of rice husk gasification residue application on herbicide behavior in micro paddy lysimeter.

    PubMed

    Ok, Junghun; Pisith, Sok; Watanabe, Hirozumi; Thuyet, Dang Quoc; Boulange, Julien; Takagi, Kazuhiro

    2015-06-01

    Effects of rice husk gasification residues (RHGR) application on the fate of herbicides, butachlor and pyrazosulfuron-ethyl, in paddy water were investigated using micro paddy lysimeters (MPLs). The dissipation of both herbicides in paddy water was faster in the RHGR treated MPL than in the control MPL. The average concentrations of butachlor and pyrazosulfuron-ethyl in paddy water in the lysimeter treated with RHGR during 21 days were significantly reduced by 51% and 48%, respectively, as compared to those in the lysimeter without RHGR application. The half-lives (DT50) of butachlor in paddy water for control and treatment were 3.1 and 2.3 days respectively, and these values of pyrazosulfuron-ethyl were 3.0 and 2.2 days, respectively. Based on this study, RHGR application in rice paddy environment is an alternative method to reduce the concentration of herbicide in paddy field water and consequently to reduce potential pollution to aquatic environment.

  10. Pozzolanic Characterization Of Waste Rice Husk Ash (RHA) From Muar, Malaysia

    NASA Astrophysics Data System (ADS)

    Hadipramana, J.; Riza, F. V.; Rahman, I. A.; Loon, L. Y.; Adnan, S. H.; Zaidi, A. M. A.

    2016-11-01

    Investigation of Rice Husk Ash (RHA) thoroughly under controlled burning is regular issue to obtain result to produce the amorphous silica that has high pozzolanic reactivity characteristic. This paper offered an observation about characteristic of ground and un-ground of un-controlled burning temperature RHA that were taken from rice millings in Muar, Johor Malaysia. Such tests as X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD), Particle Size Analysis and Specific Area Surface, Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron microscope (SEM) were conducted in this investigation to carry out the characteristic of RHA samples. The results show that the RHA was consist approximately 89.90% of silica and the RHA possessed the amorphous particle were dominant than its crystalline part. This proves that the RHA has a big potential as a pozzolanic material considering the silica content and porous structure. In addition, particle size analysis decides whether the pozzolanic reactivity can be increased by grinding process.

  11. Comparing dry ashing and wet oxidation methods. The case of the rice husk (Oryza sativa L.).

    PubMed

    Sun, Xiuping; Wu, Yan; Wang, Changsui; Hill, David V

    2012-09-01

    Experiments were conducted to determine the effects that different methods for the preparation of modern plant samples have on the resulting phytoliths using rice husks (Oryza sp.). The methods that are commonly used in phytolith extraction include (1) dry ashing, (2) acid extraction (3) a combination of both techniques. The results showed that processing methods have an impact on the morphology of two subspecies of rice phytoliths, dry ashing producing more conjoined cell phytoliths or multicells phytoliths than acid extraction. Using a combination of both methods resulted in the presence of fewer conjoined cells than dry ashing alone, but more conjoined cells than acid extraction. Alternative explanations are proposed to explain the formation of conjoined phytolith cells. Copyright © 2012 Wiley Periodicals, Inc.

  12. Facile fabrication of rice husk based silicon dioxide nanospheres loaded with silver nanoparticles as a rice antibacterial agent

    PubMed Central

    Cui, Jianghu; Liang, You; Yang, Desong; Liu, Yingliang

    2016-01-01

    Bacterial leaf blight of rice caused by Xanthomonas oryzae pv. oryzae (Xoo) is a major disease of rice, leading to reduction in production by 10–50%. In order to control this disease, various chemical bactericides have been used. Wide and prolonged application of chemical bactericides resulted in the resistant strain of Xoo that was isolated from rice. To address this problem, we were searching for an environmentally friendly alternative to the commonly used chemical bactericides. In this work, we demonstrate that silicon dioxide nanospheres loaded with silver nanoparticles (SiO2-Ag) can be prepared by using rice husk as base material precursor. The results of the antibacterial tests showed that SiO2-Ag composites displayed antibacterial activity against Xoo. At cellular level, the cell wall/membrane was damaged and intercellular contents were leaked out by slow-releasing of silver ions from SiO2-Ag composites. At molecular level, this composite induced reactive oxygen species production and inhibited DNA replication. Based on the results above, we proposed the potential antibacterial mechanism of SiO2-Ag composites. Moreover, the cytotoxicity assay indicated that the composites showed mild toxicity with rice cells. Thus, this work provided a new strategy to develop biocide derived from residual biomass. PMID:26888152

  13. Facile fabrication of rice husk based silicon dioxide nanospheres loaded with silver nanoparticles as a rice antibacterial agent.

    PubMed

    Cui, Jianghu; Liang, You; Yang, Desong; Liu, Yingliang

    2016-02-18

    Bacterial leaf blight of rice caused by Xanthomonas oryzae pv. oryzae (Xoo) is a major disease of rice, leading to reduction in production by 10-50%. In order to control this disease, various chemical bactericides have been used. Wide and prolonged application of chemical bactericides resulted in the resistant strain of Xoo that was isolated from rice. To address this problem, we were searching for an environmentally friendly alternative to the commonly used chemical bactericides. In this work, we demonstrate that silicon dioxide nanospheres loaded with silver nanoparticles (SiO2-Ag) can be prepared by using rice husk as base material precursor. The results of the antibacterial tests showed that SiO2-Ag composites displayed antibacterial activity against Xoo. At cellular level, the cell wall/membrane was damaged and intercellular contents were leaked out by slow-releasing of silver ions from SiO2-Ag composites. At molecular level, this composite induced reactive oxygen species production and inhibited DNA replication. Based on the results above, we proposed the potential antibacterial mechanism of SiO2-Ag composites. Moreover, the cytotoxicity assay indicated that the composites showed mild toxicity with rice cells. Thus, this work provided a new strategy to develop biocide derived from residual biomass.

  14. Air gasification of rice husk in bubbling fluidized bed reactor with bed heating by conventional charcoal.

    PubMed

    Makwana, J P; Joshi, Asim Kumar; Athawale, Gaurav; Singh, Dharminder; Mohanty, Pravakar

    2015-02-01

    An experimental study of air gasification of rice husk was conducted in a bench-scale fluidized bed gasifier (FBG) having 210 mm diameter and 1600 mm height. Heating of sand bed material was performed using conventional charcoal fuel. Different operating conditions like bed temperature, feeding rate and equivalence ratio (ER) varied in the range of 750-850 °C, 25-31.3 kg/h, and 0.3-0.38, respectively. Flow rate of air was kept constant (37 m(3)/h) during FBG experiments. The carbon conversion efficiencies (CCE), cold gas efficiency, and thermal efficiency were evaluated, where maximum CCE was found as 91%. By increasing ER, the carbon conversion efficiency was decreased. Drastic reduction in electric consumption for initial heating of gasifier bed with charcoal compared to ceramic heater was ∼45%. Hence rice husk is found as a potential candidate to use directly (without any processing) in FBG as an alternative renewable energy source from agricultural field.

  15. Sorption of lanthanum and erbium from aqueous solution by activated carbon prepared from rice husk.

    PubMed

    Awwad, N S; Gad, H M H; Ahmad, M I; Aly, H F

    2010-12-01

    A biomass agricultural waste material, rice husk (RH) was used for preparation of activated carbon by chemical activation using phosphoric acid. The effect of various factors, e.g. time, pH, initial concentration and temperature of carbon on the adsorption capacity of lanthanum and erbium was quantitatively determined. It was found that the monolayer capacity is 175.4 mg g(-1) for La(III) and 250 mg g(-1) for Er(III). The calculated activation energy of La(III) adsorption on the activated carbon derived from rice husk was equal to 5.84 kJ/mol while it was 3.6 kJ/mol for Er(III), which confirm that the reaction is mainly particle-diffusion-controlled. The kinetics of sorption was described by a model of a pseudo-second-order. External diffusion and intra-particular diffusion were examined. The experimental data show that the external diffusion and intra-particular diffusion are significant in the determination of the sorption rate. Therefore, the developed sorbent is considered as a better replacement technology for removal of La(III) and Er(III) ions from aqueous solution due to its low-cost and good efficiency, fast kinetics, as well as easy to handle and thus no or small amount of secondary sludge is obtained in this application.

  16. Adsorption of crude and engine oils from water using raw rice husk.

    PubMed

    Razavi, Zahra; Mirghaffari, Nourollah; Rezaei, Behzad

    2014-01-01

    The raw rice husk (RRH) was used as a low cost adsorbent to remove three oil compounds with different viscosities (crude oil, engine oil and spent engine oil) from an aqueous environment. Some of the sorbent specifications were characterized using a CHNSO analyzer, Fourier transform infrared, scanning electron microscope and inductively coupled plasma spectroscopy. With decreasing RRH particles size, the oil adsorption percentage was reduced for crude, spent and engine oils from 50 to 30%, 65 to 20% and 70 to 0.01%, respectively. This was probably due to damage of the microcavities. The removal percentage by sorbent at optimized conditions was 88, 80 and 55% for engine, spent and crude oils, respectively, corresponding to their descending viscosity. The adsorption of crude and spent oils on rice husk followed the Freundlich isotherm model, while the adsorption of engine oil was fitted by the Langmuir model. The maximum adsorption capacity (qmax), calculated from the Langmuir model for the adsorption of engine oil on RRH, was 1,250 mg/g.

  17. Esterification free fatty acid in palm fatty acid distillate using sulfonated rice husk ash catalyst

    NASA Astrophysics Data System (ADS)

    Hidayat, Arif; Sutrisno, Bachrun

    2017-01-01

    Indonesia, as one of the biggest palm oil producers and exporters in the world, is producing large amounts of low-grade oil such as Palm Fatty Acid Distillate (PFAD) from palm oil industries. The use of PFAD can reduce the cost of biodiesel production significantly, which makes PFAD a highly potential alternative feedstock for biodiesel production. In this paper, the esterification of free fatty acid (FFA) on PFAD was studied using rice husk ash (RHA) as heterogeneous catalyst. The rice husk ash catalyst was synthesized by sulfonation using concentrated sulfuric acid. The RHA catalyst were characterized by using different techniques, such as porosity analysis, Fourier transform infrared (FT-IR) spectroscopy, total number of acid sites and elemental analysis. The effects of the molar ratio of methanol to PFAD (1-10%), the molar ratio of methanol to PFAD (4:1-10:1), and the reaction temperature (40-60°C) were studied for the conversion of FFA to optimize the reaction conditions. The results showed that the optimal conditions were an methanol to PFAD molar ratio of 10:1, the catalyst amount of 10 wt% of PFAD, and reaction temperature of 60°C.

  18. Effects of water washing and torrefaction pretreatments on rice husk pyrolysis by microwave heating.

    PubMed

    Zhang, Shuping; Dong, Qing; Zhang, Li; Xiong, Yuanquan; Liu, Xinzhi; Zhu, Shuguang

    2015-10-01

    The influences of water washing, torrefaction and combined water washing-torrefaction pretreatments on microwave pyrolysis of rice husk samples were investigated. The results indicated that the process of combined water washing-torrefaction pretreatment could effectively remove a large portion of inorganics and improve the fuel characteristics to a certain extent. The gas products were rich in combustible compositions and the syngas quality was improved by pretreatment process. The liquid products contained less moisture content, acids and furans, while more concentrated phenols and sugars from microwave pyrolysis of rice husk after pretreatments, especially after the combined water washing-torrefaction pretreatment. Biochar, produced in high yield, has the alkaline pH (pH 8.2-10.0) and high surface area (S(BET) 157.81-267.84 m(2)/g), they have the potential to be used as soil amendments. It is noteworthy that water washing increased the pore surface area of biochar, but torrefaction reduced the pore surface area. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Gasification of agricultural residues in a demonstrative plant: Vine pruning and rice husks.

    PubMed

    Biagini, Enrico; Barontini, Federica; Tognotti, Leonardo

    2015-10-01

    Tests with vine pruning and rice husks were carried out in a demonstrative downdraft gasifier (350 kW), to prove the reactor operability, quantify the plant efficiency, and thus extend the range of potential energy feedstocks. Pressure drops, syngas flow rate and composition were monitored to study the material and energy balances, and performance indexes. Interesting results were obtained for vine pruning (syngas heating value 5.7 MJ/m(3), equivalent ratio 0.26, cold gas efficiency 65%, power efficiency 21%), while poorer values were obtained for rice husks (syngas heating value 2.5-3.8 MJ/m(3), equivalent ratio 0.4, cold gas efficiency 31-42%, power efficiency 10-13%). The work contains also a comparison with previous results (wood pellets, corn cobs, Miscanthus) for defining an operating diagram, based on material density and particle size and shape, and the critical zones (reactor obstruction, bridging, no bed buildup, combustion regime). Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Rice Husk Ash-Derived Silica Nanofluids: Synthesis and Stability Study.

    PubMed

    Zhang, Zhiliang; He, Wenxiu; Zheng, Jianzhong; Wang, Guangquan; Ji, Jianbing

    2016-12-01

    Nanofluids, colloidal suspensions consisting of base fluids and nanoparticles, are a new generation of engineering working fluids. Nanofluids have shown great potential in heat/mass transfer applications. However, their practical applications are limited by the high production cost and low stability. In this study, a low-cost agricultural waste, rice husk ash (RHA), was used as a silicon source to the synthesis of silica nanofluids. First, silica nanoparticles with an average size of 47 nm were synthesized. Next, by dispersing the silica nanoparticles in water with ultrasonic vibration, silica nanofluids were formed. The results indicated that the dispersibility and stability of nanofluids were highly dependent on sonication time and power, dispersant types and concentrations, as well as pH; an optimal experiment condition could result in the highest stability of silica nanofluid. After 7 days storage, the nanofluid showed no sedimentation, unchanged particle size, and zeta potential. The results of this study demonstrated that there is a great potential for the use of RHA as a low-cost renewable resource for the production of stable silica nanofluids. Graphical Abstract Rice husk ash was used as a low-cost renewable resource for production of silica nanofluids with high stability.

  1. Synthesis of belite cement from nano-silica extracted from two rice husk ashes.

    PubMed

    Sinyoung, Suthatip; Kunchariyakun, Kittipong; Asavapisit, Suwimol; MacKenzie, Kenneth J D

    2017-04-01

    Nano-silicas extracted from a pure rice husk ash calcined in the laboratory (RHA) and ash from an impure industrial rice husk waste (BRHA), were used to form belite cement by firing with two different calcium sources (calcium carbonate and calcium nitrate). The nano-silica extracted from RHA was highly reactive due to its high pore volume and low activation energy of dehydration. The formation of belite cement from both nano-silicas was studied by firing with two different calcium sources, Ca(NO3)2 and CaCO3 at 800-1100 °C. Both nano-silicas formed the principal phase in belite cement (larnite or β-C2S) at temperatures as low as 800 °C, especially with calcium nitrate as the calcium source. Thus, highly impure BRHA is shown to be very suitable as a starting material for the low-temperature production of belite cement, especially in conjunction with calcium nitrate as the calcium source.

  2. Upgrading of bio-oil from the pyrolysis of biomass over the rice husk ash catalysts

    NASA Astrophysics Data System (ADS)

    Sutrisno, B.; Hidayat, A.

    2016-11-01

    The pyrolysis oils are complex mixtures of organic compounds that exhibit a wide spectrum of chemical functionality, and generally contain some water. Their direct use as fuels may present some difficulties due to their high viscosity, poor heating value, corrosiveness and instability. For possible future use as replacements for hydrocarbon chemical feedstocks and fuels, the liquids will require considerable upgrading to improve its characteristics. By esterification of the bio oil as the upgrading method, the properties of the bio-oil could be improved. In the paper, the upgrading of a bio-oil obtained by pyrolysis was studied over rice husk ash catalysts. The raw bio-oil was produced by pyrolysis of rice husk.From the experiment results, it can be concluded that the densities of upgraded bio-oil were reduced from 1.24 to 0.95 g.cm-3, and the higherheating value increased from 16.0 to 27.2 MJ/kg and the acidity of upgraded bio-oil was also alleviated from 2.3 to 4.4. The results of gas chromatography-mass spectrometry (GC-MS) and FT-IR analysis showed that the ester compounds in the upgraded bio-oil increased. It is possible to improve the properties of bio-oil by esterifying the raw bio-oil.

  3. Use of Almond Shells and Rice Husk as Fillers of Poly(Methyl Methacrylate) (PMMA) Composites

    PubMed Central

    Sabbatini, Alessandra; Lanari, Silvia; Santulli, Carlo

    2017-01-01

    In recent years, wood fibres have often been applied as the reinforcement of thermoplastic materials, such as polypropylene, whereas their use in combination with thermosetting resin has been less widespread. This study concerns the production of PMMA-based composites by partly replacing alumina trihydrate (ATH) with wood waste fillers, namely rice husks and almond shells, which would otherwise be disposed by incineration. The amount of filler introduced was limited to 10% as regards rice husks and 10 or 15% almond shells, since indications provided by reactivity tests and viscosity measurements did not suggest the feasibility of total replacement of ATH. As a matter of fact, the introduction of these contents of wood waste filler in PMMA-based composite did not result in any significant deterioration of its mechanical properties (Charpy impact, Rockwell M hardness and flexural performance). Some reduction of these properties was only observed in the case of introduction of 15% almond shells. A further issue concerned the yellowing of the organic filler under exposure to UV light. On the other hand, a very limited amount of water was absorbed, never exceeding values around 0.6%, despite the significant porosity revealed by the filler’s microscopic evaluation. These results are particularly interesting in view of the application envisaged for these composites, i.e., wood replacement boards. PMID:28773234

  4. Biocompatibility assessment of rice husk-derived biogenic silica nanoparticles for biomedical applications.

    PubMed

    Alshatwi, Ali A; Athinarayanan, Jegan; Periasamy, Vaiyapuri Subbarayan

    2015-02-01

    Synthetic forms of silica have low biocompatibility, whereas biogenic forms have myriad beneficial effects in current toxicological applications. Among the various sources of biogenic silica, rice husk is considered a valuable agricultural biomass material and a cost-effective resource that can provide biogenic silica for biomedical applications. In the present study, highly pure biogenic silica nanoparticles (bSNPs) were successfully harvested from rice husks using acid digestion under pressurized conditions at 120°C followed by a calcination process. The obtained bSNPs were subjected to phase identification analysis using X-ray diffraction, which revealed the amorphous nature of the bSNPs. The morphologies of the bSNPs were observed using transmission electron microscopy (TEM), which revealed spherical particles 10 to 30 nm in diameter. Furthermore, the biocompatibility of the bSNPs with human lung fibroblast cells (hLFCs) was investigated using a viability assay and assessing cellular morphological changes, intracellular ROS generation, mitochondrial transmembrane potential and oxidative stress-related gene expression. Our results revealed that the bSNPs did not have any significant incompatibility in these in vitro cell-based approaches. These preliminary findings suggest that bSNPs are biocompatible, could be the best alternative to synthetic forms of silica and are applicable to food additive and biomedical applications.

  5. Morphology of the cross section of silica layer in rice husk.

    PubMed

    Byun, Sung Chun; Jung, In Ok; Kim, Moon Yong; So, Soo Jeong; Yoon, Chan; Kim, Chul; Lei, Guo; Han, Chong Soo

    2011-02-01

    The physical adsorption of nitrogen and gas flow experiments on the silica layer in rice husk indicated that an existence of nano meter sized through holes. In this study, the external shape of the holes on the cross section of the layer was investigated with a scanning electron microscope equipped with an energy dispersive spectrometer, an atomic force microscope and scanning tunneling microscope. In the energy dispersive mapping image, 2-5 micron thick silica layer under outer cellulose layer, silica nano particles in the middle cellulose layer and sub micron silica layer in inner cellulose layer were observed. The cross section of the layer showed 20 nm building units with approximately 100 nm convexities. The atomic force microscopic image also showed the approximately 100 nm convexities as well as a roughness of approximately 20 nm. When osmium was coated on the silica layer, the wells with 2 approximately 5 nm horizontal and approximately 2 nm vertical lengths were observed on the plate surface in scanning tunneling microscopic image. From the results, it was suggested that the holes in the rice husk silica layer are almost straight and not zigzag spaces originated from the simple packing of nano particles.

  6. Briquettes of rice husk, polyethylene terephthalate (PET), and dried leaves as implementation of wastes recycling

    NASA Astrophysics Data System (ADS)

    Hariyanto, Sucipto; Usman, Mohammad Nurdianfajar; Citrasari, Nita

    2017-06-01

    This research aim is to determine the best briquettes as implementation of wastes recycle based on scoring method, main component composition, compressive strength, caloric value, water content, vollatile content, and ash content, also the suitability with SNI 01-6235-2000. Main component that used are rice husk, 2mm and 6 mm PET, and dried leaves. Composition variation in this research are marked as K1, K2, K3, K4, and K5 with 2 mm PET plastic and K1, K2, K3, K4, and K5 with 6 mm PET plastic. The total weight of the briquettes is 100 g and divided into 90% main components and 10% tapioca as binder. The compressive strength, caloric value, water content, vollatile content, and ash content were tested according to ASTM D 5865-04, ASTM D 3173-03, ASTM D 3175-02, ASTM D 3174-02. The tested results were used to determine the best briquette by scoring method, and the chosen briquettes is K2 with 6 mm PET plastic. The composition is 70% rice husk, 20% 6 mm PET plastic, and 10% dried leaves with the compressive strength, caloric value, water content, vollatile content, and ash content value is 51,55 kg/cm2; 5123 kal/g; 3,049%; 31,823%, dan 12,869%. The suitable value that meet the criteria according to SNI 01-6235-2000 is compressive strength, caloric value, water content, and ash content.

  7. Removal of Ni(II), Zn(II) and Pb(II) ions from single metal aqueous solution using rice husk-based activated carbon

    SciTech Connect

    Taha, Mohd F. Shaharun, Maizatul S.; Shuib, Anis Suhaila Borhan, Azry

    2014-10-24

    An attempt was made to investigate the potential of rice husk-based activated carbon as an alternative low-cost adsorbent for the removal of Ni(II), Zn(II) and Pb(II) ions from single aqueous solution. Rice husk-based activated carbon was prepared via treatment of rice husk with NaOH followed by the carbonization process at 400°C for 2 hours. Three samples, i.e. raw rice husk, rice husk treated with NaOH and rice husk-based activated carbon, were analyzed for their morphological characteristics using field-emission scanning electron microscope/energy dispersive X-ray (FESEM/EDX). These samples were also analyzed for their carbon, hydrogen, nitrogen, oxygen and silica contents using CHN elemental analyzer and FESEM/EDX. The porous properties of rice husk-based activated carbon were determined by Brunauer-Emmett-Teller (BET) surface area analyzer, and its surface area and pore volume were 255 m{sup 2}/g and 0.17 cm{sup 2}/g, respectively. The adsorption studies for the removal of Ni(II), Zn(II) and Pb(II) ions from single metal aqueous solution were carried out at a fixed initial concentration of metal ion (150 ppm) with variation amount of adsorbent (rice husk-based activated carbon) as a function of varied contact time at room temperature. The concentration of each metal ion was analyzed using atomic absorption spectrophotometer (AAS). The results obtained from adsorption studies indicate the potential of rice husk as an economically promising precursor for the preparation of activated carbon for removal of Ni(II), Zn(II) and Pb(II) ions from single aqueous solution. Isotherm and kinetic model analyses suggested that the experimental data of adsorption studies fitted well with Langmuir, Freundlich and second-order kinetic models.

  8. Removal of Ni(II), Zn(II) and Pb(II) ions from single metal aqueous solution using rice husk-based activated carbon

    NASA Astrophysics Data System (ADS)

    Taha, Mohd F.; Shuib, Anis Suhaila; Shaharun, Maizatul S.; Borhan, Azry

    2014-10-01

    An attempt was made to investigate the potential of rice husk-based activated carbon as an alternative low-cost adsorbent for the removal of Ni(II), Zn(II) and Pb(II) ions from single aqueous solution. Rice husk-based activated carbon was prepared via treatment of rice husk with NaOH followed by the carbonization process at 400°C for 2 hours. Three samples, i.e. raw rice husk, rice husk treated with NaOH and rice husk-based activated carbon, were analyzed for their morphological characteristics using field-emission scanning electron microscope/energy dispersive X-ray (FESEM/EDX). These samples were also analyzed for their carbon, hydrogen, nitrogen, oxygen and silica contents using CHN elemental analyzer and FESEM/EDX. The porous properties of rice husk-based activated carbon were determined by Brunauer-Emmett-Teller (BET) surface area analyzer, and its surface area and pore volume were 255 m2/g and 0.17 cm2/g, respectively. The adsorption studies for the removal of Ni(II), Zn(II) and Pb(II) ions from single metal aqueous solution were carried out at a fixed initial concentration of metal ion (150 ppm) with variation amount of adsorbent (rice husk-based activated carbon) as a function of varied contact time at room temperature. The concentration of each metal ion was analyzed using atomic absorption spectrophotometer (AAS). The results obtained from adsorption studies indicate the potential of rice husk as an economically promising precursor for the preparation of activated carbon for removal of Ni(II), Zn(II) and Pb(II) ions from single aqueous solution. Isotherm and kinetic model analyses suggested that the experimental data of adsorption studies fitted well with Langmuir, Freundlich and second-order kinetic models.

  9. Determination of the intrinsic reactivities for carbon dioxide gasification of rice husk chars through using random pore model.

    PubMed

    Gao, Xiaoyan; Zhang, Yaning; Li, Bingxi; Zhao, Yijun; Jiang, Baocheng

    2016-10-01

    Rice husk is abundantly available and environmentally friendly, and char-CO2 gasification is of great importance for the biomass gasification process. The intrinsic reaction rates of carbon dioxide gasification with rice husk chars derived from different pyrolysis temperatures were investigated in this study by conducting thermogravimetric analysis (TGA) measurements. The effects of gasification temperature and reactant partial pressure on the char-CO2 gasification were investigated and the random pore model (RPM) was used to determine the intrinsic kinetic parameters based on the experimental data. The results obtained from this study show that the activation energy, reaction order and pre-exponential factor varied in the ranges of 226.65-232.28kJ/mol, 0.288-0.346 and 2.38×10(5)-2.82×10(5)1/sPa(n) for the rice husk chars pyrolyzed at 700-900°C, respectively. All the determination coefficients between the RPM predictions and experimental results were higher than 0.906, indicating the RPM is reliable for determining and evaluating the intrinsic reactivities of rice husk chars. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Separation of polysaccharides from rice husk and wheat bran using solvent system consisting of BMIMOAc and DMI.

    PubMed

    Hou, Qidong; Li, Weizun; Ju, Meiting; Liu, Le; Chen, Yu; Yang, Qian; Wang, Jingyu

    2015-11-20

    A solvent system consisting of 1,3-dimethyl-2-imidazolidinone (DMI), and ionic liquid 1-butyl-3-methylimidazolium acetate (BMIMOAc) was used to separate polysaccharides from rice husk and wheat bran. The effects of the DMI/BMIMOAc ratios, temperature, and time on the dissolution of rice husk and wheat bran were investigated, and the influence of anti-solvents on the regeneration of polysaccharides-rich material was evaluated. We found that the solvent system is more powerful to dissolve rice husk and wheat bran than pure BMIMOAc, and that polysaccharides-rich material can be effectively separated from the biomass solution. The polysaccharides content of regenerated material from wheat bran can reach as high as 94.4% when ethanol was used as anti-solvents. Under optimized conditions, the extraction rate of polysaccharides for wheat bran can reach as high as 71.8% at merely 50°C. The recycled solvent system exhibited constant ability to separate polysaccharides from rice husk and wheat bran. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Performance comparison of constructed wetlands with gravel- and rice husk-based media for phenol and nitrogen removal.

    PubMed

    Tee, H C; Seng, C E; Noor, A Md; Lim, P E

    2009-05-15

    This study aims to compare the performance of planted and unplanted constructed wetlands with gravel- and raw rice husk-based media for phenol and nitrogen removal. Four laboratory-scale horizontal subsurface-flow constructed wetland units, two of which planted with cattail (Typha latifolia) were operated outdoors. The units were operated at a nominal hydraulic retention time of 7 days and fed with domestic wastewater spiked with phenol concentration at 300 mg/L for 74 days and then at 500 mg/L for 198 days. The results show that planted wetland units performed better than the unplanted ones in the removal and mineralization of phenol. This was explained by the creation of more micro-aerobic zones in the root zone of the wetland plants which allow a faster rate of phenol biodegradation, and the phenol uptake by plants. The better performance of the rice husk-based planted wetland compared to that of the gravel-based planted wetland in phenol removal could be explained by the observation that more rhizomes were established in the rice husk-based wetland unit thus creating more micro-aerobic zones for phenol degradation. The role of rice husk as an adsorbent in phenol removal was considered not of importance.

  12. Evaluation of Mechanical Properties and Morphological Studies of Rice Husk (Treated/Untreated)-CaCO3 Reinforced Epoxy Hybrid Composites

    NASA Astrophysics Data System (ADS)

    Verma, Deepak; Joshi, Garvit; Gupta, Ayush

    2016-10-01

    Natural fiber reinforced composites are a very popular area of research because of the easy availability and biodegradability of these fibers. The manufacturing of natural fiber composite is done by reinforcing fibers in the particulate form, fiber form or in woven mat form. Natural fiber composites also utilize industrial wastes as a secondary reinforcements like fly ash, sludge etc. By keeping all these point of views in the present investigation the effect of rice husk flour (chemically treated/untreated) and micro sized calcium carbonate with epoxy resin have been evaluated. The diameter of rice husk flour was maintained at 600 µm through mechanical sieving machine. The husk flour was chemically treated with NaOH (5 % w/v). Mechanical properties like hardness, flexural impact and compression strength were evaluated and found to be superior in modified or chemically treated flour as compared to unmodified or untreated flour reinforced composites. Scanning electron microscopy (SEM) study was also undertaken for the developed composites. SEM study shows the distribution of the rice husk flour and calcium carbonate over the matrix.

  13. Recovery of silica from the gasification of rice husks/coal in the presence of a pilot flame in a modified fluidized bed

    SciTech Connect

    Luan, T.C.; Chou, T.C. )

    1990-09-01

    Combustion of rice husks with and without coal in the presence of a pilot flame in a modified fluidized bed was investigated in the present study. The process was employed to produce raw silica from rice husks by burning off other organic matters. The chemical and physical properties of both the top and the bottom products from the rice husk combustion were found to be strongly influenced by two major factors: the feed rate and the feed composition. It has also been found that coal fed along with rice husks to the combustion process permits easy control of the properties of both solid products and significantly reduces the agglomerating phenomena that occur often in the process. The temperature distribution of the fluidized bed, which reflects the bed operating characteristics, was measured and observed to depend on the frequency of pulsed solid feed.

  14. Effect of rice husk ash mass on sustainability pyrolysis zone of fixed bed downdraft gasifier with capacity of 10 kg/hour

    NASA Astrophysics Data System (ADS)

    Surjosatyo, Adi; Haq, Imaduddin; Dafiqurrohman, Hafif; Gibran, Felly Rihlat

    2017-03-01

    The formation of pyrolysis sustainability (Sustainable Pyrolysis) is the objective of the gasification process. Pyrolysis zone in the gasification process is the result of the endothermic reaction that get heat from oxidation (combustion) of the fuel with oxygen, where cracking biomass rice husk result of such as charcoal, water vapor, steam tar, and gas - gas (CO, H 2, CH 4, CO 2 and N 2) and must be maintained at a pyrolysis temperature to obtain results plentiful gas (producer gas) or syngas (synthetic gas). Obtaining continuously syngas is indicated by flow rate (discharge) producer gas well and the consistency of the flame on the gas burner, it is highly influenced by the gasification process and the operation of the gasifier and the mass balance (mass balance) between the feeding rate of rice husk with the disposal of ash (ash removal). In experiments conducted is using fixed bed gasifier type downdraft capacity of 10 kg/h. Besides setting the mass of rice husks into the gasifier and disposal arrangements rice husk ash may affect the sustainability of the pyrolysis process, but tar produced during the gasification process causes sticky rice husk ash in the plenum gasifier. Modifications disposal system rice husk ash can facilitate the arrangement of ash disposal then could control the temperature pyrolysis with pyrolysis at temperatures between 500-750 ° C. The experimental study was conducted to determine the effect of mass quantities of rice husk ash issued against sustainability pyrolysis temperature which is obtained at each time disposal of rice husk ash to produce 60-90 grams of ash issued. From some experimental phenomena is expected to be seen pyrolysis and its effect on the flow rate of syngas and the stability of the flame on the gas burner so that this research can find a correlation to obtain performance (performance) gasifier optimal.

  15. Homopiperazine grafted mesoporous silicas from rice husk ash for CO2 adsorption.

    PubMed

    Vinodh, Rajangam; Bhagiyalakshmi, Margandan; Hemalatha, Pushparaj; Ganesh, Mani; Peng, Mei Mei; Palanichamy, Muthiahpillai; Cha, Wang Seog; Jang, Hyun Tae

    2014-06-01

    Chloro-functionalized mesoporous MCM-41, SBA-15, MCM-48 and KIT-6 were synthesized by co-condensation of 3-chloropropyl-trimethoxy-silane (CPTMS) and rice husk ash sodium silicate solution, which is subsequently grafted with a heterocyclic amine, homopiperazine (HPZ). X-ray powder diffraction and BET analysis of the chloro-functionalized mesoporous silicas confirmed the similarity between their structural properties and those obtained from conventional silica sources. CO2 adsorption studies of all HPZ-grafted mesoporous silicas exhibited 8-10 wt% of adsorption capacity and are found to be selective, recyclable and thermally stable. Here, the CO2 adsorption reaction is via the traditional carbamate mechanism. The presence of both secondary and tertiary amine in HPZ influences the high CO2 adsorption capacity. Hence, these HPZ-grafted mesoporous silicas could contribute to CO2 capture as a green, tunable, selective and efficient sorbent.

  16. Preparation of TiO2/MCM-41 photocatalyst using rice husk ash as silica source

    NASA Astrophysics Data System (ADS)

    Fatimah, Is; Sopia, Lusi

    2017-03-01

    This work aimed to prepare TiO2/MCM-41 from rice husk ash (RHA) agricultural waste and its application as photocatalyst in dye degradation. The preparation was conducted by two main steps; preparation of MCM-41 and titanium immobilization onto MCM-41. Sol gel method using CTMABr as templating agent was applied in MCM-41 synthesis and as TiO2 precursor, titanium isopropoxide was utilized. The study of physicochemical character change was performed by by X-ray diffraction, IR spectroscopy, BET method and thermogravimetric analysis (TGA). Photocatalytic activity of material was tested in methylene blue photodegradation system. According to the results, it is found that TiO2/MCM-41 has been successfully prepared and shows photocatalytic activity. Kinetic study of the reaction is discussed in this paper.

  17. Effect of silica forms in rice husk ash on the properties of concrete

    NASA Astrophysics Data System (ADS)

    Bui, Le Anh-Tuan; Chen, Chun-Tsun; Hwang, Chao-Lung; Wu, Wei-Sheng

    2012-03-01

    The strength and durability properties of concrete with or without three types of rice husk ash (RHA), namely, amorphous, partial crystalline, and crystalline RHA, were investigates. The three types of RHA were added into concrete at a 20% replacement level. Consequently, the pozzolanic reactivity of amorphous RHA was higher than that of partial crystalline and crystalline RHA. Concrete added with amorphous RHA showed excellent characteristics in its mechanical and durability properties. The results showed that the higher the amount of crystalline silica in RHA, the lower the concrete resistivity value became. When compared with each other, concretes with 20% of the cement replaced with these types of RHA achieved similar ultrasonic pulse velocity values, but all were lower than that of the control concrete. The incorporation of these kinds of RHA significantly reduced chloride penetration. The results not only encourage the use of amorphous materials, they also support the application of crystalline or partial crystalline RHA as mineral and pozzolanic admixtures for cement.

  18. Utilization of rice husk silica as adsorbent for BTEX passive air sampler under high humidity condition.

    PubMed

    Areerob, Thanita; Grisdanurak, Nurak; Chiarakorn, Siriluk

    2016-03-01

    Selective adsorbent of benzene, toluene, ethylbenzene, and xylenes (BTEX) was developed based on mesoporous silica materials, RH-MCM-41. It was synthesized from rice husk silica and modified by silane reagents. The silane reagents used in this study were trimethylchlorosilane (TMS), triisopropylchlorosilane (TIPS), and phenyldimethylchlorosilane (PDMS). Physiochemical properties of synthesized materials were characterized by small-angle X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FTIR), and surface area analysis. Materials packed in passive air sampler were tested for BTEX uptake capacity. The tests were carried out under an influence of relative humidity (25 to 99 %). Overall, RH-MCM-41 modified by TMS outperformed compared to those modified by other silane agents. The comparative BTEX adsorption on this material and commercial graphitized carbon black was reported.

  19. Characterization, refining and antioxidant activity of saccharides derived from hemicelluloses of wood and rice husks.

    PubMed

    Rivas, Sandra; Conde, Enma; Moure, Andrés; Domínguez, Herminia; Parajó, Juan Carlos

    2013-11-01

    Samples of rice husks, Eucalyptus globulus wood and Pinus pinaster wood (containing arabinoxylan, acetylated glucuronoxylan and acetylated glucomannan as major hemicellulose components, respectively) were subjected to autohydrolysis. The resulting liquid phases, containing mainly hemicellulose-derived saccharides, were refined by physicochemical methods to reduce their contents of monosaccharides and non-saccharide compounds. Raw autohydrolysis liquors and refined concentrates coming from aqueous treatments were assayed for antioxidant activity using the following assays: reducing power (FRAP), DPPH and ABTS radical scavenging activity and protection of β-carotene-linoleic emulsions from oxidation. The reducing power and radical scavenging capacity of the non refined fractions were comparable to the ones determined for the reference compound butylhydroxytoluene. Hemicellulose concentrated from the different feedstocks and refining protocols showed a dose dependent antioxidant activity in the range of concentrations evaluated. The in vitro antioxidant activity of concentrates correlated with their phenolic content.

  20. Removal of dyes from aqueous solutions using activated carbon prepared from rice husk residue.

    PubMed

    Li, Yaxin; Zhang, Xian; Yang, Ruiguang; Li, Guiying; Hu, Changwei

    2016-01-01

    The treatment of dye wastewater by activated carbon (AC) prepared from rice husk residue wastes was studied. Batch adsorption studies were conducted to investigate the effects of contact time, initial concentration (50-450 mg/L), pH (3-11) and temperature (30-70 °C) on the removal of methylene blue (MB), neutral red, and methyl orange. Kinetic investigation revealed that the adsorption of dyes followed pseudo-second-order kinetics. The results suggested that AC was effective to remove dyes, especially MB, from aqueous solutions. Desorption studies found that chemisorption by the adsorbent might be the major mode of dye removal. Fourier transform infrared results suggested that dye molecules were likely to combine with the O-H and P=OOH groups of AC.

  1. Effects of volatile-char interactions on char during pyrolysis of rice husk at mild temperatures.

    PubMed

    Liu, Peng; Zhao, Yijun; Guo, Yangzhou; Feng, Dongdong; Wu, Jiangquan; Wang, Pengxiang; Sun, Shaozeng

    2016-11-01

    In order to understand the sensitivity of volatile-char interactions to mild temperatures (600-800°C), in-situ rice husk char was prepared from fast pyrolysis (>10(3)Ks(-1)) on a fixed-bed reactor. Retention of K in char, changes in char structure and char reactivity were determined. The results showed that volatile-char interactions did not cause obvious effect on the char yield but showed an inhibitory effect on char reactivity. The inhibition began only above 650°C and intensified with temperature rise, but kept almost unchanged at 700-800°C. Char structure and retention of K have a combined effect on char reactivity. The decreased reactivity was caused by additional volatilization of K from char matrix and transformation of relatively smaller aromatic ring systems to large ring systems (>6 benzene rings) above 650°C.

  2. Quantification of bioregeneration of activated carbon and activated rice husk loaded with phenolic compounds.

    PubMed

    Ng, S L; Seng, C E; Lim, P E

    2009-06-01

    The bioregeneration efficiencies of powdered activated carbon (PAC) and pyrolyzed rice husk loaded with phenol and p-nitrophenol were quantified by oxygen uptake measurements using the respirometry technique in two approaches: (i) simultaneous adsorption and biodegradation and (ii) sequential adsorption and biodegradation. It was found that the applicability of the simultaneous adsorption and biodegradation approach was constrained by the requirement of adsorption preceding biodegradation in order to determine the initial adsorbent loading accurately. The sequential adsorption and biodegradation approach provides a good estimate of the upper limit of the bioregeneration efficiency for the loaded adsorbent in the simultaneous adsorption and biodegradation processes. The results showed that the mean bioregeneration efficiencies for PAC loaded with phenol and p-nitrophenol, respectively, obtained using the two approaches were in good agreement.

  3. Physical and thermochemical characterization of rice husk char as a potential biomass energy source.

    PubMed

    Maiti, S; Dey, S; Purakayastha, S; Ghosh, B

    2006-11-01

    The fixed bed pyrolysis of rice husk was studied under conventional conditions with the aim of determining the characteristics of the charcoal formed for its applicability as a solid fuel. Thermoanalytic methods were used to determine the kinetic parameters of its combustion. Palletisation using different binders and techniques to improve the time of sustained combustion of the char pallets were investigated. The optimum temperature for carbonization to obtain a char having moderately high heating value was found as 400 degrees C. For the active char combustion zone, the order of reaction was nearly 1, the activation energy 73.403 kJ/mol and the pre-exponential factor 4.97 x 10(4)min(-1). Addition of starch as a binder and 10% ferrous sulphate heptahydrate or sodium hypophosphite as an additive enhanced the ignitibility of the char pallets.

  4. Synthesis and Characterization of Microwave Sintered Silica Xerogel Produced from Rice Husk Ash

    NASA Astrophysics Data System (ADS)

    Sudiana, I. N.; Mitsudo, S.; Nishiwaki, T.; Susilowati, P. E.; Lestari, L.; Firihu, M. Z.; Aripin, H.

    2016-08-01

    Silica xerogel ceramic produced from rice husk ash (RHA) taken from South East Sulawesi Indonesia has been successfully sintered by using a millimeter waves (MMW) heating system with a 28 GHz gyrotron as radiation source. The ceramic was also sintered by using an electric furnace where served as a comparison. Densification, microstructural, and morphological characterization of the silica were then investigated by using an Archimedes densification measurement method device, a X-ray diffraction (XRD) and a Scanning Electron Microscopy (SEM), respectively. Effect of microwave energy on the properties of silica xerogel ceramic were evaluated and discussed and compared to conventionally sintered results. The notably different densification and microstructure of sintered samples after sintering were found. The results suggest that microwave radiation provides a microwave effect during sintering.

  5. Synthesis and characterization of geopolymer from bottom ash and rice husk ash

    NASA Astrophysics Data System (ADS)

    Anggarini, Ufafa; Sukmana, Ndaru C.

    2016-02-01

    All Geopolymer (GP) has been synthesized from bottom ash and rice husk ash. This research aims to determine the effect of Si/Al ratio on geopolymer synthesis. Geopolymer was synthesized with various Si/Al ratio of 2, 3 and 4. The characterization result using XRD and SEM indicated that by using a different ratio of Si/A, it will produce geopolymer with varied structure and morphology. Diffractogram result shows that polymerization has been done for all samples (GP2, GP3, Gp4) with the presence of hump peak at 2θ = 27-35°. In GP4, no peak at 2θ = 18° indicating sodalite phase forming. Besides that, the morphology of geopolymer with a varied ratio of Si/Al shows that higher ratio will produce geopolymer with higher particle size. The highest compressive strength of geopolymer was obtained at a ratio of Si/Al = 4, with a maximum load of 12866 kgf.

  6. Ball milling synthesis of silica nanoparticle from rice husk ash for drug delivery application.

    PubMed

    Salavati-Niasari, Masoud; Javidi, Jaber; Dadkhah, Mahnaz

    2013-07-01

    Silica nanoparticles were synthesized from rice husk ash at room temperature by using high energy planetary ball mill. The milling time and mill rotational speed were varied in four levels. The morphology of the synthesized powders was investigated by the FE-SEM and TEM image as well as XRD patterns. The results have revealed that the nano-sized amorphous silica particles are formed after about 6 h ball milling and they are spherical in shape. The average particle size of the silica powders is found to be around 70 nm which decreases with increasing ball milling time or mill rotational speed. The as-synthesized silica nanoparticles were subsequently employed as drug carrier to investigate in vitro release behavior of Penicillin-G in simulated body fluid. UV-Vis spectroscopy was used to determine the amount of Penicillin-G released from the carrier. Penicillin-G release profile from silica nanoparticles exhibited a delayed release effect.

  7. Adsorption of sulfur compound utilizing rice husk ash modified with niobium

    NASA Astrophysics Data System (ADS)

    Cavalcanti, Rodrigo M.; Pessoa Júnior, Wanison A. G.; Braga, Valdeilson S.; Barros, Ivoneide de C. L.

    2015-11-01

    Adsorbents based in rice husk ash (RHA) modified with niobium pentoxide were prepared for impregnation methods and applied in sulfur removal in liquid fuels. The solids were characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, nitrogen physisorption and thermal analysis; they show that there was no qualitative change in the amorphous structure of the RHA; however, the method of impregnation could modify the particle size and topology of RHA particles. The larger sulfur removal (>50%) was achieved using RHA with 5 wt.% Nb2O5 at a dosage of 10 g L-1, after 4 h of contact with the model fuel. The kinetic study of adsorption of thiophene showed that the models of pseudo-second order and intra-particle diffusion best fit the experimental data. The adsorption experiments with the thiophenic derivatives compounds show a large selectivity of the adsorbent.

  8. A sustainable route for the preparation of activated carbon and silica from rice husk ash.

    PubMed

    Liu, Yan; Guo, Yupeng; Zhu, Yanchao; An, Dongmin; Gao, Wei; Wang, Zhuo; Ma, Yuejia; Wang, Zichen

    2011-02-28

    An environmentally friendly and economically effective process to produce silica and activated carbon form rice husk ask simultaneously has been developed in this study. An extraction yield of silica of 72-98% was obtained and the particle size was 40-50 nm. The microstructures of the as-obtained silica powders were characterized by X-ray diffraction (XRD) and infrared spectra (IR). The surface area, iodine number and capacitance value of activated carbon could achieve 570 m(2)/g, 1708 mg/g, 180 F/g, respectively. In the whole synthetic procedure, the wastewater and the carbon dioxide were collected and reutilized. The recovery rate of sodium carbonate was achieved 92.25%. The process is inexpensive, sustainable, environmentally friendly and suitable for large-scale production.

  9. Biodiesel production from waste cooking oil using a heterogeneous catalyst from pyrolyzed rice husk.

    PubMed

    Li, Ming; Zheng, Yan; Chen, Yixin; Zhu, Xifeng

    2014-02-01

    A solid acid catalyst was prepared by sulfonating pyrolyzed rice husk with concentrated sulfuric acid, and the physical and chemical properties of the catalyst were characterized in detail. The catalyst was then used to simultaneously catalyze esterification and transesterification to produce biodiesel from waste cooking oil (WCO). In the presence of the as-prepared catalyst, the free fatty acid (FFA) conversion reached 98.17% after 3h, and the fatty acid methyl ester (FAME) yield reached 87.57% after 15 h. By contrast, the typical solid acid catalyst Amberlyst-15 obtained only 95.25% and 45.17% FFA conversion and FAME yield, respectively. Thus, the prepared catalyst had a high catalytic activity for simultaneous esterification and transesterification. In addition, the catalyst had excellent stability, thereby having potential use as a heterogeneous catalyst for biodiesel production from WCO with a high FFA content. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Effects of water washing and torrefaction on the pyrolysis behavior and kinetics of rice husk through TGA and Py-GC/MS.

    PubMed

    Zhang, Shuping; Dong, Qing; Zhang, Li; Xiong, Yuanquan

    2016-01-01

    The effects of water washing and torrefaction on the pyrolysis behavior and kinetics of rice husk were investigated through TGA and Py-GC/MS in this study. Two iso-conversional methods, i.e. Starink and FWO methods were applied for determination of the activation energy of original and pretreated rice husk samples at three different heating rates. It was found that activation energy of water washed rice husk was lower than that of original rice husk. Whereas, the activation energy increased with the increase of torrefaction temperature. The result of Py-GC/MS analysis indicated that both water washing and torrefaction pretreatments decreased the contents of acids, ketones, aldehydes and furans, while significantly increased the contents of sugars, especially levoglucosan. The relative content of released levoglucosan from pyrolysis of rice husk sample with combined water washing and 280°C torrefaction pretreatment is almost 9 times of that from original rice husk, which is about 3%. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Enzymatic degradation of poly-butylene succinate-co-adipate film in rice husks by yeast Pseudozyma antarctica in indoor conditions.

    PubMed

    Kitamoto, Hiroko; Yoshida, Shigenobu; Koitabashi, Motoo; Yamamoto-Tamura, Kimiko; Ueda, Hirokazu; Yarimizu, Tohru; Sameshima-Yamashita, Yuka

    2017-09-22

    Agricultural mulch films made from biodegradable polymers (BP) have been used to decrease the burden of plastic waste recovery and recycling. However, their degradations depend largely on environmental conditions and sometimes do not proceed as desired. Yeast strains of Pseudozyma antarctica often isolated from rice husks were found to secrete an esterase to degrade BP films. Poly-butylene succinate-co-adipate (PBSA) films buried in unsterilized rice husks with 60% (w/w) moisture degraded rapidly compared to that buried in field soil. The type strain of P. antarctica JCM 10317 added as cell suspension onto sterilized rice husks with PBSA film grew rapidly forming filamentous growth on the surface of rice husks and films. BP-degrading enzyme secreted by the growing cells was adsorbed on the surface of film and decomposed the film. Addition of rice husk-derived P. antarctica strains also showed BP film degradation activity in sterilized rice husks. In the light of these findings, we suggest that techniques for disposal of used BPs which combine plastics with unutilized residual plant materials piled at the side of agricultural fields be developed. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  12. Silica-tin nanotubes prepared from rice husk ash by sol-gel method: Characterization and its photocatalytic activity

    NASA Astrophysics Data System (ADS)

    Adam, Farook; Appaturi, Jimmy Nelson; Thankappan, Radhika; Nawi, Mohd Asri Mohd

    2010-11-01

    Silica-tin material has been synthesized by simple sol-gel method using rice husk ash as the source of silica and cetyltrimethylammonium bromide as the surfactant at room temperature. Calcination of the material at 500 °C for 5 h gave nanotubes with external diameter of 2-4 nm and an internal diameter of 1-2 nm. The BET specific surface area was found to be 607 m 2 g -1. Nitrogen sorption analysis exhibits a type IV isotherm with H3 hysteresis loop. The powder X-ray diffraction pattern showed that the material is amorphous. The photocatalytic activity of the prepared material was studied towards degradation of methylene blue under UV-irradiation. According to the experimental results the silica-tin nanotubes exhibit high photocatalytic activity compared to pure rice husk silica.

  13. Effect of silicate-based corrosion inhibitor from rice husk ash on aluminum alloy in 0.5M HCl

    NASA Astrophysics Data System (ADS)

    Othman, N. K.; Mohamad, N.; Zulkafli, R.; Jalar, A.

    2013-05-01

    Silicate-based corrosion inhibitor prepared by treating silica powder extracted from rice husk ash with concentrated alkaline. The electrochemical behavior of the Al 6061 immersed in 0.5 M hydrochloric acid (HCl) has been studied using the measurements of weight loss, potentiodynamic polarization and optical or scanning electron microscopy (SEM). It was found that, the optimum concentration of silicate-based corrosion inhibitor was prominent at 5 ppm. The small addition of silicate-based corrosion inhibitor was exhibited the decreasing of the weight loss of Al 6061 in acidic medium. SEM micrograph proved that the morphology of untreated Al 6061 with silicate-base corrosion inhibitor contributes more corrosion attack on sample compared to that treated Al 6061. The purpose of this research is to understand the effect of silicate-based corrosion inhibitor concentration yielded from rice husk ash on aluminum alloy.

  14. Experimental study on rice husk combustion in a vortexing fluidized-bed with flue gas recirculation (FGR).

    PubMed

    Duan, Feng; Chyang, Chien-Song; Lin, Chien-Wei; Tso, Jim

    2013-04-01

    Vortexing fluidized-bed combustor (VFBC) has been proven to be an effective equipment in converting biomass wastes into clean energy. This study conducted experiments on rice husk combustion in a VFBC with FGR. The effect of FGR on combustion characteristics is investigated. In addition, the effect of operating variables such as excess oxygen ratio, and in-bed stoichiometric oxygen ratio on the temperature distributions, pollutants emissions, and combustion efficiency are also studied. The results show that the combustion efficiency of rice husk can reach 99% at optimal operation condition. CO emission increases with the in-bed stoichiometric oxygen ratio, but decreases with excess oxygen ratio. NOx emissions show inverse trend, and it can be effectively reduced by using FGR in the VFBC.

  15. Electrostatic separation of mineral and vegetal powders with a custom built corona separator: application to biorefinery of rice husk

    NASA Astrophysics Data System (ADS)

    Rajaonarivony, Rova Karine; Rouau, Xavier; Dascalescu, Lucien; Mayer-Laigle, Claire

    2017-06-01

    In a dry biorefinery scheme, the separation of plant materials into powders rich in the constituents of interest is a crucial step. In recent years, electrostatic separation of agri-resources has sparked a growing interest for its potentialities, but optimization efforts remain to be done especially in case of fine powders. In this study a custom-designed corona-electrostatic separator has been built and its usage for the separation of mineral (ash from rice husk) and vegetal powders (cellulose fibers) with different particle size distributions has been studied. First, the powders have been characterized by their electric charge decay curves and their behaviour on the separator was studied. At a second time, separation tests have been carried out with blends of these two powders, and with native, finely ground, rice husk powder (constituted of both mineral and vegetal particles). In each case, the efficiency of the process was evaluated.

  16. Optimization of high filler loading on tensile properties of recycled HDPE/PET blends filled with rice husk

    NASA Astrophysics Data System (ADS)

    Chen, Ruey Shan; Ahmad, Sahrim; Ghani, Mohd Hafizuddin Ab; Salleh, Mohd Nazry

    2014-09-01

    Biocomposites of recycled high density polyethylene / recycled polyethylene terephthalate (rHDPE/rPET) blend incorporated with rice husk flour (RHF) were prepared using a corotating twin screw extruder. Maleic anhydride polyethylene (MAPE) was added as a coupling agent to improve the fibre-matrix interface adhesion. The effect of high filler loadings (50-90 wt%) on morphology and tensile properties of compatibilized rHDPE/rPET blend was investigated. The results of our study shown that composite with 70 wt% exhibited the highest tensile strength and Young's modulus, which are 22 MPa and 1752 MPa, respectively. The elongation at break decreased with increasing percentage of RHF. SEM micrograph confirmed fillers dispersion, morphological interaction and enhanced interfacial bonding between recycled polymer blends and rice husk. It can be concluded that the optimum RHF content is 70 wt% with maximum tensile strength.

  17. Effect of black rice husk ash on the physical and rheological properties of bitumen

    NASA Astrophysics Data System (ADS)

    Romastarika, Raissa; Jaya, Ramadhansyah Putra; Yaacob, Haryati; Nazri, Fadzli Mohamed; Agussabti, Ichwana, Jayanti, Dewi Sri

    2017-08-01

    Black rice husk ash (BRHA) waste product is inexpensive and can be obtained from rice mills. Reuse of waste product is ideal to reduce pollution, because disposal is decreased or eliminated. The commercial value of BRHA has increased, and it is suitable for use in road construction. In this study, BRHA waste was ground using a grinding ball mill for 120 min to form fine powder. BRHA was then sieved to less than 75 µm. At the laboratory, BRHA was mixed with bitumen to replace 2%, 4%, and 6% of the total weight, whereas 0% represented the control sample. The penetration, softening point, dynamic shear rheometer (DSR) and rolling thin film oven (RTFO) were investigated in this study. Results showed that bitumen became harder, whereas the rate of penetration decreased when the replacement amount of BRHA increased. Softening point test of bitumen also revealed an increase. The short-term aging test revealed that modification of bitumen could relieve the effect of aging. BRHA waste added into bitumen improved the performance of bitumen. Therefore, the usage of BRHA could help improve the performance of road pavement and reduce the rutting effect.

  18. Carbon materials derived from rice husks at low and high temperatures

    NASA Astrophysics Data System (ADS)

    Melvin, G. J. H.; Wang, Z.; Siambun, N. J.; Rahman, M. M.

    2017-07-01

    Rice husk (RH) can be classified as an agriculture residue, majorly produced from by-product of rice milling industries. However, RHs are only mainly utilized for low value energy resource. A great number of researches and innovations have shown that heat treated RHs can turn into valuable carbon materials. In this study, the RHs were carbonized at 800°C and 2500°C, respectively. Their structure, morphology, elemental composition, and quality were characterized using transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. The carbon materials obtained from low and high temperature carbonization processes showed different characteristics. High purity and crystallinity of carbon materials were obtained from RHs carbonized at 2500°C. Furthermore, from Raman results, RHs carbonized at 2500°C exhibited low D/G ratio. This further reveals that the RHs carbonized at 2500°C possess minimal defects. The unique characteristics of RHs carbonized at high temperature indicate that they could be a promising material to be utilized in particular or various applications.

  19. Microbial Biotreatment of Actual Textile Wastewater in a Continuous Sequential Rice Husk Biofilter and the Microbial Community Involved

    PubMed Central

    Lindh, Markus V.; Pinhassi, Jarone; Welander, Ulrika

    2017-01-01

    Textile dying processes often pollute wastewater with recalcitrant azo and anthraquinone dyes. Yet, there is little development of effective and affordable degradation systems for textile wastewater applicable in countries where water technologies remain poor. We determined biodegradation of actual textile wastewater in biofilters containing rice husks by spectrophotometry and liquid chromatography mass spectrometry. The indigenous microflora from the rice husks consistently performed >90% decolorization at a hydraulic retention time of 67 h. Analysis of microbial community composition of bacterial 16S rRNA genes and fungal internal transcribed spacer (ITS) gene fragments in the biofilters revealed a bacterial consortium known to carry azoreductase genes, such as Dysgonomonas, and Pseudomonas and the presence of fungal phylotypes such as Gibberella and Fusarium. Our findings emphasize that rice husk biofilters support a microbial community of both bacteria and fungi with key features for biodegradation of actual textile wastewater. These results suggest that microbial processes can substantially contribute to efficient and reliable degradation of actual textile wastewater. Thus, development of biodegradation systems holds promise for application of affordable wastewater treatment in polluted environments. PMID:28114377

  20. Environmentally-Friendly Dense and Porous Geopolymers Using Fly Ash and Rice Husk Ash as Raw Materials

    PubMed Central

    Ziegler, Daniele; Formia, Alessandra; Tulliani, Jean-Marc; Palmero, Paola

    2016-01-01

    This paper assesses the feasibility of two industrial wastes, fly ash (FA) and rice husk ash (RHA), as raw materials for the production of geopolymeric pastes. Three typologies of samples were thus produced: (i) halloysite activated with potassium hydroxide and nanosilica, used as the reference sample (HL-S); (ii) halloysite activated with rice husk ash dissolved into KOH solution (HL-R); (iii) FA activated with the alkaline solution realized with the rice husk ash (FA-R). Dense and porous samples were produced and characterized in terms of mechanical properties and environmental impact. The flexural and compressive strength of HL-R reached about 9 and 43 MPa, respectively. On the contrary, the compressive strength of FA-R is significantly lower than the HL-R one, in spite of a comparable flexural strength being reached. However, when porous samples are concerned, FA-R shows comparable or even higher strength than HL-R. Thus, the current results show that RHA is a valuable alternative to silica nanopowder to prepare the activator solution, to be used either with calcined clay and fly ash feedstock materials. Finally, a preliminary evaluation of the global warming potential (GWP) was performed for the three investigated formulations. With the mix containing FA and RHA-based silica solution, a reduction of about 90% of GWP was achieved with respect to the values obtained for the reference formulation. PMID:28773587

  1. Effect of organic calcium compounds on combustion characteristics of rice husk, sewage sludge, and bituminous coal: thermogravimetric investigation.

    PubMed

    Zhang, Lihui; Duan, Feng; Huang, Yaji

    2015-04-01

    Experiments were conducted in a thermogravimetric analyzer to assess the enhancement of combustion characteristics of different solid fuels blended with organic calcium compounds (OCCs). Rice husk, sewage sludge, and bituminous coal, and two OCC were used in this study. Effect of different mole ratios of calcium to sulfur (Ca/S ratio) on the combustion characteristics were also investigated. Results indicated that combustion performance indexes for bituminous coal impregnated by OCC were improved, however, an inverse trend was found for sewage sludge because sewage sludge has lower ignition temperature and higher volatile matter content compared to those of OCC. For rice husk, effect of added OCC on the combustion characteristics is not obvious. Different solid fuels show different combustion characteristics with increases of Ca/S ratio. The maximum combustion performance indexes appear at Ca/S ratios of 1:1, 2:1, and 3:1 for OCC blended with Shenhua coal, rice husk, and sewage sludge, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Characteristics of microporous/mesoporous carbons prepared from rice husk under base- and acid-treated conditions.

    PubMed

    Liou, Tzong-Horng; Wu, Shao-Jung

    2009-11-15

    The study reports the preparation of activated carbon with a high surface area from rice husk using chemical activation with H(3)PO(4) and ZnCl(2). Activated carbon prepared from rice husk usually exhibits low specific surface areas due to its high ash content. However, experimental results show that base-leaching and acid-washing processes can effectively enhance the adsorption capacity of rice-husk carbon. The study also investigates the effects of preparation parameters on the surface characteristics of the carbon. These parameters include the kind of activating agent, before and after treatment procedures, impregnation ratio and activation temperature. The chemical and physical properties of samples were examined by EA, ICP-MS, XRD, FTIR, SEM and a N(2)-adsorption meter. The surface areas obtained from ZnCl(2) and H(3)PO(4) activation are as high as 2434 and 1741 m(2)/g, respectively. These values are higher than that of activated carbon treated with neither base nor acid (1262 and 508 m(2)/g for ZnCl(2) and H(3)PO(4) activation). Thermogravimetric analysis shows that the activation process can be divided into three parts based on temperature zones. The results of this study will be useful in developing resource recovery systems for agricultural biomass.

  3. Utilization of rice husk waste for Cd(II) adsorbent and its analysis using solid-phase spectrophotometry (sps)

    NASA Astrophysics Data System (ADS)

    Saputro, S.; Masykuri, M.; Mahardiani, L.; Arini, S.; Ramelan, A. H.

    2017-04-01

    This research aims to know the use of rice husk waste for metal ion adsorbent of Cd(II), the optimum mass which are needed, the sensitivity of SPS as a method to determine the reduction level of Cd(II) metal ions in the level of μg/L. This research was conducted by using an experimental method in the laboratory. The used adsorbent in this research is rice husk charcoal which activated using ZnCl2 10% solution. Determination of the optimum adsorbent mass was done with reacted 0.5; 1.0; 1.5; 2.0; and 2.5 g of adsorbent and 20 mL Cd(II) which have concentration 75.27 μg/L during 30 minutes. Analysis the levels of Cd(II) used SPS method and characterization of adsorbent used FTIR. The result showed that activated rice husk charcoal can be used as adsorbent for Cd(II) metal ions in the simulated liquid waste with the adsorption capacity of 0.58 μg/g, the optimum mass was 2.0 gram with percentage of the adsorbed Cd(II) of 77.87%, SPS is a sensitive method to determine the reduction levels of Cd(II) metal ions in the level of μg/L with the limit of detection (LOD) was 0.06 μg/L.

  4. Synthesis of Na-A and/or Na-X zeolite/porous carbon composites from carbonized rice husk

    NASA Astrophysics Data System (ADS)

    Katsuki, Hiroaki; Komarneni, Sridhar

    2009-07-01

    Na-A and/or Na-X zeolite/porous carbon composites were prepared under hydrothermal conditions by NaOH dissolution of silica first from carbonized rice husk followed by addition of NaAlO 2 and in situ crystallization of zeolites i.e., using a two-step process. When a one-step process was used, both Na-A and Na-X zeolites crystallized on the surface of carbon. Na-A or Na-X zeolite crystals were prepared on the porous carbonized rice husk at 90 °C for 2-6 h by changing the SiO 2/Al 2O 3, H 2O/Na 2O and Na 2O/SiO 2 molar ratios of precursors in the two-step process. The surface area and NH 4+-cation exchange capacity (CEC) of Na-A zeolite/porous carbon were found to be 171 m 2/g and 506 meq/100 g, respectively, while those of Na-X zeolite/porous carbon composites were 676 m 2/g and 317 meq/100 g, respectively. Na-A and Na-X zeolites are well-known microporous and hydrophilic materials while carbonized rice husk was found to be mesoporous (pores of ˜3.9 nm) and hydrophobic. These hybrid microporous-mesoporous and hydrophilic-hydrophobic composites are expected to be useful for decontamination of metal cations as well as organic contaminants simultaneously.

  5. Microbial Biotreatment of Actual Textile Wastewater in a Continuous Sequential Rice Husk Biofilter and the Microbial Community Involved.

    PubMed

    Forss, Jörgen; Lindh, Markus V; Pinhassi, Jarone; Welander, Ulrika

    2017-01-01

    Textile dying processes often pollute wastewater with recalcitrant azo and anthraquinone dyes. Yet, there is little development of effective and affordable degradation systems for textile wastewater applicable in countries where water technologies remain poor. We determined biodegradation of actual textile wastewater in biofilters containing rice husks by spectrophotometry and liquid chromatography mass spectrometry. The indigenous microflora from the rice husks consistently performed >90% decolorization at a hydraulic retention time of 67 h. Analysis of microbial community composition of bacterial 16S rRNA genes and fungal internal transcribed spacer (ITS) gene fragments in the biofilters revealed a bacterial consortium known to carry azoreductase genes, such as Dysgonomonas, and Pseudomonas and the presence of fungal phylotypes such as Gibberella and Fusarium. Our findings emphasize that rice husk biofilters support a microbial community of both bacteria and fungi with key features for biodegradation of actual textile wastewater. These results suggest that microbial processes can substantially contribute to efficient and reliable degradation of actual textile wastewater. Thus, development of biodegradation systems holds promise for application of affordable wastewater treatment in polluted environments.

  6. Characteristics and oil sorption effectiveness of kapok fibre, sugarcane bagasse and rice husks: oil removal suitability matrix.

    PubMed

    Ali, Norizan; El-Harbawi, Mohanad; Jabal, Ayman Abo; Yin, Chun-Yang

    2012-01-01

    The characteristics and water/oil sorption effectiveness ofkapok fibre, sugarcane bagasse and rice husks have been compared. The three biomass types were subjected to field emission scanning electron microscopy-energy dispersive X-ray spectroscopy and surface tension analyses for liquid-air and oil-water systems were conducted. Both kapok fibre and sugarcane bagasse exhibit excellent oil sorption capabilities for diesel, crude, new engine and used engine oils as their oil sorption capacities all exceed 10 g/g. The synthetic sorbent exhibits oil sorption capacities comparable with sugarcane bagasse, while rice husks exhibit the lowest oil sorption capacities among all the sorbents. Kapok fibre shows overwhelmingly high oil-to-water sorption (O/W) ratios ranging from 19.35 to 201.53 while sugarcane bagasse, rice husks and synthetic sorbent have significantly lower O/W ratios (0.76-2.69). This suggests that kapok fibre is a highly effective oil sorbent even in well-mixed oil-water media. An oil sorbent suitability matrix is proposed to aid stakeholders in evaluating customized oil removal usage of the natural sorbents.

  7. Adsorption and detection of some phenolic compounds by rice husk ash of Kenyan origin.

    PubMed

    Mbui, Damaris N; Shiundu, Paul M; Ndonye, Rachel M; Kamau, Geoffrey N

    2002-12-01

    Rice husk ash (RHA) obtained from a rice mill in Kenya has been used as an inexpensive and effective adsorbent (and reagent) for the removal (and detection) of some phenolic compounds in water. The abundantly available rice mill waste was used in dual laboratory-scale batch experiments to evaluate its potential in: (i) the removal of phenol, 1,3-dihydroxybenzene (resorcinol) and 2-chlorophenol from water; and (ii) the detection of 1,2-dihydroxybenzene (pyrocatechol) and 1,2,3-trihydroxybenzene (pyrogallol) present in an aqueous medium. The studies were conducted using synthetic water with different initial concentrations of the phenolic compounds. The effects of different operating conditions (such as contact time, concentration of the phenolic compounds, adsorbent quantity, temperature, and pH) were assessed by evaluating the phenolic compound removal efficiency as well as the extent of their color formation reactions (where applicable). RHA exhibits reasonable adsorption capacity for the phenolic compounds and follows both Langmuir and Freundlich isotherm models. Adsorption capacities of 1.53 x 10(-4), 8.07 x 10(-5), and 1.63 x 10(-6) mol g(-1) were determined for phenol, resorcinol and 2-chlorophenol, respectively. Nearly 100% adsorption of the phenolic compounds was possible and this depended on the weight of RHA employed. For the detection experiments, pyrocatechol and pyrogallol present in water formed coloured complexes with RHA, with the rate of colour formation increasing with temperature, weight of RHA, concentration of the phenolic compounds and sonication. This study has proven that RHA is a useful agricultural waste product for the removal and detection of some phenolic compounds.

  8. Use of the rice husk as an alternative substrate for growing media on green walls drip irrigation

    NASA Astrophysics Data System (ADS)

    Andrey Rivas-Sánchez, Yair; Fátima Moreno-Pérez, María; Roldán Cañas, José

    2017-04-01

    In the last years, we have been looking for alternatives to traditional growing mediums for green walls. Commercially available systems for green walls are commonly made with Sphagnum, rock wool or polymers that are unsustainable materials. In the design of the green wall, local components such as agricultural by-products should be considered more often. The objective of this research is to use alternative materials available in Andalusia that are suitable for use as a growing medium in green walls, using organic residues generated by agriculture as in this case the rice husk, compared to conventional and used materials as a growing media in green walls such as coconut fiber and rock wool. The physical-chemical characteristics of the water were analyzed through the collection of excess irrigation water, after passing through the prototypes of green walls, installed in the Rabanales Campus of the University of Córdoba between April and July 2016 and thus observe the feasibility of using rice husk as an alternative material. The 16 mm diameter irrigation pipes are at the top and middle of each module, with 12 adjustable drippers of 4 l / h for each module, 72 drippers in the whole experimental green wall prototype installed at every 15 centimeters of tube. Two different species of plant material (Lampranthus spectabilis) and (Lavandula stoechas), were selected, taking into account the solar exposition of the place of establishment of the prototype of the green wall and the easy acquisition of these plants in the region. Water samples were collected every day twice a day for 10 weeks of the experiment, taking a sample of the surplus runoff water from six green wall prototypes.PH 40 - pH - conductivity - TDS - temperature, CRISON. Differences in pH, electrical conductivity, turbidity and total solids of the treatments were examined by ANOVA with the test of normality and homogeneity of variances. It was observed that the substrates used in the prototypes of the

  9. Investigation on hardness and impact resistance of automotive brake pad composed with rice husk dust

    NASA Astrophysics Data System (ADS)

    Bahari, Shahril Anuar; Isa, Khairul Hafizee; Kassim, Masitah Abu; Mohamed, Zulkifli; Othman, Eliasidi Abu

    2012-06-01

    In this study, hardness and impact resistance properties of automotive brake pad composed with rice husk dust (RHD) were documented. RHD was mixed with other metallic and synthetic ingredients of automotive brake pad. To obtain RHD, rice husk was ground and dried to 1 - 3% moisture content. The RHD was screened to obtain different dust sizes (80 and 100-mesh) before it was mixed with other materials at different percentages of composition (10 and 30%). The mixture was then pressed to produce brake pad. Rockwell hardness testing machine was used in hardness determination, while Izod impact testing machine was used in impact resistance determination. Hardness resistance of automotive brake pad mixed with 10% composition and 80-mesh size of RHD was significantly higher than 100-mesh. Hardness resistance of automotive brake pad mixed with 30% composition and 100-mesh size of RHD was slightly higher than 80 mesh. However, based on analysis, the difference was not significant. According to the result, hardness resistance of automotive brake pad mixed with 30% composition of RHD was higher than 10%. RHD has filled up the space and enhanced the micro structural behaviour of automotive brake pad. Impact resistance of automotive brake pad mixed with 10% composition and 80-mesh size of RHD was insignificantly higher than 100-mesh. Impact resistance of automotive brake pad mixed with 30% composition and 80-mesh size of RHD was significantly higher than 100 mesh. Large RHD size has increased the capability to resist high-rated impact loading. The impact energy was distributed over wider area for larger particle size. This factor has increased the impact resistance of automotive brake pad from large dust size. Impact resistance of automotive brake pad mixed with 80-mesh size and 30% composition of RHD was higher than 10%. In contrast, impact resistance of automotive brake pad mixed with 100-mesh size and 10% composition of RHD was higher than 30%. However, the difference was not

  10. Effects of rice husks and their chars from hydrothermal carbonization on the germination rate and root length of Lepidium sativum

    NASA Astrophysics Data System (ADS)

    Kern, Jürgen; Mukhina, Irina; Dicke, Christiane; Lanza, Giacomo; Kalderis, Dimitrios

    2015-04-01

    Currently, char substrates gain a lot of interest, since they are being discussed as a component in growing media, which may become one option for the replacement of peat. Among different thermal conversion processes of biomass hydrothermal carbonization (HTC) has been found to produce chars with similar acidic pH values like peat. The question however is, if these hydrochars, which may contain toxic phenolic compounds are suitable to be introduced as a new substitute for peat in horticulture. In this study rice husk were hydrothermally carbonized at 200° C for 6 hours, yielding in hydrochars containing organic contaminants such as phenols and furfurals, which may affect plants and soil organisms. We investigated potential toxic effects on the germination rate and the root length of cress salad (Lepidium sativum) in four fractions: i) soil control, ii) raw rice husk + soil, iii) unwashed rice char + soil and iv) acetone/water washed rice char + soil. It could be shown that phenols and furfurals, which were removed from the hydrochar after washing by 80 to 96% did not affect the germination rate and the root length of the cress plants. The lowest germination rate and root length were found in the soil control, the highest in the non-washed hydrochar treatment, indicating a fertilization effect and growth stimulation of cress salad by hydrochar. If this result can be confirmed for other target and non-target organisms in future studies, a new strategy for the production of growing media may be developed.

  11. Nano-silicate inhibitor derived from rice husk for corrosion mitigation of steel in distilled water

    NASA Astrophysics Data System (ADS)

    Asra, Denni; Othman, Norinsan Kamil; Dasuki, Zulhusni

    2017-05-01

    Nanosilicate extracts from rice husk (Oryza sativa L.) ash (RHA) as a corrosion inhibitor for carbon steel in distilled water has been investigated. The nanosilicates extracted from RHA was obtained through wet chemical extraction and the extracted nanosilicates powder were analyzed using Fourier Transform Infrared Spectroscopy (FTIR) in order to identify the presence of functional groups (SiO2) that contributed to the inhibition process. The particle size of extracted nanosilica is in the range of 5-10 nm and it was confirmed through Transmission electron microscopy (TEM) and Zeta Sizer analysis. The corrosion measurement study on the effect of nanosilicate from RHA on carbon steel samples in distilled water as corrosive media had been conducted by employing weight loss method, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), surface analysis, and adsorption isotherm study. It was proven that the maximum inhibition efficiency (IE %) obtained through corrosion measurement were up to 98 % of inhibition. On the other hand, the adsorption of inhibitor on the carbon steel surface was found to follow Temkin isotherm. Based on the result of potentiodynamic polarization, it showed that inhibitors are mixed type. The results of EIS showed that value of charge transfer resistance and the percentage of inhibition efficiency increased with the increasing of nanosilicate concentration. Surface analysis on specimen that was treated with nanosilicate were smoother with fewer corrosion products compared to untreated specimen.

  12. Possibility of sludge conditioning and dewatering with rice husk biochar modified by ferric chloride.

    PubMed

    Wu, Yan; Zhang, Panyue; Zhang, Haibo; Zeng, Guangming; Liu, Jianbo; Ye, Jie; Fang, Wei; Gou, Xiying

    2016-04-01

    Rice husk biochar modified by FeCl3 (MRB-Fe) was used to enhance sludge dewaterability in this study. MRB-Fe preparation conditions and dosage were optimized. Mechanisms of MRB-Fe improving sludge dewaterability were investigated. The optimal modification conditions were: FeCl3 concentration, 3mol/L; ultrasound time, 1h. The optimal MRB-Fe dosage was 60% DS. Compared with raw sludge, the sludge specific resistance to filtration (SRF) decreased by 97.9%, the moisture content of sludge cake decreased from 96.7% to 77.9% for 6min dewatering through vacuum filtration under 0.03MPa, the SV30% decreased from 96% to 60%, and the net sludge solids yield (YN) increased by 28 times. Positive charge from iron species on MRB-Fe surface counteracted negative charge of sludge flocs to promote sludge settleability and dewaterability. Meanwhile, MRB-Fe kept a certain skeleton structure in sludge cake, making the moisture pass through easily. Using MRB-Fe, therefore, for sludge conditioning and dewatering is promising. Copyright © 2016. Published by Elsevier Ltd.

  13. Pollutant emission characteristics of rice husk combustion in a vortexing fluidized bed incinerator.

    PubMed

    Duan, Feng; Chyang, Chiensong; Chin, Yucheng; Tso, Jim

    2013-02-01

    Rice husk with high volatile content was burned in a pilot scale vortexing fluidized bed incinerator. The fluidized bed incinerator was constructed of 6 mm stainless steel with 0.45 m in diameter and 5 m in height. The emission characteristics of CO, NO, and SO2 were studied. The effects of operating parameters, such as primary air flow rate, secondary air flow rate, and excess air ratio on the pollutant emissions were also investigated. The results show that a large proportion of combustion occurs at the bed surface and the freeboard zone. The SO2 concentration in the flue gas decreases with increasing excess air ratio, while the NOx concentration shows reverse trend. The flow rate of secondary air has a significant impact on the CO emission. For a fixed primary air flowrate, CO emission decreases with the secondary air flowrate. For a fixed excess air ratio, CO emission decreases with the ratio of secondary to primary air flow. The minimum CO emission of 72 ppm is attained at the operating condition of 40% excess air ratio and 0.6 partition air ratio. The NOx and SO2 concentrations in the flue gas at this condition are 159 and 36 ppm, which conform to the EPA regulation of Taiwan.

  14. Steam reforming of bio-oil from rice husks fast pyrolysis for hydrogen production.

    PubMed

    Chen, Tianju; Wu, Ceng; Liu, Ronghou

    2011-10-01

    Steam reforming of two kinds of bio-oil from rice husks fast pyrolysis was conducted for hydrogen production at three temperatures (650, 750 and 850 °C) with Ni-based catalyst in a fixed-bed reactor. The gas composition and organic compounds in liquid condensate were detected by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS), respectively. In addition, the carbon deposition was also investigated. The results showed that the mole fraction range of hydrogen was within 55.8-61.3% at all temperatures and more hydrogen was produced at the higher temperature. The highest H₂ efficiency of bio-oil steam reforming was 45.33% when extra water was added. The bio-oil with lower content of chemical compounds has a higher H₂ efficiency, but its hydrogen volume was less. Analysis of the liquid condensate showed that most of the organic compounds were circularity compounds. The carbon deposition can decrease the bio-oil conversion, and it was easier to form at the temperature of 750 °C.

  15. Effects of pyrolysis temperature on the physicochemical properties of empty fruit bunch and rice husk biochars.

    PubMed

    Claoston, N; Samsuri, A W; Ahmad Husni, M H; Mohd Amran, M S

    2014-04-01

    Biochar has received great attention recently due to its potential to improve soil fertility and immobilize contaminants as well as serving as a way of carbon sequestration and therefore a possible carbon sink. In this work, a series of biochars were produced from empty fruit bunch (EFB) and rice husk (RH) by slow pyrolysis at different temperatures (350, 500, and 650°C) and their physicochemical properties were analysed. The results indicate that porosity, ash content, electrical conductivity (EC), and pH value of both EFB and RH biochars were increased with temperature; however, yield, cation exchange capacity (CEC), and H, C, and N content were decreased with increasing pyrolysis temperature. The Fourier transform IR spectra were similar for both RH and EFB biochars but the functional groups were more distinct in the EFB biochar spectra. There were reductions in the amount of functional groups as pyrolysis temperature increased especially for the EFB biochar. However, total acidity of the functional groups increased with pyrolysis temperature for both biochars.

  16. Impact Resistance Behaviour of Light Weight Rice Husk Concrete with Bamboo Reinforcement

    NASA Astrophysics Data System (ADS)

    Che Muda, Zakaria; Beddu, Salmia; Syamsir, Agusril; Sigar Ating, Joshua; Liyana Mohd Kamal, Nur; Nasharuddin Mustapha, Kamal; Thiruchelvam, Sivadass; Usman, Fathoni; Ashraful Alam, Md; Birima, Ahmed H.; Zaroog, O. S.

    2016-03-01

    This paper investigate the performance of lightweight rice husk concrete (LWRHC) with varied bamboo reinforcement content for the concrete slab of 300mm × 300mm size reinforced with varied slab thickness subjected to low impact projectile test. A self-fabricated drop-weight impact test rig with a steel ball weight of 1.236 kg drop at 0.65 m height has been used in this research work. The main variables for the study is to find the relationship of the impact resistance against the amount of bamboo reinforcement and slab thickness. A linear relationship has been established between first and ultimate crack resistance against bamboo diameters and slab thickness by the experiment. The linear relationship has also been established between the service (first) crack and ultimate crack resistance against the bamboo reinforcement diameter and slab thickness. 5% RH content exhibit better first and ultimate crack resistance up to 1.80 times and up to 1.72 times respectively against 10% RH content.

  17. Biosorption of reactive dye using acid-treated rice husk: factorial design analysis.

    PubMed

    Ponnusami, V; Krithika, V; Madhuram, R; Srivastava, S N

    2007-04-02

    A factorial experimental design technique was used to investigate the biosorption of reactive red RGB (lambda(max)=521 nm) from water solution on rice husk treated with nitric acid. Biosorption is favored because of abundance of biomass, low cost, reduced sludge compared to conventional treatment techniques and better decontamination efficiency from highly diluted solutions. Factorial design of experiments is employed to study the effect of four factors pH (2 and 7), temperature (20 and 40), adsorbent dosage (5 and 50mg/L) and initial concentration of the dye (50 and 250 mg/L) at two levels low and high. The efficiency of color removal was determined after 60 min of treatment. Main effects and interaction effects of the four factors were analyzed using statistical techniques. A regression model was suggested and it was found to fit the experimental data very well. The results were analyzed statistically using the Student's t-test, analysis of variance, F-test and lack of fit to define most important process variables affecting the percentage dye removal. The most significant variable was thus found to be pH.

  18. Biosorption mechanism of nine different heavy metals onto biomatrix from rice husk.

    PubMed

    Krishnani, Kishore K; Meng, Xiaoguang; Christodoulatos, C; Boddu, Veera M

    2008-05-30

    A biomatrix was prepared from rice husk, a lignocellulosic waste from agro-industry, for the removal of several heavy metals as a function of pH and metal concentrations in single and mixed solutions. The biomatrix was characterized using scanning electron microscope and Fourier transform infrared spectroscopy, which indicated the presence of several functional groups for binding metal ions. Different experimental approaches were applied to show mechanistic aspects, especially the role of calcium and magnesium present in the biomatrix in ion exchange mechanism. The ultimate maximum adsorption capacity obtained from the Langmuir isotherm increases in the order (mmol/g): Ni (0.094), Zn (0.124), Cd (0.149), Mn (0.151), Co (0.162), Cu (0.172), Hg (0.18) and Pb (0.28). The sorption of Cr(III) onto biomatrix at pH 2 was 1.0 mmol/g. Speciation of chromium, cadmium and mercury loaded on the biomatrix was determined by X-ray photoelectron spectroscopy. The biomatrix has adsorption capacity comparable or greater to other reported sorbents.

  19. Chemical and Nanomechanical Analysis of Rice Husk Modified by ATRP-Grafted Oligomer

    PubMed Central

    Morsi, Samir M.; Pakzad, Anahita; Amin, Amal; Yassar, Reza S.; Heiden, Patricia A.

    2013-01-01

    Rice husk (RH), an abundant agricultural residue, was reacted with 2-bromoisobutyryl bromide, to convert it to a heterogeneous polyfunctional macroinitiator for Atom Transfer Radical Polymerization (ATRP). The number of active sites placed on the RH surface was small, but they were ATRP active. Non-polar methyl methacrylate (MMA) and polar acrylonitrile (AN) were polymerized from the RH, and a sequential monomer addition was used to prepare an amphiphilic PMMA-b-PAN copolymer on RH surface. FTIR qualitatively confirmed the grafting. Gravimetric and XPS analysis of the different RH surface compositions indicated thin layers of oligomeric PMMA, PAN, and PMMA-b-PAN. The modified surfaces were mapped by nanomechanical AFM to measure surface roughness, and adhesion and moduli using the Derjaguin-Muller-Toropov model. RH grafted with MMA possessed a roughness value of 7.92, and a hard and weakly adhering surface (13.1 GPa and 16.7 nN respectively) while RH grafted with AN yielded a roughness value of 29 with hardness and adhesion values of 4.0 GPa and 23.5 nN. The PMMA-b-PAN modification afforded a surface with a roughness value of 51.5 nm, with hardness and adhesion values of 3.0 GPa and .75.3 nN. PMID:21565356

  20. Synthesis of adsorbent with zeolite structure from red mud and rice husk ash and its properties

    NASA Astrophysics Data System (ADS)

    Quyen, Dinh Thi Ngoc; Loc, Luu Cam; Ha, Huynh Ky Phuong; Nga, Dang Thi Hang; Tri, Nguyen; Van, Nguyen Thi Thuy

    2017-09-01

    There are many researches in the modification of red mud as adsorbent for treatment of wastewater or waste gases. Yet, most of them have to face up with a thorny problem caused by remaining alkali in red mud. In this study, the material with zeolite structure was synthesized by fusion method using red mud with the remaining alkali and rice husk ash as raw materials. It comprised alkaline fusion followed by hydrothermal treatment with step - change of synthesis temperature. The synthesized materials were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), BET and CO2 adsorption capacity. The influences on the quality of these materialswere investigated under various calcination temperatures, calcination times and the ratios of raw materials (based on SiO2/Al2O3 ratio). The optimum reaction parameters were determined. The results depicted that the sample treated at 600 °C for 2 hours with the ratio of SiO2/Al2O3 of 1.8 had the best adsorption capacity and total specific surface area compared with the others.

  1. Strength and Durability Performance of Alkali-Activated Rice Husk Ash Geopolymer Mortar

    PubMed Central

    Kim, Yun Yong; Lee, Byung-Jae; Saraswathy, Velu

    2014-01-01

    This paper describes the experimental investigation carried out to develop the geopolymer concrete based on alkali-activated rice husk ash (RHA) by sodium hydroxide with sodium silicate. Effect on method of curing and concentration of NaOH on compressive strength as well as the optimum mix proportion of geopolymer mortar was investigated. It is possible to achieve compressive strengths of 31 N/mm2 and 45 N/mm2, respectively for the 10 M alkali-activated geopolymer mortar after 7 and 28 days of casting when cured for 24 hours at 60°C. Results indicated that the increase in curing period and concentration of alkali activator increased the compressive strength. Durability studies were carried out in acid and sulfate media such as H2SO4, HCl, Na2SO4, and MgSO4 environments and found that geopolymer concrete showed very less weight loss when compared to steam-cured mortar specimens. In addition, fluorescent optical microscopy and X-ray diffraction (XRD) studies have shown the formation of new peaks and enhanced the polymerization reaction which is responsible for strength development and hence RHA has great potential as a substitute for ordinary Portland cement concrete. PMID:25506063

  2. Fixed bed column study for Cd(II) removal from wastewater using treated rice husk.

    PubMed

    Kumar, Upendra; Bandyopadhyay, Manas

    2006-02-28

    A fixed bed of sodium carbonate treated rice husk was used for the removal of Cd(II) from water environment. The material as adopted was found to be an efficient media for the removal of Cd(II) in continuous mode using fixed bed column. The column having a diameter of 2 cm, with different bed depths such as 10, 20 and 30 cm could treat 2.96, 5.70 and 8.55 l of Cd(II) bearing wastewater with Cd(II) concentration 10 mg/l and flow rate 9.5 ml/min. Different column design parameters like depth of exchange zone, adsorption rate, adsorption capacity, etc. was calculated. Effect of flow rate and initial concentration was studied. Theoretical breakthrough curve was drawn from the batch isotherm data and it was compared with experimental breakthrough curve. An amount of 0.01 mol/l HCl solution was used for desorption of adsorption column. Column regeneration and reuse studies were conducted for two cycles of adsorption-desorption.

  3. The Effect of Various Acids on Properties of Microcrystalline Cellulose (MCC) Extracted from Rice Husk (RH)

    NASA Astrophysics Data System (ADS)

    Nur Hanani, A. S.; Zuliahani, A.; Nawawi, W. I.; Razif, N.; Rozyanty, A. R.

    2017-05-01

    Microcrystalline cellulose (MCC) was successfully extracted from rice husk (RH) via acid hydrolysis process using nitric acid (HNO3) in comparison with sulphuric acid (H2SO4) and hydrochloric acid (HCl). MCC-RH extracted using HNO3 produced the highest percentage yield at 83.5% as compared to H2SO4 and HCl at 80.6% and 81.8% respectively. Analysis of Fourier Transform Infrared (FTIR) spectroscopy affirmed the successive elimination of non-cellulosic material from RH cellulose resulting highly purified MCC-RH. X-ray Diffraction (XRD) analysis showed MCC-RH treated with HCl gives the highest crystallinity index value of 54.2% while HNO3 and H2SO4 produced comparable results of 52.4% and 49.7% respectively. The results indicate successive extraction of MCC-RH using HNO3 that has great potential to replace strong acid such as H2SO4 and HCl in acid hydrolysis.

  4. Bioregeneration of activated carbon and activated rice husk loaded with phenolic compounds: Kinetic modeling.

    PubMed

    Ng, S L; Seng, C E; Lim, P E

    2010-01-01

    A kinetic model consisting of first-order desorption and biodegradation processes was developed to describe the bioregeneration of phenol- and p-nitrophenol-loaded powdered activated carbon (PAC) and pyrolyzed rice husk (PRH), respectively. Different dosages of PAC and PRH were loaded with phenol or p-nitrophenol by contacting with the respective phenolic compound at various concentrations. The kinetic model was used to fit the phenol or p-nitrophenol concentration data in the bulk solution during the bioregeneration process to determine the rate constants of desorption, k(d), and biodegradation, k. The results showed that the kinetic model fitted relatively well (R(2)>0.9) to the experimental data for the phenol- and p-nitrophenol-loaded PAC as well as p-nitrophenol-loaded PRH. Comparison of the values of k(d) and k shows that k is much greater than k(d). This indicates clearly that the desorption process is the rate-determining step in bioregeneration and k(d) can be used to characterize the rate of bioregeneration. The trend of the variation of the k(d) values with the dosages of PAC or PRH used suggests that higher rate of bioregeneration can be achieved under non-excess adsorbent dosage condition.

  5. Removal of levofloxacin from aqueous solution using rice-husk and wood-chip biochars.

    PubMed

    Yi, Shengze; Gao, Bin; Sun, Yuanyuan; Wu, Jichun; Shi, Xiaoqing; Wu, Benjun; Hu, Xin

    2016-05-01

    The potential for rice husk (RH) and wood chip (WC) biochars to remove levofloxacin (LEV) from aqueous solution was evaluated. The physical and chemical properties of the biochars were characterized using various tools and techniques. Furthermore, batch sorption experiments were conducted to determine the sorption ability of the biochars to LEV. The pseudo-second order kinetic model described the sorption kinetic data better than the pseudo-first order kinetic model and the Elovich equation because the process involved both surface adsorption and pore diffusion. For the isotherms, the Langmuir equation fitted the data better than the Freundlich equation. The maximum Langmuir sorption capacities of the biochars to LEV ranged from 1.49 to 7.72 mg g(-1). Thermodynamic parameters obtained from the experiments showed that the adsorption of LEV onto the WC biochar was spontaneous and exothermic, while its adsorption onto the RH biochar was spontaneous and endothermic under tested conditions. A mixture of 0.025 M phosphate buffer (80%, pH 3.0) and acetonitrile (20%) effectively desorbed the LEV from the biochars with a recovery rate up to 80%. Findings from this work indicate that biochars can be used as an alternative adsorbent to effectively remove emerging contaminants including LEV from aqueous solutions.

  6. Investigation into the morphology, composition, structure and dry tribological behavior of rice husk ceramic particles

    NASA Astrophysics Data System (ADS)

    Hu, Enzhu; Hu, Kunhong; Xu, Zeyin; Hu, Xianguo; Dearn, Karl David; Xu, Yong; Xu, Yufu; Xu, Le

    2016-03-01

    To expand the application of rice husk (RH) resource, this study developed carbon-based RH ceramic (RHC) particles using a common high-temperature carbonization method. The morphology, composition, and structure of the RHC particles were characterized with a series of modern analysis technologies and were then compared with those of the initial RH powder and carbonized RH (CRH) particles. The dry tribological behavior of RHC particle adobes (RHAs) was also investigated. Results showed the sheet-shaped morphology of the RHC particles. The graphitization degree of the RHC particles was lower than that of the CRH particles possibly because the phenolic resin (PR) filled the micro-pores of the RH particles, thereby prompting the formation of amorphous carbon in the RHC particles as a result of high-temperature carbonization. The appearance of a hydroxy function group (sbnd OH) on the surface of the RHC particles was ascribed to the decomposition of PR at 900 °C. The friction coefficients and mass loss rates of the RHAs almost increased with the rise in load and velocity. In addition, the friction coefficients of the RHAs decreased at high load (5 N) and velocity (0.261 m/s) conditions. Such outcome indicated that the variation of contact area between steel ball and RHA at high load and velocity conditions resulted in the abrasive wear or catastrophic wear.

  7. Arsenic and fluoride removal by potato peel and rice husk (PPRH) ash in aqueous environments.

    PubMed

    Bibi, Sadia; Farooqi, Abida; Yasmeen, Azra; Kamran, Muhammad Aqeel; Niazi, Nabeel Khan

    2017-04-25

    Finding appropriate adsorbent may improve the quality of drinking water in those regions where arsenic (As) and fluoride (F(-)) are present in geological formations. In this study, we evaluated the efficiency of potato peel and rice husk ash (PPRH-ash) derived adsorbent for the removal of arsenic and fluoride from contaminated water. Evaluation was done in batch adsorption experiments and the effect of pH, initial adsorbate concentration, contact time and adsorbent dose were studied. The characterization of adsorbents were done using scanning electron micropcope (SEM) and Fourier transform infrared (FTIR) spectroscopy. Both the Langmuir and Freundlich isotherm models fitted well for F(-) and As sorption process. The maximum adsorption capacity of adsorbent for As and F(-) were 2.17 μg g(-1) and 2.91 mg g(-1) respectively. The optimum As and F(-) removal was observed between pH 7 and 9. The sorption process was well explained with pseudo-second order kinetic model. The As adsorption was not decreased in the presence of carbonate and sulfate. Results from this study demonstrated potential utility of this agricultural biowaste which could be developed into a viable filtration technology for As and F(-) removal in As- and F-contaminated water streams.

  8. Characteristics and mechanisms of nickel adsorption on biochars produced from wheat straw pellets and rice husk.

    PubMed

    Shen, Zhengtao; Zhang, Yunhui; McMillan, Oliver; Jin, Fei; Al-Tabbaa, Abir

    2017-05-01

    The adsorption characteristics and mechanisms of Ni(2+) on four-standard biochars produced from wheat straw pellets (WSP550, WSP700) and rice husk (RH550, RH700) at 550 and 700 °C, respectively, were investigated. The kinetic results show that the adsorption of Ni(2+) on the biochars reached an equilibrium within 5 min. The increase of the solid to liquid ratio resulted in an increase of Ni(2+) removal percentage but a decrease of the adsorbed amount of Ni(2+) per weight unit of biochar. The Ni(2+) removal percentage increased with the increasing of initial solution pH values at the range of 2-4, was relatively constant at the pH range of 4-8, and significantly increased to ≥98% at pH 9 and stayed constantly at the pH range of 9-10. The calculated maximum adsorption capacities of Ni(2+) for the biochars follow the order of WSP700 > WSP550 > RH700 > RH550. Both cation exchange capacity and pH of biochar can be a good indicator of the maximum adsorption capacity for Ni(2+) showing a positively linear and exponential relationship, respectively. This study also suggests that a carefully controlled standardised production procedure can make it reliable to compare the adsorption capacities between different biochars and investigate the mechanisms involved.

  9. Preparation of carbon black from rice husk by hydrolysis, carbonization and pyrolysis.

    PubMed

    Wang, Lili; Wang, Xiaofeng; Zou, Bo; Ma, Xiaoyu; Qu, Yuning; Rong, Chunguang; Li, Ying; Su, Ying; Wang, Zichen

    2011-09-01

    Carbon black is a form of amorphous carbon that is produced by incomplete combustion of petroleum- or some plant-derived materials and has a number of industrial uses. A process consisting of hydrolysis, carbonization and pyrolysis of rice husk was developed. Under optimal hydrolysis conditions (72 wt.% sulfuric acid, 50°C, 10 min), a hydrolysis ratio of 52.72% was achieved. After carbonization of the hydrolysis solution by water bath, the solid carbon was further pyrolyzed. As the pyrolysis temperature was increased from 400 to 800°C, the carbon content increased from 83.41% to 94.66%, the number of O-H, C-H, CO, and CC surface functional groups decreased, and based on Brunauer-Emmett-Teller (BET) results, the specific surface area and pore volume of carbon black increased from 389 to 1,034 m(2)/g and from 0.258 to 0.487 cm(3)/g, respectively. X-ray diffraction pattern (XRD) and Raman spectroscopy analyses of samples pyrolyzed at 400-800°C showed a localized graphitic structure. It is possible that the hydrolysis/carbonization/pyrolysis process developed in this study could also be applicable to the preparation of carbon black from other types of biomass.

  10. Rice husk ash as an effective adsorbent: evaluation of adsorptive characteristics for Indigo Carmine dye.

    PubMed

    Lakshmi, Uma R; Srivastava, Vimal Chandra; Mall, Indra Deo; Lataye, Dilip H

    2009-02-01

    Present study explored the adsorptive characteristics of Indigo Carmine (IC) dye from aqueous solution onto rice husk ash (RHA). Batch experiments were carried out to determine the influence of parameters like initial pH (pH(0)), contact time (t), adsorbent dose (m) and initial concentration (C(0)) on the removal of IC. The optimum conditions were found to be: pH(0)=5.4, t=8h and m=10.0 g/l. The pseudo-second-order kinetic model represented the adsorption kinetics of IC on to RHA. Equilibrium isotherms were analyzed by Freundlich, Langmuir, Temkin and Redlich-Peterson models using a non-linear regression technique. Adsorption of IC on RHA was favorably influenced by an increase in the temperature of the operation. The positive values of the change in entropy (DeltaS(0)) and heat of adsorption (DeltaH(0)); and the negative value of change in Gibbs free energy (DeltaG(0)) indicate feasible and spontaneous adsorption of IC on to RHA.

  11. Removal of elemental mercury by iodine-modified rice husk ash sorbents.

    PubMed

    Zhao, Pengfei; Guo, Xin; Zheng, Chuguang

    2010-01-01

    Iodine-modified calcium-based rice husk ash sorbents (I2/CaO/RHA) were synthesized and characterized by X-ray diffraction, X-ray fluorescence, and N2 isotherm adsorption/desorption. Adsorption experiments of vapor-phase elemental mercury (Hg0) were performed in a laboratory-scale fixed-bed reactor. I2/CaO/RHA performances on Hg0 adsorption were compared with those of modified Ca-based fly ash sorbents (I2/CaO/FA) and modified fly ash sorbents (I2/FA). Effects of oxidant loading, supports, pore size distribution, iodine impregnation modes, and temperature were investigated as well to understand the mechanism in capturing Hg0. The modified sorbents exhibited reasonable efficiency for Hg0 removal under simulated flue gas. The surface area, pore size distribution, and iodine impregnation modes of the sorbents did not produce a strong effect on Hg0 capture efficiency, while fair correlation was observed between Hg0 uptake capacity and iodine concentration. Therefore, the content of I2 impregnated on the sorbents was identified as the most important factor influencing the capacity of these sorbents for Hg0 uptake. Increasing temperature in the range of 80-140 degrees C caused a rise in Hg0 removal. A reaction mechanism that may explain the experimental results was presumed based on the characterizations and adsorption study.

  12. Adsorption of perfluorinated compounds on aminated rice husk prepared by atom transfer radical polymerization.

    PubMed

    Deng, Shubo; Niu, Li; Bei, Yue; Wang, Bin; Huang, Jun; Yu, Gang

    2013-04-01

    Adsorption is considered as an effective method to remove perfluorinated compounds (PFCs) from aqueous solution. In this study, an aminated rice husk (RH) adsorbent was successfully prepared through surface-initiated atom transfer radical polymerization (ATRP) and subsequent amination reaction, and it was used to remove perfluorooctanoate (PFOA), perfluorobutanoic acid (PFBA) and perfluorooctane sulfonate (PFOS) from aqueous solution. Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) analysis verified the presence of grafted polymer brushes and amine groups on the RH surface. The zero point of zeta potential of aminated RH was 8.5, which facilitated the sorption of anionic PFCs on the positively charged adsorbent at pH below 8.5. The sorption equilibria of PFOA, PFBA and PFOS were achieved within 5 h, 3 h and 9 h, respectively, faster than the reported porous adsorbents. Sorption isotherms showed that the adsorption capacities of PFOA, PFBA and PFOS on the aminated RH at pH 5.0 were 2.49, 1.70 and 2.65 mmol g(-1), respectively. Sorption behavior and X-ray photoelectron spectroscopy (XPS) analysis confirmed that the electrostatic and hydrophobic interactions were involved in the sorption process, and the micelles and hemi-micelles of PFOA and PFOS may form on the adsorbent surface.

  13. Biosorption of model pollutants in liquid phase on raw and modified rice husks

    NASA Astrophysics Data System (ADS)

    Toniazzo, L.; Fierro, V.; Braghiroli, F.; Amaral, G.; Celzard, A.

    2013-03-01

    We studied the application of rice husk (RH) as a biosorbent and we demonstrated that it can be employed for the treatment of dyeing wastewater streams. RH was obtained from Nile Delta (Egypt) and it was used as received, or after a chemical treatment using HNO3 or NaOH, or after conversion into activated carbon (RH-AC) using H3PO4 as activating agent. A commercial activated carbon GAC 830 provided by NORIT was also tested for comparison purposes. These materials were evaluated by adsorption of methylene blue (MB) with an initial concentration of 20 ppm in an aqueous solution at 30°C. The results showed that alkali-treated and RH-AC were the best sorbents. They got a nearly complete MB removal from water and they had better performance than GAC 830. Therefore, the use of RH for pollutant removal makes this method an environment-friendly option and an economically feasible alternative to treat industrial effluents.

  14. Synthesis of silicon carbide from rice husk in a dc arc plasma reactor

    SciTech Connect

    Nayak, B.B.; Mohanty, B.C.; Singh, S.K.

    1996-05-01

    SiC particles have been synthesized in the {alpha}-phase from a mixture of boiler-burnt rice husk and graphite powder in a dc extended arc plasma reactor on a 200--250 g scale. A SiC yield as high as 72% was achieved at a 3.03:1 carbon-to-silica ratio. 21R polytypism, which is rare to grow, was observed in the SiC. About 90% of the SiC particles produced were found to lie under 163 {micro}m, 50% under 90 {micro}m, and 10% under 28 {micro}m size. Very fine particles under 10 {micro}m size occurred to the extent of 3%. XRD and SEM characterizations were carried out to study the phase and morphology of the particles. Heterogeneous gas-phase reactions seem to be responsible for intermediate-size SiC particle growth in the multitemperature zone dc extended arc plasma reactor.

  15. Kinetic study of brilliant green adsorption from aqueous solution onto white rice husk ash.

    PubMed

    Tavlieva, Mariana P; Genieva, Svetlana D; Georgieva, Velyana G; Vlaev, Lyubomir T

    2013-11-01

    The present research was focused on the study of adsorption kinetics of brilliant green (BG) onto white rice husk ash from aqueous solutions. The research was performed in the temperature interval 290-320 K in 10° steps and in the concentration range of 3-100 mg L(-1). Batch studies were conducted in order to determine the optimal adsorbent dose, and the time required to reach the adsorption equilibrium at each temperature. The effect of the initial concentration of brilliant green was studied (pH not adjusted), as well as the effect of temperature. The maximum adsorption capacity of the WRHA for BG at 320 K was determined to be 85.56 mg g(-1). The adsorption kinetic data were analyzed employing several kinetic models: pseudo-first-order equation, pseudo-second-order equation, Elovichequation, Banghman's equation, Diffusion-chemisorption model, and Boyd kinetic expression. It was established that the adsorption process obeyed the pseudo-second-order kinetic model. Based on the rate constants obtained by this kinetic model using Arrhenius and Eyring equations, the activation parameters were determined, namely the activation energy (50.04 kJ mol(-1)), the change of entropy (-318.31 J mol(-1) K(-1)), enthalpy (-47.50 kJ mol(-1)), and Gibbs free energy (range 44.81-54.36 kJ mol(-1)) for the formation of activated complex from the reagents.

  16. Simultaneous removal of pesticides from water by rice husk ash: batch and column studies.

    PubMed

    Saha, Ajoy; Gajbhiye, V T; Gupta, Suman; Kumar, Rajesh; Ghosh, Rakesh Kumar

    2014-11-01

    The present study evaluated rice husk ash (RHA) as an adsorbent for simultaneous removal of a mixture of seven different pesticides (alachlor, metolachlor, chlorpyriphos, fipronil, α-endosulfan, β-endosulfan, and p,p'-DDT) and two metabolites (p,p'-DDE and endosulfan sulfate) from water. The adsorbent RHA was prepared in the laboratory and characterized by techniques such as X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, and scanning electron microscopy/energy-dispersive X-ray spectrometry. Adsorption kinetics were well described by the pseudo-second-order kinetic model. The Freundlich isotherm model fitted the equilibrium data better than the Langmuir model, and the maximum sorption capacity varied from 0.078 to 0.166 mg/g. The column elution studies showed that 10 L of mixed pesticide-contaminated water (0.05 mg/L) can be treated with only 10 g of RHA at a removal efficiency of 90%. The results implied that RHA can be used as a low-cost, easily available, and efficient adsorbent for the simultaneous removal of pesticides from contaminated water.

  17. Optimization of synthesis and characterization of nanosilica produced from rice husk (a common waste material)

    NASA Astrophysics Data System (ADS)

    Rafiee, Ezzat; Shahebrahimi, Shabnam; Feyzi, Mostafa; Shaterzadeh, Mahdi

    2012-10-01

    Rice husk (RH), an inexpensive waste material, was used to produce nanosilica. Acid treatment of RH followed by thermal combustion under controlled conditions gave 22.50% ash of which 90.469% was silica. Various chemical treatments in varied conditions for controlled combustion were investigated in order to produce highly purified nanosilica. The structural properties (such as X-ray diffraction, Brunauer-Emmett-Teller, Fourier transform infrared spectroscopy, and transmission electron microscopy) of the silica were studied. The method was optimized, and the chemical composition of the product was determined by X-ray fluorescence and carbon, hydrogen, and nitrogen analysis. Lime reactivity of the ashes was determined. At optimized conditions, a nanosized, highly purified silica (98.8 mass percentage) was produced with a high surface area, high reactivity, and 99.9% amorphous in form. Strength and number of acidic sites were measured by potentiometric titration. This nanosilica showed strong and a large number of acidic sites in comparison with commercial silica, making it as a good support for catalysts. This economic technology, as applied to waste material, also provides many benefits to the local agro-industry.

  18. Rice Husk Ash-Derived Silica Nanofluids: Synthesis and Stability Study

    NASA Astrophysics Data System (ADS)

    Zhang, Zhiliang; He, Wenxiu; Zheng, Jianzhong; Wang, Guangquan; Ji, Jianbing

    2016-11-01

    Nanofluids, colloidal suspensions consisting of base fluids and nanoparticles, are a new generation of engineering working fluids. Nanofluids have shown great potential in heat/mass transfer applications. However, their practical applications are limited by the high production cost and low stability. In this study, a low-cost agricultural waste, rice husk ash (RHA), was used as a silicon source to the synthesis of silica nanofluids. First, silica nanoparticles with an average size of 47 nm were synthesized. Next, by dispersing the silica nanoparticles in water with ultrasonic vibration, silica nanofluids were formed. The results indicated that the dispersibility and stability of nanofluids were highly dependent on sonication time and power, dispersant types and concentrations, as well as pH; an optimal experiment condition could result in the highest stability of silica nanofluid. After 7 days storage, the nanofluid showed no sedimentation, unchanged particle size, and zeta potential. The results of this study demonstrated that there is a great potential for the use of RHA as a low-cost renewable resource for the production of stable silica nanofluids.

  19. Strength and durability performance of alkali-activated rice husk ash geopolymer mortar.

    PubMed

    Kim, Yun Yong; Lee, Byung-Jae; Saraswathy, Velu; Kwon, Seung-Jun

    2014-01-01

    This paper describes the experimental investigation carried out to develop the geopolymer concrete based on alkali-activated rice husk ash (RHA) by sodium hydroxide with sodium silicate. Effect on method of curing and concentration of NaOH on compressive strength as well as the optimum mix proportion of geopolymer mortar was investigated. It is possible to achieve compressive strengths of 31 N/mm(2) and 45 N/mm(2), respectively for the 10 M alkali-activated geopolymer mortar after 7 and 28 days of casting when cured for 24 hours at 60°C. Results indicated that the increase in curing period and concentration of alkali activator increased the compressive strength. Durability studies were carried out in acid and sulfate media such as H2SO4, HCl, Na2SO4, and MgSO4 environments and found that geopolymer concrete showed very less weight loss when compared to steam-cured mortar specimens. In addition, fluorescent optical microscopy and X-ray diffraction (XRD) studies have shown the formation of new peaks and enhanced the polymerization reaction which is responsible for strength development and hence RHA has great potential as a substitute for ordinary Portland cement concrete.

  20. Microwave-induced transformation of rice husks to SiC

    NASA Astrophysics Data System (ADS)

    Qadri, S. B.; Imam, M. A.; Fliflet, A. W.; Rath, B. B.; Goswami, R.; Caldwell, J. D.

    2012-04-01

    Samples of rice husks were transformed to β (3C)-SiC by microwave processing in controlled conditions of temperature and vacuum. This simple and fast way of producing powdered samples of silicon carbide is technologically important if this material is to be used for electronics, sensors, biotechnology, and other applications. Using x-ray diffraction it was found that the microwave processed sample at 1900 °C consists of β (3C)-SiC phase. Raman scattering measurements confirmed the formation of β (3C)-SiC phase. Transmission electron microscopy revealed the presence of stacking faults along the [111] direction. The presence of 6H/4H stacking faults in 3C phase is explained in terms of their total energies. The presence of these stacking faults with a ˜1 eV band offset between the host 3C and hexagonal stacking faults implies that these stacking faults provide a conduction barrier, and the interfaces between the stacking faults and host lattice act as a heterojunction that may provide potential utility for various optoelectronic applications.

  1. Evaluation of sulfate resistance of cement mortars containing black rice husk ash.

    PubMed

    Chatveera, B; Lertwattanaruk, P

    2009-03-01

    In this paper, black rice husk ashes (BRHAs), which are agrowastes from an electricity generating power plant and a rice mill, were ground and used as a partial cement replacement. The durability of mortars under sulfate attack including expansion and compressive strength loss were investigated. For parametric study, BRHA were used as a Portland cement Type 1 replacement at the levels of 0%, 10%, 30%, and 50% by weight of binder. The water-to-binder ratios were 0.55 and 0.65. For the durability of mortar exposed to sulfate attack, 5% sodium sulfate (Na2SO4) and magnesium sulfate (MgSO4) solutions were used. As a result, when increasing the percentage replacement of BRHA, the expansion and compressive strength loss of mortar decreased. At the replacement levels of 30% and 50% of BRHA, the expansion of the mortars was less than those mixed with sulfate-resistant cement. However, the expansion of the mortars exposed to Na2SO4 was more than those exposed to MgSO4. Increasing the replacement level of BRHA tends to reduce the compressive strength loss of mortars exposed to Na2SO4 attack. In contrary, under MgSO4 attack, when increasing the replacement level of BRHA, the compressive strength loss increases from 0% to 50% in comparison to Portland cement mortar. Results show that ground BRHA can be applied as a pozzolanic material to concrete and also improve resistance to sodium sulfate attack, but it can impair resistance to magnesium sulfate attack.

  2. Adsorption characteristics of malachite green on activated carbon derived from rice husks produced by chemical-thermal process.

    PubMed

    Rahman, I A; Saad, B; Shaidan, S; Sya Rizal, E S

    2005-09-01

    Phosphoric acid (H(3)PO(4)) and sodium hydroxide (NaOH) treated rice husks, followed by carbonization in a flowing nitrogen were used to study the adsorption of malachite green (MG) in aqueous solution. The effect of adsorption on contact time, concentration of MG and adsorbent dosage of the samples treated or carbonized at different temperatures were investigated. The results reveal that the optimum carbonization temperature is 500 degrees C in order to obtain adsorption capacity that is comparable to the commercial activated carbon for the husks treated by H(3)PO(4). It is interesting to note that MG adsorbed preferably on carbon-rich than on silica rich-sites. It is found that the behaviour of H(3)PO(4) treated absorbent followed both the Langmuir and Freundlich models while NaOH treated best fitted to only the Langmuir model.

  3. The influence of activating agents on the performance of rice husk-based carbon for sodium lauryl sulfate and chrome (Cr) metal adsorptions

    NASA Astrophysics Data System (ADS)

    Arneli; Safitri, Z. F.; Pangestika, A. W.; Fauziah, F.; Wahyuningrum, V. N.; Astuti, Y.

    2017-02-01

    This research aims to study the influence of activating agents to produce rice husk based-carbon with high adsorption capacity and efficiency for either hazardous organic molecules or heavy metals which are unfriendly for the environment. Firstly, rice husk was burned by pyrolysis at different temperatures to produce rice husk-based carbon. To improve its ability as an adsorbent, carbon was treated with activating agents, namely, H3PO4 and KOH at room and high temperature (420 °C). The performance of carbon was then tested by contacting it with surfactant (SLS). Finally, the surfactant-modified active carbon was applied for chrome metal removal. The result shows that activation of carbon using phosphate acid (H3PO4) was more effective than potassium hydroxide (KOH) conducted at high temperature to adsorb sodium lauryl sulfate (SLS) and chrome metal with the adsorption capacity 1.50 mgg-1 and 0.375 mgg-1, respectively.

  4. Effects of acidified aqueous glycerol and glycerol carbonate pretreatment of rice husk on the enzymatic digestibility, structural characteristics, and bioethanol production.

    PubMed

    Ebrahimi, Majid; Villaflores, Oliver B; Ordono, Emma E; Caparanga, Alvin R

    2017-03-01

    Rice husk as an abundant biomass was used in this study, and it contained 30.1% glucan and 13.5% xylan, 22.4% lignin. The pretreated rice husk with glycerol carbonate and acidified aqueous glycerol (10% water) at 90°C and 130°C for 60min had the maximum yield of glucan digestibility which was 78.2% and 69.7% respectively, using cellulase for 72h. The simultaneous saccharification and fermentation was conducted anaerobically at 37°C with Saccharomyces cerevisiae, 5% w/v glucan and 10FPU/g glucan of cellulase. 11.58 and 8.84g/L was the highest ethanol concentration after 3days of incubation form pretreated rice husk with glycerol carbonate and acidified aqueous glycerol respectively. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Production of activated carbon from bagasse and rice husk by a single-stage chemical activation method at low retention times.

    PubMed

    Kalderis, Dimitrios; Bethanis, Sophia; Paraskeva, Panagiota; Diamadopoulos, Evan

    2008-10-01

    The production of activated carbon from bagasse and rice husk by a single-stage chemical activation method in short retention times (30-60min) was examined in this study. The raw materials were subjected to a chemical pretreatment and were fed to the reactor in the form of a paste (75% moisture). Chemicals examined were ZnCl2, NaOH and H3PO4, for temperatures of 600, 700 and 800 degrees C. Of the three chemical reagents under evaluation only ZnCl2 produced activated carbons with high surface areas. BET surface areas for rice husk were up to 750m2/g for 1:1 ZnCl2:rice husk ratio. BET surface areas for bagasse were up to 674m2/g for 0.75:1 ZnCl2:bagasse ratio. Results were compared to regular two-stage physical activation methods.

  6. Sorption potential of rice husk for the removal of 2,4-dichlorophenol from aqueous solutions: kinetic and thermodynamic investigations.

    PubMed

    Akhtar, Mubeena; Bhanger, M I; Iqbal, Shahid; Hasany, S Moosa

    2006-01-16

    The sorption potential of chemically and thermally treated rice husk (RHT) for the removal of 2,4-dichlorophenol (DCP) from aqueous solutions has been investigated. Sorption of DCP by rice husk was observed over a wide pH range of 1-10. The effect of contact time between liquid and solid phases, sorbent dose, pH, concentration of sorbate and temperature on the sorption of DCP onto rice husk has been studied. The pore area and average pore diameter of RHT by BET method are calculated to be 17+/-0.6 m2g-1 and 51.3+/-1.5 nm, respectively. Maximum sorption (98+/-1.2%) was achieved for RHT from 6.1x10(-5) moldm(-3) of sorbate solution using 0.1g of rice husk for 10 min agitation time at pH 6 and 303K, which is comparable to activated carbon commercial (ACC) 96.6+/-1.2%, but significantly higher than chemically treated rice husk (RHCT) 65+/-1.6% and rice husk untreated (RHUT) 41+/-2.3%. The sorption data obtained at optimized conditions was subjected to Freundlich, Langmuir and Dubinin-Radushkevich (D-R) isotherms. Sorption intensity 1/n (0.31+/-0.01) and sorption capacity multilayer C(m) (12.0+/-1.6 mmolg(-1)) have been evaluated using Freundlich sorption isotherm, whereas the values of sorption capacity monolayer Q (0.96+/-0.03 mmolg(-1)) and binding energy, b, (4.5+/-1.0)x10(4)dm(3)mol(-1) have been estimated by Langmuir isotherm. The Langmuir constant, b, was also used to calculate the dimensionless factor, R(L), in the concentration range (0.6-6.1)x10(-4) moldm(-3), suggesting greater sorption at low concentration. D-R sorption isotherm was employed to calculate sorption capacity X(m) (2.5+/-0.07 mmolg(-1)) and sorption energy E (14.7+/-0.13 kJmol(-1)). Lagergren and Morris-Weber equations were employed to study kinetics of sorption process using 0.2g of RHT, 25 cm(3) of 0.61x10(-4)moldm(-3) sorbate concentration at pH 6, giving values of first-order rate constant, k, and rate constant of intraparticle transport, R(id), (0.48+/-0.04 min(-1) and 6.8+/-0.8 nmolg(-1

  7. Photoreduction of mercury metal (Hg) using catalyst of oxalic acid from cellulose of rice husks (Oryza sativa L.)

    SciTech Connect

    Sumiardi, Ade; Novi, Cory; Sukaesih, Esih; Humaedi, Aji

    2016-04-19

    Photoreduction of mercury metal using catalyst of oxalic acid from cellulose of rice husks (Oryza sativa L.) is one of methods to reduce toxicity properties of the mercury metal in the society. The purpose of this research is to enhance photoreduction of mercury metal using catalyst of oxalic acid from cellulose of rice husks (Oryza sativa L.) at various concentrations. Photoreduction process is carried out in a closed reactor equipped with UV light and magnetic stirrer. Analysis of the influence of oxalic acid is determined by adding 25 mL of Hg (II) 5 ppm without oxalic acid, 25 mL of Hg (II) 5 ppm + 25 mL of oxalic acid 3 ppm, 25 mL of Hg (II) 5 ppm + 25 mL of oxalic acid 6 ppm, 25 mL of Hg (II) 5 ppm + 25 mL of oxalic acid 9 ppm, 25 mL of Hg (II) 5 ppm + 25 mL of oxalic acid 12 ppm and 25 mL of Hg (II) 5 ppm + 25 mL of oxalic acid 15 ppm. All treatments are followed by centrifugation for 15 minutes, then the concentration of Hg residual in the solution is measured by mercury analyzer. The research results showed that addition of oxalic acid concentration from the cellulose of rice husks (Oryza sativa L.) can enhance photoreduction of mercury metal. Optimum concentration reduction of mercury metal with addition of oxalic acid is obtained as many as 9-12 ppm. It can reduce the concentration of mercury metal (II) by 68.8% to 88.6%.

  8. Synthesis of Na-A and/or Na-X zeolite/porous carbon composites from carbonized rice husk

    SciTech Connect

    Katsuki, Hiroaki; Komarneni, Sridhar

    2009-07-15

    Na-A and/or Na-X zeolite/porous carbon composites were prepared under hydrothermal conditions by NaOH dissolution of silica first from carbonized rice husk followed by addition of NaAlO{sub 2} and in situ crystallization of zeolites i.e., using a two-step process. When a one-step process was used, both Na-A and Na-X zeolites crystallized on the surface of carbon. Na-A or Na-X zeolite crystals were prepared on the porous carbonized rice husk at 90 deg. C for 2-6 h by changing the SiO{sub 2}/Al{sub 2}O{sub 3}, H{sub 2}O/Na{sub 2}O and Na{sub 2}O/SiO{sub 2} molar ratios of precursors in the two-step process. The surface area and NH{sub 4}{sup +}-cation exchange capacity (CEC) of Na-A zeolite/porous carbon were found to be 171 m{sup 2}/g and 506 meq/100 g, respectively, while those of Na-X zeolite/porous carbon composites were 676 m{sup 2}/g and 317 meq/100 g, respectively. Na-A and Na-X zeolites are well-known microporous and hydrophilic materials while carbonized rice husk was found to be mesoporous (pores of {approx}3.9 nm) and hydrophobic. These hybrid microporous-mesoporous and hydrophilic-hydrophobic composites are expected to be useful for decontamination of metal cations as well as organic contaminants simultaneously. - Graphical Abstract: Novel Na-X zeolite/porous carbon composite.

  9. Rice Husk Silica-Derived Nanomaterials for Battery Applications: A Literature Review.

    PubMed

    Shen, Yafei

    2017-02-08

    Silica-rich rice husk (RH) is an abundant and sustainable agricultural waste. The recovery of value-added products from RH or its ash to explore an economic way for the valorization of agricultural wastes has attracted wide attention. For instance, RH can be converted to biofuels and biochars simultaneously via thermochemical processes. In general, the applications of RH biochars include soil remediation, pollutant removal, silicon battery materials, and so forth. This review concludes recent progress in the synthesis of RH-derived silicon materials for lithium-ion battery (LIB) applications. Silica nanomaterials produced from RH are initially discussed. RH amorphous silica can also be fabricated to crystal silicon used for battery materials via widely used magnesiothermic reduction. However, the RH-derived Si nanoparticles suffer from a low Coulombic efficiency in the initial charge/discharge and limited cycle life as anode materials due to high surface reactions and low thermodynamic stability. The synthesis of Si materials with nano/microhierarchical structure would be an ideal way to improve their electrochemical performances. Embedding nano-Si into 3D conductive matrix is an effective way to improve the structural stability. Among the Si/carbon composite materials, carbon nanotubdes (CNTs) are a promising matrix due to the wired morphology, high electronic conductivity, and robust structure. Additionally, CNTs can easily form 3D cross-linked conducting networks, ensuring effective electron transportation among active particles. Si nanomaterials with microhierarchical structures in which CNTs are tightly intertwined between the RH-derived Si nanoparticles have been proven to be ideal LIB anode materials.

  10. Key factor in rice husk Ash/CaO sorbent for high flue gas desulfurization activity.

    PubMed

    Dahlan, Irvan; Lee, Keat Teong; Kamaruddin, Azlina Harun; Mohamed, Abdul Rahman

    2006-10-01

    Siliceous materials such as rice husk ash (RHA) have potential to be utilized as high performance sorbents for the flue gas desulfurization process in small-scale industrial boilers. This study presents findings on identifying the key factorfor high desulfurization activity in sorbents prepared from RHA. Initially, a systematic approach using central composite rotatable design was used to develop a mathematical model that correlates the sorbent preparation variables to the desulfurization activity of the sorbent. The sorbent preparation variables studied are hydration period, x1 (6-16 h), amount of RHA, x2 (5-15 g), amount of CaO, x3 (2-6 g), amount of water, x4 (90-110 mL), and hydration temperature, x5 (150-250 degrees C). The mathematical model developed was subjected to statistical tests and the model is adequate for predicting the SO2 desulfurization activity of the sorbent within the range of the sorbent preparation variables studied. Based on the model, the amount of RHA, amount of CaO, and hydration period used in the preparation step significantly influenced the desulfurization activity of the sorbent. The ratio of RHA and CaO used in the preparation mixture was also a significant factor that influenced the desulfurization activity of the sorbent. A RHA to CaO ratio of 2.5 leads to the formation of specific reactive species in the sorbent that are believed to be the key factor responsible for high desulfurization activity in the sorbent. Other physical properties of the sorbent such as pore size distribution and surface morphology were found to have insignificant influence on the desulfurization activity of the sorbent.

  11. Biochar characteristics produced from rice husks and their sorption properties for the acetanilide herbicide metolachlor.

    PubMed

    Wei, Lan; Huang, Yufen; Li, Yanliang; Huang, Lianxi; Mar, Nyo Nyo; Huang, Qing; Liu, Zhongzhen

    2017-02-01

    Rice husk biochar (RHBC) was prepared for use as adsorbents for the herbicide metolachlor. The characteristics and sorption properties of metolachlor adsorbed by the RHBC prepared at different pyrolysis temperatures were determined by analysis of physico-chemical characteristics, Fourier transform infrared spectroscopy (FTIR), Boehm titration, scanning electron microscopy (SEM), and thermodynamics and kinetics adsorption. With increasing pyrolysis temperature, the RHBC surface area greatly increased (from 2.57 to 53.08 m(2) g(-1)). RHBC produced at the highest temperature (750 °C) had the greatest surface area; SEM also showed the formation of a porous surface on RH-750 biochar. The sorption capacity of RHBC also increased significantly with increasing pyrolysis temperature and was characterized by the Freundlich constant K f for the adsorption capacity increasing from 125.17-269.46 (pyrolysis at 300 °C) to 339.94-765.24 (pyrolysis at 750 °C). The results indicated that the surface area and pore diameter of RHBC produced with high pyrolysis temperature (i.e., 750 °C) had the greatest impact on the adsorption of metolachlor. The FTIR, Boehm titration, and SEM analysis showed that the greatest number of surface groups were on RHBC produced at the lowest temperature (300 °C). The biochars produced at different pyrolysis temperatures had different mechanisms of adsorbing metolachlor, which exhibited a transition from hydrogen bonds dominant at low pyrolytic temperature to pore-filling dominant at higher pyrolytic temperature.

  12. A study on modification of nanoporous rice husk silica for hydrophobic nano filter.

    PubMed

    Kim, Hee Jin; So, Soo Jeong; Han, Chong Soo

    2010-05-01

    Nanoporous rice husk silica (RHS) was modified with alkylsilylation reagents, hexamethyldisilazane, diethoxydiphenylsilane, dichlorodimethylsilane and n-octodecyltrimethoxysilane. The silica samples were characterized with Raman spectrometer, thermal gravimetric analyzer, scanning electron microscope, nitrogen adsorption measurement and solid state nuclear magnetic resonance spectrometer. Raman spectra of the modified silica showed growth of the peaks of C-H stretching and CH3 bending at approximateluy 3000 cm(-1) and approximately 1500 cm(-1), respectively. Weight losses of 3 approximately 5% were observed in thermo gravimetric profiles of the modified silica. The microscopic shape of RHS, approximately 20 nm primary particles and their aggregates was almost not changed by the modification but there were colligations of the silica particles in the sample treated with dichlorodimethylsilane or diethoxydiphenylsilane. BET adsorption experiment showed the modification significantly decreased the mean pore size of the silica from approximately 5 nm to approximately 4 nm as well as the pore volume from 0.5 cm3/g to 0.4 cm3/g except the case of treatment with n-octodecyltrimethoxysilane. 29Si Solid NMR Spectra of the silica samples showed that there were decrease in the relative intensities of Q2 and Q3 peaks and large increments in Q4 after the modification except for the case of bulky n-octodecyltrimethoxysilane. From the results, it was concluded that the alkylsilylation reagents reacted with hydroxyl groups on the silica particles as well as in the nano pores while the size of the reagent molecule affected its diffusion and reaction with the hydroxyl groups in the pores.

  13. Synthesis of NaX zeolite using silica from rice husk ash

    SciTech Connect

    Dalal, A.K.; Gokhale, K.V.G.K.; Rao, M.S.

    1985-09-01

    Sodium X zeolite has been synthesized by using rice husk ash as a source of silica for the first time. The synthesis has been carried out for temperatures ranging from 95 to 120 /sup 0/ C and duration of synthesis from 1 to 24 h with SiO/sub 2//AI/sub 2/O/sub 3/, Na/sub 2/O/AI/sub 2/O/sub 3/, and H/sub 2/O/AI/sub 2/O/sub 3/ molar ratios ranging from 2.0 to 7.0, 2.4 to 10.0, and 96.0 to 890.0, respectively. The roles of temperature, duration of synthesis, and composition of initial mix in the formation of NaX zeolite and the stability of NaX zeolite were studied. In the present study, it has been observed that the NaX zeolite can be synthesized from an initial mix with SiO/sub 2//AI/sub 2/O/sub 3/ and Na/sub 2/O/SiO/sub 2/ molar ratios varying from 3 to 5.5 and 0.75 to 2.22, respectively, and having H/sub 2/O/Na/sub 2/O molar ratios from 30 to 60 at 100 /sup 0/ C with reaction times of 6 to 8 h. The product at each stage has been characterized by X-ray diffraction analysis. Studies on the crystallization kinetics and morphological investigations for the formation of NaX zeolite were also carried out.

  14. Key factor in rice husk ash/CaO sorbent for high flue gas desulfurization activity

    SciTech Connect

    Irvan Dahlan; Keat Teong Lee; Azlina Harun Kamaruddin; Abdul Rahman Mohamed

    2006-10-01

    Siliceous materials such as rice husk ash (RHA) have potential to be utilized as high performance sorbents for the flue gas desulfurization process in small-scale industrial boilers. This study presents findings on identifying the key factor for high desulfurization activity in sorbents prepared from RHA. Initially, a systematic approach using central composite rotatable design was used to develop a mathematical model that correlates the sorbent preparation variables to the desulfurization activity of the sorbent. The sorbent preparation variables studied are hydration period, x{sub 1} (6-16 h), amount of RHA, x{sub 2} (5-15 g), amount of CaO, x{sub 3} (2-6 g), amount of water, x{sub 4} (90-110 mL), and hydration temperature, x{sub 5} (150-250{sup o}C). The mathematical model developed was subjected to statistical tests and the model is adequate for predicting the SO{sub 2} desulfurization activity of the sorbent within the range of the sorbent preparation variables studied. Based on the model, the amount of RHA, amount of CaO, and hydration period used in the preparation step significantly influenced the desulfurization activity of the sorbent. The ratio of RHA and CaO used in the preparation mixture was also a significant factor that influenced the desulfurization activity of the sorbent. A RHA to CaO ratio of 2.5 leads to the formation of specific reactive species in the sorbent that are believed to be the key factor responsible for high desulfurization activity in the sorbent. Other physical properties of the sorbent such as pore size distribution and surface morphology were found to have insignificant influence on the desulfurization activity of the sorbent. 31 refs., 5 figs., 3 tabs.

  15. Bacillus oryzaecorticis sp. nov., a moderately halophilic bacterium isolated from rice husks.

    PubMed

    Hong, Sung Wook; Kwon, Soon-Wo; Kim, Soo-Jin; Kim, Song Yi; Kim, Jong Jin; Lee, Jong Sung; Oh, Mi-Hwa; Kim, Ae-Jung; Chung, Kun Sub

    2014-08-01

    A Gram-stain-positive, aerobic, endospore-forming, moderately halophilic rod, designated strain R1(T), was isolated from rice husks and subjected to a taxonomic study using a polyphasic approach. Strain R1(T) produced spherical or ellipsoidal endospores at a subterminal position in swollen sporangia, and was catalase- and oxidase-positive. The isolate grew optimally at 37 °C and pH 6.0-7.0, and could grow in the presence of up to 9% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain R1(T) belongs to the genus Bacillus. The closest relatives of strain R1(T) were Bacillus subtilis subsp. subtilis NCIB 3610(T), Bacillus aquimaris TF-12(T), and Bacillus marisflavi TF-11(T), with 16S rRNA gene sequence similarities of 96.0%, 98.4%, and 98.7%, respectively. DNA-DNA relatedness values between the isolate and the reference strains were ≤42±3%. The predominant menaquinones were MK-5 (50%) and MK-7 (50%). The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, and phosphatidylethanolamine. The major cellular fatty acids were iso-C(15 : 0) (48.6%) and anteiso-C(15 : 0) (20.6%), and the cell-wall diamino acid was meso-diaminopimelic acid. On the basis of 16S rRNA gene sequence analyses and chemotaxonomic and phenotypic characteristics, it is concluded that strain R1(T) represents a novel species of the genus Bacillus, for which we propose the name Bacillus oryzaecorticis sp. nov. The type strain is R1(T) ( = KACC 17217(T) = KCCM 90231(T) = JCM 19602(T)). © 2014 IUMS.

  16. Determination of RH-5849 and indoxacarb in rice straw, rice husk, brown rice and soil using liquid chromatography-tandem triple quadrupole mass spectrometry following extraction with QuEChERS method.

    PubMed

    Li, Zhurui; Zhao, Xiaozhen; Chen, Jiaojiao; Wu, Yue; Zhang, Jing; Zhang, Kankan; Hu, Deyu

    2016-10-01

    A fast and simple analytical method was developed for the simultaneous determination of RH-5849 and indoxacarb in soil, rice straw, rice husk and brown rice. QuEChERS (quick, easy, cheap, effective, rugged and safe) method was used for extraction, and liquid chromatography with tandem triple quadrupole mass spectrometry was used for quantification. The matrix-matched calibration plots were linear in the range between 25 and 5000 μg/L for soil, rice straw, rice husk and brown rice samples. All determination coefficients (R(2) ) were ≥0.9962. The limits of detection and quantification were 1.5 and 5 μg/kg, respectively. Recoveries at three fortification levels ranged between 79.5 and 97.9% with relative standard deviations <11%. The developed method was validated and applied for the analysis of dissipation study samples. For field experiments, the half-lives of RH-5849 and indoxacarb in rice straw were 11.93 and 5.83 days, respectively. The method was demonstrated to be reliable for the routine monitoring of RH-5849 and indoxacarb in rice samples. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  17. Preparation and characterization of electron-beam treated HDPE composites reinforced with rice husk ash and Brazilian clay

    NASA Astrophysics Data System (ADS)

    Ortiz, A. V.; Teixeira, J. G.; Gomes, M. G.; Oliveira, R. R.; Díaz, F. R. V.; Moura, E. A. B.

    2014-08-01

    This work evaluates the morphology, mechanical and thermo-mechanical properties of high density polyethylene (HDPE) composites. HDPE reinforced with rice husk ashes (80:20 wt%), HDPE reinforced with clay (97:3 wt%) and HDPE reinforced with both rice husk ashes and clay(77:20:3 wt%) were obtained. The Brazilian bentonite chocolate clay was used in this study. This Brazilian smectitic clay is commonly used to produce nanocomposites. The composites were produced by melting extrusion process and then irradiation was carried out in a 1.5 MeV electron-beam accelerator (room temperature, presence of air). Comparisons using the irradiated and non-irradiated neat polymer, and the irradiated and non-irradiated composites were made. The materials obtained were submitted to tensile, flexural and impact tests. Additionally HDT, SEM and XRD analyses were carried out along with the sol-gel analysis which aimed to assess the cross-linking degree of the irradiated materials. Results showed great improvement in most HDPE properties and a high cross-linking degree of 85% as a result of electron-beam irradiation of the material.

  18. Evaluation of slow pyrolyzed wood and rice husks biochar for adsorption of ammonium nitrogen from piggery manure anaerobic digestate slurry.

    PubMed

    Kizito, Simon; Wu, Shubiao; Kipkemoi Kirui, W; Lei, Ming; Lu, Qimin; Bah, Hamidou; Dong, Renjie

    2015-02-01

    Due to its high adsorption capacity, the use of biochar to capture excess nutrients from wastewater has become a central focus in environmental remediation studies. In this study, its potential use in adsorption and removal of ammonium in piggery manure anaerobic digestate slurry was investigated. The adsorbed amount of NH4(+)-N (mg·g(-1)) and removal percentage as a function of adsorbent mass in solution, adsorbent particle size, NH4(+)-N concentration in the effluent, contact time, pH and temperature were quantified in batch equilibrium and kinetics experiments. The maximum NH4(+)-N adsorption from slurry at 1400 mgN·L(-1) was 44.64 ± 0.602 mg·g(-1) and 39.8 ± 0.54 mg·g(-1) for wood and rice husk biochar, respectively. For both biochars, adsorption increased with increase in contact time, temperature, pH and NH4(+)-N concentration but it decreased with increase in biochar particle size. Furthermore, the sorption process was endothermic and followed Langmuir (R(2)=0.995 and 0.998) and Pseudo-second order kinetic models (R(2)=0.998 and 0.999). Based on the removal amounts, we concluded that rice husk and wood biochar have potential to adsorb NH4(+)-N from piggery manure anaerobic digestate slurry, and thus can be used as nutrient filters prior to discharge into water streams. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Furfural production from rice husk using sulfuric acid and a solid acid catalyst through a two-stage process.

    PubMed

    Ren, Suxia; Xu, Haiyan; Zhu, Jinling; Li, Shunqing; He, Xiaofeng; Lei, Tingzhou

    2012-10-01

    This study aimed to optimize the conditions for furfural production from rice husk via a two-stage process: acid hydrolysis followed by dehydration using an orthogonal test design and response surface methodology, respectively. Orthogonal test design was utilized in the hydrolysis step; optimum conditions were as follows: 2.5% sulfuric acid (mass fraction), 110°C reaction temperature, sulfuric acid to rice husk (L/S) ratio of 8 (g/mL), and a reaction time of 3h. According to the Box-Behnken design, the temperature, amount of catalyst, extractant volume, and reaction time were chosen as four important factors with three levels for the dehydration step. Conditions were further optimized by response surface analysis. The results showed that the optimal conditions were 177°C, 120 mL extractant volume, 2.1g of catalyst, and a reaction time of 4.8h. Under the optimal conditions, the furfural yield reached 8.9%, which is consistent with the estimated value, 8.97%. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Superabsorbent nanocomposite synthesis of cellulose from rice husk grafted poly(acrylate acid-co-acrylamide)/bentonite

    NASA Astrophysics Data System (ADS)

    Helmiyati; Abbas, G. H.; Kurniawan, S.

    2017-04-01

    Superabsorbent nanocomposite synthesis of cellulose rice husk as the backbone with free radical polymerization method in copolymerization grafted with acrylic acid and acrylamide monomer. The cellulose was isolated from rice husk with mixture of toluene and ethanol and then hemicellulose and lignin were removed by using potassium hydroxide 4% and hydrogen peroxide 2%. The obtained cellulose rendement was 37.85%. The functional group of lignin analyzed by FTIR spectra was disappeared at wavenumber 1724 cm-1. Crystal size of the obtained isolated cellulose analyzed by XRD diffraction pattern was 34.6 nm, indicated the nanocrystal structure. Copolymerization was performed at temperature of 70°C with flow nitrogen gas. Initiator and crosslinking agent used were potassium persulfate and N‧N-methylene-bis-acrylamide. The swelling capacity of water and urea showed the results was quite satisfactory, the maximum swelling capacity in urea and water were 611.700 g/g and 451.303 g/g, respectively, and can be applied in agriculture to absorb water and urea fertilizer.

  1. Fabrication of Activated Rice Husk Charcoal by Slip Casting as a Hybrid Material for Water Filter Aid

    NASA Astrophysics Data System (ADS)

    Tuaprakone, T.; Wongphaet, N.; Wasanapiarnpong, T.

    2011-04-01

    Activated charcoal has been widely used as an odor absorbent in household and water purification industry. Filtration equipment for drinking water generally consists of four parts, which are microporous membrane (porous alumina ceramic or diatomite, or porous polymer), odor absorbent (activated carbon), hard water treatment (ion exchange resin), and UV irradiation. Ceramic filter aid is usually prepared by slip casting of alumina or diatomite. The membrane offers high flux, high porosity and maximum pore size does not exceed 0.3 μm. This study investigated the fabrication of hybrid activated charcoal tube for water filtration and odor absorption by slip casting. The suitable rice husk charcoal and water ratio was 48 to 52 wt% by weight with 1.5wt% (by dry basis) of CMC binder. The green rice husk charcoal bodies were dried and fired between 700-900 °C in reduction atmosphere. The resulting prepared slip in high speed porcelain pot for 60 min and sintered at 700 °C for 1 h showed the highest specific surface area as 174.95 m2/g. The characterizations of microstructure and pore size distribution as a function of particle size were investigated.

  2. Reinforcement of natural rubber hybrid composites based on marble sludge/Silica and marble sludge/rice husk derived silica

    PubMed Central

    Ahmed, Khalil; Nizami, Shaikh Sirajuddin; Riza, Nudrat Zahid

    2013-01-01

    A research has been carried out to develop natural rubber (NR) hybrid composites reinforced with marble sludge (MS)/Silica and MS/rice husk derived silica (RHS). The primary aim of this development is to scrutinize the cure characteristics, mechanical and swelling properties of such hybrid composite. The use of both industrial and agricultural waste such as marble sludge and rice husk derived silica has the primary advantage of being eco-friendly, low cost and easily available as compared to other expensive fillers. The results from this study showed that the performance of NR hybrid composites with MS/Silica and MS/RHS as fillers is extremely better in mechanical and swelling properties as compared with the case where MS used as single filler. The study suggests that the use of recently developed silica and marble sludge as industrial and agricultural waste is accomplished to provide a probable cost effective, industrially prospective, and attractive replacement to the in general purpose used fillers like china clay, calcium carbonate, and talc. PMID:25685484

  3. Reinforcement of natural rubber hybrid composites based on marble sludge/Silica and marble sludge/rice husk derived silica.

    PubMed

    Ahmed, Khalil; Nizami, Shaikh Sirajuddin; Riza, Nudrat Zahid

    2014-03-01

    A research has been carried out to develop natural rubber (NR) hybrid composites reinforced with marble sludge (MS)/Silica and MS/rice husk derived silica (RHS). The primary aim of this development is to scrutinize the cure characteristics, mechanical and swelling properties of such hybrid composite. The use of both industrial and agricultural waste such as marble sludge and rice husk derived silica has the primary advantage of being eco-friendly, low cost and easily available as compared to other expensive fillers. The results from this study showed that the performance of NR hybrid composites with MS/Silica and MS/RHS as fillers is extremely better in mechanical and swelling properties as compared with the case where MS used as single filler. The study suggests that the use of recently developed silica and marble sludge as industrial and agricultural waste is accomplished to provide a probable cost effective, industrially prospective, and attractive replacement to the in general purpose used fillers like china clay, calcium carbonate, and talc.

  4. Synthesis of nanosized ZSM-5 zeolite using extracted silica from rice husk without adding any alumina source

    NASA Astrophysics Data System (ADS)

    Sari, Zahra Ghasemi Laleh Vajheh; Younesi, Habibollah; Kazemian, Hossein

    2015-08-01

    The synthesis of analcime and nanosized ZSM-5 zeolites was carried out by a hydrothermal method with silica extracted from rice husk, available as an inexpensive local biowaste, and without the use of an extra alumina source. Amorphous silica (with 88 wt% of SiO2) was extracted from rice husk ash by a suitable alkali solution. The effects of crystallization temperature, time and SiO2/Al2O3 ratio of the initial system on the properties of final products were investigated. For the characterization of the synthesized product, X-ray diffraction, scanning electron microscope, energy dispersive X-ray techniques, Fourier transform infrared and Brunauer-Emmett-Teller method were applied. Crystallinity percentages of analcime and nanosized ZSM-5 were 95.86 and 89.56, respectively, with specific surface area of 353.5 m2 g-1 for ZSM-5. The experimental results revealed that the synthesis of analcime and nanosized ZSM-5 zeolites was more practical with using silica extracted from inexpensive raw materials, while the whole crystallization process was accomplished without adding any alumina source during.

  5. Characterization of Sodium Carbonate (Na2CO3) Treated Rice Husk Activated Carbon and Adsorption of Lead from Car Battery Wastewater

    NASA Astrophysics Data System (ADS)

    Hanum, F.; Bani, O.; Izdiharo, A. M.

    2017-03-01

    The use of rice husk as adsorbent would not only reduce its disposal problems, but would also produce value-added products, such as activated carbon derived from rice husk. This study aimed to determine the optimum carbonization temperature for activated carbon production from rice husk and its adsorption performance on Pb in car battery wastewater. In this study, activated carbon was produced by carbonizing rice husk 400-600 °C for 90-150 minutes followed by chemical activation using 5% Na2CO3 and sieving to 100 meshes. Lead adsorption was measured using atomic absorption spectroscopy (AAS). Results suggested that highest carbon yield of 47.75% was obtained for carbonization at 500 °C for 150 minutes. At that condition, produced activated carbon contained 3.35% moisture, 30.86% ash, 18.04% volatile matter. The adsorption capacity was found to be 0.6007 mg lead/g adsorbent with % adsorpsi 58.08%

  6. Efficiency of a cleanup technology to remove mercury from natural waters by means of rice husk biowaste: ecotoxicological and chemical approach.

    PubMed

    Rocha, Luciana S; Lopes, I; Lopes, Cláudia B; Henriques, Bruno; Soares, Amadeu M V M; Duarte, Armando C; Pereira, Eduarda

    2014-01-01

    In the present work, the efficiency of rice husk to remove Hg(II) from river waters spiked with realistic environmental concentrations of this metal (μg L(-1) range) was evaluated. The residual levels of Hg(II) obtained after the remediation process were compared with the guideline values for effluents discharges and water for human consumption, and the ecotoxicological effects using organisms of different trophic levels were assessed. The rice husk sorbent proved to be useful in decreasing Hg(II) contamination in river waters, by reducing the levels of Hg(II) to values of ca. 8.0 and 34 μg L(-1), for an Hg(II) initial concentration of 50 and 500 μg L(-1), respectively. The remediation process with rice husk biowaste was extremely efficient in river waters spiked with lower levels of Hg(II), being able to eliminate the toxicity to the exposed organisms algae Pseudokirchneriella subcapitata and rotifer Brachionus calyciflorus and ensure the total survival of Daphnia magna species. For concentrations of Hg(II) tenfold higher (500 μg L(-1)), the remediation process was not adequate in the detoxification process, still, the rice husk material was able to reduce considerably the toxicity to the bacteria Vibrio fischeri, algae P. subcapitata and rotifer B. calyciflorus, whose responses where fully inhibited during its exposure to the non-remediated river water. The use of a battery of bioassays with organisms from different trophic levels and whose sensitivity revealed to be different and dependent on the levels of Hg(II) contamination proved to be much more accurate in predicting the ecotoxicological hazard assessment of the detoxification process by means of rice husk biowaste.

  7. An economically viable method for the removal of selected divalent metal ions from aqueous solutions using activated rice husk.

    PubMed

    Akhtar, Mubeena; Iqbal, Shahid; Kausar, Abida; Bhanger, M I; Shaheen, Muhammad Ashraf

    2010-01-01

    Biosorption of divalent metal ions, i.e. Pb(II), Cd(II), Zn(II) and Cu(II) onto rice husk activated (RHA) is investigated over pH range (1-10) via batch adsorption technique. The chemical and thermal activation of rice husk with 0.1M HNO(3) and 1M K(2)CO(3) at 473 K enhanced the removal efficiency of RHA (35+/-2.1-99+/-0.5%, 33+/-1.2-97+/-0.6%, 32+/-1.3-96+/-0.8% and 28+/-1.8-95+/-0.9% before and after treatment, respectively). The surface area analysis of RHA by BET (Brunauer, Emmett and Teller) nitrogen adsorption method provided pore area and average pore diameter to be 542+/-2.3m(2)g(-1) and 1076+/-5.6 nm respectively. SEM and FTIR analyses of RHA were carried out to determine the surface morphology and functional groups involved in metal binding mechanism, respectively. The adsorption equilibrium was well described by Freundlich, Langmuir and Dubinin-Radushkevish (D-R) isotherm models by employing (4.8-48, 8.9-89, 15.3-153 and 15.7-157)x10(-5)M solution concentrations of sorbates, respectively, at equilibrium time of 20 min at pH 6 and onto 0.2g of sorbent. The kinetics of mass transfer and intra-particle diffusion for metal ions sorption onto RHA were studied with Lagergren and Morris-Weber kinetic models. The numerical values of thermodynamic parameters indicated the exothermic nature, spontaneity and feasibility of the sorption process. The desorption study of metal components from RHA surface was carried out with 0.1M HCl. The sorption mechanism developed illustrates the strong interactions of sorbates with the active sites of the sorbent coupled with efficient and environmentally clean exploitation of rice waste product.

  8. Agricultural waste as household fuel: techno-economic assessment of a new rice-husk cookstove for developing countries.

    PubMed

    Vitali, Francesco; Parmigiani, Simone; Vaccari, Mentore; Collivignarelli, Carlo

    2013-12-01

    In many rural contexts of the developing world, agricultural residues and the organic fraction of waste are often burned in open-air to clear the lands or just to dispose them. This is a common practice which generates uncontrolled emissions, while wasting a potential energy resource. This is the case of rice husk in the Logone Valley (Chad/Cameroon). In such a context household energy supply is a further critical issue. Modern liquid fuel use is limited and traditional solid fuels (mainly wood) are used for daily cooking in rudimentary devices like 3-stone fires, resulting in low efficiency fuel use, huge health impacts, increasing exploitation stress for the local natural resources. Rice husk may be an alternative fuel to wood for household energy supply. In order to recover such a biomass, the authors are testing a proper stove with an original design. Its lay-out (featuring a metal-net basket to contain the fuel and a chimney to force a natural air draft) allows a mix of combustion/gasification of the biomass occurring in a completely burning fire, appropriate for cooking tasks. According to results obtained with rigorous test protocols (Water Boiling Test), different lay-outs have been designed to improve the performance of the stove. Technical and economic issues have been addressed in the development of such a model; building materials have been chosen in order to guarantee a cost as low as possible, using locally available items. The feasibility of the introduction of the stove in the studied context was assessed through an economic model that keeps into account not only the technology and fuel costs, but also the energy performance. According to the model, the threshold for the trade-off of the stove is the use of rice husk to cover 10-15% of the household energy needs both with traditional fireplaces or with improved efficiency cookstoves. The use of the technology proposed in combination with improved woodstove would provide householders with an

  9. Preparation of SiO2 nanowires from rice husks by hydrothermal method and the RNA purification performance

    NASA Astrophysics Data System (ADS)

    Huang, Meiyan; Cao, Jianping; Meng, Xing; Liu, Yangsi; Ke, Wei; Wang, Jialiang; Sun, Ling

    2016-10-01

    In this study, SiO2 nanowires were prepared by using rice husks as silicon source via a hydrothermal method. The microstructure, thermal stability and morphology of SiO2 nanowires were characterized by X-ray diffraction, infrared spectroscopy, thermal gravimetric analysis and scanning electron microscope. SiO2 nanowires with a diameter of 30-100 nm were obtained and the formation mechanism of SiO2 nanowires during the hydrothermal reaction was proposed. The SiO2 nanowires were introduced into membrane spin columns to isolate RNA and the values of A260/280 and A260/230 were 2.0-2.1 and 1.8-2.0, respectively, which shows the SiO2 nanowires were effective for RNA purification.

  10. Pyrolysis of Sawdust, Rice Husk and Sugarcane Bagasse: Kinetic Modeling and Estimation of Kinetic Parameters using Different Optimization Tools

    NASA Astrophysics Data System (ADS)

    Khonde, Ruta Dhanram; Chaurasia, Ashish Subhash

    2015-04-01

    The present study provides the kinetic model to describe the pyrolysis of sawdust, rice-husk and sugarcane bagasse as biomass. The kinetic scheme used for modelling of primary pyrolysis consisting of the two parallel reactions giving gaseous volatiles and solid char. Estimation of kinetic parameters for pyrolysis process has been carried out for temperature range of 773-1,173 K. As there are serious issues regarding non-convergence of some of the methods or solutions converging to local-optima, the proposed kinetic model is optimized to predict the best values of kinetic parameters for the system using three approaches—Two-dimensional surface fitting non-linear regression technique, MS-Excel Solver Tool and COMSOL software. The model predictions are in agreement with experimental data over a wide range of pyrolysis conditions. The estimated value of kinetic parameters are compared with earlier researchers and found to be matching well.

  11. Kinetics of sequential reaction of hydrolysis and sugar degradation of rice husk in ethanol production: effect of catalyst concentration.

    PubMed

    Megawati; Sediawan, Wahyudi B; Sulistyo, Hary; Hidayat, Muslikhin

    2011-01-01

    This study focuses on kinetics of rice husk hydrolysis using sulfuric acid catalyst to produce sugars. The experiments were conducted at various catalyst concentrations. It turned out that during hydrolysis, degradation of sugars was encountered. The kinetics was expressed with both homogeneous and heterogeneous models. At catalyst concentration of higher than 0.44 N, heterogeneous model works better than homogeneous model, while at the lower, both models work well. In the heterogeneous model, it is observed that the mass transfer of sulfuric acid in the particles and the hydrolysis reaction control the rate of hydrolysis. The mass transfer can be described by Fick's law with the effective diffusivity of 1.4×10(-11) cm2/s, while the hydrolysis and sugar degradation rate constants follow Arrhenius equations. In addition, it was experimentally observed that the sugars produced can be converted to ethanol by fermentation using yeast.

  12. Isolation of lignin by organosolv process from different varieties of rice husk: Understanding their physical and chemical properties.

    PubMed

    Singh, Sandip K; Dhepe, Paresh L

    2016-12-01

    The aim of this work was to study the difference in properties of lignins, those (organosolv lignins (ORGLs, 12±3% yield and 93±5% mass balance) were isolated from diverse rice husk (RH) substrates using organosolv procedure (water:ethanol, H2SO4) carried out at 180°C for 1h. To identify the possible alterations in lignin structures several bulk and molecular level advanced characterization tools were employed. Even though lignins were extracted using common isolation procedure from three varieties of similar species of RH; from XRD, GPC, and elemental analysis it was found that those have comparable properties on bulk level. But molecular level analysis conducted using UV-vis, ATR, 1D/2D HSQC NMR techniques could help disclose that isolated lignins have varying concentrations of G, H, S and T substructures. Additionally, the double bond equivalence of 4.4-4.7 reveals that few of the aromatic rings are devoid of substituent.

  13. Application of mineral bed materials during fast pyrolysis of rice husk to improve water-soluble organics production.

    PubMed

    Li, R; Zhong, Z P; Jin, B S; Zheng, A J

    2012-09-01

    Fast pyrolysis of rice husk was performed in a spout-fluid bed to produce water-soluble organics. The effects of mineral bed materials (red brick, calcite, limestone, and dolomite) on yield and quality of organics were evaluated with the help of principal component analysis (PCA). Compared to quartz sand, red brick, limestone, and dolomite increased the yield of the water-soluble organics by 6-55% and the heating value by 16-19%. The relative content of acetic acid was reduced by 23-43% with calcite, limestone and dolomite when compared with quartz sand. The results from PCA showed all minerals enhanced the ring-opening reactions of cellulose into furans and carbonyl compounds rather than into monomeric sugars. Moreover, calcite, limestone, and dolomite displayed the ability to catalyze the degradation of heavy compounds and the demethoxylation reaction of guaiacols into phenols. Minerals, especially limestone and dolomite, were beneficial to the production of water-soluble organics.

  14. Synergistic effect of rice husk addition on hydrothermal treatment of sewage sludge: fate and environmental risk of heavy metals.

    PubMed

    Shi, Wansheng; Liu, Chunguang; Shu, Youju; Feng, Chuanping; Lei, Zhongfang; Zhang, Zhenya

    2013-12-01

    Hydrothermal treatment (HTT) at 200°C was applied to immobilize heavy metals (HMs) and the effect of rice husk (RH) addition was investigated based on total HMs concentration, fractionation and leaching tests. The results indicated that a synergistic effect of RH addition and HTT could be achieved on reducing the risk of HMs from medium and low risk to no risk. Metals were redistributed and transformed from weakly bounded state to stable state during the HTT process under RH addition. Notably at a RH/sludge ratio of 1/1.75 (d.w.), all the HMs showed no eco-toxicity and no leaching toxicity, with the concentrations of leachable Cr, Ni, Cu and Cd decreased by 17%, 89%, 95% and 93%, respectively. This synergistic effect of RH addition and HTT on the risk reduction of HMs implies that HTT process with RH addition could be a promising and safe disposal technology for sewage sludge treatment in practice.

  15. Hydrogen-rich gas production via CaO sorption-enhanced steam gasification of rice husk: a modelling study.

    PubMed

    Beheshti, Sayyed Mohsen; Ghassemi, Hojat; Shahsavan-Markadeh, Rasoul; Fremaux, Sylvain

    2015-01-01

    Gasification is a thermochemical process in which solid or liquid fuels are transformed into synthesis gas through partial oxidation. In this paper, a kinetic model of rice husk gasification has been developed, which is interesting for the applications of the syngas produced. It is a zero-dimensional, steady-state model based on global reaction kinetic, empirical correlation of pyrolysis and is capable of predicting hydrogen yield in the presence of sorbent CaO. The model can also be used as a useful tool to investigate the influence of process parameters including steam/biomass ratio, CaO/fuel ratio (CaO/Fuel), and gasification temperature on hydrogen efficiency, CO2 capture ratio (CCR), and average carbonation conversion (Save). Similar to hydrogen formation, CCR also increases with increasing CaO/Fuel, but an opposite trend is exhibited in Save. Model predictions were compared with available data from the literature, which showed fairly good agreement.

  16. Pozzolanic Reactivity of Silica Fume and Ground Rice Husk Ash as Reactive Silica in a Cementitious System: A Comparative Study

    PubMed Central

    Xu, Weiting; Lo, Tommy Yiu; Wang, Weilun; Ouyang, Dong; Wang, Penggang; Xing, Feng

    2016-01-01

    This study comparably assessed the pozzolanic effect of silica fume (SF) and ground rice husk ash (RHA) as supplementary cementing materials on the properties of blended cement pastes and concretes. A commonly commercial silica fume (SF) and locally-produced rice husk ash (RHA) samples with two finenesses (one with larger size than cement and the other with smaller size than cement) were used in this study. Material properties of SF and RHA were experimentally characterized. Hydration and mechanical properties of cement pastes incorporating SF and RHA were determined by thermogravimetric analysis (TGA) and compressive strength tests, respectively. Properties of concretes regarding workability, mechanical property, durability, and microstructure were evaluated. Results showed that, although the finely ground RHA used in this study possessed lower SiO2 content and higher particle size compared to SF, it exhibited comparable pozzolanic reactivity with SF due to the nano-scale pores on its each single particle, leading to a higher specific surface area. The optimal replacement levels of SF and RHA were 10% by weight of cement in pastes and concretes. Although addition of SF and RHA led to a significant reduction in slump for the fresh mixtures, inclusion of up to 30% of SF or 15% of ground RHA did not adversely affect the strength of concretes. At the same mix, incorporation of finely-ground RHA in cement composites provided comparable mechanical properties, hydration degree, and durability with SF blended cement composites, owing to the porous structure and high specific surface area of RHA particles. Microstructure morphology analysis of concretes explored by scanning electron microscopy (SEM) further validated the strength and the durability test results. PMID:28773271

  17. Evaluation of nitric and acetic acid resistance of cement mortars containing high-volume black rice husk ash.

    PubMed

    Chatveera, B; Lertwattanaruk, P

    2014-01-15

    This paper presents the performance of cement mortar containing black rice husk ash (BRHA) under nitric and acetic acid attacks. The BRHA, collected from an electrical generating power plant that uses rice husk as fuel, was ground using a grinding machine. The compressive strength loss, weight loss, and expansion of mortars under nitric and acetic acid attack were investigated. The test results of BRHA properties in accordance with the ASTM C 618 standard found that the optimal grinding time was 4 h as this achieved a Blaine fineness of 5370 cm(2)/g. For parametric study, BRHA were used as a Portland cement Type 1 replacement at the levels of 0%, 10%, 20%, 30%, 40%, and 50% by weight of binder. The water-to-binder ratios were 0.55, 0.60, and 0.65. From test results, when the percentage replacements of BRHA in cement increased, it was observed that the strength loss and weight loss of mortars containing BRHA under acetic acid attack were higher than those of the mortars against nitric acid attack. It was found that, of the various BHRA mortars, the strength loss and weight loss due to nitric and acetic acid attacks were the lowest in the mortar with 10% BRHA replacement. For 10%, 20% and 30% BRHA replacements, the rate of expansion of the BRHA mortar decreased when compared with the control mortar. For the mortars with other percentage replacements of BRHA, the rate of expansion increased. Furthermore, the effective water-to-binder ratios of control and BRHA mortars were the primary factor for determining the durability of mortar mixed with BRHA. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Removal of Cr(VI) from aqueous solutions using pre-consumer processing agricultural waste: a case study of rice husk.

    PubMed

    Bansal, Manjeet; Garg, Umesh; Singh, Diwan; Garg, V K

    2009-02-15

    This paper reports the feasibility of using pre-consumer processing agricultural waste to remove Cr(VI) from synthetic wastewater under different experimental conditions. For this, rice husk, has been used after pre-treatments (boiling and formaldehyde treatment). Effect of various process parameters, namely, pH, adsorbent dose, initial chromium concentration and contact time has been studied in batch systems. The removal of chromium was dependent on the physico-chemical characteristics of the adsorbent, adsorbate concentration and other studied process parameters. Maximum metal removal was observed at pH 2.0. The efficiencies of boiled and formaldehyde treated rice husk for Cr(VI) removal were 71.0% and 76.5% respectively for dilute solutions at 20gl(-1) adsorbent dose. The experimental data were analyzed using Freundlich, Langmuir and Dubinin-Radushkevich (D-R) isotherm models. It was found that Freundlich and D-R models fitted well. The results revealed that the hexavalent chromium is considerably adsorbed on rice husk and it could be an economical method for the removal of hexavalent chromium from aqueous systems. FTIR and SEM were recorded, before and after adsorption, to explore number and position of the functional groups available for Cr(VI) binding on to studied adsorbents and changes in adsorbent surface morphology.

  19. Synthesis and characterisation of composite based biohydroxyapatite bovine bone mandible waste (BHAp) doped with 10 wt % amorphous SiO2 from rice husk by solid state reaction

    NASA Astrophysics Data System (ADS)

    Asmi, Dwi; Sulaiman, Ahmad; Oktavia, Irene Lucky; Badaruddin, Muhammad; Zulfia, Anne

    2016-04-01

    Effect of 10 wt% amorphous SiO2 from rice husk addition on the microstructures of biohydroxyapatite (BHAp) obtained from bovine bone was synthesized by solid state reaction. In this study, biohydroxyapatite powder was obtained from bovine bone mandible waste heat treated at 800 °C for 5 h and amorphous SiO2 powder was extracted from citric acid leaching of rice husk followed by combustion at 700°C for 5 h. The composite powder then mixed and sintered at 1200 °C for 3 h. X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy and Scanning electron microscopy (SEM) techniques are utilized to characterize the phase relations, functional group present and morphology of the sample. The study has revealed that the processing procedures played an important role in microstructural development of BHAp-10 wt% SiO2 composite. The XRD study of the raw material revealed that the primary phase material in the heat treated of bovine bone mandible waste is hydroxyapatite and in the combustion of rice husk is amorphous SiO2. However, in the composite the hydroxyapatite, β-tricalcium phosphate, and calcium phosphate silicate were observed. The FTIR result show that the hydroxyl stretching band in the composite decrease compared with those of hydroxyapatite spectra and the evolution of morphology was occurred in the composite.

  20. Rice Husk Ash to Stabilize Heavy Metals Contained in Municipal Solid Waste Incineration Fly Ash: First Results by Applying New Pre-treatment Technology

    PubMed Central

    Benassi, Laura; Franchi, Federica; Catina, Daniele; Cioffi, Flavio; Rodella, Nicola; Borgese, Laura; Pasquali, Michela; Depero, Laura E.; Bontempi, Elza

    2015-01-01

    A new technology was recently developed for municipal solid waste incineration (MSWI) fly ash stabilization, based on the employment of all waste and byproduct materials. In particular, the proposed method is based on the use of amorphous silica contained in rice husk ash (RHA), an agricultural byproduct material (COSMOS-RICE project). The obtained final inert can be applied in several applications to produce “green composites”. In this work, for the first time, a process for pre-treatment of rice husk, before its use in the stabilization of heavy metals, based on the employment of Instant Pressure Drop technology (DIC) was tested. The aim of this work is to verify the influence of the pre-treatment on the efficiency on heavy metals stabilization in the COSMOS-RICE technology. DIC technique is based on a thermomechanical effect induced by an abrupt transition from high steam pressure to a vacuum, to produce changes in the material. Two different DIC pre-treatments were selected and thermal annealing at different temperatures were performed on rice husk. The resulting RHAs were employed to obtain COSMOS-RICE samples, and the stabilization procedure was tested on the MSWI fly ash. In the frame of this work, some thermal treatments were also realized in O2-limiting conditions, to test the effect of charcoal obtained from RHA on the stabilization procedure. The results of this work show that the application of DIC technology into existing treatment cycles of some waste materials should be investigated in more details to offer the possibility to stabilize and reuse waste. PMID:28793605

  1. Chemical characterization and oxidative potential of particles emitted from open burning of cereal straws and rice husk under flaming and smoldering conditions

    NASA Astrophysics Data System (ADS)

    Fushimi, Akihiro; Saitoh, Katsumi; Hayashi, Kentaro; Ono, Keisuke; Fujitani, Yuji; Villalobos, Ana M.; Shelton, Brandon R.; Takami, Akinori; Tanabe, Kiyoshi; Schauer, James J.

    2017-08-01

    Open burning of crop residue is a major source of atmospheric fine particle emissions. We burned crop residues (rice straws, barley straws, wheat straws, and rice husks produced in Japan) in an outdoor chamber and measured particle mass, composition (elemental carbon: EC, organic carbon: OC, ions, elements, and organic species), and oxidative potential in the exhausts. The fine particulate emission factors from the literature were within the range of our values for rice straws but were 1.4-1.9 and 0.34-0.44 times higher than our measured values for barley straw and wheat straw, respectively. For rice husks and wheat straws, which typically lead to combustion conditions that are relatively mild, the EC content of the particles was less than 5%. Levoglucosan seems more suitable as a biomass burning marker than K+, since levoglucosan/OC ratios were more stable than K+/particulate mass ratios among crop species. Stigmasterol and β-sitosterol could also be used as markers of biomass burning with levoglucosan or instead of levoglucosan. Correlation analysis between chemical composition and combustion condition suggests that hot or flaming combustions enhance EC, K+, Cl- and polycyclic aromatic hydrocarbons emissions, while low-temperature or smoldering combustions enhance levoglucosan and water-soluble organic carbon emissions. Oxidative potential, measured with macrophage-based reactive oxygen species (ROS) assay and dithiothreitol (DTT) assay, of open burning fine particles per particulate mass as well as fine particulate emission factors were the highest for wheat straws and second highest for rice husks and rice straws. Oxidative potential per particulate mass was in the lower range of vehicle exhaust and atmosphere. These results suggest that the contribution of open burning is relatively small to the oxidative potential of atmospheric particles. In addition, oxidative potential (both ROS and DTT activities) correlated well with water-insoluble organic species

  2. Biosorption of Fe(II) and Mn(II) Ions from Aqueous Solution by Rice Husk Ash

    PubMed Central

    Zhao, Jiaying; Jiang, Zhao; Shan, Dexin; Lu, Yan

    2014-01-01

    Rice husk ash (RHA), an agricultural waste, was used as biosorbent for the removal of Iron(II) and Manganese(II) ions from aqueous solutions. The structural and morphological characteristics of RHA and its elemental compositions before and after adsorption of Fe(II) and Mn(II) were determined by scanning electron microscopic (SEM) and X-ray fluorescence (XRF) analyses. Batch experiments were carried out to determine the influence of initial pH, contact time, adsorbent dosage, and initial concentration on the removal of Fe(II) and Mn(II) ions. Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) models were applied to describe the biosorption isotherm of the metal ions by RHA. The correlation coefficient (R2) of Langmuir and Freundlich isotherm models equals 0.995 and 0.901 for Fe(II), 0.9862 and 0.8924 for Mn(II), respectively, so the Langmuir model fitted the equilibrium data better than the Freundlich isotherm model. The mean free energy values evaluated from the D-R model indicated that the biosorption of Fe(II) and Mn(II) onto RHA was physical in nature. Experimental data also showed that the biosorption processes of both metal ions complied with the pseudo-second-order kinetics. PMID:24982918

  3. Evolution of char structure during steam gasification of the chars produced from rapid pyrolysis of rice husk.

    PubMed

    Fu, Peng; Hu, Song; Xiang, Jun; Yi, Weiming; Bai, Xueyuan; Sun, Lushi; Su, Sheng

    2012-06-01

    The structural evolution of rice husk char particles during steam gasification was studied by ultimate analysis, inductively coupled plasma atomic emission spectroscopy, scanning electronic microscope, N(2) physisorption method and X-ray diffraction. Drastic changes in char structure occurred even when the char conversion was minimal. The C, H and O content decreased by more than 85%, 67% and 91%, respectively. The H/C atomic ratio always increased, while the O/C exhibited a "∼" shape. The maximum porosity appeared at char conversion of 48.6%. D(s) and d(ave) showed a good linear relationship. Aliphatic structures and smaller aromatic rings tended to be preferentially consumed to left the char more ordered and enriched with larger aromatic ring systems. The presence of steam favored the volatilization of Na. K, Mg and Ca showed a similar behavior and their concentrations reached maxima at 60.3%. Great loss of O-containing structures caused significant volatilization of K, Mg and Ca.

  4. Elucidation of the thermal deterioration mechanism of bio-oil pyrolyzed from rice husk using Fourier transform infrared spectroscopy.

    PubMed

    Xu, Fang; Xu, Yu; Lu, Rui; Sheng, Guo-Ping; Yu, Han-Qing

    2011-09-14

    In this study, the rationale for exploring the thermal deterioration mechanism of the bio-oil pyrolyzed from rice husk is established. This is based on identification of the unstable intermediates in the thermal deterioration process. Fourier transform infrared (FTIR) spectroscopy was used to monitor such a thermal deterioration process of bio-oil samples in thermal treatment and/or during long-term storage at ambient temperatures of 20-30 °C. Terminal olefins, as a key intermediate, so-called "signature", were identified qualitatively by using FTIR spectroscopy. A band shift observed at 880 cm(-1), which was assigned to the C-H out-of-plane deformation vibration of terminal olefins, indicates the start-up of the bio-oil thermal deterioration. A two-step pathway was proposed to describe the thermal deterioration process of bio-oil. This study suggests that the status of bio-oil could be rapidly monitored by the FTIR method.

  5. Esterification of oil adsorbed on palm decanter cake into methyl ester using sulfonated rice husk ash as heterogeneous acid catalyst

    NASA Astrophysics Data System (ADS)

    Hindryawati, Noor; Erwin, Maniam, Gaanty Pragas

    2017-02-01

    Palm Decanter cake (PDC) which is categorized as the waste from palm oil mill has been found to contain residual crude palm oil. The oil adsorbed on the PDC (PDC-oil) can be extracted and potentially used as feedstock for biodiesel production. Feedstock from waste like PDC-oil is burdened with high free fatty acids (FFAs) which make the feedstock difficult to be converted into biodiesel using basic catalyst. Therefore, in this study, a solid acid, RHA-SO3H catalyst was synthesized by sulfonating rice husk ash (RHA) with concentrated sulfuric acid. The RHA-SO3H prepared was characterized with TGA, FTIR, BET, XRD, FE-SEM, and Hammett indicators (methyl red, bromophenol blue, and crystal violet). PDC was found to have about 11.3 wt. % oil recovered after 1 hour extraction using ultrasound method. The presence of sulfonate group was observed in IR spectrum, and the surface area of RHA-SO3H was reduced to 37 m2.g-1 after impregnation of sulfonate group. The RHA-SO3H catalyst showed that it can work for both esterification of free fatty acid which is present in PDC-oil, and transesterification of triglycerides into methyl ester. The results showed highest methyl ester content of 70.2 wt.% at optimal conditions, which was 6 wt.% catalyst amount, methanol to oil molar ratio of 17:1 for 5 hours at 120 °C.

  6. Rice husks as a sustainable source of nanostructured silicon for high performance Li-ion battery anodes

    PubMed Central

    Liu, Nian; Huo, Kaifu; McDowell, Matthew T.; Zhao, Jie; Cui, Yi

    2013-01-01

    The recovery of useful materials from earth-abundant substances is of strategic importance for industrial processes. Despite the fact that Si is the second most abundant element in the Earth's crust, processes to form Si nanomaterials is usually complex, costly and energy-intensive. Here we show that pure Si nanoparticles (SiNPs) can be derived directly from rice husks (RHs), an abundant agricultural byproduct produced at a rate of 1.2 × 108 tons/year, with a conversion yield as high as 5% by mass. And owing to their small size (10–40 nm) and porous nature, these recovered SiNPs exhibits high performance as Li-ion battery anodes, with high reversible capacity (2,790 mA h g−1, seven times greater than graphite anodes) and long cycle life (86% capacity retention over 300 cycles). Using RHs as the raw material source, overall energy-efficient, green, and large scale synthesis of low-cost and functional Si nanomaterials is possible. PMID:23715238

  7. Synthesis of carbon encapsulated SiO2 nanoparticles from rice husk and its application in solar to steam conversion

    NASA Astrophysics Data System (ADS)

    Mufti, Nandang; Lestari, Nurhayati A.; Suciani, Erlin; Fuad, Abdulloh; Diantoro, Markus

    2016-03-01

    Steam is important in many technological applications including sterilization of medical devices, cleaning, and power generating. In general, steam can be produced by boiling water at high temperature. In new technology, solar can convert water directly into steam even at low temperature by using nanoparticles. In this research we study solar to steam conversion of carbon encapsulated SiO2 nanoparticles (SiO2@C) synthesized from rice husk. SiO2 nanoparticles were synthesized using alkali extraction and sol-gel methods. While synthesis of carbon encapsulated SiO2 nanoparticles was done by sonochemical method with glucose as source of carbon. The samples have been characterized by XRF, SEM-EDX, and XRD. The effectivity of solar steam conversion performed by measuring time dependent of temperature and pressure. XRF and XRD results shown that SiO2 nanoparticles have purity of 97.2% inn amorphous phase. Carbon encapsulated SiO2 nanoparticles (SiO2@C) have successfully synthesized indicating by NaOH base test. The morphology of SiO2@C is agglomerated with average particle size around 20 nm. The measurement of solar to steam conversion showed that increasing carbon concentration of SiO2@C rises steam production with indicated by increasing temperature and pressure of steam.

  8. Potentiometric stripping analysis of antimony based on carbon paste electrode modified with hexathia crown ether and rice husk.

    PubMed

    Gadhari, Nayan S; Sanghavi, Bankim J; Srivastava, Ashwini K

    2011-10-03

    An electrochemical method based on potentiometric stripping analysis (PSA) employing a hexathia 18C6 (HT18C6) and rice husk (RH) modified carbon paste electrode (HT18C6-RH-CPE) has been proposed for the subnanomolar determination of antimony. The characterization of the electrode surface has been carried out by means of scanning electron microscopy, cyclic voltammetry, electrochemical impedance spectroscopy and chronocoulometry. By employing HT18C6-RH-CPE, a 12-fold enhancement in the PSA signal (dt/dE) was observed as compared to plain carbon paste electrode (PCPE). Under the optimized conditions, dt/dE (sV(-1)) was proportional to the Sb(III) concentration in the range of 1.42×10(-8) to 6.89×10(-11)M (r=0.9944) with the detection limit (S/N=3) of 2.11×10(-11)M. The practical analytical utilities of the modified electrode were demonstrated by the determination of antimony in pharmaceutical formulations, human hair, sea water, urine and blood serum samples. The prepared modified electrode showed several advantages, such as simple preparation method, high sensitivity, very low detection limit and excellent reproducibility. Moreover, the results obtained for antimony analysis in commercial and real samples using HT18C6-RH-CPE and those obtained by inductively coupled plasma-atomic emission spectrometry (ICP-AES) are in agreement at the 95% confidence level.

  9. Effect of Rice Husk Ash Insulation Powder on the Reoxidation Behavior of Molten Steel in Continuous Casting Tundish

    NASA Astrophysics Data System (ADS)

    Kim, Tae Sung; Chung, Yongsug; Holappa, Lauri; Park, Joo Hyun

    2017-06-01

    Rice husk ash (RHA) has been widely used as an insulation powder in steel casting tundish. Its effect on the reoxidation of molten steel in tundish as well as on the corrosion of magnesia refractory was investigated. The reoxidation of the steel, indicated by an oxygen pickup, was progressed by increasing the ratio of RHA to the sum of RHA and carryover ladle slag ( R ratio) greater than about 0.2. The increase of the silica activity in the slag layer promoted the self-dissociation of SiO2 from the slag layer into the molten steel, resulting in the silicon and oxygen pickup as the R ratio increased. The total number of reoxidation inclusions dramatically increased and the relative fraction of Al2O3-rich inclusions increased by increasing the R ratio. Hence, the reoxidation of molten steel in tundish might become more serious due to the formation of alumina-rich inclusions as the casting sequence increases. MgO in the refractory directly dissolved into the molten slag layer without forming any intermediate compound layer ( e.g., spinel), which is a completely different situation from the general slag-refractory interfacial reaction. A flow was possibly induced by the bursting of gas bubbles at the ash-slag (-refractory) interface, since the silica in the RHA powder continuously dissolved into the molten slag pool. Thus, the RHA insulation powder has a negative effect on the corrosion of MgO refractory.

  10. Arsenic and chromium removal from water using biochars derived from rice husk, organic solid wastes and sewage sludge.

    PubMed

    Agrafioti, Evita; Kalderis, Dimitrios; Diamadopoulos, Evan

    2014-01-15

    Biochars derived from rice husk, the organic fraction of municipal solid wastes and sewage sludge, as well as a sandy loam soil, were used as adsorbents for As(V), Cr(III) and Cr(VI) removal from aqueous solutions. The kinetic study showed that sorption can be well described by the pseudo-second order kinetic model, while simulation of sorption isotherms gave better fit for the Freundlich model. The materials examined removed more than 95% of the initial Cr(III). However, removal rates for As(V) and Cr(VI) anions were significantly lower. Biochar derived from sewage sludge was efficient in removing 89% of Cr(VI) and 53% of As(V). Its ash high Fe2O3 content may have enhanced metal adsorption via precipitation. Soil was the most effective material for the removal of As(V), yet it could not strongly retain metal anions compared to biochars, as a significant amount of the adsorbed metal was released during desorption experiments.

  11. Rice husks as a sustainable source of nanostructured silicon for high performance Li-ion battery anodes.

    PubMed

    Liu, Nian; Huo, Kaifu; McDowell, Matthew T; Zhao, Jie; Cui, Yi

    2013-01-01

    The recovery of useful materials from earth-abundant substances is of strategic importance for industrial processes. Despite the fact that Si is the second most abundant element in the Earth's crust, processes to form Si nanomaterials is usually complex, costly and energy-intensive. Here we show that pure Si nanoparticles (SiNPs) can be derived directly from rice husks (RHs), an abundant agricultural byproduct produced at a rate of 1.2 × 10(8) tons/year, with a conversion yield as high as 5% by mass. And owing to their small size (10-40 nm) and porous nature, these recovered SiNPs exhibits high performance as Li-ion battery anodes, with high reversible capacity (2,790 mA h g(-1), seven times greater than graphite anodes) and long cycle life (86% capacity retention over 300 cycles). Using RHs as the raw material source, overall energy-efficient, green, and large scale synthesis of low-cost and functional Si nanomaterials is possible.

  12. Rice husks as a sustainable source of nanostructured silicon for high performance Li-ion battery anodes

    NASA Astrophysics Data System (ADS)

    Liu, Nian; Huo, Kaifu; McDowell, Matthew T.; Zhao, Jie; Cui, Yi

    2013-05-01

    The recovery of useful materials from earth-abundant substances is of strategic importance for industrial processes. Despite the fact that Si is the second most abundant element in the Earth's crust, processes to form Si nanomaterials is usually complex, costly and energy-intensive. Here we show that pure Si nanoparticles (SiNPs) can be derived directly from rice husks (RHs), an abundant agricultural byproduct produced at a rate of 1.2 × 108 tons/year, with a conversion yield as high as 5% by mass. And owing to their small size (10-40 nm) and porous nature, these recovered SiNPs exhibits high performance as Li-ion battery anodes, with high reversible capacity (2,790 mA h g-1, seven times greater than graphite anodes) and long cycle life (86% capacity retention over 300 cycles). Using RHs as the raw material source, overall energy-efficient, green, and large scale synthesis of low-cost and functional Si nanomaterials is possible.

  13. Ceria and titania incorporated silica based catalyst prepared from rice husk: adsorption and photocatalytic studies of methylene blue.

    PubMed

    Adam, Farook; Muniandy, Lingeswarran; Thankappan, Radhika

    2013-09-15

    Titania and ceria incorporated rice husk silica based catalyst was synthesized via sol-gel method using CTAB and glycerol as surface directing agents at room temperature and labeled as RHS-50Ti10Ce. The catalyst was used to study the adsorption and photodegradation of methylene blue (MB) under UV irradiation. The powder XRD pattern of RHS-50Ti10Ce was much broader (2θ=25-30°) than that of the parent RHS (2θ=22°). The catalyst exhibited type IV isotherm with H3 hysteresis loop, and the TEM images showed partially ordered pore arrangements. The TGA-DTG thermograms confirmed the complete removal of the templates after calcination at 500°C. RHS-50Ti10Ce exhibited excellent adsorption capability with more than 99% removal of MB from a 40 mg L(-1) solution in just 15 min. It also decolorized an 80 mg L(-1) MB solution under UV irradiation in 210 min, which was comparable with the commercialized pure anatase TiO2.

  14. Chemical and microbiological characteristics of rice husk bedding having distinct depths and used for growing-finishing swine.

    PubMed

    Corrêa, E K; Bianchi, I; Perondi, A; de los Santos, J R G; Corrêa, M N; Castilhos, D D; Gil-Turnes, C; Lucia, T

    2009-11-01

    This study compared the effects of different bedding depths on the chemical and microbiological characteristics of the bedding material used to raise pigs during growing and finishing. The experiment was conducted in two pens housing 5 pigs from 60 to 145 days of age, with rice husk beddings 0.50 or 0.25 m deep. Four lots of pigs (replicates) were raised over time in each bedding depth: each bedding was used by two consecutive lots. Bedding samples were collected quarterly to determine the most probable number (MPN) of thermophilic and mesophilic bacteria, fungi and actinomycetes. Contents of N, P, K, C, organic, mineral and dry matter, C:N ratio and pH were also determined. The MPN of thermophilic bacteria was higher for the 0.50 m than for the 0.25 m bedding (p<0.05). The compost of 0.25 m deep bedding had a higher N, P and K content than that from the 0.50 m bedding (p<0.05). Thus, the use of the 0.25 m deep bedding would be recommended due to its greater agronomical value in comparison with the deeper bedding.

  15. Magnetic Phase Development of Iron Oxide-SiO2 Aerogel and Xerogel Prepared using Rice Husk Ash as Precursor

    NASA Astrophysics Data System (ADS)

    Maamur, K. N.; Jais, U. S.; Yahya, S. Y. S.

    2010-03-01

    This study is aimed to produce iron incorporated silica aerogel and xerogel from rice husk ash. Two sol—gel chemistry routes have been used to synthesize both samples. Iron in the form of hydrated iron nitrate with compositions in the range of 3-17 wt% (Fe2O3/Fe2O3+SiO2) were used as iron source. For aerogel samples, iron was added at the solution level whereas for xerogel samples, iron was added after the gelation. The synthesis of iron doped aerogel was done by supercritical drying at temperature about 250° C and pressure of about 5.9 MPa (850 psi) while xerogel was formed by drying the aquagel in an oven at 110° C for 24 hours. The iron doped aerogel and xerogel composites were further heated to various temperatures to obtain the magnetic phase. Results show that the only sample that signifies the presence of maghemite (γ-Fe2O3) is the aerogel sample doped with 7.3 wt% iron at temperature 1100° C while other samples show the presence of magnetite.

  16. Rice husk ash sorbent doped with copper for simultaneous removal of SO2 and NO: optimization study.

    PubMed

    Lau, Lee Chung; Lee, Keat Teong; Mohamed, Abdul Rahman

    2010-11-15

    In order to reduce the negative impact of coal utilization for energy generation, the pollutants present in the flue gas of coal combustion such as sulfur dioxide (SO(2)) and nitrogen oxide (NO) must be effectively removed before releasing to the atmosphere. Thus in this study, sorbent prepared from rice husk ash that is impregnated with copper is tested for simultaneous removal of SO(2) and NO from simulated flue gas. The effect of various sorbent preparation parameters; copper loading, RHA/CaO ratio, hydration period and NaOH concentration on the sorbent desulfurization/denitrification capacity was studied using Design-Expert Version 6.0.6 software. Specifically, Central Composite Design (CCD) coupled with Response Surface Method (RSM) was used. Significant individual parameters that affect the sorbent capacity are copper loading and NaOH concentration. Apart from that, interaction between the following parameters was also found to have significant effect; copper loading, RHA/CaO ratio and NaOH concentration. The optimum sorbent preparation condition for this study was found to be 3.06% CuO loading, RHA/CaO ratio of 1.41, 8.05 h of hydration period and NaOH concentration of 0.80 M. Sorbent characterization using SEM, XRD and surface area analysis were used to describe the effect of sorbent preparation parameters on the desulfurization/denitrification activity.

  17. The reaction between rice husk ash and Ca(OH){sub 2} solution and the nature of its product

    SciTech Connect

    Yu, Q.; Sawayama, K.; Sugita, S.; Shoya, M.; Isojima, Y.

    1999-01-01

    In this study it was confirmed that, at temperatures around 40 C and in the presence of water, the amorphous silica contained in rice husk ash (RHA) can react with Ca(OH){sub 2} to form one kind of C-S-H gel (Ca{sub 1.5}SiO{sub 3.5}{center_dot}xH{sub 2}O). The C-S-H gel looks like flocs in morphology, with a porous structure and large specific surface. The average particle diameter of the reaction product, ranging from 4.8 to 7.9 {micro}m, varies slightly with the condition under which the reaction occurs. When the product is heated, it gradually loses the water that exists in it, but it maintains an amorphous form up to 750 C. Above 780 C it begins to transform to crystalline CaSiO{sub 3}. One of the main reasons for the improvement of concrete properties upon addition of RHA possibly may be attributed to the formation of more C-S-H gel and less portlandite in concrete due to the reaction occurring between RHA and the Ca{sup 2+}, OH{sup {minus}} ions, or Ca(OH){sub 2} in hydrating cement.

  18. Reinforcement of natural rubber/high density polyethylene blends with electron beam irradiated liquid natural rubber-coated rice husk

    NASA Astrophysics Data System (ADS)

    Chong, E. L.; Ahmad, Ishak; Dahlan, H. M.; Abdullah, Ibrahim

    2010-08-01

    Coating of rice husk (RH) surface with liquid natural rubber (LNR) and exposure to electron beam irradiation in air were studied. FTIR analysis on the LNR-coated RH (RHR) exposed to electron beam (EB) showed a decrease in the double bonds and an increase in hydroxyl and hydrogen bonded carbonyl groups arising from the chemical interaction between the active groups on RH surface with LNR. The scanning electron micrograph showed that the LNR formed a coating on the RH particles which transformed to a fine and clear fibrous layer at 20 kGy irradiation. The LNR film appeared as patches at 50 kGy irradiation due to degradation of rubber. Composites of natural rubber (NR)/high density polyethylene (HDPE)/RHR showed an optimum at 20-30 kGy dosage with the maximum stress, tensile modulus and impact strength of 6.5, 79 and 13.2 kJ/m 2, respectively. The interfacial interaction between the modified RH and TPNR matrix had improved on exposure of RHR to e-beam at 20-30 kGy dosage.

  19. Thermodynamic and kinetic studies of biosorption of iron and manganese from aqueous medium using rice husk ash

    NASA Astrophysics Data System (ADS)

    Adekola, F. A.; Hodonou, D. S. S.; Adegoke, H. I.

    2016-11-01

    The adsorption behavior of rice husk ash with respect to manganese and iron has been studied by batch methods to consider its application for water and waste water treatment. The optimum conditions of adsorption were determined by investigating the effect of initial metal ion concentration, contact time, adsorbent dose, pH value of aqueous solution and temperature. Adsorption equilibrium time was observed at 120 min. The adsorption efficiencies were found to be pH dependent. The equilibrium adsorption experimental data were found to fit the Langmuir, Freundlich and Temkin isotherms for iron, but fitted only Langmuir isotherm for manganese. The pseudo-second order kinetic model was found to describe the manganese and iron kinetics more effectively. The thermodynamic experiment revealed that the adsorption processes involving both metals were exothermic. The adsorbent was finally applied to typical raw water with initial manganese and iron concentrations of 3.38 mg/l for Fe and 6.28 mg/l, respectively, and the removal efficiency was 100 % for Mn and 70 % for Fe. The metal ions were desorbed from the adsorbent using 0.01 M HCl, it was found to quantitatively remove 67 and 86 % of Mn and Fe, respectively, within 2 h. The results revealed that manganese and iron are considerably adsorbed on the adsorbent and could be an economic method for the removal of these metals from aqueous solutions.

  20. Synthesis of ZSM-5 zeolite from coal fly ash and rice husk: characterization and application for partial oxidation of methane to methanol

    NASA Astrophysics Data System (ADS)

    Krisnandi, Y. K.; Yanti, F. M.; Murti, S. D. S.

    2017-04-01

    Indonesian fly ash (SiO2/Al2O3 mole ratio = 3.59) was used together with rice husk (SiO2 92%) as raw material for mesoporous ZSM-5 zeolite synthesis. Prior being used, coal fly ash and rice husk were subjected to pre-treatment in order to extract silicate (SiO4 4-) and aluminate (AlO4 5-) and to remove the impurities. Then the ZSM-5 zeolite were synthesized through hydrothermal treatment using two types of templates (TPAOH and PDDA). The as-synthesized ZSM-5 was characterized using FTIR, XRD, SEM-EDX, and BET. The result of FTIR showed peaks at 1250-950 cm-1 (v asymetric T-O), 820-650 cm-1 (v symetric T-O), and at 650-500 cm-1 confirming the presence of the five number ring of the pentasil structure. The result of XRD showed the appearance of certain peaks in the position 2 theta between 7-9° and 22-25° indicative of ZSM-5 structure, but also showed the pattern of low intensity magnetite and hematite. The SEM image showed the rough surface of hexagonal crystals from ZSM-5 structure, indicative of mesoporosity in the structure. EDX result showed Si/Al ratio of 20, while surface area analysis gave SA of 43.16. The ZSM-5 zeolites then was modified with cobalt oxide through impregnation method. The catalytic activity as heterogeneous catalysts in partial oxidation of methane was tested. The result showed that hence the catalytic activity of ZSM-5 and Co/ZSM-5 from fly ash and rice husk were still inferior compared to the pro-analysis sourced-counterpart, they were potential to be used as catalyst in the partial oxidation of methane to methanol.

  1. Analysis of SO{sub 2} sorption capacity of rice husk ash (RHA)/CaO/NaOH sorbents using response surface methodology (RSM): untreated and pretreated RHA

    SciTech Connect

    Irvan Dahlan; Keat Teong Lee; Azlina Harun Kamaruddin; Abdul Rahman Mohamed

    2008-03-01

    The SO{sub 2} sorption capacity (SSC) of sorbents prepared from rice husk ash (RHA) with NaOH as additive was studied in a fixed-bed reactor. Rice husk ash is produced by burning rice husks at about 300{sup o}C and was chosen as a source of siliceous material, abundantly available in Malaysia. The sorbents were prepared using a water hydration method by slurrying RHA, CaO, and NaOH. Response surface methodology (RSM) based on four-variable central composite face centered design (CCFCD) was employed in the synthesis of the sorbents. The correlation between the sorbent SSC (as response) with four independent sorbent preparation variables, i.e. hydration period, RHA/CaO ratio, NaOH amount, and drying temperature, were presented as empirical mathematical models. Among all the variables studied, the amount of NaOH used was found to be the most significant variable affecting the SSC of the sorbents prepared. The SSC for sorbent prepared with the addition of NaOH was found to be significantly higher than sorbents prepared without NaOH. This is probably because NaOH is a deliquescent material, and its existence increases the amount of water collected on the surface of the sorbent, a condition required for sorbent-SO{sub 2} reaction to occur at low temperature. The effect of further treatment of RHA at 600{sup o}C was also investigated. Although pretreated RHA sorbents demonstrated higher SSC as compared to untreated RHA sorbents, nevertheless, at optimum conditions, sorbents prepared from untreated RHA was found to be more favorable due to practical and economic concerns. 33 refs., 3 figs., 1 tab.

  2. The Application of a Representative Volume Element (RVE) Model for the Prediction of Rice Husk Particulate-Filled Polymer Composite Properties

    NASA Astrophysics Data System (ADS)

    Pochanard, Pandhita

    Polymer composite is one of the most widely used materials with application in multiple industries. However, its versatility and subsequent rise in consumption have prompted an increase in research on alternative materials to address the associated environmental concerns. The forefront of this investigation is on the potential use of biocomposite materials as a more sustainable replacement to the traditional polymer composite. Consequently, the ability to apply a theoretical model capable of replicating the microstructures of particulate-filled composite would make a very powerful analytical tool for material design. To address these requirements, this thesis applies a representative volume element (RVE) model for the investigation on the potential use of rice husk particulate-filled polymer composite as alternative material in non-critical application. In this work, rice husk powder (RHP) was used with epoxy for the fabrication of biocomposite samples with 0%, 10% and 30% RHP volume percentage. It was observed that a 10% increase in RHP did not affect the composite elastic property, but led to 15% and 20% decrease in yield stress and tensile strength, respectively. Further increase in RHP to 30% volume percentage also led to 8%, 21% and 28% reduction in Young's modulus, yield stress and tensile strength, respectively. Additionally, the material's responses to uniaxial loading predicted by the RVE model were found to be in reasonable agreement with the analytical and experimental results. No coupling agent was used in this study. The results of this present study suggested that rice husk powder could be used to reduce the composite raw material costs by replacing the more expensive polymer content with agricultural waste products without significant compromise to the composite's mechanical properties.

  3. Synthesis optimization of oil palm empty fruit bunch and rice husk biochars for removal of imazapic and imazapyr herbicides.

    PubMed

    Yavari, Saba; Malakahmad, Amirhossein; Sapari, Nasiman B; Yavari, Sara

    2017-05-15

    Imidazolinones are a family of herbicides that are used to control a broad range of weeds. Their high persistence and leaching potential make them probable risk to the ecosystems. In this study, biochar, the biomass-derived solid material, was produced from oil palm empty fruit bunches (EFB) and rice husk (RH) through pyrolysis process. Feedstock and pyrolysis variables can control biochar sorption capacity. Therefore, the present study attempts to evaluate effects of three pyrolysis variables (temperature, heating rate and retention time) on abilities of biochars for removal of imazapic and imazapyr herbicides from soil. Response surface methodology (RSM) was used for optimizing the variables to achieve maximum sorption performance of the biochars. Experimental data were interpreted accurately by quadratic models. Based on the results, sorption capacities of both biochars raised when temperature decreased to 300 °C, mainly because of increased biochars effective functionality in sorption of polar molecules. Heating rate of 3°C/min provided optimum conditions to maximize the sorption capacities of both biochars. Retention time of about 1 h and 3 h were found to be the best for EFB and RH biochars, respectively. EFB biochar was more efficient in removal of the herbicides, especially imazapyr due to its chemical composition and higher polarity index (0.42) rather than RH biochar (0.39). Besides, higher cation exchange capacity (CEC) values of EFB biochar (83.90 cmolc/kg) in comparison with RH biochar (70.73 cmolc/kg) represented its higher surface polarity effective in sorption of the polar herbicides. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Preparation and Characterization of Impregnated Commercial Rice Husks Activated Carbon with Piperazine for Carbon Dioxide (CO2) Capture

    NASA Astrophysics Data System (ADS)

    Masoum Raman, S. N.; Ismail, N. A.; Jamari, S. S.

    2017-06-01

    Development of effective materials for carbon dioxide (CO2) capture technology is a fundamental importance to reduce CO2 emissions. This work establishes the addition of amine functional group on the surface of activated carbon to further improve the adsorption capacity of CO2. Rice husks activated carbon were modified using wet impregnation method by introducing piperazine onto the activated carbon surfaces at different concentrations and mixture ratios. These modified activated carbons were characterized by using X-Ray Diffraction (XRD), Brunauer, Emmett and Teller (BET), Fourier Transform Infrared Spectroscopy (FTIR) and Field Emission Scanning Electron Microscopy (FESEM). The results from XRD analysis show the presence of polyethylene butane at diffraction angles of 21.8° and 36.2° for modified activated carbon with increasing intensity corresponding to increase in piperazine concentration. BET results found the surface area and pore volume of non-impregnated activated carbon to be 126.69 m2/g and 0.081 cm3/g respectively, while the modified activated carbons with 4M of piperazine have lower surface area and pore volume which is 6.77 m2/g and 0.015 cm3/g respectively. At 10M concentration, the surface area and pore volume are the lowest which is 4.48 m2/g and 0.0065 cm3/g respectively. These results indicate the piperazine being filled inside the activated carbon pores thus, lowering the surface area and pore volume of the activated carbon. From the FTIR analysis, the presence of peaks at 3312 cm-1 and 1636 cm-1 proved the existence of reaction between carboxyl groups on the activated carbon surfaces with piperazine. The surface morphology of activated carbon can be clearly seen through FESEM analysis. The modified activated carbon contains fewer pores than non-modified activated carbon as the pores have been covered with piperazine.

  5. Acid dye removal: comparison of surfactant-modified mesoporous FSM-16 with activated carbon derived from rice husk.

    PubMed

    Mohamed, Mohamed Mokhtar

    2004-04-01

    Cetyltrimethylammonium bromide (CTAB)-modified mesoporous molecular sieve FSM-16, prepared by a hydrothermal process (373 K, 3 days), was tested as an adsorbent for acid dye (acid yellow, AY, and acid blue, AB) removal in comparison with as-prepared FSM-16 and activated carbon (AC) derived from rice husk (50 vol% H3PO4, 773 K, 2.5 h). The adsorption isotherms, sorption kinetics, and pH effects upon acid dyes sorption on the adsorbents were thoroughly investigated. The structures of different adsorbents were characterized by XRD, FTIR spectroscopy, N2 adsorption measurements, and thermogravimetric (TG) analysis. It was found that the ultimate capacity of the adsorbents varied in the order FSM-16 > modified FSM-16 > AC and followed first-order rate kinetics. The adsorption isotherm of acid dyes on FSM-16 is of type IV, according to the IUPAC classification, drastically different from that of CTAB/FSM-16, which showed a type I isotherm. The latter sample had better adsorption performance at low concentration of acid dyes than the former. As compared to activated carbon of microporous character, the CTAB/FSM-16 sample achieved higher performance at low concentrations. This was due to the successful narrowing of the pore opening of FSM-16 using CTAB with maintenance of a considerable portion of the pore volume. Powder XRD and N2 adsorption studies of the CTAB/FSM-16 material indicated that the textural properties of the support were preserved during the hydrothermal synthesis and that the channels remained accessible, despite a significant reduction in surface area (ca. 26%). TG studies, on the other hand, confirmed that the modified material presented a higher hydrophobicity than that of the CTAB-free FSM-16 sample.

  6. Feasibility of CO₂/SO₂ uptake enhancement of calcined limestone modified with rice husk ash during pressurized carbonation.

    PubMed

    Chen, Huichao; Zhao, Changsui; Ren, Qiangqiang

    2012-01-01

    The calcination/carbonation cycle using calcium-based sorbents appears to be a viable method for carbon dioxide (CO₂) capture from combustion gases. Recent attempts to improve the CO₂/SO₂ uptake of a calcium-based sorbent modified by using rice husk ash (RHA) in the hydration process have succeeded in enhancing its effectiveness. The optimal mole ratio of RHA to calcined limestone (M(Si/Ca)) was adjusted to 0.2. The cyclic CO₂ capture characteristics and the SO₂ uptake activity of the modified sorbent were evaluated in a calcination/pressurized carbonation reactor system. Scanning electron microscope (SEM) images and X-ray diffraction (XRD) spectrum of the sorbent were also taken to supplement the study. The results showed that the carbonation conversion was greatly increased for the sorbent with M(Si/Ca) ratio of 0.2. For this sorbent formulation the optimal operating conditions were 700-750 °C and 0.5-0.7 MPa. CO₂ absorption was not proportional to CO₂ concentration in the carbonation atmosphere, but was directly related to reaction time. The CO₂ uptake decreased in the presence of SO₂. SO₂ uptake increased, and the total calcium utilization was maintained over multiple cycles. Analysis has shown that the silicate component is evenly or well distributed, and this serves as a framework to prevent sintering, thus preserving the available microstructure for reaction. The sorbent also displayed high activity to SO₂ absorption and could be used to capture CO₂ and SO₂ simultaneously. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Rice husks and their hydrochars cause unexpected stress response in the nematode Caenorhabditis elegans: reduced transcription of stress-related genes.

    PubMed

    Chakrabarti, Shumon; Dicke, Christiane; Kalderis, Dimitrios; Kern, Jürgen

    2015-08-01

    Currently, char substrates gain a lot of interest since soils amended with such substrates are being discussed to increase in fertility and productivity, water retention, and mitigation of greenhouse gases. Char substrates can be produced by carbonization of organic matter. Among different process conditions, temperature is the main factor controlling the occurrence of organic and inorganic contaminants such as phenols and furfurals, which may affect target and non-target organisms. The hydrochar produced at 200 °C contained both furfural and phenol with concentrations of 282 and 324 mg kg(-1) in contrast to the 300 °C hydrochar, which contained only phenol with a concentration of 666 mg kg(-1). By washing with acetone and water, these concentrations were significantly reduced. In this study, the potential toxic effects of hydrochars on the free-living nematode Caenorhabditis elegans were investigated via gene transcription studies using the following four matrices: (i) raw rice husk, (ii) unwashed rice char, (iii) acetone/water washed rice char, and (iv) the wash water of the two rice chars produced at 200 and 300 °C via hydrothermal carbonization (HTC). Furthermore, genetically modified strains, where the green fluorescent protein (GFP) gene sequence is linked to a reporter gene central in specific anti-stress regulations, were also exposed to these matrices. Transgenic worms exposed to hydrochars showed very weak, if any, fluorescence, and expression of the associated RNAs related to stress response and biotransformation genes was surprisingly downregulated. Similar patterns were also found for the raw rice husk. It is hypothesized that an unidentified chemical trigger exists in the rice husk, which is not destroyed during the HTC process. Therefore, the use of GFP transgenic nematode strains cannot be recommended as a general rapid monitoring tool for farmers treating their fields with artificial char. However, it is hypothesized that the observed reduced

  8. Synthesis of biogenic silicon/silica (Si/SiO2) nanocomposites from rice husks and wheat bran through various microorganisms

    NASA Astrophysics Data System (ADS)

    Kaur, Taranjot; Pal Singh, Gurwinder; Kaur, Gurneet; Kaur, Sukhvir; Gill, Prabhjot Kaur

    2016-08-01

    Biosilification is an economically viable, energy saving and green approach for the commercial scale synthesis of oxide nanomaterials. The room temperature synthesis of oxide nanocomposites from cost effective agro-based waste is a particular example of biosilification. In this study, synthesis of Si/SiO2 nanocomposites from inexpensive agro-based waste material i.e. rice husks (RH) and wheat bran (WB) has been carried out by means of various eukaryotic microorganisms, i.e. Actinomycete, Fusarium oxysporum, Aspergillus niger, Trichoderma sp. and Penicillium sp., under ambient conditions. The XRD diffrectrograms represents that the synthesized nanomaterials exhibits silicon, amorphous silica and other crystal arrays such as cristobalite, trydimite and quartz, depending upon the type microorganism and time period used for extraction. All of the aforesaid microorganism bio transformed the naturally occurring amorphous silica to crystalline structures within the period of 24 h. However, the Actinomycete and Trichoderma sp. took 48 h in case of rice husks for biotransformation of naturally occurring plant silica to crystalline nanocomposite. While in case of wheat bran, Actinomycete and Trichoderma sp. took 24 h for biotransformation. The extracted nanocomposites exhibits band edge in the range 230-250 nm and blue emission. The procedure described in study can be used for commercial level production of Si/SiO2 nanocomposites from agro based waste materials.

  9. Screening of filamentous fungi to produce xylanase and xylooligosaccharides in submerged and solid-state cultivations on rice husk, soybean hull, and spent malt as substrates.

    PubMed

    da Silva Menezes, Bruna; Rossi, Daniele Misturini; Ayub, Marco Antônio Záchia

    2017-03-01

    We investigated the enzymatic complex produced by selected fungi strains isolated from the environment using the agro-industrial residues rice husk, soybean hull, and spent malt as substrates. Microbial growth was carried out in solid-state cultivation (SSC) and in submerged cultivations (SC) and the enzymatic activities of xylanase, cellulase, β-xylosidase, and β-glucosidase were determined. All substrates were effective in inducing enzymatic activities, with one strain of Aspergillus brasiliensis BLf1 showing maximum activities for all enzymes, except for cellulases. Using this fungus, the enzymatic activities of xylanase, cellulase, and β-glucosidase were generally higher in SSC compared to SC, producing maxima activities of 120.5, 25.3 and 47.4 U g(-1) of dry substrate, respectively. β-xylosidase activity of 28.1 U g(-1) of dry substrate was highest in SC. Experimental design was carried out to optimize xylanase activity by A. brasiliensis BLf1 in SSC using rice husk as substrate, producing maximum xylanase activity 183.5 U g(-1) dry substrate, and xylooligosaccharides were produced and characterized. These results suggest A. brasiliensis BLf1 can be used to produce important lytic enzymes to be applied in the preparation of xylooligosaccharides.

  10. Effect of mixing ratio of food waste and rice husk co-digestion and substrate to inoculum ratio on biogas production.

    PubMed

    Haider, Muhammad Rizwan; Zeshan; Yousaf, Sohail; Malik, Riffat Naseem; Visvanathan, Chettiyappan

    2015-08-01

    Aim of this study was to find out suitable mixing ratio of food waste and rice husk for their co-digestion in order to overcome VFA accumulation in digestion of food waste alone. Four mixing ratios of food waste and rice husk with C/N ratios of 20, 25, 30 and 35 were subjected to a lab scale anaerobic batch experiment under mesophilic conditions. Highest specific biogas yield of 584L/kgVS was obtained from feedstock with C/N ratio of 20. Biogas yield decreased with decrease in food waste proportion. Further, fresh cow dung was used as inoculum to investigate optimum S/I ratio with the selected feedstock. In experiment 2, feedstock with C/N ratio 20 was subjected to anaerobic digestion at five S/I ratios of 0.25, 0.5, 1.0, 1.5 and 2.0. Specific biogas yield of 557L/kgVS was obtained at S/I ratio of 0.25. However, VFA accumulation occurred at higher S/I ratios due to higher organic loadings. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Low-cost nanoparticles sorbent from modified rice husk and a copolymer for efficient removal of Pb(II) and crystal violet from water.

    PubMed

    Masoumi, Arameh; Hemmati, Khadijeh; Ghaemy, Mousa

    2016-03-01

    In this work, preparation of adsorbent nanoparticles based on treated low-value agricultural by-product rice husk (TARH), and poly(methylmethacrylate-co-maleic anhydride), poly(MMA-co-MA), is reported for the removal of Pb(II) ion and Crystal violet dye from water. The prepared adsorbent was characterized by FT-IR, SEM, AFM, DLS, BET and Zeta potential. The metal ion adsorption capability was determined for rice husk (RH), TARH, crosslinked poly(MMA-co-MA) (CNR), and CNR@TARH nanoparticles. Different factors affecting the adsorption of Pb(II) such as pH, contact time, initial metal ion concentration and also temperature were studied to investigate adsorption isotherms, kinetics and thermodynamics. For the four tested adsorption isotherm models, the equilibrium sorption data for CNR@TARH nanoparticles obeyed the Langmuir isotherm equation with maximum sorption capacity of 93.45 mg g(-1). The kinetic adsorption data fitted best the Lagergren pseudo-second order model. Regeneration of adsorbent was easily performed by adsorption/desorption experiments followed for 4 cycles. Finally, the ability of the nanoparticles to remove Crystal violet dye from aqueous solution was also investigated by varying the initial dye concentration, pH and immersion time and the adsorption mechanism followed the second-order kinetic model.

  12. Artificial neural network (ANN) modeling of adsorption of methylene blue by NaOH-modified rice husk in a fixed-bed column system.

    PubMed

    Chowdhury, Shamik; Saha, Papita Das

    2013-02-01

    In this study, rice husk was modified with NaOH and used as adsorbent for dynamic adsorption of methylene blue (MB) from aqueous solutions. Continuous removal of MB from aqueous solutions was studied in a laboratory scale fixed-bed column packed with NaOH-modified rice husk (NMRH). Effect of different flow rates and bed heights on the column breakthrough performance was investigated. In order to determine the most suitable model for describing the adsorption kinetics of MB in the fixed-bed column system, the bed depth service time (BDST) model as well as the Thomas model was fitted to the experimental data. An artificial neural network (ANN)-based model was also developed for describing the dynamic dye adsorption process. An extensive error analysis was carried out between experimental data and data predicted by the models by using the following error functions: correlation coefficient (R(2)), average relative error, sum of the absolute error and Chi-square statistic test (χ(2)). Results show that with increasing bed height and decreasing flow rate, the breakthrough time was delayed. All the error functions yielded minimum values for the ANN model than the traditional models (BDST and Thomas), suggesting that the ANN model is the most suitable model to describe the fixed-bed adsorption of MB by NMRH. It is also more rational and reliable to interpret dynamic dye adsorption data through a process of ANN architecture.

  13. Reduction in time required for synthesis of high specific surface area silica from pyrolyzed rice husk by precipitation at low pH.

    PubMed

    Li, Dawei; Chen, Dengyu; Zhu, Xifeng

    2011-07-01

    Porous silica with a high specific surface area (SSA) was prepared from pyrolyzed rice husk (PRH) by adding H(3)PO(4) to sodium silicate solution (SSS) until the pH values of 5.7, 5.0, 4.1 and 3.2 were achieved. The preparation process involved producing SSS from PRH, forming silica-polyethylene glycol (PEG) composites using SSS, H(3)PO(4) and PEG, and calcinating the composites. The required preparation time was below 10h, and the SSA of the sample prepared at pH 3.2 reached 1018 m(2)/g. Decreasing pH significantly increased the amount of PEG incorporated into the silica-PEG composites, and hence more pores were generated in the lower pH sample when the PEG was destroyed by calcination at 500°C. The process developed in this study could lead to more efficient conversion of rice husk into high value-added porous materials that might be used for the adsorption of gas and heavy metal ions.

  14. Rice-husk ash paste and concrete: Some aspects of hydration and the microstructure of the interfacial zone between the aggregate and paste

    SciTech Connect

    Zhang, M.H.; Lastra, R.; Malhotra, V.M.

    1996-06-01

    This paper presents an experimental study on the effects of the incorporation of rice-husk ash (RHA) in cement paste and concrete on the hydration and the microstructure of the interfacial zone between the aggregate and paste. The influence on the compressive strength of concrete is discussed, and the results are compared with those obtained with the control portland cement concrete and concrete incorporating silica fume. As for ordinary portland cement paste, it was found that calcium hydroxide and calcium silicate hydrates [C-S-H] were the major hydration and reaction products for the HA paste. Because of the pozzolanic reaction, the paste incorporating RHA had lower Ca(OH){sub 2} content than the control portland cement paste. The incorporation of the RHA in concrete reduced its porosity and the Ca(OH){sub 2} amount in the interfacial zone; the width of the interfacial zone between the aggregate and the cement paste was also reduced compared with the control portland cement composite. However, the porosity in the interfacial zone of the rice-husk ash composite was higher than that of the silica fume composite. The incorporation of the RHA in the cement paste did not increase its compressive strength compared with that of the control. The higher compressive strength of the RHA concrete compared with that of the control is due probably to the reduced porosity, reduced Ca(OH){sub 2}, and reduced width of the interfacial zone between the paste and the aggregate.

  15. One-pot and efficient synthesis of triazolo[1,2-a]indazole-triones via reaction of arylaldehydes with urazole and dimedone catalyzed by silica nanoparticles prepared from rice husk.

    PubMed

    Hamidian, Hooshang; Fozooni, Samieh; Hassankhani, Asadollah; Mohammadi, Sayed Zia

    2011-10-26

    A novel synthesis of triazolo[1,2-a]indazole-1,3,8-trione derivatives by reaction of urazole, dimedone and aromatic aldehydes under conventional heating and microwave irradiation and solvent-free conditions using silica nanoparticles prepared from rice husk ash as catalyst is described. The new method features high yields, multicomponent reactions and environmental friendliness.

  16. Combustion characteristics of husk charcoal

    SciTech Connect

    Shimizu, H.; Kimura, T.; Nishiyama, Y.; Terui, T.

    1984-07-01

    This paper analyzes the factors involved in the extraordinary temperature generation in husk combustion furnaces, and investigates methods of protecting furnaces from heat damage. The combustion characteristics of fixed carbon in rice husks are examined in relation to the air flow rate using different husk charcoals. The theoretical flame temperature in a practical bed was determined from the combustion propagation velocity. It is determined that deviation from the regression line relating the combustion propagation velocity with the specific air flow rate showed a slight correlation with the bulk density of the charcoal samples used.

  17. Utilization of rice husks functionalized with xanthates as cost-effective biosorbents for optimal Cd(II) removal from aqueous solution via response surface methodology.

    PubMed

    Qu, Jianhua; Meng, Xianlin; You, Hong; Ye, Xiuqing; Du, Zhaolin

    2017-10-01

    Pristine rice husk (RH), a kind of agricultural waste based biosorbent, was chemically modified by introducing sulfur-bearing groups with the CS2 treatment under caustic medium. Using response surface methodology (RSM), the interactive effects of three preparation variables on the cadmium uptake and material yield of xanthate-modified rick husk (RH-X) were investigated, and two quadratic regression models were developed to correlate the preparation parameters to the two responses. Through process optimization, the optimal RH-X was finally obtained under the optimum synthesis conditions (i.e., 1.00 CS2-RH ratio, 60.00min xanthation contact time and 18.50°C xanthation temperature), resulting in 138.85mgg(-1) of cadmium uptake, and 68.63% of RH-X yield, strictly similar to the values predicted from the models, with extremely small errors of 0.85 and 0.96%, respectively. Overall, cheap and abundant raw materials, low-cost and easily-controlled preparation and excellent cadmium adsorption ability can make RH-X a preferred biosorbent for wastewater decontamination. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Sonochemical synthesis of silica and silica sulfuric acid nanoparticles from rice husk ash: a new and recyclable catalyst for the acetylation of alcohols and phenols under heterogeneous conditions.

    PubMed

    Salavati-Niasari, Masoud; Javidi, Jaber

    2012-11-01

    Silica nanoparticles were synthesized from rice husk ash at room temperature by sonochemical method. The feeding rate of percipiteting agent and time of sonication were investigated. The nanostructure of the synthesized powder was realized by the FE-SEM photomicrograph, FT-IR spectroscopy, XRD and XRF analyses. These analytical observations have revealed that the nano-sized amorphous silica particles are formed and they are spheroidal in shape. The average particle size of the silica powders is found to be around 50 nm. The as-synthesized silica nanoparticles were subsequently modified with chlorosulfonic acid and prepared silica sulfuric acid nanoparticles, which were employed as an efficient catalyst for the acylation of alcohols and phenols with acetic anhydride in excellent yields under solvent-free conditions at room temperature. This reported method is simple, mild, and environmentally viable and catalyst can be simply recovered and reused over 9 times without any significant loss of its catalytic activity.

  19. Effect of hot vapor filtration on the characterization of bio-oil from rice husks with fast pyrolysis in a fluidized-bed reactor.

    PubMed

    Chen, Tianju; Wu, Ceng; Liu, Ronghou; Fei, Wenting; Liu, Shiyu

    2011-05-01

    To produce high quality bio-oil from biomass using fast pyrolysis, rice husks were pyrolyzed in a 1-5 kg/h bench-scale fluidized-bed reactor. The effect of hot vapor filtration (HVF) was investigated to filter the solid particles and bio-char. The results showed that the total bio-oil yield decreased from 41.7% to 39.5% by weight and the bio-oil had a higher water content, higher pH, and lower alkali metal content when using HVF. One hundred and twelve different chemical compounds were detected by gas chromatography-mass spectrometry (GC-MS). The molecular weight of the chemical compounds from the condenser and the EP when the cyclone was coupled with HVF in the separation system decreased compared with those from the condenser and EP when only cyclone was used.

  20. Effect of sintering temperature on mechanical behaviour and bioactivity of sol-gel synthesized bioglass-ceramics using rice husk ash as a silica source

    NASA Astrophysics Data System (ADS)

    Nayak, J. P.; Bera, J.

    2010-11-01

    Bioglass-ceramics with SiO2-Na2O-CaO composition was prepared by sol-gel method using rice husk ash as a silica source. Material was sintered at different temperatures ranging from 900 to 1050 °C for 2 h. Phase-formation behaviour, densification characteristics, and mechanical strength of glass-ceramics were investigated. The material sintered at 1000 °C showed a good mechanical strength. Mechanical properties were correlated with microstructural features. Both in vitro bioactivity and biodegradability of sintered material were investigated by incubating in simulated body fluid and Tris buffer solution, respectively. Scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction were used to investigate the surface deposition during body fluid incubation. Both bioactivity and degradability decreased with increase in sintering temperature.

  1. Separation of phthalate esters from bio-oil derived from rice husk by a basification-acidification process and column chromatography.

    PubMed

    Zeng, Fanxin; Liu, Wujun; Jiang, Hong; Yu, Han-Qing; Zeng, Raymond J; Guo, Qingxiang

    2011-01-01

    Solid precipitate containing phthalate esters was obtained from rice-husk-derived oil through a basification-acidification process. After separation by column chromatography, the solid precipitate was divided into two mono-component fractions, two bi-component fractions and a tetra-component fraction. The major compounds of the five fractions were all consisted of phthalate esters. Especially, phthalate esters accounted for a proportion higher than 80% in both Fractions I and II. The generation and precipitation mechanisms of phthalate esters were proposed. Phthalate esters were considered to be derived from a series of complicated chemical reactions of small molecules in the biomass pyrolysis process, and precipitated from bio-oil by catalytic hydrolysis and esterification. Copyright © 2010 Elsevier Ltd. All rights reserved.

  2. Selection of metal oxides in the preparation of rice husk ash (RHA)/CaO sorbent for simultaneous SO2 and NO removal.

    PubMed

    Dahlan, Irvan; Lee, Keat Teong; Kamaruddin, Azlina Harun; Mohamed, Abdul Rahman

    2009-07-30

    In this work, the removal of SO(2) and NO from simulated flue gas from combustion process was investigated in a fixed-bed reactor using rice husk ash (RHA)/CaO-based sorbent. Various metal precursors were used in order to select the best metal impregnated over RHA/CaO sorbents. The results showed that RHA/CaO sorbents impregnated with CeO(2) had the highest sorption capacity among other impregnated metal oxides for the simultaneous removal of SO(2) and NO. Infrared spectroscopic results indicated the formation of both sulfate (SO(4)(2-)) and nitrate (NO(3)(-)) species due to the catalytic role played by CeO(2). Apart from that, the catalytic activity of the RHA/CaO/CeO(2) sorbent was found to be closely related to its physical properties (specific surface area, total pore volume and average pore diameter).

  3. Utilization of tin and titanium incorporated rice husk silica nanocomposite as photocatalyst and adsorbent for the removal of methylene blue in aqueous medium

    NASA Astrophysics Data System (ADS)

    Adam, Farook; Appaturi, Jimmy Nelson; Khanam, Zakia; Thankappan, Radhika; Nawi, Mohd. Asri Mohd

    2013-01-01

    A series of tin and titanium incorporated rice husk silica have been synthesized via sol-gel method using cetyltrimethylammonium bromide as the structure directing agent. The samples were labeled as RHA-Silica, RHA-10Sn, RHA-10Ti, and RHA-10Sn10Ti. The BET specific surface areas of these catalysts were found to be 315, 607, 439 and 255 (m2 g-1) with type IV isotherms, respectively. The catalysts were found to be X-ray amorphous and the particle size was found to be in the nano range. Calcination of RHA-10Sn at 500 °C gave silica-tin nanotubes. RHA-10Sn10Ti showed the highest activity in the photocatalytic degradation of methylene blue (MB). The adsorption of MB on these catalysts was found to fit the pseudo-second order kinetic model. The adsorption rate was found to be strongly dependent on the pH of the solution.

  4. Highly enhanced in-field critical current density of MgB 2 superconductor by combined addition of burned rice husk and nano Ho 2O 3

    NASA Astrophysics Data System (ADS)

    Vinod, K.; Varghese, Neson; Sundaresan, A.; Syamaprasad, U.

    2010-04-01

    With the aim of improving flux pinning and in-field critical current density [ JC( H)], two physically and chemically different additives - burned rice husk (BRH) and nano Ho 2O 3 were introduced into in situ MgB 2 superconductor. The effects of the above two additives were studied individually and combinedly. Ho 2O 3 decomposed and reacted with B to form HoB 4, without any substitution. BRH caused considerable amount of C substitution at B site and formed Mg 2Si and Mg 2C 3 secondary phases. Addition of Ho 2O 3 improved the JC( H) only marginally, but BRH improved the JC( H) strongly. Combined addition of Ho 2O 3 with BRH was found to be much more effective than their solo addition for the enhancement of JC( H) of MgB 2.

  5. Dye removal of activated carbons prepared from NaOH-pretreated rice husks by low-temperature solution-processed carbonization and H3PO4 activation.

    PubMed

    Chen, Yun; Zhai, Shang-Ru; Liu, Na; Song, Yu; An, Qing-Da; Song, Xiao-Wei

    2013-09-01

    A coupling of low-temperature sulfuric acid-assisted carbonization and H3PO4 activation was employed to convert NaOH-pretreated rice husks into activated carbons with extremely high surface area (2028 m(2) g(-1)) and integrated characteristics. The influences of the activation temperature and impregnation ratio on the surface area, pore volume of activated carbons were thoroughly investigated. The morphology and surface chemistry of activated carbons were characterized using N2 sorption, FTIR, XPS, SEM, TEM, etc. The adsorption capacity of resulting carbons obtained under optimum preparation conditions was systematically evaluated using methylene blue under various simulated conditions. The adsorption process can be well described by both Langmuir isotherm model and the pseudo-second order kinetics models; and the maximum monolayer capacity of methylene blue was ca. 578 mg g(-1).

  6. Effect of sintering temperature variations on fabrication of 45S5 bioactive glass-ceramics using rice husk as a source for silica.

    PubMed

    Leenakul, Wilaiwan; Tunkasiri, Tawee; Tongsiri, Natee; Pengpat, Kamonpan; Ruangsuriya, Jetsada

    2016-04-01

    45S5 bioactive glass is a highly bioactive substance that has the ability to promote stem cell differentiation into osteoblasts--the cells that create bone matrix. The aim of this work is to analyze physical and mechanical properties of 45S5 bioactive glass fabricated by using rice husk ash as its silica source. The 45S5 bioactive glass was prepared by melting the batch at 1300 °C for 3h. The samples were sintered at different temperatures ranging from 900 to 1050 °C with a fixed dwell-time of 2h. The phase transitions, density, porosity and microhardness values were investigated and reported. DTA analysis was used to examine the crystallization temperatures of the glasses prepared. We found that the sintering temperature had a significant effect on the mechanical and physical properties of the bioactive glass. The XRD showed that when the sintering temperature was above 650 °C, crystallization occurred and bioactive glass-ceramics with Na2Ca2Si3O9, Na2Ca4(PO4)2SiO4 and Ca3Si2O7 were formed. The optimum sintering temperature resulting in maximum mechanical values was around 1050 °C, with a high density of 2.27 g/cm(3), 16.96% porosity and the vicker microhardness value of 364HV. Additionally, in vitro assay was used to examine biological activities in stimulated body fluid (SBF). After incubation in SBF for 7 days, all of the samples showed formations of apatite layers indicating that the 45S5 bioactive glasses using rice husk as a raw material were also bioactive.

  7. Biogenic Hierarchical TiO2/SiO2 Derived from Rice Husk and Enhanced Photocatalytic Properties for Dye Degradation

    PubMed Central

    Yang, Dalong; Fan, Tongxiang; Zhou, Han; Ding, Jian; Zhang, Di

    2011-01-01

    Background Rice husk, an agricultural bioresource, is utilized as a non-metallic bio-precursor to synthesize biogenic hierarchical TiO2/SiO2 (BH-TiO2/SiO2) and the products are applied to dye degradation. Methodology/Principal Findings The as-prepared BH-TiO2/SiO2 samples are characterized by X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), nitrogen-adsorption measurement, UV-vis spectroscopy and electronic paramagnetic resonance (EPR). The results show that BH-TiO2/SiO2 possesses both anatase and rutile phases with amorphous SiO2 as background, which contains mesopore structure, and nitrogen derived from original rice husk is self-doped into the lattice. Besides, the light-harvesting within the visible-light range of BH-TiO2/SiO2 has been enhanced. Moreover, the catalytic activity of BH-TiO2/SiO2 has been proven by EPR, and both the photocatalytic activity and stability of BH-TiO2/SiO2 are improved as well, which has been illustrated by cycled degradation of methylene blue dye under irradiation. Conclusions/Significance This work provides a good way to combine natural hierarchical porous structure with synthetic material chemistry based on available biomass in the vast natural environment for the sustainable development of human society, and extends potentials of biomass in applications such as photocatalysts, sunlight splitting water and so forth. PMID:21931853

  8. Effects of production conditions on yield and physicochemical properties of biochars produced from rice husk and oil palm empty fruit bunches.

    PubMed

    Yavari, Saba; Malakahmad, Amirhossein; Sapari, Nasiman B

    2016-09-01

    Biochar is the bio-solid material produced by pyrolysis. The biochar properties are controlled by feedstock and pyrolysis variables. In this study, the impacts of these production variables on biochar yield and physicochemical properties including pH, cation exchange capacity (CEC), total organic carbon (TOC) content, surface area, and pore volume and size were investigated. Rice husk (RH) and oil palm empty fruit bunches (EFB) were used as biomass. The biochars were produced at temperature range of 300 to 700 °C, heating rate of 3 to 10 °C/min and retention time of 1 to 3 h. The pyrolysis conditions were optimized using response surface methodology (RSM) technique to maximize the values of the responses. Analysis of variance (ANOVA) of the results demonstrated that the data fitted well to the linear and quadratic equations. Temperature was found to be the most effective parameter on the responses followed by retention time and heating rate, sequentially. CEC, TOC, surface area, and pore characteristics were evaluated as biochar properties determining their sorption potential. The optimum conditions for the maximum values of the properties were temperatures of 700 and 493.44 °C and time of 3 and 1 h for RH and EFB biochars, respectively. Heating rate at 3 °C/min was found to be the best rate for both biochars. The structure of EFB biomass was more sensitive to heating than rice husk. The biomass type and the production variables were demonstrated as the direct effective factors on biochar yield and physicochemical properties.

  9. Determination and Uncertainty Analysis of Inorganic Arsenic in Husked Rice by Solid Phase Extraction and Atomic Absorption Spectrometry with Hydride Generation.

    PubMed

    Saxena, Sushil Kumar; Karipalli, Agnes Raju; Krishnan, Anoop A; Rangasamy, Rajesh; Malekadi, Praveen; Singh, Dhirendra P; Vasu, Vimesh; Singh, Vijay K

    2017-05-01

    This study enables the selective determination of inorganic arsenic (iAs) with a low detection limit using an economical instrument [atomic absorption spectrometer with hydride generation (HG)] to meet the regulatory requirements as per European Commission (EC) and Codex guidelines. Dry rice samples (0.5 g) were diluted using 0.1 M HNO3-3% H2O2 and heated in a water bath (90 ± 2°C) for 60 min. Through this process, all the iAs is solubilized and oxidized to arsenate [As(V)]. The centrifuged extract was loaded onto a preconditioned and equilibrated strong anion-exchange SPE column (silica-based Strata SAX 500 mg/6 mL), followed by selective and sequential elution of As(V), enabling the selective quantification of iAs using atomic absorption spectrometry with HG. In-house validation showed a mean recovery of 94% and an LOQ of 0.025 mg/kg. The repeatability (HorRatr) and reproducibility (HorRatR) values were <2, meeting the performance criteria mandated by the EC. The combined standard measurement uncertainty by this method was less than the maximum standard measurement uncertainty; thus, the method can be considered for official control purposes. The method was applied for the determination of iAs in husked rice samples and has potential applications in other food commodities.

  10. Synthesis and characterisation of composite based biohydroxyapatite bovine bone mandible waste (BHAp) doped with 10 wt % amorphous SiO{sub 2} from rice husk by solid state reaction

    SciTech Connect

    Asmi, Dwi E-mail: dwi.asmi@fmipa.unila.ac.id; Sulaiman, Ahmad Oktavia, Irene Lucky; Badaruddin, Muhammad; Zulfia, Anne

    2016-04-19

    Effect of 10 wt% amorphous SiO{sub 2} from rice husk addition on the microstructures of biohydroxyapatite (BHAp) obtained from bovine bone was synthesized by solid state reaction. In this study, biohydroxyapatite powder was obtained from bovine bone mandible waste heat treated at 800 °C for 5 h and amorphous SiO{sub 2} powder was extracted from citric acid leaching of rice husk followed by combustion at 700°C for 5 h. The composite powder then mixed and sintered at 1200 °C for 3 h. X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy and Scanning electron microscopy (SEM) techniques are utilized to characterize the phase relations, functional group present and morphology of the sample. The study has revealed that the processing procedures played an important role in microstructural development of BHAp-10 wt% SiO{sub 2} composite. The XRD study of the raw material revealed that the primary phase material in the heat treated of bovine bone mandible waste is hydroxyapatite and in the combustion of rice husk is amorphous SiO{sub 2}. However, in the composite the hydroxyapatite, β-tricalcium phosphate, and calcium phosphate silicate were observed. The FTIR result show that the hydroxyl stretching band in the composite decrease compared with those of hydroxyapatite spectra and the evolution of morphology was occurred in the composite.

  11. Rice husk based porous carbon loaded with silver nanoparticles by a simple and cost-effective approach and their antibacterial activity.

    PubMed

    Cui, Jianghu; Yang, Yunhua; Hu, Yonghui; Li, Fangbai

    2015-10-01

    In this paper, we chose rice husk as raw material and synthesized successfully porous carbon loaded with silver nanoparticles (RH-Ag) composites by simple and cost-effective method. The as-prepared RH-Ag composites have a BET-specific surface area of 1996 m(2) g(-1) and result in strong capacity of bacteria adsorption. The result of antibacterial study indicated that the RH-Ag system displayed antibacterial activity that was two times better than pure Ag NPs. Our study demonstrates that the antibacterial activity of RH-Ag composites may be attributed to their strong adsorption ability with bacteria and result in the disorganization of the bacterial membrane ultrastructure. In addition, RH-Ag system was found to be durative slow-releasing of silver ions and biocompatible for human skin keratinocytes cells. In terms of these advantages, the RH-Ag composites have potential application in antibacterial infections and therapy. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Pressurized pyrolysis of rice husk in an inert gas sweeping fixed-bed reactor with a focus on bio-oil deoxygenation.

    PubMed

    Qian, Yangyang; Zhang, Jie; Wang, Jie

    2014-12-01

    The pyrolysis of rice husk was conducted in a fixed-bed reactor with a sweeping nitrogen gas to investigate the effects of pressure on the pyrolytic behaviors. The release rates of main gases during the pyrolysis, the distributions of four products (char, bio-oil, water and gas), the elemental compositions of char, bio-oil and gas, and the typical compounds in bio-oil were determined. It was found that the elevation of pressure from 0.1MPa to 5.0MPa facilitated the dehydration and decarboxylation of bio-oil, and the bio-oils obtained under the elevated pressures had significantly less oxygen and higher calorific value than those obtained under atmospheric pressure. The former bio-oils embraced more acetic acid, phenols and guaiacols. The elevation of pressure increased the formation of CH4 partially via the gas-phase reactions. An attempt is made in this study to clarify "the pure pressure effect" and "the combined effect with residence time". Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Extraction of nano-silicon with activated carbons simultaneously from rice husk and their synergistic catalytic effect in counter electrodes of dye-sensitized solar cells

    PubMed Central

    Ahmad, Waqar; bahrani, Majid Raissan Al; Yang, Zhichun; Khan, Jahangeer; Jing, Wenkui; Jiang, Fan; Chu, Liang; Liu, Nishuang; Li, Luying; Gao, Yihua

    2016-01-01

    The extraction of renewable energy resources particularly from earth abundant materials has always been a matter of significance in industrial products. Herein, we report a novel simultaneous extraction of nano-silicon with activated carbons (nano-Si@ACs) from rice husk (RH) by chemical activation method. As-extracted nano-Si@ACs is then used as an energy harvesting materials in counter electrodes (CEs) of dye-sensitized solar cells (DSSCs). The morphology, structure and texture studies confirm the high surface area, abundant active sites and porous structure of nano-Si@ACs. Electrochemical impedance spectroscopy and cyclic voltammetry analyses reveal that the nano-Si@ACs is highly beneficial for fast I3− reduction and superior electrolyte diffusion capability. The nano-Si@ACs CE based DSSC exhibits enhanced power conversion efficiency of (8.01%) in contrast to pristine Pt CE (7.20%). These favorable results highlight the potential application of RH in low-cost, high-efficiency and Pt-free DSSCs. PMID:28000720

  14. Preparation and characterization activated carbon from rice husk and oil palm empty fruit bunches for removal of Zn2+ in aqueous solution

    NASA Astrophysics Data System (ADS)

    Ismail, Nur Enzati Afwana; Taha, Mohd F.; Ramli, Anita

    2016-11-01

    The ability of activated carbon prepared from rice husk (RH), oil palm empty fruit bunches (EFB) and mixture (Mix) activated carbon in adsorption of Zinc (Zn2+) from aqueous solution was investigated. The Mix activated carbon has prepared from mixture of RH and EFB activated carbon with weight ratio (1:1) The RH and EFB activated carbon were produced by using sodium hydroxide (NaOH) as a dehydrating agent in chemical activation process.EFB activated carbon showed excellent efficiency in removing Zn2+ with their percentage removal up to 100% even at low adsorbent dosage. The study also showed that the adsorption of Zn2+ by EFB, RH and Mix activated carbon is dependent on the adsorbent dosage and initial metal concentration. The adsorption isotherms of the Zn2+ of EFB, RH and Mix activated carbon were determined and compared with Langmuir and Freundlich models. It was showed that Langmuir model was more favorable for RH and Mix activated carbon with correlation coefficient (R2) value is 0.9958 and 0.9847. In contrast, EFB activated carbon was more favorable to the Freundlich and Langmuir model with correlation coefficient (R2) are 0.9967 and 0.9967

  15. Extraction of nano-silicon with activated carbons simultaneously from rice husk and their synergistic catalytic effect in counter electrodes of dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Ahmad, Waqar; Bahrani, Majid Raissan Al; Yang, Zhichun; Khan, Jahangeer; Jing, Wenkui; Jiang, Fan; Chu, Liang; Liu, Nishuang; Li, Luying; Gao, Yihua

    2016-12-01

    The extraction of renewable energy resources particularly from earth abundant materials has always been a matter of significance in industrial products. Herein, we report a novel simultaneous extraction of nano-silicon with activated carbons (nano-Si@ACs) from rice husk (RH) by chemical activation method. As-extracted nano-Si@ACs is then used as an energy harvesting materials in counter electrodes (CEs) of dye-sensitized solar cells (DSSCs). The morphology, structure and texture studies confirm the high surface area, abundant active sites and porous structure of nano-Si@ACs. Electrochemical impedance spectroscopy and cyclic voltammetry analyses reveal that the nano-Si@ACs is highly beneficial for fast I3- reduction and superior electrolyte diffusion capability. The nano-Si@ACs CE based DSSC exhibits enhanced power conversion efficiency of (8.01%) in contrast to pristine Pt CE (7.20%). These favorable results highlight the potential application of RH in low-cost, high-efficiency and Pt-free DSSCs.

  16. Suppressive components in rice husk against mutagens-induced SOS response using Salmonella typhimurium TA1535/pSK1002 umu test.

    PubMed

    Okuno, Yoshiharu; Miyazawa, Mitsuo

    2007-07-20

    The EtOAc extract from rice (Oriza sativa cv. Hinohikari) husk showed a suppressive effect on umu gene expression of the SOS response in Salmonella typhimurium TA1535/pSK1002 against the mutagen, Trp-P-1, which requires liver metabolizing enzyme. To obtain the suppressive compound, the EtOAc extract was fractionated by SiO(2) column chromatography using umu test as a bioassay guide. Suppressive compound was isolated and identified as momilactone A (1) by EIMS, IR, (1)H- and (13)C-NMR spectroscopy. Compound 1 inhibited of the SOS-inducing activity of Trp-P-1 in the umu test. Gene expression was suppressed by 32.6% at less than 0.60 mM. Compound 1 was assayed with activated Trp-P-1. The suppressive effect of Compound 1 was decreased compared with that of Trp-P-1. Furthermore, 1 was assayed with another mutagens, such as MeIQ, activated MeIQ, furylfuramide (AF-2), MNNG, and UV-irradiation. Compound 1 showed greater suppressive effect on AF-2-inducing SOS response than other mutagens.

  17. Adsorption of Pb(II) using silica gel composite from rice husk ash modified 3-aminopropyltriethoxysilane (APTES)-activated carbon from coconut shell

    NASA Astrophysics Data System (ADS)

    Yusmaniar, Purwanto, Agung; Putri, Elfriyana Awalita; Rosyidah, Dzakiyyatur

    2017-03-01

    Silica gel modified by 3-aminopropyltriethoxysilane (APTES) was synthesized from rice husk ash combined with activated carbon from coconut shell yielded the composite adsorbent. The composite was characterized by Fourier Transform Infra Red spectroscopy (FT-IR), Electron Dispersive X-Ray (EDX), Surface Area Analyzer (SAA) and adsorption test by Atomic Absorption Spectrometry (AAS). This composite adsorbent has been used moderately for the removal of lead ions from metal solutions and compared with silica gel modified APTES and activated carbon. The adsorption experiments of Pb -ions by adsorbents were performed at different pH and contact time with the same metal solutions concentration, volume solution, and adsorbent dosage. The optimum pH for the adsorption was found to be 5.0 and the equilibrium was achieved for Pb with 20 min of contact time. Pb ions adsorption by composite silica gel modified APTES-activated carbon followed by Langmuir isotherm model with qmax value of 46.9483 mg/g that proved an adsorbent mechanism consistent to the mechanism of monolayer formation.

  18. Utilization of rice husk ash as silica source for the synthesis of mesoporous silicas and their application to CO2 adsorption through TREN/TEPA grafting.

    PubMed

    Bhagiyalakshmi, Margandan; Yun, Lee Ji; Anuradha, Ramani; Jang, Hyun Tae

    2010-03-15

    Mesoporous MCM-41, MCM-48 and SBA-15 were synthesized using Rice husk ash (RHA) as the silica source and their defective Si-OH sites were functionalized by 3-chloropropyltrimethoxysilane (CPTMS) which was subsequently grafted with amine compounds, Tris(2-aminoethyl)amine (TREN) and Tetraethylenepentamine (TEPA). X-ray powder diffraction (XRD) and BET results of the parent mesoporous silica suggested their closeness of structural properties to those obtained from conventional silica sources. CO(2) adsorption of branched amine TREN and straight chain amine TEPA at 25, 50 and 75 degrees C was obtained by Thermogravimetric Analyser (TGA) at atmospheric pressure. TREN grafted mesoporous silica showed 7% of CO(2) adsorption while TEPA grafted mesoporous silicas showed less CO(2) adsorption, which is due to the presence of isolated amine groups in TREN. TREN grafted mesoporous silicas were also observed to be selective towards CO(2), thermally stable and recyclable. The order of CO(2) adsorption with respect to amount of amine grafting was observed to be MCM-48/TREN>MCM-41/TREN>SBA-15/TREN.

  19. In situ generation of a hydroxyl radical by nanoporous activated carbon derived from rice husk for environmental applications: kinetic and thermodynamic constants.

    PubMed

    Karthikeyan, S; Sekaran, G

    2014-03-07

    The objective of this investigation is to evaluate the hydroxyl radical (˙OH) generation using nanoporous activated carbon (NPAC), derived from rice husk, and dissolved oxygen in water. The in situ production of the ˙OH radical was confirmed through the DMPO spin trapping method in EPR spectroscopy and quantitative determination by a deoxyribose assay procedure. NPAC served as a heterogeneous catalyst to degrade 2-deoxy-d-ribose (a reference compound) using hydroxyl radical generated from dissolved oxygen in water at temperatures in the range 313-373 K and pH 6, with first order rate constants (k = 9.2 × 10(-2) min(-1), k = 1.2 × 10(-1) min(-1), k = 1.3 × 10(-1) min(-1) and k = 1.68 × 10(-1) min(-1)). The thermodynamic constants for the generation of hydroxyl radicals by NPAC and dissolved oxygen in water were ΔG -1.36 kJ mol(-1) at 313 K, ΔH 17.73 kJ mol(-1) and ΔS 61.01 J mol(-1) K(-1).

  20. Analysis of SO2 sorption capacity of rice husk ash (RHA)/CaO/NaOH sorbents using response surface methodology (RSM): untreated and pretreated RHA.

    PubMed

    Dahlan, Irvan; Lee, Keat Teong; Kamaruddin, Azlina Harun; Mohamed, Abdul Rahman

    2008-03-01

    The SO2 sorption capacity (SSC) of sorbents prepared from rice husk ash (RHA) with NaOH as additive was studied in a fixed-bed reactor. The sorbents were prepared using a water hydration method by slurrying RHA, CaO, and NaOH. Response surface methodology (RSM) based on four-variable central composite face centered design (CCFCD) was employed in the synthesis of the sorbents. The correlation between the sorbent SSC (as response) with four independent sorbent preparation variables, i.e. hydration period, RHA/CaO ratio, NaOH amount, and drying temperature, were presented as empirical mathematical models. Among all the variables studied, the amount of NaOH used was found to be the most significant variable affecting the SSC of the sorbents prepared. The SSC for sorbent prepared with the addition of NaOH was found to be significantly higher than sorbents prepared without NaOH. This is probably because NaOH is a deliquescent material, and its existence increases the amount of water collected on the surface of the sorbent, a condition required for sorbent-SO2 reaction to occur at low temperature. The effect of further treatment of RHA at 600 degrees C was also investigated. Although pretreated RHA sorbents demonstrated higher SSC as compared to untreated RHA sorbents, nevertheless, at optimum conditions, sorbents prepared from untreated RHA was found to be more favorable due to practical and economic concerns.

  1. Evaluation of various additives on the preparation of rice husk ash (RHA)/CaO-based sorbent for flue gas desulfurization (FGD) at low temperature.

    PubMed

    Dahlan, Irvan; Lee, Keat Teong; Kamaruddin, Azlina Harun; Mohamed, Abdul Rahman

    2009-01-15

    This paper examines the effectiveness of 10 additives toward improving SO2 sorption capacities (SSC) of rice husk ash (RHA)/lime (CaO) sorbent. The additives examined are NaOH, CaCl2, LiCl, NaHCO3, NaBr, BaCl2, KOH, K2HPO4, FeCl3 and MgCl2. Most of the additives tested increased the SSC of RHA/CaO sorbent, whereby NaOH gave highest SSC (30mg SO2/g sorbent) at optimum concentration (0.25mol/l) compared to other additives examined. The SSC of RHA/CaO sorbent prepared with NaOH addition was also increases from 17.2 to 39.5mg SO2/g sorbent as the water vapor increases from 0% RH to 80% RH. This is probably due to the fact that most of additives tested act as deliquescent material, and its existence increases the amount of water collected on the surface of the sorbent, which played an important role in the reaction between the dry-type sorbent and SO2. Although most of the additives were shown to have positive effect on the SSC of the RHA/CaO sorbent, some were found to have negative or insignificant effect. Thus, this study demonstrates that proper selection of additives can improve the SSC of RHA/CaO sorbent significantly.

  2. The integrated production of microbial lipids and bio-SiO2 from rice husks by an organic electrolytes pretreatment technology.

    PubMed

    Yu, Xue; Tian, Jing; Xie, Haibo; Shen, Hongwei; Wang, Qian

    2014-02-01

    In this study, a full dissolution behavior of rice husks (RHs) in ionic liquids-based organic electrolytes was achieved, and physicochemical effect of the dissolution pretreatment on the structures of RHs was elucidated. The physicochemical changes led to an enhanced subsequent enzymatic saccharification of RHs, and a total reducing sugars (TRSs) yield of 0.70gg(-1), and a glucose yield of 0.43gg(-1) were obtained. The hydrolysates could be used as carbon sources for the cultivation of Rhodosporidium toruloides Y4 for the production of microbial lipids with a satisfactory productivity of cell biomass (13.3gL(-1)) and lipid content (32.5%) after 100h cultivation. Further pyrolysis of the residuals after the enzymatic hydrolysis at 600°C for 3h resulted in new uniform, spherical silica powder materials with particle size around 150nm, and surface area of 179.3m(2)g(-1). Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Characterization of platinum-iron catalysts supported on MCM-41 synthesized with rice husk silica and their performance for phenol hydroxylation

    NASA Astrophysics Data System (ADS)

    Chumee, Jitlada; Grisdanurak, Nurak; Neramittagapong, Arthit; Wittayakun, Jatuporn

    2009-01-01

    Mesoporous material RH-MCM-41 was synthesized with rice husk silica by a hydrothermal method. It was used as a support for bimetallic platinum-iron catalysts Pt-Fe/RH-MCM-41 for phenol hydroxylation. The catalysts were prepared by co-impregnation with Pt and Fe at amounts of 0.5 and 5.0 wt.%, respectively. The RH-MCM-41 structure in the catalysts was studied with x-ray diffraction, and their surface areas were determined by nitrogen adsorption. The oxidation number of Fe supported on RH-MCM-41 was + 3, as determined by x-ray absorption near edge structure (XANES) analysis. Transmission electron microscopy (TEM) images of all the catalysts displayed well-ordered structures, and metal nanoparticles were observed in some catalysts. All the catalysts were active for phenol hydroxylation using H2O2 as the oxidant at phenol : H2O2 mole ratios of 2 : 1, 2 : 2, 2 : 3 and 2 : 4. The first three ratios produced only catechol and hydroquinone, whereas the 2 : 4 ratio also produced benzoquinone. The 2 : 3 ratio gave the highest phenol conversion of 47% at 70 °C. The catalyst prepared by co-impregnation with Pt and Fe was more active than that prepared using a physical mixture of Pt/RH-MCM-41 and Fe/RH-MCM-41.

  4. Magnetic Phase Development of Iron Oxide-SiO{sub 2} Aerogel and Xerogel Prepared using Rice Husk Ash as Precursor

    SciTech Connect

    Maamur, K. N.; Jais, U. S.; Yahya, S. Y. S.

    2010-03-11

    This study is aimed to produce iron incorporated silica aerogel and xerogel from rice husk ash. Two sol--gel chemistry routes have been used to synthesize both samples. Iron in the form of hydrated iron nitrate with compositions in the range of 3-17 wt%(Fe{sub 2}O{sub 3}/Fe{sub 2}O{sub 3}+SiO{sub 2}) were used as iron source. For aerogel samples, iron was added at the solution level whereas for xerogel samples, iron was added after the gelation. The synthesis of iron doped aerogel was done by supercritical drying at temperature about 250 deg. C and pressure of about 5.9 MPa (850 psi) while xerogel was formed by drying the aquagel in an oven at 110 deg. C for 24 hours. The iron doped aerogel and xerogel composites were further heated to various temperatures to obtain the magnetic phase. Results show that the only sample that signifies the presence of maghemite (gamma-Fe{sub 2}O{sub 3}) is the aerogel sample doped with 7.3 wt% iron at temperature 1100 deg. C while other samples show the presence of magnetite.

  5. Study on the effects of white rice husk ash and fibrous materials additions on some properties of fiber-cement composites.

    PubMed

    Hamzeh, Yahya; Ziabari, Kamran Pourhooshyar; Torkaman, Javad; Ashori, Alireza; Jafari, Mohammad

    2013-03-15

    This work assesses the effects of white rice husk ash (WRHA) as pozzolanic material, virgin kraft pulp (VKP), old corrugated container (OCC) and fibers derived from fiberboard (FFB) as reinforcing agents on some properties of blended cement composites. In the sample preparation, composites were manufactured using fiber-to-cement ratio of 25:75 by weight and 5% CaCl(2) as accelerator. Type II Portland cement was replaced by WRHA at 0%, 25% and 50% by weight of binder. A water-to-binder ratio of 0.55 was used for all blended cement paste mixes. For parametric study, compressive strength, water absorption and density of the composite samples were evaluated. Results showed that WRHA can be applied as a pozzolanic material to cement and also improved resistance to water absorption. However, increasing the replacement level of WRHA tends to reduce the compressive strength due to the low binding ability. The optimum replacement level of WRHA in mortar was 25% by weight of binder; this replacement percentage resulted in better compressive strengths and water absorption. OCC fiber is shown to be superior to VKF and FFB fibers in increasing the compressive strength, due to its superior strength properties. As expected, the increase of the WRHA content induced the reduction of bulk density of the cement composites. Statistical analysis showed that the interaction of above-mentioned variable parameters was significant on the mechanical and physical properties at 1% confidence level.

  6. Sorption of SO(2) and NO from simulated flue gas over rice husk ash (RHA)/CaO/CeO(2) sorbent: evaluation of deactivation kinetic parameters.

    PubMed

    Dahlan, Irvan; Lee, Keat Teong; Kamaruddin, Azlina Harun; Mohamed, Abdul Rahman

    2011-01-30

    In this study, the kinetic parameters of rice husk ash (RHA)/CaO/CeO(2) sorbent for SO(2) and NO sorptions were investigated in a laboratory-scale stainless steel fixed-bed reactor. Data experiments were obtained from our previous results and additional independent experiments were carried out at different conditions. The initial sorption rate constant (k(0)) and deactivation rate constant (k(d)) for SO(2)/NO sorptions were obtained from the nonlinear regression analysis of the experimental breakthrough data using deactivation kinetic model. Both the initial sorption rate constants and deactivation rate constants increased with increasing temperature, except at operating temperature of 170 °C. The activation energy and frequency factor for the SO(2) sorption were found to be 18.0 kJ/mol and 7.37 × 10(5)cm(3)/(g min), respectively. Whereas the activation energy and frequency factor for the NO sorption, were estimated to be 5.64 kJ/mol and 2.19 × 10(4)cm(3)/(g min), respectively. The deactivation kinetic model was found to give a very good agreement with the experimental data of the SO(2)/NO sorptions.

  7. Microsized Porous SiOx@C Composites Synthesized through Aluminothermic Reduction from Rice Husks and Used as Anode for Lithium-Ion Batteries.

    PubMed

    Cui, Jinlong; Cui, Yongfu; Li, Shaohui; Sun, Hongliang; Wen, Zhongsheng; Sun, Juncai

    2016-11-09

    Microsized porous SiOx@C composites used as anode for lithium-ion batteries (LIBs) are synthesized from rice husks (RHs) through low-temperature (700 °C) aluminothermic reduction. The resulting SiOx@C composite shows mesoporous irregular particle morphology with a high specific surface area of 597.06 m(2)/g under the optimized reduction time. This porous SiOx@C composite is constructed by SiOx nanoparticles uniformly dispersed in the C matrix. When tested as anode material for LIBs, it displays considerable specific capacity (1230 mAh/g at a current density of 0.1 A/g) and excellent cyclic stability with capacity fading of less than 0.5% after 200 cycles at 0.8 A/g. The dramatic volume change for the Si anode during lithium-ion (Li(+)) insertion and extraction can be successfully buffered because of the formation of Li2O and Li4SiO4 during initial lithiation process and carbon coating layer on the surface of SiOx. The porous structure could also mitigate the volume change and mechanical strains and shorten the Li(+) diffusion path length. These characteristics improve the cyclic stability of the electrode. This low-cost and environment-friendly SiOx@C composite anode material exhibits great potential as an alternative for traditional graphite anodes.

  8. Remediation of a Cr (VI) contaminated soil : Soil washing followed by Cr (VI) reduction using a sorbent prepared from rice husk

    NASA Astrophysics Data System (ADS)

    El-Shafey, E. L.; Canepa, P.

    2003-05-01

    A Cr (VI) contaminated soil with concentrations up to 16.000 ppm was washed with 0.1M citric, 0.1M acetic, 0.1M HCI, 0.1M sulphuric acid, 0.1M NaOH and hot distiUed water. Soil characterisation including pH, metal content and cation exchange capacity was canied out since the soil was highly basic (pH 11.6), hot water was found to be most effective for soil washing. Rice husk was used to prepare a carbonaeeous sorbent using sulphuric acid treatment. The removal kinetics of Cr (VI) from aqueous solutions was investigated at different temperature, pH, metal ion concentration and sorbent status (wet and dry). The rate of Cr (VI) reduction at low pH values followed a first order rate expression approaching equilibrium within 50 hours for wet sorbent and 70 hours for the one which was previously dried. The soil leachate was acidifie to pHleq 2 and reduced to Cr (III) using the carbonaceous sorbent. The carbonaceous sorbent seems cheap and efficient for Cr (VI) removal.

  9. Comparison of rice husk- and dairy manure-derived biochars for simultaneously removing heavy metals from aqueous solutions: role of mineral components in biochars.

    PubMed

    Xu, Xiaoyun; Cao, Xinde; Zhao, Ling

    2013-08-01

    Rice husk biochar (RHBC) and dairy manure biochar (DMBC) were prepared as sorbents for simultaneously removing Pb, Cu, Zn, and Cd from aqueous solutions. DMBC was more effective in removing all the four heavy metals than RHBC, with the removal capacities of above 486 mmol kg(-1) for each metal, much higher than those of RHBC (65.5-140 mmol kg(-1)). RHBC showed stronger competition for metal removal than DMBC when the four metals coexisted, with Pb the least affected and Cd the most inhibited. When each metal was 1mM in the multi-metal system, the metal removal by RHBC was reduced by 38.4-100%, much higher than that reduced by 2-40.9% for DMBC. The stronger competition for metals removal by RHBC was due to the fact that all metals competed only for the ionized phenolic-O(-) groups, while the removal of metals by DMBC resulted not only from the complexation with ionized hydroxyl-O(-) groups but also from the precipitation of metals with CO3(2-) and/or PO4(3-) that were rich in DMBC, resulting in less competition. The different mechanisms for the removal of metals by the two biochars were evidenced by the instrumental analysis of XRD, FTIR, and SEM as well as chemical modeling of Visual MINTEQ. Results indicated the waste biomass can be converted into value-added biochar as sorbents for removal of heavy metals and the removal ability varies with different biochar feedstock sources where the mineral components such as CO3(2-), PO4(3-) originated from the feedstock play an important role in the sorption nature of biochar.

  10. Effect of MnO2 doped on physical, structure and optical properties of zinc silicate glasses from waste rice husk ash

    NASA Astrophysics Data System (ADS)

    Al-Nidawi, Ali Jabbar Abed; Matori, Khamirul Amin; Zakaria, Azmi; Mohd Zaid, Mohd Hafiz

    In this study, an investigation was conducted to explore and synthesize silicate (SiO2) glass from waste rice husk ash (RHA). MnO2 doped zinc silicate glasses with chemical formula [(ZnO)55 + (WRHA)45]100-X[MnO2]X, (where X = 0, 1, 3 and 5 wt%) was prepared by conventional melt quenching technique. The glass samples were characterized using energy dispersive X-ray fluorescence (EDXRF), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR) spectroscopy, and ultraviolet-visible (UV-Vis) spectroscopy. The results revealed that by increasing the concentration of MnO2, the color of glass samples changed from colorless to brown and the density of glass increased. XRD results showed that a broad halo peak which centered on the low angle (2θ = 30°) indicated the amorphous nature of the glass. FTIR results showed basic structural units of Si-O-Si in non-bridging oxygen, Si-O and Mn-O in the glass network. FESEM result showed a decreasing porosity with an increasing MnO2 content, which was attributed to the Mn ions resort to occupy interstitial sites inside the pores of glass. Besides, the absorption intensity of glass increased and the band gap value decreased with increasing the MnO2 percentage. In this synthesized glass system of MnO2 doped zinc silicate glasses using RHA as a source of silica, the MnO2 affect most of the properties of the glass system under investigation.

  11. Comparative study on the mobility and speciation of heavy metals in ashes from co-combustion of sewage sludge/dredged sludge and rice husk.

    PubMed

    Wang, Teng; Xue, Yongjie; Zhou, Min; Yuan, Yunjuan; Zhao, Suyun; Tan, Gang; Zhou, Xian; Geng, Junjun; Wu, Shaopeng; Hou, Haobo

    2017-02-01

    The co-combustion of sludge (sewage and dredged sludge) with rice husk is expected to become a trend because of its economic and environmental benefits. However, the massive residues from the co-combustion process and the mobility of heavy metals (HMs) warrant special attention. The basic performance and environmental properties of the trace elements (Cr, Cu, Fe, Mn, Ba and Zn) from the co-combustion ashes were studied to promote the further utilization of these materials. These ashes have a shell particle shape, high specific area, high amorphous content and low crystalline phase content. The investigation mainly focused on the environmental properties of these ashes to evaluate the risk of these by-products to the environment. Results show Cu, Mn, and Zn have cumulative leaching concentrations of 1.033, 23.32, and 3.363 mg/L for W, by contrast, Cr, Cu, Fe, Mn, Ba, and Zn have cumulative leaching concentrations of 0.488, 0.296, 8.069, 10.44, 2.568, and 2.691 mg/L for H, which are much greater than the Chinese ground water standard (GB/T14848-93). Meanwhile Mn, Zn, Ba, Cr, and Fe all pose a very high risk for H, while Cu only poses a medium risk, and all HMs in W exhibit much lower contamination levels than those in H by the method of risk assessment code (RAC). It indicates that these ashes have undesirably high levels of HMs that demonstrate high mobility and pose environmental risks according to their leachability and chemical speciation. And the HMs in W show lower mobility and environmental hazards than those in H.

  12. Response surface optimization of a dynamic dye adsorption process: a case study of crystal violet adsorption onto NaOH-modified rice husk.

    PubMed

    Chowdhury, Shamik; Chakraborty, Sagnik; Saha, Papita Das

    2013-03-01

    The adsorption of crystal violet from aqueous solution by NaOH-modified rice husk was investigated in a laboratory-scale fixed-bed column. A two-level three factor (2(3)) full factorial central composite design with the help of Design Expert Version 7.1.6 (Stat Ease, USA) was used for optimisation of the dynamic dye adsorption process and evaluation of interaction effects of different operating parameters: initial dye concentration (100-200 mg L(-1)), flow rate (10-30 mL min(-1)) and bed height (5-25 cm). A correlation coefficient (R (2)) value of 0.999, model F value of 1,936.59 and its low p value (<0.0001) along with lower value of coefficient of variation (1.38 %) indicated the fitness of the response surface quadratic model developed during the present study. Numerical optimisation applying desirability function was used to identify the optimum conditions for a targeted breakthrough time of 12 h. The optimum conditions were found to be initial solution pH=8.00, initial dye concentration=100 mg L(-1), flow rate=22.88 mL min(-1) and bed height=18.75 cm. A confirmatory experiment was performed to evaluate the accuracy of the optimised procedure. Under the optimised conditions, breakthrough appeared after 12.2 h and the column efficiency was determined as 99 %. The Thomas model showed excellent fit to the dynamic dye adsorption data obtained from the confirmatory experiment. Thereby, it was concluded that the current investigation gives valuable insights for designing and establishing a continuous wastewater treatment plant.

  13. Synthesis of magMCM-41 with rice husk silica as cadmium sorbent from aqueous solutions: parameters' optimization by response surface methodology.

    PubMed

    Kamari, Soran; Ghorbani, Farshid

    2016-10-06

    The magnetic mesoporous silica of magMCM-41 with large surface area (695 m(2) g(-1)) and high magnetization (10.79 emu g(-1)) was synthesized using extracted amorphous silica from rice husk. The synthesized materials were applied for adsorption of Cd(II) ions from aqueous solution in batch operation systems. A highly selective adsorbent was obtained by grafting 3-aminopropyltrimethoxysilane on the pores of the magMCM-41 in which the adsorption capacity of Cd(II) ions increased from 41.8 to 86 mg g(-1), under the same conditions. A total of 20 sets of experiments were planned by the central composite design under response surface methodology. The effects of three independent variables pH, initial Cd(II) ion concentration and sorbent dosage were investigated on the adsorption capacity (qe) and removal efficiency (R) of cadmium. The best responses for Cd(II) adsorption capacity and removal efficiency were 493.21 mg g(-1) and 60.25%, respectively, which was achieved at pH of 5.05, sorbent dosage of 0.1 g L(-1) and Cd(II) concentration of 150 mg L(-1). Additionally, the obtained value for desirability was equal to 0.807. The theoretical isotherm models were applied to describe the adsorption process that the Langmuir model provides the best correlation of the equilibrium data. The kinetics study revealed that data from the experiments fitted well to the pseudo-second-order equation than the pseudo-first-order equation. The thermodynamic parameters revealed that the adsorption process strongly depended on temperature and indicated the exothermic behavior and spontaneous nature of the adsorption.

  14. Reaction kinetics of paddy husk thermal decomposition

    SciTech Connect

    Jain, A.K.; Sharma, S.K.; Singh, D.

    1996-12-31

    Paddy husk production in world is estimated to be around 80 million tons. It has a calorific value of 15 MJ/kg and thus has a tremendous potential as a renewable energy source. Its current uses are: cattle feed, raw material for paper and board, furfural production and silica industries. A large quantity of paddy husk is used in husk fired boiler furnaces at a very low efficiency. For efficient design of husk fired furnaces, reliable data on thermal characteristics of rice husk is essential which is lacking in the literature. In the present study, paddy husk was subjected to Thermogravimetric Analysis at heating rates of 10 and 100 C/min. in a thermal analyzer. The analysis was carried out in air and mixture of oxygen and nitrogen (5:95%) atmosphere. Reaction kinetic parameters such as activation energy, frequency factor and order of reaction have been evaluated and reported. These are relevant to the design of paddy husk fired gasifiers, furnaces and other thermochemical conversion equipment. The results of the thermochemical studies and their potential applications are presented in the paper.

  15. Rice husk ash/calcium oxide/ceria sorbent for simultaneous removal of sulfur dioxide and nitric oxide from flue gas at low temperature

    SciTech Connect

    Dahlan, I.; Lee, K.T.; Kamaruddin, A.H.; Mohamed, A.R.

    2009-06-15

    The reduction of sulfur dioxide (SO{sub 2}) and nitric oxide (NO) emissions has become an isssue of great importance to government regulatory agencies and general public due to their negative effect towards the environment and human health. In this work, the simultaneous removal of sulfur dioxide (SO{sub 2}) and nitric oxide (NO) from simulated flue gas was investigated in a fixed-bed reactor using rice husk ash (RHA)/CaO/CeO{sub 2} sorbent. Attention was focused on the major reactor operation parameters affecting sorption capacity of RHA/CaO/CeO{sub 2} sorbent, which include feed concentration of SO{sub 2} and NO, relative humidity (RH), operating temperature and space velocity (GHSV). This is because such information is unavailable for RHA-based sorbent and the effects of these parameters reported in the literature are also not reliable. Enhancement effect of NO on removal of SO{sub 2} was observed and the presence of SO{sub 2} was essential to the removal of NO. However, at a high level of SO{sub 2}/NO concentration, competition in the sorption of NO and SO{sub 2} on the sorbent active sites might have occurred. RH was found to significantly enhance the SO{sub 2} sorption of the RHA/CaO/CeO{sub 2} sorbent. By contrast, NO sorption capacity decreases when RH was further introduced, as it was not easy to sorb NO in the presence of water. Apart from that, the results also shows that there was a threshold value for the RH to ensure higher SO{sub 2} and NO removal and this value was observed at 50% RH. Higher operating temperatures were favored for SO{sub 2} and NO removal. Nevertheless, beyond 150 degrees C the SO{sub 2} removal was found to decrease. On the other hand, a lower space velocity resulted in a higher SO{sub 2} and NO removal.

  16. The Characteristic and Activation of Mixed Andisol Soil/Bayat Clays/Rice Husk Ash as Adsorbent of Heavy Metal Chromium (Cr)

    NASA Astrophysics Data System (ADS)

    Pranoto; Sajidan; Suprapto, A.

    2017-02-01

    Chromium (Cr) concentration in water can be reduced by adsorption. This study aimed to determine the effect of Andisol soil composition/Bayat clay/husk ash, activation temperature and contact time of the adsorption capacity of Cr in the model solution; the optimum adsorption conditions and the effectiveness of ceramic filters and purifiers to reduce contaminant of Cr in the water. The mixture of Andisol soil, Bayat clay, and husk ash is used as adsorbent of metal ion of Cr(III) using batch method. The identification and characterisation of adsorbent was done with NaF test, infrared spectroscopy (FTIR), X-ray diffraction (XRD). Cr metal concentrations were analyzed by atomic absorption spectroscopy. Sorption isotherms determined by Freundlich equation and Langmuir. The optimum conditions of sorption were achieved at 150°C activation temperature, contact time of 30 minutes and a composition Andisol soil / Bayat clay / husk ash by comparison 80/10/10. The results show a ceramic filter effectively reduces total dissolved solids (TDS) and Chromium in the water with the percentage decrease respectively by 75.91% and 9.44%.

  17. A study on electric conductivity of phosphoric acid supported on nano-pore rice husk silica in H2/Pt/H3PO4 / RHS/Pt/O2 fuel cells.

    PubMed

    Hwang, Moon Jin; Lee, Soo Young; Han, Chong Soo

    2006-11-01

    PEMFC (Polymer Electrolyte Membrane Fuel Cell) is widely considered as an energy conversion system from the chemical energy of hydrogen to electric energy. But, hydrogen fuel obtained from hydrocarbons has trace amount of carbon monoxide which is a potential poison for platinum electrode at the cell operating temperature approximately 100 degrees C and it becomes a huddle for the general usage of PEMFC. On the other hand PAFC (Phosphoric Acid Fuel Cell) operates at a higher temperature and the platinum electrode oxidizes carbon monoxide poison while there is a leakage problem of the liquid phase. To combine the advantages of two fuel cells, the electrolyte systems of phosphoric acid supported silica on ceramics are recently being tested. In this study, we investigated the nm pore rice husk silica as a support for phosphoric acid and tested the electric conductivity of the silica plate and the characteristics of a prototype fuel cell H2/Pt/H3PO4 / RHS/Pt/O2 at 100-200 degrees C. The conductivity of H3PO4/RHS was 8 mS cm(-1) above 175 degrees C under 200 torr H2O. In the fuel cell, the apparent conductance of the electrolyte from I-V characteristics was 2.45 mS/cm at 160 degrees C under 1 atm H2 and air at present.

  18. Identification and Fine Mapping of a White Husk Gene in Barley (Hordeum vulgare L.)

    PubMed Central

    Hua, Wei; Zhang, Xiao-Qi; Zhu, Jinghuan; Shang, Yi; Wang, Junmei; Jia, Qiaojun; Zhang, Qisen; Yang, Jianming; Li, Chengdao

    2016-01-01

    Barley is the only crop in the Poaceae family with adhering husks at maturity. The color of husk at barely development stage could influence the agronomic traits and malting qualities of grains. A barley mutant with a white husk was discovered from the malting barley cultivar Supi 3 and designated wh (white husk). Morphological changes and the genetics of white husk barley were investigated. Husks of the mutant were white at the heading and flowering stages but yellowed at maturity. The diastatic power and α-amino nitrogen contents also significantly increased in wh mutant. Transmission electron microscopy examination showed abnormal chloroplast development in the mutant. Genetic analysis of F2 and BC1F1 populations developed from a cross of wh and Yangnongpi 5 (green husk) showed that the white husk was controlled by a single recessive gene (wh). The wh gene was initially mapped between 49.64 and 51.77 cM on chromosome 3H, which is syntenic with rice chromosome 1 where a white husk gene wlp1 has been isolated. The barley orthologous gene of wlp1 was sequenced from both parents and a 688 bp deletion identified in the wh mutant. We further fine-mapped the wh gene between SSR markers Bmac0067 and Bmag0508a with distances of 0.36 cM and 0.27 cM in an F2 population with 1115 individuals of white husk. However, the wlp1 orthologous gene was mapped outside the interval. New candidate genes were identified based on the barley genome sequence. PMID:27028408

  19. Identification and Fine Mapping of a White Husk Gene in Barley (Hordeum vulgare L.).

    PubMed

    Hua, Wei; Zhang, Xiao-Qi; Zhu, Jinghuan; Shang, Yi; Wang, Junmei; Jia, Qiaojun; Zhang, Qisen; Yang, Jianming; Li, Chengdao

    2016-01-01

    Barley is the only crop in the Poaceae family with adhering husks at maturity. The color of husk at barely development stage could influence the agronomic traits and malting qualities of grains. A barley mutant with a white husk was discovered from the malting barley cultivar Supi 3 and designated wh (white husk). Morphological changes and the genetics of white husk barley were investigated. Husks of the mutant were white at the heading and flowering stages but yellowed at maturity. The diastatic power and α-amino nitrogen contents also significantly increased in wh mutant. Transmission electron microscopy examination showed abnormal chloroplast development in the mutant. Genetic analysis of F2 and BC1F1 populations developed from a cross of wh and Yangnongpi 5 (green husk) showed that the white husk was controlled by a single recessive gene (wh). The wh gene was initially mapped between 49.64 and 51.77 cM on chromosome 3H, which is syntenic with rice chromosome 1 where a white husk gene wlp1 has been isolated. The barley orthologous gene of wlp1 was sequenced from both parents and a 688 bp deletion identified in the wh mutant. We further fine-mapped the wh gene between SSR markers Bmac0067 and Bmag0508a with distances of 0.36 cM and 0.27 cM in an F2 population with 1115 individuals of white husk. However, the wlp1 orthologous gene was mapped outside the interval. New candidate genes were identified based on the barley genome sequence.

  20. How Rice (Oryza sativa L.) Responds to Elevated As under Different Si-Rich Soil Amendments.

    PubMed

    Teasley, William A; Limmer, Matthew A; Seyfferth, Angelia L

    2017-09-19

    Several strategies exist to mitigate As impacts on rice and each has its set of trade-offs with respect to yield, inorganic As content in grain, and CH4 emissions. The addition of Si to paddy soil can decrease As uptake by rice but how rice will respond to elevated As when soil is amended with Si-rich materials is unresolved. Here, we evaluated yield impacts and grain As content and speciation in rice exposed to elevated As in response to different Si-rich soil amendments including rice husk, rice husk ash, and CaSiO3 in a pot study. We found that As-induced yield losses were alleviated by Husk amendment, partially alleviated by Ash amendment, and not affected by CaSiO3 amendment. Furthermore, Husk was the only tested Si-amendment to significantly decrease grain As concentrations. Husk amendment was likely effective at decreasing grain As and improving yield because it provided more plant-available Si, particularly during the reproductive and ripening phases. Both Husk and Ash provided K, which also played a role in yield improvement. This study demonstrates that while Si-rich amendments can affect rice uptake of As, the kinetics of Si dissolution and nutrient availability can also affect As uptake and toxicity in rice.

  1. Moisture diffusivity in rice components during absorption and desorption

    USDA-ARS?s Scientific Manuscript database

    Moisture diffusivity values of different rice kernel components namely, endosperm, bran and husks are required to solve mathematical models describing absorption and desorption processes. In addition to the rice variety and temperature, the moisture diffusivity also depends on its instantaneous mois...

  2. Effects of modifiers on the hydrophobicity of SiO2 films from nano-husk ash

    NASA Astrophysics Data System (ADS)

    Xu, Kejing; Sun, Qingwen; Guo, Yanqing; Dong, Shuhua

    2013-07-01

    Nano-husk ashes were prepared by burning rice-husk with self-propagating method. The super-hydrophobic SiO2 films from nano-husk ash were prepared by sol-gel method using hydroxy silicone oil (HSO), hexamethyldisilazane (HMS), or methyl triethoxysilane (MTS) as modifiers. The effects of modifiers on the hydrophobic property of SiO2 films were studied, and the performances were characterized by the XRD, UV-vis, BET, EDS, SEM, IR, and Contact Angle Analyzer. The results showed that the contact angle of SiO2 films was more than 160° when volume ratio of the modifiers to silicon-sodium solution (SSS) was 0.15. The mechanism of modifiers on SiO2 surfaces is a graft copolymerization. The hydrophobic groups in the modifiers replace the hydroxy groups on SiO2 surfaces and make SiO2 surfaces present super-hydrophobicity.

  3. Sorghum husk biomass as a potential substrate for production of cellulolytic and xylanolytic enzymes by Nocardiopsis sp. KNU.

    PubMed

    Kshirsagar, Siddheshwar D; Bhalkar, Bhumika N; Waghmare, Pankajkumar R; Saratale, Ganesh D; Saratale, Rijuta G; Govindwar, Sanjay P

    2017-07-01

    Nocardiopsis sp. KNU was found to degrade various lignocellulosic waste materials, namely, sorghum husk, sugarcane tops and leaves, wheat straw, and rice husk very efficiently. The strain was found to produce high amounts of cellulase and hemicellulase. Augmentation of cotton seed cake as an organic nitrogen source revealed inductions in activities of endoglucanase, glucoamylase, and xylanase up to 70.03, 447.89, and 275.10 U/ml, respectively. Nonionic surfactant Tween-80 addition was found to enhance the activity of endoglucanase enzyme. Cellulase produced by Nocardiopsis sp. KNU utilizing sorghum husk as a substrate was found to retain its stability in various surfactants up to 90%. The produced enzyme was further tested for saccharification of mild alkali pretreated rice husk. The changes in morphology and functional group were analyzed using scanning electron microscopy and Fourier transform infrared spectroscopy. Enzymatic saccharification confirmed the hydrolytic potential of crude cellulase. The hydrolysate products were analyzed by high-performance thin layer chromatography.

  4. Persistence and metabolism of imidacloprid in rice.

    PubMed

    Akoijam, Romila; Singh, Balwinder

    2014-05-01

    Imidacloprid is a systemic insecticide which gives effective control of plant and leaf hoppers in rice. The persistence and metabolism of imidacloprid in paddy leaves, rice grains, bran, straw and husk were studied following two applications of imidacloprid (Confidor 17.8 SL) @ 20 and 80 g a.i. ha(-1) at an interval of 10 days. Samples of paddy leaves were collected at various time intervals. The samples of rice grains, bran, straw and husk were collected at the time of harvest. The limit of quantification of imidacloprid and its metabolites was worked out to be 0.01 mg kg(-1). The maximum residues of imidacloprid and its metabolites in paddy leaves after 0 day (1 h after last spray) of its application @ 20 and 80 g a.i. ha(-1) were found to be 4.57 and 13.94 mg kg(-1), respectively. These residues could not be detected after 60 and 90 days following last application of imidacloprid at lower and higher dosages, respectively. In rice, olefin metabolite was found to be the main constituent, followed by nitroguanidine, urea, 5-hydroxy, chloronicotinic acid and nitrosimine. The samples of rice grains, bran, straw and husk did not reveal the presence of imidacloprid or its metabolites following its application at both the dosages at harvest.

  5. Composition of liquid rice hull smoke and anti-inflamatory effects in mice

    USDA-ARS?s Scientific Manuscript database

    Antioxidative, antiallergic, and antiinflammatory activities of a new liquid rice hull (husk) smoke extract prepared by pyrolysis of rice hulls followed by liquefaction of the resulting smoke were assessed in vitro and in vivo. At pH 5, the liquid smoke extract inhibited 1-diphenyl-2-picrylhydrazyl ...

  6. Status in physical properties of coloured rice varieties before and after inducing retro-gradation.

    PubMed

    Itagi, HameedaBanu N; Singh, Vasudeva

    2015-12-01

    Three varieties of paddy in brown, red (non-waxy) and black (waxy) forms were de-husked and milled before and after inducing retro-gradation and their physical properties were studied. Normalized grain weight, porosity of parboiled paddy (PP) and its de-husked rice (DR), were high compared to their respective native. True and bulk density were lowest for black variety, its DR, its raw and parboiled forms compared to other varieties of paddy. Angle of repose increased from raw paddy to PP whereas it decreased from raw DR to parboiled DR. Under similar conditions of milling of DR, raw and parboiled milled rice of black variety was the darkest. Raw husk showed higher EMC compared to husk of parboiled. Hardness followed the pattern: Raw: Paddy (~230-280 N) > DR (~120-260 N) > Milled rice (~110 N); for parboiled: DR (~270-480 N) > PP (~260-425 N) > Parboiled milled rice (~250-340 N). Cooking time was high for DR of parboiled ones and least for waxy raw milled rice. Results of this study will be helpful in understanding the quality of pigmented rice cultivars, design and fabrication of some of the equipments in rice processing industry.

  7. Catalytic hydrothermal upgradation of wheat husk.

    PubMed

    Singh, Rawel; Bhaskar, Thallada; Dora, Sambha; Balagurumurthy, Bhavya

    2013-12-01

    Catalytic hydrothermal upgradation of wheat husk was performed at 280°C for 15 min in the presence of alkaline catalysts (KOH and K2CO3). The effect of alkaline catalysts on the yield of bio-oil products and composition of bio-oils obtained were discussed. Total bio-oil yield (31%) comprising of bio-oil1 (ether fraction) and bio-oil2 (acetone fraction) was maximum with K2CO3 solution. Powder XRD (X-ray diffraction) analysis of wheat husk as well as bio-residue samples show that the peaks due to cellulose, hemicellulose and lignin become weak in bio-residue samples which suggest that these components have undergone hydrolytic cleavage/decomposition. The FTIR spectra of bio-oils indicate that the lignin in the wheat husk samples was decomposed to low molecular weight phenolic compounds. (1)H Nuclear Magnetic Resonance (NMR) spectrum of bio-oil1 shows more than 50% of the protons resonate in the up field region from 0.5 ppm to 3.0 ppm.

  8. Bioethanol produced from Moringa oleifera seeds husk

    NASA Astrophysics Data System (ADS)

    Ali, E. N.; Kemat, S. Z.

    2017-06-01

    This paper presents the potential of bioethanol production from Moringa oleifera seeds husk which contains lignocellulosic through Simultaneous Saccharification and Fermentation (SSF) process by using Saccharomyces cerevisiae. This paper investigates the parameters which produce optimum bioethanol yield. The husk was hydrolyzed using NaOH and fermented using Saccharomyces cerevisiae yeast. Batch fermentation was performed with different yeast dosage of 1, 3, and 5 g/L, pH value was 4.5, 5.0 and 5.5, and fermentation time of 3, 6, 9 and 12 hours. The temperature of fermentation process in incubator shaker is kept constant at 32ºC. The samples are then filtered using a 0.20 μm nylon filter syringe. The yield of bioethanol produced was analysed using High Performance Liquid Chromatography (HPLC). The results showed that the highest yield of 29.69 g/L was obtained at 3 hours of fermentation time at pH of 4.5 and using 1g/L yeast. This research work showed that Moringa oleifera seeds husk can be considered to produce bioethanol.

  9. Characterization of humic materials extracted from hazelnut husk and hazelnut husk amended soils.

    PubMed

    Cimen, Funda; Ok, Sonay Sozudogru; Kayran, Ceyhan; Demirci, Sahinde; Bender Ozenc, Damla; Ozenc, Nedim

    2007-06-01

    This study was carried out to determine effects of composted hazelnut husk (CHH) on some chemical properties of soil and soil humic acid (HA). Compost application increases organic matter (OM) content of the soil considerably, OM value of 3.18% became 3.89% in 3 years time interval. Before application of compost, the soil pH was found to be 5.37, while after compost application it became 5.61. FTIR characteristics of humic acid/humic acid-like materials extracted from the original hazelnut husk, composted hazelnut husk and composted hazelnut husk amended soil have been investigated. C and O content of humic acid-like/humic acid materials were in the range of 41.4-50.8% and 37.8-50.5%, respectively. The N content of the humic acid/humic acid-like materials are in the expected range for humic materials which is 2-6%. Comparison of FTIR spectra of hazelnut husk and composted hazelnut husk humic acid-like fractions shows that both exhibit similar but not identical series of IR bands indicating the presence of the same functional groups in both samples. The only difference in the spectra seemed to be a decrement in the peak intensities of composted sample compared to uncomposted one. The similar differentiation of the intensities of IR bands of compost applied soil sample has also been observed. The FTIR spectral results show that the characteristics of composted material tend to become similar to that of soil humic acids characteristics in time.

  10. Isolation and identification of a potent allelopathic substance in rice root exudates.

    PubMed

    Kato-Noguchi, Hisashi; Ino, Takeshi; Sata, Noriko; Yamamura, Shosuke

    2002-07-01

    A search for growth inhibitors in rice root exudates was undertaken in order to clarify the allelopathic system in rice (Oryza sativa L.). Rice seedlings inhibited the growth of cress (Lepidium sativum L.) and lettuce (Lactuca sativa L.) seedlings when the cress and lettuce were grown with rice seedlings. The putative compound causing the inhibitory effect of rice seedlings was isolated from their culture solution, and the chemical structure of the inhibitor was determined by spectral data as momilactone B. Momilactone B inhibited the growth of cress and lettuce seedlings at concentrations greater than 3 and 30 microM, respectively. The concentration of momilactone B was 3.4 and 1.1 nmol per seedling in the culture solutions of husked and non-husked rice seedlings, respectively. These results suggest that rice seedlings may release momilactone B into the environment and the stress caused by the husk-treatment may increase the amount of momilactone B released. Thus, momilactone B may play an important role in rice allelopathy.

  11. Incorporation of hazelnut shell and husk in MDF production.

    PubMed

    Cöpür, Yalçin; Güler, Cengiz; Taşçioğlu, Cihat; Tozluoğlu, Ayhan

    2008-10-01

    Hazelnut shell and husk (Coryllus arellana L.) is an abundant agricultural residue in Turkey and investigating the possibilities of utilizing husk and shell in panel production might help to overcome the raw material shortage that the panel industry is facing. The aim of this work was to investigate the possibilities of utilizing hazelnut shell and husk in medium density fiberboard (MDF) production. To produce general purpose fiberboards, fiber-husk and fiber-shell mixtures at various percentages were examined in this study. The results indicated that panels could be produced utilizing hazelnut husk up to 20% addition without falling below the properties required in the standards. Shell addition was restricted up to 10%, because higher addition levels diminished the elastic modulus and internal bond strength below the acceptable level.

  12. Arsenic accumulation in rice (Oryza sativa L.): human exposure through food chain.

    PubMed

    Azizur Rahman, M; Hasegawa, H; Mahfuzur Rahman, M; Mazid Miah, M A; Tasmin, A

    2008-02-01

    Although human exposure to arsenic is thought to be caused mainly through arsenic-contaminated underground drinking water, the use of this water for irrigation enhances the possibility of arsenic uptake into crop plants. Rice is the staple food grain in Bangladesh. Arsenic content in straw, grain and husk of rice is especially important since paddy fields are extensively irrigated with underground water having high level of arsenic concentration. However, straw and husk are widely used as cattle feed. Arsenic concentration in rice grain was 0.5+/-0.02 mg kg(-1) with the highest concentrations being in grains grown on soil treated with 40 mg As kg(-1) soil. With the average rice consumption between 400 and 650 g/day by typical adults in the arsenic-affected areas of Bangladesh, the intake of arsenic through rice stood at 0.20-0.35 mg/day. With a daily consumption of 4 L drinking water, arsenic intake through drinking water stands at 0.2mg/day. Moreover, when the rice plant was grown in 60 mg of As kg(-1) soil, arsenic concentrations in rice straw were 20.6+/-0.52 at panicle initiation stage and 23.7+/-0.44 at maturity stage, whereas it was 1.6+/-0.20 mg kg(-1) in husk. Cattle drink a considerable amount of water. So alike human beings, arsenic gets deposited into cattle body through rice straw and husk as well as from drinking water which in turn finds a route into the human body. Arsenic intake in human body from rice and cattle could be potentially important and it exists in addition to that from drinking water. Therefore, a hypothesis has been put forward elucidating the possible food chain pathways through which arsenic may enter into human body.

  13. Physicochemical Characterization of various Vietnamese Biomass Residue-derived Biochars (wood, bamboo and risk husk)

    NASA Astrophysics Data System (ADS)

    Nguyen, Hien

    2016-04-01

    This study compares the physico-chemical characteristics of various biocchars produced from biomass residues in Vietnam such as fired wood, rice husk, and bamboo. Wood biochar (WBC), rice husk biochar (RHBC), and bamboo biochar (BBC) were produced under limited oxygen conditions using equipment available locally in Vietnam, known as a Top-Lift Updraft Drum (TLUD). The three biochars are alkaline with pH around 10, but were found to have quite significantly different physico-chemical characteristics. Surface areas (measured by BET) were found to be very significantly higher for WBC and BBC with 479.34 m2/g and 434.53 m2/g, respectively, compared to RHBC (3.29 m2/g). The SEM images correspond with the BET surface area, showing a smooth surface for RHBC, a hollow surface for BBC, and a rough surface for WBC. Total carbon (TC) of WBC and BBC are above 80%, while RHBC has only 47.95% TC. Despite having different TC, the content of hydrogen among the biochars is similar, ranging from 2.07% to 2.34%, and the ratio of H/C also follows the same trend. Thus, although the biochars are produced by the same method, the various feedstocks lead to different physico-chemical properties. Ongoing work is linking these physico-chemical properties to fertiliser efficiencies in terms of nitrate and ammonia adsorption and retention capacities, in order to design optimal biochar properties for use in fertilisation. Key words: physico-chemical characteristic, biochar, surface area, SEM, total carbon, feedstock

  14. Pyrolysis kinetics of hazelnut husk using thermogravimetric analysis.

    PubMed

    Ceylan, Selim; Topçu, Yıldıray

    2014-03-01

    This study aims at investigating physicochemical properties and pyrolysis kinetics of hazelnut husk, an abundant agricultural waste in Turkey. The physicochemical properties were determined by bomb calorimeter, elemental analysis and FT-IR spectroscopy. Physicochemical analysis results showed that hazelnut husk has a high calorimetric value and high volatile matter content. Pyrolysis experiments were carried out in a thermogravimetric analyzer under inert conditions and operated at different heating rates (5, 10, 20°C/min). Three different kinetic models, the iso-conversional Kissinger-Akahira-Sunose (KAS) and Ozawa-Flynn-Wall (OFW) models and Coats-Redfern method were applied on TGA data of hazelnut husk to calculate the kinetic parameters including activation energy, pre-exponential factor and reaction order. Simulation of hazelnut husk pyrolysis using data obtained from TGA analysis showed good agreement with experimental data. Combining with physicochemical properties, it was concluded that this biomass can become useful source of energy or chemicals.

  15. Soil amendments and cultivar selection can improve rice yield in salt-influenced (tsunami-affected) paddy fields in Sri Lanka.

    PubMed

    Reichenauer, Thomas G; Panamulla, Sunil; Subasinghe, Siripala; Wimmer, Bernhard

    2009-10-01

    The tsunami disaster in the Indian Ocean in December 2004 caused devastation of agricultural soils by salt water over wide areas. Many rice fields located close to the coast were affected by the flood of seawater. Electric conductivity (EC) of soils in tsunami-affected rice fields was found to be higher compared to unaffected fields 2 years after the tsunami. Four soil amendments (gypsum, dolomite, cinnamon ash and rice-husk-charcoal) were tested for their influence on improving the yield parameters of rice grown in a tsunami-affected and a non-affected area. Yield parameters were compared with an untreated control of the same cultivar (AT362) and with a salt resistant rice variety (AT354). The salt resistant variety had the highest grain yield. The two amendments gypsum and rice-husk-charcoal led to an increase in grain yield compared to the untreated control, whereas dolomite and cinnamon ash had no significant effect on grain yield.

  16. Compost maturity and nitrogen availability by co-composting of paddy husk and chicken manure amended with clinoptilolite zeolite.

    PubMed

    Latifah, Omar; Ahmed, Osumanu Haruna; Susilawati, Kassim; Majid, Nik Muhamad

    2015-04-01

    The availability of paddy husk from rice processing plants remains high owing to increase in the worldwide rice consumption. Increasing demand for chicken products leads to poultry wastes production. Co-composting of the aforementioned wastes could solve the indiscriminate disposal of these wastes. Thus, co-composting of paddy husk and chicken slurry with clinoptilolite zeolite and urea as additive was carried out. Clinoptilolite zeolite was used to enhance ammonium and nitrate retention in the compost. Temperature of the compost was monitored three times daily for 55 days. Cation exchange capacity, organic matter, ash, humic acids, pH, total C, N, C/N ratio; total P, exchangeable Ca, Mg, K, NH4+, NO3-, and heavy metals contents were determined using standard procedures. pH, total N, humic acids, ash, NH4+, NO3-, P, Ca, Mg, and K contents increased but the salinity, heavy metals contents, and microbial population were low after the co-composting process. Zea mays L. (test crop) seed germination rate in distilled water and the compost were not significantly different. Growth of Spinach oleracea (test crop) on a peat-based growing medium and the compost was also not significantly different. These findings were possible because the clinoptilolite zeolite used in co-composting reduced accumulation of heavy metals that may have damage effects on the test crops. Mature compost with good agronomic properties can be produced by co-composting chicken slurry and paddy husk using clinoptilolite zeolite and urea as additives. © The Author(s) 2015.

  17. Experimental Study on Rise Husk Ash & Fly Ash Based Geo-Polymer Concrete Using M-Sand

    NASA Astrophysics Data System (ADS)

    Nanda Kishore, G.; Gayathri, B.

    2017-08-01

    Serious environmental problems by means of increasing the production of Ordinary Portland cement (OPC), which is conventionally used as the primary binder to produce cement concrete. An attempt has been made to reduce the use of ordinary Portland cement in cement concrete. There is no standard mix design of geo-polymer concrete, an effort has been made to know the physical, chemical properties and optimum mix of geo-polymer concrete mix design. Concrete cubes of 100 x 100 x 100 mm were prepared and cured under steam curing for about 24 hours at temperature range of 40°C to 60°C. Fly ash is replaced partially with rice husk ash at percentage of 10%, 15% and 25%. Sodium hydroxide and sodium silicate are of used as alkaline activators with 5 Molar and 10 Molar NaOH solutions. Natural sand is replaced with manufacture sand. Test results were compared with controlled concrete mix of grade M30. The results shows that as the percentage of rice husk ash and water content increases, compressive strength will be decreases and as molarity of the alkaline solution increases, strength will be increases.

  18. Biotechnological potential of coffee pulp and coffee husk for bioprocesses.

    PubMed

    Pandey; Soccol; Nigam; Brand; Mohan; Roussos

    2000-10-01

    Advances in industrial biotechnology offer potential opportunities for economic utilization of agro-industrial residues such as coffee pulp and coffee husk. Coffee pulp or husk is a fibrous mucilagenous material (sub-product) obtained during the processing of coffee cherries by wet or dry process, respectively. Coffee pulp/husk contains some amount of caffeine and tannins, which makes it toxic in nature, resulting the disposal problem. However, it is rich in organic nature, which makes it an ideal substrate for microbial processes for the production of value-added products. Several solutions and alternative uses of the coffee pulp and husk have been attempted. These include as fertilizers, livestock feed, compost, etc. However, these applications utilize only a fraction of available quantity and are not technically very efficient. Attempts have been made to detoxify it for improved application as feed, and to produce several products such as enzymes, organic acids, flavour and aroma compounds, and mushrooms, etc. from coffee pulp/husk. Solid state fermentation has been mostly employed for bioconversion processes. Factorial design experiments offer useful information for the process optimization. This paper reviews the developments on processes and products developed for the value-addition of coffee pulp/husk through the biotechnological means.

  19. Arsenic concentrations in local aromatic and high-yielding hybrid rice cultivars and the potential health risk: a study in an arsenic hotspot.

    PubMed

    Sandhi, Arifin; Greger, Maria; Landberg, Tommy; Jacks, Gunnar; Bhattacharya, Prosun

    2017-04-01

    The presence of high levels of arsenic (As) in rice fields has negative effects on the health of those consuming rice as their subsistence food. This study determined the variation in total As concentration in local aromatic rice (LAR) (kalijira) and two high-yielding varieties (HYVs) (BRRI dhan 32 and BRRI dhan 28) grown in paddy fields in Matlab, Bangladesh, an As hotspot with elevated As levels in groundwater. Mature rice grain samples and soil samples were collected from different paddy fields, and the As concentrations in both the de-husked grains and the husks of the three rice cultivars were analysed to identify the safest of the three cultivars for human consumption. The results showed that the total As concentration was higher (0.09-0.21 mg As kg(-1)) in the de-husked grains of LAR than in the husks, while the opposite was found for the HYV rice. Moreover, the As concentration in soil samples was 2 to 5-fold higher for the LAR than for the HYVs, but the As accumulation factor (AF) was lower in the LAR (0.2-0.4%) than in the HYVs (0.9-1%). Thus, LAR can be considered the safest of the three cultivars for human consumption owing to its low AF value. Furthermore, due to the low AF, growing LAR instead of HYVs in soils with slightly elevated As levels could help improve the food safety level in the food chain.

  20. Respiratory health of rice millers in Kelantan, Malaysia.

    PubMed

    Musa, R; Naing, L; Ahmad, Z; Kamarul, Y

    2000-09-01

    A cross sectional study was carried out to evaluate the effect of rice husk dust in rice millers in Malaysia. Altogether 69 workers participated in this study. They were interviewed using standardized questionnaires and lung function tests were performed. Chest tightness was among the common symptoms (34.9%) complained by workers. Age, duration of employment and smoking status were among the factors associated with respiratory symptoms (p < 0.01). Lung function tests revealed some degree of impairment compared to the healthy population.

  1. Mechanism study of sulfur fertilization mediating copper translocation and biotransformation in rice (Oryza sativa L.) plants.

    PubMed

    Sun, Lijuan; Yang, Jianjun; Fang, Huaxiang; Xu, Chen; Peng, Cheng; Huang, Haomin; Lu, Lingli; Duan, Dechao; Zhang, Xiangzhi; Shi, Jiyan

    2017-07-01

    Metabolism of sulfur (S) is suggested to be an important factor for the homeostasis and detoxification of Cu in plants. We investigated the effects of S fertilizers (S(0), Na2SO4) on Cu translocation and biotransformation in rice plants by using multiple synchrotron-based techniques. Fertilization of S increased the biomass and yield of rice plants, as well as the translocation factor of Cu from root to shoot and shoot to grain, resulting in enhanced Cu in grain. Sulfur K-edge X-ray near edge structure (XANES) analysis showed that fertilization of S increased the concentration of glutathione in different rice tissues, especially in rice stem and leaf. Copper K-edge XANES results indicated that a much higher proportion of Cu (I) species existed in rice grain than husk and leaf, which was further confirmed by soft X-ray scanning transmission microscopy results. Sulfur increased the proportion of Cu (I) species in rice grain, husk and leaf, suggesting the inducing of Cu (II) reduction in rice tissues by S fertilization. These results suggested that fertilization of S in paddy soils increased the accumulation of Cu in rice grain, possibly due to the reduction of Cu (II) to Cu (I) by enhancing glutathione synthesis and increasing the translocation of Cu from shoot to grain. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Mitigation of arsenic accumulation in rice with water management and silicon fertilization.

    PubMed

    Li, R Y; Stroud, J L; Ma, J F; McGrath, S P; Zhao, F J

    2009-05-15

    Rice represents a major route of As exposure in populations that depend on a rice diet. Practical measures are needed to mitigate the problem of excessive As accumulation in paddy rice. Two potential mitigation methods, management of the water regime and Si fertilization, were investigated under greenhouse conditions. Growing rice aerobically during the entire rice growth duration resulted in the leastAs accumulation. Maintaining aerobic conditions during either vegetative or reproductive stage of rice growth also decreased As accumulation in rice straw and grain significantly compared with rice grown under flooded conditions. The effect of water management regimes was consistent with the observed effect of flooding-induced arsenite mobilization in the soil solution. Aerobic treatments increased the percentage of inorganic As in grain, but the concentrations of inorganic As remained lower than in the flooded rice. Silicon fertilization decreased the total As concentration in straw and grain by 78 and 16%, respectively, even though Si addition increased As concentration in the soil solution. Silicon also significantly influenced As speciation in rice grain and husk by enhancing methylation. Silicon decreased the inorganic As concentration in grain by 59% while increasing the concentration of dimethylarsinic acid (DMA) by 33%. There were also significant differences between two rice genotypes in grain As speciation. This study demonstrated that water management Si fertilization, and selection of rice cultivars are effective measures that can be used to reduce As accumulation in rice.

  3. Dissipation and residues of monosultap in rice plant and environment.

    PubMed

    Zhang, Fengzu; Wang, Lei; Zhou, Li; Pan, Canping

    2012-03-01

    A modified method for the analysis of monosultap residue in rice plant and environment was developed and validated. Monosultap residue dynamics and final residues in supervised field trials at GAP conditions were studied. At fortification levels of 0.05, 0.5 and 1 mg kg(-1), it was shown that recoveries ranged from 75.0% to 109.2% with RSDs of 1.2-5.1% (n = 5). The dissipation experiments showed the half-lives (T(1/2)) of monosultap in water, soil and rice plants were 1.1-1.9, 1.4-2.1 and 1.3-2.1 days, respectively. At pre-harvest intervals (PHI) of 21 and 30 days, monosultap residue were 0.01-0.06 mg kg(-1) in soil, 0.01-0.19 mg kg(-1) in rice plants, and 0.01-0.09 mg kg(-1) in husked rice.

  4. Arsenic accumulation and phosphorus status in two rice (Oryza sativa L.) cultivars surveyed from fields in South China.

    PubMed

    Lu, Ying; Dong, Fei; Deacon, Claire; Chen, Huo-Jun; Raab, Andrea; Meharg, Andrew A

    2010-05-01

    The consumption of paddy rice (Oryza sativa L.) is a major inorganic arsenic exposure pathway in S.E. Asia. A multi-location survey was undertaken in Guangdong Province, South China to assess arsenic accumulation and speciation in 2 rice cultivars, one an Indica and the other a hybrid Indica. The results showed that arsenic concentrations in rice tissue increased in the order grain < husk < straw < root. Rice grain arsenic content of 2 rice cultivars was significant different and correlated with phosphorus concentration and molar ratio of P/As in shoot, being higher for the Indica cultivar than for the hybrid Indica, which suggests altering shoot phosphorus status as a promising route for breeding rice cultivars with reduced grain arsenic. Speciation of grain arsenic, performed using HPLC-ICP-MS, identified inorganic arsenic as the dominant arsenic species present in the rice grain.

  5. Enzymatic hydrolysis of cocoa pod husks. [Trichoderma reesei

    SciTech Connect

    Simpson, B.K.; Oldham, J.H.; Martin, A.M

    1984-07-01

    Laboratory results are presented of the bioconversion of cellulose from cocoa pod husks, utilizing cellulase from three mutants of Trichoderma reesei. Total reducing sugars in filtered hydrolysates were estimated by the dinitrosalicylic acid method. The sugars present were identified by paper chromatography as glucose and xylose.

  6. Sugarcane rice residue biochars and their applications

    NASA Astrophysics Data System (ADS)

    Wang, J. J.

    2014-12-01

    Sugarcane production in U.S. involves either pre-harvest burning or after-harvest burning of the residue. Approximately 70-90% of the dry matter of harvested sugarcane trash is lost through open field burning. This practice has caused considerable concerns over air quality and soil sustainability. We propose an alternative conservation approach to convert the sugarcane residue to biochar and used as soil amendment to conserve carbon and potentially improve soil fertility. In this study, fundamental properties of biochars made from sugarcane residue along with rice residues were tested for agronomic and environmental benefits. Sugarcane and rice harvest residues and milling processing byproducts bagasse and rice husk were converted to biochars at different pyrolysis temperatures and characterized. In general, sugarcane leave biochar contained more P, K, Ca and Mg than sugarcane bagasse biochar. Rice straw biochar had more S, K Ca but less P than rice husk biochar. Both biochars had higher available fraction of total P than that of total K. Sugarcane leave biochar converted at 450oC was dominated with various lignin derived phenols as well as non-specific aromatic compounds whereas bagasse biochar was with both lignin derived phenol and poly aromatic hydrocarbon (PAH). Rice straw char was dominated with non-specific aromatic compounds. At 750oC, charred material was dominated with aromatic ethers while losing the aromatic C=C structures. These molecular and surface property differences likely contributed to the difference in water holding capacities observed with these biochars. On the other hand, rice straw biochars produced at different pyrolysis temperatures had no significant effect on rice germination. Soils treated with sugarcane leave/trash biochar significantly enhanced sugarcane growth especially the root length. Treating soil with either sugarcane leave or bagasse char also enhanced soil adsorption capacity of atrazine; a common herbicide used in sugarcane

  7. [Phytoexclusion potential studies of Si fertilization modes on rice cadmium].

    PubMed

    Chen, Zhe; Tie, Bo-Qing; Lei, Ming; Liu, Xiao-Li; Ye, Chang-Cheng; Luo, Mei-Mei; Mao, Yi-De

    2014-07-01

    The research used serious situ multi-metal contaminated soils to explore Cd repair potential in rice by adding different kinds of fertilizers, based on the outdoor pot experiment. The experiment was consisted of four treatments including non-used fertilizers (CK), the silicon fertilizer applicated into soil (Tsi), the silicon fertilizer applicated as foliar spray (Ysi) and the silicon fertilizer applicated into soil combined with the foliar spray silicon fertilizer application( Tsi + Ysi). The research examined Cd concentrations in tissues of five key growth periods to reveal cadmium (Cd) migration rules, translocation coefficients, rice biomass and yields. The results showed that, compared to CK, different fertilization methods of Si had significant impacts on decreasing Cd in brown rice and polished rice, but not in rice yields; In addition, Tsi + Ysi had the best effects to decrease Cd in edible grains, which resulted in Cd concentrations of husk, brown rice and polished rice reduced by 62.59%, 58.33% and 65.83%, respectively, and the effects of applying Tsi and Ysi were the second. Therefore, Tsi, Ysi and Tsi + Ysi were confirmed to be potential Cd pollution control technologies to rice.

  8. An arsenic-contaminated field trial to assess the uptake and translocation of arsenic by genotypes of rice.

    PubMed

    Lei, Ming; Tie, Baiqing; Zeng, Min; Qing, Pufeng; Song, Zhengguo; Williams, Paul N; Huang, Yizong

    2013-06-01

    Compared to other cereals, rice has particular strong As accumulation. Therefore, it is very important to understand As uptake and translocation among different genotypes. A field study in Chenzhou city, Hunan province of China, was employed to evaluate the effect of arsenic-contaminated soil on uptake and distribution in 34 genotypes of rice (including unpolished rice, husk, shoot, and root). The soil As concentrations ranged from 52.49 to 83.86 mg kg(-1), with mean As concentration 64.44 mg kg(-1). The mean As concentrations in rice plant tissues were different among the 34 rice genotypes. The highest As concentrations were accumulated in rice root (196.27-385.98 mg kg(-1) dry weight), while the lowest was in unpolished rice (0.31-0.52 mg kg(-1) dry weight). The distribution of As in rice tissue and paddy soil are as follows root ≫ soil > shoot > husk > unpolished rice. The ranges of concentrations of inorganic As in all of unpolished rice were from 0.26 to 0.52 mg kg(-1) dry weight. In particular, the percentage of inorganic As in the total As was more than 67 %, indicating that the inorganic As was the predominant species in unpolished rice. The daily dietary intakes of inorganic As in unpolished rice ranged from 0.10 to 0.21 mg for an adult, and from 0.075 to 0.15 mg for a child. Comparison with tolerable daily intakes established by FAO/WHO, inorganic As in most of unpolished rice samples exceeded the recommended intake values. The 34 genotypes of rice were classified into four clusters using a criteria value of rescaled distance between 5 and 10. Among the 34 genotypes, the genotypes II you 416 (II416) with the lowest enrichment of As and the lowest daily dietary intakes of inorganic As could be selected as the main cultivar in As-contaminated field.

  9. Foliar application of two silica sols reduced cadmium accumulation in rice grains.

    PubMed

    Liu, Chuanping; Li, Fangbai; Luo, Chunling; Liu, Xinming; Wang, Shihua; Liu, Tongxu; Li, Xiangdong

    2009-01-30

    In the present study, pot experiments were conducted to investigate the effects of foliar application of two silica (Si) sols on the alleviation of cadmium (Cd) toxicity in contaminated soil to rice. Results showed that the foliar application of Si sols significantly increased the dry weight of grains (without husk) and shoots in rice grown in Cd contaminated soil, whereas the Cd concentration in the grains and shoots decreased obviously. The total accumulation of Cd in rice grains also decreased with the application of both of the Si sols, but no significant effect was found on the Cd accumulation in the shoots. For the optimal effect, Si-sol-B should be foliar applied at the tillering-stage during rice growth. The mechanism of Si foliar application to alleviate the toxicity and accumulation of Cd in grains of rice may be related to the probable Cd sequestration in the shoot cell walls.

  10. Dissipation and residue of pymetrozine in rice field ecosystem.

    PubMed

    Zhang, Yanfeng; Zhang, Li; Xu, Peng; Li, Jianzhong; Wang, Huili

    2015-03-01

    The dissipation and residue of pymetrozine in rice field ecosystem were studied based on a novel and reliable analytical method for pymetrozine in paddy water, soil, rice straw, brown rice, and rice husk. The pymetrozine residues were extracted with acetonitrile and cleaned up by Carb-NH2 SPE cartridge and determined by high-performance liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS-MS). The dissipation of pymetrozine followed first-order kinetics and its half-lives ranged from 1.7 to 1.8 days in paddy water, 5.1 to 5.7 days in soil, and 2.3 to 2.6 days in rice straw, respectively. At harvest time, the highest final residues of pymetrozine varied in soil among three geographical fields and were below the limit of detection in rice tissues. The recommended dosage was considered to be safe for human beings and animals, and the results were helpful in setting maximum residue limit for pymetrozine in rice.

  11. Coffee husk waste for fermentation production of mosquitocidal bacteria.

    PubMed

    Poopathi, Subbiah; Abidha, S

    2011-12-01

    Coffee husk waste (CHW) discarded as bio-organic waste, from coffee industries, is rich in carbohydrates. The current study emphasizes the management of solid waste from agro-industrial residues for the production of biopesticides (Bacillus sphaericus, and B. thuringiensis subsp. israelensis), to control disease transmitting mosquito vectors. An experimental culture medium was prepared by extracting the filtrates from coffee husk. A conventional culture medium (NYSM) also was prepared. The studies revealed that the quantity of mosquitocidal toxins produced from CHW is at par with NYSM. The bacteria produced in these media, were bioassayed against mosquito vectors (Culex quinquefasciatus, Anopheles stephensi, and Aedes aegypti) and it was found that the toxic effect was statistically comparable. Cost-effective analysis have revealed that, production of biopesticides from CHW is highly economical. Therefore, the utilization of CHW provides dual benefits of effective utilization of environmental waste and efficient production of mosquitocidal toxins.

  12. Making sense of HUSK: practice implications for social change initiatives.

    PubMed

    McBeath, Bowen

    2015-01-01

    As an exemplar of bottom-up progressive social experimentation, HUSK provides opportunities to examine how innovative practice is supported and challenged in bureaucratic settings. In this analysis the author uses a sensemaking lens to identify critical issues and questions for those seeking to promote progressive change initiative in social welfare systems. Findings identify essential organizational and managerial supports needed to support service user voice and participation and reinforce the importance of reflexivity in practice and research.

  13. Mucoadhesivity Characterization of Isabgol Husk Mucilage Microspheres Crosslinked by Glutaraldehyde.

    PubMed

    Sharma, Vipin Kumar; Sharma, Prince Prashant; Mazumder, Bhasker; Bhatnagar, Aseem; Singh, Thakuri

    2015-01-01

    The microspheres of Isabgol husk were prepared by emulsification-crosslinking technique and the gastrointestinal transition behavior of the formulation was studied by gamma scintigraphy. The impact of different process variables such as amount of glutaraldehyde, concentration of Isabgol husk and temperature was studied on surface morphology and mucoadhesion. In vitro mucoadhesive testing of formulations was performed by determination of zeta potential, mucus glycoprotein assay and mucus adsorption isotherms. The effect of feeding on retention of microspheres in the gastrointestinal track (GIT) was studied in albino rabbits by gamma scintigraphy study. The results indicated the formation of microspheres as observed by scanning electron microscopy. The smooth and round surfaces of microspheres were obtained on increasing Isabgol husk and glutaraldehyde amount. The positive zeta potential of all formulations indicated the electrostatic interaction as a mechanism of mucoadhesion between the mucus of GIT membranes and the microspheres surfaces. The influence of electrostatic interaction on mucoadhesion of microspheres was again ascertained when the mucin equilibrium adsorption on preparations indicated well fitness in Langmuir and Freundlich adsorption isotherms. During gamma scintigraphy, the stability of (99m)Tc-sodium pertechnetate was found 98.82% at pH 6.8 and 96.78% at pH 7.2, respectively. It indicated the minimal leaching of bound radionuclide from microspheres during gastrointestinal transition as observed in gamma scintigraphic images of the rabbits. The microspheres retained in GIT even after 24 hrs of oral administration. The results indicated the applicability of Isabgol husk mucilage in the development of mucoadhesive microspheres.

  14. Kinetics and isotherms of Neutral Red adsorption on peanut husk.

    PubMed

    Han, Runping; Han, Pan; Cai, Zhaohui; Zhao, Zhenhui; Tang, Mingsheng

    2008-01-01

    Adsorption of Neutral Red (NR) onto peanut husk in aqueous solutions was investigated at 295 K. Experiments were carried out as function of pH, adsorbent dosage, contact time, and initial concentration. The equilibrium adsorption data were analyzed by Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, and Toth isotherm models. The results indicated that the Toth and Langmuir models provided the best correlation of the experimental data. The adsorption capacity of peanut husk for the removal of NR was determined with the Langmuir and found to be 37.5 mg/g at 295 K. The adsorption kinetic data were modeled using the pseudo-first order, pseudo-second order, and intra-particle diffusion kinetic equations. It was seen that the pseudo-first order and pseudo-second order kinetic equations could describe the adsorption kinetics. The intraparticle diffusion model was also used to express the adsorption process at the two-step stage. It was implied that peanut husk may be suitable as adsorbent material for adsorption of NR from aqueous solutions.

  15. Impacts of soil incorporation of pre-incubated silica-rich rice residue on soil biogeochemistry and greenhouse gas fluxes under flooding and drying.

    PubMed

    Gutekunst, Madison Y; Vargas, Rodrigo; Seyfferth, Angelia L

    2017-09-01

    Incorporation of silica-rich rice husk residue into flooded paddy soil decreases arsenic uptake by rice. However, the impact of this practice on soil greenhouse gas (GHG) emissions and elemental cycling is unresolved particularly as amended soils experience recurrent flooding and drying cycles. We evaluated the impact of pre-incubated silica-rich rice residue incorporation to soils on pore water chemistry and soil GHG fluxes (i.e., CO2, CH4, N2O) over a flooding and drying cycle typical of flooded rice cultivation. Soils pre-incubated with rice husk had 4-fold higher pore water Si than control and 2-fold higher than soils pre-incubated with rice straw, whereas the pore water As and Fe concentrations in soils amended with pre-incubated straw and husk were unexpectedly similar (maximum ~0.85μM and ~450μM levels, respectively). Pre-incubation of residues did not affect Si but did affect the pore water levels of As and Fe compared to previous studies using fresh residues where straw amended soils had higher As and Fe in pore water. The global warming potential (GWP) of soil GHG emissions decreased in the order straw (612±76g CO2-eqm(-2))>husk (367±42gCO2-eqm(-2))>ashed husk=ashed straw (251±26 and 278±28gCO2-eqm(-2))>control (186±23gCO2-eqm(-2)). The GWP increase due to pre-incubated straw amendment was due to: a) larger N2O fluxes during re-flooding; b) smaller contributions from larger CH4 fluxes during flooded periods; and c) higher CH4 and CO2 fluxes at the onset of drainage. In contrast, the GWP of the husk amendment was dominated by CO2 and CH4 emissions during flooded and drainage periods, while ashed amendments increased CO2 emissions particularly during drainage. This experiment shows that ashed residues and husk addition minimizes GWP of flooded soils and enhances pore water Si compared to straw addition even after pre-incubation. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Rice bran: a novel functional ingredient.

    PubMed

    Sharif, Mian Kamran; Butt, Masood Sadiq; Anjum, Faqir Muhammad; Khan, Saima Hafiz

    2014-01-01

    Rice (Oryza sativa) is the most important staple food for a large part of the world's human population, especially in East and South Asia, the Middle East, Latin America, and the West Indies. It provides more than one fifth of the calories consumed worldwide by the human. It is the second leading cereal crop and staple food of half of the world's population. It is grown in at least 114 countries with global production of 645 million tons; share of Asian farmers is about 90% of the total produce. Rice bran, brown outer layer of rice kernel, is mainly composed of pericarp, aleurone, subaleurone layer, and germ. It contains appreciable quantities of nutrients like protein, fat, and dietary fiber. Furthermore, it contains substantial amount of minerals like K, Ca, Mg, and Fe. Presence of antioxidants like tocopherols, tocotrienols, and γ-oryzanol also brighten prospects of rice bran utilization for humans as functional ingredient to mitigate the life-threatening disorders. Moreover, in the developing countries, budding dilemma of food crisis, arising due to lower crop yields and escalating population, needs to utilize each pent of available resources. To provide enough food to all people, there is the holistic approach of using the by-products generated during food processing and preparations. Rice is being processed in well-established industry, but the major apprehension is the utilization of its by-products; rice bran (5-8%) and polishing (2-3%) that are going as waste. Rice processing or milling produces several streams of materials including milled rice, bran, and husk. In developing countries, rice bran is considered as a by-product of the milling process and commonly used in animal feed or discarded as a waste. The potential of producing rice bran at the global level is 29.3 million tons annually, whereas the share of Pakistan is worked out to be 0.5 million tons. In present paper, attempt has been made to highlight the significance of these valuable but

  17. Frictional and heat resistance characteristics of coconut husk particle filled automotive brake pad

    NASA Astrophysics Data System (ADS)

    Bahari, Shahril Anuar; Chik, Mohd Syahrizul; Kassim, Masitah Abu; Som Said, Che Mohamad; Misnon, Mohd Iqbal; Mohamed, Zulkifli; Othman, Eliasidi Abu

    2012-06-01

    The objective of this study was to determine the friction and heat resistance characteristics of automotive brake pad composed with different sizes and percentages of coconut husk particle. The materials used were phenolic resin (phenol formaldehyde) as binder, copper, graphite and brass as friction producer/modifiers, magnesium oxide as abrasive material, steel and barium sulfate as reinforcement while coconut husk particle as filler. To obtain particle, the coconut husk was ground and dried to 3% moisture content. Then the coconut husk particle was screened using 80 mesh (to obtain coarse dust) and 100 mesh (to obtain fine dust). Different percentages of particle, such as 10 and 30% were used in the mixture of brake pad materials. Then the mixture was hot-pressed to produce brake pad. Chase machine was used to determine the friction coefficient in friction resistance testing, while thermogravimetric analyzer (TGA) machine was used to determine the heat decomposition values in heat resistance testing. Results showed that brake pad with 100 mesh and 10% composition of coconut husk particle showed the highest friction coefficient. For heat resistance, brake pad with 100 mesh and 30% composition of coconut husk dust showed the highest decomposition temperature, due to the high percentage of coconut husk particle in the composition, thus increased the thermal stability. As a comparison, brake pad composed with coconut husk particle showed better heat resistance results than commercial brake pad.

  18. Evidence for mid-Holocene rice domestication in the Americas.

    PubMed

    Hilbert, Lautaro; Neves, Eduardo Góes; Pugliese, Francisco; Whitney, Bronwen S; Shock, Myrtle; Veasey, Elizabeth; Zimpel, Carlos Augusto; Iriarte, José

    2017-10-09

    The development of agriculture is one of humankind's most pivotal achievements. Questions about plant domestication and the origins of agriculture have engaged scholars for well over a century, with implications for understanding its legacy on global subsistence strategies, plant distribution, population health and the global methane budget. Rice is one of the most important crops to be domesticated globally, with both Asia (Oryza sativa L.) and Africa (Oryza glaberrima Steud.) discussed as primary centres of domestication. However, until now the pre-Columbian domestication of rice in the Americas has not been documented. Here we document the domestication of Oryza sp. wild rice by the mid-Holocene residents of the Monte Castelo shell mound starting at approximately 4,000 cal. yr BP, evidenced by increasingly larger rice husk phytoliths. Our data provide evidence for the domestication of wild rice in a region of the Amazon that was also probably the cradle of domestication of other major crops such as cassava (Manihot esculenta), peanut (Arachis hypogaea) and chilli pepper (Capsicum sp.). These results underline the role of wetlands as prime habitats for plant domestication worldwide.4,000-year-old phytoliths (plant microfossils) from the Monte Castelo shell mound (southwestern Amazonia) provide evidence for an independent rice domestication event in the Americas.

  19. Anti-inflammatory effects of Zea mays L. husk extracts.

    PubMed

    Roh, Kyung-Baeg; Kim, Hyoyoung; Shin, Seungwoo; Kim, Young-Soo; Lee, Jung-A; Kim, Mi Ok; Jung, Eunsun; Lee, Jongsung; Park, Deokhoon

    2016-08-19

    Zea mays L. (Z. mays) has been used for human consumption in the various forms of meal, cooking oil, thickener in sauces and puddings, sweetener in processed food and beverage products, bio-disel. However, especially, in case of husk extract of Z. mays, little is known about its anti-inflammatory effects. Therefore, in this study, the anti-inflammatory effects of Z. mays husk extract (ZMHE) and its mechanisms of action were investigated. The husks of Z. Mays were harvested in kangwondo, Korea. To assess the anti-inflammatory activities of ZMHE, we examined effects of ZMHE on nitric oxide (NO) production, and release of soluble intercellular adhesion molecule-1 (sICAM-1) and eotaxin-1. The expression level of inducible nitric oxide synthase (iNOS) gene was also determined by Western blot and luciferase reporter assays. To determine its mechanisms of action, a luciferase reporter assay for nuclear factor kappa B (NF-kB) and activator protein-1 (AP-1) was introduced. ZMHE inhibited lipopolysaccharide (LPS)-induced production of NO in RAW264.7 cells. In addition, expression of iNOS gene was reduced, as confirmed by Western blot and luciferase reporter assays. Effects of ZMHE on the AP-1 and NF-kB promoters were examined to elucidate the mechanism of its anti-inflammatory activity. Activation of AP-1 and NF-kB promoters induced by LPS was significantly reduced by ZMHE treatment. In addition, LPS-induced production of sICAM-1 and IL-4-induced production of eotaxin-1 were all reduced by ZMHE. Our results indicate that ZMHE has anti-inflammatory effects by downregulating the expression of iNOS gene and its downregulation is mediated by inhibiting NF-kB and AP-1 signaling.

  20. Antioxidant compounds from Algerian Convolvulus tricolor (Convolvulaceae) seed husks.

    PubMed

    Kacem, Nassira; Hay, Anne-Emmanuelle; Marston, Andrew; Zellagui, Amar; Rhouati, Salah; Hostettmann, Kurt

    2012-07-01

    Seed husk extracts of Convolvulus tricolor L. (Convolvulaceae) afforded six compounds, identified for the first time from this plant: isorhamnetin 3-O-beta-D-galactopyranoside (1), isorhamnetin 3-O-beta-D-(6"-acetyl)-galactopyranoside (2), isorhamnetin 3-O-robinobioside (3), 3,4-di-O-caffeoylquinic acid (4), gentisic acid 5-O-glucoside (5), and scopoletin (6). Separation of compounds was carried out by CC and CPC. Structural elucidations were performed by HPLC-UV-DAD, HPLC-ESI/MS (negative mode) and NMR.

  1. Degradation kinetics of the insecticide spinetoram in a rice field ecosystem.

    PubMed

    Zhao, Li; Chen, Guo; Zhao, Jian; Zhang, Yan; Zhu, Yong; Yang, Ting; Wu, Yin-Liang

    2015-01-01

    The fate of spinetoram was studied in a rice field ecosystem, and an efficient method for the determination of spinetoram (XDE-175-J and XDE-175-L) in soil, rice straw, paddy water, husk and brown rice was developed. Spinetoram residues were extracted from samples with a salting out extraction procedure. The extracts were diluted with 0.10% formic acid in water and analysed with liquid chromatography tandem mass spectrometry (LC-MS/MS) on a Waters Acquity BEH C18 column. The calibration curve was linear in the range 0.125-100 μg L(-1) and r>0.999. The average recovery was 82.9-89.0% from soil, 78.5-92.1% from rice straw, 93.6-100.3% from paddy water, 79.1-87.9% from brown rice and 72.7-82.9% from husk. The relative standard deviation (RSD) was less than 10%. These results are all within the accepted range for pesticide residue determination. The field test results showed that spinetoram degradation in paddy water, soil and rice straw coincided with C=0.0132e(-1.9685t), C=0.0308e(-0.1018t) and C=0.8530e(-0.6223t), respectively. The half-lives of spinetoram in paddy water, soil and rice straw were 0.35, 6.8 and 1.1 d, respectively. The final residue level was lower than the maximum residue limit (MRL) of 0.05 mg kg(-1) for spinetoram in rice with a harvest interval of 7d. A dosage of 450 mL ha(-1) was recommended, which can be considered safe for human beings and animals. The results of this study will contribute to establishing the scientific basis of the dosage of spinetoram for agricultural fields.

  2. Preparation of food grade carboxymethyl cellulose from corn husk agrowaste.

    PubMed

    Mondal, Md Ibrahim H; Yeasmin, Mst Sarmina; Rahman, Md Saifur

    2015-08-01

    Alpha-cellulose extracted from corn husks was used as the raw material for the production of food-grade carboxymethyl cellulose (CMC). Preparation of CMC from husk cellulose was carried out by an etherification process, using sodium hydroxide and monochloroacetic acid (MCA), with ethanol as the supporting medium. Characterizations of CMC were carried out by analyzing the spectra of FTIR, XRD patterns and SEM photomicrographs. Degree of substitution (DS) was determined with respect to particle size using chemical methods. Solubility, molecular weight and DS of CMC increased with decreased cellulose particle sizes. Microbiological testing of the prepared CMC was done by the pour plate method. Concentrations of heavy metals such as arsenic, lead, cadmium and mercury in the purified CMC were measured by Atomic Absorption Spectroscopy technique and found to be within the WHO/FAO recommended value. A comparative study with CMC available in the international market was conducted. The purity of the prepared CMC was higher, at 99.99% well above the purity of 99.5% for standard CMC. High purity CMC showed a yield 2.4 g/g with DS 2.41, water holding capacity 5.11 g/g, oil holding capacity 1.59 g/g. The obtained product is well suited for pharmaceutical and food additives.

  3. Antimicrobial activity of fermented Theobroma cacao pod husk extract.

    PubMed

    Santos, R X; Oliveira, D A; Sodré, G A; Gosmann, G; Brendel, M; Pungartnik, C

    2014-09-26

    Theobroma cacao L. contains more than 500 different chemical compounds some of which have been traditionally used for their antioxidant, anti-carcinogenic, immunomodulatory, vasodilatory, analgesic, and antimicrobial activities. Spontaneous aerobic fermentation of cacao husks yields a crude husk extract (CHE) with antimicrobial activity. CHE was fractioned by solvent partition with polar solvent extraction or by silica gel chromatography and a total of 12 sub-fractions were analyzed for chemical composition and bioactivity. CHE was effective against the yeast Saccharomyces cerevisiae and the basidiomycete Moniliophthora perniciosa. Antibacterial activity was determined using 6 strains: Staphylococcus aureus, Staphylococcus epidermidis, and Bacillus subtilis (Gram-positive) and Pseudomonas aeruginosa, Klebsiella pneumoniae, and Salmonella choleraesuis (Gram-negative). At doses up to 10 mg/mL, CHE was not effective against the Gram-positive bacteria tested but against medically important P. aeruginosa and S. choleraesuis with a minimum inhibitory concentration (MIC) of 5.0 mg/mL. Sub-fractions varied widely in activity and strongest antibacterial activity was seen with CHE8 against S. choleraesuis (MIC of 1.0 mg/mL) and CHE9 against S. epidermidis (MIC of 2.5 mg/mL). All bioactive CHE fractions contained phenols, steroids, or terpenes, but no saponins. Fraction CHE9 contained flavonoids, phenolics, steroids, and terpenes, amino acids, and alkaloids, while CHE12 had the same compounds but lacked flavonoids.

  4. Anaerobic treatment of coconut husk liquor for biogas production.

    PubMed

    Leitão, R C; Araújo, A M; Freitas-Neto, M A; Rosa, M F; Santaella, S T

    2009-01-01

    The market for coconut water causes environmental problems as it is one of the major agro-industrial solid wastes in some developing countries. With the aim of reusing the coconut husk, Embrapa developed a system for processing this raw material. During the dewatering stage Coconut Husk Liquor (CHL) is generated with chemical oxygen demand (COD) varying from 60 to 70 g/L due to high concentrations of sugars and tannins. The present study evaluated the feasibility of anaerobic treatment of CHL through Anaerobic Toxicity Assay and the operation of a lab-scale Upflow Anaerobic Sludge Blanket (UASB) reactor. Results showed that CHL can be treated through a UASB reactor operating with an OLR that reaches up to 10 kg/m3.d and that is maintained stable during the whole operation. With this operational condition, the removal efficiency was higher than 80% for COD and approximately 78% for total tannins, and biogas production was 20 m3 of biogas or 130 KWh per m3 of CHL. Seventy-five percent of the biogas composition was methane and toxicity tests demonstrated that CHL was not toxic to the methanogenic consortia. Conversely, increasing the concentration of CHL leads to increased methanogenic activity.

  5. Increased water resistance of CTMP fibers by oat (Avena sativa L.) husk lignin.

    PubMed

    Sipponen, Mika H; Pastinen, Ossi A; Strengell, Reetta; Hyötyläinen, Juha M I; Heiskanen, Isto T; Laakso, Simo

    2010-12-13

    The insertion of oat husk lignin onto chemithermomechanical pulp (CTMP) fibers was studied to increase fiber hydrophobicity. The pretreated pulp samples were subsequently used for preparation of handsheets for characterization. Treatment of CTMP with laccase in the presence of oat husk lignin resulted in a significant increase in hydrophobicity of the handsheet surface, as indicated by dynamic contact angle analysis. Water absorption time of 8 s was obtained with initial contact angle of 118°. Although the handsheet's brightness was reduced by 33%, tensile index was only subtly decreased. Neither laccase nor oat husk lignin alone gave much improved water absorption times. Therefore, handsheets made of laccase-treated pulp with and without oat husk lignin were further examined by XPS, which suggested that both laccase and oat husk lignin were inserted onto CTMP fibers. The oat husk lignin was distributed as heterogeneous aggregates on the handsheet surface whereas laccase was uniformly distributed. Evidence was obtained that the adsorbed laccase layer formed a noncovalent base for the insertion of oat husk lignin onto fiber surfaces.

  6. Comet assay to assess the genotoxicity of Persian walnut (Juglans regia L.) husks with statistical evaluation.

    PubMed

    Petriccione, Milena; Ciniglia, Claudia

    2012-07-01

    The aim of this study was to confirm the utility of the Comet assay as a genotoxicity screening test for evaluating the impact of walnut husk aqueous extract. Phytotoxicity assays using diluted and undiluted walnut husk aqueous extracts were performed on young roots of Raphanus sativus (radish), and the Comet assay was used to evaluate DNA integrity in isolated radish radicle nuclei. The results reveal a dose-dependent accumulation of DNA damage in radish radicles treated with walnut husks water extract and that the Kolmogorov-Smirnov test combined with Johnson SB distribution was the best approach for describing Comet assay data.

  7. MicroCT reveals domesticated rice (Oryza sativa) within pottery sherds from early Neolithic sites (4150-3265 cal BP) in Southeast Asia.

    PubMed

    Barron, Aleese; Turner, Michael; Beeching, Levi; Bellwood, Peter; Piper, Philip; Grono, Elle; Jones, Rebecca; Oxenham, Marc; Kien, Nguyen Khanh Trung; Senden, Tim; Denham, Tim

    2017-08-07

    Rice (Oryza sativa) was domesticated in the Yangtze Valley region at least 6000-8000 years ago, yet the timing of dispersal of domesticated rice to Southeast Asia is contentious. Often rice is not well-preserved in archaeobotanical assemblages at early Neolithic sites in the wet tropics of Southeast Asia and consequently rice impressions in pottery have been used as a proxy for rice cultivation despite their uncertain taxonomic and domestication status. In this research, we use microCT technology to determine the 3D microscale morphology of rice husk and spikelet base inclusions within pottery sherds from early Neolithic sites in Vietnam. In contrast to surface impressions, microCT provides images of the entire husk and spikelet base preserved within the pottery, including the abscission scar characteristic of domesticated rice. This research demonstrates the potential of microCT to be a new, non-destructive method for the identification of domesticated plant remains within pottery sherds, especially in contexts where archaeobotanical preservation is poor and chaff-tempered sherds are rare and unavailable for destructive analysis. The method has the potential to greatly advance the understanding of crop domestication and agricultural dispersal for ceramic cultures in different parts of the world.

  8. Accumulation of mercury and cadmium in rice from paddy soil near a mercury mine.

    PubMed

    Li, W C; Ouyang, Y; Ye, Z H

    2014-11-01

    Paddy soil and rice (Oryza sativa L.) in the Wanshan mining area in Guizhou Province, China, have been contaminated by toxic trace metals such as cadmium (Cd) and mercury (Hg). The present study examined correlations between the types and physicochemical parameters of the soil and the contents of trace metals and the different forms of Hg in rice. The health risks of consuming contaminated rice from the Wanshan mining area were also assessed. Sequential extraction procedures were used to investigate the chemical behavior of Hg in the soil. The results showed that Hg and Cd were the most abundant trace metals in the Wanshan mining area. The toxic methylmercury (MeHg) content was substantial in brown rice, and the total amounts of total Hg (THg), diethylenetriaminepentaacetic acid-Hg, and water-soluble Hg varied in the rhizosphere and non-rhizosphere soils. An antagonistic interaction between Mn in brown rice, straw, and husk and MeHg in brown rice was also shown. An analysis of calculated dietary intake, target hazard quotients, and hazard indexes showed a potential risk of transferring Hg, MeHg, and Cd to humans when rice from the Wanshan mining area is consumed. Therefore, it must be concluded that consuming contaminated rice near the Wanshan mining area is a potential threat to human health. © 2014 SETAC.

  9. Logistics cost analysis of rice residues for second generation bioenergy production in Ghana.

    PubMed

    Vijay Ramamurthi, Pooja; Cristina Fernandes, Maria; Sieverts Nielsen, Per; Pedro Nunes, Clemente

    2014-12-01

    This study explores the techno-economic potential of rice residues as a bioenergy resource to meet Ghana's energy demands. Major rice growing regions of Ghana have 70-90% of residues available for bioenergy production. To ensure cost-effective biomass logistics, a thorough cost analysis was made for two bioenergy routes. Logistics costs for a 5 MWe straw combustion plant were 39.01, 47.52 and 47.89 USD/t for Northern, Ashanti and Volta regions respectively. Logistics cost for a 0.25 MWe husk gasification plant (with roundtrip distance 10 km) was 2.64 USD/t in all regions. Capital cost (66-72%) contributes significantly to total logistics costs of straw, however for husk logistics, staff (40%) and operation and maintenance costs (46%) dominate. Baling is the major processing logistic cost for straw, contributing to 46-48% of total costs. Scale of straw unit does not have a large impact on logistic costs. Transport distance of husks has considerable impact on logistic costs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Rice husk ash (RHA) as cement admixture for immobilization of liquid radioactive waste at different temperatures

    NASA Astrophysics Data System (ADS)

    El-Dakroury, A.; Gasser, M. S.

    2008-11-01

    Cementitious materials will initially act as a mechanical barrier preventing activated water flow through the waste for a long time, and thus will contribute to the retardation of dissolved radionuclides by the combination of physical and chemical interactions. Most chemical species in aqueous solutions will undergo some kind of (chemical) interactions with any solids of the cementations material. Therefore, it is of great importance to develop a quantitative understanding of the chemical processes involved and to strictly differentiate between physical and chemical aspects of radionuclide transport through such materials. A study is undertaken to determine the waste immobilization performance of (Cs +) wastes in cement-RHA mixtures. In addition to evaluating the effects of RHA on the leaching properties of cemented waste forms, the effect of addition of (RHA) on the strength of the cemented waste form is also investigated. However, RHA addition of 30% causes a significant increase in the hydraulic stability of cemented waste form. RHA enhances the strength; leaching and durability of cement may be through three primary actions which are the filler effect, the acceleration of ordinary Portland cement hydration and the pozzolanic reaction with calcium hydroxide (CH). The results were compared to control sample, and the viability of the RHA addition to concrete was verified. The use of these minerals results in ecological, economic and energy saving considerations.

  11. Cellulose nanowhiskers from coconut husk fibers: effect of preparation conditions on their thermal and morphological behavior

    USDA-ARS?s Scientific Manuscript database

    Cellulose nanowhiskers were prepared by sulfuric acid hydrolysis from coconut husk fibers which had previously been submitted to a delignification process. The effects of preparation conditions on the thermal and morphological behavior of the nanocrystals were investigated. Cellulose nanowhisker sus...

  12. Nanotubes, nanobelts, nanowires, and nanorods of silicon carbide from the wheat husks

    SciTech Connect

    Qadri, S. B.; Rath, B. B.; Gorzkowski, E. P.; Feng, J.; Qadri, S. N.; Caldwell, J. D.

    2015-09-14

    Nanotubes, nanowires, nanobelts, and nanorods of SiC were synthesized from the thermal treatment of wheat husks at temperatures in excess of 1450 °C. From the analysis based on x-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy, it has been found that the processed samples of wheat husk consisted of 2H and 3C polytypes of SiC exhibiting the nanostructure shapes. These nanostructures of silicon carbide formed from wheat husks are of technological importance for designing advance composites, applications in biotechnology, and electro-optics. The thermodynamics of the formation of SiC is discussed in terms of the rapid solid state reaction between hydrocarbons and silica on the molecular scale, which is inherently present in the wheat husks.

  13. Isolation and characterization of cellulose nanofibrils from arecanut husk fibre.

    PubMed

    C S, Julie Chandra; George, Neena; Narayanankutty, Sunil K

    2016-05-20

    The isolation of cellulose nanofibres from arecanut husk was achieved by a chemo-mechanical method thereby opening up a means for utilizing a waste product more effectively. The chemical processes involved alkali treatment, acid hydrolysis, and bleaching. The mechanical fibrillation was performed via grinding and homogenization. The chemical constituents at different stages of treatment of fibres were analyzed according to the ASTM standards. Morphological characterization was done using the scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The isolated nanofibers had an average diameter of below 10 nanometres and a very high aspect ratio in the range 120-150. Fourier transform infrared spectroscopy (FT-IR) showed the effective removal of the non cellulosic components. The crystallinity was increased with successive treatments as shown by the X-ray diffraction analysis (XRD). The TGA studies revealed a good thermal stability for the isolated nanofibres.

  14. Development of edible films based on Brazilian pine seed (Araucaria angustifolia) flour reinforced with husk powder

    USDA-ARS?s Scientific Manuscript database

    The aim of this study was to develop edible films based on pinhão flour reinforced with pinhão husk powder. For this, six formulations were developed using 5.0% pinhão flour with 1.5% glycerol base and adding 0.5, 1.0, 1.5, 2.0 and 2.5% of pinhão husk where the pure base served as the control. The ...

  15. Grain Unloading of Arsenic Species in Rice

    SciTech Connect

    Carey, Anne-Marie; Scheckel, Kirk G.; Lombi, Enzo; Newville, Matt; Choi, Yongseong; Norton, Gareth J.; Charnock, John M.; Feldmann, Joerg; Price, Adam H.; Meharg, Andrew A.

    2010-01-11

    Rice (Oryza sativa) is the staple food for over half the world's population yet may represent a significant dietary source of inorganic arsenic (As), a nonthreshold, class 1 human carcinogen. Rice grain As is dominated by the inorganic species, and the organic species dimethylarsinic acid (DMA). To investigate how As species are unloaded into grain rice, panicles were excised during grain filling and hydroponically pulsed with arsenite, arsenate, glutathione-complexed As, or DMA. Total As concentrations in flag leaf, grain, and husk, were quantified by inductively coupled plasma mass spectroscopy and As speciation in the fresh grain was determined by x-ray absorption near-edge spectroscopy. The roles of phloem and xylem transport were investigated by applying a {+-} stem-girdling treatment to a second set of panicles, limiting phloem transport to the grain in panicles pulsed with arsenite or DMA. The results demonstrate that DMA is translocated to the rice grain with over an order magnitude greater efficiency than inorganic species and is more mobile than arsenite in both the phloem and the xylem. Phloem transport accounted for 90% of arsenite, and 55% of DMA, transport to the grain. Synchrotron x-ray fluorescence mapping and fluorescence microtomography revealed marked differences in the pattern of As unloading into the grain between DMA and arsenite-challenged grain. Arsenite was retained in the ovular vascular trace and DMA dispersed throughout the external grain parts and into the endosperm. This study also demonstrates that DMA speciation is altered in planta, potentially through complexation with thiols.

  16. Husk Tomato (Physalis ixocarpa Brot.) Waste as a Promising Source of Pectin: Extraction and Physicochemical Characterization.

    PubMed

    Morales-Contreras, Blanca Elizabeth; Contreras-Esquivel, Juan Carlos; Wicker, Louise; Ochoa-Martínez, Luz Araceli; Morales-Castro, Juliana

    2017-07-01

    Husk tomato (Physalis ixocarpa Brot. var. Rendidora) waste was evaluated as a source of specialized pectin, and pectin extracted from this waste was characterized physicochemically. Fruit was blanched for 10 or 15 min and extracted in 0.1 N HCl for 15 to 25 min. Extracted pectin was subjected to physicochemical analysis. For all extraction conditions, the percentage of anhydrogalacturonic acid exceeded 60%, indicating that husk tomato was a good source of pectin. The degree of esterification of pectin molecules was 63% to 91%. The amount of extracted pectin decreased with increasing extraction time. The apparent viscosity of husk tomato pectin showed the characteristic behavior of pseudoplastic fluids. Neutral sugars were identified, and the amounts of 6 sugars (fucose, rhamnose, arabinose, galactose, glucose, and xylose) were quantified. Sugars identified in husk tomato pectin and present in the Rhamnogalacturonan I region, arabinose, galactose, and rhamnose suggest a highly branched structure, which will influence its future applications. Molecular weight values were 542 to 699 kDa, exceeding molecular weight values reported for commercial citrus pectins from 134 to 480 kDa. The extraction process significantly (P < 0.05) influenced the physicochemical properties of pectin. Up to 19.8% from the total amount of pectin in the husk tomato was extracted by 10 min of blanching and 20 min of a more heat treatment. Our findings indicate that husk tomato can be a good alternative source of pectin having highly distinctive physicochemical characteristics. © 2017 Institute of Food Technologists®.

  17. Physical, chemical and mechanical properties of pehuen cellulosic husk and its pehuen-starch based composites.

    PubMed

    Castaño, J; Rodríguez-Llamazares, S; Carrasco, C; Bouza, R

    2012-11-06

    Pehuen cellulosic husk was characterized and employed as reinforcement for composite materials. In this research, thermoplastic pehuen starch (TPS) and TPS/poly(lactic acid) (PLA)/polyvinyl alcohol (PVA) composites, reinforced with 5 and 10% of pehuen husk, were prepared by melt-blending. Comparative samples of pehuen TPS and TPS/PLA/PVA blend were also studied. Physical, thermal, structural and mechanical properties of composites were evaluated. Pehuen husk mainly consists of cellulose (50 wt%), hemicellulose (30 wt%) and lignin (14 wt%). In respect to lipids, this husk has only a 0.6 wt%. Its surface is smooth and damage-free and it is decomposed above 325 °C. The incorporation of pehuen husk improved considerably the thermal stability and mechanical properties of the studied composites, mainly in TPS composites. Their thermal stability enhances since biofiber hinders the "out-diffusion" of volatile molecules from the polymer matrix, while mechanical properties could raise due to the natural affinity between husk and starch in the pehuen seed. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Accumulation of total mercury and methylmercury in rice plants collected from different mining areas in China.

    PubMed

    Meng, Mei; Li, Bing; Shao, Jun-juan; Wang, Thanh; He, Bin; Shi, Jian-bo; Ye, Zhi-hong; Jiang, Gui-bin

    2014-01-01

    A total of 155 rice plants were collected from ten mining areas in three provinces of China (Hunan, Guizhou and Guangdong), where most of mercury (Hg) mining takes place in China. During the harvest season, whole rice plants were sampled and divided into root, stalk & leaf, husk and seed (brown rice), together with soil from root zone. Although the degree of Hg contamination varied significantly among different mining areas, rice seed showed the highest ability for methylmercury (MeHg) accumulation. Both concentrations of total mercury (THg) and MeHg in rice plants were significantly correlated with Hg levels in soil, indicating soil is still an important source for both inorganic mercury (IHg) and MeHg in rice plants. The obvious discrepancy between the distribution patterns of THg and MeHg reflected different pathways of IHg and MeHg accumulation. Water soluble Hg may play more important role in MeHg accumulation in rice plants. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Qualitative Analysis of Polyphenols in Macroporous Resin Pretreated Pomegranate Husk Extract by HPLC-QTOF-MS.

    PubMed

    Abdulla, Rahima; Mansur, Sanawar; Lai, Haizhong; Ubul, Ablikim; Sun, Guangying; Huang, Guozheng; Aisa, Haji Akber

    2017-09-01

    Pomegranate (Punica granatum L.) husk is a traditional herbal medicine abundant in phenolic compounds and plays some roles in the treatment of oxidative stress, bacterial and viral infection, diabetes mellitus, and acute and chronic inflammation. Identification and determination of polyphenols in macroporous resin pretreated pomegranate husk extract by high performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (HPLC-QTOF-MS). The total polyphenols of pomegranate husk were prepared by ethanol extraction followed by pretreatment with HPD-300 macroporous resin. The polyphenolic compounds were qualitatively analysed by HPLC-QTOF-MS in negative electrospray ionisation (ESI) mode at different collision energy (CE) values. A total of 50 polyphenols were detected in the extract of pomegranate husk, including 35 hydrolysable tannins and 15 flavonoids with distinct retention time, fragmentation behaviours and characteristics, and the accurate mass-to-charge ratios at low, moderate and high CE values. Of these, we identified nine compounds for the first time in the pomegranate husk, including hexahydroxydiphenoyl-valoneoyl-glucoside (HHDP-valoneyl-glucoside), galloyl-O-punicalin, rutin, hyperoside, quercimeritrin, kaempferol-7-O-rhahmano-glucoside, luteolin-3'-O-arabinoside, luteolin-3'-O-glucoside, and luteolin-4'-O-glucoside. To validate the specificity and accuracy of mass spectrometry in the detection of polyphenols, as compared to the fragmentation pathways of granatin B in detail, including the HHDP-valoneyl- glucoside was first identified from pomegranate husk. The study provides evidence for the quality control and development of novel drugs based on polyphenols from the pomegranate husk. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  20. Identification of walnut husk (Juglans regia L.) volatiles and the behavioural response of the invasive Walnut Husk Fly, Rhagoletis completa Cresson.

    PubMed

    Sarles, Landry; Boullis, Antoine; Fassotte, Bérénice; Lognay, Georges; Verhaeghe, Agnès; Francis, Frédéric; Verheggen, François J

    2017-10-01

    Several European countries are important walnut (Juglans regia L.) producers. However, these countries must contend with the recent introduction of the Walnut Husk Fly, Rhagoletis completa Cresson (Diptera, Tephritidae), which is causing severe economic losses, especially in organic production. Because most Tephritid fruit flies use kairomones in their search for host plants, we hypothesise that this highly specialist species orients toward the volatile blend released by walnut husks. We collected, identified, and quantified the volatile organic chemicals (VOCs) released by walnut husks from the most commonly cultivated variety in France (Franquette). Then, the behavioural response of R. completa toward synthetic odour blends was recorded in dual choice assays conducted in net cages. A total of 26 VOCs were identified, with α-pinene, β-pinene, trans-linalool, eugenol, and tetradecane representing the major constituents. In the dual choice assay, male and female R. completa were strongly attracted to synthetic blend that included most of the identified husk VOCs. When searching for a host plant, R. completa use host fruit kairomones. The potential of these semiochemicals in monitoring and management of this quarantine pest is discussed. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  1. Comparison of raw and modified activated carbon and rice industry wastes for methylene blue sorption

    NASA Astrophysics Data System (ADS)

    Befani, Maria; Manariotis, Ioannis D.; Karapanagioti, Hrissi K.; Quintero, César E.

    2015-04-01

    In Argentina the average paddy rice production was 1.3x106 tn/year in the last decade. Entre Ríos province (E.R.) accounts for 60% of national milling, resulting in a significant accumulation of waste in the local environment; husk and ashes are used as fuel in drying grain plants. The use of rice wastes, as low-cost sorbents for the removal of synthetic dyes and other contaminants may be a sustainable option. The aim of this work is the investigation of the removal capacity of methylene blue (MB) from aqueous solutions using: (a) rice husk from a rice mill located in E.R. of size between 0.15 to 1.18 mm (RH2), (b) ash from rice husk burned at 800°C in oven for the grain drying unit of the rice mill (RHA800), and (c) biochar obtained from pyrolysis of RH2 material at 850°C (RHA4). Commercial activated carbon (AC), which is a porous material of high sorption capacity, was also used to compare its sorption capacity with the rice husk products. Furthermore, the incorporation of iron in the AC was studied using two different AC/Fe weight-by-weight ratios (AC-Fe and AC-0.5 Fe). The solution pH effect was studied in a range from 2 to 6.9. The maximal MB removal was achieved at pH of 6.8 to 6.9 for all materials studied, and at pH of 6.4 for AC. Kinetic experiments were conducted for a period of 48 h at pH 7 and C0 = 50 mg MB/L. Equilibrium was reached after 24 h and the adsorption capacity was 156, 104, 90, 79, 26, and 9 mg/g for AC, AC-Fe, AC-0.5 Fe, RHA4, RH2 and RHA800, respectively. The pseudo-second-order model expressed better the sorption kinetics of MB for all adsorbent materials. The AC-based materials presented better performance. The experimental data were fitted with the Freundlich and Langmuir isotherm models. The Langmuir model fits the data better in all cases. The maximum adsorption capacity was 238, 125, 92, 91, 46 and 9 mg/g for AC, AC-Fe, AC-0.5 Fe, RHA4, RH2 and RHA800, respectively. Agricultural wastes can be considered low-cost sorbents, but

  2. Effectiveness of Rice Agricultural Waste, Microbes and Wetland Plants in the Removal of Reactive Black-5 Azo Dye in Microcosm Constructed Wetlands.

    PubMed

    Saba, Beenish; Jabeen, Madeeha; Khalid, Azeem; Aziz, Irfan; Christy, Ann D

    2015-01-01

    Azo dyes are commonly generated as effluent pollutants by dye using industries, causing contamination of surface and ground water. Various strategies are employed to treat such wastewater; however, a multi-faceted treatment strategy could be more effective for complete removal of azo dyes from industrial effluent than any single treatment. In the present study, rice husk material was used as a substratum in two constructed wetlands (CWs) and augmented with microorganisms in the presence of wetland plants to effectively treat dye-polluted water. To evaluate the efficiency of each process the study was divided into three levels, i.e., adsorption of dye onto the substratum, phytoremediation within the CW and then bioremediation along with the previous two processes in the augmented CW. The adsorption process was helpful in removing 50% dye in presence of rice husk while 80% in presence of rice husk biocahr. Augmentation of microorganisms in CW systems has improved dye removal efficiency to 90%. Similarly presence of microorganisms enhanced removal of total nitrogen (68% 0 and Total phosphorus (75%). A significant improvement in plant growth was also observed by measuring plant height, number of leaves and leave area. These findings suggest the use of agricultural waste as part of a CW substratum can provide enhanced removal of textile dyes.

  3. Combined subcritical water and enzymatic hydrolysis for reducing sugar production from coconut husk

    NASA Astrophysics Data System (ADS)

    Muharja, Maktum; Junianti, Fitri; Nurtono, Tantular; Widjaja, Arief

    2017-05-01

    Coconut husk wastes are abundantly available in Indonesia. It has a potential to be used into alternative renewable energy sources such as hydrogen using enzymatic hydrolysis followed by a fermentation process. Unfortunately, enzymatic hydrolysis is hampered by the complex structure of lignocellulose, so the cellulose component is hard to degrade. In this study, Combined Subcritical Water (SCW) and enzymatic hydrolysis are applied to enhance fermentable, thereby reducing production of sugar from coconut husk. There were two steps in this study, the first step was coconut husk pretreated by SCW in batch reactor at 80 bar and 150-200°C for 60 minutes reaction time. Secondly, solid fraction from the results of SCW was hydrolyzed using the mixture of pure cellulose and xylanase enzymes. Analysis was conducted on untreated and SCW-treated by gravimetric assay, liquid fraction after SCW and solid fraction after enzymatic hydrolysis using DNS assay. The maximum yield of reducing sugar (including xylose, arabinose glucose, galactose, mannose) was 1.254 gr per 6 gr raw material, representing 53.95% of total sugar in coconut husk biomass which was obtained at 150°C 80 bar for 60 minutes reaction time of SCW-treated and 6 hour of enzymatic hydrolysis using mixture of pure cellulose and xylanase enzymes (18.6 U /gram of coconut husk).

  4. Olive husk: an alternative sorbent for removing heavy metals from aqueous streams.

    PubMed

    Volpe, Angela; Lopez, Antonio; Pagano, Michele

    2003-09-01

    Sorption properties of olive husk were investigated under equilibrium (batch tests) and dynamic (column tests) conditions in order to assess the possibility of using such a waste material for removing heavy metals from aqueous streams. Husk samples were contacted, at 25 degrees C, with aqueous solutions of nitric salts of Pb, Cd, Cu, and Zn. Sorption isotherms obtained from equilibrium data were fitted and interpreted by the Freundlich model. Metals-saturated husk samples resulting from column tests were air-dried and incinerated to simulate combustion in order to assess the fate of sorbed metals. The results demonstrated that, under both equilibrium and dynamic conditions, metal sorption capacity of the husk was in the sequence Pb>Cd>Cu>Zn. For all the metals, calculated Freundlich constants decreased by increasing initial metal concentration or decreasing solution pH. In dynamic tests, a significant reduction of sorption capacity was recorded (except for copper) when a metal was fed simultaneously to the others: Pb (77%); Cd (93%); Zn (68%). Combustion tests carried out on metals-saturated husk samples showed that the average losses of lead and cadmium, as volatile species, were always three to four times greater than the losses of copper and zinc, in both single-metal- and multimetal-saturated samples.

  5. Steam explosion pretreatment improved the biomethanization of coffee husks.

    PubMed

    Baêta, Bruno Eduardo Lobo; Cordeiro, Paulo Henrique de Miranda; Passos, Fabiana; Gurgel, Leandro Vinícius Alves; de Aquino, Sérgio Francisco; Fdz-Polanco, Fernando

    2017-08-31

    This study evaluated the potential of energy generation using a combined heat and power co-generation system (CHP) from biogas produced during the anaerobic digestion of coffee husks (CH) pretreated with steam explosion. Pretreatment conditions assessed were time (1, 5, 15 and 60min) and temperature (120, 180 and 210°C). Polysaccharides solubilisation and biogas production were not correlated. While pretreatment with severities higher than 4 resulted in a highest solubilisation of cellulose, hemicelluloses and lignin; however, furans concentration in those cases hindered biomass biodegradation. Considering a CHP, all pretreatment conditions were worthwhile when compared to non-pretreated CH. The best condition was 120°C for 60min, in which a 2.37 severity showed the highest methane yield (144.96NmLCH4gCOD(-1)) and electricity production (0.59kWhkgCH(-1)). However, even better results could be achieved using 120°C for only 5min, which would lead to a larger amount of CH daily processed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Antibiofilm activity of coconut (Cocos nucifera Linn.) husk fibre extract

    PubMed Central

    Viju, N.; Satheesh, S.; Vincent, S.G.P.

    2012-01-01

    In this study, antibiofilm activity of coconut husk extract (CHE) was tested by various assays in the laboratory. The effects of CHE on extracellular polymeric substance (EPS) production, hydrophobicity and adhesion ability of Pseudomonas sp., Alteromonas sp. and Gallionella sp. and the antimicrobial activity of the extract against these bacteria were assessed. CHE was found to possess antibacterial activity against all the bacterial strains and affected the EPS production. The CHE affected the growth of the biofilm-forming bacteria in a culture medium. The hydrophobicity of the bacterial cells was also changed due to the CHE treatment. The active compound of the CHE was characterised by thin-layer chromatography (TLC), high performance liquid chromatography (HPLC) and fourier transform infrared (FT-IR) analysis. HPLC spectrum showed a single peak and the FT-IR spectrum indicated the presence of an OH-group-containing compound in the extract. In conclusion the CHE could be used as a source for the isolation of antifouling compounds. PMID:23961225

  7. Antimalarial Activity of Cocos nucifera Husk Fibre: Further Studies

    PubMed Central

    Adebayo, J. O.; Balogun, E. A.; Malomo, S. O.; Soladoye, A. O.; Olatunji, L. A.; Kolawole, O. M.; Oguntoye, O. S.; Babatunde, A. S.; Akinola, O. B.; Aguiar, A. C. C.; Andrade, I. M.; Souza, N. B.; Krettli, A. U.

    2013-01-01

    In this study, the antimalarial and toxicity potentials of husk fibre extracts of five Nigerian varieties of Cocos nucifera were evaluated in vitro. The only active extract fraction, West African Tall (WAT) ethyl acetate extract fraction, was then evaluated for its phytochemical constituents, antimalarial and toxicity potentials at varying doses (31.25–500 mg/kg body weight) using various organ function indices. The results revealed that WAT ethyl acetate extract fraction (WATEAEF) contained alkaloids, tannins, and flavonoids and was active against Plasmodium falciparum W2 strain maintained in continuous culture, with a selectivity index of 30.3. The same extract fraction was active in vivo against Plasmodium berghei NK65, causing more than 50% reduction in parasitaemia on days 4 and 6 after inoculation at various doses administered. WATEAEF did not significantly alter (P > 0.05) function indices of the liver and cardiovascular system at all doses administered but significantly increased (P < 0.05) plasma creatinine concentration at 250 and 500 mg/Kg body weight compared to controls. The results of this study suggest that WATEAEF possesses antimalarial activity and may not adversely affect normal liver function nor predispose subjects to cardiovascular diseases but may impair normal kidney function at higher doses. Further studies are underway to isolate the active principles. PMID:23983800

  8. Two new isoxazolines from the husks of Xanthoceras sorbifolia Bunge.

    PubMed

    Ge, Hui-Qi; Wan, Guo-Sheng; Wang, Da; Wu, Ji-Ming; Sun, Bo-Hang; Wu, Li-Jun; Gao, Hui-Yuan

    2016-08-01

    Two new isoxazoline compounds, 1-oxa-2-azaspiro[4.5]dec-2-ene-8β-ol (1) and 1-oxa-2-azaspiro[4.5]dec-2-ene-8α-ol (2), were isolated from the husks of fruits of Xanthoceras sorbifolia Bunge and their structures were determined by spectroscopic analyses, including X-ray crystallography, HRESI-MS, UV, IR, and 1D and 2D NMR (HSQC, HMBC, NOESY) methods. Neither compound showed significant inhibitory effects on butyrylcholinesterase (BuchE) and acetylcholinesterase (AChE), nor the selected tumor cells growth. Based on an online activity prediction program (PASS ONLINE), the structures with isoxazoline skeletons were found to show potential anti-asthmatic (AM) and anti-anaphylaxis (AP) activities; moreover, compounds 1 and 2 were predicted to possess high affinities for many enzymes involved in AM and AP according to the RCSB Protein Data Bank. High-affinity binding to phosphodiesterase IV (PDE-4), an important inflammatory modulator in asthma, was demonstrated experimentally, beside that, the predicted structures based on compounds 1 and 2 were analyzed for PDE-4 interactions using the molecular docking methodology of Discovery Studio 3.0 (DS 3.0). The predicted structure 2A-6 exhibited much higher affinity and stability of PDE-4 binding than the clinical PDE-4 inhibitor rolipram.

  9. 76 FR 78231 - Notice of Decision To Authorize the Importation of Fresh Cape Gooseberry Fruit With Husks From Chile

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-16

    ... Gooseberry Fruit With Husks From Chile AGENCY: Animal and Plant Health Inspection Service, USDA. ACTION... continental United States of fresh Cape gooseberry fruit (Physalis peruviana L.) with husks from Chile. Based... weeds via the importation of fresh Cape gooseberry fruit from Chile. DATES: Effective Date: December 16...

  10. Rice ( Oryza) hemoglobins

    PubMed Central

    Arredondo-Peter, Raúl; Moran, Jose F.; Sarath, Gautam

    2014-01-01

    Hemoglobins (Hbs) corresponding to non-symbiotic (nsHb) and truncated (tHb) Hbs have been identified in rice ( Oryza). This review discusses the major findings from the current studies on rice Hbs. At the molecular level, a family of the nshb genes, consisting of hb1, hb2, hb3, hb4 and hb5, and a single copy of the thb gene exist in Oryza sativa var. indica and O. sativa var. japonica, Hb transcripts coexist in rice organs and Hb polypeptides exist in rice embryonic and vegetative organs and in the cytoplasm of differentiating cells. At the structural level, the crystal structure of rice Hb1 has been elucidated, and the structures of the other rice Hbs have been modeled. Kinetic analysis indicated that rice Hb1 and 2, and possibly rice Hb3 and 4, exhibit a very high affinity for O 2, whereas rice Hb5 and tHb possibly exhibit a low to moderate affinity for O 2. Based on the accumulated information on the properties of rice Hbs and data from the analysis of other plant and non-plant Hbs, it is likely that Hbs play a variety of roles in rice organs, including O 2-transport, O 2-sensing, NO-scavenging and redox-signaling. From an evolutionary perspective, an outline for the evolution of rice Hbs is available. Rice nshb and thb genes vertically evolved through different lineages, rice nsHbs evolved into clade I and clade II lineages and rice nshbs and thbs evolved under the effect of neutral selection. This review also reveals lacunae in our ability to completely understand rice Hbs. Primary lacunae are the absence of experimental information about the precise functions of rice Hbs, the properties of modeled rice Hbs and the cis-elements and trans-acting factors that regulate the expression of rice hb genes, and the partial understanding of the evolution of rice Hbs. PMID:25653837

  11. Rice ( Oryza) hemoglobins.

    PubMed

    Arredondo-Peter, Raúl; Moran, Jose F; Sarath, Gautam

    2014-01-01

    Hemoglobins (Hbs) corresponding to non-symbiotic (nsHb) and truncated (tHb) Hbs have been identified in rice ( Oryza). This review discusses the major findings from the current studies on rice Hbs. At the molecular level, a family of the nshb genes, consisting of hb1, hb2, hb3, hb4 and hb5, and a single copy of the thb gene exist in Oryza sativa var. indica and O. sativa var. japonica, Hb transcripts coexist in rice organs and Hb polypeptides exist in rice embryonic and vegetative organs and in the cytoplasm of differentiating cells. At the structural level, the crystal structure of rice Hb1 has been elucidated, and the structures of the other rice Hbs have been modeled. Kinetic analysis indicated that rice Hb1 and 2, and possibly rice Hb3 and 4, exhibit a very high affinity for O 2, whereas rice Hb5 and tHb possibly exhibit a low to moderate affinity for O 2. Based on the accumulated information on the properties of rice Hbs and data from the analysis of other plant and non-plant Hbs, it is likely that Hbs play a variety of roles in rice organs, including O 2-transport, O 2-sensing, NO-scavenging and redox-signaling. From an evolutionary perspective, an outline for the evolution of rice Hbs is available. Rice nshb and thb genes vertically evolved through different lineages, rice nsHbs evolved into clade I and clade II lineages and rice nshbs and thbs evolved under the effect of neutral selection. This review also reveals lacunae in our ability to completely understand rice Hbs. Primary lacunae are the absence of experimental information about the precise functions of rice Hbs, the properties of modeled rice Hbs and the cis-elements and trans-acting factors that regulate the expression of rice hb genes, and the partial understanding of the evolution of rice Hbs.

  12. Dissipation of chlorpyrifos and residue analysis in rice, soil and water under paddy field conditions.

    PubMed

    Zhang, Xiao; Shen, Yan; Yu, Xiang-yang; Liu, Xian-jin

    2012-04-01

    The analytical method for the residues of chlorpyrifos in rice plants, water and soil was developed and dissipation of chlorpyrifos under field conditions was studied. The limit of detection (LOD) of chlorpyrifos was 0.006 mg kg(-1) and the limit of quantification (LOQ) was found to be 0.04 mg kg(-1) in rice plant (water) and 0.02 mg kg(-1) in the other substrates, respectively. The results showed that the initial residues of chlorpyrifos in Nanjing and Guangxi were 4.99 and 6.05 mg kg(-1) (rice plant), 1.35 and 1.58 mg kg(-1) (water) and 0.51 and 0.63 mg kg(-1) (soil), respectively. The half-lives of chlorpyrifos in rice plant, water and soil from Nanjing were 4.28, 0.58 and 1.35 day, respectively, and the half-lives of those from Guangxi were 3.86, 0.52 and 1.21 day, respectively. The husked rice, rice hull and straw samples were found to contain chlorpyrifos well below the maximum residue limit (MRL) following the recommended dosage, the residues of chlorpyrifos in soil were undetectable under all application levels and frequencies after 28 day of applications.

  13. Using cultural-historical activity theory to analyze social service practices evolving from the Norwegian HUSK projects.

    PubMed

    Foot, Kirsten

    2015-01-01

    The HUSK projects catalyzed innovation in the practices of providing social services that could yield useful insights both within and outside of Norway if analyzed in these two ways: (a) retrospective analysis of the development of individual HUSK projects in light of their cultural-historical contexts, and (b) comparative analysis of the efforts to advance multi-sector collaboration in some of the HUSK projects. Such analyses require a practice-based research approach that takes into account culture and history. In this article the author explains how cultural-historical activity theory provides such an approach, illustrated via several HUSK cases. The author suggests five questions for future analyses of the HUSK projects and argues that insights gleaned from such analyses could contribute significantly to research on-and the provision of-social services.

  14. Evaluation of untreated coffee husks as potential biosorbents for treatment of dye contaminated waters.

    PubMed

    Oliveira, Leandro S; Franca, Adriana S; Alves, Thiago M; Rocha, Sônia D F

    2008-07-15

    The objective of this work was to propose an alternative use for coffee husks (CH), a coffee processing residue, as untreated sorbents for the removal of methylene blue (MB) from aqueous solutions. The effects of solution temperature, pH, biosorbent dosage and contact time on MB removal were investigated. The experimental adsorption equilibrium data were fitted to both Langmuir and Freundlich adsorption models. The biosorption kinetics was determined by fitting first and second-order kinetic models to the experimental data, with the second-order model providing the best description of MB adsorption onto coffee husks. pH variations did not present a significant effect on MB removal. Evaluation of thermodynamics parameters indicated that the adsorption is spontaneous and endothermic. The experimental data obtained in the present study demonstrated coffee husks to be suitable candidates for use as biosorbents in the removal of cationic dyes.

  15. A study on biocomposite from local balinese areca catechu l. husk fibers as reinforced material

    NASA Astrophysics Data System (ADS)

    Kencanawati, C. I. P. K.; Suardana, N. P. G.; Sugita, I. K. G.; Suyasa, I. W. B.

    2017-05-01

    Untapped areca catechu l. husk fibers optimally can cause pollution to the environment. Therefore it is necessary to learn the characteristics of local balinese areca catechu l. husk fibers, such as physical, chemical, morphological, and mechanical. AHF testing the tensile strength with a single pull fiber test in accordance with ASTM D 3379 in the amount of 146-152 MPa. While the observation of the physical properties, of local balinese areca catechu l. husk fibers have a diameter and length variations of each 250-540 μm and 9.24 to 55.20 mm, with an aspect ratio of between 31.43 to 102.22, density ranges between 0:48 - 0.74 kg / cm3, absorption lower water (90-150%) when compared to AHF grows in other areas. From this study it appears that local Bali AHF can be used as reinforcement in composite replacement for synthetic fibers.

  16. Antimicrobial and antiviral activities of polyphenolics from Cocos nucifera Linn. (Palmae) husk fiber extract.

    PubMed

    Esquenazi, Daniele; Wigg, Marcia D; Miranda, Mônica M F S; Rodrigues, Hugo M; Tostes, João B F; Rozental, Sonia; da Silva, Antonio J R; Alviano, Celuta S

    2002-12-01

    The decoction of Cocos nucifera L. husk fiber has been used in northeastern Brazil traditional medicine for treatment of diarrhea and arthritis. Water extract obtained from coconut husk fiber and fractions from adsorption chromatography revealed antimicrobial activity against Staphylococcus aureus. The crude extract and one of the fractions rich in catechin also showed inhibitory activity against acyclovir-resistant herpes simplex virus type 1 (HSV-1-ACVr). All fractions were inactive against the fungi Candida albicans, Fonsecaea pedrosoi and Cryptococcus neoformans. Catechin and epicatechin together with condensed tannins (B-type procyanidins) were demonstrated to be the components of the water extract.

  17. The effects of biochars from rice residue on the formation of iron plaque and the accumulation of Cd, Zn, Pb, As in rice (Oryza sativa L.) seedlings.

    PubMed

    Zheng, Rui-Lun; Cai, Chao; Liang, Jian-Hong; Huang, Qing; Chen, Zheng; Huang, Yi-Zong; Arp, Hans Peter H; Sun, Guo-Xin

    2012-10-01

    A historically multi-metal contaminated soil was amended with biochars produced from different parts of rice plants (straw, husk and bran) to investigate how biochar can influence the mobility of Cd, Zn, Pb and As in rice seedlings (Oryza sativa L.). Rice shoot concentrations of Cd, Zn and Pb decreased by up to 98%, 83% and 72%, respectively, due to biochar amendment, though that of As increased by up to 327%. Biochar amendments significantly decreased pore water concentrations (C(pw)) of Cd and Zn and increased that of As. For Pb it depended on the amendment. Porewater pH, dissolved organic carbon, dissolved phosphorus, silicon in pore water and iron plaque formation on root surfaces all increased significantly after the amendments. The proportions of Cd and Pb in iron plaque increased by factors 1.8-5.7 and 1.4-2.8, respectively; no increase was observed for As and Zn. Straw-char application significantly and noticeably decreased the plant transfer coefficients of Cd and Pb. This study, the first to investigate changes in metal mobility and iron plaque formation in rice plants due to amending a historically contaminated soil with biochar, indicates that biochar has a potential to decrease Cd, Zn and Pb accumulations in rice shoot but increase that of As. The main cause is likely biochar decreasing the C(pw) of Cd and Zn, increasing the C(pw) of As, and increasing the iron plaque blocking capacity for Cd and Pb.

  18. Distribution and translocation of selenium from soil to grain and its speciation in paddy rice (Oryza sativa L.).

    PubMed

    Sun, Guo-Xin; Liu, Xiao; Williams, Paul N; Zhu, Yong-Guan

    2010-09-01

    Selenium, an essential micronutrient for humans, is insufficient in dietary intake for millions of people worldwide. Rice as the most popular staple food in the world is one of the dominant selenium (Se) sources for people. The distribution and translocation of Se from soil to grain were investigated in a Se-rich environment in this study. The Se levels in soils ranged widely from 0.5 to 47.7 mg kg(-1). Selenium concentration in rice bran was 1.94 times higher than that in corresponding polished rice. The total Se concentrations in the rice fractions were in the following order: straw>bran>whole grain>polished rice>husk. Significant linear relationships between different rice fractions were observed with each other, and Se in the soil has a linear relationship with different rice fractions as well. Se concentration in rice can easily be predicted by soil Se concentrations or any rice fractions and vice versa according to their linear relationships. In all rice samples for Se speciation, SeMet was the major Se species, followed by MeSeCys and SeCys. The average percentage for SeMet (82.9%) and MeSeCys (6.2%) was similar in the range of total Se from 2.2 to 8.4 mg kg(-1) tested. The percentage of SeCys decreased from 6.3 to 2.8%, although its concentration elevated with the increase in total Se in rice. This could be due to the fact that SeCys is the precursor for the formation of other organic Se compounds. The information obtained may have considerable significance for assessing translocation and accumulation of Se in plant.

  19. Evaluation of the radioactive Cs concentration in brown rice based on the K nutritional status of shoots.

    PubMed

    Sekimoto, Hitoshi; Yamada, Takashi; Hotsuki, Tomoe; Fujiwara, Toru; Mimura, Tetsuro; Matsuzaki, Akio

    2014-01-01

    The radioactive cesium ((134,137)Cs) concentration in brown rice is correlated with that in the straw/husk. The distribution of (134,137)Cs, resembles that of potassium (K), a homologous element of Cs, in the rice plant body. The relative isotopic abundance of (40)K is 0.0117 %; thus, 1 g K contains 30.4 Bq ⁴⁰K, and the mass of 4,000 Bq (40)K is 0.0154 g, indicating that the K concentration can be calculated from (40)K concentration. We examined if the radioactive Cs concentration in brown rice can be estimated from (40)K concentrations in straw, and especially might be predicted from the (40)K:(134,137)Cs ratio in straw. We determined the concentrations of (40)K and radioactive Cs in straw and brown rice, and found a strong correlated-equation (y = 72.922 x(-0.759); r = 0.907) between the radioactive Cs concentration in brown rice and the ⁴⁰K:(134,137)Cs ratio in straw. The estimated-radioactive Cs concentration in brown rice can be as much as double, depending on the K nutritional status changing the ⁴⁰K:(134,137)Cs ratio in straw. We herein propose a nutritional diagnosis that radioactive Cs concentrations in brown rice can be predicted from the ⁴⁰K:(134,137)Cs ratio in shoots.

  20. Optimalization of silicon extraction from husk ashes by excessive magnesium addition on increasing rate of temperature reduction

    NASA Astrophysics Data System (ADS)

    Sintha, I.; Dahrul, M.; Ismawati, S. S.; Kurniati, M.; Irmansyah; Irzaman

    2017-05-01

    The Silicon can be extracted from rice husk ash by reducing silica with magnesium. In this study the use of Magnesium and Silica was 49:60 with various rate of increase in the reduction temperature (1 °C/minutes, 3 °C/minutes, and 5°C/minutes). It was done in order to obtain silicon with a higher purity than previous studies. The results of EDX showed that the purity silicon with the increase rate of 1 °C/minutes and 5 °C/minutes were 1.78% and 29.39%, respectively. Then, silicon was not formed by increasing rate of 3 °C/minutes. Moreover, XRD results of the samples by using the increase rate of 1 °C/minutes and 5 °C/minutes showed that the pattern correspond to Silicon while the sample with increase rate of 3 °C/min corresponds to Silica. The FTIR spectra indicate the presence of stretching vibration an harmonic for functional groups of Si-O-Si with spring constant for the increase rate of 1 °C/minutes, 3 °C/minutes, and 5 °C/minutes respectively were 977.23 N/m, 1003 N/m, and 982.3 N/m. FTIR result was consistent with EDX and XRD result proving by the existence of Si-O-Si functional group which showed the purity silicon produced was not optimum and presence of OH-functional group indicate that sample contained water

  1. Coffee husk mulch on soil erosion and runoff: experiences under rainfall simulation experiment

    NASA Astrophysics Data System (ADS)

    Moreno-Ramón, H.; Quizembe, S. J.; Ibáñez-Asensio, S.

    2014-05-01

    The high erosion rates found in the agriculture land make valuable the use of mulches to control the soil and water losses. Coffee husk (Coffee canephora var. robusta) can be one of those mulches. This paper evaluates how to apply the mulch in order to obtain, with the same doses, the best effectiveness. An experimental factorial design 4 × 3 × 2 with two replicates was designed in a greenhouse with a total amount of 48 treatments. All the samples were deposited in trays of 0.51 m2 and applied a simulated rain of 122 mm h-1 during 21 min. The factors examined were: four soil classes; three treatments: buried (B), surface (S) and non-residue (C), and the presence (WC) or absence (WOC) of the soil surface crusting. The coffee husk residue (S and B treatments) reduced runoff by 10.2% and 46% respectively, soil losses by 78.3% and 88.7% and sediment concentration by 77% and 84.4%. The infiltration rate increased on average by 104% and 167%, and time to runoff by 1.58 and 2.07 min respectively. The coffee husk mulch (S and B) avoided the influence of crust. Coffee husk is an efficient mulch to reduce the soil and water losses.

  2. Effect of chickpea husk dietary supplementation on blood and cecal parameters in rats.

    PubMed

    Myint, Htun; Kishi, Hiroyuki; Koike, Satoshi; Kobayashi, Yasuo

    2017-02-01

    Chickpea husk was functionally evaluated for antioxidant status, blood parameters, cecal fermentation and microbial profiles in rats. Fifteen male rats (5 weeks of age) were divided into three groups; they were individually housed and fed one of the following diets for 3 weeks: purified diet containing 5% cellulose (Cellulose), an identical diet in which cellulose was replaced by corn starch (Starch) or by chickpea husk (Chick). Rats were sacrificed to obtain blood and cecal digesta samples. Chickpea husk contained high polyphenolic content and significant superoxide dismutase and 2,2-diphenyl-picrylhydrazyl scavenging activities. In a feeding experiment, Chick showed lowered cholesterol levels and improved antioxidant activity represented by reduced thiobarbituric acid reactive substances in blood. Chick showed increased cecal levels of total short chain fatty acids and butyrate, leading to a lower pH. Chick presented with lowered cecal indole and skatole concentrations, as did Cellulose. Cecal bacterial changes were notable in Chick, evidenced by differences in denaturing gradient gel electrophoresis banding patterns. However, representative bacteria quantified by real-time PCR assay did not support this bacterial change. These results indicate that chickpea husk feeding can improve the antioxidative status of rats through its polyphenolic components and modulate the hindgut environment by its fibrous components.

  3. Rheological Characterization of Isabgol Husk, Gum Katira Hydrocolloids, and Their Blends.

    PubMed

    Sharma, Vipin Kumar; Mazumder, Bhaskar; Nautiyal, Vinod

    2014-01-01

    The rheological parameters of Isabgol husk, gum katira, and their blends were determined in different media such as distilled water, 0.1 N HCl, and phosphate buffer (pH 7.4). The blend properties of Isabgol husk and gum katira were measured for four different percentage compositions in order to understand their compatibility in dispersion form such as 00 : 100, 25 : 50, 50 : 50, 75 : 25, and 100 : 00 in the gel strength of 1 mass%. The miscibility of blends was determined by calculating Isabgol husk-gum katira interaction parameters by Krigbaum and Wall equation. Other rheological properties were analyzed by Bingham, Power, Casson, Casson chocolate, and IPC paste analysis. The study revealed that the power flow index "p" was less than "1" in all concentrations of Isabgol husk, gum katira, and their blends dispersions indicating the shear-thinning (pseudoplastic) behavior. All blends followed pseudoplastic behavior at thermal conditions as 298.15, 313.15, and 333.15°K and in dispersion media such as distilled water, 0.1 N HCl, and phosphate buffer (pH 7.4). Moreover, the study indicated the applicability of these blends in the development of drug delivery systems and in industries, for example, ice-cream, paste, nutraceutical, and so forth.

  4. Rheological Characterization of Isabgol Husk, Gum Katira Hydrocolloids, and Their Blends

    PubMed Central

    Sharma, Vipin Kumar; Mazumder, Bhaskar; Nautiyal, Vinod

    2014-01-01

    The rheological parameters of Isabgol husk, gum katira, and their blends were determined in different media such as distilled water, 0.1 N HCl, and phosphate buffer (pH 7.4). The blend properties of Isabgol husk and gum katira were measured for four different percentage compositions in order to understand their compatibility in dispersion form such as 00 : 100, 25 : 50, 50 : 50, 75 : 25, and 100 : 00 in the gel strength of 1 mass%. The miscibility of blends was determined by calculating Isabgol husk-gum katira interaction parameters by Krigbaum and Wall equation. Other rheological properties were analyzed by Bingham, Power, Casson, Casson chocolate, and IPC paste analysis. The study revealed that the power flow index “p” was less than “1” in all concentrations of Isabgol husk, gum katira, and their blends dispersions indicating the shear-thinning (pseudoplastic) behavior. All blends followed pseudoplastic behavior at thermal conditions as 298.15, 313.15, and 333.15°K and in dispersion media such as distilled water, 0.1 N HCl, and phosphate buffer (pH 7.4). Moreover, the study indicated the applicability of these blends in the development of drug delivery systems and in industries, for example, ice-cream, paste, nutraceutical, and so forth. PMID:26904636

  5. Pretreatment with ammonia water for enzymatic hydrolysis of corn husk, bagasse, and switchgrass.

    PubMed

    Kurakake, M; Kisaka, W; Ouchi, K; Komaki, T

    2001-03-01

    Bagasse, corn husk, and switchgrass were pretreated with ammonia water to enhance enzymatic hydrolysis. The sample (2 g) was mixed with 1-6 mL ammonia water (25-28% ammonia) and autoclaved at 120 degreesC for 20 min. After treatment, the product was vacuum-dried to remove ammonia gas. The dried solid could be used immediately in the enzymatic hydrolysis without washing. The enzymatic hydrolysis was effectively improved with more than 0.5 and 1 mL ammonia water/g for corn husk and bagasse, respectively. In bagasse, glucose, xylose, and xylobiose were the main products. The adsorption of CMCase and xylanase was related to the initial rate of enzymatic hydrolysis. In corn husks, arabinoxylan extracted by pretreatment was substantially unhydrolyzed because of the high ratio of arabinose to xylose (0.6). The carbohydrate yields from cellulose and hemicellulose were 72.9% and 82.4% in bagasse, and 86.2% and 91.9% in corn husk, respectively. The ammonia/water pretreatment also benefited from switchgrass (Miscanthus sinensis and Solidago altissima L.) hydrolysis.

  6. Bio-softening of mature coconut husk for facile coir recovery.

    PubMed

    Suganya, D S; Pradeep, S; Jayapriya, J; Subramanian, S

    2007-06-01

    Bio-softening of the mature coconut husk using Basidiomyceteous fungi was attempted to recover the soft and whiter fibers. The process was faster and more efficient in degrading lignin and toxic phenolics. Phanerochaete chrysosporium, Pleurotus eryngii and Ceriporiopsis subvermispora were found to degrade lignin efficiently without any appreciable loss of cellulose, yielding good quality fiber ideal for dyeing.

  7. Evaluation of the Association Metformin: Plantago ovata Husk in Diabetic Rabbits

    PubMed Central

    Díez-Láiz, Raquel; García-Vieitez, Juan J.; Diez-Liébana, M. José; Sierra-Vega, Matilde; Sahagún-Prieto, Ana M.; Calle-Pardo, Ángela P.; Fernández-Martínez, Nélida

    2015-01-01

    In this experimental study we have investigated whether the inclusion of the dietary fiber Plantago ovata husk could be recommended as coadjuvant in treatments with oral hypoglycemic drugs. We evaluated the use of Plantago ovata husk-metformin association in diabetic rabbits by determining its effects on glucose and insulin concentrations. Six groups of 6 rabbits were used. Groups 1 to 3 were fed with standard chow and groups 4 to 6 with chow supplemented with Plantago ovata husk (3.5 mg/kg/day). Two groups (numbers 1 and 4) were used as controls (receiving standard or supplemented chow), two groups (numbers 2 and 5) received metformin orally, and the other two (numbers 3 and 6) were treated orally with metformin and psyllium. Plasma glucose concentrations were lower in groups fed with fiber-supplemented chow whereas insulin levels showed important interindividual variations. Glucose pharmacokinetics parameters showed significant differences in Cmax and tmax in relation to fiber intake. Insulin pharmacokinetics parameters after treatment with oral metformin showed an important increase in Cmax, AUC, and tmax in animals fed with fiber. We conclude that Plantago ovata husk intake can contribute to the oral antihyperglycemic treatment of type 2 diabetes. PMID:26576433

  8. Rice Production and Marketing.

    ERIC Educational Resources Information Center

    Briers, Gary; Lee, Jasper S.

    This guide contains lesson plans for use in secondary programs of agricultural education in geographical areas in which rice is produced. Six units and 13 problem areas are organized into teaching plans that cover the broad nature of rice production. The six units are: (1) determining the importance and history of rice production; (2) determining…

  9. Antimalarial and antiplasmodial activity of husk extract and fractions of Zea mays.

    PubMed

    Okokon, Jude E; Antia, Bassey S; Mohanakrishnan, Dinesh; Sahal, Dinkar

    2017-12-01

    Zea mays L. (Poacae) husk decoctions are traditionally used in the treatment of malaria by various tribes in Nigeria. To assess the antimalarial and antiplasmodial potentials of the husk extract and fractions on malaria parasites using in vivo and in vitro models. The ethanol husk extract and fractions (187-748 mg/kg, p.o.) of Zea mays were investigated for antimalarial activity against Plasmodium berghei using rodent (mice) malaria models and in vitro activity against chloroquine sensitive (Pf 3D7) and resistant (Pf INDO) strains of Plasmodium falciparum using the SRBR green assay method. Median lethal dose and cytotoxic activities against HeLa and HEKS cells were also carried out. The GCMS analysis of the most active fraction was carried out. The husk extract (187-748 mg/kg, p.o.) with LD50 of 1874.83 mg/kg was found to exert significant (p < 0.05-0.001) antimalarial activity against P. berghei infection in suppressive, prophylactive and curative tests. The crude extract and fractions also exerted prominent activity against both chloroquine sensitive (Pf 3D7) and resistant (Pf INDO) strains of P. falciparum with the ethyl acetate fraction exerting the highest activity with IC50 values of 9.31 ± 0.46 μg/mL (Pf 3D7) and 3.69 ± 0.66 μg/mL (Pf INDO). The crude extract and fractions were not cytotoxic to the two cell lines tested with IC50 values of >100 μg/mL against both HeLa and HEKS cell lines. These results suggest that the husk extract/fractions of Zea mays possesses antimalarial and antiplasmodial activities and these justify its use in ethnomedicine to treat malaria infections.

  10. Prevalence of respiratory symptoms and disorders among rice mill workers in India.

    PubMed

    Ghosh, Tirthankar; Gangopadhyay, Somnath; Das, Banibrata

    2014-05-01

    Lung function tests have become an integral part of assessment of pulmonary disease. Diseases of the respiratory system induced by occupational dusts are influenced by the duration of exposure. The aim of the study is to investigate the impairment of lung function and prevalence of respiratory symptoms among the rice mill workers. A total of 120 rice mill workers from three districts of Karnataka were included in this study. Fifty urban dwellers from the same socio-economic level were selected as controls. The study included clinical examination, assessment of respiratory symptoms, pulmonary function test, measurement of peak expiratory flow rate, absolute eosinophil count, ESR estimation, total IgE estimation and radiographic test. The present study has shown that the rice mill workers complained of several types of respiratory disorders like phlegm (40.8 %), dyspnea (44.2 %), chest tightness (26.7 %), cough (21.7 %), and nose irritation (27.5 %). Rice mill workers exposed to dust presented significantly (p < 0.05) lower levels of FVC (3.44 ± 0.11), FEV1 (2.73 ± 0.15) and PEFR (304.95 ± 28.79) than the controls. The rice mill workers are having significantly higher absolute eosinophil counts, total IgE and ESR than control groups. The hematological findings suggest that the harmful effects may be linked to both non-specific irritation and allergic responses to rice husk dust among rice mill workers. Dust exposure in the working environment affects the lung function values and increased the respiratory symptoms among the rice mill workers.

  11. Sustainable reuse of rice residues as feedstocks in vermicomposting for organic fertilizer production.

    PubMed

    Shak, Katrina Pui Yee; Wu, Ta Yeong; Lim, Su Lin; Lee, Chieh Ai

    2014-01-01

    Over the past decade, rice (Oryza sativa or Oryza glaberrima) cultivation has increased in many rice-growing countries due to the increasing export demand and population growth and led to a copious amount of rice residues, consisting mainly of rice straw (RS) and rice husk (RH), being generated during and after harvesting. In this study, Eudrilus eugeniae was used to decompose rice residues alone and rice residues amended with cow dung (CD) for bio-transformation of wastes into organic fertilizer. Generally, the final vermicomposts showed increases in macronutrients, namely, calcium (11.4-34.2%), magnesium (1.3-40.8%), phosphorus (1.2-57.3%), and potassium (1.1-345.6%) and a decrease in C/N ratio (26.8-80.0%) as well as increases in heavy metal content for iron (17-108%), copper (14-120%), and manganese (6-60%) after 60 days of vermicomposting. RS as a feedstock was observed to support healthier growth and reproduction of earthworms as compared to RH, with maximum adult worm biomass of 0.66 g/worm (RS) at 60 days, 31 cocoons (1RS:2CD), and 23 hatchlings (1RS:1CD). Vermicomposting of RS yielded better results than RH among all of the treatments investigated. RS that was mixed with two parts of CD (1RS:2CD) showed the best combination of nutrient results as well as the growth of E. eugeniae. In conclusion, vermicomposting could be used as a green technology to bio-convert rice residues into nutrient-rich organic fertilizers if the residues are mixed with CD in the appropriate ratio.

  12. Transgenic rice expressing the cry2AX1 gene confers resistance to multiple lepidopteran pests.

    PubMed

    Chakraborty, M; Reddy, P Sairam; Mustafa, G; Rajesh, G; Narasu, V M Laxmi; Udayasuriyan, V; Rana, Debashis

    2016-10-01

    A chimeric Bacillus thuringiensis toxin (Bt) gene, cry2AX1was cloned in a bi-selectable marker free binary vector construct. The cry2AX1 gene, driven by the Chrysanthemum rbcS1 promoter, was introduced into JK1044R, the restorer line (Oryza sativa L. ssp. Indica) of a notified commercially grown rice hybrid in India, by Agrobacterium-mediated transformation. Its effect against two major lepidopteran insect pests viz., yellow stem borer (YSB) Scirpophaga incertulas, rice leaf folder (RLF) Cnaphalocrocis medinalis and one minor insect pest, oriental army worm (OAW) Mythimna separata was demonstrated through bioassays of transgenic rice plants under laboratory and greenhouse conditions. The rbcS1 promoter with chloroplast signal peptide was used to avoid Cry2AX1 protein expression in rice seed endosperm tissue. A total of 37 independent transformants were generated, of which after preliminary molecular characterization and YSB bioassay screening, five events were selected for their protein expression and bioefficacy against all three rice insect. One elite transgenic rice line, BtE15, was identified with Cry2AX1 expression ranging from 0.68 to 1.34 µg g(-1) leaf fresh weight and with 80-92 % levels of resistance against rice pests at the vegetative and reproductive stages. Increase in Cry2AX1 protein concentration was also observed with crop maturity. The Cry2AX1protein concentration in the de-husked seeds was negligible (as low as 2.7-3.6 ng g(-1)). These results indicate the potential application of cry2AX1 gene in rice for protection against YSB, RLF and OAW.

  13. Silicon improves rice grain yield and photosynthesis specifically when supplied during the reproductive growth stage.

    PubMed

    Lavinsky, Alyne O; Detmann, Kelly C; Reis, Josimar V; Ávila, Rodrigo T; Sanglard, Matheus L; Pereira, Lucas F; Sanglard, Lílian M V P; Rodrigues, Fabrício A; Araújo, Wagner L; DaMatta, Fábio M

    2016-11-01

    Silicon (Si) has been recognized as a beneficial element to improve rice (Oryza sativa L.) grain yield. Despite some evidence suggesting that this positive effect is observed when Si is supplied along the reproductive growth stage (from panicle initiation to heading), it remains unclear whether its supplementation during distinct growth phases can differentially impact physiological aspects of rice and its yield and the underlying mechanisms. Here, we investigated the effects of additions/removals of Si at different growth stages and their impacts on rice yield components, photosynthetic performance, and expression of genes (Lsi1, Lsi2 and Lsi6) involved in Si distribution within rice shoots. Positive effects of Si on rice production and photosynthesis were manifested when it was specifically supplied during the reproductive growth stage, as demonstrated by: (1) a high crop yield associated with higher grain number and higher 1000-grain weight, whereas the leaf area and whole-plant biomass remained unchanged; (2) an increased sink strength which, in turn, exerted a feed-forward effect on photosynthesis that was coupled with increases in both stomatal conductance and biochemical capacity to fix CO2; (3) higher Si amounts in the developing panicles (and grain husks) in good agreement with a remarkable up-regulation of Lsi6 (and to a lesser extent Lsi1). We suggest that proper levels of Si in these reproductive structures seem to play an as yet unidentified role culminating with higher grain number and size.

  14. COSMOS-rice technology abrogates the biotoxic effects of municipal solid waste incinerator residues.

    PubMed

    Guarienti, Michela; Cardozo, Sdenka Moscoso; Borgese, Laura; Lira, Gloria Rodrigo; Depero, Laura E; Bontempi, Elza; Presta, Marco

    2016-07-01

    Fly ashes generated by municipal solid waste incinerator (MSWI) are classified as hazardous waste and usually landfilled. For the sustainable reuse of these materials is necessary to reduce the resulting impact on human health and environment. The COSMOS-rice technology has been recently proposed for the treatment of fly ashes mixed with rice husk ash, to obtain a low-cost composite material with significant performances. Here, aquatic biotoxicity assays, including daphnidae and zebrafish embryo-based tests, were used to assess the biosafety efficacy of this technology. Exposure to lixiviated MSWI fly ash caused dose-dependent biotoxic effects on daphnidae and zebrafish embryos with alterations of embryonic development, teratogenous defects and apoptotic events. On the contrary, no biotoxic effects were observed in daphnidae and zebrafish embryos exposed to lixiviated COSMOS-rice material. Accordingly, whole-mount in situ hybridization analysis of the expression of various tissue-specific genes in zebrafish embryos provided genetic evidence about the ability of COSMOS-rice stabilization process to minimize the biotoxic effects of MSWI fly ash. These results demonstrate at the biological level that the newly developed COSMOS-rice technology is an efficient and cost-effective method to process MSWI fly ash, producing a biologically safe and reusable material.

  15. Arsenic Concentrations in Rice and Associated Health Risks Along the Upper Mekong Delta, Cambodia

    NASA Astrophysics Data System (ADS)

    Barragan, L.; Seyfferth, A.; Fendorf, S.

    2011-12-01

    The consumption of arsenic contaminated food, such as rice, can be a significant portion of daily arsenic exposure, even for populations already exposed through drinking water. While arsenic contamination of rice grains has been documented in parts of Southern Asia, (e.g. Bangladesh), little research has been conducted on arsenic contamination of Cambodian-grown rice. We collected rice plant samples at various locations within the upper Mekong River Delta near Phnom Penh, Cambodia, and we analyzed total arsenic concentrations in plant digests of grains, husk, and straw. In addition, we used CaCl2-, DTPA-, and oxalate-extractable arsenic to define plant-available soil pools. We found variability of arsenic concentration in the plants, with grain arsenic ranging from 0.046 to 0.214 μg g-1; other researchers have shown that concentrations higher than 0.1 μg g-1 could be a concern for human health. Although more extensive sampling is needed to assess the risk of arsenic exposure from rice consumption on a country-wide basis, our work clearly illustrates the risk within regions of the Mekong Delta.

  16. Determination and study on dissipation and residue determination of cyhalofop-butyl and its metabolite using HPLC-MS/MS in a rice ecosystem.

    PubMed

    Wu, Junxue; Wang, Kai; Zhang, Yun; Zhang, Hongyan

    2014-10-01

    Cyhalofop-butyl is an aryloxyphenoxypropionate postemergence herbicide with good control of barnyard grass in rice paddies. In this study, method for the determination of cyhalofop-butyl and its metabolite was developed with high-performance liquid chromatography tandem mass spectrometry. Dissipation and residue levels of cyhalofop-butyl and its metabolite in rice ecosystems were also investigated. Recoveries and relative standard deviations of cyhalofop-butyl and cyhalofop acid in six matrices at three spiking levels ranged from 76.1 to 107.5% and 1.1 to 8.2%, respectively. The limit of quantitation (LOQ) of cyhalofop-butyl and cyhalofop acid was 0.01 mg/kg in paddy water, paddy soil, rice plant, rice straw, rice hulls, and husked rice. For field experiments, the results showed that cyhalofop-butyl degraded to cyhalofop acid quickly, and the half-lives of cyhalofop acid in paddy water, paddy soil, and rice plant were 1.01-1.53, 0.88-0.97, and 2.09-2.42 days, respectively. Ultimate residues of cyhalofop-butyl and its metabolite in the rice samples were not detectable or below 0.01 mg/kg at harvest.

  17. Orchestration of three transporters and distinct vascular structures in node for intervascular transfer of silicon in rice.

    PubMed

    Yamaji, Naoki; Sakurai, Gen; Mitani-Ueno, Namiki; Ma, Jian Feng

    2015-09-08

    Requirement of mineral elements in different plant tissues is not often consistent with their transpiration rate; therefore, plants have developed systems for preferential distribution of mineral elements to the developing tissues with low transpiration. Here we took silicon (Si) as an example and revealed an efficient system for preferential distribution of Si in the node of rice (Oryza sativa). Rice is able to accumulate more than 10% Si of the dry weight in the husk, which is required for protecting the grains from water loss and pathogen infection. However, it has been unknown for a long time how this hyperaccumulation is achieved. We found that three transporters (Lsi2, Lsi3, and Lsi6) located at the node are involved in the intervascular transfer, which is required for the preferential distribution of Si. Lsi2 was polarly localized to the bundle sheath cell layer around the enlarged vascular bundles, which is next to the xylem transfer cell layer where Lsi6 is localized. Lsi3 was located in the parenchyma tissues between enlarged vascular bundles and diffuse vascular bundles. Similar to Lsi6, knockout of Lsi2 and Lsi3 also resulted in decreased distribution of Si to the panicles but increased Si to the flag leaf. Furthermore, we constructed a mathematical model for Si distribution and revealed that in addition to cooperation of three transporters, an apoplastic barrier localized at the bundle sheath cells and development of the enlarged vascular bundles in node are also required for the hyperaccumulation of Si in rice husk.

  18. Silicon isotope fractionation between rice plants and nutrient solution and its significance to the study of the silicon cycle

    NASA Astrophysics Data System (ADS)

    Ding, T. P.; Tian, S. H.; Sun, L.; Wu, L. H.; Zhou, J. X.; Chen, Z. Y.

    2008-12-01

    The silicon isotope fractionation between rice plant and nutrient solution was studied experimentally. Rice plants were grown to maturity with the hydroponic culture in a naturally lit glasshouse. The nutrient solution was sampled for 14 times during the whole rice growth period. The rice plants were collected at various growth stages and different parts of the plants were sampled separately. The silica contents of the samples were determined by the gravimetric method and the silicon isotope compositions were measured using the SiF 4 method. In the growth process, the silicon content in the nutrient solution decreased gradually from 16 mM at starting stage to 0.1-0.2 mM at harvest and the amount of silica in single rice plant increased gradually from 0.00013 g at start to 4.329 g at harvest. Within rice plant the SiO 2 fraction in roots reduced continuously from 0.23 at the seedling stage, through 0.12 at the tiller stage, 0.05 at the jointing stage, 0.023 at the heading stage, to 0.009 at the maturity stage. Accordingly, the fraction of SiO 2 in aerial parts increased from 0.77, through 0.88, 0.95, 0.977, to 0.991 for the same stages. The silicon content in roots decreased from the jointing stage, through the heading stage, to the maturity stage, parallel to the decrease of silicon content in the nutrient solution. At the maturity stage, the silicon content increased from roots, through stem and leaves, to husks, but decreased drastically from husks to grains. These observations show that transpiration and evaporation may play an important role in silica transportation and precipitation within rice plants. It was observed that the δ30Si of the nutrient solution increased gradually from -0.1‰ at start to 1.5‰ at harvest, and the δ30Si of silicon absorbed by bulk rice plant increased gradually from -1.72‰ at start to -0.08‰ at harvest, reflecting the effect of the kinetic silicon isotope fractionation during silicon absorption by rice plants from nutrient

  19. Research in rice fields

    USGS Publications Warehouse

    ,

    2000-01-01

    Between 1987 and 1999, 2.4-3 million acres of rice were planted annually nationwide. Rice fields are a major component of the contemporary landscapes in the Gulf Coastal Plain, the Mississippi Alluvial Valley, and Central Valley of California. In 1998, approximately 600,000 acres of rice were planted in Louisiana. In the Louisiana plant commodities report for 1998, total value for rice was over $350 million; sugarcane was the only plant commodity that exceeded this value. Louisiana has over 2,000 rice farmers supporting over 12,000 jobs in the state. Rice fields in the United States receive high use by wildlife, especially shorebirds, wading birds, and waterfowl. Waterbirds use rice fields for food, shelter, and breeding habitat.

  20. Antioxidant potential of Juglans nigra, black walnut, husks extracted using supercritical carbon dioxide with an ethanol modifier.

    PubMed

    Wenzel, Jonathan; Storer Samaniego, Cheryl; Wang, Lihua; Burrows, Laron; Tucker, Evan; Dwarshuis, Nathan; Ammerman, Michelle; Zand, Ali

    2017-03-01

    The black walnut, Junglas nigra, is indigenous to eastern North America, and abscission of its fruit occurs around October. The fruit consists of a husk, a hard shell, and kernel. The husk is commonly discarded in processing, though it contains phenolic compounds that exhibit antioxidant and antimicrobial properties. For this study, black walnut husks were extracted using supercritical carbon dioxide with an ethanol modifier. The effects of temperature, ethanol concentration, and drying of walnut husks prior to extraction upon antioxidant potential were evaluated using a factorial design of experiments. The solvent density was held constant at 0.75 g/mL. The optimal extraction conditions were found to be 68°C and 20 wt-% ethanol in supercritical carbon dioxide. At these conditions, the antioxidant potential as measured by the ferric reducing ability of plasma (FRAP) assay was 0.027 mmol trolox equivalent/g (mmol TE/g) for dried walnut husk and 0.054 mmol TE/g for walnut husks that were not dried. Antioxidant potential was also evaluated using the total phenolic content (TPC) and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) assays and the FRAP assay was found to linearly correlate to the TPC assay.

  1. Phenol Biodegradation by Free and Immobilized Candida tropicalis RETL-Crl on Coconut Husk and Loofah Packed in Biofilter Column

    NASA Astrophysics Data System (ADS)

    Shazryenna, D.; Ruzanna, R.; Jessica, M. S.; Piakong, M. T.

    2015-04-01

    Phenols and its derivatives are environmental pollutant commonly found in many industrial effluents. It is toxic in nature and causes various health hazards. However, they are poorly removed in conventional biological processes due to their toxicity. Immobilization of microbial cells has received increasing interest in the field of waste treatment and creates opportunities in a wide range of sectors including environmental pollution control. Live cells of phenol-degrading yeast, Candida tropicalis RETL-Crl, were immobilized on coconut husk and loofah by adsorption. The immobolized particle was packed into biofilter column which used for continuous treatment of a phenol with initial phenol concentration of 3mM. Both loofah and coconut husk have similar phenol biodegradation rate of 0.0188 gL-1h-1 within 15 hours to achieve a phenol removal efficiency of 100%. However loofah have lower biomass concentration of 4.22 gL-1 compared to biomass concentration on coconut husk, 4.39 gL-1. Coconut husk contain higher biomass concentration which makes it better support material than loofah. Fibrous matrices such as loofah and coconut husk provide adequate supporting surfaces for cell adsorption, due to their high specific surface area. Therefore, coconut husk and loofah being an agricultural waste product have the potential to be used as low-cost adsorbent and support matrix for microbial culture immobilization for the removal of organic pollutant from wastewater.

  2. Grain Unloading of Arsenic Species in Rice1[W

    PubMed Central

    Carey, Anne-Marie; Scheckel, Kirk G.; Lombi, Enzo; Newville, Matt; Choi, Yongseong; Norton, Gareth J.; Charnock, John M.; Feldmann, Joerg; Price, Adam H.; Meharg, Andrew A.

    2010-01-01

    Rice (Oryza sativa) is the staple food for over half the world's population yet may represent a significant dietary source of inorganic arsenic (As), a nonthreshold, class 1 human carcinogen. Rice grain As is dominated by the inorganic species, and the organic species dimethylarsinic acid (DMA). To investigate how As species are unloaded into grain rice, panicles were excised during grain filling and hydroponically pulsed with arsenite, arsenate, glutathione-complexed As, or DMA. Total As concentrations in flag leaf, grain, and husk, were quantified by inductively coupled plasma mass spectroscopy and As speciation in the fresh grain was determined by x-ray absorption near-edge spectroscopy. The roles of phloem and xylem transport were investigated by applying a ± stem-girdling treatment to a second set of panicles, limiting phloem transport to the grain in panicles pulsed with arsenite or DMA. The results demonstrate that DMA is translocated to the rice grain with over an order magnitude greater efficiency than inorganic species and is more mobile than arsenite in both the phloem and the xylem. Phloem transport accounted for 90% of arsenite, and 55% of DMA, transport to the grain. Synchrotron x-ray fluorescence mapping and fluorescence microtomography revealed marked differences in the pattern of As unloading into the grain between DMA and arsenite-challenged grain. Arsenite was retained in the ovular vascular trace and DMA dispersed throughout the external grain parts and into the endosperm. This study also demonstrates that DMA speciation is altered in planta, potentially through complexation with thiols. PMID:19880610

  3. Cooked rice texture and rice flour pasting properties; impacted by rice temperature during milling.

    PubMed

    Saleh, Mohammed; Meullenet, Jean-Francois

    2015-03-01

    Rice milling plays a key factor in determining rice quality and value. Therefore accurate quality assessments are critical to the rice industry. This study was undertaken to assess the effect of exposing rice to elevated temperatures during milling, on cooked rice texture and rice flour pasting properties. Two long (Cybonnett and Francis) and one medium (Jupiter) rice (oryzae sativa L.) cultivars were milled using McGill laboratory mill for 30 and 40 s after warmed up the mill before milling. Four different milling temperatures per milling duration were achieved. Cooked rice texture properties were assessed using a uniaxial compression test and rice flour pasting properties measured using a TA-2000 rheometer. Results of this study showed that exposure of rice to high temperatures during milling significantly decreased cooked rice firmness. An increase in milled rice temperature after milling from 10.0 to 13.3 °C resulted in a 5.4 and 8.1 N decrease in cooked rice firmness. Although not always significant, the increase in milled rice temperature during milling resulted in an increase in cooked rice stickiness. The increase in milling temperature also showed significant increase in rice flour pasting properties. Changes in rice functional characteristics were attributed to the changes occurring to rice chemical constituents due to temperature exposure as indicated by the increase in rice protein hydrophobicity. Proteins are known to affect rice starch water holding capacity and other starch gelatinization properties.

  4. The availabilities of arsenic and cadmium in rice paddy fields from a mining area: The role of soil extractable and plant silicon.

    PubMed

    Yu, Huan-Yun; Ding, Xiaodong; Li, Fangbai; Wang, Xiangqin; Zhang, Shirong; Yi, Jicai; Liu, Chuanping; Xu, Xianghua; Wang, Qi

    2016-08-01

    Adequate silicon (Si) can greatly boost rice yield and improve grain quality through alleviating stresses associated with heavy metals and metalloids such as arsenic (As) and cadmium (Cd). The soil plant-available Si is relatively low in South China due to severe desilicification and allitization of the soils in this region. Conversely, pollution of heavy metals and metalloids in the soils of this region occurs widely, especially As and Cd pollution in paddy soil. Therefore, evaluating the plant availability of Si in paddy soil of South China and examining its correlation with the availability of heavy metals and metalloids are of great significance. Accordingly, in our study, 107 pairs of soil and rice plant samples were collected from paddy fields contaminated by As and Cd in South China. Significantly positive correlations between Si in rice plants and Si fractions in soils extracted with citric acid, NaOAc-HOAc buffer, and oxalate-ammonium oxalate buffer suggest that these extractants are more suitable for use in extracting plant-available Si in the soils of our present study. Significantly negative correlations between different Si fractions and As or Cd in rice plant tissues and negative exponential correlations between the molar ratios of Si to As/Cd in rice roots, straws, husks or grains and As/Cd in rice grains indicate that Si can significantly alleviate the accumulation of As/Cd from soils to the rice plants. Finally, a contribution assessment of soil properties to As/Cd accumulation in rice grains based on random forest showed that in addition to Si concentrations in soil or rice plants, other factors such as Fe fractions and total phosphorus also contributed largely to As/Cd accumulation in rice grains. Overall, Si exhibited its unique role in mitigating As or Cd stress in rice, and our study results provide strong field evidence for this role.

  5. Simulation of Heat Transfer in Husk Furnace with Cone Geometry Based on Conical Coordinate System

    NASA Astrophysics Data System (ADS)

    Noor, Iman; Ahmad, Faozan; Irzaman; alatas, Husin

    2017-07-01

    Simulation of Heat Transfer in Husk Furnace with Cone Geometry Based on Conical Coordinates has been performed. This simulation aimed to study the heat distribution of temperature based on conduction and convection mechanism on conical coordinate system. Fluid dynamics inside the cone of husk furnace was obtained by solving the Navier - Stokes equations with laminar flow approach. The initial temperature in all parts of the cone is room temperature, except at the bottom of the cone is 700 °C. Through numerical calculation of heat conduction and convection equation by FDM method, we got that the velocity of fluid flow at the center cone is 13.69 m/s for 45 s, 11.90 m/s for 60 s, and 7.25 m/s for 120 s, with unfixed temperature condition in the cone.

  6. Rapid analysis of avenacosides in grain and husks of oats by UPLC-TQ-MS.

    PubMed

    Pecio, Łukasz; Wawrzyniak-Szołkowska, Aleksandra; Oleszek, Wiesław; Stochmal, Anna

    2013-12-01

    Avenacosides A (AA) and B (AB) as well as 26-desglucoavenacoside A (26dAA) were quantified in oats using rapid and sensitive method utilising UPLC-TQ-MS. In the grain, AA and AB were revealed as the primary saponins, whereas in the husks, dAA was predominant. Inconsistent with the published data, observed concentrations of AA and AB in the grain were very similar. Presumably, this is due to higher sensitivity and better selectivity of the mass spectrometry-based quantification method, thus allowing for more precise measurements. Elevated level of an active fungicidal form of saponin, dAA in the husks possibly indicates they are more prone to fungal attacks.

  7. Redefining the bureaucratic encounter between service providers and service users: evidence from the Norwegian HUSK projects.

    PubMed

    Carnochan, Sarah; Austin, Michael J

    2015-01-01

    The HUSK projects, involving collaboration between service users, providers, educators, and researchers, coincided with the reorganization of national government services (NAV). The NAV reorganization brought together employment services, social insurance, and municipal social service benefits, and called for a service model where users would be empowered to influence the provision of services. In this analysis of the HUSK cases the authors focus on the relationship between the service user and the service provider, identifying themes in two broad domains: concepts of the individual that included the service user and the service provider and concepts of the relationship that included power, role, activity, interaction, and communication. Within each theme, the analysis highlights the transition from a traditional or historical state to a new or desired state and draws upon some of the classic literature that frames the encounters between service users and providers.

  8. Coffee husk composting: An investigation of the process using molecular and non-molecular tools

    PubMed Central

    Shemekite, Fekadu; Gómez-Brandón, María; Franke-Whittle, Ingrid H.; Praehauser, Barbara; Insam, Heribert; Assefa, Fassil

    2014-01-01

    Various parameters were measured during a 90-day composting process of coffee husk with cow dung (Pile 1), with fruit/vegetable wastes (Pile 2) and coffee husk alone (Pile 3). Samples were collected on days 0, 32 and 90 for chemical and microbiological analyses. C/N ratios of Piles 1 and 2 decreased significantly over the 90 days. The highest bacterial counts at the start of the process and highest actinobacterial counts at the end of the process (Piles 1 and 2) indicated microbial succession with concomitant production of compost relevant enzymes. Denaturing gradient gel electrophoresis of rDNA and COMPOCHIP microarray analysis indicated distinctive community shifts during the composting process, with day 0 samples clustering separately from the 32 and 90-day samples. This study, using a multi-parameter approach, has revealed differences in quality and species diversity of the three composts. PMID:24369846

  9. A new naphthalenone isolated from the green walnut husks of Juglans mandshurica Maxim.

    PubMed

    Chen, Guang; Pi, Xin-Mei; Yu, Chang-Yuan

    2015-01-01

    Phytochemical study of green walnut husks of Juglans mandshurica Maxim. led to the isolation of a new naphthalenone, (4R)-3,4-dihydro-4-butoxy-5-hydroxy-naphthalen-1(2H)-one (1), together with 16 known compounds. Compounds 4-6, 13, 14 and 17 were isolated from the genus Juglans for the first time, and their chemotaxonomic significance was also evaluated.

  10. Coffee husk mulch on soil erosion and runoff: experiences under rainfall simulation experiment

    NASA Astrophysics Data System (ADS)

    Moreno-Ramón, H.; Quizembe, S. J.; Ibáñez-Asensio, S.

    2014-08-01

    The high erosion rates found in the agriculture land make valuable the use of mulches to control the soil and water losses. Coffee husk (Coffea canephora var. robusta) can be one of those mulches. This paper evaluates how to apply the mulch in order to obtain the best effectiveness. An experimental factorial design 4 × 3 × 2 with two replicates was designed in a greenhouse with a total number of 48 cases. All the samples were deposited in trays of 0.51 m2 and applied a simulated rain of 122 mm h-1 during 21 min. The factors examined were the following: four soil classes; three treatments - buried (B), surface (S) and non-residue (C) - and the presence (WC) or absence (WOC) of the soil surface crusting. The coffee husk residue (S and B treatments) reduced runoff by 10.2 and 46% respectively, soil losses by 78.3 and 88.7% and sediment concentration by 77 and 84.4%. The infiltration rate increased on average by 104 and 167%, and time to runoff by 1.58 and 2.07 min respectively. Coffee husk is an efficient mulch to reduce the soil and water losses, although it could not completely cushion the influence of crust.

  11. Enhancing nutrient recovery and compost maturity of coconut husk by vermicomposting technology.

    PubMed

    Swarnam, T P; Velmurugan, A; Pandey, Sanjay Kumar; Dam Roy, S

    2016-05-01

    Vermicompost was prepared by five different treatments from relatively resistant coconut husk mixed with either pig slurry or poultry manure. The recovery of vermicompost varied from 35% to 43% and it resulted in significant increase in pH, microbial biomass carbon, macro and micro nutrients concentration. Among the treatments highest relative N (1.6) and K (1.3) recovery were observed for 20% feedstock substitution by pig slurry while poultry manure substitution recorded highest P recovery (2.4). Compost maturity parameters significantly differed and well correlated. The characteristics of different treatments established the maturity indices as C/N 15-20; Cw<1.8; Cw/Norg<0.55; Lignin<10-12; CHA/CFA>1.5 and HI>15.0. The manurial value of the coconut husk compost was improved by feedstock substitution with pig slurry (80:20). The results revealed the technical feasibility of converting coconut husk into valuable compost by feedstock substitution with pig slurry.

  12. Effect of self-purging pyrolysis on yield of biochar from maize cobs, husks and leaves.

    PubMed

    Intani, Kiatkamjon; Latif, Sajid; Kabir, A K M Rafayatul; Müller, Joachim

    2016-10-01

    In this study, biochar was produced from maize residues (cobs, husks, leaves) in a lab-scale pyrolysis reactor without using a purging gas. The physicochemical properties of biomass and biochar were analysed. Box-Behnken design was used to optimise operational conditions for biochar yields. Multivariate correlations of biochar yields were established using reduced quadratic models with R(2)=0.9949, 0.9801 and 0.9876 for cobs, husks and leaves, respectively. Biochar yields were negatively correlated with the temperature, which was significantly influenced by the exothermic reactions during the pyrolysis of maize residues. The heating rate was found to have the least effect on biochar yields. Under optimal conditions, the maximum biochar yields from cobs, husks and leaves were 33.42, 30.69 and 37.91%, respectively. The highest biochar yield from maize leaves was obtained at a temperature of 300°C, a heating rate of 15°C/min and a holding time of 30min. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Production, statistical optimization and application of endoglucanase from Rhizopus stolonifer utilizing coffee husk.

    PubMed

    Navya, P N; Pushpa, S Murthy

    2013-08-01

    Coffee cherry husk (CH) is one of the major by-products obtained from coffee processing industry and accounts to 43 ± 5.9% of cellulose. Screening of fungal organism for cellulase production was carried out and the potential organism was identified as Rhizopus stolonifer by internal transcribed spacer's (ITS)-5.8S rDNA analysis. A systematic study with response surface methodology (RSM) based on CCRD was used to study the interactions among the variables such as pH (3-7), moisture (40-80%) and progression duration (72-168 h) of the fermentation process to maximize the enzyme production. Under the optimized cultivation condition, R. stolonifer synthesized 22,109 U/gds. Model validations at optimum operating conditions showed excellent agreement between the experimental results and the predicted responses with a confidence level of 95%. Endoglucanase thus produced was utilized for ethanol production by simultaneous saccharification and fermentation and maximum of 65.5 g/L of ethanol was obtained. This fungal cellulase has also reported to be efficient detergent additives and promising for commercial use. The present study demonstrates coffee husk as a significant bioprocess substrate. Statistical optimization with major parameters for cellulase production can be highly applicable for industrial scale. Furthermore, value addition to coffee husk with sustainable waste management leading to environment conservation can be achieved.

  14. Speciation and distribution of arsenic and localization of nutrients in rice grains.

    PubMed

    Lombi, E; Scheckel, K G; Pallon, J; Carey, A M; Zhu, Y G; Meharg, A A

    2009-01-01

    Arsenic (As) contamination of rice grains and the generally low concentration of micronutrients in rice have been recognized as a major concern for human health. Here, we investigated the speciation and localization of As and the distribution of (micro)nutrients in rice grains because these are key factors controlling bioavailability of nutrients and contaminants. Bulk total and speciation analyses using high-pressure liquid chromatography (HPLC)-inductively coupled plasma mass spectrometry (ICP-MS) and X-ray absorption near-edge spectroscopy (XANES) was complemented by spatially resolved microspectroscopic techniques (micro-XANES, micro-X-ray fluorescence (micro-XRF) and particle induced X-ray emission (PIXE)) to investigate both speciation and distribution of As and localization of nutrients in situ. The distribution of As and micronutrients varied between the various parts of the grains (husk, bran and endosperm) and was characterized by element-specific distribution patterns. The speciation of As in bran and endosperm was dominated by As(III)-thiol complexes. The results indicate that the translocation from the maternal to filial tissues may be a bottleneck for As accumulation in the grain. Strong similarities between the distribution of iron (Fe), manganese (Mn) and phosphorus (P) and between zinc (Zn) and sulphur (S) may be indicative of complexation mechanisms in rice grains.

  15. Speciation and distribution of arsenic and localization of nutrients in rice grains

    SciTech Connect

    Lombi, E.; Scheckel, K.G.; Pallon, J.; Carey, A.M.; Zhu, Y.G.; Meharg, A.A.

    2012-09-05

    Arsenic (As) contamination of rice grains and the generally low concentration of micronutrients in rice have been recognized as a major concern for human health. Here, we investigated the speciation and localization of As and the distribution of (micro)nutrients in rice grains because these are key factors controlling bioavailability of nutrients and contaminants. Bulk total and speciation analyses using high-pressure liquid chromatography (HPLC)-inductively coupled plasma mass spectrometry (ICP-MS) and X-ray absorption near-edge spectroscopy (XANES) was complemented by spatially resolved microspectroscopic techniques ({mu}-XANES, {mu}-X-ray fluorescence ({mu}-XRF) and particle induced X-ray emission (PIXE)) to investigate both speciation and distribution of As and localization of nutrients in situ. The distribution of As and micronutrients varied between the various parts of the grains (husk, bran and endosperm) and was characterized by element-specific distribution patterns. The speciation of As in bran and endosperm was dominated by As(III)-thiol complexes. The results indicate that the translocation from the maternal to filial tissues may be a bottleneck for As accumulation in the grain. Strong similarities between the distribution of iron (Fe), manganese (Mn) and phosphorus (P) and between zinc (Zn) and sulphur (S) may be indicative of complexation mechanisms in rice grains.

  16. Reducing phosphorus accumulation in rice grains with an impaired transporter in the node.

    PubMed

    Yamaji, Naoki; Takemoto, Yuma; Miyaji, Takaaki; Mitani-Ueno, Namiki; Yoshida, Kaoru T; Ma, Jian Feng

    2017-01-05

    Phosphorus is an important nutrient for crop productivity. More than 60% of the total phosphorus in cereal crops is finally allocated into the grains and is therefore removed at harvest. This removal accounts for 85% of the phosphorus fertilizers applied to the field each year. However, because humans and non-ruminants such as poultry, swine and fish cannot digest phytate, the major form of phosphorus in the grains, the excreted phosphorus causes eutrophication of waterways. A reduction in phosphorus accumulation in the grain would contribute to sustainable and environmentally friendly agriculture. Here we describe a rice transporter, SULTR-like phosphorus distribution transporter (SPDT), that controls the allocation of phosphorus to the grain. SPDT is expressed in the xylem region of both enlarged- and diffuse-vascular bundles of the nodes, and encodes a plasma-membrane-localized transporter for phosphorus. Knockout of this gene in rice (Oryza sativa) altered the distribution of phosphorus, with decreased phosphorus in the grains but increased levels in the leaves. Total phosphorus and phytate in the brown de-husked rice were 20-30% lower in the knockout lines, whereas yield, seed germination and seedling vigour were not affected. These results indicate that SPDT functions in the rice node as a switch to allocate phosphorus preferentially to the grains. This finding provides a potential strategy to reduce the removal of phosphorus from the field and lower the risk of eutrophication of waterways.

  17. Fusarium Species from Nepalese Rice and Production of Mycotoxins and Gibberellic Acid by Selected Species

    PubMed Central

    Desjardins, A. E.; Manandhar, H. K.; Plattner, R. D.; Manandhar, G. G.; Poling, S. M.; Maragos, C. M.

    2000-01-01

    Infection of cereal grains with Fusarium species can cause contamination with mycotoxins that affect human and animal health. To determine the potential for mycotoxin contamination, we isolated Fusarium species from samples of rice seeds that were collected in 1997 on farms in the foothills of the Nepal Himalaya. The predominant Fusarium species in surface-disinfested seeds with husks were species of the Gibberella fujikuroi complex, including G. fujikuroi mating population A (anamorph, Fusarium verticillioides), G. fujikuroi mating population C (anamorph, Fusarium fujikuroi), and G. fujikuroi mating population D (anamorph, Fusarium proliferatum). The widespread occurrence of mating population D suggests that its role in the complex symptoms of bakanae disease of rice may be significant. Other common species were Gibberella zeae (anamorph, Fusarium graminearum) and Fusarium semitectum, with Fusarium acuminatum, Fusarium anguioides, Fusarium avenaceum, Fusarium chlamydosporum, Fusarium equiseti, and Fusarium oxysporum occasionally present. Strains of mating population C produced beauvericin, moniliformin, and gibberellic acid, but little or no fumonisin, whereas strains of mating population D produced beauvericin, fumonisin, and, usually, moniliformin, but no gibberellic acid. Some strains of G. zeae produced the 8-ketotrichothecene nivalenol, whereas others produced deoxynivalenol. Despite the occurrence of fumonisin-producing strains of mating population D, and of 8-ketotrichothecene-producing strains of G. zeae, Nepalese rice showed no detectable contamination with these mycotoxins. Effective traditional practices for grain drying and storage may prevent contamination of Nepalese rice with Fusarium mycotoxins. PMID:10698766

  18. Determinants for grading Malaysian rice

    NASA Astrophysics Data System (ADS)

    ChePa, Noraziah; Yusoff, Nooraini; Ahmad, Norhayati

    2016-08-01

    Due to un-uniformity of rice grading practices in Malaysia, zones which actively producing rice in Malaysia are using their own way of grading rice. Rice grading is important in determining rice quality and its subsequent price in the market. It is an important process applied in the rice production industry with the purpose of ensuring that the rice produced for the market meets the quality requirements of consumer. Two important aspects that need to be considered in determining rice grades are grading technique and determinants to be used for grading (usually referred as rice attributes). This article proposes the list of determinants to be used in grading Malaysian rice. Determinants were explored through combination of extensive literature review and series of interview with the domain experts and practitioners. The proposed determinants are believed to be beneficial to BERNAS in improving the current Malaysian rice grading process.

  19. Relating raw rice color and composition to cooked rice color.

    USDA-ARS?s Scientific Manuscript database

    Traditionally, the color of milled rice is economically important. The whiter the rice the more it is preferred by consumers and the more value it has in the market place. Little attention has been given to relating raw rice color to cooked milled rice color and, specifically, to determining the i...

  20. Elemental bioimaging of tissue level trace metal distributions in rice seeds (Oryza sativa L.) from a mining area in China.

    PubMed

    Basnet, Priyanka; Amarasiriwardena, Dulasiri; Wu, Fengchang; Fu, Zhiyou; Zhang, Tao

    2014-12-01

    Rice is a staple food and major source of nutrients, but it also bioaccumulates toxic elements. In this study, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used to determine tissue-level trace metal spatial distribution in rice (Oryza sativa) seeds from the active Xikuangshan Sb mine area in China. Whole grain quantified elemental bioimages showed the highest concentration of Zn (1755 mg/kg) in the embryo andmicro zones of elevated Sb, As, Pb, Cd as high as 280, 57, 31 and 830 mg/kg, respectively on the husk/bran/endosperm tissues. Bioimages suggest that both Sb and Cd may be competing with Zn for binding sites. Both Sb(III) and Sb(V) species were detected in seeds from upstream and downstream fields indicating the presence of toxic Sb(III). Brown rice is a good source of Zn, but white rice is a safer option if rice is grown in a polluted area. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. OsFRDL1 expressed in nodes is required for distribution of iron to grains in rice

    PubMed Central

    Yokosho, Kengo; Yamaji, Naoki; Ma, Jian Feng

    2016-01-01

    Iron (Fe) is essential for plant growth and development, but the molecular mechanisms underlying its distribution to different organs are poorly understood. We found that OsFRDL1 (FERRIC REDUCTASE DEFECTIVE LIKE 1), a plasma membrane-localized transporter for citrate, was highly expressed in the upper nodes of rice at the reproductive growth stage. OsFRDL1 was expressed in most cells of enlarged vascular bundles, diffuse vascular bundles, and the interjacent parenchyma cell bridges of uppermost node I, as well as vascular tissues of the leaf blade, leaf sheath, peduncle, rachis, husk, and stamen. Knockout of OsFRDL1 decreased pollen viability and grain fertility when grown in a paddy field. Iron was deposited in the parenchyma cell bridges, a few of the cell layers of the parenchyma tissues outside of the bundle sheath of enlarged vascular bundles in node I in both the wild-type rice and osfrdl1 mutant, but the mutant accumulated more Fe than the wild-type rice in this area. A stem-fed experiment with stable isotope 57Fe showed that the distribution of Fe in the anther and panicle decreased in the knockout line, but that in the flag leaf it increased compared with the wild-type rice. Taken together, our results show that OsFRDL1 expressed in the upper nodes is required for the distribution of Fe in the panicles through solubilizing Fe deposited in the apoplastic part of nodes in rice. PMID:27555544

  2. Rice (Oryza) hemoglobins

    USDA-ARS?s Scientific Manuscript database

    Hemoglobins (Hbs) corresponding to non-symbiotic (nsHb) and truncated (tHb) Hbs have been identified in rice (Oryza). This review discusses the major findings from the current studies on rice Hbs. At the molecular level, a family of the nshb genes, consisting of hb1, hb2, hb3, hb4 and hb5, and a sin...

  3. Making rice even healthier!

    USDA-ARS?s Scientific Manuscript database

    Rice is a naturally healthy food, but what if it could be made even healthier? Would Americans eat more rice if it could be advertised to be a 'New and Improved' source of calcium to promote bone growth, or iron to prevent anemia? Grocery stores are full of foods that are vitamin enhanced to attract...

  4. Effect of biochars and microorganisms on cadmium accumulation in rice grains grown in Cd-contaminated soil.

    PubMed

    Suksabye, Parinda; Pimthong, Apinya; Dhurakit, Prapai; Mekvichitsaeng, Phenjun; Thiravetyan, Paitip

    2016-01-01

    Cadmium (Cd) contaminated in rice grains is a serious problem because most Asians consume rice on a daily basis. Rice grown in Cd-contaminated soil normally did not have high concentration of Cd. However, soil samples used in this study had high concentrations of Cd. The purpose of this study was to clearly see the effects of biochar and microorganism addition in rice growing in Cd-contaminated soil. The initial Cd concentration in Cd-contaminated soil used in this study was about 650 mg kg(-1). Cadmium concentration in rice plants grown in Cd-contaminated soil with the addition of 1% (w/w) different biochars such as sawdust fly ash (SDFA), bagasse fly ash (BGFA), and rice husk ash (RHA) was investigated. The results showed that SDFA was the best biochar in terms of reducing cadmium accumulation in rice grains when compared to BGFA and RHA under the same conditions. In addition, rice plants grown in Cd-contaminated soil with the addition of various nonpathogenic microorganisms, such as Pseudomonas aeruginosa, Bacillus subtilis, and Beauveria bassiana were also studied. The results showed that the addition of 2% (v/v) microorganisms can reduce Cd accumulation in grains. It was found that grains obtained from Cd-contaminated soil with the addition of P. aeruginosa had the lowest cadmium concentration compared to the ones from soil amended with other strains. This was due to the fact that P. aeruginosa adsorbed more Cd itself into its cells than other strains. The rice plants grown in Cd-contaminated soil with the addition of biochars and microorganisms were also compared. The results showed that adding 2% (v/v) microorganisms seemed to reduce Cd accumulation in rice grains better than adding 1% (w/w) biochars. In addition, the amounts of calcium and magnesium in rice grains and the dry weight of plant in Cd-contaminated soil amended with P. aeruginosa were the highest in comparison to other microorganisms, biochars, and the soil without any amendments (Cd

  5. Effects of husk and harvest time on carotenoid content and acceptability of roasted fresh cobs of orange maize hybrids

    PubMed Central

    Alamu, Oladeji E; Menkir, Abebe; Maziya-Dixon, Bussie; Olaofe, Olorunfemi

    2014-01-01

    Vitamin A deficiency (VAD) is a major public health problem in many developing countries. Orange maize is preferred as green maize and consumed roasted on the cob, especially in Nigeria. This research work was to evaluate the effects of harvest time and husk on the carotenoid contents and sensory properties of roasted orange maize hybrids. The results showed that husk (roasting forms) and harvesting time had significant effects (P ≤ 0.001) on the carotenoids and the sensory properties. There was general increase in β-carotene and provitamin A (PVA) values as the harvesting time increases. The β-carotene and PVA values for roasted orange maize hybrids with husk were higher than those for roasted without husk. Hybrid 5 had the highest β-carotene concentration and PVA value at 27 days after pollination (DAP) and 34DAP when unprocessed and roasted without husk. This information can help researchers in choosing proper roasting methods to increase the retention of high levels of β-carotene and PVA in orange maize that can be delivered to consumers through nutrition education. PMID:25493200

  6. The hybrid photocatalyst of TiO2-SiO2 thin film prepared from rice husk silica

    NASA Astrophysics Data System (ADS)

    Klankaw, P.; Chawengkijwanich, C.; Grisdanurak, N.; Chiarakorn, Siriluk

    2012-03-01

    The TiO2-SiO2 thin film was prepared by self-assembly method by mixing SiO2 precursor with titanium precursor solution and aged to obtain a co-precipitation of silica and titanium crystals. Dip coating method was applied for thin film preparation on glass slide. The X-ray diffraction (XRD) of the self-assembly thin film had no characteristic property of SiO2 and even anatase TiO2 but indicated new crystal structure which was determined from the Fourier Transform Infrared Spectrophotometer (FTIR) as a hybridized Ti-O-Si bonding. The surface area and surface volume of the self-assembly sample were increased when SiO2 was incorporated into the film. The self-assembly TiO2-SiO2 thin film exhibited the enhanced photocatalytic decolorization of methylene blue (MB) dye. The advantages of SiO2 are; (1) to increase the adsorbability of the film and (2) to provide the hydroxyl radical to promote the photocatalytic reaction. The self-assembly thin film with the optimum molar ratio (SiO2:TiO2) as 20:80 gave the best performance for photocatalytic decolorization of MB dye with the overall efficiency of 81%.

  7. Non-specific phospholipase C1 affects silicon distribution and mechanical strength in stem nodes of rice.

    PubMed

    Cao, Huasheng; Zhuo, Lin; Su, Yuan; Sun, Linxiao; Wang, Xuemin

    2016-05-01

    Silicon, the second abundant element in the crust, is beneficial for plant growth, mechanical strength, and stress responses. Here we show that manipulation of the non-specific phospholipase C1, NPC1, alters silicon content in nodes and husks of rice (Oryza sativa). Silicon content in NPC1-overexpressing (OE) plants was decreased in nodes but increased in husks compared to wild-type, whereas RNAi suppression of NPC1 resulted in the opposite changes to those of NPC1-OE plants. NPC1 from rice hydrolyzed phospholipids and galactolipids to generate diacylglycerol that can be phosphorylated to phosphatidic acid. Phosphatidic acid interacts with Lsi6, a silicon transporter that is expressed at the highest level in nodes. In addition, the node cells of NPC1-OE plants have lower contents of cellulose and hemicellulose, and thinner sclerenchyma and vascular bundle fibre cells than wild-type plants; whereas NPC1-RNAi plants displayed the opposite changes. These data indicate that NPC1 modulates silicon distribution and secondary cell wall deposition in nodes and grains, affecting mechanical strength and seed shattering. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

  8. Fundamental and molecular composition characteristics of biochars produced from sugarcane and rice crop residues and by-products.

    PubMed

    Jeong, Chang Yoon; Dodla, Syam K; Wang, Jim J

    2016-01-01

    Biochar conversion of sugarcane and rice harvest residues provides an alternative for managing these crop residues that are traditionally burned in open field. Sugarcane leaves, bagasse, rice straw and husk were converted to biochar at four pyrolysis temperatures (PTs) of 450 °C, 550 °C, 650 °C, and 750 °C and evaluated for various elemental, molecular and surface properties. The carbon content of biochars was highest for those produced at 650-750 °C. Biochars produced at 550 °C showed the characteristics of biochar that are commonly interpreted as being stable in soil, with low H/C and O/C ratios and pyrolysis fingerprints dominated by aromatic and polyaromatic hydrocarbons. At 550 °C, all biochars also exhibited maximum CEC values with sugarcane leaves biochar (SLB) > sugarcane bagasse biochar (SBB) > rice straw biochar (RSB) > rice husk biochar (RHB). The pore size distribution of biochars was dominated by pores of 20 nm and high PT increased both smaller and larger than 50 nm pores. Water holding capacity of biochars increased with PT but the magnitude of the increase was limited by feedstock types, likely related to the hydrophobicity of biochars as evident by molecular composition, besides pore volume properties of biochars. Py-GC/MS analysis revealed a clear destruction of lignin with decarboxylation and demethoxylation at 450 °C and dehydroxylation at above 550 °C. Overall, biochar molecular compositions became similar as PT increased, and the biochars produced at 550 °C demonstrated characteristics that have potential benefit as soil amendment for improving both C sequestration and nutrient dynamics.

  9. Effect of microwave drying and oven drying on the water activity, color, phenolic compounds content and antioxidant activity of coconut husk (Cocos nucifera L.).

    PubMed

    Valadez-Carmona, Lourdes; Cortez-García, Rosa María; Plazola-Jacinto, Carla Patricia; Necoechea-Mondragón, Hugo; Ortiz-Moreno, Alicia

    2016-09-01

    The coconut (Cocos nucifera L.) husk is basically composed by fiber and pith material and remained under-utilized. This is an important source of phenolic compounds that could be used as functional ingredients. The aim of this study was to determine the effect of: oven-drying (OD) and microwave drying (MD), on the water activity, color, phenolic compound content and antioxidant activity of coconut husk. The OD was performed at 60 °C for 12 h and MD was performed at 900 W for 10 min. The total phenolic content (TPC) in fresh coconut husk was 64.2 mg GAE/g dry wt and significant higher than observed after OD and MD of 35.8 and 45.5 mg GAE/g dry wt, respectively. Ten phenols were identified in fresh and dehydrated coconut husks. The husk MD showed an increase in the content of gallic, 4-hydroxybenzoic, ferulic and syringic acids and epicatechin compared with the fresh; while coconut husk OD and MD, showed a decrease in the content of vanillic acid, vanillin, catequin and kaempferol. The antioxidant activity decreased after both OD and MD. However, MD resulted in a better antioxidant activity in husk than OD. MD of husk resulted into better retention of preserved color, TPC and TFC than OD.

  10. Comparison of liquid and vapor hydrothermal carbonization of corn husk for the use as a solid fuel.

    PubMed

    Minaret, Jamie; Dutta, Animesh

    2016-01-01

    The effect of the phase during the hydrothermal carbonization (HTC) of corn husks was studied to determine whether liquid water or water vapor was the more suitable reaction medium, as well as if the HTC process could produce a solid fuel (hydrochar) from green corn husks that was comparable to coal. Using liquid water for the HTC process produced a hydrochar with an increased heating value (27.66MJkg(-1)) compared to using water vapor (25.46MJkg(-1)). HTC using liquid water removed 90% of the potassium contained in raw corn husk, whereas the water vapor HTC treatment removed 58%. The liquid water treated hydrochar contained a 29% decrease in ash content compared to the water vapor hydrochar. Using a TGA-FTIR analysis the liquid treated hydrochar demonstrated a more coal-like combustion in terms of mass loss and heat production, compared to the vapor treated hydrochar. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Coffee husk: an inexpensive substrate for production of citric acid by Aspergillus niger in a solid-state fermentation system.

    PubMed

    Shankaranand, V S; Lonsane, B K

    1994-03-01

    Aspergillus niger CFTRI 30 produced 1.3 g citric acid/10 g dry coffee husk in 72 h solid-state fermentation when the substrate was moistened with 0.075 M NaOH solution. Production was increased by 17% by adding a mixture of iron, copper and zinc to the medium but enrichment of the moist solid medium with (NH4)2SO4, sucrose or any of four enzymes did not improve production. The production of about 1.5 g citric acid/10 g dry coffee husk at a conversion of 82% (based on sugar consumed) under standardized conditions demonstrates the commercial potential of using the husk in this way.

  12. Impact of postharvest drying conditions on in vitro starch digestibility and estimated glycemic index of cooked non-waxy long-grain rice (Oryza sativa L.).

    PubMed

    Donlao, Natthawuddhi; Ogawa, Yukiharu

    2017-02-01

    Wet paddy needs to be dried to reduce its moisture content after harvesting. In this study, effects of postharvest drying condition on in vitro starch digestibility and estimated glycemic index of cooked rice (Oryza sativa L.) were investigated. Varying drying conditions, i.e. hot-air drying at 40, 65, 90 and 115 °C, and sun drying were applied to raw paddy. After husking and polishing, polished grains were cooked using an electric rice cooker. Cooked samples were analyzed for their moisture content and amount of resistant and total starch. Five samples in both intact grain and slurry were digested under simulated in vitro gastrointestinal digestion process. The in vitro starch digestion rate was measured and the hydrolysis index (HI) and estimated glycemic index (eGI) were calculated. Cooked rice obtained from hot-air drying showed relatively lower HI and eGI than that obtained from sun-drying. Among samples from hot-air drying treatment, eGI of cooked rice decreased with increasing drying temperature, except for the drying temperature of 115 °C. As a result, cooked rice from the hot-air drying at 90 °C showed lowest eGI. The results indicated that cooked rice digestibility was affected by postharvest drying conditions. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  13. Blueberry husks and probiotics attenuate colorectal inflammation and oncogenesis, and liver injuries in rats exposed to cycling DSS-treatment.

    PubMed

    Håkansson, Asa; Bränning, Camilla; Molin, Göran; Adawi, Diya; Hagslätt, Marie-Louise; Jeppsson, Bengt; Nyman, Margareta; Ahrné, Siv

    2012-01-01

    Long-term colonic inflammation promotes carcinogenesis and histological abnormalities of the liver, and colorectal tumours frequently arise in a background of dysplasia, a precursor of adenomas. Altered colonic microbiota with an increased proportion of bacteria with pro-inflammatory characteristics, have been implicated in neoplastic progression. The composition of the microbiota can be modified by dietary components such as probiotics, polyphenols and dietary fibres. In the present study, the influence of probiotics in combination with blueberry husks on colorectal carcinogenesis and subsequent liver damage was evaluated.Colorectal tumours were induced in rats by cyclic treatment with dextran sulphate sodium (DSS). Blueberry husks and a mixture of three probiotic strains (Bifidobacterium infantis DSM 15159, Lactobacillus gasseri, DSM 16737 and Lactobacillus plantarum DSM 15313) supplemented a basic diet fortified with oats. The condition of the rats was monitored using a disease activity index (DAI). A qualitative and quantitative histological judgement was performed on segments of distal colon and rectum and the caudate lobe of the liver. The formation of short-chain fatty acids, bacterial translocation, the inflammatory reaction and viable count of lactobacilli and Enterobaceriaceae were addressed.Blueberry husks with or without probiotics significantly decreased DAI, and significantly reduced the number of colonic ulcers and dysplastic lesions. With a decreased proportion of blueberry husk in the diet, the probiotic supplement was needed to achieve a significant decrease in numbers of dysplastic lesions. Probiotics decreased faecal viable count of Enterobacteriaceae and increased that of lactobacilli. Blueberry husks with or without probiotics lowered the proportion of butyric acid in distal colon, and decreased the haptoglobin levels. Probiotics mitigated hepatic injuries by decreasing parenchymal infiltration and the incidence of stasis and translocation

  14. Blueberry Husks and Probiotics Attenuate Colorectal Inflammation and Oncogenesis, and Liver Injuries in Rats Exposed to Cycling DSS-Treatment

    PubMed Central

    Håkansson, Åsa; Bränning, Camilla; Molin, Göran; Adawi, Diya; Hagslätt, Marie-Louise; Jeppsson, Bengt; Nyman, Margareta; Ahrné, Siv

    2012-01-01

    Long-term colonic inflammation promotes carcinogenesis and histological abnormalities of the liver, and colorectal tumours frequently arise in a background of dysplasia, a precursor of adenomas. Altered colonic microbiota with an increased proportion of bacteria with pro-inflammatory characteristics, have been implicated in neoplastic progression. The composition of the microbiota can be modified by dietary components such as probiotics, polyphenols and dietary fibres. In the present study, the influence of probiotics in combination with blueberry husks on colorectal carcinogenesis and subsequent liver damage was evaluated. Colorectal tumours were induced in rats by cyclic treatment with dextran sulphate sodium (DSS). Blueberry husks and a mixture of three probiotic strains (Bifidobacterium infantis DSM 15159, Lactobacillus gasseri, DSM 16737 and Lactobacillus plantarum DSM 15313) supplemented a basic diet fortified with oats. The condition of the rats was monitored using a disease activity index (DAI). A qualitative and quantitative histological judgement was performed on segments of distal colon and rectum and the caudate lobe of the liver. The formation of short-chain fatty acids, bacterial translocation, the inflammatory reaction and viable count of lactobacilli and Enterobaceriaceae were addressed. Blueberry husks with or without probiotics significantly decreased DAI, and significantly reduced the number of colonic ulcers and dysplastic lesions. With a decreased proportion of blueberry husk in the diet, the probiotic supplement was needed to achieve a significant decrease in numbers of dysplastic lesions. Probiotics decreased faecal viable count of Enterobacteriaceae and increased that of lactobacilli. Blueberry husks with or without probiotics lowered the proportion of butyric acid in distal colon, and decreased the haptoglobin levels. Probiotics mitigated hepatic injuries by decreasing parenchymal infiltration and the incidence of stasis and translocation

  15. Removal of Lead(II) Ions from Aqueous Solution Using L. Seed Husk Ash as a Biosorbent.

    PubMed

    Shi, Bingfang; Zuo, Weiyuan; Zhang, Jinlei; Tong, Haijuan; Zhao, Jinhe

    2016-05-01

    The removal of heavy metals, especially from wastewater, has attracted significant interest because of their toxicity, tendency to bioaccumulate, and the threat they pose to human life and the environment. Many low-cost sorbents have been investigated for their biosorption capacity toward heavy metals. However, there are no reports available on the removal of Pb(II) from aqueous solution by of L. seed husk ash. In this work, use of seed husk ash for the removal of Pb(II) from wastewater was investigated as a function of contact time and the initial pH of the solution. Kinetics and equilibrium constants were obtained from batch experiments. Our study shows that the adsorption process follows pseudo-second-order kinetics. Moreover, the Langmuir absorption model gave a better fit to the experimental data than the Freundlich equation. The maximum adsorption capacity of the husk ash was 263.10 mg g at 298 K and pH 5.0, and this is higher than the previously reported data obtained using other sorbents. The results obtained confirm that seed husk ash is an effective sorbent for the removal of Pb(II) from aqueous solution. Analysis of infrared spectra of the husk ash after absorption of Pb(II) suggested that OH, C=O, C-O, Si-O-Si, and O-Si-O groups were important for the Pb(II) ion removal. Moreover, practical tests on this biosorbent for Pb(II) removal in real wastewater samples successfully demonstrated that seed husk ash constitutes an efficient and cost-effective technology for the elimination of heavy metals from industrial effluent.

  16. Polymorphisms in LEP and NPY genes modify the response to soluble fibre Plantago ovata husk intake on cardiovascular risk biomarkers.

    PubMed

    Crescenti, Anna; Solà, Rosa; Valls, Rosa M; Anguera, Anna; Arola, Lluís

    2013-01-01

    The satiating effect of fibre consumption has been related to gut hormones, such as peptide YY and leptin. These peptides may also influence cardiovascular (CVD) risk biomarkers. Nevertheless, there is wide interindividual variation in metabolic responses to fibre consumption. The objective was to investigate differences in the effects of soluble fibre, in the form of Plantago ovata husk (Po-husk) treatment, on CVD risk biomarkers according to selected polymorphisms in genes related to satiety. The study was a multi-centred, double-blind, placebo-controlled, parallel and randomised trial in mild-moderate hypercholesterolaemic patients (age range: 43-67 years). Eight polymorphisms in three genes related to satiety (LEP, NPY and PYY) were identified in 178 participants; 88 patients in the placebo (microcrystalline cellulose 14 g/day) group and 90 in the Po-husk (14 g/day) group, which had added to a low-saturated-fat diet for 8 weeks. The CVD biomarkers measured included the following: lipid profile, blood pressure (BP), glucose, insulin, hs-CRP, oxidised LDL and IL-6. Relative to the placebo, Po-husk consumption lowered the plasma total cholesterol concentration by 3.3 % according to rs7799039 polymorphism in the LEP gene (p < 0.05). Furthermore, the Po-husk reduced systolic BP (mean [95 % CI]) by -8 mmHg (-14.16; -1.90) and hs-CRP by 24.9 % in subjects with the AA genotype of the rs16147 polymorphism in the NPY gene (32 % of our total population; p < 0.05), which remained significant after Bonferroni correction. In conclusion, polymorphisms in the LEP and NPY genes potentiate the response to Po-husk, particularly the effects on systolic BP and the hs-CRP plasma concentration.

  17. Transgenic cry1C(⁎) gene rough rice line T1C-19 does not change the host preferences of the non-target stored product pest, Rhyzopertha dominica (Fabricius) (Coleoptera: Bostrichidae), and its parasitoid wasp, Anisopteromalus calandrae (Howard) (Hymenoptera: Pteromalidae).

    PubMed

    Sun, Xiao; Yan, Miao-Jun; Zhang, Aijun; Wang, Man-Qun

    2015-10-01

    Rough rice grains are often stored for extended periods before they are used or consumed. However, during storage, the rough rice is vulnerable to insect infestation, resulting in significant economic loss. Previous studies have shown that volatiles cues, physical characteristics, and taste chemicals on the grains could be the important key behavior factors for storage insect pests to locate the hosts and select oviposition sites. It is also well known that the transgenic Bt rough rice line T1C-19, which expresses a cry1C(⁎) gene has a high resistance to Lepidoptera pests. However, there were no evidences to show the consequences of host preference for non-target insect pests after growing Bt transgenic rice. In this study, the potential key factors of Bt rough rice were investigated for their impacts on the behaviors of non-target pest lesser grain borer Rhyzopertha dominica, the main weevil pest of grain and its parasitic wasps Anisopteromalus calandrae, the natural enemy of the beetle. Both electronic nose and electronic tongue analyses showed that the parameters of Bt rough rice were analogous to those of the non-Bt rough rice. The volatile profiles of Bt and non-Bt rough rice examined by gas chromatographic mass spectrometry (GC-MS) were similar. For most volatile compounds, there were no significantly quantitative differences in compound quantities between Bt and non-Bt rough rice. The densities of sclereids and trichomes on the rough rice husk surface were statistically equal in Bt and non-Bt rough rice. The non-target pest, R. dominica, and its parasitoid wasp, A. calandrae, were attracted to both rough rice and could not distinguish the transgenic T1C-19 from the isogenic rough rice. These results demonstrated that Bt rough rice has no negative impacts on the host preference behaviors of non-target stored product pest R. dominica and its parasitoid A. calandrae.

  18. Breath methane in functional constipation: response to treatment with Ispaghula husk.

    PubMed

    Vega, A B; Perelló, A; Martos, L; García Bayo, I; García, M; Andreu, V; Abad, A; Barenys, M

    2015-07-01

    Colonic fermentation produces hydrogen (H2 ), and also produces methane (CH4 ) in subjects with methanogenic flora (M+). Methane production has been associated with chronic constipation (CC) and with changes in gut motility. To determine CH4 production in CC compared to controls, and to assess whether the therapeutic response to Ispaghula husk in CC differs between CH4 -producers and non-producers. Forty-eight patients with functional constipation or irritable bowel syndrome-constipation and 19 healthy age-and-sex-matched volunteers (HV) filled in a 1-week symptom diary and a dietary questionnaire. They then underwent a lactulose breath test (LBT) to measure H2 and CH4 production (peak and area under the time-concentration curve, AUC-) and a colonic transit time (CTT) assessment. In patients, measurements were repeated after a 4-week treatment with Ispaghula husk. Prevalence of M+ in patients was 60.5% vs 52.6% in HV (p = 0.37). Patients had significantly longer CTT and greater production of both H2 and CH4 during LBT. There was a significant correlation between CH4 production and CTT (r = 0.51; p = 0.07). Treatment response rate was similar for M+ and M- patients (58.3% vs 52.9%; p = 0.76) as were the increases in bowel movements and Bristol score, changes in abdominal discomfort and bloating. In M+, treatment reduced CTT (-10 ± 35 h; p = 0.029 vs baseline) and CH4 levels: peak CH4 (-13 ± 24 ppm; p = 0.014) and CH4 -AUC (-817 ± 3100 ppm/min; p = 0.04). Although CH4 production has been associated with CC pathophysiology, we found that CH4 status did not negatively affect the response to Ispaghula husk treatment. The measurement of CH4 levels as a biomarker tool for CC requires further appraisal. © 2015 John Wiley & Sons Ltd.

  19. Iron absorption from brown rice/brown rice-based meal and milled rice/milled rice-based meal.

    PubMed

    Trinidad, Trinidad P; Mallillin, Aida C; Sagum, Rosario S; Briones, Dave P; Encabo, Rosario R; Juliano, Bienvenido O

    2009-12-01

    Milled rice is the staple food among Filipinos and is mostly consumed three times a day. Rice as a source of iron could therefore have an important role in the existing 37% prevalence of iron-deficiency anemia in the country. Previous iron absorption studies in Filipinos from rice and rice-based meals were carried out on milled rice but no research was done on brown rice of the same variety. This leads to the hypothesis that brown rice may be better than milled rice in terms of iron content. To determine iron absorption from brown rice and brown rice-based meal, and from milled rice and milled rice-based meal of the same variety. The rice variety used in the study was F(2) seeds of PSB Rc72H. Iron absorption from brown/milled rice and brown/milled rice-based meals was determined in 12 healthy human subjects from the incorporation of radioisotopes of iron into erythrocytes 14 days after administration of the labeled rice/rice-based meals. The above samples were also analyzed for nutrient content, including dietary fiber, and iron. The iron content of brown rice was significantly higher (1.1 +/- 0.1 mg/100 g) than that of milled rice (0.6 +/- 0.1 mg/100 g). Brown rice has significantly greater amounts of total dietary fiber (5.4 +/- 0.4%) than milled rice (1.7 +/- 0.2%; P < 0.05). Both tannic acid and phytic acid contents in brown rice (56.9 +/- 3.2 mg/100 g and 290.1 +/- 18.0 mg/100 g, respectively) were significantly higher than those of milled rice (21.3 +/- 2.3 mg/100 g and 84.0 +/- 12.4 mg/100 g, respectively; P<0.05). The amount of iron absorbed from brown rice (0.13 +/- 0.02 mg) did not differ significantly from that from milled rice (0.14 +/- 0.02 mg). However, the amount from brown rice-based meal (0.36 +/- 0.04 mg) differed significantly from that from brown rice (P<0.05) as well as that from milled rice-based meal (0.35 +/- 0.03 mg) from that from milled rice (P<0.05). Moreover, brown rice-based meal did not differ significantly from milled rice-based meal

  20. Evidence from Social Service Enhancement Projects: Selected Cases from Norway's HUSK Project.

    PubMed

    Johannessen, Asbjorn; Eide, Solveig Botnen

    2015-01-01

    Through this article the authors describe the social service context of the HUSK (The University Research Program to Support Selected Municipal Social Service Offices) projects and briefly describe 10 of the 50 projects funded throughout the country. The welfare state context for the cases and the criteria for case selection are also provided. The 10 cases are organized into three categories that feature the role of dialogue, educational innovation, and service innovation. These cases provide the foundation for the analysis and implications located in the subsequent articles of the special issue.

  1. Practice-based research: the role of HUSK in knowledge development.

    PubMed

    Julkunen, Ilse

    2015-01-01

    Practice research involves curiosity about practice. It is about challenging complex practices through a critical and co-productive examination of concrete practices and how ideas are created, adopted, and spread. By involving the relational complexities within practice and by strengthening the relational and organizational linkage between research and practice, the relevance of research may transcend the process of generalizing and disseminating research findings. In this analysis, the author uses the theoretical approach of actor relations to analyze the HUSK projects in their efforts to develop new forms of collaboration between research, practice, education, and service users to build knowledge about improving the quality of social services.

  2. Innate immunity in rice

    PubMed Central

    Chen, Xuewei; Ronald, Pamela C.

    2011-01-01

    Advances in studies of rice innate immunity have led to the identification and characterization of host sensors encoding receptor kinases that perceive conserved microbial signatures. The non-RD domain, a newly recognized hallmark of these receptor kinases is highly expanded in rice (Oryza sativa) compared with Arabidopsis (Arabidopsis thaliana). Researchers have also identified a diverse array of microbial effectors from bacterial and fungal pathogens that triggers immune responses upon perception. These include both, effectors that indirectly target host Nucleotide binding site/Leucine rice repeat (NBS-LRR) proteins and transcription activator-like (TAL) effectors that directly bind promoters of host genes. Here we review the recognition and signaling events that govern rice innate immunity. PMID:21602092

  3. Rice (Oryza sativa L.) Seed Sterilization and Germination Enhancement via Atmospheric Hybrid Nonthermal Discharge Plasma.

    PubMed

    Khamsen, Natthaporn; Onwimol, Damrongvudhi; Teerakawanich, Nithiphat; Dechanupaprittha, Sanchai; Kanokbannakorn, Weerawoot; Hongesombut, Komsan; Srisonphan, Siwapon

    2016-08-03

    We designed a system to produce atmospheric hybrid cold-discharge plasma (HCP) based on microcorona discharge on a single dielectric barrier and applied it to inactivate microorganisms that commonly attach the rice seed husk. The cold-plasma treatment modified the surface of the rice seeds, resulting in accelerated germination and enhanced water imbibition. The treatment can operate under air-based ambient conditions without the need for a vacuum. The cold-plasma treatment completely inactivated pathogenic fungi and other microorganisms, enhancing the germination percentage and seedling quality. The final germination percentage of the treated rice seeds was ∼98%, whereas that of the nontreated seeds was ∼90%. Microcorona discharge on a single dielectric barrier provides a nonaggressive cold plasma that can be applied to organic materials without causing thermal and electrical damage. The hybrid nonthermal plasma is cost effective and consumes relatively little power, making it suitable for the surface sterilization and disinfection of organic and biological materials with large-scale compatibility.

  4. Total phenols, antioxidant potential and antimicrobial activity of walnut (Juglans regia L.) green husks.

    PubMed

    Oliveira, Ivo; Sousa, Anabela; Ferreira, Isabel C F R; Bento, Albino; Estevinho, Letícia; Pereira, José Alberto

    2008-07-01

    The total phenols content and antioxidant and antimicrobial activities were studied in walnut (Juglans regia L.) green husks aqueous extracts of five different cultivars (Franquette, Mayette, Marbot, Mellanaise and Parisienne). Total phenols content was determined by colorimetric assay and their amount ranged from 32.61 mg/g of GAE (cv. Mellanaise) to 74.08 mg/g of GAE t (cv. Franquette). The antioxidant capacity of aqueous extracts was assessed through reducing power assay, scavenging effects on DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals and beta-carotene linoleate model system. A concentration-dependent antioxidative capacity was verified in reducing power and DPPH assays, with EC50 values lower than 1 mg/mL for all the tested extracts. The antimicrobial capacity was screened against Gram positive and Gram negative bacteria, and fungi. All the extracts inhibited the growth of Gram positive bacteria, being Staphylococcus aureus the most susceptible one with MIC of 0.1 mg/mL for all the extracts. The results obtained indicate that walnut green husks may become important in the obtainment of a noticeable source of compounds with health protective potential and antimicrobial activity.

  5. Properties of whey protein isolate nanocomposite films reinforced with nanocellulose isolated from oat husk.

    PubMed

    Qazanfarzadeh, Zeinab; Kadivar, Mahdi

    2016-10-01

    Whey protein isolate (WPI)-based composite films with varying proportions of oat husk nanocellulose (ONC) obtained from acid sulfuric hydrolysis were prepared using a solution casting method. The obtained material after each step of the isolating cellulose, morphological and crystallinity of the ONC were studied by Fourier transform infrared (FTIR) spectroscopy, Scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The effect of ONC content (0, 2.5, 5 and 7.5wt% of WPI) on physical, mechanical and barrier properties of the nanocomposite were then evaluated. FTIR spectroscopy indicated the progressive removal of non-cellulosic components from the oat husk. SEM images showed the mean width of ONC was about 76nm and XRD analysis revealed the crystallinity increased after acid hydrolysis. The films prepared with up to 5wt% ONC showed the highest tensile strength, Young's modulus, solubility and the lowest elongation at break and moisture content. At high level (7.5wt%), tensile strength, Young's modulus and solubility of the films decreased and elongation at break and moisture content increased due to agglomeration of the fillers. Nevertheless, film transparency and water vapor permeability decreased with ONC incorporation.

  6. Influences of composted hazelnut husk on some physical properties of soils.

    PubMed

    Zeytin, Serhat; Baran, Abdullah

    2003-07-01

    Some physical properties of clay loam and sandy loam soils amended with hazelnut husk (HH) were investigated. HH collected from hazelnut trees were dried, ground and composted for four months. Before use the composted material obtained was separated to three different aggregate sizes, smaller than 0.84 mm, 0.84-2.38 mm and bigger than 2.38 mm. Then these fractions were mixed with soil samples, at 0%, 1%, 2%, 4% and 8% by weight. Huzelnut husk compost-soil mixtures were placed to plastic pots and kept in an incubator at 25+/-5 degrees C for 45 and 90 days. At the end of incubation periods, water stable aggregate (WSA), hydraulic conductivity, total porosity, aeration porosity and macro- and micro-pore percentages of the mixtures were determined. Results obtained showed that composted HH increased the WSA, hydraulic conductivity, total porosity and macro-pore percentage in both clay loam and sandy loam soils depending on the incubation time and aggregate sizes.

  7. Antimicrobial properties of Cocos nucifera (coconut) husk: An extrapolation to oral health.

    PubMed

    Jose, Maji; Cyriac, Maria B; Pai, Vidya; Varghese, Ipe; Shantaram, Manjula

    2014-07-01

    Brushing the teeth with fibrous husk of Cocos nucifera (coconut) is a common oral hygiene practice among people of rural areas of South India. However, the probable antimicrobial properties of this plant material against common oral pathogens have not been proved scientifically. Therefore, the present study was designed. Alcoholic extract of the husk of Cocos nucifera was prepared and the antimicrobial properties against common oral pathogens like cariogenic bacteria, periodontal pathogens, and candidal organisms were performed by the Agar Well Diffusion Method. The results obtained were then subjected to statistical analysis using One-Way Analysis of Variance (ANOVA) and the Tukey's Honestly Significant Difference (HSD). The alcoholic extract of Cocos nucifera showed a significant concentration-dependent antimicrobial activity, expressed as a zone of inhibition with respect to all tested organisms except Actinomyces species. The inhibitory effect was more significant, with a majority of cariogenic organisms and Candida, with a zone of inhibition ranging from 4.6 mm to 16.3 mm. However, the effect was lesser with Cocos nucifera compared to chlorhexidine. Minimum inhibitory concentration (MIC) ranged from 50 mg/ml to 75 mg/ml. Cocos nucifera has a significant inhibitory action against common oral pathogens, indicating the presence of highly effective antimicrobial compounds. Therefore, it is proved that its use can contribute to oral health to a great extent. Identification of these active compounds provides the scope for incorporating it into a modern oral care system, so as to control oral diseases.

  8. Bioremoval of cadmium from aqueous solution by black gram husk (Cicer arientinum).

    PubMed

    Saeed, Asma; Iqbal, Muhammed

    2003-08-01

    Husk of black gram (Cicer arientinum), a waste of no commercial value, was investigated as a new biosorbent of cadmium from low concentration aqueous solutions. With 99.99% sorption efficiency from 10mg l(-1) cadmium solution, the biomass required at saturation was 0.8 g mg(-1) cadmium. Biosorption was rapid and equilibrium was achieved in 30 min. Among the various desorbing agents tested, 99.89% cadmium recovery was achieved with 0.1M HCl. Sorption efficiency of cadmium during six biosorption-desorption cycles in batch operations declined, which was traceable to 39.0% black gram husk (bgh) weight loss. This decline was only 9.71% when compensated for biomass loss, which is comparable to 10.45% decline during six cycles in fixed bed column bioreactor in which biomass loss was only 5.98%. On plotting breakthrough curves it was noted that bgh in the fixed bed column was capable of bringing down cadmium concentration from 10 to 0.1 mg l(-1) in 35.5 l volume. Biosorption of cadmium was not effected in the presence of other cations. Comprehensive characterization of parameters indicate bgh to be an excellent material for biosorption of cadmium to treat wastewaters containing low concentration of the metal. As an agrowaste, the advantage of application of this material as a metal biosorbent in a fixed bed column bioreactor system, in comparison with those based on immobilized algae or biomass of algal, fungal and bacterial origin, is considered.

  9. Effect of dietary garlic bulb and husk on the physicochemical properties of chicken meat.

    PubMed

    Kim, Y J; Jin, S K; Yang, H S

    2009-02-01

    This study was carried out to compare the physicochemical and sensory properties of chicken thigh muscles from broilers fed different levels of garlic bulb (GB) and garlic husk (GH). Two hundred male Arbor Acre broiler chickens were fed either a control diet (based on corn and soybean meal) or the control diet supplemented with 2 and 4% of GB and GH powder for 5 wk. There were no differences among diets in moisture and ash contents. However, dietary supplementation with GB and GH resulted in significantly greater protein content and lower fat content in chicken thigh muscle compared with muscle from birds fed nonsupplemented diets (P<0.05). Increasing the level of garlic supplementation resulted in lower shear force and thiobarbituric acid reactive substances values (P<0.05). Dietary supplementation with garlic led to decreased total and low-density lipoprotein cholesterol levels in broiler blood, and the greatest level of garlic supplementation decreased saturated fatty acid and increased unsaturated fatty acid levels (%) in broiler thigh muscle (P<0.05). Sensory panelists recorded greater hardness and flavor scores to the samples with garlic dietary supplementation (P<0.05). These data suggest that supplementing broiler chicken diets with garlic can produce chicken meat with favorable lipid profiles and can enhance eating quality because sensory panels found that thigh meat from chickens fed a garlic-supplemented diet had better texture and flavor. Therefore, the treatment with the most significant effects in this study was that with the high level of garlic husk.

  10. A gastroretentive drug delivery system of lisinopril imbibed on isabgol-husk.

    PubMed

    Semwal, Ravindra; Semwal, Ruchi Badoni; Semwal, Deepak Kumar

    2014-01-01

    The gastroretentive drug delivery system is site-specific and allows the drug to remain in the stomach for a prolonged period of time so that it can be released in a controlled manner in gastrointestinal tract. The present study was carried out to develop a gastroretentive drug delivery system using isabgol as an excipient to prolong the residence time of the model drug lisinopril in the stomach. The gastroretentive ability of isabgol was increased by addition of NaHCO3 as a gas-generating agent while its mucoadhesive property was enhanced by incorporation of HPMC-K4M. The drug, NaHCO3 and HPMC-K3M were imbibed on isabgol-husk as per entrapment efficiency of the isabgol-husk. After drying, the product was filled in a hard gelatin capsule and evaluated for its buoyancy, mucoadhesive properties, swelling index and in vitro drug release. The lisinopril released through isabgol was delayed by 12 hours when compared to a preparation available on the market which released the complete drug in 0.5 hours. The drug release study of lisinopril from the formulation follows first order kinetics using a diffusion controlled mechanism. The results from the present study revealed that isabgol can be used as a potential excipient for the formulation of gastroretentive drug delivery systems in the near future.

  11. Pectin-based composite film: Effect of corn husk fiber concentration on their properties.

    PubMed

    Bernhardt, Dana C; Pérez, Carolina D; Fissore, Eliana N; De'Nobili, Maria D; Rojas, Ana M

    2017-05-15

    Considering the polysaccharide composition and 32% of crystallinity of the water insoluble fiber extracted from corn husk (CHF) agricultural residue, its filler performance as water vapor permeability (WVP) and mechanical modifier in edible films based on commercial low methoxyl pectin (LMP) was evaluated (0, 1, 3, 5, 8% concentrations). The 53-μm-CHF carried phenolics and carotenes, and composites showed antioxidant capacity. Homogeneous films with a continuous LMP matrix were obtained. The 5%-CHF composite showed the highest surface contact angle (44°) and tensile strength, without change in elongation, while WVP was decreased in the 3-8% CHF-LMP-films. The latter was ascribed to the CHF-filler crystallinity whereas the improvement in mechanical performance and contact angle was attributed to a CHF-interconnected network formed at 5%-CHF critical concentration. Corn husk residue can be utilized as a source of fibers for material development. Composites with enhanced performance can be an antioxidant strategy at food interfaces.

  12. Effect of silicate on arsenic fractionation in soils and its accumulation in rice plants.

    PubMed

    Wu, Chuan; Zou, Qi; Xue, Sheng-Guo; Pan, Wei-Song; Yue, Xu; Hartley, William; Huang, Liu; Mo, Jing-Yu

    2016-12-01

    Four rice genotypes, two hybrid and two indica, were selected to investigate the effects of silicate (Si) application on arsenic (As) accumulation and speciation in rice and As fractionation in soil. There were significant differences in root, straw and grain biomass among genotypes (p < 0.05), and Si application significantly increased root (p < 0.05) and grain biomass (p < 0.001). Silicate addition reduced the proportion of As associated with well-crystallized hydrous oxides of Fe and Al and residual phases, whilst increasing the proportions of specifically-sorbed As and As associated with amorphous and poorly-crystalline Fe and Al hydrous oxides. Furthermore, the results indicated that the fraction proportions of non-specifically sorbed, specifically-sorbed, and associated with amorphous and poorly-crystalline hydrous oxides of Fe and Al in rhizosphere soils, were greater than non-rhizosphere soils. Silicate application had a significant effect decreasing total As concentrations in root (p < 0.005), straw (p < 0.05) and husk (p < 0.001) of rice plants. The effect of Si on reducing As accumulation in rice leaves was revealed by SXRF. Indica genotypes transported and accumulated less As than hybrid genotypes. Both percentage and concentration of iAs were lower in indica genotype XFY-9 than in hybrid genotype XWX-12. Silicate reduced iAs and DMA by 21% and 58% in grain (polished) respectively. DMA may have a greater translocation capacity from straw to grain (polished) than inorganic As. The study provides the potential for understanding As uptake mechanisms in rice and mitigating the health risks posed by As contamination in paddy fields.

  13. Synthesis, characterization and catalytic activity of carbon-silica hybrid catalyst from rice straw

    NASA Astrophysics Data System (ADS)

    Janaun, J.; Safie, N. N.; Siambun, N. J.

    2016-07-01

    The hybrid-carbon catalyst has been studied because of its promising potential to have high porosity and surface area to be used in biodiesel production. Silica has been used as the support to produce hybrid carbon catalyst due to its mesoporous structure and high surface area properties. The chemical synthesis of silica-carbon hybrid is expensive and involves more complicated preparation steps. The presence of natural silica in rice plants especially rice husk has received much attention in research because of the potential as a source for solid acid catalyst synthesis. But study on rice straw, which is available abundantly as agricultural waste is limited. In this study, rice straw undergone pyrolysis and functionalized using fuming sulphuric acid to anchor -SO3H groups. The presence of silica and the physiochemical properties of the catalyst produced were studied before and after sulphonation. The catalytic activity of hybrid carbon silica acid catalyst, (H-CSAC) in esterification of oleic acid with methanol was also studied. The results showed the presence of silica-carbon which had amorphous structure and highly porous. The carbon surface consisted of higher silica composition, had lower S element detected as compared to the surface that had high carbon content but lower silica composition. This was likely due to the fact that Si element which was bonded to oxygen was highly stable and unlikely to break the bond and react with -SO3H ions. H-CSAC conversions were 23.04 %, 35.52 % and 34.2 7% at 333.15 K, 343.15 K and 353.15 K, respectively. From this research, rice straw can be used as carbon precursor to produce hybrid carbon-silica catalyst and has shown catalytic activity in biodiesel production. Rate equation obtained is also presented.

  14. Utilization of maize husk (Zea mays L.) as low-cost adsorbent in removal of iron from aqueous solution.

    PubMed

    Indah, S; Helard, D; Sasmita, A

    2016-01-01

    Adsorption of iron from aqueous solution by u