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1

Solvent wash solution  

DOEpatents

Process for removing diluent degradation products from a solvent extraction solution, which has been used to recover uranium and plutonium from spent nuclear fuel. A wash solution and the solvent extraction solution are combined. The wash solution contains (a) water and (b) up to about, and including, 50 volume percent of at least one-polar water-miscible organic solvent based on the total volume of the water and the highly-polar organic solvent. The wash solution also preferably contains at least one inorganic salt. The diluent degradation products dissolve in the highly-polar organic solvent and the organic solvent extraction solvent do not dissolve in the highly-polar organic solvent. The highly-polar organic solvent and the extraction solvent are separated.

Neace, James C. (Blackville, SC) [Blackville, SC

1986-01-01

2

Solvent wash solution  

DOEpatents

A process is claimed for removing diluent degradation products from a solvent extraction solution, which has been used to recover uranium and plutonium from spent nuclear fuel. A wash solution and the solvent extraction solution are combined. The wash solution contains (a) water and (b) up to about, and including, 50 vol % of at least one-polar water-miscible organic solvent based on the total volume of the water and the highly-polar organic solvent. The wash solution also preferably contains at least one inorganic salt. The diluent degradation products dissolve in the highly-polar organic solvent and the organic solvent extraction solvent do not dissolve in the highly-polar organic solvent. The highly-polar organic solvent and the extraction solvent are separated.

Neace, J.C.

1984-03-13

3

Potential of activated carbon to recover randomly-methylated-?-cyclodextrin solution from washing water originating from in situ soil flushing.  

PubMed

Despite the overall high efficacy of cyclodextrins to accelerate the treatment of soil aquifer remediation by in-situ soil flushing, the use in practice remains limited because of the high costs of cyclodextrin and high concentrations needed to significantly reduce the treatment time. The current study tested the potential of activated carbon to treat washing water originating from soil flushing in order to selectively separate hydrocarbon contaminants from washing water containing cyclodextrin and subsequently reuse the cyclodextrin solution for reinfiltration. A high recovery of the cyclodextrin from the washing water would reduce the costs and would make the technique economically feasible for soil remediation. This study aimed to investigate whether cyclodextrin can pass through the activated carbon filter without reducing the cyclodextrin concentration when the contaminated washing water is treated and whether the presence of cyclodextrin negatively affects the purification potential of activated carbon to remove the organic pollutants from the pumped soil water. Lab-scale column experiments showed that with the appropriate activated carbon 100% of cyclodextrin (randomly-methylated-?-cyclodextrin) can be recovered from the washing water and that the effect on the efficiency of activated carbon to remove the hydrocarbon contaminants remains limited. These results show that additional field tests are useful to make in-situ soil flushing with cyclodextrin both a technical and an economical interesting technique. These results might stimulate the application of cyclodextrin in soil treatment technology. PMID:24325845

Sniegowski, K; Vanhecke, M; D'Huys, P-J; Braeken, L

2014-07-01

4

Recovery of plutonium from solvent wash solutions  

SciTech Connect

A number of potential alternatives to the acid hydrolysis recovery of Pu were investigated. The most promising alternative for short-term use appears to be an anion exchange process that would eliminate the long boiling times and the multiple-pass concentration steps needed with the solvent extraction process because it separates the Pu from the dibutyl phosphate (DBP) while at the same time concentrating the Pu. However, restart of the Primary Recovery Column (PRC) to process this solution would require significant administrative effort. The original boiling recovery by acid hydrolysis followed by solvent extraction is probably the most expedient way to process the Pu-DBP-carbonate solution currently stored in tank 13.5 even with its long processing times and dilute product concentration. Anion exchange of a heat stabilized acidified solution is a more efficient process, but requires restart of the PRC. Extended-boiling acid hydrolysis or anion exchange of a heat stabilized acidified solution provide two well developed alternatives for recovery of the Pu from the tank 13.5 carbonate. Further work defining additional recovery processes is not planned at this time.

Kyser, E.A.

1992-03-31

5

Soil washing using various nonionic surfactants and their recovery by selective adsorption with activated carbon.  

PubMed

The performance of activated carbon in soil washing and subsequent selective adsorption for surfactant recovery from the washed solution was investigated. Sandy loam soil contaminated with phenanthrene at 200 mg kg(-1) was washed with four different nonionic surfactants: Tween 40, Tween 80, Brij 30 and Brij 35. The efficiency of soil washing was highest when using Brij 30 with the highest solubilizing ability for phenanthrene and low adsorption onto soil. In the selective adsorption step, surfactant recovery was quite effective for all surfactants ranging from 85.0 to 89.0% at 1 g L(-1) of activated carbon (Darco 20-40 mesh). Phenanthrene removal from the solution washed with Brij 30 was only 33.9%, even though it was 54.1-56.4% with other surfactants. The selectivity was larger than 7.02 except for Brij 30 (3.60). The overall performance considering both the washing and surfactant recovery step was effective when using Tween 80 and Brij 35. The results suggest that higher solubilizing ability of surfactants is a requirement for soil washing but causes negative effects on phenanthrene removal in the selective adsorption. Therefore, if a surfactant recovery process by selective adsorption is included in soil remediation by washing, the overall performance including the two steps should be considered for properly choosing the surfactant. PMID:18006231

Ahn, C K; Kim, Y M; Woo, S H; Park, J M

2008-06-15

6

Changes in the Bacterial Flora of Skin of Processed Broiler Chickens Washed in Solutions of Salicylic Acid  

Microsoft Academic Search

Changes in the number of bacteria recovered from the skin of processed broilers after each of five consecutive washings in salicylic acid (SA) solutions was examined. Skin samples from commercially processed broiler carcasses were divided into 3 groups and washed in distilled water (control), 10% SA, or 20% SA by agitating skin in wash solutions in a Stomacher laboratory blender.

A. Hinton Jr.; J. A. Cason

2007-01-01

7

Aquifer washing by micellar solutions: 2. DNAPL recovery mechanisms for an optimized alcohol–surfactant–solvent solution  

Microsoft Academic Search

A large sand column experiment is used to illustrate the principles of complex organic contaminants (DNAPL) recovery by a chemical solution containing an alcohol (n-butanol), a surfactant (Hostapur SAS), and two solvents (d-limonene and toluene). The washing solution is pushed by viscous polymer solutions to keep the displacement stable. The main NAPL recovery mechanisms identified are: (1) immiscible displacement by

Richard Martel; René Lefebvre; Pierre J Gélinas

1998-01-01

8

Mathematical evaluation of activated carbon adsorption for surfactant recovery in a soil washing process.  

PubMed

The performances of various soil washing processes, including surfactant recovery by selective adsorption, were evaluated using a mathematical model for partitioning a target compound and surfactant in water/sorbent system. Phenanthrene was selected as a representative hazardous organic compound and Triton X-100 as a surfactant. Two activated carbons that differed in size (Darco 20-40 mesh and >100 mesh sizes) were used in adsorption experiments. The adsorption isotherms of the chemicals were used in model simulations for various washing scenarios. The optimal process conditions were suggested to minimize the dosage of activated carbon and surfactant and the number of washings. We estimated that the requirement of surfactant could be reduced to 33% of surfactant requirements (from 265 to 86.6g) with a reuse step using 9.1g activated carbon (>100 mesh) to achieve 90% removal of phenanthrene (initially 100mg kg-soil(-1)) with a water/soil ratio of 10. PMID:18384951

Ahn, Chi K; Lee, Min W; Lee, Dae S; Woo, Seung H; Park, Jong M

2008-12-15

9

Modified sodium diuranate process for the recovery of uranium from uranium hexafluoride transport cylinder wash solution  

NASA Astrophysics Data System (ADS)

Uranium hexafluoride (UF6) containment cylinders must be emptied and washed every five years in order to undergo recertification, according to ANSI standards. During the emptying of the UF6 from the cylinders, a thin residue, or heel, of UF6 is left behind. This heel must be removed in order for recertification to take place. To remove it, the inside of the containment cylinder is washed with acid and the resulting solution generally contains three or four kilograms of uranium. Thus, before the liquid solution can be disposed of, the uranium must be separated. A modified sodium diuranate (SDU) uranium recovery process was studied to support development of a commercial process. This process was sought to ensure complete uranium recovery, at high purity, in order that it might be reused in the nuclear fuel cycle. An experimental procedure was designed and carried out in order to verify the effectiveness of the commercial process in a laboratory setting. The experiments involved a small quantity of dried UO2F2 powder that was dosed with 3wt% FeF3 and was dissolved in water to simulate the cylinder wash solution. Each experiment series started with a measured amount of this powder mixture which was dissolved in enough water to make a solution containing about 120 gmU/liter. The experiments involved validating the modified SDU extraction process. A potassium diuranate (KDU) process was also attempted. Very little information exists regarding such a process, so the task was undertaken to evaluate its efficacy and determine whether a potassium process yields any significant differences or advantages as compared to a sodium process. However, the KDU process ultimately proved ineffective and was abandoned. Each of the experiments was organized into a series of procedures that started with the UO2F2 powder being dissolved in water, and proceeded through the steps needed to first convert the uranium to a diuranate precipitate, then to a carbonate complex solution, and finally to a uranyl peroxide (UO4) precipitate product. Evaluation of operating technique, uranium recovery efficiency, and final product purity were part of each experiment. Evaluation of a technique for removing fluoride from the diuranate precipitation byproduct filtrate using granular calcite was also included at the end of the uranium recovery testing. It was observed that precipitation of sodium diuranate (SDU) was very nearly complete at a pH of 11-12, using room temperature conditions. Uranium residuals in the filtrate ranged from 3.6 - 19.6 ppm, meaning almost complete precipitation as SDU. It was postulated and then verified that a tailing reaction occurs in the SDU precipitation, which necessitates a digestion period of about 2 hours to complete the precipitation. Further, it was shown, during this phase of the process, that a partial precipitation step at pH 5.5 did not adequately separate iron contamination due to an overlap of uranium and iron precipitations at that condition. Carbonate extraction of the SDU required an extended (3-4 hours) digestion at 40°C and pH 7-8 to complete, with sodium bicarbonate found to be the preferred extractant. The carbonate extraction was also proven to successfully separate the iron contamination from the uranium. Potassium-based chemistry did produce a potassium diuranate (KDU) analogue of SDU, but the subsequent carbonate extraction using either potassium bicarbonate or potassium carbonate proved to be too difficult and was incomplete. The potassium testing was terminated at this step. The uranyl peroxide precipitation was found to operate best at pH 3.5 - 4.0, at room temperature, and required an expected, extended digestion period of 8 -10 hours. The reaction was nearly complete at those conditions, with a filtrate residual ranging from 2.4 to 36.8 ppmU. The uranyl peroxide itself was very pure, with impurity averages at a very low 0.8 ppmNa and 0.004 ppmFe. ASTM maximum levels are 20 ppmNa and 150 ppmFe. Fluoride removal from the SDU precipitation filtrate required multiple passes of the solution through a calcite

Meredith, Austin Dean

10

Fresh-cut product sanitation and wash water disinfection: problems and solutions.  

PubMed

It is well known that fresh-cut processors usually rely on wash water sanitizers to reduce microbial counts in order to maintain quality and extend shelf-life of the end product. Water is a useful tool for reducing potential contamination but it can also transfer pathogenic microorganisms. Washing with sanitizers is important in fresh-cut produce hygiene, particularly removing soil and debris, but especially in water disinfection to avoid cross-contamination between clean and contaminated product. Most of the sanitizing solutions induce higher microbial reduction after washing when compared to water washing, but after storage, epiphytic microorganisms grow rapidly, reaching similar levels. In fact, despite the general idea that sanitizers are used to reduce the microbial population on the produce, their main effect is maintaining the microbial quality of the water. The use of potable water instead of water containing chemical disinfection agents for washing fresh-cut vegetables is being advocated in some European countries. However, the problems of using an inadequate sanitizer or even none are considered in this manuscript. The need for a standardized approach to evaluate and compare the efficiency of sanitizing agents is also presented. Most new alternative techniques accentuate the problems with chlorine suggesting that the industry should move away from this traditional disinfection agent. However, the use of chlorine based sanitizers are presented as belonging to the most effective and efficient sanitizers when adequate doses are used. In this review improvements in water disinfection and sanitation strategies, including a shower pre-washing step and a final rinse of the produce, are suggested. PMID:19539390

Gil, Maria I; Selma, Maria V; López-Gálvez, Francisco; Allende, Ana

2009-08-31

11

Hand held brush for delivering multiple foamable wash/wax solutions  

US Patent & Trademark Office Database

The present invention is directed to a hand held brush for delivering multiple foamable wash/wax solutions and designed to effectively and aesthetically wax the vehicle which includes a generally hollow elongated shaft having a first end and a second end and a plurality of veins extending thought the shaft, a head connected to the first end of the shaft and having a plurality separate compartments and a plurality of aperture surfaces formed within the head, a first of the compartments communicating with a first of the veins and a first of the aperture surfaces, and a second of the compartments communicating with a second of the veins and a second of the aperture surfaces, and the head further having means connected to the head for aiding application of the foamable wash/wax solutions.

1997-12-09

12

Enhanced Inactivation of Salmonella and Pseudomonas Biofilms on Stainless Steel by Use of T-128, a Fresh-Produce Washing Aid, in Chlorinated Wash Solutions  

PubMed Central

The effect of the washing aid T-128 (generally recognized as safe [GRAS] formulation, composed mainly of phosphoric acid and propylene glycol) on inactivation of Salmonella and Pseudomonas populations in biofilms on stainless steel was evaluated under conditions of increasing organic matter loads in chlorinated wash solutions dominated by hypochlorous acid. Biofilms were formed statically on stainless steel coupons suspended in 2% lettuce extract after inoculation with Salmonella enterica serovar Thompson or Newport or with Pseudomonas fluorescens. Coupons with biofilms were washed in chlorine solutions (0, 0.5, 1, 2, 5, 10, or 20 mg/liter at pH 6.5, 5.0 and 2.9), with or without T-128, and with increasing loads of organic matter (0, 0.25, 0.5, 0.75, or 1.0% lettuce extract). Cell populations on coupons were dispersed using intermittent, pulsed ultrasonication and vortexing and enumerated by colony counts on XLT-4 or Pseudomonas agars. Cell responses to fluorescent viability staining of biofilm treatment washing solutions were examined using confocal laser scanning microscopy. Results showed that 0.1% T-128 (without chlorine) reduced P. fluorescens biofilm populations by 2.5 log10 units but did not reduce Salmonella populations. For both Salmonella and Pseudomonas, the sanitizing effect of free chlorine (1.0 to 5.0 mg/liter) was enhanced (P < 0.05) when it was combined with T-128. Application of T-128 decreased the free chlorine depletion rate caused by increasing organic matter in wash waters and significantly (P < 0.05) augmented inactivation of bacteria in biofilms compared to treatments without T-128. Image analysis of surfaces stained with SYTO and propidium iodide corroborate the cultural assay results showing that T-128 can aid in reducing pathogen viability in biofilms and thus can aid in sanitizing stainless steel contact surfaces during processing of fresh-cut produce.

Shen, Cangliang; Luo, Yaguang; Nou, Xiangwu; Bauchan, Gary; Zhou, Bin; Wang, Qin

2012-01-01

13

Effect of number and washing solutions on functional properties of surimi-like material from duck meat.  

PubMed

Duck meat is less utilized than other meats in processed products because of limitations of its functional properties, including lower water holding capacity, emulsion stability, and higher cooking loss compared with chicken meat. These limitations could be improved using surimi technology, which consists of washing and concentrating myofibrillar protein. In this study, surimi-like materials were made from duck meat using two or three washings with different solutions (tap water, sodium chloride, sodium bicarbonate, and sodium phosphate buffer). Better improvement of the meat's functional properties was obtained with three washings versus two washings. Washing with tap water achieved the highest gel strength; moderate elevation of water holding capacity, pH, lightness, and whiteness; and left a small amount of fat. Washing with sodium bicarbonate solution generated the highest water holding capacity and pH and high lightness and whiteness values, but it resulted in the lowest gel strength. Processing duck meat into surimi-like material improves its functional properties, thereby making it possible to use duck meat in processed products. PMID:24493882

Ramadhan, Kurnia; Huda, Nurul; Ahmad, Ruzita

2014-02-01

14

Physicochemical and microbial quality of stored green slender pepper treated with different washing solutions and packaging films.  

PubMed

The effects of different washing solutions and packaging films on textural, biochemical and microbial quality of green slender peppers (Capsicum annuum L.) were evaluated. Fresh pepper samples were packaged either in 35?µm polypropylene or polyethylene bag without washing or after washing in tap water (TW), 100-ppm chlorine solution, 0.5% calcinated calcium solution followed by 25% ethanol rinsing (CC+E) and 1% citric acid solution followed by 50% ethanol spray (CA+E) and then stored at 10? for 4 weeks. Significant differences were found in gas composition between the two packaging films. Changes in skin puncture force, hue angle, soluble solid content, titratable acidity and pH were statistically insignificant. Chlorophyll a, chlorophyll b and total chlorophyll content declined significantly (P?washing treatments compared to unwashed sample except in TW. Yeast and mold count of chlorine and CC+E-treated samples were lower than other treatments. Samples of these two treatments also received marketable limit of visual quality scores until 4 weeks of storage in polypropylene film. Results suggest that CC+E could be a potential sanitizer and alternative to chlorine washing and polypropylene film would provide a little better advantage than polyethylene for green slender pepper. PMID:23733826

Chandra, Dulal; Kim, Ji Gang; Kim, Yong Phil

2014-03-01

15

Formulating essential oil microemulsions as washing solutions for organic fresh produce production.  

PubMed

Applications of plant-derived organic essential oils (EOs) as antimicrobials for post-harvest produce operations are limited by their low water solubility. To dissolve EOs in water, microemulsions were studied using two surfactants permitted for organic production, sucrose octanoate ester (SOE) and soy lecithin that were mixed at various mass ratios before dilution with water to 40% w/w. EOs were then mixed with the surfactant solution by hand shaking. Based on visual transparency, intermediate lecithin:SOE mass ratios favoured the formation of microemulsions, e.g., up to 4.0% clove bud oil at ratios of 2:8 and 3:7, and 4.0% cinnamon bark oil and 3.0% thyme oil at ratios of 2:8 and 1:9, respectively. Microemulsions with intermediate lecithin:SOE mass ratios had a relatively low viscosity and better ability to wet fresh produce surfaces. The microemulsions established in this work may be used as washing solutions to enhance the microbial safety of organic fresh produce. PMID:25038656

Zhang, Linhan; Critzer, Faith; Davidson, P Michael; Zhong, Qixin

2014-12-15

16

Recovery of bacteria from broiler carcasses after spray washing with acidified electrolyzed water or sodium hypochlorite solutions.  

PubMed

A study was conducted to investigate the effects of spray washing broiler carcasses with acidified electrolyzed oxidizing water (EO) or sodium hypochlorite (HOCl) solutions for 5, 10, or 15 s. Commercial broiler carcasses were contaminated with 0.1 g of broiler cecal contents inoculated with 10(5) cells of Campylobacter and 10(5) cells of nalidixic acid-resistant Salmonella. Numbers of bacteria recovered from unwashed control carcasses were 6.7, 5.9, 6.3, and 3.9 log(10) cfu/mL for total aerobic bacteria, Escherichia coli, Campylobacter, and Salmonella, respectively. Washing in either EO (50 mg/L of sodium hypochlorite, pH 2.4, oxidation reduction potential of 1,180 mV) or HOCl (50 mg/L of sodium hypochlorite, pH 8.0) significantly reduced the levels of bacteria recovered from carcasses (P < 0.05). Carcasses washed with EO had slightly lower levels of total aerobic bacteria (0.3 log(10) cfu/mL) and E. coli (0.2 log(10) cfu/mL) than HOCl-treated carcasses; however, populations of Campylobacter and Salmonella were comparable after washing in either solution. Increasing the carcass washing time from 5 to 10 s lowered the levels of total aerobic bacteria (6.1 vs. 5.8 log(10) cfu/mL), E. coli (4.6 vs. 4.1 log(10) cfu/mL), Campylobacter (5.2 vs. 4.2 log(10) cfu/mL), and Salmonella (2.0 vs. 1.2 log(10) cfu/mL), but no further microbiological reductions occurred when washing time was extended from 10 to 15 s. Data from the present study show that washing poultry carcasses with EO is slightly better (total aerobic bacteria and E. coli) or equivalent to (Campylobacter and Salmonella) washing with HOCl. Washing broiler carcasses for a period equivalent to 2 inside-outside bird washers (10 s) provided greater reductions in carcass bacterial populations than periods simulating 1 (5 s) or 3 inside-outside bird washers (15 s). PMID:17878456

Northcutt, J; Smith, D; Ingram, K D; Hinton, A; Musgrove, M

2007-10-01

17

Hand Washing  

MedlinePLUS

... or from animals and animal waste. Continue Defensive Hand Washing Did you know that an estimated 1 out ... American Society for Microbiology did a survey of hand washing. They asked people questions about their hand-washing ...

18

Ketoconazole or clotrimazole solution wash as a prophylaxis in management and prevention of fungal infection: a comparative study.  

PubMed

The incidence of fungal infections has increased at an alarming rate in the past two decades. Topical Ketoconazole and Clotrimazole solutions are used to stop growth of fungus like Dermatophytes, Candidiasis and Pityrosporum. The objective of this study is to assess the effectiveness of prophylactic Ketoconazole or Clotrimazole solution wash in patients with fungal infections. Hundred patients (aged 10-60 yrs) with different fungal infections (Candida, Tinea, Pityriasis) were included. The study groups were divided into intervention group and control group. The Intervention group was given 5 weeks prophylactic Ketoconazole/Clotrimazole shampoo wash along with antifungal treatment whereas the control group was given only antifungal treatment without prophylaxis. All the patients were assessed at 1, 3 and 6 months interval to find out the response and recurrence. After one month of treatment 96% of patients in the intervention group and 60% of patients in the control group were completely cured. The recurrence rate after 3 mths of treatment was 4% in the intervention group and 40% in the control group. After 6 months the recurrence rate was 4% in the intervention group and 60% in the control group. The most common problem with fungal infections is the recurrence. Use of prophylactic antifungal (Ketoconazole/Clotrimazole) wash for some period of time along with antifungal treatment minimizes the chances of recurrence. PMID:24592790

Shrestha, S; Jha, A K; Pathak, D Thapa; Kharel, C Bhattarai; Basukala, S M

2013-03-01

19

A soft-solution process for recovering rare metals from metal/alloy-wastes by grinding and washing with water.  

PubMed

We have developed a novel process for recovering metals from alloy-wastes by using a mechanochemical (MC) reaction. The process consists of co-grinding both alloy and polyvinyl chloride (PVC) samples, followed by washing with water and filtration. The co-grinding of the wastes causes a solid-state MC reaction to form metal chlorides and hydrocarbon in the product. The former products are soluble in water, so they can be recovered from the wastes by washing with water, followed by filtration. The PVC waste plays a significant role as a chlorine source in the MC reaction. After filtration, the solid residue can be used as a fuel, due to the absence of chlorine in the product, and the filtrate is subjected to hydrometallurgical process to extract metals from the solution. PMID:16621272

Zhang, Qiwu; Saeki, Shu; Tanaka, Yasumitsu; Kano, Junya; Saito, Fumio

2007-01-31

20

Properties improvement of paper mill sludge-based granular activated carbon fillers for fluidized-bed bioreactor by bentonite (Na) added and acid washing.  

PubMed

Properties improvement of paper mill sludge (PMS) based granular activated carbon fillers for fluidized-bed bioreactor (FBBR) was investigated in this study. Bentonite (Na) powders were blended in the dewatered paper mill sludge powders to strengthen the abrasion resistance strength of the fillers. Different acid washing treatments were studied to produce FBBR fillers with optimum performance. The results indicated that granulation was easy and the abrasion resistance strength of the fillers increased by 15% with 8 wt% of bentonite (Na) added. Acid washing treatment prior to activation had a better effect on the removal of Fe than post-activation acid washing treatment. HCl was the most appropriate acid during the acid washing treatment. The optimum acid washing treatment was carried out prior to activation with 2M HCl soaking for 6h. After acid washing treatment, the fillers with grain density of 1170 kg/m(3), specific surface area of 176 m(2)/g were obtained. PMID:21968120

Li, Yanjie; Yue, Qinyan; Li, Wenhong; Gao, Baoyu; Li, Jinze; Du, Jiadan

2011-12-15

21

SOIL WASHING TREATMENT  

EPA Science Inventory

Soil washing is a water-based process for mechanically scrubbing soils ex-situ to remove undesirable contaminants. he process removes contaminants from soils in one of two ways: by dissolving or suspending them in the wash solution (which is later treated by conventional wastewat...

22

High yield incorporation and washing properties of halides incorporated into single walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

We describe here the high yield filling (i.e. >50%) of single walled nanotubes (SWNTs) with a variety of halides, achieved according to various modified filling procedures. Both bundles and discrete SWNTs can be filled continuously up to lengths of several hundred nm, often with filling yields approaching 60-70% or better. In addition some high yield filled SWNTs were subjected to long-term washing in either boiling or room temperature. aqueous media, which does not remove the filling from the tubules, but enables effective removal of water-soluble extraneous materials .

Brown, G.; Bailey, S. R.; Novotny, M.; Carter, R.; Flahaut, E.; Coleman, K. S.; Hutchison, J. L.; Green, M. L. H.; Sloan, J.

23

Natural laccase mediators separated from water-washed solution of steam exploded corn straw by nanofiltration and organic solvent fractionation.  

PubMed

Artificially synthetic mediators of laccase had the limitation of high cost and possible toxicity. The separation of natural laccase mediators from water-washed solution (WWS) of steam exploded corn straw (SECS) was studied using nano-filtration and successive organic solvents extraction. Results indicated that the UV absorption intensity of nano-filtrated WWS was significantly enhanced. The UV absorption intensity of each extractive from WWS could be ranked as ether extractive (EE)>ethyl acetate extractive (EAE)>chloroform extractive (CE). Decoloration of crystal violet catalyzed by laccase/EE was higher than that by laccase/ABTS, which was 66.95% and 61.9% at 8h, respectively. All the decoloration rates of malachite green at 60min using EE, EAE and ABTS as mediator were both more than 80%. This research would benefit for broaden the source of laccase mediator and reduce the using cost of laccase/mediator system. PMID:24513027

Qiu, Weihua; Zhang, Wenyan; Chen, Hongzhang

2014-03-01

24

Influence of particle size distribution, organic carbon, pH and chlorides on washing of mercury contaminated soil.  

PubMed

Feasibility of soil washing to remediate Hg contaminated soil was studied. Dry sieving was performed to evaluate Hg distribution in soil particle size fractions. The influence of dissolved organic matter and chlorides on Hg dissolution was assessed by batch leaching tests. Mercury mobilization in the pH range of 3-11 was studied by pH-static titration. Results showed infeasibility of physical separation via dry sieving, as the least contaminated fraction exceeded the Swedish generic guideline value for Hg in soils. Soluble Hg did not correlate with dissolved organic carbon in the water leachate. The highest Hg dissolution was achieved at pH 5 and 11, reaching up to 0.3% of the total Hg. The pH adjustment was therefore not sufficient for the Hg removal to acceptable levels. Chlorides did not facilitate Hg mobilization under acidic pH either. Mercury was firmly bound in the studied soil thus soil washing might be insufficient method to treat the studied soil. PMID:24873713

Xu, Jingying; Kleja, Dan B; Biester, Harald; Lagerkvist, Anders; Kumpiene, Jurate

2014-08-01

25

PROCESSING, PRODUCTS, AND FOOD SAFETY Recovery of Bacteria from Broiler Carcasses after Spray Washing with Acidified Electrolyzed Water or Sodium Hypochlorite Solutions  

Microsoft Academic Search

A study was conducted to investigate the effects of spray washing broiler carcasses with acidified electrolyzed oxidizing water (EO) or sodium hypochlorite (HOCl) solutions for 5, 10, or 15 s. Commercial broiler carcasses were contaminated with 0.1 g of broiler cecal contents inoculated with 10 5 cells of Campylobacter and 10 5 cells of nalidixic acid-resistant Salmonella. Numbers of bacteria

J. Northcutt; D. Smith; K. D. Ingram; A. Hinton Jr.; M. Musgrove

26

Recovery of toxic metal ions from washing effluent containing excess aminopolycarboxylate chelant in solution.  

PubMed

Aminopolycarboxylate chelants (APCs) are extremely useful for a variety of industrial applications, including the treatment of toxic metal-contaminated solid waste materials. Because non-toxic matrix elements compete with toxic metals for the binding sites of APCs, an excess of chelant is commonly added to ensure the adequate sequestration of toxic metal contaminants during waste treatment operations. The major environmental impacts of APCs are related to their ability to solubilize toxic heavy metals. If APCs are not sufficiently eliminated from the effluent, the aqueous transport of metals can occur through the introduction of APCs into the natural environment, increasing the magnitude of associated toxicity. Although several techniques that focus primarily on the degradation of APCs at the pre-release step have been proposed, methods that recycle not only the processed water, but also provide the option to recover and reuse the metals, might be economically feasible, considering the high costs involved due to the chelants used in metal ion sequestration. In this paper, we propose a separation process for the recovery of metals from effluents that contain an excess of APCs. Additionally, the option of recycling the processed water using a solid phase extraction (SPE) system with an ion-selective immobilized macrocyclic material, commonly known as a molecular recognition technology (MRT) gel, is presented. Simulated effluents containing As(V), Cd(II), Cr(III), Pb(II) or Se(IV) in the presence of APCs at molar ratios of 1:50 in H2O were studied with a flow rate of 0.2 mL min(-1). The 'captured' ions in the SPE system were quantitatively eluted with HNO3. The effects of solution pH, metal-chelant stability constants and matrix elements were assessed. Better separation performance for the metals was achieved with the MRT-SPE compared to other SPE materials. Our proposed technique offers the advantage of a non-destructive separation of both metal ions and chelants compared to conventional treatment options for such effluents. PMID:21767860

Hasegawa, Hiroshi; Rahman, Ismail M M; Nakano, Masayoshi; Begum, Zinnat A; Egawa, Yuji; Maki, Teruya; Furusho, Yoshiaki; Mizutani, Satoshi

2011-10-15

27

Patterned forests of vertically-aligned multiwalled carbon nanotubes using metal salt catalyst solutions.  

PubMed

A simple method for producing patterned forests of multiwalled carbon nanotubes (MWCNTs) is described. An aqueous metal salt solution is spin-coated onto a substrate patterned with photoresist by standard methods. The photoresist is removed by acetone washing leaving the acetone-insoluble catalyst pattern on the substrate. Dense forests of vertically aligned (VA) MWCNTs are grown on the patterned catalyst layers by chemical vapour deposition. The procedures have been demonstrated by growing MWCNT forests on two substrates: silicon and conducting graphitic carbon films. The forests adhere strongly to the substrates and when grown directly on carbon film, offer a simple method of preparing MWCNT electrodes. PMID:23646807

Garrett, David J; Flavel, Benjamin S; Baronian, Keith H R; Downard, Alison J

2013-01-01

28

Washing Dishes  

NSDL National Science Digital Library

This experiment is about contaminiation. Learners will go through a series of steps in which they will test and observe how detergent breaks up contamination in a guided inquiry. Following this they will complete an open inquiry in which they ask questions about variables in washing dishes and design and conduct a test to answer these questions. Includes a teacher's guide and students handouts. Video and audio clips are provided. This lesson 4 of 10 from the Dynamic Design: The Cleanroom module.

29

Adsorption Characteristics of 2,4-Dichlorophenoxyacetic Acid (2,4-D) from Aqueous Solution on Powdered Activated Carbon  

Microsoft Academic Search

The removal of 2,4-dichlorophenoxyacetic acid (2,4-D), one of the most commonly used phenoxy acid herbicides, from aqueous solution was studied by using acid-washed powdered activated carbon (PAC) as an adsorbent in a batch system. Adsorption equilibrium, kinetics, and thermodynamics were investigated as a function of initial pH, temperature, and initial 2,4-D concentration. Powdered activated carbon exhibited the highest 2,4-D uptake

Z. AKSU; E. KABASAKAL

2005-01-01

30

Part 2. Comparison of emergency washing solutions in 70% hydrofluoric acid-burned human skin in an established ex vivo explants model  

PubMed Central

Background: Hydrofluoric acid (HF) is a small and partially dissociated acid (pKa 3.2), able to deeply penetrate into human skin in addition to the corrosiveness of the hydrogen ion (H+) and the toxicity of the fluoride ion (F-). However, there has been a lack of experimental studies to objectively characterize the results of human HF skin exposure decontamination. Methodology/principal findings: A previously established experimental method using a human skin explants ex vivo model (Part 1. Experimental 70% hydrofluoric acid (HF) burns: Histological observations in an established human skin explants ex vivo model) described the lesions that appeared following 70% HF penetration. Within 5min, 70% HF penetrates to the dermis. Using the same experimental conditions, a comparison study of two different washing protocols was performed: water + topical calcium gluconate (CaG) versus Hexafluorine®. In these conditions, washing for 15min with running tap water followed by topical CaG ointment only delayed burn onset, while severe tissue damage appeared later. In contrast, after washing with Hexafluorine® over 10 min, no histological lesions developed. These results are in accordance with the results of accidental human industrial case reports. Conclusion/significance: Amphoteric and hypertonic Hexafluorine® can deactivate H+ and chelate F- ions. Based on these results, it should be considered as a promising first-aid decontamination solution to prevent or minimize significant local and systemic consequences of concentrated HF skin exposures.

Burgher, Francois; Mathieu, Laurence; Lati, Elian; Gasser, Philippe; Peno-Mazzarino, Laurent; Blomet, Joel; Hall, Alan H; Maibach, Howard I

2011-01-01

31

Carbonation of municipal solid waste incineration electrostatic precipitator fly ashes in solution.  

PubMed

Carbonation was applied to a Pb- and Zn-contaminated fraction of municipal solid waste incineration electrofilter fly ashes in order to reduce heavy metal leaching. Carbonation tests were performed in solution, by Na2CO3 addition or CO2 bubbling, and were compared with washing (with water only). The injection of CO2 during the washing did not modify the mineralogy, but the addition of Na2CO3 induced the reaction with anhydrite, forming calcite. Microprobe analyses showed that Pb and Zn contamination was rather diffuse and that the various treatments had no effect on Pb and Zn speciation in the residues. The leaching tests indicated that carbonation using Na2CO3 was successful because it gave a residue that could be considered as non-hazardous material. With CO2 bubbling, Pb and Zn leaching was strongly decreased compared with material washed with water alone, but the amount of chromium extracted became higher than the non-hazardous waste limits for landfilling. PMID:24718362

De Boom, Aurore; Aubert, Jean-Emmanuel; Degrez, Marc

2014-05-01

32

Selective adsorption of phenanthrene dissolved in surfactant solution using activated carbon.  

PubMed

Selective adsorption of a hazardous hydrophobic organic compound (HOC) by activated carbon as a means of recovering surfactants after a soil washing process was investigated. As a model system, phenanthrene was selected as a representative HOC and Triton X-100 as a nonionic surfactant. Three activated carbons that differed in size (Darco 20-40 (D20), 12-20 (D12) and 4-12 (D4) mesh sizes) were used in adsorption experiments. Adsorption of surfactant onto activated carbon showed a constant maximum above the critical micelle concentration, which were 0.30, 0.23, 0.15 g g(-1) for D20, D12, and D4, respectively. Selectivity for phenanthrene to Triton X-100 was much higher than 1 over a wide range of activated carbon doses (0-6 g l(-1)) and initial phenanthrene concentrations (10-110 mg l(-1)). Selectivity generally increased with decreasing particle size, increasing activated carbon dose, and decreasing initial concentration of phenanthrene. The highest selectivity was 74.9, 57.3, and 38.3 for D20, D12, and D4, respectively, at the initial conditions of 10 mg l(-1) phenanthrene, 5 g l(-1) Triton X-100 and 1g l(-1) activated carbon. In the case of D20 at the same conditions, 86.5% of the initial phenanthrene was removed by sorption and 93.6% of the initial Triton X-100 remained in the solution following the selective adsorption process. The results suggest that the selective adsorption by activated carbon is a good alternative for surfactant recovery in a soil washing process. PMID:17658582

Ahn, Chi K; Kim, Young M; Woo, Seung H; Park, Jong M

2007-11-01

33

Adsorption of Paraquat dichloride from aqueous solution by activated carbon derived from used tires.  

PubMed

The removal of pesticide from wastewater under different batch experimental conditions, using a car tire derived activated carbon was investigated. The pesticide utilized in the study was Paraquat dichloride (1,1-dimethyl-4,4-bipyridyl dichloride), which is a well known herbicide. The adsorbent was produced from the pyrolysis and activation of used tires (TAC). The performances of this adsorbent and a commercial activated carbon F300 (CAC) have been compared. It was determined that the adsorption of Paraquat was weakly pH dependent. The effects of particle size, carbon dosage, temperature and the initial concentration of the Paraquat were studied. Further experiments investigating the regeneration capabilities of the tire-supplied carbon were performed. The regenerated carbons that were washed with basic pH solution were found to have the best sorption capacity recovery. It was found that the rate of sorption of Paraquat onto the carbon is very fast with almost 90% of the maximum possible adsorption taking place in the first 5 min. Nevertheless, the batch sorption kinetics was fitted for a first-order reversible reaction, a pseudo-first-order reaction and a pseudo-second-order reaction. The pseudo-second-order chemical reaction model appears to provide the best correlation. The applicability of the Langmuir isotherm for the present system has been evaluated at different temperatures. The isotherms show that the sorption capacity of CAC decreases with temperature and the dominant mechanism of CAC adsorption is physical sorption. PMID:15225939

Hamadi, Nadhem K; Sri Swaminathan; Chen, Xiao Dong

2004-08-01

34

Stability of calcium carbonate and magnesium carbonate in rainwater and nitric acid solutions  

Microsoft Academic Search

Carbonation of magnesium and calcium silicates has emerged as an interesting option for long term storage of captured CO2. However, carbonated minerals are not stable in acidic environments. This study was conducted to determine if synthetically carbonated minerals dissolve in acidic rain and release CO2. Synthetic magnesium and calcium carbonates were leached in nitric acid solutions of various acidities, as

Sebastian Teir; Sanni Eloneva; Carl-Johan Fogelholm; Ron Zevenhoven

2006-01-01

35

Wash This Way  

NSDL National Science Digital Library

In this activity on page 4 of the PDF, learners investigate the importance of washing their hands. Learners "dirty" their hands with cooking spray and glitter and then clean their hands using various hand-washing techniques. Learners compare the hand-washing techniques and discuss how germs can be harmful. Safety notes: Safety goggles are required. Follow all of Milli's safety tips on the bottom of the page.

Society, American C.

2011-01-01

36

Wash water recovery system  

NASA Technical Reports Server (NTRS)

The Wash Water Recovery System (WWRS) is intended for use in processing shower bath water onboard a spacecraft. The WWRS utilizes flash evaporation, vapor compression, and pyrolytic reaction to process the wash water to allow recovery of potable water. Wash water flashing and foaming characteristics, are evaluated physical properties, of concentrated wash water are determined, and a long term feasibility study on the system is performed. In addition, a computer analysis of the system and a detail design of a 10 lb/hr vortex-type water vapor compressor were completed. The computer analysis also sized remaining system components on the basis of the new vortex compressor design.

Deckman, G.; Rousseau, J. (editor)

1973-01-01

37

Viability and functional integrity of washed platelets  

SciTech Connect

The viability and functional integrity of saline- and ACD-saline-washed platelets were compared with those of unwashed platelets. After template bleeding time (TBT) was measured, 15 healthy volunteers underwent plateletpheresis and ingested 600 mg of aspirin. Autologous /sup 111/In-labeled platelets were transfused: unwashed (n = 5), washed with 0.9 percent saline solution (SS) (n = 5), and washed with a buffered 12.6 percent solution of ACD-A in 0.9 percent saline solution (n = 5). After transfusion, we measured TBT at 1, 4, and 24 hours; platelet survival at 10 minutes and 1, 4, and 24 hours and daily for 6 days; and the percentage of uptake in liver and spleen by quantitative whole-body radionuclide scintigraphy at 24 and 190 hours. We found that saline washing affected platelet recovery, 23.47 +/- 12 percent (p less than 0.001) as compared to 52.43 +/- 17 percent (p less than 0.002) for ACD-saline and 73.17 +/- 8 percent for control; that saline washing resulted in a greater liver uptake than control and ACD-saline-washed platelets (31.9 +/- 8% (p less than 0.001) vs 17.7 +/- 4.1 and 19.3 +/- 2.1% (p greater than 0.1), respectively); that, unlike control and ACD-saline-washed platelets, saline-washed platelets did not shorten bleeding time; and that neither type of washing affected survival. Although ACD-saline washing affects recovery, it also results in intact function, normal survival, higher recovery than SS platelets, and no significant liver uptake.

Pineda, A.A.; Zylstra, V.W.; Clare, D.E.; Dewanjee, M.K.; Forstrom, L.A.

1989-07-01

38

Simulation of the flow of aqueous solutions through carbon nanotubes  

NASA Astrophysics Data System (ADS)

The flow of aqueous NaCl and NaI solutions through carbon nanotubes is treated by extensive molecular dynamics simulations. The dependence of diverse transport features on the solute specificity, the nanotube geometry, and the various atomic models employed, including polarizability, is addressed in detail. The interpretations are developed in conjunction with the structural details of the solution and the energy barriers the solute components have to overcome.

Beu, Titus A.

2011-09-01

39

Solution Deposition Methods for Carbon Nanotube Field-Effect Transistors.  

National Technical Information Service (NTIS)

This study evaluated different methods for controlled deposition of carbon nanotubes (CNTs) from solution onto a silicon substrate to make CNT field-effect transistors (FETs). The goal of this deposition was to achieve reproducible device properties throu...

M. Ervin N. Salaets

2009-01-01

40

EPA'S MOBILE VOLUME REDUCTION UNIT FOR SOIL WASHING  

EPA Science Inventory

This paper discusses the design and initial operation of the U.S. Environmental Protection Agency'S (EPA) Mobile Volume Reduction Unit (VRU) for soil washing. oil washing removes contaminants from soils by dissolving or suspending them in the wash solutions (which can be later tr...

41

BIOGENESIS SOIL WASHING TECHNOLOGY - INNOVATIVE TECHNOLOGY EVALUATION REPORT  

EPA Science Inventory

Soil washing technologies are designed to transfer contaminants from soil to a liquid phase. he BioGenesis Soil Washing Technology uses soil washing with a proprietary surfactant solution to transfer organic contaminants from soils to wastewater. ontaminant levels are further red...

42

Adsorption of chromium by activated carbon from aqueous solution  

Microsoft Academic Search

Adsorption isotherms of Cr(III) and Cr(VI) ions on two samples of activated carbon fibres and two samples of granulated activated carbons from aqueous solutions in the concentration range 20–1000 mg\\/l have been studied. The adsorption isotherms have been determined after modifying the activated carbon surfaces by oxidation with nitric acid, ammonium persulphate, hydrogen peroxide and oxygen gas at 350°C and

Diksha Aggarwal; Meenakshi Goyal; R. C. Bansal

1999-01-01

43

Soil washing enhancement with solid sorbents  

SciTech Connect

Soil washing is a dynamic, physical process that remediates contaminated soil through two mechanisms: particle size separation and transfer of the contaminant into the (mostly) liquid stream. The performance of different sorbents and additives to remove motor oil from sea sand was tested. Hydrocyclone, attrition scrubber, and froth flotation equipment were used for the decontamination study. Sorbents and additives were mixed with soils in the attrition scrubber prior to flotation. Sorbents used were granular activated carbon, powder activated carbon, and rubber tires. Chemical additives used were calcium hydroxide, sodium carbonate, Alconox{reg_sign}, Triton{reg_sign} X-100 and Triton{reg_sign} X-114. When a froth flotation run was performed using no additive, washed soils {open_quotes}tails{close_quotes} contained 4000 ppm of total oil and grease (TOG). However, when carbon or rubber (6% by weight) was added to the contaminated soils the washed soils {open_quotes}tails{close_quotes} contained 4000 ppm of total oil and grease (TOG). The addition of sodium carbonate or calcium hydroxide (6% by weight) had same effects as sorbents. In both cases washed soil {open_quotes}tails{close_quotes} contained total oil and grease of less than 1000 ppm. The use of these non-hazardous additives or sorbent can enhance the soil washing process and consequently saves on time (residence time in equipment design) required to achieve the target clean up levels. 18 refs., 12 figs.

El-Shoubary, Y.M. [Merck & Co., Somerset, NJ (United States); Woodmansee, D.E. [GE Corporate Research & Development, Schenectady, NY (United States)

1996-12-31

44

Inhibition Of Washed Sludge With Sodium Nitrite  

SciTech Connect

This report describes the results of electrochemical tests used to determine the relationship between the concentration of the aggressive anions in washed sludge and the minimum effective inhibitor concentration. Sodium nitrate was added as the inhibitor because of its compatibility with the DWPF process. A minimum of 0.05M nitrite is required to inhibit the washed sludge simulant solution used in this study. When the worst case compositions and safety margins are considered, it is expected that a minimum operating limit of nearly 0.1M nitrite will be specified. The validity of this limit is dependent on the accuracy of the concentrations and solubility splits previously reported. Sodium nitrite additions to obtain 0.1M nitrite concentrations in washed sludge will necessitate the additional washing of washed precipitate in order to decrease its sodium nitrite inhibitor requirements sufficiently to remain below the sodium limits in the feed to the DWPF. Nitrite will be the controlling anion in "fresh" washed sludge unless the soluble chloride concentration is about ten times higher than predicted by the solubility splits. Inhibition of "aged" washed sludge will not be a problem unless significant chloride dissolution occurs during storage. It will be very important tomonitor the composition of washed sludge during processing and storage.

Congdon, J. W.; Lozier, J. S.

2012-09-25

45

Quantum conductance steps in solutions of multiwalled carbon nanotubes.  

PubMed

We have prepared solutions of multiwalled carbon nanotubes in Aroclor 1254, a mixture of polychlorinated biphenyls. The solutions are stable at room temperature. Transport measurements were performed using a scanning-tunneling probe on a sample prepared by spin coating the solution on gold substrates. Conductance steps were clearly seen. A histogram of a high number of traces shows maximum peaks at integer values of the conductance quantum G(0)=2e(2)/h, demonstrating ballistic transport at room temperature along the carbon nanotube over distances longer than 1.4 microm. PMID:12689021

Urbina, A; Echeverría, I; Pérez-Garrido, A; Díaz-Sánchez, A; Abellán, J

2003-03-14

46

Corrosion behavior of titanium-clad carbon steel in weakly alkaline solutions  

Microsoft Academic Search

The electrochemical polarization curves and corrosion potentials during long-term immersion of Ti, carbon steel, carbon steel tightened-Ti and Ti-clad carbon steel specimens were investigated in bentonite-contacting solution (mixture of sodium sulfate and sodium carbonate solutions), sodium sulfate solution and borate solution adjusted to pH=9.0–9.84. Ti and carbon steel were passivated during immersion in borate solution, while carbon steel was corroded

Kazuhisa Azumi; Masahiro Seo

2003-01-01

47

Anomalous distribution in atom map of solute carbon in steel.  

PubMed

The distribution of carbon in atom probe tomography maps was investigated in various phases of steel. Carbon atoms in 3D atom maps of martensite and cementite phases showed an almost uniform distribution. On the other hand, carbon atoms in ferrite were consistently enriched along the zone line joining the (0 0 2) and the (2 2 2) poles, and in the depth direction of analysis, which was different from the actual distribution. The width and concentration of the enriched regions remained unchanged at a specimen temperature ranging from 90 to 30K. Moreover, the ratio of molecular carbon ions to total carbon ions decreased with decreasing temperature, but did not change between the enriched and diluted regions. Based on the results, the reason for the anomalous distribution of solute carbon atoms in atom maps is discussed. PMID:21292398

Kobayashi, Y; Takahashi, J; Kawakami, K

2011-05-01

48

Proper hand washing (image)  

MedlinePLUS

... handwashing include: Take off any jewelry Hold your hands pointing down under warm water for 15 to ... Steps for proper hand washing include: Take off any jewelry. Hold your hands pointing down under warm water for 15 to 30 seconds. ...

49

Electroreduction of carbon dioxide in aqueous solutions at metal electrodes  

SciTech Connect

The quantities of carbon stored in the form of atmospheric carbon dioxide, CO{sub 2} in the hydrosphere and carbonates in the terrestrial environment substantially exceed those of fossil fuels. In spite of this the industrial use of carbon dioxide as a source of chemical carbon is presently limited to preparation of urea and certain carboxylic acids as well as organic carbonates and polycarbonates. However, the situation is expected to change in the future, if effective catalytic systems allowing to activate carbon dioxide will become available. In this connection, the electrochemical reduction of CO{sub 2}, requiring only an additional input of water and electrical energy, appears as an attractive possibility. For more than 100 years formic acid and formates of alkali metals were considered as the only significant products of the electroreduction of carbon dioxide in aqueous solutions. The highest current efficiencies, exceeding 90 %, were obtained either with mercury or with amalgam electrodes. The only comprehensive study regarding kinetics of CO{sub 2} reduction in aqueous solution has been performed by Eyring et al. using a mercury cathode. This paper describes electrolysis studies.

Augustynski, J.; Jermann, B.; Kedzierzawski, P. [Univ. of Geneva (Switzerland)

1996-12-31

50

Effect of solutes on austenite processing in ultralow carbon steels  

NASA Astrophysics Data System (ADS)

The effects of solutes in austenite in ultra-low carbon steel has to date not been sufficiently investigated. In order to gain an understanding of this, a series of steels were designed which feature the effects of particular elements in solution in austenite: boron, niobium, molybdenum, sulfur, phosphorus, and carbon. The influence of these solutes on austenite recrystallization kinetics, austenite flow stress, austenite to ferrite transformation, hot band texture development, and grain size evolution were studied. It was found that the elements in solution retarded the austenite recrystallization kinetics, with the largest influence coming from the boron addition. The solutes also tended to increase the activation energy for recrystallization, and raised the recrystallization stop temperature. Austenite flow stress was increased by the solutes, especially at lower temperatures. The solute elements had little effect on the transformation temperatures, but some elements such as boron, niobium, and molybdenum, caused the formation of non-polygonal ferrite when deformed material was quenched from austenite, leading to a microstructure with higher hardness. It was also found that in these steels the austenite grain size of hot band reached a stable value when re-heated in austenite, with the stable grain size varying for the different solutes. The influences of the solutes were related to the action of atoms which are segregated to the grain boundaries in austenite.

Mutschler, Ralph Andrew, Jr.

51

Ultrafast Carbon-Carbon SingleBond Rotational Isomerization in Room-Temperature Solution  

Microsoft Academic Search

Generally, rotational isomerization about the carbon-carbon single bond in simple ethane derivatives in room-temperature solution under thermal equilibrium conditions has been too fast to measure. We achieved this goal using two-dimensional infrared vibrational echo spectroscopy to observe isomerization between the gauche and trans conformations of an ethane derivative, 1-fluoro-2-isocyanato-ethane (1), in a CCl4 solution at room temperature. The isomerization time

Junrong Zheng; Kyungwon Kwak; Jia Xie; M. D. Fayer

2006-01-01

52

Precipitation of calcium and magnesium carbonates from homogeneous supersaturated solutions  

Microsoft Academic Search

Homogeneous (unseeded) precipitation of calcium and magnesium carbonates in the CaO–MgO–CO2–H2O system in supersaturated solutions was investigated. The induction period (?) of spontaneous nucleation and the composition of precipitated solid phases were determined. The influence of saturation degree (chemical affinity) and Mg2+\\/Ca2+ activity ratio in solution on the kinetics of CaCO3 nucleation was studied. The order of CaCO3 homogeneous nucleation

O. S. Pokrovsky

1998-01-01

53

Electrosorption of Ions from Aqueous Solutions by Nanostructured Carbon Aerogel  

Microsoft Academic Search

Electrosorption is generally defined as potential-induced adsorption on the surface of charged electrodes. After polarization of the electrodes, ions are removed from the electrolyte solution by the imposed electric field and adsorbed onto the surface of the electrodes. Experimental and modeling studies were conducted using two types of carbon aerogel composites of different surface areas to provide a better understanding

Tung-Yu Ying; Kun-Lin Yang; Sotira Yiacoumi; Costas Tsouris

2002-01-01

54

Domestic wash water reclamation  

NASA Technical Reports Server (NTRS)

System consists of filtration unit, reverse-osmosis module, tanks, pumps, plumbing, and various gauges, meters, and valves. After water is used in washing machine or shower, it is collected in holding tank. Water is pumped through series of five particulate filters. Pressure tank supplies processed water to commode water closet.

Hall, J. B., Jr.; Batten, C. E.; Wilkins, J. R.

1974-01-01

55

Soil washing treatability study  

SciTech Connect

Soil washing was identified as a viable treatment process option for remediating soil at the FEMP Environmental Management Project (FEMP). Little information relative to the specific application and potential effectiveness of the soil washing process exists that applies to the types of soil at the FEMP. To properly evaluate this process option in conjunction with the ongoing FEMP Remedial Investigation/Feasibility Study (RI/FS), a treatability testing program was necessary to provide a foundation for a detailed technical evaluation of the viability of the process. In August 1991, efforts were initiated to develop a work plan and experimental design for investigating the effectiveness of soil washing on FEMP soil. In August 1992, the final Treatability Study Work Plan for Operable Unit 5: Soil Washing (DOE 1992) was issued. This document shall be referenced throughout the remainder of this report as the Treatability Study Work Plan (TSWP). The purpose of this treatability study was to generate data to support initial screening and the detailed analysis of alternatives for the Operable Unit 5 FS.

Krstich, M.

1995-12-01

56

Efficacy of 1.5% Dish Washing Solution and 95% Lemon Water in Substituting Perilous Xylene as a Deparaffinizing Agent for Routine H and E Staining Procedure: A Short Study  

PubMed Central

Aim. To assess the efficacy of dish washing solution and diluted lemon water in deparaffinizing sections during conventional hematoxylin and eosin staining technique. Objective. The objective is to utilize eco-friendly economical substitute for xylene. Materials and Methods. Using twenty paraffin embedded tissue blocks, three sections each were prepared. One section was stained with conventional H and E method (Group A) and the other two sections with xylene-free (XF) H and E (Groups B and C). Staining characteristics were compared with xylene and scoring was given. Total score of 3–5 was regarded as adequate for diagnosis and less than that inadequate for diagnosis. Statistical Analysis. Chi-square test, Kruskal Wallis ANOVA test, and Mann-Whitney U test were used. Results. Adequacy of nuclear staining, crispness, and staining for diagnosis were greater in both Groups A and C (100%) than Group B (95%). Adequacy of cytoplasmic staining was similar in all the three groups (100%). Group B showed comparatively superior uniform staining and less retention of wax. Conclusion. Dish washing solution or diluted lemon water can be replaced for xylene as deparaffinizing agent in hematoxylin and eosin procedure.

Ananthaneni, Anuradha; Namala, Srilekha; Guduru, Vijay Srinivas; Ramprasad, V. V. S.; Ramisetty, Sabitha Devi; Udayashankar, Urmila; Naik, Kiran Kumar

2014-01-01

57

Simultaneous leaching and carbon sequestration in constrained aqueous solutions.  

PubMed

The behavior of metal ions' leaching and precipitated mineral phases of metal-rich fly ash (FA) was examined in order to evaluate microbial impacts on carbon sequestration and metal immobilization. The leaching solutions consisted of aerobic deionized water (DW) and artificial eutrophic water (AEW) that was anaerobic, organic- and mineral-rich, and higher salinity as is typical of bottom water in eutrophic algae ponds. The Fe- and Ca-rich FAs were predominantly composed of quartz, mullite, portlandite, calcite, hannebachite, maghemite, and hematite. After 86 days, only Fe and Ca contents exhibited a decrease in leaching solutions while other major and trace elements showed increasing or steady trends in preference to the type of FA and leaching solution. Ca-rich FA showed strong carbon sequestration efficiency ranging up to 32.3 g CO(2)/kg FA after 86 days, corresponding to almost 65% of biotic carbon sequestration potential under some conditions. Variations in the properties of FAs such as chemical compositions, mineral constituents as well as the type of leaching solution impacted CO(2) capture. Even though the relative amount of calcite increased sixfold in the AEW and the relative amount of mineral phase reached 37.3 wt% using Ca-rich FA for 86 days, chemical sequestration did not accomplish simultaneous precipitation and sequestration of several heavy metals. PMID:21246259

Moon, Ji-Won; Cho, Kyu-Seong; Moberly, James G; Roh, Yul; Phelps, Tommy J

2011-12-01

58

Lead removal via soil washing and leaching  

NASA Astrophysics Data System (ADS)

A soil washing and leaching process was tested for removing lead from soils. A soil-washing circuit, including size and gravity separations, was employed to remove the coarse metallic lead particles, while the leaching was applied to remove fine metallic lead particles and other lead species. The soil-washing tests proved that the metallic lead particles larger than 0.15 mm (100 mesh) could be effectively removed. The sodium-chloride-based leaching solution with ferric chloride or sodium hypochlorite as oxidants was adopted in the leaching. The leaching experimental results indicated that under the pH of 2 and Eh of 1,300 mV, the metallic lead particles smaller than 0.15 mm and other lead species can be dissolved in the leaching solution within 60 minutes.

Lin, H. K.; Man, X. D.; Walsh, D. E.

2001-12-01

59

Hydrogen and carbon in solid solution in oxides and silicates  

Microsoft Academic Search

The dissolution of H2O and CO2 in structurally dense, nominally anhydrous and non-carbonate oxide matrices such as MgO and CaO is reviewed. H2O and CO2 are treated as gaseous oxide components which enter into solid solution with the refractory oxide hosts. They form anion complexes associated with cation vacancy sites. Evidence is presented that OH- pairs which derive from the

Friedemann Freund

1987-01-01

60

Simultaneous leaching and carbon sequestration in constrained aqueous solutions  

Microsoft Academic Search

The behavior of metal ions’ leaching and precipitated mineral phases of metal-rich fly ash (FA) was examined in order to evaluate\\u000a microbial impacts on carbon sequestration and metal immobilization. The leaching solutions consisted of aerobic deionized\\u000a water (DW) and artificial eutrophic water (AEW) that was anaerobic, organic- and mineral-rich, and higher salinity as is typical\\u000a of bottom water in eutrophic

Ji-Won Moon; Kyu-Seong Cho; James G. Moberly; Yul Roh; Tommy J. Phelps

2011-01-01

61

Washing Out the Competition  

NASA Technical Reports Server (NTRS)

AJT Associates, Inc. (AJT) worked with NASA to develop a revolutionary ozone-based laundry system. AJT's TecH2Ozone(R) wash system presents its customers with an energy-efficient, cost-effective, and environmentally safe way to perform commercial laundering. TecH2Ozone significantly reduces the amount of water and chemical used as compared to traditional commercial laundry systems. This reduction has resulted in lower cost and shorter wash cycles. And due to the reduced use of chemicals, a significant portion of the rinse water is recycled back into the system for reuse. TecH2Ozone customers, such as hotels and other large commercial laundry facilities, have felt the benefits of this equipment. Because of the reduced cycle times, fewer washers are needed and there is a notable increase in the cleanliness of the laundry. The reduction in chemical residues is a boon to customers with allergies and those prone to skin irritation from chemicals retained in regular laundry. AJT Associates, Inc. (AJT) worked with NASA to develop a revolutionary ozone-based laundry system. AJT's TecH2Ozone(R) wash system presents its customers with an energy-efficient, cost-effective, and environmentally safe way to perform commercial laundering.

2001-01-01

62

Aqueous chemical wash compositions  

SciTech Connect

This patent describes an aqueous, substantially unfoamed chemical wash composition having properties making it suitable for use as a pre-flush in well cementing operations and/or for removal of drilling mud from a borehole at a temperature of from about 150/sup 0/F to about 270/sup 0/F, the wash a. being predominantly composed of water, b. containing an active surfactant component comprising a combination of (1) from about 0.1 to about 1.5 weight percent (total weight basis) of a water soluble anionic surfactant; (2) from about 0.1 to about 1.5 weight percent (total weight basis) of a nonionic surfactant; and (3) from about 0.05 to about 0.54 weight percent (total weight basis) of at least one water soluble amphoteric surfactant, and c. having dispersed therein a heterogeneous mixture of distinct particles comprising both a first particulate oil soluble resin which is friable and a second particulate oil soluble resin which is pliable and where the size of the friable resin particles ranges from about 0.5 to about 300 microns and the size of the pliable resin particles ranges from about 0.05 to about 30 microns. The amount of the friable-pliable resin mixture is sufficient to impart effective fluid loss control to the chemical wash composition.

Bannister, C.E.

1987-07-21

63

Insights into non-Fickian solute transport in carbonates  

PubMed Central

[1] We study and explain the origin of early breakthrough and long tailing plume behavior by simulating solute transport through 3-D X-ray images of six different carbonate rock samples, representing geological media with a high degree of pore-scale complexity. A Stokes solver is employed to compute the flow field, and the particles are then transported along streamlines to represent advection, while the random walk method is used to model diffusion. We compute the propagators (concentration versus displacement) for a range of Peclet numbers (Pe) and relate it to the velocity distribution obtained directly on the images. There is a very wide distribution of velocity that quantifies the impact of pore structure on transport. In samples with a relatively narrow spread of velocities, transport is characterized by a small immobile concentration peak, representing essentially stagnant portions of the pore space, and a dominant secondary peak of mobile solute moving at approximately the average flow speed. On the other hand, in carbonates with a wider velocity distribution, there is a significant immobile peak concentration and an elongated tail of moving fluid. An increase in Pe, decreasing the relative impact of diffusion, leads to the faster formation of secondary mobile peak(s). This behavior indicates highly anomalous transport. The implications for modeling field-scale transport are discussed. Citation: Bijeljic, B., P. Mostaghimi, and M. J. Blunt (2013), Insights into non-Fickian solute transport in carbonates, Water Resour. Res., 49, 2714–2728, doi:10.1002/wrcr.20238.

Bijeljic, Branko; Mostaghimi, Peyman; Blunt, Martin J

2013-01-01

64

Lysimeter washing of MSW incinerator bottom ash  

Microsoft Academic Search

Stockpiled municipal waste incinerator bottom ash is frequently considered for utilization as a construction material. Two 360 kg lysimeter experiments were conducted to study percolation washing of contaminants from stockpiled MSW bottom ash. One lysimeter was leached with a concentrated sodium hydroxide solution, as a possible pre-treatment for improvement of the bottom ash characteristics prior to utilization, while the other

J. A. Stegemann; J. Schneider; B. W. Baetz; K. L. Murphy

1995-01-01

65

Fluidic delivery of homogeneous solutions through carbon tube bundles.  

PubMed

A wide array of technological applications requires localized high-rate delivery of dissolved compounds (in particular, biological ones), which can be achieved by forcing the solutions or suspensions of such compounds through nano or microtubes and their bundled assemblies. Using a water-soluble compound, the fluorescent dye Rhodamine 610 chloride, frequently used as a model drug release compound, it is shown that deposit buildup on the inner walls of the delivery channels and its adverse consequences pose a severe challenge to implementing pressure-driven long-term fluidic delivery through nano and microcapillaries, even in the case of such homogeneous solutions. Pressure-driven delivery (3-6 bar) of homogeneous dye solutions through macroscopically-long (approximately 1 cm) carbon nano and microtubes with inner diameters in the range 100 nm-1 microm and their bundled parallel assemblies is studied experimentally and theoretically. It is shown that the flow delivery gradually shifts from fast convection-dominated (unobstructed) to slow jammed convection, and ultimately to diffusion-limited transport through a porous deposit. The jamming/clogging phenomena appear to be rather generic: they were observed in a wide concentration range for two fluorescent dyes in carbon nano and microtubes, as well as in comparable transparent glass microcapillaries. The aim of the present work is to study the physics of jamming, rather than the chemical reasons for the affinity of dye molecules to the tube walls. PMID:19531856

Srikar, R; Yarin, A L; Megaridis, C M

2009-07-01

66

Comparison of alternative washing systems for heliostats  

Microsoft Academic Search

Two methods are proposed for washing heliostat mirrors in a solar central receiver facility. One method involves truck mounted washing mechanisms continuously traversing the heliostat field, washing mirrors sequentially on a fixed schedule. The other concept involves a washing unit affixed to each heliostat, permitting near simultaneous washing of all heliostats on demand. The former, scheduled washing system has the

A. Kerstein

1981-01-01

67

Insights into non-Fickian solute transport in carbonates  

NASA Astrophysics Data System (ADS)

We study and explain the origin of early breakthrough and long tailing plume behavior by simulating solute transport through 3-D X-ray images of six different carbonate rock samples, representing geological media with a high degree of pore-scale complexity. A Stokes solver is employed to compute the flow field, and the particles are then transported along streamlines to represent advection, while the random walk method is used to model diffusion. We compute the propagators (concentration versus displacement) for a range of Peclet numbers (Pe) and relate it to the velocity distribution obtained directly on the images. There is a very wide distribution of velocity that quantifies the impact of pore structure on transport. In samples with a relatively narrow spread of velocities, transport is characterized by a small immobile concentration peak, representing essentially stagnant portions of the pore space, and a dominant secondary peak of mobile solute moving at approximately the average flow speed. On the other hand, in carbonates with a wider velocity distribution, there is a significant immobile peak concentration and an elongated tail of moving fluid. An increase in Pe, decreasing the relative impact of diffusion, leads to the faster formation of secondary mobile peak(s). This behavior indicates highly anomalous transport. The implications for modeling field-scale transport are discussed.

Bijeljic, Branko; Mostaghimi, Peyman; Blunt, Martin J.

2013-05-01

68

Washing treatment of automotive shredder residue (ASR).  

PubMed

Worldwide, the amount of end-of-life vehicles (ELVs) reaches 50 million units per year. Once the ELV has been processed, it may then be shredded and sorted to recover valuable metals that are recycled in iron and steelmaking processes. The residual fraction, called automotive shredder residue (ASR), represents 25% of the ELV and is usually landfilled. In order to deal with the leachable fraction of ASR that poses a potential threat to the environment, a washing treatment before landfilling was applied. To assess the potential for full-scale application of washing treatment, tests were carried out in different conditions (L/S = 3 and 5L/kgTS; t = 3 and 6 h). Moreover, to understand whether the grain size of waste could affect the washing efficiency, the treatment was applied to ground (<4 mm) and not-ground samples. The findings obtained revealed that, on average, washing treatment achieved removal rates of more than 60% for dissolved organic carbon (DOC), chemical oxygen demand (COD) and total Kjeldahl nitrogen (TKN). With regard to metals and chlorides, sulphates and fluoride leachable fraction, a removal efficiency of approximately 60% was obtained, as confirmed also by EC values. The comparison between the results for ground and not-ground samples did not highlight significant differences. PMID:23706987

Cossu, Raffaello; Lai, Tiziana

2013-08-01

69

Laboratory testing in-tank sludge washing, summary letter report  

SciTech Connect

In-tank washing is being considered as a means of pretreating high-level radioactive waste sludges, such as neutralized current acid waste (NCAW) sludge. For this process, the contents of the tank will be allowed to settle, and the supernatant solution will be decanted and removed. A dilute sodium hydroxide/sodium nitrite wash solution will be added to the settled sludge and the tank contents will be mixed with a mixer pump system to facilitate washing of the sludge. After thorough mixing, the mixer pumps will be shut off and the solids will be allowed to re-settle. After settling, the supernatant solution will be withdrawn from the tank, and the wash cycle will be repeated several times with fresh wash solution. Core sample data of double shell tank 241-AZ-101 indicate that settling of NCAW solids may be very slow. A complicating factor is that strong thermal currents are expected to be generated from heat produced by radionuclides in the sludge layer at the bottom of the tank. Additionally, there are concerns that during the settling period (i.e., while mixing pumps and air-lift re-circulators are shut off), the radionuclides may heat the residual interstitial water in the sludge to the extent that violent steam discharges (steam bumping) could occur. Finally, there are concerns that during the washing steps sludge settling may be hindered as a result of the reduced ionic strength of the wash solution. To overcome the postulated reduced settling rates during the second and third washing steps, the use of flocculants is being considered. To address the above concerns and uncertainties associated with in-tank washing, PNL has conducted laboratory testing with simulant tank waste to investigate settling rates, steam bump potential, and the need for and use of flocculating agents.

Norton, M.V.; Torres-Ayala, F.

1994-09-01

70

Adsorption of nickel(II) from aqueous solution onto activated carbon prepared from coirpith  

Microsoft Academic Search

Activated carbon has been prepared from coirpith by chemical activation and characterized. Carbonised coirpith is able to adsorb Ni(II) from aqueous solution. It was noted that a decreasing in the carbon concentration with constant Ni concentration, or an increase in the Ni concentration with constant carbon concentration resulted in a higher nickel uptake per unit weight of carbon. The Langmuir

K. Kadirvelu; K. Thamaraiselvi; C. Namasivayam

2001-01-01

71

Activated Carbon Open Circuit Potential Shifts in Aqueous Solutions  

Microsoft Academic Search

Interaction of certain organic compounds with activated carbon and its effect on the carbon open circuit potentials were studied. It was shown that shifts in open circuit potentials depended on the filling of the activated carbon surface. Whereas adsorption of the investigated compounds on the carbon led to positive potential shifts, their elimination (desorption) from carbon surface led to shifts

Mikhail M. Goldin; Gary Blanchard; Alexander Volkov; Mogely Khubutiya; Vladimir Kolesnikov; Anatoly Evseev; Mark Goldin

2007-01-01

72

Ethylbenzene Removal by Carbon Nanotubes from Aqueous Solution  

PubMed Central

The removal of ethylbenzene (E) from aqueous solution by multiwalled, single-walled, and hybrid carbon nanotubes (MWCNTs, SWCNTs, and HCNTs) was evaluated for a nanomaterial dose of 1?g/L, concentration of 10–100?mg/L, and pH 7. The equilibrium amount removed by SWCNTs (E: 9.98?mg/g) was higher than by MWCNTs and HCNTs. Ethylbenzene has a higher adsorption tendency on CNTs, so that more than 98% of it adsorbed in first 14?min, which is related to the low water solubility and the high molecular weight. The SWCNTs performed better for ethylbenzene sorption than the HCNTs and MWCNTs. Isotherms study indicates that the BET isotherm expression provides the best fit for ethylbenzene sorption by SWCNTs. Carbon nanotubes, specially SWCNTs, are efficient and rapid adsorbents for ethylbenzene which possess good potential applications to maintain high-quality water. Therefore, it could be used for cleaning up environmental pollution to prevent ethylbenzene borne diseases.

Bina, Bijan; Pourzamani, Hamidreza; Rashidi, Alimorad; Amin, Mohammad Mehdi

2012-01-01

73

Uranium (VI) sorption by multiwalled carbon nanotubes from aqueous solution  

NASA Astrophysics Data System (ADS)

Sorption of uranium (VI) from aqueous solutions onto Multiwalled Carbon Nanotubes (MWCNTs) has been studied under varying experimental conditions of initial uranium concentration, contact time, pH, and temperature, to assess the kinetic and equilibrium parameters. The optimum pH for sorption of uranium (VI) onto MWCNTs was 5. The kinetic data were fitted with pseudo-first-order, pseudo-second-order, and intra-particle diffusion models. The sorption process was well described by pseudo-second-order kinetics. The uranium sorption data were fitted by the Langmuir, Freundlich, and Dubinin-Radushkevich equilibrium models to obtain the characteristic parameters of each model. The Langmuir isotherm was found to best represent the measured sorption data. According to the evaluation using the Langmuir model, the maximum sorption capacity of uranium (VI) ions onto MWCNTs increased with temperature, from 24.9 to 39.1 mg g-1 when the temperature was increased from 298 to 318 K. The calculated sorption thermodynamic parameters including ?G°, ?H°, and ?S° indicated the spontaneous nature of uranium sorption onto MWCNTs. The results suggest that MWCNTs are suitable materials for preconcentration and solidification of uranium (VI) species from aqueous solutions.

Fasfous, Ismail I.; Dawoud, Jamal N.

2012-10-01

74

Experimental fractionation of stable carbon isotopes during degassing of carbon dioxide and precipitation of calcite from aqueous solutions  

NASA Astrophysics Data System (ADS)

Processes in the carbonate system of surface waters are in particular sensitive to variations of boundary conditions as, for instance, the partial pressure of carbon dioxide in the atmosphere and the aqueous solution. Examples range from streams, rivers, to coastal marine waters. The flux of carbon dioxide from continental flowing waters was recently included into calculations of the global carbon budget (Butman & Raymond, 2011, Nature Geo.). These solutions, are often supersaturated in carbon dioxide with respect to the atmosphere. The degassing of carbon dioxide is associated with a kinetically controlled fractionation of the stable carbon isotopes, which has to be considered in balancing water-air carbon dioxide fluxes. The degassing process additionally leads to the super-saturation of the aqueous solution with respect to calcium carbonate. Stable isotope fractionation is of particular value to identify and quantify processes at the water-gas phase interface and link these non-equilibrium processes to the formation mechanisms of calcite and the hydrodynamics of surface waters. Experiments were carried out with or without inert N2 gas flow to degas carbon dioxide from initially supersaturated solutions. Natural solutions used are from different stations of the Elbe estuary, the Jade Bay, the backbarrier tidal area of Spiekeroog Island, carbonate springs of Rügen Island, and the Baltic Sea coastline. Results are compared experiments using bottled mineral waters. By following the (physico) chemical changes in the solutions (pH, TA, Ca PHREEQC modeling) it was found, that two evolutionary stages can be differentiated. Reaction progress led to the preferential liberation of carbon dioxide containing the light carbon isotope, following a Rayleigh-type process. After an induction period, where only degassing of carbon dioxide took place, a second stage was observed where calcite began to form from the highly supersaturated solutions. In this stage the carbonate system of the solution was controlled by both, degassing and carbonate precipitation, still leading to an enrichment of the heavier carbon isotope in the residual DIC. The experimental results are evaluated for both periods, and the influence of salinity and pH is extracted. Acknowledgement: Parts of this study were supported by BMBF within the BIOACID project

Müller, K.; Winde, V.; Escher, P.; von Geldern, R.; Böttcher, M. E.

2012-04-01

75

Effect of washing treatments on pesticide residues and antioxidant compounds in Yuja ( Citrus junos Sieb ex Tanaka)  

Microsoft Academic Search

This study investigated the removal efficiency of pesticide residues and microorganisms, and changes of the amount of antioxidant\\u000a compounds on yuja (Citrus junos Sieb ex Tanaka) by various washing methods. The washing methods were mechanical washing (MW), mechanical washing after soaking\\u000a in SAcEW, strong acidic electrolyzed water (SAcEW+MW), and soaking detergent solution (DW), with a tap water washing (TW)\\u000a as

Jung-Min Sung; Ki-Hyun Kwon; Jong-Hoon Kim; Jin-Woong Jeong

2011-01-01

76

Results Of Routine Strip Effluent Hold Tank, Decontaminated Salt Solution Hold Tank, Caustic Wash Tank And Caustic Storage Tank Samples From Modular Caustic-Side Solvent Extraction Unit During Macrobatch 6 Operations  

SciTech Connect

Strip Effluent Hold Tank (SEHT), Decontaminated Salt Solution Hold Tank (DSSHT), Caustic Wash Tank (CWT) and Caustic Storage Tank (CST) samples from several of the ''microbatches'' of Integrated Salt Disposition Project (ISDP) Salt Batch (''Macrobatch'') 6 have been analyzed for {sup 238}Pu, {sup 90}Sr, {sup 137}Cs, and by Inductively Coupled Plasma Emission Spectroscopy (ICPES). The results from the current microbatch samples are similar to those from comparable samples in Macrobatch 5. From a bulk chemical point of view, the ICPES results do not vary considerably between this and the previous macrobatch. The titanium results in the DSSHT samples continue to indicate the presence of Ti, when the feed material does not have detectable levels. This most likely indicates that leaching of Ti from MST in ARP continues to occur. Both the CST and CWT samples indicate that the target Free OH value of 0.03 has been surpassed. While at this time there is no indication that this has caused an operational problem, the CST should be adjusted into specification. The {sup 137}Cs results from the SRNL as well as F/H lab data indicate a potential decline in cesium decontamination factor. Further samples will be carefully monitored to investigate this.

Peters, T. B.

2013-10-01

77

Nasal Wash Treatment  

MedlinePLUS

... or Tap water that is filtered using a filter with an absolute pore size of 1 micron or smaller. Whichever water you use to make the saline solution replace container or water at least weekly. To make the ...

78

Stable aqueous colloidal solutions of intact surfactant-free graphene nanoribbons and related graphitic nanostructures.  

PubMed

Here we demonstrate a simple, nondestructive method for the preparation of stable aqueous colloidal solutions of graphene nanoribbons and carbon nanotubes. The method includes sonication of carbon nanomaterials in hypophosphorous acid, filtration accompanied by washing the solids with water and dispersion of the solids in a fresh portion of water to form colloidal solutions. PMID:23435853

Dimiev, Ayrat M; Gizzatov, Ayrat; Wilson, Lon J; Tour, James M

2013-04-01

79

Prototype wash water renovation system integration with goverment-furnished wash fixture  

NASA Technical Reports Server (NTRS)

A total renovation concept for removing objectionable materials from spacecraft wash water to make the water reusable was developed. This concept included ferric chloride pretreatment to coagulate suspended solids such as soap and lint, pressure filtration, and carbon adsorption and ion exchange to remove trace dissolved organics and inorganic salts. A breadboard model which was developed to demonstrate the design adequacy of the various system components and the limits on system capacities and efficiencies.

1983-01-01

80

Comparison of Alternative Washing Systems for Heliostats.  

National Technical Information Service (NTIS)

Two methods have been proposed for washing heliostat mirrors in a solar central receiver facility. One method involves truck-mounted washing mechanisms continuously traversing the heliostat field, washing mirrors sequentially on a fixed schedule. The othe...

A. Kerstein

1981-01-01

81

A model for the adsorption of single metal ion solutes in aqueous solution onto activated carbon produced from pecan shells  

Microsoft Academic Search

Adsorption isotherms for activated carbon made from pecan shells have been obtained at 25°C and an approximate pH of 3 for a number of metal ion solutes. It was found that the Slips and Freundlich equations were satisfactory for explaining the experimental data. The correlation of metal ion adsorption with the solute parameters of metal ion electronegativity and first stability

Seyed A. Dastgheib; David A. Rockstraw

2002-01-01

82

Reducing Corrosion of Stainless Steel in Hot Nitric Acid Solutions by Adding Carbon Black or Elemental Sulfur to the Solution.  

National Technical Information Service (NTIS)

The corrosive effect toward stainless steel of a boiling nitric acid solution containing dissolved chromium values in the plus six oxidation state is reduced. Carbon black is added to the solution to reduce the corrosion. The stainless steel vessels are u...

F. G. Rust

1965-01-01

83

Physical solubility of hydrogen sulfide and carbon dioxide in alkanolamine solutions  

Microsoft Academic Search

The study was undertaken to develop a method that would make direct measurements of acid gases, hydrogen sulfide and carbon dioxide, physical solubilities in aqueous alkanolamine solutions possible. Hydrogen sulfide and carbon dioxide physical solubilities in 20, 35, and 50% by weight diethanolamine aqueous solutions were measured. The solubility measurements were made at acid gas partial pressure up to 1000

Abu-Arabi

1988-01-01

84

Pecan shell activated carbon: synthesis, characterization, and application for the removal of copper from aqueous solution  

Microsoft Academic Search

Activated carbon with a high adsorption capacity for removal of copper ions from aqueous solution is produced from pecan shells. Air and phosphoric acid are used for the oxidation and the modification or development of oxygen- or phosphorus\\/oxygen-containing groups on the carbon surface. It was found that the adsorption capacity of the produced carbon is significantly higher than that of

Seyed A Dastgheib; David A Rockstraw

2001-01-01

85

Preparation of regenerated cellulose fiber via carbonation. I. Carbonation and dissolution in an aqueous NaOH solution  

Microsoft Academic Search

Cellulose carbonate was prepared by the reaction of cellulose pulp and CO2 with treatment reagents, such as aqueous ZnCl2 (20–40 wt%) solution, acetone or ethyl acetate, at ?5–0°C and 30–40 bar (CO2) for 2 hr. Among the treatment reagents, ethyl acetate was the most effective. Cellulose carbonate was dissolved in 10% sodium\\u000a hydroxide solution containing zinc oxide up to 3

Sang Youn Oh; Dong Il Yoo; Younsook Shin; Wha Seop Lee; Seong Mu Jo

2002-01-01

86

Solubility of carbon dioxide in aqueous solutions of 2-amino-2-methyl-1,3-propanediol  

Microsoft Academic Search

The equilibrium solubility of carbon dioxide in aqueous solutions of 2-amino-2-methyl-1,3-propanediol (AMPD) has been measured at (30, 40, and 60) C and the partial pressure of carbon dioxide ranging from (0.5 to 3065) kPa. The concentrations of the aqueous solutions were (10 and 30) mass % AMPD. The tendency of the solubility of carbon dioxide in 30 mass % AMPD

Jeom-In Baek; Ji-Ho Yoon

1998-01-01

87

Solubility of carbon dioxide in aqueous solutions of 2-amino-2-methyl-1,3-propanediol  

SciTech Connect

The equilibrium solubility of carbon dioxide in aqueous solutions of 2-amino-2-methyl-1,3-propanediol (AMPD) has been measured at (30, 40, and 60) C and the partial pressure of carbon dioxide ranging from (0.5 to 3065) kPa. The concentrations of the aqueous solutions were (10 and 30) mass % AMPD. The tendency of the solubility of carbon dioxide in 30 mass % AMPD aqueous solution at 40 C was found to be similar to that in 30 mass % N-methyldiethanolamine aqueous solution.

Baek, J.I.; Yoon, J.H. [Korea Electric Power Research Inst., Taejon (Korea, Republic of). Center for advanced Studies in Energy and the Environment] [Korea Electric Power Research Inst., Taejon (Korea, Republic of). Center for advanced Studies in Energy and the Environment

1998-07-01

88

Relation Between the Adsorbed Quantity and the Immersion Enthalpy in Catechol Aqueous Solutions on Activated Carbons  

PubMed Central

An activated carbon, CarbochemTM—PS230, was modified by chemical and thermal treatment in flow of H2, in order to evaluate the influence of the activated carbon chemical characteristics in the adsorption of the catechol. The catechol adsorption in aqueous solution was studied along with the effect of the pH solution in the adsorption process of modified activated carbons and the variation of immersion enthalpy of activated carbons in the aqueous solutions of catechol. The interaction solid-solution is characterized by adsorption isotherms analysis, at 298 K and pH 7, 9 and 11 in order to evaluate the adsorption value above and below that of the catechol pKa. The adsorption capacity of carbons increases when the solution pH decreases. The retained amount increases slightly in the reduced carbon to maximum adsorption pH and diminishes in the oxidized carbon. Similar conclusions are obtained from the immersion enthalpies, whose values increase with the solute quantity retained. In granular activated carbon (CAG), the immersion enthalpies obtained are between 21.5 and 45.7 J·g?1 for catechol aqueous solutions in a range of 20 at 1500 mg·L?1.

Moreno-Pirajan, Juan Carlos; Blanco, Diego; Giraldo, Liliana

2012-01-01

89

On the black carbon problem and its solutions  

NASA Astrophysics Data System (ADS)

Black carbon (BC) warms air temperatures in at least seven major ways: (a) directly absorbing downward solar radiation, (b) absorbing upward reflected solar radiation when it is situated above bright surfaces, such as snow, sea ice, and clouds, (c) absorbing some infrared radiation, (d) absorbing additional solar and infrared radiation upon obtaining a coating, (e) absorbing radiation multiply reflected within clouds when situated interstitially between cloud drops, (f) absorbing additional radiation when serving as CCN or scavenged inclusions within cloud drops, and (g) absorbing solar radiation when deposited on snow and sea ice, reducing the albedos of both. Modeling of the climate effects of BC requires treatment of all these processes in detail. In particular, treatment of BC absorption interstitially between cloud drops and from multiply-dispersed cloud drop BC inclusions must be treated simultaneously with treatment of cloud indirect effects to determine the net effects of BC on cloud properties. Here, results from several simulations of the effects of BC from fossil fuel and biofuel sources on global and regional climate and air pollution health are summarized. The simulations account for all the processes mentioned. Results are found to be statistically significant relative to chaotic variability in the climate system. Over time and in steady state, fossil-fuel soot plus biofuel soot are found to enhance warming more than methane. The sum of the soots causes less steady-state warming but more short term warming than does carbon dioxide. Thus eliminating soot emissions from both sources may be the fastest method of reducing rapid climate warming and possibly the only method of saving the Arctic ice. Eliminating such emissions may also reduce over 1.5 million deaths worldwide, particularly in developing countries. Short term mitigation options include the targeting of fossil-fuel and biofuel BC sources with particle traps, new stove technologies, and rural electrification. However, the real solution, to be implemented over a 20-40 year period is complete conversion of the combustion infrastructure to electricity and electrolytic hydrogen, where the electricity is all produced by near-zero emitting wind, water, and solar (WWS) based energy technologies. Such a conversion would reduce BC and greenhouse gases simultaneously with cooling aerosol particles. This would ramp down the presence of both warming and cooling agents, but still cause net reduction of global warming, while reducing devastating health impacts that are occurring from both warming and cooling aerosols.

Jacobson, M. Z.

2010-12-01

90

Coated carbon hemoperfusion provides limited clearance of protein-bound solutes.  

PubMed

This study assessed the capacity of a cartridge containing coated granular carbon to clear protein-bound solutes. Clearances for test solutes were measured while an albumin solution representing plasma was pumped from a 10 L reservoir through the cartridge at a rate of 200 mL/min for 5 h. Clearance values for phenol red, phenytoin, and indican were well below the limit imposed by the plasma flow and declined with time. The clearance of phenol red, which was the most tightly bound solute, fell from 38 +/- 12 to 17 +/- 2 mL/min. Additional studies revealed that the cartridge contained enough carbon to absorb all the protein-bound test solutes, but that the rate of their clearance was limited by the inability of granular carbon to take up solutes rapidly at a low concentration. The rate of solute uptake at low concentration was shown to be much greater when carbon was in powdered rather than granular form. A device in which approximately 50 g of powdered carbon was recirculated in the dialysate compartment of hollow fiber kidneys cleared phenol red and phenytoin more rapidly than the hemoperfusion cartridge containing 300 g of coated granular carbon. These results indicate that hemoperfusion over coated granular carbon provides limited clearance of protein-bound solutes. PMID:18684207

Dinh, Diana C; Recht, Natalie S; Hostetter, Thomas H; Meyer, Timothy W

2008-09-01

91

Extracting lithium from waste solutions of chemico-metallurgical lithium carbonate production  

Microsoft Academic Search

In order to reduce the loss of lithium in waste solutions of chemico-metallurgical lithium carbonate production, it is suggested\\u000a to extract lithium from these solutions in the form of poorly soluble hydroxodialuminate under the action of sodium and potassium\\u000a aluminates. Technological tests showed that the proposed method ensures almost complete isolation of lithium from waste solutions\\u000a of lithium carbonate production.

V. I. Samoilov; N. A. Kulenova

2008-01-01

92

Inhibition Performance of Enhanced-Mo Inhibitor for Carbon Steel in 55% LiBr Solution  

Microsoft Academic Search

The inhibition performance of enhanced-Mo inhibitor for carbon steel in 55% LiBr solution was measured by means of chemical immersion, electrochemical measurements, and physical detection technologies. Results indicated that enhanced-Mo inhibitor showed excellent inhibition performance of carbon steel in 55% LiBr solution, especially at high temperature. With increasing the temperature of solution from 160 °C to 240 °C, the corrosion

Cheng-hao LIANG; Xian-qi HU

2008-01-01

93

Destruction of carbon disulfide in aqueous solutions by sonochemical oxidation.  

PubMed

Carbon disulfide (CS(2)) is toxic to animals and aquatic organisms, and can also decompose to carbonyl sulfide (OCS) and hydrogen sulfide (H(2)S) in aqueous environment. The kinetics of the sonochemical degradation of aqueous CS(2) was studied in a batch reactor at 20kHz and 20 degrees C, and the effects of process parameters (e.g. concentration, ultrasonic intensity, irradiating gas) investigated. The concentrations of unbuffered CS(2) solutions used were (6.4-7.0) x 10(-4), 10.5 x 10(-4) and (13.2-13.6) x 10(-4)M and the intensities were varied from 14 to 50W. The reaction rate was found to be zero-order and the rate constant for the degradation at 20 degrees C and 14W in air was 21.1 microM/min using the largest initial concentration range studied. At the same initial concentration range but at 50W (39.47W/m(2)) the degradation rate of CS(2) was 46.7 microM/min, more than two times that at 14W (11.04W/m(2)). The rate of CS(2) sonochemical degradation in the presence of the different gases was in the order of He>air> or =N(2)O>Ar; the rate with helium was found to be about three times that of argon. The formation of sulfate (SO(4)(2-)) as reaction product with air as the irradiating gas was enhanced in the presence of hydrogen peroxide (H(2)O(2)) and inhibited in the presence of 1-butanol. The sonochemical oxidation of CS(2) may prove to be an efficient and environmentally benign way for the removal of this hazardous pollutant from natural water and wastewater. PMID:11893423

Appaw, Collins; Adewuyi, Yusuf G

2002-03-29

94

Enhanced sludge washing evaluation plan  

SciTech Connect

The Tank Waste Remediation System (TWRS) Program mission is to store, treat, and immobilize highly radioactive Hanford Site waste (current and future tank waste and the strontium/cesium capsules) in an environmentally sound, safe, and cost-effective manner. The scope of the TWRS Waste Pretreatment Program is to treat tank waste and separate that waste into HLW and LLW fractions and provide additional treatment as required to feed LLW and HLW immobilization facilities. Enhanced sludge washing was chosen as the baseline process for separating Hanford tank waste sludge. Section 1.0 briefly discusses the purpose of the evaluation plan and provides the background that led to the choice of enhanced sludge washing as the baseline process. Section 2.0 provides a brief summary of the evaluation plan details. Section 3.0 discusses, in some detail, the technical work planned to support the evaluation of enhanced sludge washing. Section 4.0 briefly discusses the potential important of policy issues to the evaluation. Section 5.0 discusses the methodology to be used in the evaluation process. Section 6.0 summarizes the milestones that have been defined to complete the enhanced sludge washing evaluation and provides a summary schedule to evaluate the performance of enhanced sludge washing. References are identified in Section 7.0, and additional schedule and milestone information is provided in the appendices.

Jensen, R.D.

1994-09-01

95

Fabrication and processing of high-strength densely packed carbon nanotube yarns without solution processes.  

PubMed

Defects of carbon nanotubes, weak tube-tube interactions, and weak carbon nanotube joints are bottlenecks for obtaining high-strength carbon nanotube yarns. Some solution processes are usually required to overcome these drawbacks. Here we fabricate ultra-long and densely packed pure carbon nanotube yarns by a two-rotator twisting setup with the aid of some tensioning rods. The densely packed structure enhances the tube-tube interactions, thus making high tensile strengths of carbon nanotube yarns up to 1.6 GPa. We further use a sweeping laser to thermally treat as-produced yarns for recovering defects of carbon nanotubes and possibly welding carbon nanotube joints, which improves their Young's modulus by up to ?70%. The spinning and laser sweeping processes are solution-free and capable of being assembled together to produce high-strength yarns continuously as desired. PMID:22538869

Liu, Kai; Zhu, Feng; Liu, Liang; Sun, Yinghui; Fan, Shoushan; Jiang, Kaili

2012-06-01

96

Carbonate-modified siloxanes as solvents of electrolyte solutions for rechargeable lithium cells  

Microsoft Academic Search

Influence of mixing carbonate-modified siloxanes into LiPF6-ethylene carbonate (EC)\\/ethylmethyl carbonate (EMC) (mixing volume ratio=3:7) mixed solvent electrolytes on charge–discharge cycling properties of lithium was examined. As the solute, 1M (M: molL?1) LiPF6 was used. As siloxanes, 4-(2-trimethylsilyloxydimethylsilylethyl)-1,3-dioxolan-2-one and 4-(2-bis(trimethylsilyloxy)methylsilylethyl)-1,3-dioxolan-2-one were investigated. These siloxanes are derivatives of butylene cyclic carbonate or vinyl ethylene carbonate. Charge–discharge cycling efficiencies of lithium metal anodes

Takashi Takeuchi; Satoshi Noguchi; Hideyuki Morimoto; Shin-ichi Tobishima

2010-01-01

97

Extraction of palladium from acidic solutions with the use of carbon adsorbents  

SciTech Connect

We studied the sorption of palladium(II) on LKAU-4, LKAU-7, and BAU carbon adsorbents from model hydrochloric acid solutions and the solutions of spent palladium-containing catalysts. It was found that sorbents based on charcoal (BAU) and anthracite (LKAU-4) were characterized by high sorption capacities for palladium. The kinetics of the saturation of carbon adsorbents with palladium(II) ions was studied, and it was found that more than 60% of the initial amount of Pd(II) was recovered in a 1-h contact of an adsorbent with a model solution. This value for the solutions of spent catalysts was higher than 35%.

O.N. Kononova; N.G. Goryaeva; N.B. Dostovalova; S.V. Kachin; A.G. Kholmogorov [Krasnoyarsk State University, Krasnoyarsk (Russian Federation)

2007-08-15

98

Thermodynamic properties of carbon in b.c.c. and f.c.c. iron-silicon-carbon solid solutions.  

NASA Technical Reports Server (NTRS)

The equilibrium between hydrogen-methane gas mixtures and Fe-Si-C solid solutions has been investigated both as a function of temperature and carburizing gas composition. The thermodynamic properties of the carbon atoms in both b.c.c. and f.c.c. solid solution have been derived from the equilibrium measurements. The results found have been compared with those of earlier investigations and with the predictions of recent theoretical models on ternary solid solutions containing both substitutional and interstitial solute atoms.

Chraska, P.; Mclellan, R. B.

1971-01-01

99

Solution-processed carbon electrodes for organic field-effect transistors  

NASA Astrophysics Data System (ADS)

Bottom-contact organic transistors with carbon-paste electrodes are fabricated by means of the surface selective deposition technique, where a carbon-paste solution is deposited on the region in which the self-assembled monolayers are removed by ultraviolet light irradiation. The resulting bottom-contact pentacene transistor realizes high performance of 1.0 cm2 V-1 s-1. The present method is applied to solution-processed polythiophene transistors as well as n-channel materials.

Wada, Hiroshi; Mori, Takehiko

2008-11-01

100

Reactions of rare earth flourides with sodium carbonate and hydroxide solutions  

Microsoft Academic Search

Exchange interactions of sparingly soluble rare earth (RE) compounds such as fluorides, carbonates, and hydroxides in aqueous media are studied. The starting materials were fluorides of individual RE, obtained by precipitation with hydrofluoric acid from solutions of RE nitrates, which were prepared from the corresponding oxides of 99.9% and taken to the air-dry state, and also cp sodium carbonate and

E. L. Chuviliana; N. V. Baryshnikov; I. F. Poletaev

1986-01-01

101

Removal of reactive dye from aqueous solutions by adsorption onto activated carbons prepared from oak sawdust  

Microsoft Academic Search

Activated carbons prepared from oak sawdust, a timber industry waste, have been examined for the removal of remazol brilliant blue (RB) dye from aqueous solutions through batch adsorption technique. Activated carbons were prepared from oak sawdust by chemical activation with 10% HNO3 (AC1) followed by pyrolysis at 500°C in the absence of air and by physical activation at 500°C in

Mona Mahmoud Abd El-Latifa; Amal Mozarei Ibrahim

2010-01-01

102

Removal of cyanide from aqueous solutions by plain and metal-impregnated granular activated carbons  

Microsoft Academic Search

In this study, the removal of free cyanide from aqueous solutions by activated carbon was investigated. Effects of metal impregnation (Cu and Ag), aeration, and concentrations of adsorbent and cyanide on the rate and extent of the removal of cyanide were studied. The results have shown that the capacity of activated carbon for the removal of cyanide can be significantly

H. Deveci; E. Y. Yaz?c?; I. Alp; T. Uslu

2006-01-01

103

Visible-light photoconversion of carbon dioxide into organic acids in an aqueous solution of carbon dots.  

PubMed

Carbon "quantum" dots (or carbon dots) have emerged as a new class of optical nanomaterials. Beyond the widely reported bright fluorescence emissions in carbon dots, their excellent photoinduced redox properties that resemble those found in conventional semiconductor nanostructures are equally valuable, with photon-electron conversion applications from photovoltaics to CO2 photocatalytic reduction. In this work we used gold-doped carbon dots from controlled synthesis as water-soluble catalysts for a closer examination of the visible-light photoconversion of CO2 into small organic acids, including acetic acid (for which the reduction requires many more electrons than that for formic acid) and, more interestingly, for the significantly enhanced photoconversion with higher CO2 pressures over an aqueous solution of the photocatalysts. The results demonstrate the nanoscale semiconductor-equivalent nature of carbon dots, with excellent potential in energy conversion applications. PMID:24972094

Sahu, Sushant; Liu, Yamin; Wang, Ping; Bunker, Christopher E; Fernando, K A Shiral; Lewis, William K; Guliants, Elena A; Yang, Fan; Wang, Jinping; Sun, Ya-Ping

2014-07-22

104

A basket for washing benthological samples  

USGS Publications Warehouse

Since benthological samples collected with dredges are usually too large to be preserved in toto, a washing method must be employed to reduce the sample volume without losing or damaging the organisms. Traditionally, the sample is washed in a sieve until the volume is small enough for convenient handling or preservation. Most washing procedures are time-consuming and laborious. To save time in washing samples, a washing 'basket' was designed which accomadates a Ponar dredge. The only additional equipment needed to employ the washing basket effectively is a pump that delivers about 8 gallons of water per minute.

Selgeby, James H.

1971-01-01

105

Comparison of alternative washing systems for heliostats  

SciTech Connect

Two methods have been proposed for washing heliostat mirrors in a solar central receiver facility. One method involves truck-mounted washing mechanisms continuously traversing the heliostat field, washing mirrors sequentially on a fixed schedule. The other concept involves a washing unit affixed to each heliostat, permitting near-simultaneous washing of all heliostats on demand. The former, scheduled washing system has the advantage of lower capital costs, while the latter, responsive system has more operational flexibility. Cost-benefit evaluation of the two systems, taking into account the random nature of rainfall patterns and soiling processes, indicates that the scheduled system is preferable.

Kerstein, A.

1981-04-01

106

Remediation of cadmium-contaminated paddy soils by washing with calcium chloride: verification of on-site washing.  

PubMed

We developed a new, three-step soil-wash method to remediate Cd-contaminated paddy fields. The method comprises (1) chemically washing the field soil with a CaCl2 solution; (2) washing the treated soil with water to eliminate residual Cd and CaCl2; and (3) on-site treatment of wastewater using a portable wastewater treatment system. Cd concentrations in the treated water were below Japan's environmental quality standard (0.01 mg Cd L-1), and the removal of Cd from the exchangeable fraction was 55% and from the acid-soluble fraction 15%. While soil fertility properties were affected by the soil washing, adverse effects were not crucial and could be corrected. The washing had no affect on rice growth, and reduced the average Cd concentration in rice grains by about two-thirds compared to a control plot. These results confirmed the effectiveness of the soil-wash method in remediating Cd-contaminated paddy fields. PMID:17141928

Makino, Tomoyuki; Kamiya, Takashi; Takano, Hiroyuki; Itou, Tadashi; Sekiya, Naoki; Sasaki, Kouta; Maejima, Yuji; Sugahara, Kazuo

2007-05-01

107

Wash flow disturbance and summer wash flow in the Mojave Desert: Influence on dispersion, production, and physiological functioning of dominant shrubs  

NASA Astrophysics Data System (ADS)

In many Mojave Desert ecosystems, water infiltrates to root-zones in greatest proportion via washes. As such, washes have a pronounced effect on plant dispersion and size across these landscapes. Desert roads alter the natural spatial patterns of washes on alluvial fans (locally called bajadas) and potentially affect plant production and distribution. As a winter-rainfall dominated ecosystem, climate changes in the Mojave Desert that increase summer precipitation may also play an important role in altering vegetation processes influenced by washes. Road effects on the spatial distribution of desert plants on a Mojave Desert bajada were examined using remotely sensed LiDAR data and ground based measurements of plant size. Plant physiological responses to summer wash flow were also quantified by measuring gas exchange and water status of two dominant perennial species, Larrea tridentata and Ambrosia dumosa. Larrea and Ambrosia plants were nearly 7x and 4x larger where wash flow has been enhanced by road culverts, relative to undisturbed areas and areas where flow has been cut-off by the presence of a road/railroad. Clustering of large plants occurred along wash margins, with clustering most pronounced in areas of enhanced wash flow. No clustering was found where wash flow has been eliminated. For ecophysiological traits, both species showed pronounced responses to the pulse of water; however, these responses varied as a function of distance from wash. Larrea plants within 3 m and Ambrosia plants within ca. 2 m from the wash responded to the pulse of water. Leaf phenology dictated the timing of carbon gain as Larrea experienced a rapid but short-lived increase in stomatal conductance compared to a significant response for over a month following the pulse for Ambrosia. These results indicate that disturbance of desert washes has a pronounced impact on vegetation structure, and changing climatic conditions that impact plant function could potentially lead to even greater vegetation shifts through time.

Newlander, April

108

Inhibitive effects of palm kernel oil on carbon steel corrosion by alkaline solution  

NASA Astrophysics Data System (ADS)

The behavior of carbon steel SAE 1045 in 1 M NaOH solution containing different concentrations of palm kernel oil (PKO) has been studied by weight loss and polarization measurement. Results showed that the corrosion of carbon steel in NaOH solution was considerably reduced in presence of such inhibitors. The inhibition efficiency increases when concentration of inhibitor increase. Maximum inhibition efficiency (? 96.67%) is obtained at PKO concentration 8 v/v %. This result revealed that palm kernel oil can act as a corrosion inhibitor in an alkaline medium. Corrosion rates of carbon steel decrease as the concentration of inhibitor is increased.

Zulkafli, M. Y.; Othman, N. K.; Lazim, A. M.; Jalar, A.

2013-11-01

109

Na(+)-functionalized carbon quantum dots: a new draw solute in forward osmosis for seawater desalination.  

PubMed

A new type of biocompatible draw solute, Na(+)-functionalized carbon quantum dots (Na_CQDs) with ultra-small size and rich ionic species, in forward osmosis (FO) is developed for seawater desalination. The aqueous dispersion of Na_CQDs demonstrates a high osmotic pressure, which allows high FO water flux and negligible reverse solute permeation. PMID:24870226

Guo, Chun Xian; Zhao, Dieling; Zhao, Qipeng; Wang, Peng; Lu, Xianmao

2014-06-12

110

Effect of niobium on massive transformation in ultra low carbon steels: a solute drag treatment  

Microsoft Academic Search

The effect of Nb on the ? ? ? transformation in ultra low carbon steels is examined experimentally and theoretically. It is shown that there are two modes of the massive transformation. One of them is heavily influenced by the solute drag effect of Nb. This is confirmed by a calculation based on a new model for treating the solute

M. Suehiro; Z.-K. Liu; J. Ågren

1996-01-01

111

Hydrogen Permeation of Carbon Steel in Weak Alkaline Solution Containing Hydrogen Sulfide and Cyanide Ion  

Microsoft Academic Search

The hydrogen permeation behavior of carbon steel (CS) was investigated electrochemically in weak alkaline solutions containing hydrogen sulfide (HâS) with various cyanide ion (CN⁻) concentrations under open-circuit conditions. Anodic and cathodic polarization behaviors of CS also were investigated under the same environmental conditions. Little hydrogen content (Câ) was detected in alkaline solutions without CN⁻. However, when a small amount of

K. Yamakawa; R. Nishimura

1999-01-01

112

Solution-deposited carbon nanotube layers for flexible display applications  

Microsoft Academic Search

We have investigated two possible fields of application for carbon nanotube (CNT) networks in flexible displays. Transparent and conductive layers of CNTs were spray coated onto glass and plastic substrates. The spectral transmission of the produced layers is almost even for all wavelengths in the visible regime. A sheet resistance of 400?\\/? at a transmittance of 80% was achieved.Thin-film transistors

Axel Schindler; Jochen Brill; Norbert Fruehauf; James P. Novak; Zvi Yaniv

2007-01-01

113

Ecological Engineering promotes Carbon Reduction Solutions for a Sustainable Planet  

Microsoft Academic Search

Due to un-prescedented; social, industrial and human reproductive growth, our global society is rapidly approaching peak development, coupling with climate change factors and accelerating Earths current 'melt cycle'. Our challenge is to do more with less; to question the 'way' it has always been done; to develop innovative low carbon engineering tools; to design and mimic natural eco-systems and to

Stephen Bedford Clark

2009-01-01

114

Mechanism of adsorption and electrosorption of bentazone on activated carbon cloth in aqueous solutions.  

PubMed

An electrochemical technique has been applied to enhance the removal of a common herbicide (bentazone) from aqueous solutions using an activated carbon cloth as electrode. A pH increase from acidic to basic reduces the uptake, with capacities going from 127 down to 80 mg/g at pH 2 and 7, respectively. Increasing the oxygen content of the carbon cloth causes a decrease in the bentazone loading capacity at all pH values. This indicates that adsorption is governed by both dispersive and electrostatic interactions, the extent of which is controlled by the solution pH and the nature of the adsorbent. Anodic polarization of the carbon cloth noticeably enhances the adsorption of bentazone, to an extent depending on the current applied to the carbon electrode. The electrosorption is promoted by a local pH decrease provoked by anodic decomposition of water in the pores of the carbon cloth. PMID:17490705

Ania, Conchi O; Béguin, François

2007-08-01

115

Inhibition Effect of Dodecylamine on Carbon Steel Corrosion in Hydrochloric Acid Solution  

NASA Astrophysics Data System (ADS)

Dodecylamine spontaneously adsorbs on carbon steel via its polar group (-NH2) in hydrochloric acid solution. Furthermore, it forms a monolayer film on carbon steel surface. The inhibition mechanism of dodecylamine for carbon steel is geometric blocking effect. The adsorption of dodecylamine on carbon steel surface follows Arrhenius equation. The adsorption slightly increases activated energy, but greatly reduces pre-exponential factor value. Atomic force microscopy force curves indicate that at the area without adsorbed dodecylamine, no obvious adhere force occurs. At the area with adsorbed dodecylamine, however, an average 1.3 nN adhere force is observed.

Chen, Zhenyu; Huang, Ling; Qiu, Yubing; Guo, Xingpeng

2012-12-01

116

Evaluation of solution-processable carbon-based electrodes for all-carbon solar cells.  

PubMed

Carbon allotropes possess unique and interesting physical, chemical, and electronic properties that make them attractive for next-generation electronic devices and solar cells. In this report, we describe our efforts into the fabrication of the first reported all-carbon solar cell in which all components (the anode, active layer, and cathode) are carbon based. First, we evaluate the active layer, on standard electrodes, which is composed of a bilayer of polymer sorted semiconducting single-walled carbon nanotubes and C(60). This carbon-based active layer with a standard indium tin oxide anode and metallic cathode has a maximum power conversion efficiency of 0.46% under AM1.5 Sun illumination. Next, we describe our efforts in replacing the electrodes with carbon-based electrodes, to demonstrate the first all-carbon solar cell, and discuss the remaining challenges associated with this process. PMID:23113673

Ramuz, Marc P; Vosgueritchian, Michael; Wei, Peng; Wang, Chenggong; Gao, Yongli; Wu, Yingpeng; Chen, Yongsheng; Bao, Zhenan

2012-11-27

117

Nonionic organic solute sorption onto two organobentonites as a function of organic-carbon content  

Microsoft Academic Search

Sorption of three nonionic organic solutes (benzene, trichloroethene, and 1,2-dichlorobenzene) to hexadecyltrimethylammonium bentonite (HDTMA bentonite) and benzyltriethylammonium bentonite (BTEA bentonite) was measured as a function of total organic-carbon content at quaternary ammonium cation loadings ranging from 30 to 100% of the clay's cation-exchange capacity. Sorption of all three solutes to HDTMA bentonite was linear and sorption of all three solutes

Shannon L. Bartelt-Hunt; Susan E. Burns; James A. Smith

2003-01-01

118

Investigation of texturization for crystalline silicon solar cells with sodium carbonate solutions  

Microsoft Academic Search

We investigate a new texturization technique for crystalline silicon solar cells with sodium carbonate (Na2CO3) solutions. We show the dependence of the hemispherical surface reflectance on solution temperature, the etching time and the Na2CO3 concentration. Furthermore, we investigate what element in Na2CO3 solution influences the texturing for reducing the texturing time. As a result of experiments, we find it possible

Y Nishimoto; K Namba

2000-01-01

119

21 CFR 1250.87 - Wash water.  

Code of Federal Regulations, 2011 CFR

...2014-04-01 2014-04-01 false Wash water. 1250.87 Section 1250.87 Food and...Conditions on Vessels § 1250.87 Wash water. Where systems installed on vessels for wash water, as defined in § 1250.3(n), do...

2014-04-01

120

Binder for Carbon-Fiber Coating  

NASA Technical Reports Server (NTRS)

Insoluble, even coating formed by soaking in polyacrylic acid. Carbon fiber material prepared by soaking in solution of 20 percent polyacrylic acid in water. Material blotted and dried at 120 degrees C for at least 2 hours. Dried material reacted with boiling aqueous solution of calcium acetate. Treated material removed from boiling solution, blotted, dried at 120 degrees C, washed with distilled water, and dried again.

Dowler, W. L.; Ramohalli, K. N.; Yen, S. P. S.; Mueller, W. A.; Harper, J.

1984-01-01

121

Relations for the determination of the polymorphic composition of calcium carbonate precipitated in saturated sodium chloride solutions  

Microsoft Academic Search

The purification of concentrated sodium chloride solutions from calcium and magnesium ions is realized by precipitating them in the form of calcium carbonate and magnesium hydroxide using a reagent solution composed of sodium carbonate and sodium hydroxide. The functioning of the industrial process depends on the polymorphic composition of the precipitated calcium carbonate. The classical experimental design method is used

C. Berger; A. Dandeu; C. Carteret; B. Humbert; H. Muhr; E. Plasari; J. M. Bossoutrot

122

Wash resistance of insecticide-treated materials.  

PubMed

The effectiveness of insecticide-treated materials (ITMs) for malaria control is reduced by washing them. This research in Colombia and Bolivia investigated the resistance of different insecticide formulations and, in particular, a commercially available impregnated bednet (PermaNet) which provides chemical protection for the insecticide. The fabrics studied were all polyester; the pyrethroids used for impregnation were deltamethrin (tablet and suspension concentrate both at 25 mg/m2 target dose), lambdacyhalothrin (capsule suspension at 15 mg/m2; laboratory study only), alphacypermethrin (suspension concentrate at 40 mg/m2) and, in the case of PermaNet, deltamethrin (55 mg/m2). The indicator of wash resistance was Anopheles spp. mortality (using the bioassay cone method) before and after different numbers and intensities of washing. When the fabrics were washed under controlled conditions, gently with water and a bar of soap, the wash resistance of all formulations was good (100% Anopheles mortality after 3 washes). However, when the impregnated nets were soaked for 30-60 min and washed with soap powder and tap water by local women in the usual way, the mortality after 4 washes declined considerably (43.5% and 41.3% for deltamethrin tablets and liquid respectively when washing every second day). Alphacypermethrin showed slightly better results after 3 washes every 7th day compared to deltamethrin tablets (63.8% and 43.3% mortality, respectively). The wash resistance offered by PermaNet was much better and longer lasting: Anopheles mortality after 4 washes was 92.6%, after 10 washes 83.7% and after 20 washes 87.1%. The limitations of commercially available wash-resistant nets are, however, their limited accessibility and the difficulty of replacing all existing bednets with a new product. PMID:12497971

Ordóñez González, José; Kroeger, Axel; Aviña, Ana Isabel; Pabón, Eulides

2002-01-01

123

Gas chromatographic evaluation of pesticide residue contents in nectarines after non-toxic washing treatments  

Microsoft Academic Search

Washing with aqueous solutions of citric acid, ethanol, glycerol, hydrogen peroxide, potassium permanganate, sodium metabisulfite, sodium laurylsulfate (SLS), sodium hypochlorite, and urea is evaluated for pesticide residue reduction in nectarines and compared with simple tap water washing. Residues of pesticides commonly utilized in nectarines (chlorpyrifos, fenarimol, iprodione, malathion, methidathion, myclobutanil, parathion and pirimicarb) are extracted with ethyl acetate and anhydrous

P. Pugliese; J. C. Moltó; P. Damiani; R. Marín; L. Cossignani; J. Mañes

2004-01-01

124

Heat and mass transfer in the system hydrocarbon gas-porous carbon layer-metal and formation of supersaturated solid carbon solutions  

NASA Astrophysics Data System (ADS)

It is shown that the carbon layer formed on the catalytic surface of a metal plays an important role in industrial technologies of obtaining carbon nanofibers. The effective heat conduction of porous carbon samples was measured. A mathematical model of the heat and mass transfer inside a carbon layer has been developed and its stationary solutions were investigated. It is shown that a decrease in the thickness of a porous carbon layer on the surface of a metal as a result of its cleaning and a further growth of this layer lead to the formation of a supersaturated solid solution of carbon in the metal.

Takopulo, D. A.; Fisenko, S. P.

2012-05-01

125

[Distribution patterns of PAHs in soils from coking plant and the particle-size cut points of soil washing].  

PubMed

Soil particle size distribution and contaminants distribution patterns in different soil size fractions are the basis of soil treatability using soil washing method. Soil particle-size cut points are important parameters of soil washing process. According to ex situ soil washing technology, soil samples were collected in a former coking plant. The soil particle size distribution and the concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) in USEPA priority list were analyzed. Tween 80 and Triton X-100 solutions were used to clean the polluted soil with different particle size. Results showed that the total concentrations of 16 PAHs ranged from 6.27 to 40.18 mg/kg dry weight in the six soil size fractions and present a bimodal distribution. The maximum individual PAH concentration mostly occurred in the 250-500 microm size fraction. The lowest individual PAH concentration was in the 50-75 microm size fraction. The removal efficiencies of PAHs in different soil size fractions depended on their initial concentrations and the characteristics of soil. The PAHs removal efficiencies in coarser size fractions were lower than that in the finer size fractions owing to their higher organic carbon content. Based on the removal efficiency of PAHs in each soil size fractions by surfactant solution and the requirements of waste volume reduction, 50 microm was determined as the particle-size cut point. Then, 82.95% volume reduction can be achieved. PMID:21717762

Li, He-Lian; Chen, Jia-Jun; Wu, Wei; Piao, Xue-Song; Jiang, Lin; Shi, Zhen-Tian; Sun, Tian-Wei

2011-04-01

126

Corrosion Behavior of Mild Carbon Steel in Ethanolic Solutions  

Microsoft Academic Search

Electrochemical evaluation of ASTM A36 steel was performed in ethanolic solutions containing small concentrations of water\\u000a ranging from 0 to 10 vol.%. Electrochemical techniques such as open circuit potential (OCP), electrochemical impedance spectroscopy\\u000a (EIS), and potentiodynamic polarization were utilized to analyze corrosion parameters. A fixed concentration of chloride,\\u000a as per the ASTM specification for fuel grade ethanol, was added to increase

Shaily M. Bhola; Rahul Bhola; Luke Jain; Brajendra Mishra; David L. Olson

2011-01-01

127

Electrochemical formation of hydroxide for enhancing carbon dioxide and acid gas uptake by a solution  

DOEpatents

A system is described for forming metal hydroxide from a metal carbonate utilizing a water electrolysis cell having an acid-producing anode and a hydroxyl-producing cathode immersed in a water solution of sufficient ionic content to allow an electric current to pass between the hydroxyl-producing cathode and the acid-producing anode. A metal carbonate, in particular water-insoluble calcium carbonate or magnesium carbonate, is placed in close proximity to the acid-producing anode. A direct current electrical voltage is provided across the acid-producing anode and the hydroxyl-producing cathode sufficient to generate acid at the acid-producing anode and hydroxyl ions at the hydroxyl-producing cathode. The acid dissolves at least part of the metal carbonate into metal and carbonate ions allowing the metal ions to travel toward the hydroxyl-producing cathode and to combine with the hydroxyl ions to form the metal hydroxide. The carbonate ions travel toward the acid-producing anode and form carbonic acid and/or water and carbon dioxide. Among other uses, the metal hydroxide formed can be employed to absorb acid gases such as carbon dioxide from a gas mixture. The invention can also generate hydrogen and oxidative gases such as oxygen or chlorine.

Rau, Gregory Hudson (Castro Valley, CA)

2012-05-15

128

Wastewater washing screens out solids  

SciTech Connect

Screening, as practiced by most municipal wastewater treatment plants, involves the manual or mechanical separation of all undesirable solids that flow into the sewer system. This consists of putresible or rotting material and inert solids such as paper, food, leaves, plastics, rubber, rocks, glass, metal and cigarette butts. These constituents, if not removed, clog downstream equipment and put a heavy load on aeration basins, dissolved air flotation equipment and digesters. Screenings washing is just entering the U.S. market with numerous benefits including increased efficiency, economics, safer work environment, and the ability to meet more stringent regulations.

Mitchell, D.G. [Hycor Corp., Lake Bluff, IL (United States)

1994-09-01

129

Methods of pretreating comminuted cellulosic material with carbonate-containing solutions  

DOEpatents

Methods of pretreating comminuted cellulosic material with an acidic solution and then a carbonate-containing solution to produce a pretreated cellulosic material are provided. The pretreated material may then be further treated in a pulping process, for example, a soda-anthraquinone pulping process, to produce a cellulose pulp. The pretreatment solutions may be extracted from the pretreated cellulose material and selectively re-used, for example, with acid or alkali addition, for the pretreatment solutions. The resulting cellulose pulp is characterized by having reduced lignin content and increased yield compared to prior art treatment processes.

Francis, Raymond

2012-11-06

130

Studies on Oxidation, Reduction and Adsorption of Metallic Ions in Aqueous Solutions by Activated Carbons and the Like.  

National Technical Information Service (NTIS)

Activated carbons were used for oxidation, reduction and adsorption of metallic ions in aqueous solutions to separate, refine and recover them. Activated carbons promote the oxidation reaction of Fe(2+) to Fe(3+) and hexacyanoferrate (II) to hexacyanoferr...

I. Saito

1989-01-01

131

Density and viscosity of some partially carbonated aqueous alkanolamine solutions and their blends  

SciTech Connect

Very little information is available concerning the effect of acid gas loading on the physical properties of amine-treating solutions flowing through the absorption and regeneration columns used in gas processing. The densities and viscosities of partially carbonated monoethanolamine (MEA), diethanolamine (DEA), and N-methyldiethanolamine (MDEA) solutions were measured at 298 K. With increasing carbon dioxide loadings, significant increases in both density and viscosity were observed. These results were combined with literature data to produce correlations for alkanolamine solution density and viscosity as a function of amine concentration, carbon dioxide loading, and temperature. The resulting single-amine correlations were used to predict the densities and viscosities of DEA + MDEA and MEA + MDEA blends. Predictions are compared with data measured for these blends.

Weiland, R.H.; Dingman, J.C.; Cronin, D.B.; Browning, G.J. [Optimized Gas Treating, Inc., Houston, TX (United States)] [Optimized Gas Treating, Inc., Houston, TX (United States)

1998-05-01

132

Reactions of rare earth flourides with sodium carbonate and hydroxide solutions  

SciTech Connect

Exchange interactions of sparingly soluble rare earth (RE) compounds such as fluorides, carbonates, and hydroxides in aqueous media are studied. The starting materials were fluorides of individual RE, obtained by precipitation with hydrofluoric acid from solutions of RE nitrates, which were prepared from the corresponding oxides of 99.9% and taken to the air-dry state, and also cp sodium carbonate and hydroxide. The solution compositions were determined by titration: NaOH and Na/sub 2/CO/sub 3/ with hydrochloric acid, and NaF with Th(NO/sub 3/)/sub 4/ solution. The equilibrium concentrations of NaF and naOH (or Na/sub 2/CO/sub 3/) in the systems studied at 90 degrees are given, which shows that in the La-Lu series the degree of conversion of RE fluorides into hydroxides increases, and into carbonates decreases.

Chuviliana, E.L.; Baryshnikov, N.V.; Poletaev, I.F.

1986-01-10

133

Removal of Cr(VI) from aqueous solution by adsorption onto activated carbon  

Microsoft Academic Search

Activated carbon (AC) prepared from coconut tree sawdust was used as an adsorbent for the removal of Cr(VI) from aqueous solution. Batch mode adsorption studies were carried out by varying agitation time, initial Cr(VI) concentration, carbon concentration and pH. Langmuir and Freundlich adsorption isotherms were applied to model the adsorption data. Adsorption capacity was calculated from the Langmuir isotherm and

K. Selvi; S. Pattabhi; K. Kadirvelu

2001-01-01

134

Evolution of pH and chemical composition of pore solution in carbonated concrete  

Microsoft Academic Search

An investigation of carbonation in concrete, the pH and chemical composition change of the pore solution in concrete with different degrees of carbonation, was presented. The concrete samples were manufactured using ordinary portland cement and fly ash with dimension of 100mm diameter by 3mm in height, and six different mix proportions. The concrete samples were exposed to the environment (CO2

Qi Pu; Linhua Jiang; Jinxia Xu; Hongqiang Chu; Yi Xu; Yan Zhang

135

Mechanism of adsorption and electrosorption of bentazone on activated carbon cloth in aqueous solutions  

Microsoft Academic Search

An electrochemical technique has been applied to enhance the removal of a common herbicide (bentazone) from aqueous solutions using an activated carbon cloth as electrode. A pH increase from acidic to basic reduces the uptake, with capacities going from 127 down to 80mg\\/g at pH 2 and 7, respectively. Increasing the oxygen content of the carbon cloth causes a decrease

Conchi O. Ania; François Béguin

2007-01-01

136

[BMIM]BF 4 ionic liquids as effective inhibitor for carbon steel in alkaline chloride solution  

Microsoft Academic Search

The inhibition action of 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4) ionic liquids towards carbon steel corrosion in alkaline chloride solution was investigated by electrochemical measurements. The morphology of the surface was examined by atomic force microscopy (AFM), and the surface composition was evaluated via X-ray photoelectron spectroscopy (XPS) as well in order to verify the presence of inhibitor on the carbon steel surface.

Xin Zhou; Huaiyu Yang; Fuhui Wang

2011-01-01

137

Phosphate Removal from Aqueous Solution Using Coir-Pith Activated Carbon  

Microsoft Academic Search

The present study deals with the removal of phosphates from aqueous solution using activated carbon developed from coir pith. Batch adsorption experiments were performed to delineate the effect of initial pH, contact time, adsorbent dose and temperature on the removal of phosphates by coir-pith activated carbon (CAC) (activated by H2SO4). The removal was found to be maximum in the pH

Pradeep Kumar; S. Sudha; Shri Chand; Vimal Chandra Srivastava

2010-01-01

138

Dry-spraying of ascorbic acid or acetaminophen solutions with supercritical carbon dioxide  

NASA Astrophysics Data System (ADS)

Carbon dioxide is a very poor solvent for many organic compounds, which makes it a good anti-solvent. When a solution is sprayed into carbon dioxide vapour the anti-solvent reduces the solubility within several tens of milliseconds and the solute precipitates. Two distinct regions can be identified, below and above the mixture critical pressure. Below this critical pressure the yield remains relatively low and the process is not well controlled. Above the critical pressure small crystals are obtained of about 2 ?m with a yield of 90%.

Wubbolts, F. E.; Bruinsma, O. S. L.; van Rosmalen, G. M.

1999-03-01

139

Process for the purification of solutions containing alkali metal carbonate, sulphate, hydroxide or possibly hydrogen carbonate, and one at least of the metals vanadium, uranium and molybdenum  

Microsoft Academic Search

A process is claimed for extracting molybdenum from aqueous solutions containing alkali metal carbonate, sulphate, hydroxide or hydrogen carbonate and, primarily, one at least of the metals belonging to the group formed by vanadium, uranium and molybdenum, in the form of alkali metal salts, and mineral and\\/or organic impurities. The said solutions result from an ore attack cycle and are

P. Maurel; F. Nicolas

1983-01-01

140

Inhibition of carbon steel corrosion by azathione derivatives in organic acid solutions  

Microsoft Academic Search

Purpose – The purpose of this paper is to investigate the inhibitive effect of azathiones, namely cyclopentyl-tetrahydro-azathione, cyclohexyl-tetrahydro-azathione and isobutyl-methyl-tetrahydro-azathione on the corrosion of carbon steel in formic and acetic acid solution. The effect of inhibitor concentration, immersion time, acid concentration, and solution temperature on the inhibition efficiencies of the selected azathiones were studied systematically. Design\\/methodology\\/approach – The synthesis of

Sadaf Khan; M. Z. A. Rafiquee; Nidhi Saxena; M. A. Quraishi

2009-01-01

141

Inhibitory mechanism of low-carbon steel corrosion by mimosa tannin in sulphuric acid solutions  

Microsoft Academic Search

Mimosa tannin was investigated as inhibitor of low-carbon steel sulphuric acid corrosion in concentrations from 10-5 to 10-1 mol L-1, at the temperature of 298 K in the solutions of pH 1, 2 and 3. The inhibitor effectiveness increases with increase in concentration. The adsorptive behaviour of mimosa tannin in solutions of pH 1 and 2 may be approximated, both

S. Martinez; I. Štern

2001-01-01

142

External-Noise-Induced Small-Signal Detection with Solution-Gated Carbon Nanotube Transistor  

Microsoft Academic Search

A solution-gated carbon nanotube field-effect transistor (CNTFET) based on stochastic resonance (SR) was investigated in order to enhance small-signal detection under ambient noise conditions. When noise of optimal intensity was introduced at the reference electrode in a nonlinear CNTFET, the electric double layer in the solution was modulated, resulting in SR behavior. Moreover, when the CNTFET was used as a

Yasufumi Hakamata; Yasuhide Ohno; Kenzo Maehashi; Koichi Inoue; Kazuhiko Matsumoto

2011-01-01

143

Solution-processed flexible transparent conductors based on carbon nanotubes and silver grid hybrid films.  

PubMed

In a simple, cost-effective, and solution-based process, a thin-film of single-walled carbon nanotubes is hybridized on a PET film which has been patterned with solution self-assembled Ag nanoparticles. Such a flexible and transparent electrode exhibits a sheet resistance down to ?5.8 ? sq(-1) at ?83.7% optical transmittance. The hybrid films are stable under ambient conditions and offer excellent bendability. PMID:24675812

Wang, Jing; Zhang, Jintao; Sundramoorthy, Ashok Kumar; Chen, Peng; Chan-Park, Mary B

2014-05-01

144

Extraction of lanthanides from acidic solution using tributyl phosphate modified supercritical carbon dioxide  

Microsoft Academic Search

The feasibility of using supercritical carbon dioxide as a substitute extraction solvent in nuclear reprocessing was tested by the extraction of lanthanide ions from acidic solution. Lanthanides were extracted from 6 M HNO[sub 3]-3 M LiNO[sub 3] solutions using tributyl phosphate- (TBP-) modified CO[sub 2]. Synergistic effects were also investigated using a combination of thenoyltrifluoroacetone (TTA) and TBP-modified CO[sub 2

K. E. Laintz; E. Tachikawa

1994-01-01

145

Solubility of mixtures of hydrogen sulfide and carbon dioxide in aqueous N-methyldiethanolamine solutions  

Microsoft Academic Search

Aqueous solutions of alkanolamines are commonly used to strip acid gases (H[sub 2]S and CO[sub 2]) from streams contaminated with these components. The two most widely used amines are monoethanolamine (MEA) and diethanolamine (DEA). The solubilities of mixtures of hydrogen sulfide and carbon dioxide in a 35 wt% (3.04 kmol\\/m[sup 3]) aqueous solution of N-methyldiethanolamine at 40 and 100C have

Fang Yuan Jou; John J. Carroll; Alan E. Mather; Frederick D. Otto

1993-01-01

146

Solubility of mixtures of hydrogen sulfide and carbon dioxide in aqueous solutions of triethanolamine  

Microsoft Academic Search

Aqueous alkanolamine solutions are commonly used for the removal of HâS and COâ from natural gas streams. The solubility of mixtures of hydrogen sulfide and carbon dioxide in three triethanolamine solutions, (2.0, 3.5, and 5.0) mol\\/dm³, has been determined at temperatures of 50 C, 75 C, and 100 C at partial pressures up to 5,490 kPa.

Fang-Yuan Jou; Frederick D. Otto; Alan E. Mather

1996-01-01

147

Three Activities: One Hand Washes Another, I'm All Washed Up and Who is All Washed Up?  

NSDL National Science Digital Library

ATEEC presents this problem-based lesson plan on risk assessment of environmental health issues. Students will study infectious diseases, particularly those spread via vector-borne, food-borne and water-borne means. They will learn about environmental exposures which cause various infectious diseases. The lesson consists of three individual activities: One Hand Washes Another, I'm All Washed Up... and Who is All Washed Up? Each activity stresses the importance of hand washing. Detailed instructions are provided for each activity. This resource is free to download. Users must first create a login with ATEEC's website to access the file.

2013-07-23

148

Carbon-13 NMR characterization of actinyl(VI) carbonate complexes in aqueous solution  

SciTech Connect

The uranyl(VI) carbonate system has been re-examined using {sup 13}C NMR of 99.9% {sup 13}C-enriched U{sup VI}O{sub 2} ({sup 13}CO{sub 3}){sub 3}{sup 4{minus}} in millimolar concentrations. By careful control of carbonate ion concentration, we have confirmed the existence of the trimer, and observed dynamic equilibrium between the monomer and the timer. In addition, the ligand exchange reaction between free and coordinated carbonate on Pu{sup VI}O{sub 2}({sup 13}CO{sub 3}){sub 3}{sup 4{minus}} and Am{sup VI}O{sub 2}({sup 13}CO{sub 3}){sub 3}{sup 4{minus}} systems has been examined by variable temperature {sup 13}C NMR line-broadening techniques {sup 13}C NMR line-broadening techniques. A modified Carr-Purcell-Meiboom-Gill NMR pulse sequence was written to allow for experimental determination of ligand exchange parameters for paramagnetic actinide complexes. Preliminary Eyring analysis has provided activation parameters of {Delta}G{sup {double dagger}}{sub 295} = 56 kJ/M, {Delta}H{sup {double dagger}} = 38 kJ/M, and {Delta}S{sup {double dagger}} = {minus}60 J/M-K for the plutonyl triscarbonate system, suggesting an associative transition state for the plutonyl (VI) carbonate complex self-exchange reaction. Experiments for determination of the activation parameters for the americium (VI) carbonate system are in progress.

Clark, D.L.; Hobart, D.E.; Palmer, P.D. (Los Alamos National Lab., NM (United States)); Sullivan, J.C. (Argonne National Lab., IL (United States)); Stout, B.E. (Cincinnati Univ., OH (United States). Dept. of Chemistry)

1992-01-01

149

Carbon-13 NMR characterization of actinyl(VI) carbonate complexes in aqueous solution  

SciTech Connect

The uranyl(VI) carbonate system has been re-examined using {sup 13}C NMR of 99.9% {sup 13}C-enriched U{sup VI}O{sub 2} ({sup 13}CO{sub 3}){sub 3}{sup 4{minus}} in millimolar concentrations. By careful control of carbonate ion concentration, we have confirmed the existence of the trimer, and observed dynamic equilibrium between the monomer and the timer. In addition, the ligand exchange reaction between free and coordinated carbonate on Pu{sup VI}O{sub 2}({sup 13}CO{sub 3}){sub 3}{sup 4{minus}} and Am{sup VI}O{sub 2}({sup 13}CO{sub 3}){sub 3}{sup 4{minus}} systems has been examined by variable temperature {sup 13}C NMR line-broadening techniques {sup 13}C NMR line-broadening techniques. A modified Carr-Purcell-Meiboom-Gill NMR pulse sequence was written to allow for experimental determination of ligand exchange parameters for paramagnetic actinide complexes. Preliminary Eyring analysis has provided activation parameters of {Delta}G{sup {double_dagger}}{sub 295} = 56 kJ/M, {Delta}H{sup {double_dagger}} = 38 kJ/M, and {Delta}S{sup {double_dagger}} = {minus}60 J/M-K for the plutonyl triscarbonate system, suggesting an associative transition state for the plutonyl (VI) carbonate complex self-exchange reaction. Experiments for determination of the activation parameters for the americium (VI) carbonate system are in progress.

Clark, D.L.; Hobart, D.E.; Palmer, P.D. [Los Alamos National Lab., NM (United States); Sullivan, J.C. [Argonne National Lab., IL (United States); Stout, B.E. [Cincinnati Univ., OH (United States). Dept. of Chemistry

1992-07-01

150

Release of titanium dioxide from textiles during washing.  

PubMed

Nano-TiO(2) has the highest production of all nanomaterials, and pigment-TiO(2) is a commodity used on the million tons/year scale. Information on the release of TiO(2) from consumer products is therefore an important part of analyzing the potential environmental exposure to TiO(2). For this study, we investigated the release of TiO(2) from six different functional textiles during washing. TiO(2) is used in textiles because of its UV-absorbing properties and as pigment. Analysis of fiber cross sections showed that the TiO(2) was contained in the fiber matrix. The sun-protection textiles had Ultraviolet Protection Factors that were between 58 and 6100 after washing and therefore above the labeled factor of 50+. Five of the textiles (sun-protection clothes) released low amounts of Ti (0.01 to 0.06 wt % of total Ti) in one wash cycle. One textile (with antimicrobial functionality) released much higher amounts of Ti (5 mg/L, corresponding to 3.4 wt % of total Ti in one wash cycle). Size fractionation showed that about equal amounts were released as particles below and above 0.45 ?m. After 10 washings, only in two textiles significantly lower Ti contents were measured. Electron microscopy showed that the TiO(2) particles released into washing solution had a roundish appearance with primary particle sizes between 60 and 350 nm that formed small aggregates with up to 20 particles. The results indicate that functional textiles release some TiO(2) particles, but that the amounts are relatively low and mostly not in the nanoparticulate range. PMID:22746197

Windler, L; Lorenz, C; von Goetz, N; Hungerbühler, K; Amberg, M; Heuberger, M; Nowack, B

2012-08-01

151

Wash water waste pretreatment system  

NASA Technical Reports Server (NTRS)

Investigations were completed on wash waters based on each candidate personal cleansing agent. Evaluations of coagulants, antifoam agents, and the effect of promising antifoams on the chemical precipitation were included. Based on these evaluations two candidate soaps as well as their companion antifoam agents were selected for further work. Operating parameters included the effect of soap concentration, ferric chloride concentration, duration of mixing, and pore size of depth filters on the degree of soap removal. The effect of pressure on water flow through filter cartridges and on the rate of decline of water flow was also investigated. The culmination of the program was the recommendation of a pretreatment concept based on chemical precipitation followed by pressure filtration.

1977-01-01

152

OPTIMIZATION OF THE WASH-OFF METHOD FOR MEASURING AEROSOL CONCENTRATIONS  

EPA Science Inventory

Using the fluorescence-washing technique, oleic acid particles tagged with uranine were extracted and analyzed fluorometrically. The possible sources of errors in the technique were evaluated in this study. First, the sensitivity of uranine fluorescence in different solutions ...

153

Potential benefit of surfactants in a hydrocarbon contaminated soil washing process: fluorescence spectroscopy based assessment.  

PubMed

Soil washing is an ex situ soil remediation treatment process. The purpose of soil washing is to clean the major gravel and sand fractions, concentrating contamination into the fine silt and clay fractions. The addition of surfactants can improve the efficiency of this method. Here we report the use of UV fluorescence spectroscopy to assess the hydrocarbon cleaning process as a rapid and cost effective alternative to gas chromatography. Three wash solutions were tested on a total petroleum hydrocarbon contaminated soil: water, Sea Power 101 (SP101) at 1% (v/v) and Tween80 at 0.5% (w/v). The most effective to wash the gravel and sand was SP101 (54 and 65% improvement over the water only wash, respectively) which moved contamination to the silt fraction (94% of contaminants). Tween80 appeared not to enhance TPH removal efficiency from the gravel and sand fractions but did concentrate TPH in the effluent (95% more than water wash). In addition to TPH removal from gravel and sand, SP101 also showed potential benefit in the soil washing sedimentation process, enhancing sludge/water volume separation by 10% over the water only wash. In summary, fluorescence spectroscopy proved an effective technique to compare TPH removal efficiencies as part of soil washing laboratory based treatability testing. PMID:22503218

Uhmann, Amandine; Aspray, Thomas J

2012-06-15

154

Algebraic solution of transcritical carbon dioxide flow through adiabatic capillary tubes  

Microsoft Academic Search

This paper outlines an algebraic model for simulating the transcritical expansion of carbon dioxide through adiabatic capillary tubes. The model was put forward based on the analytical solution of the momentum conservation equation assuming an isenthalpic expansion process. The theoretical model predictions were compared with 66 experimental data points covering different operating conditions and tube geometries. A good agreement between

Christian J. L. Hermes; Diogo L. da Silva; Cláudio Melo; Joaquim M. Gonçalves; Gustavo C. Weber

2009-01-01

155

Stress Corrosion Cracking Characteristics of a Range of Pipeline Steels in Carbonate-Bicarbonate Solution  

Microsoft Academic Search

Stress corrosion cracking (SCC) characteristics of a range of pipeline steels immersed in a carbonate-bicarbonate solution were studied in terms of the deleterious effects of small-amplitude cyclic loading on threshold stress, together with the increase of crack nucleation and the decrease of average crack growth rates with increasing test times. Data were reported on conditions for coalescence or otherwise of

R. N. Parkins; W. K. Blanchard Jr; E. N. Belhimer

1993-01-01

156

Adsorption of bentazon and propanil from aqueous solutions at the high area activated carbon-cloth  

Microsoft Academic Search

Removal of the pesticides bentazon and propanil from single and bisolute solutions by adsorption at the high area activated carbon-cloth was investigated. Kinetics of adsorption was followed and adsorption isotherms of the two pesticides were determined. A special V-shaped cell with an UV cuvette attached to it was used for adsorption studies. With this cell it was possible to follow

Erol Ayranci; Numan Hoda

2004-01-01

157

Elution of zinc in dust discharged from electric arc furnace in carbonic acid solution  

Microsoft Academic Search

The dust discharged from an electric arc furnace (EAF) is a valuable resource of zinc. As a fundamental study of extraction of zinc, iron and chlorine in the EAF dust, the elution behavior of them in carbonic acid solution was studied. The influence of the weight of the EAF dust on the elution behavior was examined in this study. Experiment

S Yokoyama; T Sasaki; J Sasano; M Izaki

2012-01-01

158

Solution Casting and Transfer Printing Single-Walled Carbon Nanotube Films  

Microsoft Academic Search

This paper presents methods for solution casting and transfer printing collections of individual single-walled carbon nanotubes (SWNTs) onto a wide range of substrates, including plastic sheets. The deposition involves introduction of a solvent that removes surfactant from a suspension of SWNTs as it is applied to a substrate. The subsequent controlled flocculation (cF) produces films of SWNTs with densities that

Matthew A. Meitl; Yangxin Zhou; Anshu Gaur; Seokwoo Jeon; Monica L. Usrey; Michael S. Strano; John A. Rogers

2004-01-01

159

Oxidation of activated carbon with aqueous solution of sodium dichloroisocyanurate: Effect on ammonia adsorption  

Microsoft Academic Search

An activated carbon has been oxidized with 1–10wt% aqueous solutions of sodium dichlororisocyanurate (DCI) to introduce oxygen and chlorine surface groups by chemisorption; the formation of chlorine surface groups is important when the concentration of DCI is high, the modification of the microporosity being small. The range of stability of the groups is wide, from groups decomposing at high temperature

M. Molina-Sabio; M. Gonçalves; F. Rodríguez-Reinoso

2011-01-01

160

Dispersion of Multi?walled Carbon Nanotubes in Aqueous Pluronic F127 Solutions for Biological Applications  

Microsoft Academic Search

Because mass?produced carbon nanotubes (CNTs) are strongly aggregated and highly hydrophobic, processes to make them water soluble are required for biological applications. Suspensions in surfactant solutions are often employed. Among these, Pluronic F127 appear to be highly biocompatible if used at low concentrations. Starting from these results, this work involves a systematic study to clarify the dispersion behaviour of CNTs

Gianni Ciofani; Vittoria Raffa; Virginia Pensabene; Arianna Menciassi; Paolo Dario

2009-01-01

161

Sorption of metal ions from multicomponent aqueous solutions by activated carbons produced from waste  

SciTech Connect

Activated carbons produced by thermal treatment of a mixture of sunflower husks, low-grade coal, and refinery waste were studied as adsorbents of transition ion metals from aqueous solutions of various compositions. The optimal conditions and the mechanism of sorption, as well as the structure of the sorbents, were studied.

Tikhonova, L.P.; Goba, V.E.; Kovtun, M.F.; Tarasenko, Y.A.; Khavryuchenko, V.D.; Lyubchik, S.B.; Boiko, A.N. [National Academy of Science Ukraine, Kiev (Ukraine). Institute of Coal Chemistry

2008-08-15

162

Investigations of optical limiting mechanisms in carbon particle suspensions and fullerene solutions  

NASA Astrophysics Data System (ADS)

Liquid suspensions of carbon act as optical limiters in the presence of high-intensity Q-switched laser pulses. The optical limiting is a result of optical breakdown, which is initiated by absorption in the small carbon particles. We measured the total energy scattered during the breakdown process and the angular distribution of the scattered light as a function of input energy. We also compared the relative scattered energy created during limiting in the carbon suspensions with that generated in solutions of fullerenes in toluene. The ratio of scattered to absorbed energy is different for the suspensions from that for the fullerene solutions, indicating that different mechanisms dominate the limiting processes in the two media.

Nashold, Karen M.; Powell Walter, Diane

1995-07-01

163

Adsorption of synthetic organic chemicals by carbon nanotubes: Effects of background solution chemistry.  

PubMed

With the significant increase in the production and use of carbon nanotubes (CNTs), they will be inevitably released into aquatic environments. Therefore, the fate and transport of CNTs in aqueous solutions have attracted extensive attention. In the present work, the effects of natural organic matter (NOM), solution pH and ionic strength on adsorption of three synthetic organic chemicals (SOCs) by both pristine and surface functionalized single-walled carbon nanotubes (SWNTs) and multi-walled carbon nanotubes (MWNTs) were investigated. The three SOCs (phenanthrene, biphenyl, and 2-phenylphenol) with different planarity, polarity, and hydrogen/electron-donor/acceptor ability, representing typical scenarios for the SOC-CNT interactions, were employed as probe molecules. Among the three background solution characteristics examined, NOM showed the most significant effect on SOC adsorption, while solution pH and ionic strength exhibited minimal or negligible impacts. The presence of NOM greatly suppressed the SOC adsorption by CNTs, and the impact on the SWNTs was higher than that on the MWNTs. The planarity and hydrophobicity of SOCs were two important factors determining the effects of NOM, solution pH and ionic strength on their adsorption by CNTs. PMID:20071001

Zhang, Shujuan; Shao, Ting; Bekaroglu, S Sule Kaplan; Karanfil, Tanju

2010-03-01

164

Free energetics of carbon nanotube association in pure and aqueous ionic solutions.  

PubMed

Carbon nanotubes are a promising platform across a broad spectrum of applications ranging from separations technology, drug delivery, to bio(electronic) sensors. Proper dispersion of carbon nanotube materials is important to retaining the electronic properties of nanotubes. Experimentally it has been shown that salts can regulate the dispersing properties of CNTs in aqueous system with surfactants (Niyogi, S.; Densmore, C. G.; Doorn, S. K. J. Am. Chem. Soc.2009, 131, 1144-1153); details of the physicochemical mechanisms underlying such effects continue to be explored. We address the effects of inorganic monovalent salts (NaCl and NaI) on dispersion stability of carbon nanotubes.We perform all-atom molecular dynamics simulations using nonpolarizable interaction models to compute the potential of mean force between two (10,10) single-walled carbon nanotubes (SWNTs) in the presence of NaCl/NaI and compare to the potential of mean force between SWNTs in pure water. Addition of salts enhances stability of the contact state between two SWNT's on the order of 4 kcal/mol. The ion-specific spatial distribution of different halide anions gives rise to starkly different contributions to the free energy stability of nanotubes in the contact state. Iodide anion directly stabilizes the contact state to a much greater extent than chloride anion. The enhanced stability arises from the locally repulsive forces imposed on nanotubes by the surface-segregated iodide anion. Within the time scale of our simulations, both NaI and NaCl solutions stabilize the contact state by equivalent amounts. The marginally higher stability for contact state in salt solutions recapitulates results for small hydrophobic solutes in NaCl solutions (Athawale, M. V.; Sarupria, S.; Garde, S. J. Phys. Chem. B2008, 112, 5661-5670) as well as single-walled carbon nanotubes in NaCl and CaCl2 aqueous solutions. PMID:22780909

Ou, Shuching; Patel, Sandeep; Bauer, Brad A

2012-07-19

165

Physical solubility of hydrogen sulfide and carbon dioxide in alkanolamine solutions  

SciTech Connect

The study was undertaken to develop a method that would make direct measurements of acid gases, hydrogen sulfide and carbon dioxide, physical solubilities in aqueous alkanolamine solutions possible. Hydrogen sulfide and carbon dioxide physical solubilities in 20, 35, and 50% by weight diethanolamine aqueous solutions were measured. The solubility measurements were made at acid gas partial pressure up to 1000 psia and temperatures of 80, 150, 240 F. The solubility of nitrous oxide in water and in protonated diethanolamine solution was also determined at 80 F. A method that allows for direct measurements of acid gases physical solubilities has been developed. The method eliminates amines reactivity with acid gases by protonating the amines prior to their contact with acid gases. CO{sub 2} physical solubility in aqueous DEA solutions occurs mainly in the water portion of the solution. Therefore, the physical solubility of CO{sub 2} in an aqueous amine solution must be corrected based on the fraction of water in the solution. However, H{sub 2}S physical solubility in aqueous DEA solutions is the same as H{sub 2}S solubility in water. At any acid gas partial pressure, the physical solubility of H{sub 2}S is higher than that of CO{sub 2} for the same solution concentration and for the same temperature. This is also true for their solubilities is pure water. The ratio of CO{sub 2} to H{sub 2}S physical solubility to N{sub 2}O solubility in aqueous DEA solutions is not the same as their ratio in pure water.

Abu-Arabi, M.K.

1988-01-01

166

Soil washing: A preliminary assessment of its applicability to Hanford  

SciTech Connect

Soil washing is being considered for treating soils at the US Department of Energy's (DOE) Hanford Site. As a result of over 50 years of operations to produce plutonium for the US Department of Defense and research for DOE, soils in areas within the Site are contaminated with hazardous wastes and radionuclides. In the soil washing process, contaminated soil is mixed with a liquid and then physically and/or chemically treated to dissolve the contaminants into solution and/or concentrate them in a small fraction of the soil. The purpose of this procedure is to separate the contaminants from the bulk of the soil. The key to successful application is to match the types of contaminants and soil characteristics with physical-chemical methods that perform well under the existing conditions. The applicability of soil washing to Hanford Site contaminated soils must take into account both the characteristics of the oil and the type of contamination. Hanford soils typically contain up to 90% sand, gravel, and cobbles, which generally are favorable characteristics for soil washing. For example, in soil samples from the north pond in the 300 Area, 80% to 90% of the soil particles were larger than 250 {mu}m. The principal contaminants in the soil are radionuclides, heavy metals, and nitrate and sulfate salts. For most of the sites, organic contaminants are either not present or are found in very low concentration. 28 refs., 5 figs., 10 tabs.

Gerber, M A; Freeman, H D; Baker, E G; Riemath, W F

1991-09-01

167

Optimizing surfactant concentrations for dispersion of single-walled carbon nanotubes in aqueous solution.  

PubMed

The sonication-centrifugation technique is commonly used for dispersing single-walled carbon nanotubes (SWCNTs) in aqueous surfactant solutions. However, the methodologies and materials used for this purpose are widely varied, and few dispersive agents have been studied systematically. This work describes a systematic study into the ability of some well-known (and some less common) surfactants and polymers to disperse SWCNTs fabricated by two different techniques. UV-vis-NIR absorbance spectra of their supernatant solutions showed that the smaller ionic surfactants were generally more effective dispersants, with larger polymer and surfactant molecules exhibiting a reduced performance for ensembles of carbon nanotubes of smaller average diameter. Optimal surfactant concentrations were established for dispersions of carbon nanotubes produced by the electric arc method in aqueous solutions of sodium dodecylbenzene sulfonate, sodium deoxycholate, Triton X-405, Brij S-100, Pluronic F-127, and polyvinylpyrrolidone. This optimum value was determined as the point at which the relative concentration of nanotubes dispersed is maximized, before flocculation-inducing attractive depletion interactions begin to dominate. The aggregation state of carbon nanotubes dispersed in sodium dodecylbenzene sulfonate was probed by AFM at different stages of rebundling, showing the length dependence of these effects. PMID:20666522

Blanch, Adam J; Lenehan, Claire E; Quinton, Jamie S

2010-08-01

168

Aragonite nanorods in calcium carbonate/polymer hybrids formed through self-organization processes from amorphous calcium carbonate solution.  

PubMed

Nanostructured inorganic/polymer hybrid thin films comprising aragonite nanorods derived from aqueous suspensions of amorphous calcium carbonate (ACC) are prepared. For the formation of calcium carbonate (CaCO?)/polymer hybrids, spincoated and annealed films of poly(vinyl alcohol) (PVA) that function as polymer matrices are soaked in aqueous colloidal solutions dispersing ACC stabilized by poly(acrylic acid) (PAA). In the initial stage, calcite thin films form on the surface. Subsequently, aragonite crystals start to form inside the PVA matrix that contains PVA crystallites which induce aragonite nucleation. Nanostructured hybrids composed of calcite thin films consisting of nanoparticles and assembled aragonite nanorods are formed in the matrices of PVA. PMID:24425526

Kajiyama, Satoshi; Nishimura, Tatsuya; Sakamoto, Takeshi; Kato, Takashi

2014-04-24

169

Competitive adsorption of phenolic compounds from aqueous solution using sludge-based activated carbon.  

PubMed

Preparation of activated carbon from sewage sludge is a promising approach to produce cheap and efficient adsorbent for pollutants removal as well as to dispose of sewage sludge. The first objective of this study was to investigate the physical and chemical properties (BET surface area, ash and elemental content, surface functional groups by Boehm titration and weight loss by thermogravimetric analysis) of the sludge-based activated carbon (SBAC) so as to give a basic understanding of its structure and to compare to those of two commercial activated carbons, PICA S23 and F22. The second and main objective was to evaluate the performance of SBAC for single and competitive adsorption of four substituted phenols (p-nitrophenol, p-chlorophenol, p-hydroxy benzoic acid and phenol) from their aqueous solutions. The results indicated that, despite moderate micropore and mesopore surface areas, SBAC had remarkable adsorption capacity for phenols, though less than PICA carbons. Uptake of the phenolic compound was found to be dependent on both the porosity and surface chemistry of the carbons. Furthermore, the electronegativity and the hydrophobicity of the adsorbate have significant influence on the adsorption capacity. The Langmuir and Freundlich models were used for the mathematical description of the adsorption equilibrium for single-solute isotherms. Moreover, the Langmuir-Freundlich model gave satisfactory results for describing multicomponent system isotherms. The capacity of the studied activated carbons to adsorb phenols from a multi-solute system was in the following order: p-nitrophenol > p-chlorophenol > PHBA > phenol. PMID:21970174

Mohamed, E F; Andriantsiferana, C; Wilhelm, A M; Delmas, H

2011-01-01

170

Contaminant resorption during soil washing  

SciTech Connect

To evaluate the applicability of soil washing to a specific site requires some basic research in how contaminants are bound. Much can be learned from sequential extraction methodology based on micronutrient bioavailability studies wherein the soil matrix is chemically dissected to selectively remove particular fixation mechanisms independently. This procedure uses a series of progressively more aggressive solvents to dissolve the principle phases that make up a soil, however, the published studies do not appear to consider the potential for a contaminant released from one type of site to resorb on another site during an extraction. This physical model assumes no ion exchange or adsorption at sites either previously occupied by other ions, or exposed by the dissolution. Therefore, to make engineering use of the sequential extraction data, the release of contamination must be evaluated relative to the effects of resorption. Time release studies were conducted to determine the optimum duration for extraction to maximize complete destruction of the target matrix fraction while minimizing contaminant resorption. Tests with and without a potassium brine present to inhibit cesium resorption indicated extraction efficiency could be enhanced by as much as a factor of ten using the brine.

Gombert, D.

1993-10-01

171

Linking variability in soil solution dissolved organic carbon to climate, soil type, and vegetation type  

NASA Astrophysics Data System (ADS)

transport of carbon plays an important role in linking the carbon cycles of terrestrial and aquatic ecosystems. There is, however, a lack of information on the factors controlling one of the main C sources of this lateral flux, i.e., the concentration of dissolved organic carbon (DOC) in soil solution across large spatial scales and under different soil, vegetation, and climate conditions. We compiled a database on DOC in soil solution down to 80 cm and analyzed it with the aim, first, to quantify the differences in DOC concentrations among terrestrial ecosystems, climate zones, soil, and vegetation types at global scale and second, to identify potential determinants of the site-to-site variability of DOC concentration in soil solution across European broadleaved and coniferous forests. We found that DOC concentrations were 75% lower in mineral than in organic soil, and temperate sites showed higher DOC concentrations than boreal and tropical sites. The majority of the variation (R2 = 0.67-0.99) in DOC concentrations in mineral European forest soils correlates with NH4+, C/N, Al, and Fe as the most important predictors. Overall, our results show that the magnitude (23% lower in broadleaved than in coniferous forests) and the controlling factors of DOC in soil solution differ between forest types, with site productivity being more important in broadleaved forests and water balance in coniferous stands.

Camino-Serrano, Marta; Gielen, Bert; Luyssaert, Sebastiaan; Ciais, Philippe; Vicca, Sara; Guenet, Bertrand; Vos, Bruno De; Cools, Nathalie; Ahrens, Bernhard; Altaf Arain, M.; Borken, Werner; Clarke, Nicholas; Clarkson, Beverley; Cummins, Thomas; Don, Axel; Pannatier, Elisabeth Graf; Laudon, Hjalmar; Moore, Tim; Nieminen, Tiina M.; Nilsson, Mats B.; Peichl, Matthias; Schwendenmann, Luitgard; Siemens, Jan; Janssens, Ivan

2014-05-01

172

A fresh look at preoperative body washing.  

PubMed

National guidelines do not support preoperative body washing to reduce surgical site infections, instead recommending bathing or showering with soap. Yet preoperative body washing continues to be widely used in many hospitals across Europe. This paper suggests that existing trials of preoperative body washing, upon which guidelines are based, are dated and proposes a new investigation of preoperative body washing using modern definitions of surgical site infection with standardised patient follow up, modern surgical techniques and well designed trials. This paper provides a critique of existing guidelines and describes a randomised trial with 60 participants to compare the effect of soap and two antiseptic washing products on colony forming units (CFUs) for up to six hours. Chlorhexidine gluconate and octenidine were significantly more effective than soap in reducing CFUs in the underarm, and chlorhexidine was significantly more effective than soap in reducing CFUs in the groin. PMID:22448182

Tanner, Judith; Gould, Dinah; Jenkins, Philip; Hilliam, Rachel; Mistry, Neetesh; Walsh, Susannah

2012-01-01

173

A fresh look at preoperative body washing  

PubMed Central

National guidelines do not support preoperative body washing to reduce surgical site infections, instead recommending bathing or showering with soap. Yet preoperative body washing continues to be widely used in many hospitals across Europe. This paper suggests that existing trials of preoperative body washing, upon which guidelines are based, are dated and proposes a new investigation of preoperative body washing using modern definitions of surgical site infection with standardised patient follow up, modern surgical techniques and well designed trials. This paper provides a critique of existing guidelines and describes a randomised trial with 60 participants to compare the effect of soap and two antiseptic washing products on colony forming units (CFUs) for up to six hours. Chlorhexidine gluconate and octenidine were significantly more effective than soap in reducing CFUs in the underarm, and chlorhexidine was significantly more effective than soap in reducing CFUs in the groin.

Tanner, Judith; Gould, Dinah; Jenkins, Philip; Hilliam, Rachel; Mistry, Neetesh; Walsh, Susannah

2012-01-01

174

Galvanic Corrosion of a Carbon Steel-Stainless Steel Couple in Sulfide Solutions  

Microsoft Academic Search

The galvanic corrosion behavior of carbon steel-stainless steel couples with various cathode\\/anode area ratios was investigated\\u000a in S\\u000a 2?-containing solutions, which were in equilibrium with air, by electrochemical measurements, immersion test, and surface characterization.\\u000a It is found that the galvanic corrosion effect on carbon steel anode increases with the cathode\\/anode area ratios, and decreases\\u000a with the increasing concentration of S2?

C. F. Dong; K. Xiao; X. G. Li; Y. F. Cheng

175

Determination of free base in aluminate-carbonate solutions by standard addition method  

SciTech Connect

Alkaline waste solutions from the 200-Area separations processes are analyzed for sodium hydroxide, sodium aluminate, and sodium carbonate by a complicated titration procedure that requires about two hours. Frequently, however, only the sodium hydroxide concentration (i.e., free base) is required. For example, free base is measured to confirm that acidic wastes are neutralized or to verify that stored waste meets technical standards. This memorandum describes a new fifteen-minute standard addition procedure that determines free base in the presence of aluminate and carbonate.

Baumann, E.W.

1983-09-29

176

Adsorption of cadmium and lead onto oxidized nitrogen-doped multiwall carbon nanotubes in aqueous solution: equilibrium and kinetics  

Microsoft Academic Search

Nitrogen-doped multiwall carbon nanotubes (CNx) were chemically oxidized and tested to adsorb cadmium and lead from aqueous\\u000a solution. Physicochemical characterization of carbon nanotubes included morphological analysis, textural properties, and chemical\\u000a composition. In addition, the cadmium adsorption capacity of oxidized-CNx was compared with commercially available activated\\u000a carbon and single wall carbon nanotubes. Carboxylic and nitro groups on the surface of oxidized

Nancy Veronica Perez-Aguilar; Emilio Muñoz-Sandoval; Paola Elizabeth Diaz-Flores; Jose Rene Rangel-Mendez

2010-01-01

177

Static and dynamic adsorption of phenol from aqueous solution using spherical carbon  

NASA Astrophysics Data System (ADS)

The objective of this work is to evaluate spherical carbon and modified spherical carbon for the removal of phenol from aqueous solution in static and dynamic studies under various conditions. It explores mainly two adsorbents, that is, activated spherical carbon (ASC) and modified activated spherical carbon (SSC). SEM characterization of both the adsorbents showed a clear change in the physical and chemical properties of the modified adsorbent from its precursor activated carbon. Both the adsorbents are subjected to static mode adsorption studies and after a comparison based on isotherm analysis; more efficient adsorbent is screened for column mode adsorption studies. The phenol removal increased for modified carbon. The aim of carrying out column mode studies will aid in ascertaining the practical applicability of the adsorbent in the real system and therefore, to assess the effect of various process variables, viz., bed height of the adsorbent, flow rate and initial concentration of the adsorbate on breakthrough time and adsorption capacity. The column studies generated data were modeled using the empirical relationship based on Bohart-Adams model. At the end, the option of regenerating the adsorbent was also explored using sodium hydroxide with the aim of minimize the hazardous generated and also to reuse the adsorbent material for many cycles without affecting original properties. Adsorbent regeneration efficiency of 72% was achieved. This investigation reveals that the material used as an adsorbent is very effective with high adsorption capacities and also possible to use in the real contaminated system.

Bhargavi, R.; Kadirvelu, K.; Kumar, N. S.

2013-06-01

178

Tolerance and Safety of Different Concentrations of Chlorhexidine for Peripartum Vaginal and Infant Washes: HIVNET025  

PubMed Central

Background There is a continuing need to evaluate sustainable interventions for prevention of mother-to-child transmission (MTCT) of HIV type 1. We evaluated different concentrations (0.25%, 1%, and 2%) of chlorhexidine (CHX) for perinatal maternal and infant washes to identify the maximum tolerable concentration of CHX for such an intervention. Methods Women were enrolled during their third trimester at the maternity unit of the Chris Hani Baragwanath Hospital in Soweto, South Africa, and perinatal maternal and infant washes were completed. Subjective maternal symptoms as well as infant examinations were used to assess tolerability of the washes. Results The 0.25% concentration of CHX was well tolerated by the mothers (n = 29). Ten of 79 women (13%) with 1% CHX washes complained of mild vaginal area burning or itching, and washes were stopped in 5 (6%). Twenty-three of 75 women (31%) in the 2% CHX wash group had subjective complaints, and the washes were stopped in 12 (16%). There were no clinical indications of toxicity of the CHX washes among infants. Conclusion A 1% solution of CHX appears to be a safe and tolerable concentration of CHX for consideration in an MTCT prevention trial.

Wilson, Craig M.; Gray, Glenda; Read, Jennifer S.; Mwatha, Anthony; Lala, Sanjay; Johnson, Saul; Violari, Avye; Sibiya, Portia Mabali; Fleming, Thomas R.; Koonce, Ann; Vermund, Sten H.; McIntyre, James

2009-01-01

179

Be 2 (OH) 2 CO 3 solubility in carbonate and fluoride aqueous solutions  

Microsoft Academic Search

Be2(OH)2CO3 solubilities at 25C in 0.7 M NaClO4 solutions containing variable NaHCO3 and Na2CO3 concentrations has been experimentally determined. The solubilities increase with increasing carbonate alkalinity. The results\\u000a of the experiments do not contradict the suggestion that the mixed hydroxocarbonate complex Be2(OH)2CO\\u000a 3\\u000a 2?\\u000a is the major beryllium solute species. At fluoride concentrations higher than 250 ?mol\\/L, the Be2(OH)2CO3 solubilities

V. S. Savenko

2007-01-01

180

Solubility of mixtures of hydrogen sulfide and carbon dioxide in aqueous N-methyldiethanolamine solutions  

SciTech Connect

Aqueous solutions of alkanolamines are commonly used to strip acid gases (H[sub 2]S and CO[sub 2]) from streams contaminated with these components. The two most widely used amines are monoethanolamine (MEA) and diethanolamine (DEA). The solubilities of mixtures of hydrogen sulfide and carbon dioxide in a 35 wt% (3.04 kmol/m[sup 3]) aqueous solution of N-methyldiethanolamine at 40 and 100C have been measured. Partial pressures of the acid gases ranged from 0.006 to 101 kPa at 40C and from 4 to 530 kPa at 100C.

Jou, Fang Yuan; Carroll, J.J.; Mather, A.E.; Otto, F.D. (Univ. of Alberta, Edmonton, Alberta (Canada). Dept. of Chemical Engineering)

1993-01-01

181

Sorption of divalent metal ions from aqueous solution by carbon nanotubes: A review  

Microsoft Academic Search

In this article, the technical feasibility of various kinds of raw and surface oxidized carbon nanotubes (CNTs) for sorption of divalent metal ions (Cd2+, Cu2+, Ni2+, Pb2+, Zn2+) from aqueous solution is reviewed. The sorption mechanisms appear mainly attributable to chemical interactions between the metal ions and the surface functional groups of the CNTs. The sorption capacities of CNTs remarkably

Gadupudi Purnachadra Rao; Chungsying Lu; Fengsheng Su

2007-01-01

182

Activated carbon from coconut coirpith as metal adsorbent: adsorption of Cd(II) from aqueous solution  

Microsoft Academic Search

Activated carbon prepared from coirpith, an agricultural solid waste by-product, has been used for the adsorption of Cd(II) from aqueous solution. Parameters such as the agitation time, metal ion concentration, adsorbent dose and pH were studied. The adsorption data fit well with the Langmuir and Freundlich isotherm models. The adsorption capacity (Q0) calculated from the Langmuir isotherm was 93.4 mg

K. Kadirvelu; C. Namasivayam

2003-01-01

183

Initiation of stress corrosion cracking for pipeline steels in a carbonate-bicarbonate solution  

Microsoft Academic Search

The linearly increasing stress test (LIST) was used to study the stress corrosion cracking (SCC) behavior of a range of pipeline\\u000a steels in carbonate-bicarbonate solution under stress rate control at different applied potentials. Stress corrosion cracking,\\u000a at potentials below -800 mV(SCE), was attributed to hydrogen embrittlement. Stress corrosion cracking, in the potential range\\u000a from about-700 to -500 mV(SCE), was attributed

Z. F. Wang; A. Atrens

1996-01-01

184

Electrochemical studies of the film formation on lithium in propylene carbonate solutions under open circuit conditions  

SciTech Connect

The nature of protective surface layers formed on lithium in propylene carbonate solutions of LiClO/sub 4/ and LiAsF/sub 6/ at open circuit has been investigated by electrochemical pulse measurements and other techniques. The results are consistent with the fast formation of a compact thin layer of Li/sub 2/O by reaction with residual water. This layer acts as a solid ionic conductor. Slow corrosion processes produce a thicker porous overlayer.

Geronov, Y.; Schwager, F.; Muller, R.H.

1981-04-01

185

Thermally and Environmentally Stable Carrier Doping Using a Solution Method in Carbon Nanotube Films  

Microsoft Academic Search

In the present paper, we report the thermal stability of a single-walled carbon nanotube (SWCNT) film that was doped using tetrafluorotetracyano-p-quinodimethane (F4TCNQ). The SWCNTs were doped using a vapor method and a solution method, and their thermostabilities were characterized using a gas chromatography\\/mass spectrometer (GC\\/MS) and resistance measurements. These measurements clearly demonstrated the high thermal stability of F4TCNQ and the

Yorihiko Sasaki; Haruya Okimoto; Kenji Yoshida; Yasuichi Ono; Yoshihiro Iwasa; Taishi Takenobu

2011-01-01

186

INHIBITION OF CARBON STEEL CORROSION BY SOME CYANOACETOHYDRAZIDE DERIVATIVES IN HCl SOLUTION  

Microsoft Academic Search

This article describes an investigation of the corrosion behavior of carbon steel in 2 M HCl solution with the addition of some cyanoacetohydrazide derivatives by weight loss, galvanostatic polarization, and potentiodynamic anodic polarization techniques. The explored methods gave almost similar results. Results obtained reveal that inhibitor (I) is the best inhibitor and the inhibition efficiency (IE%) follows the sequence I > II > III > IV. The

A. S. Fouda; M. Abdallah; A. Attia

2010-01-01

187

Carbon steel corrosion inhibition in hydrochloric acid solution using a reduced Schiff base of ethylenediamine  

Microsoft Academic Search

The behavior of the Schiff base N,N?-bis(salicylidene)-1,2-ethylenediamine (Salen), its reduced form (N,N?-bis(2-hydroxybenzyl)-1,2-ethylenediamine) and a mixture of its preceding molecules, ethylenediamine and salicylaldehyde, as carbon steel corrosion inhibitors in 1molL?1 HCl solution was studied by corrosion potential measurements, potentiodynamic polarization curves, electrochemical impedance spectroscopy and spectrophotometry measurements. The experimental results showed that the reduced Salen presented the highest efficiency among the

Adriana Barbosa da Silva; Eliane D’Elia; José Antonio da Cunha Ponciano Gomes

2010-01-01

188

Inhibition of carbon steel corrosion by 4-vinylbenzyl triphenyl phosphonium chloride in HCl solution  

Microsoft Academic Search

Purpose – The purpose of this paper is to study electrochemically and by weight loss experiments the effect of 4-vinylbenzyl triphenyl phosphonium chloride on the corrosion inhibition of mild steel in 1.0 M HCl solution, which will serve researchers in the field of corrosion. Design\\/methodology\\/approach – Electrochemical and weight loss measurements were carried out on carbon steel specimens in 1.0

Ayssar Nahlé; Ideisan Abu-Abdoun; Ibrahim Abdel-Rahman

2008-01-01

189

The inhibition of low carbon steel corrosion in hydrochloric acid solutions by succinic acid  

Microsoft Academic Search

The effect of succinic acid (SA) on the corrosion inhibition of a low carbon steel (LCS) electrode has been investigated in aerated non-stirred 1.0M HCl solutions in the pH range (2–8) at 25°C. Weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques were applied to study the metal corrosion behaviour in the absence and presence of different concentrations of

Mohammed A. Amin; Sayed S. Abd El-Rehim; E. E. F. El-Sherbini; Rady S. Bayoumi

2007-01-01

190

Mechanism of Pitting Corrosion Prevention by Nitrite in Carbon Steel Exposed to Dilute Salt Solutions  

SciTech Connect

The research has developed a broad fundamental understanding of the inhibition action of nitrite ions in preventing nitrate pitting corrosion of carbon steel tanks containing high-level radioactive waste. This fundamental understanding can be applied to specific situations during waste removal for permanent disposition and waste tank closure to ensure that the tanks are maintained safely. The results of the research provide the insight necessary to develop solutions that prevent further degradation.

Philip E. Zapp; John W. Van Zee

2002-02-01

191

Capacitive deionization of NH 4 ClO 4 solutions with carbon aerogel electrodes  

Microsoft Academic Search

A process for the capacitive deionization of water with a stack of carbon aerogel electrodes has been developed by Lawrence Livermore National Laboratory (LLNL). Unlike ion exchange, one of the more conventional deionization processes, no chemicals are required for regeneration of the system. Electricity is used instead. An aqueous solution of NH4ClO4 is pumped through the electrochemical cell. After polarization,

J. C. Farmer; D. V. Fix; G. V. Mack; R. W. Pekala; J. F. Poco

1996-01-01

192

Removal of methylene blue from aqueous solutions using phosphoric acid activated carbon produced from hazelnut husks  

Microsoft Academic Search

In this study, activated carbon (HHPAAC) was prepared from hazelnut husks using phosphoric acid activation and characterized by some physicochemical analyses. Surface area and zero point charge of pH (pHPZC) were found to be 770?m?g and 4.5, respectively. Removal of methylene blue (MB) from aqueous solution was performed using a batch technique for determination of the effects of initial pH,

Cigdem Ozer; Mustafa Imamoglu; Yasemin Turhan; Fusun Boysan

2012-01-01

193

Biodegradable dissolved organic carbon in forest soil solution and eÄects of chronic nitrogen deposition  

Microsoft Academic Search

Abstract Using a flow-through bioreactor, biodegradable dissolved organic carbon (BDOC) in forest floor solution was determined for a red pine (Pinus resinosa) plantation and a naturally regenerated mixed hardwood forest (dominant species: Quercus velutina, Q. rubra, Acer rubrum, Fagus grandifolia, Prunus serotina). The forests have received chronic-N fertilization at three diÄerent rates (0, 50, 150 kg N ha,à 0:60Ü for

Y. Yano; W. h. Mcdowell; J. d. Aber

194

Biodegradable dissolved organic carbon in forest soil solution and effects of chronic nitrogen deposition  

Microsoft Academic Search

Using a flow-through bioreactor, biodegradable dissolved organic carbon (BDOC) in forest floor solution was determined for a red pine (Pinus resinosa) plantation and a naturally regenerated mixed hardwood forest (dominant species: Quercus velutina, Q. rubra, Acer rubrum, Fagus grandifolia, Prunus serotina). The forests have received chronic-N fertilization at three different rates (0, 50, 150 kg N ha?1 year?1) since 1988.

Y Yano; W. H McDowell; J. D Aber

2000-01-01

195

On the Optimal Design, Performance, and Reliability of Future Carbon Nanotube-Based Interconnect Solutions  

Microsoft Academic Search

In this paper, we develop comprehensive modeling and design techniques for carbon nanotube (CNT)-based interconnects, which we utilize to examine the performance, reliability, and fabrication requirements for future nanotube-based interconnect solutions. We create a generalized model for CNT-based interconnect systems that achieves a high degree of accuracy compared to experimental CNT measurements. Leveraging the model, we develop the first closed-form

Arthur Nieuwoudt; Yehia Massoud

2008-01-01

196

Carbon dioxide as refrigerant for tap water heat pumps: A comparison with the traditional solution  

Microsoft Academic Search

Increased concern about the environmental impact of the refrigeration technology is leading toward design solutions aimed at improving the energy efficiency of the related applications, using eco-friendly refrigerants, i.e. ozone-friendly and with the least possible global warming potential (GWP). In this respect, carbon dioxide (ASHRAE R744) is seen today as one of the most promising refrigerants and is raising great

Luca Cecchinato; Marco Corradi; Ezio Fornasieri; Lorenzo Zamboni

2005-01-01

197

Control the polymorphism and morphology of calcium carbonate precipitation from a calcium acetate and urea solution  

Microsoft Academic Search

Two metastable calcium carbonate polymorphs, rod-like aragonite and spherical vaterite are selectively formed in this study. Aragonite rods were synthesized from a calcium acetate (Ca(AC)2) and urea (CO(NH2)2) solution under a given condition. In contrast, the addition of polyacrylamide (PAM) and oleic acid results in the formation of spherical vaterite. The morphology, size and crystal structure were characterized by means

Chengyu Wang

2008-01-01

198

Filling of Carbon Nanotubes with Compounds in Solution or Melted Phase  

Microsoft Academic Search

\\u000a Since their discovery, carbon nanotubes (CNT) have been found to exhibit remarkable structural, mechanical and electronic\\u000a properties. One such property is the ability to encapsulate foreign materials inside their cylindrical cavity, for application\\u000a in different fields. The procedures to fill CNT may be classified into two main groups: (a) filling in solution, using the\\u000a wet chemistry route and (b) filling

P. Lukanov; C.-M. Tîlmaciu; A. M. Galibert; B. Soula; E. Flahaut

199

Coconut (Cocos Nucifera) Shell Based Activated Carbon for the Removal of Malachite Green Dye From Aqueous Solutions  

Microsoft Academic Search

The adsorption of malachite green (MG) dye using coconut shell based activated carbon (CSAC) was investigated. Operational factors such as effect of pH, initial dye concentration, adsorbent dosage, contact time, and solution temperature on the adsorption process were studied. Solution pH strongly affected the chemistry of both the dye molecule and CSAC in solution. Optimum dye removal was obtained at

Olugbenga Solomon Bello; Mohd Azmier Ahmad

2012-01-01

200

Optimization of mesoporous carbons for efficient adsorption of berberine hydrochloride from aqueous solutions.  

PubMed

Sixteen mesoporous carbon adsorbents were synthesized by varying the ratio of soft to hard templates in order to optimize the pore textural properties of these adsorbents. The mesoporous carbon adsorbents have a high BET specific surface area (1590.3-2193.5m(2)/g), large pore volume (1.72-2.56cm(3)/g), and uniform pore size distribution with a median pore diameter ranging from 3.51nm to 4.52nm. It was observed that pore textural properties of the carbon adsorbents critically depend on the molar ratio of carbon sources to templates, and the hard template plays a more important role than the soft template in manipulating the pore textures. Adsorption isotherms of berberine hydrochloride at 303K were measured to evaluate the adsorption efficacy of these adsorbents. The adsorption of berberine hydrochloride from aqueous solutions on the sixteen mesoporous carbon adsorbents synthesized in this work is very efficient, and the adsorption equilibrium capacities on all samples are more than double the adsorption capacities of berberine hydrochloride of the benchmark adsorbents (polymer resins and spherical activated carbons) at similar conditions. It was observed from the adsorption experiments that the equilibrium adsorption amounts of berberine hydrochloride are strongly correlated with the BET specific surface area and pore volume of the adsorbents. The adsorbent with the highest BET of 2193.5m(2)/g displayed the largest adsorption capacity of 574mg/g at an equilibrium concentration of 0.10mg/mL of berberine hydrochloride in an aqueous solution. PMID:24767505

Li, Yin; Fu, Jie; Deng, Shuguang; Lu, Xiuyang

2014-06-15

201

Nature of Non-Fickian Solute Transport in Complex Heterogeneous Porous Media - Carbonates  

NASA Astrophysics Data System (ADS)

Despite the range of significant practical applications of solute transport, including the long-term fate of nuclear waste repositories, secure storage of CO2 and improved oil recovery, even the qualitative behavior of most rocks is uncertain: vast carbonate sedimentary basins contain more than half the world's current oil reserves yet experimental data on transport in carbonates is scant. The relationship between pore structure, velocity field and transport remains unknown, particularly for heterogeneous carbonates. We simulate solute transport through 3D ?-CT images of different rock samples, representing geological media of increasing pore-scale complexity: a sandpack, a Berea sandstone and a Portland limestone. A finite-difference Stokes solver is employed to compute the flow field and transport particles semi-analytically along streamlines to represent advection with a random motion to model diffusion. We predict the propagators measured on similar cores in Nuclear Magnetic Resonance (NMR) experiments. Dispersion coefficient dependence on Peclet number is shown to have different scaling for complex carbonates. The behavior is explained using continuous time random walks with a truncated power-law distribution of travel times: transport is qualitatively different for the complex limestone compared to the sandstone or sandpack, with long tailing, an almost immobile peak concentration and a very slow approach to asymptotic dispersion. We demonstrate the different nature of non-Fickian transport in carbonates by analyzing the transit time probabilities ?(?) of traveling between two neighboring voxels for Portland carbonate that show an approximately power-law dependence of travel times ?(?) ~ ? -1-? with a slope corresponding to ? = 0.7, as shown in Fig.1. The comparison with ?(?) of the sandpack and Berea sandstone for Pe = ? indicates quantitatively different generic behavior, as the sandpack and sandstone have slope corresponding to ? = 1.8 (two solid parallel lines in the insert in Fig.1). This complex non-Fickian behavior at the pore scale has large implications on modeling of field-scale transport.

Bijeljic, B.; Mostaghimi, P.; Blunt, M. J.

2011-12-01

202

Removal of organic contaminants from aqueous solution by cattle manure compost (CMC) derived activated carbons  

NASA Astrophysics Data System (ADS)

The activated carbons (ACs) prepared from cattle manure compost (CMC) with various pore structure and surface chemistry were used to remove phenol and methylene blue (MB) from aqueous solutions. The adsorption equilibrium and kinetics of two organic contaminants onto the ACs were investigated and the schematic models for the adsorptive processes were proposed. The result shows that the removal of functional groups from ACs surface leads to decreasing both rate constants for phenol and MB adsorption. It also causes the decrement of MB adsorption capacity. However, the decrease of surface functional groups was found to result in the increase of phenol adsorption capacity. In our schematic model for adsorptive processes, the presence of acidic functional groups on the surface of carbon is assumed to act as channels for diffusion of adsorbate molecules onto small pores, therefore, promotes the adsorption rate of both phenol and MB. In phenol solution, water molecules firstly adsorb on surface oxygen groups by H-bonding and subsequently form water clusters, which cause partial blockage of the micropores, deduce electrons from the ?-electron system of the carbon basal planes, hence, impede or prevent phenol adsorption. On the contrary, in MB solution, the oxygen groups prefer to combine with MB + cations than water molecules, which lead to the increase of MB adsorption capacity.

Qian, Qingrong; Chen, Qinghua; Machida, Motoi; Tatsumoto, Hideki; Mochidzuki, Kazuhiro; Sakoda, Akiyoshi

2009-04-01

203

Wash water solids removal system study  

NASA Technical Reports Server (NTRS)

During wash water purification, surfactants tend to precipitate and foul the RO membranes, causing water flux decline and loss of salt rejection. The use of 165 to 190 ppm ferric chloride and optionally 0.25 to 1.0 ppm polymeric flocculate precipitates 92 to 96 percent of the surfactant from an Olive Leaf Soap based wash water. Crossflow filtration and pressure filtration yield good soap rejection at high water flux rates. Post-treatment of the chemically pretreated and filtered wash water with activated charcoal removes the residual soap down to an undetectable level.

1974-01-01

204

Molecular speciation and mesoscale clustering in formaldehyde-methanol-water solutions in the presence of sodium carbonate.  

PubMed

Nanoporous organic gels can be synthesized from aqueous solutions of formaldehyde and resorcinol in the presence of basic electrolytes such as sodium carbonate. It is well known that formaldehyde is present in the form of methylene glycols or methoxy-glycols in aqueous and methanolic solutions, but influence of pH or electrolytes on speciation in these solutions has not been previously studied. Here we investigated effects of sodium carbonate on the speciation and colloidal scale clustering in formaldehyde-methanol-water solutions in the absence of resorcinol. We used (13)C NMR spectroscopy to quantitatively characterize molecular speciation in solutions and to estimate corresponding equilibrium constants for glycol dimerization and methoxylation. We found that species distribution is essentially independent of carbonate concentration for pH values between 3.4 (no carbonate) and 10.6. This was also consistent with ATR IR measurements of the same solutions. However, NMR spin-spin relaxation time measurements showed an unexpected behavior for glycols and especially for diglycol (but not for methanol), with relaxation times strongly decreasing with increasing carbonate concentration, indicating differences in local molecular environment of glycols. We further used dynamic light scattering to confirm the presence of mesoscale clustering in formaldehyde-methanol-water (for both H2O and D2O) solutions in the presence of sodium carbonate. We propose that the observed phenomena are due to glycol-rich cluster mesospecies in equilibrium bulk solution, together forming a thermodynamically stable mesostructured liquid phase. PMID:23964642

Gaca, Katarzyna Z; Parkinson, John A; Sefcik, Jan

2013-09-12

205

Solution-processed flexible transparent conductors based on carbon nanotubes and silver grid hybrid films  

NASA Astrophysics Data System (ADS)

In a simple, cost-effective, and solution-based process, a thin-film of single-walled carbon nanotubes is hybridized on a PET film which has been patterned with solution self-assembled Ag nanoparticles. Such a flexible and transparent electrode exhibits a sheet resistance down to ~5.8 ? sq-1 at ~83.7% optical transmittance. The hybrid films are stable under ambient conditions and offer excellent bendability.In a simple, cost-effective, and solution-based process, a thin-film of single-walled carbon nanotubes is hybridized on a PET film which has been patterned with solution self-assembled Ag nanoparticles. Such a flexible and transparent electrode exhibits a sheet resistance down to ~5.8 ? sq-1 at ~83.7% optical transmittance. The hybrid films are stable under ambient conditions and offer excellent bendability. Electronic supplementary information (ESI) available: Experimental details, performance of graphene-Ag hybrid and met-SWNT-Ag hybrid films. See DOI: 10.1039/c3nr06386k

Wang, Jing; Zhang, Jintao; Sundramoorthy, Ashok Kumar; Chen, Peng; Chan-Park, Mary B.

2014-04-01

206

Adsorption of cadmium from aqueous solutions on sulfurized activated carbon prepared from nut shells.  

PubMed

Low-cost activated carbon, derived from nut shells, and its modified sample have been used as replacements for the current expensive methods of removing cadmium from aqueous solutions and waste waters. Adsorption of cadmium onto four kinds of activated carbons has been studied; prepared activated carbon (PAC), commercial activated carbon (CAC), and the sulfurized ones (SPAC & SCAC). The activated carbon has been derived, characterized, treated with sulfur and then utilized for the removal of Cd(2+). Sulfurizing agent (SO(2) gas) was successfully used in adsorbents' modification process at the ambient temperature. Samples were then characterized and tested as adsorbents of cadmium. Effect of some parameters such as contact time, initial concentration and pH were examined. With increasing pH, the adsorption of cadmium ions was increased and maximum removal, 92.4% for SPAC, was observed in pH>8.0 (C(0)=100mg/L). The H-type adsorption isotherms, obtained for the adsorbents, indicated a favorable process. Adsorption data on both prepared and commercial activated carbon, before and after sulfurization, followed both the Frendlich and Langmuir models. They were better fitted by Frendlich isotherm as compared to Langmuir. The maximum adsorption capacities were 90.09, 104.17, 126.58 and 142.86 mg/g for CAC, PAC, SCAC and SPAC, respectively. Accordingly, surface modification of activated carbons using SO(2) greatly enhanced cadmium removal. The reversibility of the process has been studied in a qualitative manner and it shows that the spent SPAC can be effectively regenerated for further use easily. PMID:19131159

Fouladi Tajar, Amir; Kaghazchi, Tahereh; Soleimani, Mansooreh

2009-06-15

207

Health Tip: Wash Hands for Food Safety  

MedlinePLUS

... National Library of Medicine National Institutes of Health Home About MedlinePlus Site Map FAQs Contact Us Search MedlinePlus ... Tip: Wash Hands for Food Safety When you should scrub up (*this news item ...

208

Wash water waste pretreatment system study  

NASA Technical Reports Server (NTRS)

The use of real wash water had no adverse effect on soap removal when an Olive Leaf soap based system was used; 96 percent of the soap was removed using ferric chloride. Numerous chemical agents were evaluated as antifoams for synthetic wash water. Wash water surfactants used included Olive Leaf Soap, Ivory Soap, Neutrogena and Neutrogena Rain Bath Gel, Alipal CO-436, Aerosol 18, Miranol JEM, Palmeto, and Aerosol MA-80. For each type of soapy wash water evaluated, at least one antifoam capable of causing nonpersistent foam was identified. In general, the silicones and the heavy metal ions (i.e., ferric, aluminum, etc.) were the most effective antifoams. Required dosage was in the range of 50 to 200 ppm.

1976-01-01

209

TRUCK WASHING TERMINAL WATER POLLUTION CONTROL  

EPA Science Inventory

A laboratory and pilot-scale investigation of a treatment sequence, including physical, chemical, and biological treatment steps led to a full-scale installation for the treatment of tank truck washing wastewater. The system included gravity separation, equalization, neutralizati...

210

Single Wall Carbon Nano Tube Films and Coatings  

Microsoft Academic Search

Purified single wall carbon nano tubes (SWNTs) produced from the high-pressure carbon monoxide (HiPCO) process have been dissolved \\/dispersed in oleum. These solutions \\/dispersions were optically homogeneous and have been used to form stand-alone SWNT films. The washed, dried, and heat-treated films are isotropic. The scanning electron micrographs of the film surface shows that the nanotube ropes (or fibrils) of

T. V. Sreekumar; Satish Kumar; Lars M. Ericson; Richard E. Smalley

2002-01-01

211

[Composite materials, carbon fiber-resin: a solution to the problem of aging of denture bases of removable prostheses].  

PubMed

The growing age of resin prosthesis is a worry for dentists, and chiefly for patients. Their reinforcement with carbon fiber appears to be a solution that frankly improves their life expectancy. PMID:11372136

N'Dindin, A C; N'Dindin, G B; Amani, S R; Morenas, M

2000-12-01

212

Chemical Behaviour of Pu and Am: Hydrolysis Reaction in Brine Solutions, Carbonate Complexation, alpha -Radiolysis, Humate Complexation and Speciation.  

National Technical Information Service (NTIS)

The chemical behaviour of transuranic elements (Pu and Am) has been investigated in saline solution of different NaCl concentrations in the near neutral pH range. Important reactions considered are hydrolysis, carbonate complexation, redox reaction, alpha...

J. I. Kim G. Buckau K. Bueppelmann R. Klenze C. Lierse

1986-01-01

213

Removal of mercury from aqueous solutions using activated carbon prepared from agricultural by-product/waste.  

PubMed

Removal of mercury from aqueous solutions using activated carbon prepared from Ceiba pentandra hulls, Phaseolus aureus hulls and Cicer arietinum waste was investigated. The influence of various parameters such as effect of pH, contact time, initial metal ion concentration and adsorbent dose for the removal of mercury was studied using a batch process. The experiments demonstrated that the adsorption process corresponds to the pseudo-second-order-kinetic models and the equilibrium adsorption data fit the Freundlich isotherm model well. The prepared adsorbents ACCPH, ACPAH and ACCAW had removal capacities of 25.88 mg/g, 23.66 mg/g and 22.88 mg/g, respectively, at an initial Hg(II) concentration of 40 mg/L. The order of Hg(II) removal capacities of these three adsorbents was ACCPH>ACPAH>ACCAW. The adsorption behavior of the activated carbon is explained on the basis of its chemical nature. The feasibility of regeneration of spent activated carbon adsorbents for recovery of Hg(II) and reuse of the adsorbent was determined using HCl solution. PMID:18313830

Rao, M Madhava; Reddy, D H K Kumar; Venkateswarlu, Padala; Seshaiah, K

2009-01-01

214

Effect of carbon on formation of mixed solid solutions during mechanochemical synthesis of Ni-Al-Mo-C mixtures and ordering of solutions during heating  

NASA Astrophysics Data System (ADS)

Solid solutions Ni(Al, Mo, C) are formed via milling the Ni2.8Al1Mo0.2 and Ni3Al0.8Mo0.2 and graphite-containing Ni2.8Al1Mo0.2C(0.25, 0.5) and Ni3Al0.8Mo0.2C(0.25, 0.5) mixtures. In this case, some amount of Mo remains beyond the solid solution. Graphite added to a starting mixture decreases the Mo solubility and favors the amorphization of solid solutions. The complete amorphization was found for the mixture with the 5 at % C and 5 at % Mo, which was added instead of Ni. The heating of mechanically synthesized (MS) powder alloys leads to the ordering of carbon-free and carbon-containing solid solutions with the formation of the L12 and E21 structure, respectively. In the course of the ordering of the Ni(Al, Mo, C) solid solutions, Mo and carbon precipitate in the form of the molybdenum carbide (Mo2C) second phase. The hardness of the MS three-phase Ni-Al-Mo-C solid solutions subjected to hot isostatic pressing is determined by the mass fraction of the formed Mo2C carbide. It is shown that the carbon content in the multicomponent antiperovskite can be estimated by analyzing the ratio of integral intensities of superlattice reflections I (100)/ I (110).

Portnoi, V. K.; Leonov, A. V.; Streletskii, A. N.; Logacheva, A. I.

2014-03-01

215

Development and distribution of bed-parallel compaction bands and pressure solution seams in carbonates (Bolognano Formation, Majella Mountain, Italy)  

NASA Astrophysics Data System (ADS)

The Oligo-Miocene ramp carbonates pertaining to the Bolognano Formation, cropping out at the Majella Mountain, Central Italy, are diffusely crosscut by bed-parallel structural elements such as compaction bands and pressure solution seams. These bed-parallel structural elements formed under a vertical loading, during the progressive burial of the carbonates. The present field and laboratory study focuses on the control exerted, on development and distribution of bed-parallel compaction bands and pressure solution seams, by compositional, sedimentological and pore network characteristics of a variety of carbonate rocks (skeletal grainstones and packstones, marly wackestones to mudstones). The main results are consistent with the following statements: (i) bed-parallel compaction bands formed only within poorly cemented, porous grainstones (2D porosity > 10%; 3D porosity > 15%). Their dimensional parameters (i.e., length, spacing, thickness) were strongly controlled by both sorting and sphericity of the carbonate grains, as well as by the amount of intergranular macroporosity. All these rock characteristics enhanced all physical processes (i.e. grain rotation, translation and fracturing) associated to compaction banding; (ii) bed-parallel pressure solution seams predominantly formed within fine-grained packstones made up of well-sorted and spherical carbonate grains with absence of internal pores, and small amounts of clayish matrix (2-4% of total rock volume). High contents of pre-existing cement also enhanced pressure solution; (iii) well-sorted carbonates with spherical grains may be suitable to both compaction banding and pressure solution; (iv) skeletal grain types which compose grain-supported carbonate rocks (grainstones and packstones), in many cases, indirectly influence the distribution of both bed-parallel compaction bands and pressure solution seams. Considering that the containment and migration capacity of geofluids in the subsurface within carbonate rocks is strongly influenced by the distribution of compaction bands and pressure solution seams, the results of this research provide new tools useful to improve the prediction of reservoir quality by mapping/simulating/assessing carbonate facies.

Rustichelli, A.; Tondi, E.; Agosta, F.; Cilona, A.; Giorgioni, M.

2012-04-01

216

Ultrasonic-assisted sodium hypochlorite oxidation of activated carbons for enhanced removal of Co(II) from aqueous solutions  

Microsoft Academic Search

Ultrasonic irradiation was employed to assist the modification of activated carbons (AC) by sodium hypochlorite, and tested for their ability to remove Co(II) from aqueous solutions. Modification of the activated carbon significantly enhanced their Co(II) adsorption capacity, which increased with the increasing NaOCl impregnating concentration. Ultrasonic-assisted impregnation can enhance the oxidation ability of the NaOCl solution, thus gave a higher

Weifeng Liu; Jian Zhang; Cheng Cheng; Guipeng Tian; Chenglu Zhang

2011-01-01

217

Adsorption of Direct Blue 53 dye from aqueous solutions by multi-walled carbon nanotubes and activated carbon.  

PubMed

Multi-walled carbon nanotubes (MWCNT) and powder activated carbon (PAC) were used as adsorbents for adsorption of Direct Blue 53 dye (DB-53) from aqueous solutions. The adsorbents were characterised using Raman spectroscopy, N2 adsorption/desorption isotherms, and scanning and transmission electron microscopy. The effects of initial pH, contact time and temperature on adsorption capacity of the adsorbents were investigated. At pH 2.0, optimum adsorption of the dye was achieved by both adsorbents. Equilibrium contact times of 3 and 4 h were achieved by MWCNT and PAC adsorbents, respectively. The general order kinetic model provided the best fit of the experimental data compared to pseudo-first order and pseudo-second order kinetic adsorption models. For DB-53 dye, the equilibrium data (298-323 K) were best fitted to the Sips isotherm model. The maximum sorption capacity for adsorption of the dye occurred at 323 K, with the values of 409.4 and 135.2 mg g(-1) for MWCNT and PAC, respectively. Studies of adsorption/desorption were conducted and the results showed that DB-53 loaded MWCNT could be regenerated (97.85%) using a mixture 50% acetone + 50% of 3 mol L(-1) NaOH. Simulated dye house effluents were used to evaluate the application of the adsorbents for effluent treatment (removal of 99.87% and 97.00% for MWCNT and PAC, respectively, were recorded). PMID:24076517

Prola, Lizie D T; Machado, Fernando M; Bergmann, Carlos P; de Souza, Felipe E; Gally, Caline R; Lima, Eder C; Adebayo, Matthew A; Dias, Silvio L P; Calvete, Tatiana

2013-11-30

218

Dissolution of Uranium(IV) Oxide in Solutions of Ammonium Carbonate and Hydrogen Peroxide  

SciTech Connect

Understanding the dissolution characteristics of uranium oxides is of fundamental scientific interest. Bench scale experiments were conducted to determine the optimal dissolution parameters of uranium(IV) oxide (UO2) powder in solutions of ammonium carbonate [(NH4)2CO3] and hydrogen peroxide (H2O2). Experimental parameters included variable peroxide and carbonate concentrations, and temperature. Results indicate the dissolution rate of UO2 in 1 M (NH4)2CO3 increases linearly with peroxide concentration ranging from 0.05 – 2 M (1:1 to 40:1 mol ratio H2O2:U), with no apparent maximum rate reached under the limited conditions used in our study. Temperature ranging studies show the dissolution rate of UO2 in 1 M (NH4)2CO3 and 0.1 M H2O2 (2:1 mol ratio H2O2:U) increases linearly from 15 °C to 60 °C, again with no apparent maximum rate reached. Dissolution of UO2 in solutions with constant [H2O2] and [(NH4)2CO3] ranging from 0.5 to 2 M showed no difference in rate; however dissolution was significantly reduced in 0.05 M (NH4)2CO3 solution. The results of this study demonstrate the influence of [H2O2], [(NH4)2CO3], and temperature on the dissolution of UO2 in peroxide-containing (NH4)2CO3 solutions. Future studies are planned to elucidate the solution and solid state complexes in these systems.

Smith, Steven C.; Peper, Shane M.; Douglas, Matthew; Ziegelgruber, Kate L.; Finn, Erin C.

2009-09-12

219

Thermodynamics of pentachlorophenol adsorption from aqueous solutions by oxidized multi-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

Chemical modification of MWCNTs via oxidation proved to be a useful tool to improve the suspension stability and solubility of MWCNTs in aqueous solution. Multi-walled carbon nanotubes (MWCNTs) were oxidized using different oxidizing agents and the produced oxidized MWCNTs were characterized using different techniques. IR measurements showed the presence of carboxylic acid function groups especially for the MWCNTs oxidized with nitric acid and hydrogen peroxide. Oxidation of MWCNTs increased their solubility in aqueous solution and hence enhances the contact between the carbon nanotubes and the water and pentachlorophenol molecules. The oxidized MWCNTs were used to study the removal of pentachlorophenol (PCP) from aqueous solutions. The equilibrium adsorption of PCP on the oxidized MWCNTs at various temperatures was studied and the adsorption equilibrium was well described using different adsorption models. The thermodynamic of adsorption was studied at different temperatures and the results showed that the adsorption process was product favored, and becomes more so at higher temperature, since the adsorption is endothermic in general.

Abdel Salam, M.; Burk, R. C.

2008-12-01

220

Computer simulation of cascade damage in ?-iron with carbon in solution  

NASA Astrophysics Data System (ADS)

Molecular dynamics simulation method is used to investigate defect production by displacement cascades in iron with carbon (C) in solution. This is the first study of cascade damage in a metal containing interstitial solute. Iron is of particular interest because of the use of ferritic steels in plant for nuclear power generation. Cascades are simulated with energy in the range 5-20 keV in iron at either 100 or 600 K containing carbon with concentration in the range 0-1 at.%. C in solution has no discernible effect on the number of defects produced in cascades under any of the conditions simulated, nor on the clustered fraction of either self-interstitial atoms (SIAs) or vacancies. However, significant fractions of single SIAs and vacancies are trapped by C in the cascade process, irrespective of cascade energy. The fraction is independent of temperature for vacancies, but increases strongly with temperature for SIAs: this is a consequence of the higher mobility of the SIA.

Calder, Andrew F.; Bacon, David J.; Barashev, Alexander V.; Osetsky, Yuri N.

2008-12-01

221

The removal of uranium (VI) from aqueous solutions onto activated carbon developed from grinded used tire.  

PubMed

In this study, activated carbon was prepared from waste tire by KOH chemical activation. The pore properties including the BET surface area, pore volume, pore size distribution, and average pore diameter were characterized. BET surface area of the activated carbon was determined as 558 m(2)/g. The adsorption of uranium ions from the aqueous solution using this activated carbon has been investigated. Various physico-chemical parameters such as pH, initial metal ion concentration, and adsorbent dosage level and equilibrium contact time were studied by a batch method. The optimum pH for adsorption was found to be 3. The removal efficiency has also been determined for the adsorption system as a function of initial concentration. The experimental results were fitted to Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherm models. A comparison of best-fitting was performed using the coefficient of correlation and the Langmuir isotherm was found to well represent the measured sorption data. According to the evaluation using the Langmuir equation, the saturated monolayer sorption capacity of uranium ions onto waste tire activated carbon was 158.73 mg/g. The thermodynamic equilibrium constant and the Gibbs free energy were determined and results indicated the spontaneous nature of the adsorption process. Kinetics data were best described by pseudo-second-order model. PMID:23821251

Belgacem, Ahmed; Rebiai, Rachid; Hadoun, Hocine; Khemaissia, Sihem; Belmedani, Mohamed

2014-01-01

222

Carbon enters silica forming a cristobalite-type CO2-SiO2 solid solution.  

PubMed

Extreme conditions permit unique materials to be synthesized and can significantly update our view of the periodic table. In the case of group IV elements, carbon was always considered to be distinct with respect to its heavier homologues in forming oxides. Here we report the synthesis of a crystalline CO2-SiO2 solid solution by reacting carbon dioxide and silica in a laser-heated diamond anvil cell (P=16-22?GPa, T>4,000?K), showing that carbon enters silica. Remarkably, this material is recovered to ambient conditions. X-ray diffraction shows that the crystal adopts a densely packed ?-cristobalite structure (P41212) with carbon and silicon in fourfold coordination to oxygen at pressures where silica normally adopts a sixfold coordinated rutile-type stishovite structure. An average formula of C0.6(1)Si0.4(1)O2 is consistent with X-ray diffraction and Raman spectroscopy results. These findings may modify our view on oxide chemistry, which is of great interest for materials science, as well as Earth and planetary sciences. PMID:24781844

Santoro, Mario; Gorelli, Federico A; Bini, Roberto; Salamat, Ashkan; Garbarino, Gaston; Levelut, Claire; Cambon, Olivier; Haines, Julien

2014-01-01

223

Carbon enters silica forming a cristobalite-type CO2–SiO2 solid solution  

NASA Astrophysics Data System (ADS)

Extreme conditions permit unique materials to be synthesized and can significantly update our view of the periodic table. In the case of group IV elements, carbon was always considered to be distinct with respect to its heavier homologues in forming oxides. Here we report the synthesis of a crystalline CO2–SiO2 solid solution by reacting carbon dioxide and silica in a laser-heated diamond anvil cell (P=16–22?GPa, T>4,000?K), showing that carbon enters silica. Remarkably, this material is recovered to ambient conditions. X-ray diffraction shows that the crystal adopts a densely packed ?-cristobalite structure (P41212) with carbon and silicon in fourfold coordination to oxygen at pressures where silica normally adopts a sixfold coordinated rutile-type stishovite structure. An average formula of C0.6(1)Si0.4(1)O2 is consistent with X-ray diffraction and Raman spectroscopy results. These findings may modify our view on oxide chemistry, which is of great interest for materials science, as well as Earth and planetary sciences.

Santoro, Mario; Gorelli, Federico A.; Bini, Roberto; Salamat, Ashkan; Garbarino, Gaston; Levelut, Claire; Cambon, Olivier; Haines, Julien

2014-04-01

224

Effect of yttrium and chromium ion implantation on crevice electrochemical behavior of carbon steel in sodium chloride solution  

Microsoft Academic Search

In order to study the effect of yttrium (Y) and chromium (Cr) ion implantation on the crevice corrosion behavior of carbon steel, the carbon steel was implanted with Y and Cr ion using MEVVA source at an energy of 40keV. Electrochemical measurement was employed to evaluate the crevice corrosion of implanted carbon steel in NaCl solution. The results indicated that,

Chenghao Liang; Naibao Huang

2008-01-01

225

Kinetics of the adsorption of polystyrene macromolecules from dilute solutions in methyl ethyl ketone on carbon black  

Microsoft Academic Search

The kinetics of the adsorption of a mixture of three polystyrenes (the weight-average molecular weight M\\u000a \\u000a w\\u000a = 8300, 34000, and 195000) on nonporous carbon (carbon black pretreated in the argon flow at 3800 K) from dilute solutions\\u000a in methyl ethyl ketone at 298 K is studied. The kinetic dependences of the adsorption of polystyrenes on carbon black nanoparticles\\u000a from

N. A. El’tekova; Yu. A. El’tekov

2007-01-01

226

Utilization of carbon nanotubes for the removal of rhodamine B dye from aqueous solutions.  

PubMed

Carbon nanotubes (CNTs) are attracting increasing research interest as promising adsorbents for harmful cations, anions, and other organic and inorganic impurities present in natural sources of water. This study examined the feasibility of removing Rhodamine B dye from aqueous solutions using multi walled carbon nanotubes (MWCNTs) synthesized by chemical vapor deposition (CVD) method. The effects of dye concentration, pH and contact time on adsorption of direct dye by CNTs were also evaluated. The study used the Langmuir and Temkin isotherms to describe equilibrium adsorption. Additionally, pseudo second-order model was adopted to evaluate experimental data and thereby elucidate the kinetic adsorption process. The adsorption percentage of dye increased as contact time increased. Conversely, the adsorption percentage of dye decreased as dye concentration increased. The pseudo second-order model best represented adsorption kinetics. The capacity of CNTs to adsorb Rhodamine B was 65-90% at different pH values. PMID:24738392

Kumar, Sandeep; Bhanjana, Gaurav; Jangra, Kavita; Dilbaghi, Neeraj; Umar, Ahmad

2014-06-01

227

Dehydration and crystallization of amorphous calcium carbonate in solution and in air  

PubMed Central

The mechanisms by which amorphous intermediates transform into crystalline materials are poorly understood. Currently, attracting enormous interest is the crystallization of amorphous calcium carbonate, a key intermediary in synthetic, biological and environmental systems. Here we attempt to unify many contrasting and apparently contradictory studies by investigating this process in detail. We show that amorphous calcium carbonate can dehydrate before crystallizing, both in solution and in air, while thermal analyses and solid-state nuclear magnetic resonance measurements reveal that its water is present in distinct environments. Loss of the final water fraction—comprising less than 15% of the total—then triggers crystallization. The high activation energy of this step suggests that it occurs by partial dissolution/recrystallization, mediated by surface water, and the majority of the particle then crystallizes by a solid-state transformation. Such mechanisms are likely to be widespread in solid-state reactions and their characterization will facilitate greater control over these processes.

Ihli, Johannes; Wong, Wai Ching; Noel, Elizabeth H.; Kim, Yi-Yeoun; Kulak, Alexander N.; Christenson, Hugo K.; Duer, Melinda J.; Meldrum, Fiona C.

2014-01-01

228

Lithologic Controls on the Development of Solution Porosity in Carbonate Aquifers  

NASA Astrophysics Data System (ADS)

Movement of ground water in maturely karsted limestone aquifers is commonly through solution conduits of considerable size. The object of this study was to determine the lithologic controls on the distribution of conduits within a heterogeneous sequence of carbonate rocks. The volume of all accessible caves more than 100 feet in length in the Nittany Valley area of central Pennsylvania was measured. Most caves are entirely within limestones, cave development in dolomite is extremely rare. Within the limestone sequence the bulk of the cave volume is concentrated in a few members. Chemical and petrographic analyses of the carbonate rocks were associated with cave volume by bar graphs and components analyses. The more cavernous limestones seem to be those with low amounts of dolomite, clay, and other impurities, and a high micrite grain fraction. Coarse limestones and dolomites are less cavernous.

Rauch, Henry W.; White, William B.

1970-08-01

229

Dehydration and crystallization of amorphous calcium carbonate in solution and in air.  

PubMed

The mechanisms by which amorphous intermediates transform into crystalline materials are poorly understood. Currently, attracting enormous interest is the crystallization of amorphous calcium carbonate, a key intermediary in synthetic, biological and environmental systems. Here we attempt to unify many contrasting and apparently contradictory studies by investigating this process in detail. We show that amorphous calcium carbonate can dehydrate before crystallizing, both in solution and in air, while thermal analyses and solid-state nuclear magnetic resonance measurements reveal that its water is present in distinct environments. Loss of the final water fraction--comprising less than 15% of the total--then triggers crystallization. The high activation energy of this step suggests that it occurs by partial dissolution/recrystallization, mediated by surface water, and the majority of the particle then crystallizes by a solid-state transformation. Such mechanisms are likely to be widespread in solid-state reactions and their characterization will facilitate greater control over these processes. PMID:24469266

Ihli, Johannes; Wong, Wai Ching; Noel, Elizabeth H; Kim, Yi-Yeoun; Kulak, Alexander N; Christenson, Hugo K; Duer, Melinda J; Meldrum, Fiona C

2014-01-01

230

Evaluation of some bipyridinium dihalides as inhibitors for low carbon steel corrosion in sulfuric acid solution  

Microsoft Academic Search

Inhibition of low carbon steel (LCS) corrosion in 0.5 M H2SO4 solution by three bipyridinium dihalides (TMbPyBr2, HMbPyBr2 and MPhbPyCl2) was evaluated by potentiodynamic polarization curves, EIS and SEM techniques. The effectiveness of the inhibitors is ranked\\u000a as follows: MPhbPyCl2 ? TMbPyBr2 > HMbPyBr2. The compounds behave as mixed-type inhibitors and their adsorption on the steel surface obeys the Langmuir adsorption isotherm.\\u000a EIS measurements indicate

M. S. Morad; A. A. Hermas; A. Y. Obaid; A. H. Qusti

2008-01-01

231

Laboratory differential simulation design method of pressure absorbers for carbonization of phenolate solution by carbon dioxide in coal-tar processing  

SciTech Connect

A laboratory differential simulation method is used for the design of carbonization columns at coal-tar processing in which phenols are regenerated from phenolate solution by carbon dioxide absorption. The design method is based on integration of local absorption rates of carbon dioxide along the column. The local absorption rates into industrial phenolate mixture are measured in a laboratory model contactor for various compositions of the gas and liquid phases under the conditions that ensure the absorption rates in the laboratory absorber simulate the local rates in the industrial column. On the bases of the calculations, two-step carbonization columns were designed for 30000 t/year of the phenolate solution treatment by carbon dioxide. The absorption proceeds at higher pressure of 500 kPa and temperatures from 50 to 65 C, pure carbon dioxide is used and toluene is added. These conditions have the following favourable effects: (I) significant size reduction of the columns, (ii) it is possible to process more concentrated solutions without danger of silting the columns by crystallization of NaHCO{sub 3} on the packing. (iii) small amount of inert gas is released, (iv) lower alkalinity and better separability of the organic phase (phenols with toluene) from water phase (soda or bicarbonate solution) in separators.

Linek, V.; Sinkule, J.; Moucha, T.; Rejl, J.F. [Prague Institute for Chemical Technology, Prague (Czech Republic). Dept. of Chemical Engineering

2009-01-15

232

Separation of hydrophobic organic compound from surfactant solutions with activated carbon in a fixed bed.  

PubMed

The adsorption behavior of phenanthrene (PHE) in Triton X-100 (TX100) solutions with fixed activated carbon (AC) bed was studied to recover the surfactant. The effect of various parameters like bed depths, flow rates, influent TX100 concentration, and influent PHE concentration were investigated. The breakthrough time of both TX100 and PHE increased with the increase of bed height and decrease of flow rate and influent concentration. In the case of fixed length, a lower flow rate, higher concentration of TX100, and lower concentration of PHE will benefit the longer effective surfactant recovery time. The adsorption data were integrated into bed depth service time models. The height of exchange zone of TX100 should be much shorter than that of PHE, which provides conditions to separate the hydrophobic organic compound from surfactant solutions with AC in a fixed bed. It is likely that the adsorption process is controlled by hydrophobic interaction. PMID:24292481

Liu, Jianfei; Chen, Jiajun; Jiang, Lin; Chen, Cheng

2013-01-01

233

Activity of Cu-activated carbon fiber catalyst in wet oxidation of ammonia solution.  

PubMed

Aqueous solutions of 200-1000 mg/L of ammonia were oxidized in a trickle-bed reactor using Cu-activated carbon fiber (ACF) catalysts, which were prepared by incipient wet impregnation with aqueous solutions of copper nitrate that was deposited on ACF substrates. The results reveal that the conversion of ammonia by wet oxidation in the presence of Cu-ACF catalysts was a function of the metal loading weight ratio of the catalyst. The total conversion efficiency of ammonia was 95% during wet oxidation over the catalyst at 463 K at an oxygen partial pressure of 3.0 MPa. Moreover, the effect of the initial concentration of ammonia and the reaction temperature on the removal of ammonia from the effluent streams was also studied at a liquid space velocity of less than 3.0 h(-1). PMID:19147285

Hung, Chang-Mao

2009-07-30

234

Synthesis of finely divided molybdenum sulfide nanoparticles in propylene carbonate solution  

NASA Astrophysics Data System (ADS)

Molybdenum sulfide nanoparticles have been prepared from the reflux solution reaction involving ammonium heptamolybdate and elemental sulfur in propylene carbonate. Addition to the reaction mixture of starch as a natural capping agent leads to lesser agglomeration and smaller size of the particles. Nanoparticles of MoSx (x?4) of 10-30 nm size are highly divided and form stable colloidal suspensions in organic solvents. Mo K edge EXAFS of the amorphous materials shows rapid exchange of oxygen to sulfur in the molybdenum coordination sphere during the solution reaction. Thermal treatment of the amorphous sulfides MoSx under nitrogen or hydrogen flow at 400 °C allows obtaining mesoporous MoS2 materials with very high pore volume and specific surface area, up to 0.45 cm3/g and 190 m2/g, respectively. The new materials show good potential for the application as unsupported hydrotreating catalysts.

Afanasiev, Pavel

2014-05-01

235

Corrosion Inhibition of Carbon Steel by New Thiophene Azo Dye Derivatives in Acidic Solution  

NASA Astrophysics Data System (ADS)

Inhibition of carbon steel corrosion in 2 M hydrochloric acid (HCl) solution by thiophene azo dye derivatives were studied using weight loss, electrochemical frequency modulation (EFM), and atomic absorption techniques. The experimental data suggest that the inhibition efficiency increases with increasing inhibitors concentration in presence of 103 ?M potassium iodide (KI). This is due to synergistic effect. Thus, the experimental results suggested that the presence of these anions in the solution stabilized the adsorption of inhibitors molecules on the metal surface and improved the inhibition efficiency. The results of EFM experiments are a spectrum of current response as a function of frequency. The corrosion rate and Tafel parameters can be obtained with measurement by analyzing the harmonic frequencies. The adsorption of the inhibitors on metal surface obeys the Langmuir adsorption isotherm. The surface of metal examined using Fourier transform infrared and ultraviolet spectroscopy. Quantum chemical calculations were carried out and relations between computed parameters and experimental inhibition efficiency were discussed.

El-Haddad, Mahmoud N.; Fouda, A. S.; Mostafa, H. A.

2013-08-01

236

Carbonation and Other Super Saturated Gases as Solution Modifiers for Improved Sensitivity in Solvent Assisted Ionization Inlet (SAII) and ESI  

NASA Astrophysics Data System (ADS)

Solvent Assisted Ionization Inlet (SAII) produces ions in a heated inlet to a mass spectrometer from aqueous and aqueous/organic solutions with high sensitivity. However, the use of acid modifiers, which typically aids electrospray ionization, generally results in ion suppression in SAII. Here we demonstrate that the use of carbonation and other super-saturated gases as solution modifiers increases analyte ion abundance and reduces metal cation adduction in SAII. Carbonation is also found to enhance electrospray ionization. The mechanistic and practical utility of carbonation in mass spectrometry is addressed.

Pagnotti, Vincent S.; Chakrabarty, Shubhashis; McEwen, Charles N.

2013-02-01

237

Carbonation and other super saturated gases as solution modifiers for improved sensitivity in solvent assisted ionization inlet (SAII) and ESI.  

PubMed

Solvent Assisted Ionization Inlet (SAII) produces ions in a heated inlet to a mass spectrometer from aqueous and aqueous/organic solutions with high sensitivity. However, the use of acid modifiers, which typically aids electrospray ionization, generally results in ion suppression in SAII. Here we demonstrate that the use of carbonation and other super-saturated gases as solution modifiers increases analyte ion abundance and reduces metal cation adduction in SAII. Carbonation is also found to enhance electrospray ionization. The mechanistic and practical utility of carbonation in mass spectrometry is addressed. PMID:23296909

Pagnotti, Vincent S; Chakrabarty, Shubhashis; McEwen, Charles N

2013-02-01

238

Washing of waste prior to landfilling.  

PubMed

The main impact produced by landfills is represented by the release of leachate emissions. Waste washing treatment has been investigated to evaluate its efficiency in reducing the waste leaching fraction prior to landfilling. The results of laboratory-scale washing tests applied to several significant residues from integrated management of solid waste are presented in this study, specifically: non-recyclable plastics from source separation, mechanical-biological treated municipal solid waste and a special waste, automotive shredded residues. Results obtained demonstrate that washing treatment contributes towards combating the environmental impacts of raw wastes. Accordingly, a leachate production model was applied, leading to the consideration that the concentrations of chemical oxygen demand (COD) and total Kjeldahl nitrogen (TKN), parameters of fundamental importance in the characterization of landfill leachate, from a landfill containing washed wastes, are comparable to those that would only be reached between 90 and 220years later in the presence of raw wastes. The findings obtained demonstrated that washing of waste may represent an effective means of reducing the leachable fraction resulting in a consequent decrease in landfill emissions. Further studies on pilot scale are needed to assess the potential for full-scale application of this treatment. PMID:22245736

Cossu, Raffaello; Lai, Tiziana

2012-05-01

239

Technical bases DWPF Late Washing Facility  

SciTech Connect

A task force recommended that the technical feasibility of a Late Wash' facility be assessed [1]. In this facility, each batch of tetraphenylborate slurry from Tank 49 would be given a final wash to reduce the concentrations of nitrite and radiolysis products to acceptable levels. Laboratory-scale studies have demonstrated that d the nitrite content of the slurry fed to DWPF is reduced to 0.01 M or less (and at least a 4X reduction in concentration of the soluble species is attained), (1) the need for HAN during hydrolysis is eliminated (eliminating the production of ammonium ion during hydrolysis), (2) hydrolysis may be done with a catalyst concentration that will not exceed the copper solubility in glass and (3) the non-polar organic production during hydrolysis is significantly reduced. The first phase of an aggressive research and development program has been completed and all test results obtained to date support the technical feasibility of Late Washing. Paralleling this research and development effort is an aggressive design study directed by DWPF to scope and cost retrofitting the Auxiliary Pump Pit (APP) to enable performing a final wash of each batch of precipitate slurry before R is transferred into the DWPF Soft Processing Cell (SPC). An initial technical bases for the Late Wash Facility was transmitted to DWPF on June 15, 1992. Research and development activities are continuing directed principally at optimization of the cross-f low fitter decontamination methodology and pilot-scale validation of the recommended benzene stripping metodology.

Fish, D.L.; Landon, L.F.

1992-08-10

240

Removal of malachite green dye from aqueous solution using rambutan peel-based activated carbon: Equilibrium, kinetic and thermodynamic studies  

Microsoft Academic Search

The adsorption of malachite green (MG) dye onto rambutan peel-based activated carbon (RPAC) was carried out in this work. The effects of different reaction parameters such as the initial MG concentration, contact time, solution temperature and initial pH on MG adsorption were investigated. MG adsorption uptake was found to increase with increase in initial concentration, contact time and solution temperature.

Mohd Azmier Ahmad; Rasyidah Alrozi

2011-01-01

241

Adsorptive removal of aniline by granular activated carbon from aqueous solutions with catechol and resorcinol.  

PubMed

In the present paper, the removal of aniline by adsorption process onto granular activated carbon (GAC) is reported from aqueous solutions containing catechol and resorcinol separately. The Taguchi experimental design was applied to study the effect of such parameters as the initial component concentrations (C(0,i)) of two solutes (aniline and catechol or aniline and resorcinol) in the solution, temperature (T), adsorbent dosage (m) and contact time (t). The L27 orthogonal array consisting of five parameters each with three levels was used to determine the total amount of solutes adsorbed on GAC (q(tot), mmol/g) and the signal-to-noise ratio. The analysis of variance (ANOVA) was used to determine the optimum conditions. Under these conditions, the ANOVA shows that m is the most important parameter in the adsorption process. The most favourable levels of process parameters were T = 303 K, m = 10 g/l and t = 660 min for both the systems, qtot values in the confirmation experiments carried out at optimum conditions were 0.73 and 0.95 mmol/g for aniline-catechol and aniline-resorcinol systems, respectively. PMID:22720400

Suresh, S; Srivastava, V C; Mishrab, I M

2012-01-01

242

Active and passive behavior of sintered iron in ammoniacal ammonium carbonate solution  

NASA Astrophysics Data System (ADS)

The anodic dissolution behavior of sintered iron in ammoniacal ammonium carbonate solution (pH = 9.7) has been investigated with the aid of electrochemical techniques. Surface films formed on bulk iron during air exposure or immersion in the ammoniacal solution were characterized by using X-ray photoelectron spectroscopy (XPS). Immersion in the ammoniacal solution gave an apparent open circuit potential (OCP) in the range of E = 0.04 to 0.09 V, standard hydrogen electrode (SHE); at these potentials, no dissolution of Fe was detected. Potential transients obtained during cathodic reactivation and the XPS results suggest that an air-formed oxide of Fe3O4 is responsible for this behavior. The anodic polarization behavior of sintered Fe was similar to that of bulk Fe, showing active, passive, and oxygen evolution regions. A very high current density observed in the passive region for some sintered specimens was attributable to active dissolution within the pore structure, analogous to conditions during crevice corrosion. The presence of oxygen in the solution stabilized both the passive film and the more noble apparent OCP.

Kim, H. S.; Kho, Y. T.; Osseo-Asare, K.; Pickering, H. W.

1991-06-01

243

Electrochemical behavior of A516 carbon steel in solutions containing hydrogen sulfide  

SciTech Connect

The electrochemical behavior of A516 grade 70 (UNS K02700) carbon steel with a ferrite-pearlite structure in acidic chloride (Cl{sup {minus}}) solutions containing hydrogen sulfide at 25 C was investigated by electrochemical impedance spectroscopy (EIS). Results showed the impedance of A516 steel increased in an acidic Cl{sup {minus}} solution with H{sub 2}S (compared to a solution without H{sub 2}S) at the open-circuit potential (OCP). The corrosion process for A516 steel in the H{sub 2}S-containing solution was in two stages. Polarization resistance initially increased with time for immersion up to {approximately} 10 h but then decreased gradually. In the early stage, the impedance was characterized by one large semicircle in the Nyquist plot that increased with time for immersion up to 3 h. In the later stage, precipitation of a sulfide film modified the surface properties and led to variation in EIS data through a capacitive effect in the low-frequency region.

Huang, H.H.; Tsai, W.T.; Lee, J.T. [National Cheng Kung Univ., Tainan (Taiwan, Province of China). Dept. of Materials Science and Engineering

1996-09-01

244

Wash solvent reuse in paint production  

SciTech Connect

The project evaluated solvent used to clean paint manufacture equipment for its utility in production of subsequent batches of solvent-borne paint. Reusing wash solvent would reduce the amount of solvent disposed of as waste. The evaluation of this wash-solvent recovery technology was conducted by Battelle Memorial Institute for the Pollution Prevention Research Branch of the U.S. Environmental Protection Agency. The evaluation was conducted with the cooperation and assistance of Vanex Color, Inc. The product quality, waste reduction/pollution prevention, and economic impacts of this technology change, as it has been implemented by Vanex, were examined. Two batches of a solvent-borne alkyd house paint were prepared at Vanex--one batch made with 100%-new solvent and the other with 30%-wash solvent--and sampled for laboratory analysis at Battelle.

Parsons, A.B.; Heater, K.J.; Olfenbuttel, R.F.

1994-04-01

245

Wash water reclamation technology for advanced manned spacecraft  

NASA Technical Reports Server (NTRS)

The results of an analytical study and assessment of state-of-the-art wash water reclamation technology for advanced manned spacecraft is presented. All non-phase-change unit operations, unit processes, and subsystems currently under development by NASA are considered. Included among these are: filtration, ultrafiltration, carbon adsorption, ion exchange, chemical pretreatment, reverse osmosis, hyperfiltration, and certain urea removal techniques. Performance data are given together with the projected weights and sizes of key components and subsystems. In the final assessment, a simple multifiltration approach consisting of surface-type cartridge filters, carbon adsorption and ion exchange resins receives the highest rating for six-man orbital missions of up to 10 years in duration.

Putnam, D. F.

1977-01-01

246

Adsorption of p-nitroaniline from aqueous solutions onto activated carbon fiber prepared from cotton stalk.  

PubMed

Activated carbon fiber prepared from cotton stalk was used as an adsorbent for the removal of p-nitroaniline (PNA) from aqueous solutions. Liquid phase adsorption experiments were conducted and the maximum adsorptive capacity was determined. The effect of experimental parameters such as pH, salinity and temperature on the adsorption was studied. The obtained experimental data were then fitted with the Langmuir, Freundlich and Redlich-Peterson models to describe the equilibrium isotherms. The kinetics rates were modeled by using the pseudo-first-order and pseudo-second-order equations. The results indicated that cotton stalk activated carbon fiber (CS-ACF) is an effective adsorbent for the removal of PNA from aqueous solutions. The maximum adsorption capacity of 406 mg g(-1) was achieved at the initial PNA concentration of 200 mg L(-1). The optimum pH for the removal of PNA was found to be 7.6. The presence of ammonium chloride proved to be favorable for the process of adsorption. The adsorption amount decreased with increasing temperature. The Redlich-Peterson model was found to best represent the equilibrium data. The kinetic data followed closely the pseudo-second-order equation. Thermodynamic study showed the adsorption was a spontaneous exothermic physical process. PMID:19157698

Li, Kunquan; Zheng, Zheng; Feng, Jingwei; Zhang, Jibiao; Luo, Xingzhang; Zhao, Guohua; Huang, Xingfa

2009-07-30

247

Dissolved organic carbon in soil solution of peat-moorsh soils on Kuwasy Mire  

NASA Astrophysics Data System (ADS)

Key words: peat-moorsh soils, soil solution, dissolved organic carbon (DOC), temperature of soil, redox potential. The objective this study was the dissolved organic carbon concentration (DOC) in soil solution on the background of soil temperature, moisture and redox potential. The investigations were localized on the area of drained and agricultural used Kuwasy Mire, which are situated in the middle basin of Biebrza River, in North-East Poland. Research point was placed on a low peat soil of 110 cm depth managed as extensive grassland. The soil was recognized as peat-moorsh with the second degree of the moorshing process (with 20 cm of moorsh layer). The ceramic suction cups were installed in three replications at 30 cm depth of soil profile. The soil solution was continuously sampled by pomp of the automatic field station. The successive samples comprised of solution collected at the intervals of 21 days. Simultaneously, at the 20, 30 and 40 cm soil depths the measurements of temperature and determination of soil moisture and redox potential were made automatically. The mean twenty-four hours data were collected. The concentrations of DOC were determined by means of the flow colorimeter using the Skalar standard methods. Presented observations were made in 2001-2006. Mean DOC concentration in soil solution was 66 mg.dm-3 within all research period. A significant positive correlation between studied compound concentration and temperature of soil at 30 cm depth was observed; (correlation coefficient - r=0.55, number of samples - n=87). The highest DOC concentrations were observed during the season from July to October, when also a lower ground water level occurred. The DOC concentration in soil solution showed as well a significant correlation with the soil redox potential at 20 cm level. On this depth of describing soil profile a frontier layer between moorshing layer and peat has been existed. This layer is the potentially most active in the respect to biochemical transformation. On the other hand it wasn't possible to shown dependences on the DOC concentration from soil moisture. That probably results from a huge water-holding capacity of these type of peat soils, which are keeping a high moisture content even at a long time after decreasing of the groundwater table.

Jaszczy?ski, J.; Sapek, A.

2009-04-01

248

A descriptive model for metallic ions adsorption from aqueous solutions onto activated carbons.  

PubMed

The design of adsorber units is mainly dependent on the equilibrium adsorption capacity of the sorbent in the working conditions. At the moment, these data are available in a limited number of experimental conditions and, for the case of activated carbon, there are no predictive models to assess the adsorption capacity as a function of the process parameters. This makes the adsorber design a complex and approximated task. In this work, a model for the description of metallic ions adsorption onto activated carbon is presented. The model starts from an evaluation of ion speciation and it considers the approach of the multi-component Langmuir model to correlate the metal uptake to the ion concentration in solution. The model has been used to analyse available experimental data on the adsorption of As(V), Cd(II), Cr(III) and Cr(VI) ions on activated carbon. A good matching between experimental results and model predictions has been obtained for all the investigated conditions. PMID:19411134

Di Natale, F; Erto, A; Lancia, A; Musmarra, D

2009-09-30

249

Adsorption equilibrium, kinetics and thermodynamics of dichloroacetic acid from aqueous solution using mesoporous carbon.  

PubMed

The presence of disinfection by-products, such as trihalomethanes and haloacetic acids in water, is believed to be harmful to human health. In this work, mesoporous carbon was synthesized with the evaporation-induced self-assembly method and employed to evaluate the effects of initial concentration, contact time, pH and temperature on the removal of dichloroacetic acid in batch experiments. Adsorption equilibrium was established in 480 min and the maximum adsorption (350mg/g) of dichloroacetic acid on the mesoporous carbon was observed to occur at 308 K and pH 3.0. Freundlich and Langmuir isotherms were used to analyse the equilibrium data at different temperatures; kinetic data were fitted to the pseudo-first-order and pseudo-second-order models and found that the adsorption capacity, mass transfer coefficient and diffusivity of dichloroacetic acid were directly affected by the physical and chemical parameters. In addition, the various thermodynamic parameters, such as Gibbs free energy (Delta G), enthalpy (Delta H = 54.35 kJmol-1) and entropy (Delta S = 258.36 Jmol-1 K-1) were calculated to analyse the adsorption process. The experimental results indicated that the mesoporous carbon was an excellent adsorbent for dichloroacetic acid removal from aqueous solutions. PMID:24956790

Ding, Ying; Zhu, Jianzhong; Cao, Yang; Chen, Shenglu

2014-08-01

250

Corrosion behavior of titanium alloy Beta-21S coated with diamond like carbon in Hank's solution  

NASA Astrophysics Data System (ADS)

Diamond like carbon (DLC) coatings posses high hardness and low friction coefficient and also biocompatible, hence, they are of interest for enhancing the wear and corrosion resistance of bio-implant materials. Beta stabilized titanium alloys are attractive for biomedical applications because of their high specific strength and low modulus. In this work Beta-21S alloy (Ti-15Mo-3Nb-3Al-0.2Si) was implanted with carbon ions by plasma immersion ion implantation using methane and hydrogen gas mixture followed by DLC deposition by plasma enhanced chemical vapour deposition (PECVD). The implanted layers enabled deposition of adherent diamond-like carbon coatings on the titanium alloy which was otherwise not possible. The corrosion behavior of the treated and untreated samples was investigated through electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization studies in simulated body fluid (Hank's solution). XPS, micro Raman and EDAX investigation of the samples showed the formation of a thin oxide layer on the treated samples after corrosion experiments. Corrosion resistance of the DLC coated sample is comparable with that of the untreated samples. Electrochemical impedance data of the substrate and implanted samples were fitted with two time constant equivalent circuits and that of DLC coated samples with two-layer model.

Mohan, L.; Anandan, C.; Grips, V. K. William

2012-06-01

251

Electrochemical behavior of glassy carbon electrodes modified by multi-walled carbon nanotube\\/surfactant films in a buffer solution and an ionic liquid  

Microsoft Academic Search

The electrochemical behavior of glassy carbon (GC) electrodes coated with multi-walled carbon nanotube (MWCNT)\\/surfactant films was studied in an ionic liquid and a phosphate buffer solution (pH=6.86), using cyclic voltammetry. The dispersion of MWCNTs in different media was investigated by scanning and transmission electron microscopy. Cast films of MWCNT\\/zwitterionic dodecyldimethylamine oxide on a GC electrode show a typical redox couple

Yi Li; Xingwang Shi; Jingcheng Hao

2006-01-01

252

Domestic wash water reclamation for reuse as commode water supply using filtration: Reverse-osmosis separation technique  

NASA Technical Reports Server (NTRS)

A combined filtration-reverse-osmosis water recovery system has been evaluated to determine its capability to reclaim domestic wash water for reuse as a commode water supply. The system produced water that met all chemical and physical requirements established by the U.S. Public Health Service for drinking water with the exception of carbon chloroform extractables, methylene blue active substances, and phenols. It is thought that this water is of sufficient quality to be reused as commode supply water. The feasibility of using a combined filtration and reverse-osmosis technique for reclaiming domestic wash water has been established. The use of such a technique for wash-water recovery will require a maintenance filter to remove solid materials including those less than 1 micron in size from the wash water. The reverse-osmosis module, if sufficiently protected from plugging, is an attractive low-energy technique for removing contaminants from domestic wash water.

Hall, J. B., Jr.; Batten, C. E.; Wilkins, J. R.

1974-01-01

253

RADIOACTIVE TRACER TECHNIQUES FOR DETECTING AND MEASUREING DETERGENT RESIDUE ON WASHED FOODS AND EVALUATION OF FOOD WASHING PRACTICES. Progress Report  

Microsoft Academic Search

Commercial food washing procedures were evaluated to determine the ; effect of variations in washing conditfons on the final cleanliness of the washed ; foods. Asparagus was selected as the test food. The extent of removal of ; bacterial spores measured the effectiveness of the washing conditions in removal ; of natural contaminants. Alkyl benzene suifate, labeled with S³⁵, was

1960-01-01

254

Covalent cum noncovalent functionalizations of carbon nanotubes for effective reinforcement of a solution cast composite film.  

PubMed

Although carbon nanotubes have impressive tensile properties, exploiting these properties in composites, especially those made by the common solution casting technique, seems to be elusive thus far. The reasons could be partly due to the poor nanotube dispersion and the weak nanotube/matrix interface. To solve this dual pronged problem, we combine noncovalent and covalent functionalizations of nanotubes in a single system by the design and application of a novel dispersant, hydroxyl polyimide-graft-bisphenol A diglyceryl acrylate (PI(OH)-BDA), and use them with epoxidized single-walled carbon nanotubes (O-SWNTs). Our novel PI(OH)-BDA dispersant functionalizes the nanotubes noncovalently to achieve good dispersion of the nanotubes because of the strong ?-? interaction due to main chain and steric hindrance of the BDA side chain. PI(OH)-BDA also functionalizes O-SWNTs covalently because it reacts with epoxide groups on the nanotubes, as well as the cyanate ester (CE) matrix used. The resulting solution-cast CE composites show 57%, 71%, and 124% increases in Young's modulus, tensile strength, and toughness over neat CE. These values are higher than those of composites reinforced with pristine SWNTs, epoxidized SWNTs, and pristine SWNTs dispersed with PI(OH)-BDA. The modulus and strength increase per unit nanotube weight fraction, i.e., dE/dW(NT) and d?/dW(NT), are 175 GPa and 7220 MPa, respectively, which are significantly higher than those of other nanotube/thermosetting composites (22-70 GPa and 140-3540 MPa, respectively). Our study indicates that covalent cum noncovalent functionalization of nanotubes is an effective tool for improving both the nanotube dispersion and nanotube/matrix interfacial interaction, resulting in significantly improved mechanical reinforcement of the solution-cast composites. PMID:22432973

Yuan, Wei; Chan-Park, Mary B

2012-04-01

255

The effect of washing water on bonding to etched enamel.  

PubMed

There is current concern about bacterial contamination of dental unit waterlines. This research hypothesized that the presence of increasing concentrations of bacteria in water used to wash etched enamel would result in a corresponding decrease in both shear bond strength (SBS) and critical surface tension (gammaC) of enamel. A further hypothesis was made that there is a correlation between SBS and gammaC. The effect of 3.5 ppm iodine in the water as a bacteriostatic agent was also assessed. Five groups of 10 samples of bovine enamel were etched, washed, and a resin composite bonded to them. The control group was washed with distilled water. Another group was washed with the dilute iodine solution. The remaining three groups used a different concentration of Escherichia coli DH5alpha as follows (in cfu mL(-1)): group 1: 10(2); group 2: 10(4); group 3: 10(6). Shear bond strength data were measured on an Instron testing machine at a crosshead speed of 1 mm min(-1). Adhesion data were (MPa): control: 24.6 +/- 6.0; with iodine: 20.8 +/- 2.7; group 1: 19.8 +/- 2.7; group 2: 13.5 +/- 3.0; group 3: 13.9 +/- 3.6. The F-test yielded a highly significant difference between control group, iodine group and group 1, compared with groups 2 and 3 (P < 0.0001). Tukey's Studentized Range Test was used for pairwise comparison testing between groups. Using a Cahn dynamic contact angle analyzer and linear regression analysis, the plots of surface tension versus costheta were extrapolated to costheta = 1 to give gammaC data for the control group and groups 1-3. In all cases reasonable linearity was observed (r2 > or = 0.87). Data (mN m(-1)) were: control group: 50.8; group 1: 45.1; group 2: 43.2; group 3: 39.5. The SBS and gammaC were then plotted against each other and linear regression analysis performed. It was concluded that increasing concentrations of bacteria in wash water decreased both SBS and gammaC and that a linear correlation (R2 = 0.84) was found between the values of these two parameters. PMID:15125603

Schneider, D J; Combe, E C; Martens, L V

2004-01-01

256

Adsorption of tetracycline from aqueous solutions onto multi-walled carbon nanotubes with different oxygen contents  

PubMed Central

Oxidized multi-walled carbon nanotubes (MWCNTs) with different oxygen contents were investigated for the adsorption of tetracycline (TC) from aqueous solutions. As the surface oxygen content of the MWCNTs increased, the maximum adsorption capacity and adsorption coefficient of TC increased to the largest values and then decreased. The relation can be attributed to the interplay between the nanotubes' dispersibility and the water cluster formation upon TC adsorption. The overall adsorption kinetics of TC onto CNTs-3.2%O might be dependent on both intra-particle diffusion and boundary layer diffusion. The maximum adsorption capacity of TC on CNTs-3.2%O was achieved in the pH range of 3.3–8.0 due to formation of water clusters or H-bonds. Furthermore, the presence of Cu2+ could significantly enhanced TC adsorption at pH of 5.0. However, the solution ionic strength did not exhibit remarkable effect on TC adsorption. In addition, when pH is beyond the range (3.3–8.0), the electrostatic interactions caused the decrease of TC adsorption capacity. Our results indicate that surface properties and aqueous solution chemistry play important roles in TC adsorption on MWCNTs.

Yu, Fei; Ma, Jie; Han, Sheng

2014-01-01

257

Highly selective adsorption of methanol in carbon nanotubes immersed in methanol-water solution  

NASA Astrophysics Data System (ADS)

The systems of open-ended carbon nanotubes (CNTs) immersed in methanol-water solution are studied by molecular dynamics simulations. For the (6,6) CNT, nearly pure methanol is found to preferentially occupy interior space of the CNT. Even when the mass fraction (MF) of methanol in bulk solution is as low as 1%, the methanol MF within the CNT is still more than 90%. For CNTs with larger diameters, the methanol concentrations within CNTs are also much higher than those outside CNTs. The methanol selectivity decreases with increasing CNT diameter, but not monotonically. From microscopic structural analyses, we find that the primary reason for the high selectivity of methanol by CNTs lies on high preference of methanol in the first solvation shell near the inner wall of CNT, which stems from a synergy effect of the van der Waals interaction between CNT and the methyl groups of methanol, together with the hydrogen bonding interaction among the liquid molecules. This synergy effect may be of general significance and extended to other systems, such as ethanol aqueous solution and methanol/ethanol mixture. The selective adsorption of methanol over water in CNTs may find applications in separation of water and methanol, detection of methanol, and preservation of methanol purity in fuel cells.

Zhao, Wen-Hui; Shang, Bo; Du, Sheng-Ping; Yuan, Lan-Feng; Yang, Jinlong; Cheng Zeng, Xiao

2012-07-01

258

Hydrophilic solutes in modified carbon dioxide extraction-prediction of the extractability using molecular dynamic simulation.  

PubMed

Super- and subcritical carbon dioxide (CO2) extractions of crude drugs were simulated by molecular modelling to predict the extractability of different hydrophilic plant constituents under various extraction conditions. The CO2 extraction fluids were simulated either with pure CO2 or with solvent modified CO2 at different pressures and temperatures. Molecular modelling resulted in three different solubility parameters: the total solubility parameter delta and the partial solubility parameters delta(d) for the van der Waals and delta(EL) for the polar forces. Thus, delta(EL) enabled the estimation of the polarity of the extraction fluids and the solute molecules. If the value of delta(EL) of the extraction fluid reached the value of the solute molecule in the crude drug, i.e. minimum extraction value, the compound was soluble at the distinct extraction conditions. For a further increase in yield of the hydrophilic solutes, the polarity of the extraction fluid had to be increased, too. That means delta(EL) of the fluid exceeded the minimum extraction value. All simulations were verified by CO2 extractions of the secondary roots of Harpagophytum procumbens (harpagoside, stachyose) and the seeds of Aesculus hippocastanum (aescin). CO2 extractions of the flowers of Matricaria recutita ((-)-alpha-bisabolol) were obtained from literature data. These four constituents with different properties, like molecular size and the allocation of polar functional groups were extracted, analysed, simulated and the extract content was correlated with the extraction fluid used, respectively. PMID:15911229

Günther, Martina; Maus, Martin; Wagner, Karl Gerhard; Schmidt, Peter Christian

2005-06-01

259

Adsorption of tetracycline from aqueous solutions onto multi-walled carbon nanotubes with different oxygen contents.  

PubMed

Oxidized multi-walled carbon nanotubes (MWCNTs) with different oxygen contents were investigated for the adsorption of tetracycline (TC) from aqueous solutions. As the surface oxygen content of the MWCNTs increased, the maximum adsorption capacity and adsorption coefficient of TC increased to the largest values and then decreased. The relation can be attributed to the interplay between the nanotubes' dispersibility and the water cluster formation upon TC adsorption. The overall adsorption kinetics of TC onto CNTs-3.2%O might be dependent on both intra-particle diffusion and boundary layer diffusion. The maximum adsorption capacity of TC on CNTs-3.2%O was achieved in the pH range of 3.3-8.0 due to formation of water clusters or H-bonds. Furthermore, the presence of Cu(2+) could significantly enhanced TC adsorption at pH of 5.0. However, the solution ionic strength did not exhibit remarkable effect on TC adsorption. In addition, when pH is beyond the range (3.3-8.0), the electrostatic interactions caused the decrease of TC adsorption capacity. Our results indicate that surface properties and aqueous solution chemistry play important roles in TC adsorption on MWCNTs. PMID:24937315

Yu, Fei; Ma, Jie; Han, Sheng

2014-01-01

260

The electrochemical and mechanical properties of Ti incorporated amorphous carbon films in Hanks’ solution  

NASA Astrophysics Data System (ADS)

Ti incorporated amorphous carbon (a-C) films with variant Ti contents were prepared by the unbalanced magnetron sputtering process. Scanning electron microscopy, ultraviolet Raman spectroscopy, X-ray photoelectron spectroscopy and transmission electron microscopy were used to characterize the microstructure of a-C films. The hardness and lubricated tribological properties were assessed using nanoindentation and ball-on-disk tribometer. As the Ti content in a-C films increases from 0 to 15.2 at.%, the sp3 volume fraction, the internal stress and the hardness of the films decreases gradually, while the disorder of sp2 bond increases. The electrochemical tests reveal that the a-C films with lower than 1.5 at.% Ti possess good corrosion resistance in Hanks' solution, while the a-C film with 15.2 at.% Ti is susceptible to crevice corrosion. The reduced friction of the a-C films is due to the sp2 bonded film surface and boundary lubrication of the Hanks' solution. The a-C film with 3.1 at.% Ti exhibits the best wear resistance in Hanks' solution among the studied films.

Hong, Chunfu; Tu, Jiangping; Liu, Dongguang; Li, Ruiling; Gu, Changdong

2010-06-01

261

Transport of carbon, nitrogen, phosphorus, and major solutes in the Gambia River, West Africa  

SciTech Connect

Transport of solutes and particulate materials and their variation with discharge were studied for 1 year (July 1980-June 1981) in the Gambia River in the tropical savanna of West Africa. The water is a dilute solution of SiO/sub 2/ and HCO/sub 3//sup -/. Na/sup +/, K/sup +/, Cl/sup -/, and total dissolved nitrogen showed no significant relation with discharge. Ca/sup 2 +/, Mg/sup 2 +/, HCO/sub 3//sup -/, conductivity, and SO/sub 4//sup 2 -/ decreased as discharge increased, while total dissolved phosphorus increased with discharge. After an initial increase SiO/sub 2/ was independent of discharge. Dissolved organic carbon displayed counterclockwise hysteresis with rising and falling discharge. Particulate phosphorus and total particulate materials displayed clockwise hysteresis. Total transport amounted to 9.66 t x km/sup -2/ x yr/sup -1/. The transport rates of both dissolved and particulate organic C are among the lowest ever reported. The low transport of total particulates and solutes is attributed to lack of relief and the lithology of the catchment.

Lesack, L.F.W.; Hecky, R.E.; Melack, J.M.

1984-07-01

262

Secondary froth wash. [Oil Sand Processing  

Microsoft Academic Search

A process is described for the removal of bitumen from secondary froth formed during the hot-water processing of Athabasca tar sands. More particularly, the process utilizes the intimate contacting of a hot water wash with a secondary froth and subsequent intimate contacting of the bitumen with the fresh hot water. The amount of solids in a secondary froth is reduced

Kaminsky

1973-01-01

263

TANK 4 CHARACTERIZATION, SETTLING, AND WASHING STUDIES  

Microsoft Academic Search

A sample of PUREX sludge from Tank 4 was characterized, and subsequently combined with a Tank 51 sample (Tank 51-E1) received following Al dissolution, but prior to a supernate decant by the Tank Farm, to perform a settling and washing study to support Sludge Batch 6 preparation. The sludge source for the majority of the Tank 51-E1 sample is Tank

C. Bannochie; J. Pareizs; D. Click; J. Zamecnik

2009-01-01

264

Washed Out Bridge, Snake Creek Near Whitesburg  

USGS Multimedia Gallery

Tributary to Snake Creek, near Whitesburg, Georgia, showing a washed out bridge. When bridges such as this one collapse during a flood, it is rarely the pressure of the rushing water against the bridge that causes the bridge to fail. Rather, the rushing water erodes the ground underneath and surroun...

2009-10-01

265

Wash resistance of insecticide-treated materials  

Microsoft Academic Search

The effectiveness of insecticide-treated materials (ITMs) for malaria control is reduced by washing them. This research in Colombia and Bolivia investigated the resistance of different insecticide formulations and, in particular, a commercially available impregnated bednet (PermaNet®) which provides chemical protection for the insecticide. The fabrics studied were all polyester; the pyrethroids used for impregnation were deltamethrin (tablet and suspension concentrate

JoséOrdóñez González; Axel Kroeger; Ana Isabel Aviña; Eulides Pabón

2002-01-01

266

Washing of the AW-101 entrained solids  

SciTech Connect

BNFL Inc. (BNFL) is under contract with the US Department of Energy, River Protection Project (DOE-RPP) to design, construct, and operate facilities for treating wastes stored in the single-shell and double-shell tanks at the Hanford Site, Richland, Washington. The DOE-BNFL RPP contract identifies two feeds to the waste treatment plant: (1) primarily liquid low-activity waste (LAW) consisting of less than 2 wt% entrained solids and (2) high-level waste (HLW) consisting of 10 to 200 g/L solids slurry. This report describes the results of a test conducted by Battelle to assess the effects of inhibited water washing on the composition of the entrained solids in the diluted AW-101 low-activity waste (LAW) sample. The objective of this work was to gather data on the solubility of the AW-101 entrained solids in 0.01 M NaOH, so that BNFL can evaluate whether these solids require caustic leaching. The work was conducted according to test plan BNFL-TP-29953-9, Rev. 0, LAW Entrained Solids Water Wash and Caustic Leach Testing. The test went according to plan, with no deviations from the test plan. Based on the results of the 0.01 M NaOH washing, a decision was made by BNFL to not proceed with the caustic leaching test. The composition of the washed solids was such that caustic leaching would not result in significant reduction in the immobilized HLW volume.

GJ Lumetta

2000-03-31

267

EVALUATION OF THE BIOGENESIS SOIL WASHING TECHNOLOGY  

EPA Science Inventory

The BioGenesis Enterprises, Inc. (BioGenesis) soil washing technology was demonstrated as part of the US Environmental Protection Agency's (EPA) Superfund Innovative Technology Evaluation (SITE) program in November 1992. he demonstration was conducted over three days at a petrole...

268

EVALUATION OF THE BIOGENESIS SOIL WASHING TECHNOLOGY  

EPA Science Inventory

The BioGenesis Enterprises, Inc. (BioGenesis) soil washing technology was demonstrated as part of the US Environmental Protection Agency's (EPA) Superfund Innovative Technology Evaluation (SITE) program in November 1992. The demonstration was conducted over three days at a petrol...

269

Prototype wash water renovation system integration with government-furnished wash fixture  

NASA Technical Reports Server (NTRS)

The requirements of a significant quantity of proposed life sciences experiments in Shuttle payloads for available wash water to support cleansing operations has provided the incentive to develop a technique for wash water renovation. A prototype wash water waste renovation system which has the capability to process the waste water and return it to a state adequate for reuse in a typical cleansing fixture designed to support life science experiments was investigated. The resulting technology is to support other developments efforts pertaining to water reclamation by serving as a pretreatment step for subsequent reclamation procedures.

1984-01-01

270

Effectiveness of hand washing and disinfection methods in removing transient bacteria after patient nursing.  

PubMed Central

The effectiveness of various hand washing and disinfection methods in removing transient skin bacteria was studied in hospital after dry or moist contamination of the hands when nursing burn patients. The results were compared with those of laboratory tests with volunteers. A fairly good correlation of the bacterial reductions existed between hospital and laboratory tests. All other methods removed Staph. aureus from the hands more effectively than liquid soap. Gram-negative bacilli were more easily removed than staphylococci, even with soap wash alone. In hospital, none of the washing and disinfection methods always removed all patient-borne bacteria from the hands. After dry or moist contamination and subsequent washing with soap only, colonies of Staph. aureus were often detected in finger-print samples. Staphylococci were more often completely removed by a 4% chlorhexidine detergent scrub and alcoholic solutions (either with or without previous soap wash) than by liquid soap, hexachlorophene or iodophor preparations. Gram-negative bacilli were more easily removed by all the washing and disinfection methods. After moist contamination, Gram-negative bacilli were more often completely removed from the hands by ethanol than by other treatments. The results of the present study emphasize the importance of always using gloves when nursing a profuse spreader of bacteria or one who must be protected from infection.

OjajA?rvi, J.

1980-01-01

271

Effectiveness of hand washing and disinfection methods in removing transient bacteria after patient nursing.  

PubMed

The effectiveness of various hand washing and disinfection methods in removing transient skin bacteria was studied in hospital after dry or moist contamination of the hands when nursing burn patients. The results were compared with those of laboratory tests with volunteers. A fairly good correlation of the bacterial reductions existed between hospital and laboratory tests. All other methods removed Staph. aureus from the hands more effectively than liquid soap. Gram-negative bacilli were more easily removed than staphylococci, even with soap wash alone. In hospital, none of the washing and disinfection methods always removed all patient-borne bacteria from the hands. After dry or moist contamination and subsequent washing with soap only, colonies of Staph. aureus were often detected in finger-print samples. Staphylococci were more often completely removed by a 4% chlorhexidine detergent scrub and alcoholic solutions (either with or without previous soap wash) than by liquid soap, hexachlorophene or iodophor preparations. Gram-negative bacilli were more easily removed by all the washing and disinfection methods. After moist contamination, Gram-negative bacilli were more often completely removed from the hands by ethanol than by other treatments. The results of the present study emphasize the importance of always using gloves when nursing a profuse spreader of bacteria or one who must be protected from infection. PMID:6778914

Ojajärvi, J

1980-10-01

272

Impact of solution chemistry on viral removal by a single-walled carbon nanotube filter.  

PubMed

This study investigates the effectiveness of a single-walled carbon nanotube (SWNT) filter for removal of viruses from water. MS2 bacteriophage viral removal was examined over a range of environmentally relevant solution chemistries, spanning various ionic strengths, monovalent and divalent salts, pH, and natural organic matter (NOM) concentrations. Viral removal by the SWNT filter was governed by physicochemical (depth) filtration. The removal of viruses increased at higher ionic strengths (NaCl) due to suppression of repulsive electrostatic interactions between viruses and SWNTs. Addition of divalent salts, however, had varying impacts. While CaCl(2) increased virus removal, likely due to complexation of calcium ions to viral surfaces, addition of MgCl(2) reduced viral removal by the SWNT filter. Solution pH also had significant impact on viral removal as the interactions between viral particles and SWNTs changed from attractive below the virus isoelectric point (about pH 3.9) to repulsive at higher pH. Suwannee River NOM was shown to be detrimental to filter viral removal. Reduction of viral removal by NOM was attributed to adsorption of NOM macromolecules to viruses and SWNTs, thereby resulting in steric repulsive forces. Modifications of the filter to incorporate thicker SWNT layers mitigate the negative impacts of NOM on filter performance. This study has shown that while it is possible to attain high levels of viral removal over a broad range of solution chemistries, the extent of viral removal will be highly dependent on the specific solution chemistry of the treated water. PMID:20569966

Brady-Estévez, Anna S; Nguyen, Thanh H; Gutierrez, Leonardo; Elimelech, Menachem

2010-07-01

273

Water movement and solute transport in permafrost wetlands: implications for inorganic carbon cycling  

NASA Astrophysics Data System (ADS)

Carbon dioxide emissions from thawing permafrost wetlands are an expected consequence of global warming. Addressing the pathways by which carbon is emitted, we investigated the hydrological and geochemical controls on the pore water chemistry of a permafrost wetland, with a shallow geological sequence comprising loam overlain by sphagnum peat, in Ilulissat, Greenland. A 400 m transect parallel to the general flow direction was established, along which water table measurements and slug tests were conducted, and the active layer thickness recorded (typically ~0.5 m). Also, in three detailed profiles along the transect, the vertical distributions of stable isotopes of water and major ion chemistry were investigated, by analysis of active layer pore water and water of melted core sections of permafrost. Concentrations of chloride (0.3-0.4 mM) did not show variation with depth, dismissing solute movement by ion freeze-out during fall freeze-up as a main control on the water chemistry. In addition, the observed vertical ?18O distribution did not to any extent conform to modelled Rayleigh distillation curves for the preferential inclusion of H218O into ice, which could be a scenario for fall freeze-up. The ?18O data therefore suggests either a rapid freeze-up or a simultaneous phase transition at all depths of the active layer, which in either case also would minimize potential ion freeze-out effects. Nevertheless, concentrations of major ions generally increased with depth. A conceptual model for water and solute transport was therefore established, according to which solutes are mobilized by weathering reactions in the loam and then transported upwards to the peat by diffusion. In the peat, lateral advective solute transport dominates. We applied the model to observed profiles of Ca, Mg, HCO3 and the partial CO2 pressure (PCO2). Concentrations of Ca, Mg and HCO3 increased with depth, reaching ~2 mM, ~2 mM and ~8 meq/L at the bottom of the active layer. Pore water at all depths was of Ca-Mg-HCO3 type (1:1:4 stoichiometry), and was subsaturated for calcite and dolomite. Immediately below the permafrost table, however, Ca, Mg and HCO3 showed an abrupt decrease. Similarly, highly elevated PCO2 of up to 1.8 atm were observed in the active layer, followed by an abrupt decrease to

Jessen, Søren; Dahl Holmslykke, Hanne; Rasmussen, Kristine; Richardt, Niels; Engelund Holm, Peter

2014-05-01

274

Kinetic study of carbon dioxide reaction with tertiary amines in aqueous solutions  

SciTech Connect

Reaction kinetics of CO/sub 2/ with triethanolamine (TEA) and methyldiethanolamine (MDEA) in aqueous solution have been studied by using a stopped-flow technique with pH detection. Rate constants are obtained from the comparison of experimental and theoretical curves giving the optical density as a function of time. At concentrations of CO/sub 2/ well below the saturation limit, the results are consistent with the hydration reactions of the CO/sub 2/ molecules either with neutral water molecules or with hydroxide ions, depending upon the pH, itself governed by the ionization equilibrium of the dissolved amine. Moreover, a specific (catalytic) reaction, first order with respect to both carbon dioxide and amine (rate constant, 2.85 M/sup -1/ s/sup -1/ at 25/sup 0/C), has been shown to contribute significantly to the reaction rate in the case of the first amine (TEA) only.

Barth, D.; Tondre, C.; Lappai, G.; Delpuech, J.J.

1981-11-26

275

Surface decoration and dispersibility of carbon nanofibers in aqueous surfactant solution  

NASA Astrophysics Data System (ADS)

As a novel functional nanomaterial, the dispersion effect of carbon nanofibers (CNFs) has a significant influence on the application of CNFs in the composites. Two effective surfactants, methylcellulose (MC) and polycarboxylate superplasticizer, were used to analyze the dispersion of CNFs in aqueous solution. A method utilizing ultrasonic processing was employed to achieve a homogenous CNF suspension, and the dispersion effect was further characterized by the method of measuring ultraviolet absorbency (UV absorbency), zeta potential, surface tension and transmission electron microscopy (TEM) micrographs. The results show that the zeta potential and surface tension reach the saturation plateau at MC concentration and polycarboxylate superplasticizer concentration of about 0.4 and 0.8 g/L, respectively, which reflects that the optimum concentration ratio of MC to CNFs is 2: 1, and the optimum dispersing polycarboxylate superplasticizer to CNFs ratio of 4: 1 is required to achieve dispersions with maximum achievable dispersion of CNFs.

Wang, B. M.; Zhang, Y.; Liu, S.

2014-03-01

276

Thermally and Environmentally Stable Carrier Doping Using a Solution Method in Carbon Nanotube Films  

NASA Astrophysics Data System (ADS)

In the present paper, we report the thermal stability of a single-walled carbon nanotube (SWCNT) film that was doped using tetrafluorotetracyano-p-quinodimethane (F4TCNQ). The SWCNTs were doped using a vapor method and a solution method, and their thermostabilities were characterized using a gas chromatography/mass spectrometer (GC/MS) and resistance measurements. These measurements clearly demonstrated the high thermal stability of F4TCNQ and the strong charge-transfer interaction between the SWCNTs and the dopants. As a result, we successfully observed an excellent long-term (longer than 500 h) thermal resistance up to 150 °C, which is a sufficient level of stability for the practical use of this dopant.

Sasaki, Yorihiko; Okimoto, Haruya; Yoshida, Kenji; Ono, Yasuichi; Iwasa, Yoshihiro; Takenobu, Taishi

2011-08-01

277

Heterogeneous adsorption of activated carbon nanofibers synthesized by electrospinning polyacrylonitrile solution.  

PubMed

This study focuses on the adsorption properties of activated carbon nanofibers (CNFs) fabricated by electrospinning polyacrylonitrile solutions dissolved in dimethylformamide, followed by heat treatment at high activation temperatures (700, 750, 800 degrees C). The samples were characterized by BET, SEM, and XRD. In addition, the adsorption energy distribution functions of CNFs were analyzed by using the generalized nonlinear regularization method. Comparative analysis of energy distribution functions provided significant information on the energetic and structural heterogeneities of CNFs. Furthermore, an investigation of adsorption equilibrium and kinetics of methylene blue (MB) and congo red (CR) revealed that the adsorption capacity and kinetics of MB are much higher and faster than that of CR on a given sample. Our experimental and theoretical results suggest that the CNFs used in this work may be widely used as an adsorbent. PMID:17252815

Lee, Jae-Wook; Kang, Hyun-Chul; Shim, Wang-Geun; Kim, Chan; Yang, Kap-Seung; Moon, Hee

2006-11-01

278

True solutions of single-walled carbon nanotubes for assembly into macroscopic materials.  

PubMed

Translating the unique characteristics of individual single-walled carbon nanotubes into macroscopic materials such as fibres and sheets has been hindered by ineffective assembly. Fluid-phase assembly is particularly attractive, but the ability to dissolve nanotubes in solvents has eluded researchers for over a decade. Here, we show that single-walled nanotubes form true thermodynamic solutions in superacids, and report the full phase diagram, allowing the rational design of fluid-phase assembly processes. Single-walled nanotubes dissolve spontaneously in chlorosulphonic acid at weight concentrations of up to 0.5 wt%, 1,000 times higher than previously reported in other acids. At higher concentrations, they form liquid-crystal phases that can be readily processed into fibres and sheets of controlled morphology. These results lay the foundation for bottom-up assembly of nanotubes and nanorods into functional materials. PMID:19893518

Davis, Virginia A; Parra-Vasquez, A Nicholas G; Green, Micah J; Rai, Pradeep K; Behabtu, Natnael; Prieto, Valentin; Booker, Richard D; Schmidt, Judith; Kesselman, Ellina; Zhou, Wei; Fan, Hua; Adams, W Wade; Hauge, Robert H; Fischer, John E; Cohen, Yachin; Talmon, Yeshayahu; Smalley, Richard E; Pasquali, Matteo

2009-12-01

279

Hybrid transparent electrodes of silver nanowires and carbon nanotubes: a low-temperature solution process  

NASA Astrophysics Data System (ADS)

Hybrid transparent electrodes with silver nanowires (AgNWs) and single-walled carbon nanotubes (SWCNTs) were fabricated on plastic films by a low-temperature solution process. The hybrid transparent electrodes exhibited a sheet resistance of 29.2 ?/sq with a transparency of 80% when 6 wt.% of SWCNTs was mixed with AgNWs. This sheet resistance was less than one-fourth that of the AgNW transparent electrodes that were prepared using the same method. This reduction in sheet resistance is because the SWCNTs formed bridges between the AgNWs, thus, resulting in high conductivity of the hybrid transparent electrodes. The hybrid electrodes formed on plastic films exhibited high conductivity as well as excellent stability in sheet resistance when tested using a repeated bending test. PACS: 62.23.Hj; 61.48.De; 81.15.-z.

Tokuno, Takehiro; Nogi, Masaya; Jiu, Jinting; Suganuma, Katsuaki

2012-05-01

280

Adsorption of fluoranthene in surfactant solution on activated carbon: equilibrium, thermodynamic, kinetic studies.  

PubMed

Adsorption of fluoranthene (FLA) in surfactant solution on activated carbon (AC) was investigated. Isotherm, thermodynamic, and kinetic attributes of FLA adsorption in the presence of the surfactant on AC were studied. Effects of AC dosage, initial concentration of TX100, initial concentration of FLA, and addition of fulvic acid on adsorption were studied. The experimental data of both TX100 and FLA fitted the Langmuir isotherm model and the pseudo-second-order kinetic model well. Positive enthalpy showed that adsorption of FLA on AC was endothermic. The efficiency of selective FLA removal generally increased with increasing initial surfactant concentration and decreasing fulvic acid concentration. The surface chemistry of AC may determine the removal of polycyclic aromatic hydrocarbons. The adsorption process may be controlled by the hydrophobic interaction between AC and the adsorbate. The microwave irradiation of AC may be a feasible method to reduce the cost of AC through its regeneration. PMID:23979852

Liu, Jianfei; Chen, Jiajun; Jiang, Lin; Wang, Xingwei

2014-02-01

281

Carbon coating of anatase-type TiO 2 through their precipitation in PVA aqueous solution  

Microsoft Academic Search

Fine particles of photocatalytic anatase-type TiO2 prepared through hydrolysis of titanium-tetraisopropoxide were coated by carbon through their precipitation in poly(vinyl alcohol) (PVA) aqueous solution, followed by heat treatment at high temperatures of 400–1000°C in a flow of high purity Ar. Without carbon coating, the phase transformation from anatase to rutile started above 600°C, but it was suppressed up to 800°C

Michio Inagaki; Yumiko Hirose; Takafumi Matsunaga; Tomoki Tsumura; Masahiro Toyoda

2003-01-01

282

Pd-loaded carbon felt as the cathode for selective dechlorination of 2,4-dichlorophenoxyacetic acid in aqueous solution  

Microsoft Academic Search

Electrocatalytic reductive dehalogenation of 2,4-dichlorophenoxyacetic acid (2,4-D) to phenoxyacetic acid in aqueous solution containing MeOH, trifluoroacetic acid, and tetraalkylammonium salt was studied. A Teflon-made two-compartment flow-through cell with a permeable carbon felt cathode and a platinum foil anode was employed. Several noble metals were tested as electrocatalysts. Palladium-loaded carbon felt was found to be the most suitable significantly enhanced its

Andrey I. Tsyganok; Ichiro Yamanaka; Kiyoshi Otsuka

1998-01-01

283

Kinetics of catalytic oxidation of sulfide in aqueous solutions on activated carbon and slime of green lye  

SciTech Connect

The kinetics of heterogeneous catalytic oxidation of sulfide ion in alkali solutions by dissolved oxygen with activated carbon and the carbon component of the slime of green lye (the waste of paper and pulp production) as the catalysts has been studied experimentally. The apparent and actual rate constants of the oxidation are measured within the framework of the model of the first order reaction under diffusive limitations.

Yakovlev, V.A.; Andreev, S.B. [St. Petersburg Technological Institute (Russian Federation)

1993-12-20

284

STM study on graphite\\/electrolyte interface in lithium-ion batteries: solid electrolyte interface formation in trifluoropropylene carbonate solution  

Microsoft Academic Search

Lithium intercalation within graphite was studied in an electrolyte system, 1 M LiClO4 dissolved in trifluoropropylene carbonate (TFPC). Lithium was intercalated within graphite in TFPC. The reversible capacity obtained (275 mAh g?1) was smaller than that in ethylene carbonate-based solutions while the irreversible capacity was larger (335 mAh g?1). The morphology change of the basal plane of highly oriented pyrolytic

Minoru Inaba; Yutaka Kawatate; Atsushi Funabiki; Soon-Ki Jeong; Takeshi Abe; Zempachi Ogumi

1999-01-01

285

Fabrication of transparent and conductive carbon nanotube/polyvinyl butyral films by a facile solution surface dip coating method  

NASA Astrophysics Data System (ADS)

We present a simple solution surface dip coating method for fabricating transparent and conductive carbon nanotube/polyvinyl butyral (CNT/PVB) composite films. This fabrication process is simple to scale production and requires only ethanol and water as solvents, which is green and environment friendly.We present a simple solution surface dip coating method for fabricating transparent and conductive carbon nanotube/polyvinyl butyral (CNT/PVB) composite films. This fabrication process is simple to scale production and requires only ethanol and water as solvents, which is green and environment friendly. Electronic supplementary information (ESI) available: Experimental section. See DOI: 10.1039/c1nr10302d

Li, Yuanqing; Yu, Ting; Pui, Tzesian; Chen, Peng; Zheng, Lianxi; Liao, Kin

2011-06-01

286

Pd-loaded carbon felt as the cathode for selective dechlorination of 2,4-dichlorophenoxyacetic acid in aqueous solution  

SciTech Connect

Electrocatalytic reductive dehalogenation of 2,4-dichlorophenoxyacetic acid (2,4-D) to phenoxyacetic acid in aqueous solution containing MeOH, trifluoroacetic acid, and tetraalkylammonium salt was studied. A Teflon-made two-compartment flow-through cell with a permeable carbon felt cathode and a platinum foil anode was employed. Several noble metals were tested as electrocatalysts. Palladium-loaded carbon felt was found to be the most suitable significantly enhanced its electrocatalytic activity toward 2,4-D dechlorination. The reaction was hypothesized to proceed at carbon-palladium interface areas through 4-chlorine cleavage to form 2-chlorophenoxyacetic acid as the main reaction intermediate.

Tsyganok, A.I.; Yamanaka, Ichiro; Otsuka, Kiyoshi [Tokyo Inst. of Tech. (Japan). Dept. of Chemical Engineering

1998-11-01

287

Development and distribution of bed-parallel compaction bands and pressure solution seams in carbonates (Bolognano Formation, Majella Mountain, Italy)  

NASA Astrophysics Data System (ADS)

The Oligo-Miocene carbonates pertaining to the Bolognano Formation, cropping out at the Majella Mountain, Italy, are diffusely crosscut by bed-parallel structural elements such as compaction bands and pressure solution seams. These bed-parallel structural elements formed under a vertical loading, during the progressive burial of the carbonates. The present work focuses on the control exerted on their development and distribution by compositional, sedimentological and pore network characteristics of the studied carbonates. The main results are consistent with the following statements: (i) bed-parallel compaction bands developed only within the poorly cemented, porous grainstones (2D porosity > 10%; 3D porosity > 15%); (ii) distribution of these bands was strongly controlled by both sorting and sphericity of the carbonate grains, as well as by the amount of intergranular macroporosity; (iii) bed-parallel pressure solution seams formed, mainly, within the fine-grained packstones, which are characterized by small amounts of clayish matrix (2-4% of total rock volume), and well-sorted, spherical carbonate grains. Considering the impact that burial-related, bed-parallel structures may have on fluid flow, the results provided in this contribution can help the management of subsurface geofluids, and overall prediction of carbonate reservoir quality, by mapping/simulating/assessing carbonate facies.

Rustichelli, Andrea; Tondi, Emanuele; Agosta, Fabrizio; Cilona, Antonino; Giorgioni, Maurizio

2012-04-01

288

Elution of zinc in dust discharged from electric arc furnace in carbonic acid solution  

NASA Astrophysics Data System (ADS)

The dust discharged from an electric arc furnace (EAF) is a valuable resource of zinc. As a fundamental study of extraction of zinc, iron and chlorine in the EAF dust, the elution behavior of them in carbonic acid solution was studied. The influence of the weight of the EAF dust on the elution behavior was examined in this study. Experiment was carried out putting the EAF dust from 1 g to 200 g in weight into 1 L of water that was introduced by CO2. Generally, the pH in the aqueous solution increased with an increase in weight of the additive EAF dust. Maximums of the eluted concentrations of zinc and chloride ion increased with an increase in the weight of the additive EAF dust whereas the extraction ratios of both of them decreased with an increase in the weight of the additive EAF dust. Iron in the EAF dust remained in the dust without elution. The limit of extraction of zinc from the EAF dust to water was given by the solubilities of ZnFe2O4 and ZnO expressed by eq. (6) and eq. (9) respectively.

Yokoyama, S.; Sasaki, T.; Sasano, J.; Izaki, M.

2012-03-01

289

Optimization of process parameters of polymer solution mediated growth of calcium carbonate nanoparticles.  

PubMed

With the advent of nanotechnology, many methods of synthesis of nanoparticles have come into practice and the 'polymer mediated growth' technique is among them. In this route, ions of one of the reactants are allowed to diffuse from an external solution into a polymer matrix where the other reactant is complexed and bound. The exact role of ionic diffusion in the formation of nanoparticles was investigated in the current study by studying the patterns of kinetics of nanoparticle formation using UV vis spectroscopy. Typically, calcium carbonate nanoparticles were formed by the aforementioned technique using polyethylene glycol solution. The particle size was calculated using Scherrer's formula on x-ray diffraction plots and was reconfirmed with field emission scanning electron microscope and transmission electron microscope images. Energy-dispersive x-ray analysis was used to study the composition and purity of the nanoparticles formed. The reactant to polymer ratio, reaction temperature and molecular weight of polyethylene glycol affected the size of the particles formed. Through this knowledge we optimized these parameters to obtain particles as small as 20 nm and confirmed that this technique can be used to control the size of nanoparticles. PMID:22922538

Biradar, Santoshkumar; Goornavar, Virupaxi; Periyakaruppan, Adaikkappan; Koehne, Jessica; Jeffers, Robert; Hall, Joseph C; Ramesh, Vani; Meyyappan, M; Ramesh, Govindarajan T

2012-09-21

290

Arsenic removal from aqueous solutions by adsorption onto iron oxide/activated carbon magnetic composite.  

PubMed

In this work the adsorption features of activated carbon and the magnetic properties of iron oxides were combined in a composite to produce magnetic adsorbent. Batch experiments were conducted to study the adsorption behavior of arsenate onto the synthetic magnetic adsorbent. The effects of initial solution pH, contact time, adsorbent dosage and co-existing anionic component on the adsorption of arsenate were investigated. The results showed that the removal percentage of arsenate could be over 95% in the conditions of adsorbent dosage 5.0 g/L, initial solution pH 3.0-8.0, and contact time 1 h. Under the experimental conditions, phosphate and silicate caused greater decrease in arsenate removal percentage among the anions, and sulfate had almost no effect on the adsorption of arsenate. Kinetics study showed that the overall adsorption rate of arsenate was illustrated by the pseudo-second-order kinetic model. The applicability of the Langmuir and Freundlich models for the arsenate adsorption data was tested. Both the models adequately describe the experimental data. Moreover, the magnetic composite adsorbent could be easily recovered from the medium by an external magnetic field. It can therefore be potentially applied for the treatment of water contaminated by arsenate. PMID:24602339

Yao, Shuhua; Liu, Ziru; Shi, Zhongliang

2014-01-01

291

The electrochromic behavior of indium tin oxide in propylene carbonate solutions  

SciTech Connect

The authors report on a study of transparent conducting tin-doped indium oxide (ITO) electrodes in propylene carbonate solutions containing lithium ions. The system was studied using electrochemical methods in combination with in situ techniques: ultraviolet-visible spectroscopy, X-ray diffraction, and quartz crystal microbalance. The results show that the cathodic process at E {approx_gt} 1.0 V vs. Li/Li{sup +} mainly involves the reduction of the electrolyte solution, leading to the formation of a thin, lithium-rich surface film. At potentials {approx_lt}1.0 V vs. Li/Li{sup +}, degradation of ITO and the formation of metallic indium take place. No evidence was obtained that lithium-ion intercalation into ITO, which has been suggested by several workers, occurs to a significant extent. The authors conclude that ITO probably cannot be used as a combined ion-storage layer and transparent conductor for all-solid-state and laminated electrochromic switching devices in view of long-term stability.

Bressers, P.M.M.C. [Philips Research, Eindhoven (Netherlands)]|[Utrecht Univ. (Netherlands). Debye Inst.; Meulenkamp, E.A. [Philips Research, Eindhoven (Netherlands)

1998-07-01

292

Extraction of lanthanides from acidic solution using tributyl phosphate modified supercritical carbon dioxide  

SciTech Connect

The feasibility of using supercritical carbon dioxide as a substitute extraction solvent in nuclear reprocessing was tested by the extraction of lanthanide ions from acidic solution. Lanthanides were extracted from 6 M HNO[sub 3]-3 M LiNO[sub 3] solutions using tributyl phosphate- (TBP-) modified CO[sub 2]. Synergistic effects were also investigated using a combination of thenoyltrifluoroacetone (TTA) and TBP-modified CO[sub 2] as the extractant. It was found that near-quantitative extraction of Sm[sup 3+], Eu[sup 3+], Gd[sup 3+], and Dy[sup 3+] was achieved while the extraction efficiencies for La[sup 3+], Ce[sup 3+], Yb[sup 3+], and Lu[sup 3+] were much lower. The light lanthanides extracted as Ln(NO[sub 3])[sub 3][center dot]3TBP and the heavy lanthanides extracted as Ln(NO[sub 3])[sub 3][center dot]2TBP when TBP-modified CO[sub 2] was used as the extractant, while Ln(TTA)[sub 3][center dot] 3TBP and Ln(TTA)[sub 3][center dot]2TBP adducts were extracted when TTA was added to TBP-modified CO[sub 2]. 17 refs., 1 fig., 3 tabs.

Laintz, K.E.; Tachikawa, E. (Japan Atomic Energy Research Inst., Ibaraki-Ken (Japan))

1994-07-01

293

Effects of washing methods on gel properties of chicken surimi prepared from spent hen breast muscle.  

PubMed

In this study, 2 myofibrillar protein extraction methods were compared for the preparation of chicken surimi using spent hen breast muscle. One method involved 1 washing with 0.1, 0.5, or 1% sodium chloride solution followed by 2 washings with distilled water, with homogenization and centrifugation of the breast muscle after each washing (new method; NM). The other method used only distilled water for the extraction, and washing was repeated 3 times followed by homogenization and centrifugation of the breast muscle after each washing (conventional method; CM). The redness values of the batter as well as the cooked gel were significantly lower (P < or = 0.05) by NM as compared with CM. In addition, the SDS-PAGE of NM sarcoplasmic protein fractions showed phosphorylase bands with increased staining intensity as compared with CM, indicating that brightness was related to the sarcoplasmic protein fractions. Overall, the data implied that sodium chloride solution was more appropriate for the myofibrillar protein extraction of spent hen breast muscle than the commonly used distilled water method. PMID:19531715

Kang, G H; Kim, S H; Kim, J H; Kang, H K; Kim, D W; Na, J C; Yu, D J; Suh, O S; Choi, Y H

2009-07-01

294

Purification of aqueous plutonium chloride solutions via precipitation and washing.  

SciTech Connect

Pyrochemical operations at Los Alamos Plutonium Facility (TA-55) use high temperature melt s of calcium chloride for the reduction of plutonium oxide to plutonium metal and hi gh temperature combined melts of sodium chloride and potassium chloride mixtures for the electrorefining purification of plutonium metal . The remaining plutonium and americium are recovered from thes e salts by dissolution in concentrated hydrochloric acid followed by either solvent extraction or io n exchange for isolation and ultimately converted to oxide after precipitation with oxalic acid . Figur e 1 illustrates the current aqueous chloride flow sheet used for plutonium processing at TA-55 .

Stroud, M. A. (Mary Ann); Salazar, R. R. (Richard R.); Abney, Kent David; Bluhm, E. A. (Elizabeth A.); Danis, J. A. (Janet A.)

2003-01-01

295

Ca-Rich Carbonate Melts: A Regular-Solution Model, with Applications to Carbonatite Magma + Vapor Equilibria and Carbonate Lavas on Venus  

NASA Technical Reports Server (NTRS)

A thermochemical model of the activities of species in carbonate-rich melts would be useful in quantifying chemical equilibria between carbonatite magmas and vapors and in extrapolating liquidus equilibria to unexplored PTX. A regular-solution model of Ca-rich carbonate melts is developed here, using the fact that they are ionic liquids, and can be treated (to a first approximation) as interpenetrating regular solutions of cations and of anions. Thermochemical data on systems of alkali metal cations with carbonate and other anions are drawn from the literature; data on systems with alkaline earth (and other) cations and carbonate (and other) anions are derived here from liquidus phase equilibria. The model is validated in that all available data (at 1 kbar) are consistent with single values for the melting temperature and heat of fusion for calcite, and all liquidi are consistent with the liquids acting as regular solutions. At 1 kbar, the metastable congruent melting temperature of calcite (CaCO3) is inferred to be 1596 K, with (Delta)bar-H(sub fus)(calcite) = 31.5 +/- 1 kJ/mol. Regular solution interaction parameters (W) for Ca(2+) and alkali metal cations are in the range -3 to -12 kJ/sq mol; W for Ca(2+)-Ba(2+) is approximately -11 kJ/sq mol; W for Ca(2+)-Mg(2+) is approximately -40 kJ/sq mol, and W for Ca(2+)-La(3+) is approximately +85 kJ/sq mol. Solutions of carbonate and most anions (including OH(-), F(-), and SO4(2-)) are nearly ideal, with W between 0(ideal) and -2.5 kJ/sq mol. The interaction of carbonate and phosphate ions is strongly nonideal, which is consistent with the suggestion of carbonate-phosphate liquid immiscibility. Interaction of carbonate and sulfide ions is also nonideal and suggestive of carbonate-sulfide liquid immiscibility. Solution of H2O, for all but the most H2O-rich compositions, can be modeled as a disproportionation to hydronium (H3O(+)) and hydroxyl (OH(-)) ions with W for Ca(2+)-H3O(+) (approximately) equals 33 kJ/sq mol. The regular-solution model of carbonate melts can be applied to problems of carbonatite magma + vapor equilibria and of extrapolating liquidus equilibria to unstudied systems. Calculations on one carbonatite (the Husereau dike, Oka complex, Quebec, Canada) show that the anion solution of its magma contained an OH mole fraction of (approximately) 0.07, although the vapor in equilibrium with the magma had P(H2O) = 8.5 x P(CO2). F in carbonatite systems is calculated to be strongly partitioned into the magma (as F(-)) relative to coexisting vapor. In the Husereau carbonatite magma, the anion solution contained an F(-) mole fraction of (approximately) 6 x 10(exp -5).

Treiman, Allan H.

1995-01-01

296

Spectroscopic and electrochemical studies of selected lanthanides and actinides in concentrated aqueous carbonate and carbonate-hydroxide solutions and in molten dimethyl sulfone  

SciTech Connect

Electrochemical and spectroscopic studies of neptunium, plutonium, americium, californium, and terbium in concentrated aqueous carbonate and carbonate-hydroxide solutions have been carried out. Changes in the absorption spectra of Np(VII), Np(V), Pu(VI), Pu(V), Am(VI), and Am(V) in concentrated Na/sub 2/CO/sub 3/ solution and in the formal potentials of the Np(VI)/Np(V) and Pu(VI)/Pu(V) couples as a function of pH were observed. Heptavalent neptunium in concentrated Na/sub 2/CO/sub 3/ solution could only be producted at pH values close to or greater than 14. Plutonium(VII) in 2 M Na/sub 2/CO/sub 3/ solution could only be produced at hydroxide ion concentrations in excess of about 2.5 M. The complexation of Np(VII) and Pu(VII) in Na/sub 2/CO/sub 3/-NaOH solution seems to be mainly by hydroxide ions. Neptunium(IV) and plutonium(IV) are insoluble in Na/sub 2/CO/sub 3/ solution above ca. pH 11-12. Neptunium(III) in carbonate solution is rapidly oxidized by water to Np(IV). Plutonium(III) is insoluble in Na/sub 2/CO/sub 3/ solution. In K/sub 2/CO/sub 3/ solution Pu(III) is stable to oxidation by water but is very sensitive to air oxidation. The redox properties of Cf(III) in Na/sub 2/CO/sub 3/ and K/sub 2/CO/sub 3/ solutions at pH values from 8 to 14 were investigated. The oxidation of terbium(III) in K/sub 2/CO/sub 3/-KOH solution was studied. Spectroscopic and electrochemical studies of cerium, samarium, europium, ytterbium, uranium, neptunium, plutonium, and americium in molten dimethyl sulfone (DMSO/sub 2/) at 400 K were performed. Differences in the DMSO/sub 2/ solution absorption spectra of trivalent Sm, Eu, and Yb and divalent Eu compared with those in aqueous solution were observed. Complexation effects on the spectra of Ce(III), Ce(IV), U(VI), Np(VI), Pu(VI), and Am(VI) are more noticeable in poorly coordinating DMSO/sub 2/ than they are in water. 123 references, 54 figures, 11 tables.

Varlashkin, P.G.

1985-03-01

297

Analytical solution of geological carbon sequestration under constant pressure injection into a horizontal radial reservoir  

NASA Astrophysics Data System (ADS)

Carbon capture and sequestration (CCS) is believed to be an economically feasible technology to mitigate global warming by capturing carbon dioxide (CO2), the major component of greenhouse gases, from the atmosphere and injecting it into deep geological formations.Several mechanisms can help trap CO2 in the pore space of a geological reservoir, stratigraphic and structural trapping, hydrodynamic trapping, and geochemical trapping.Besides these trapping mechanisms, another important issue that deserves careful attention is the risk of CO2 leakage. The common ';constant injection rate' scenario may induce high pressure buildup that will endanger the mechanical integrity as well as the sealing capability of the cap rock. Instead of injecting CO2 at a constant mass rate, CO2 can be injected into the reservoir by fixing the pressure (usually the bottom-hole pressure) in the injection borehole. By doing so, the inevitable pressure buildup associated with the constant injection scheme can be completely eliminated in the constant pressure injection scheme. In this paper, a semi-analytical solution for CO2 injection with constant pressure was developed. For simplicity, structural and geochemical trapping mechanisms were not considered. Therefore, a horizontal reservoir with infinite radial extent was considered. Prior to injection, the reservoir is fully saturated with the formation brine. It is assumed that CO2 does not mix with brine such that a sharp interface is formed once CO2 invades the brine-saturated pores. Because of the density difference between CO2 and brine, CO2 resides above the interface. Additional assumptions were also made when building up the brine and CO2 mass balance equations: (1) both of the fluids and the geological formations are incompressible, (2) capillary pressure is neglected, (3)there is no fluid flow in the vertical direction, and the horizontal flow satisfies the Darcy's law.In order to solve for the height of brine-CO2 interface, the two mass balance equations are combined into a single one by using a similarity transformation such that the two independent variables (radial distance and time) are reduced into only one similarity variable. The resulting mass balance equation is recast as a second-order ordinary differential equation, which can be treated as an initial value problem and solved conveniently by MATLAB. We have tested this solution using one hypothetical parameter set. In the next step, we will verify this analytical solution by conducting a parallel numerical simulation using TOUGH2 ECO2N. Then, characteristics of the CO2 front will be studied and compared with the Buckley-Leverett theory.

Jhang, R.; Liou, T.

2013-12-01

298

Linking process and product in terrestrial carbonates using a solution thermodynamic approach  

NASA Astrophysics Data System (ADS)

Determining the processes which generate terrestrial carbonate deposits (tufas, travertines and associated chemical sediments) is a long-standing problem. Deposition of mineral products from solution reflects a complex combination of biological, equilibrium and kinetic processes, and the differences in products these processes produce are yet to be clearly demarked. Building on the groundbreaking work of previous authors, we propose that the underlying control on the processes leading to the deposition of these products can be most parsimoniously understood from the thermodynamic properties of their source solutions. Here, we report initial observations of the differences in product generated from spring and lake systems spanning a range of temperature : supersaturation space. We find that at high supersaturation, biological influences are masked by high rates of spontaneous nucleation and sedimentary products from these settings infrequently exhibit classic "biomediated" fabrics such as clotted micrite. Likewise, at high temperature exclusion of vascular plants and complex/diverse biofilms significantly inhibits the magnitude of biomediated precipitation, again impeding the likelihood of encountering the "bio-type" fabrics. Conversely, despite the clear division in product between extensive tufa facies associations and discontinuous deposits such as oncoid beds, no clear division can be identified between these systems in temperature : supersaturation space. We reiterate the conclusion of previous authors, which demonstrate that this division cannot be made on the basis of physico-chemical characteristics of the solution alone. We further provide a new case study of this division from two adjacent systems in the UK, where continuous tufa-like deposition is happening at a site with lower supersaturation than other sites exhibiting only discontinuous (oncoidal) deposition. However, a strong microbiological division is demonstrated between these sites on the basis of suspended bacterial cell distribution, which reach a prominent maximum where tufa-like deposits are forming. We conclude that at high supersaturation, the thermodynamic properties of solutions provide a highly satisfactory means of linking process and product, raising the opportunity of identifying water characteristics from sedimentological/petrological characteristics of ancient deposits. At low supersaturation, we recommend that future research focuses on geomicrobiological processes rather than the more traditional, inorganic solution chemistry approach dominant in the past.

Rogerson, M.; Pedley, H. M.; Kelham, A.

2013-09-01

299

Washing of the AN-107 entrained solids  

SciTech Connect

This report describes the results of a test conducted by Battelle to assess the effects of inhibited water washing on the composition of the entrained solids in the diluted AN-107 low-activity waste (LAW) sample. The objective of this work was to gather data on the solubility of the AN-107 entrained solids in 0.01 M NaOH, so that BNFL can evaluate whether these solids require caustic leaching.

GJ Lumetta; FV Hoopes

2000-03-31

300

4. AERIAL VIEW OF GENE WASH RESERVOIR AND GENE CAMP ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. AERIAL VIEW OF GENE WASH RESERVOIR AND GENE CAMP LOOKING SOUTHWEST. DAM AND SPILLWAY VISIBLE IN BOTTOM OF PHOTO. - Gene Wash Reservoir & Dam, 2 miles west of Parker Dam, Parker Dam, San Bernardino County, CA

301

Without Blue Crabs, Southern Salt Marshes Wash Away  

NSF Publications Database

... of this News Tip: Without Blue Crabs, Southern Salt Marshes Wash Away Ocean Drilling Program ... Technology Research Without Blue Crabs, Southern Salt Marshes Wash Away The blue crab harvest needs ...

302

6. GENE WASH DAM, LOOKING NORTHWEST. SURVEY REFLECTOR IN FOREGROUND ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. GENE WASH DAM, LOOKING NORTHWEST. SURVEY REFLECTOR IN FOREGROUND FOR MONITORING MOVEMENT OF DAM AND EARTH. - Gene Wash Reservoir & Dam, 2 miles west of Parker Dam, Parker Dam, San Bernardino County, CA

303

Health Care Workers Wash Hands More When Patients Watching  

MedlinePLUS

... sharing features on this page, please enable JavaScript. Health Care Workers Wash Hands More When Patients Watching Canadian ... hospital, keep an eye out for hygiene practices: Health care workers are more likely to wash their hands ...

304

3. VIEW OF WEST SIDE OF WASH HOUSE TO RIGHT, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. VIEW OF WEST SIDE OF WASH HOUSE TO RIGHT, BERWIND-WHITE SITE OFFICE ON LEFT, LOOKING NORTH - Eureka No. 40, Wash House, East of State Route 56, North of Little Paint Creek, Scalp Level, Cambria County, PA

305

2. VIEW OF WEST SIDE AND NORTH FACADE OF WASH ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. VIEW OF WEST SIDE AND NORTH FACADE OF WASH HOUSE. TO RIGHT IS BERWIND-WHITE SITE OFFICE - Eureka No. 40, Wash House, East of State Route 56, North of Little Paint Creek, Scalp Level, Cambria County, PA

306

Process for Recovering the Salts of Anthraquinonedisulphonic Acid from a Washing Liquid Stream.  

National Technical Information Service (NTIS)

The invention concerns a process for recovering the salts of anthraquinone disulfonic acid (ADA) from a sub-stream of washing liquid. In the so-called Stretford process, an alkaline solution of salts of anthraquinone disulphonic acid (ADA) is used as a wa...

1985-01-01

307

Continuous concentration and constant volume washing of tetraphenylborate slurries  

SciTech Connect

SRTC has completed filtration testing of tetraphenylborate (TPB) slurries with and without sludge. These tests were slightly different from previous SRS tests in that they used continuous mode concentration and constant volume washing evolutions. The extent of TPB recovery during washing was measured. The resulting washed precipitate slurry, with sludge, was stored at ambient temperature and under a nitrogen-inerted atmosphere to study TPB stability. Samples of both unwashed and washed slurries were submitted for rheology measurements.

Siler, J.L.

1999-12-08

308

Stable isotope analysis of dissolved organic carbon in soil solutions using a catalytic combustion total organic carbon analyzer-isotope ratio mass spectrometer with a cryofocusing interface.  

PubMed

Stable carbon isotopes are a powerful tool to assess the origin and dynamics of carbon in soils. However, direct analysis of the (13)C/(12)C ratio in the dissolved organic carbon (DOC) pool has proved to be difficult. Recently, several systems have been developed to measure isotope ratios in DOC by coupling a total organic carbon (TOC) analyzer with an isotope ratio mass spectrometer. However these systems were designed for the analysis of fresh and marine water and no results for soil solutions or (13)C-enriched samples have been reported. Because we mainly deal with soil solutions in which the difficult to oxidize humic and fulvic acids are the predominant carbon-containing components, we preferred to use thermal catalytic oxidation to convert DOC into CO(2). We therefore coupled a high-temperature combustion TOC analyzer with an isotope ratio mass spectrometer, by trapping and focusing the CO(2) cryogenically between the instruments. The analytical performance was tested by measuring solutions of compounds varying in the ease with which they can be oxidized. Samples with DOC concentrations between 1 and 100 mg C/L could be analyzed with good precision (standard deviation (SD) < or = 0.6 per thousand), acceptable accuracy, good linearity (overall SD = 1 per thousand) and without significant memory effects. In a (13)C-tracer experiment, we observed that mixing plant residues with soil caused a release of plant-derived DOC, which was degraded or sorbed during incubation. Based on these results, we are confident that this approach can become a relatively simple alternative method for the measurement of the (13)C/(12)C ratio of DOC in soil solutions. PMID:20058235

De Troyer, I; Bouillon, S; Barker, S; Perry, C; Coorevits, K; Merckx, R

2010-02-01

309

Use of rice husk-based porous carbon for adsorption of Rhodamine B from aqueous solutions  

Microsoft Academic Search

This paper complements the previous one (adsorption of Malachite Green). Adsorption of Rhodamine B (RB) by rice husk-based porous carbons (RHCs) and commercial carbons from aqueous medium have been studied. Three samples of carbons prepared by NaOH activation, three samples prepared by KOH activation and two samples of commercial carbons have been used. The adsorption isotherms have been determined after

Yupeng Guo; Jingzhe Zhao; Hui Zhang; Shaofeng Yang; Jurui Qi; Zichen Wang; Hongding Xu

2005-01-01

310

Effect of yttrium and chromium ion implantation on crevice electrochemical behavior of carbon steel in sodium chloride solution  

NASA Astrophysics Data System (ADS)

In order to study the effect of yttrium (Y) and chromium (Cr) ion implantation on the crevice corrosion behavior of carbon steel, the carbon steel was implanted with Y and Cr ion using MEVVA source at an energy of 40 keV. Electrochemical measurement was employed to evaluate the crevice corrosion of implanted carbon steel in NaCl solution. The results indicated that, after Y and Cr ion implantation, the carbon steel's crevice corrosion resistance and electrochemical characteristic were significantly improved in NaCl solution when the implantation dose of Y increased. Auger electron spectroscopy (AES) analysis of the implanted carbon steel manifested that the surface layer was mainly composed of elements Fe, Cr, O, and Y. Most of element Y was located near the outside region of the surface layer/solution interface, whereas Cr was enriched in the transition area between surface layer and matrix. By X-ray photoelectron spectroscopy (XPS) analysis, the implanted Y was in the form of Y 2O 3, whereas Cr in the form of Cr 2O 3 in the surface layer. The mechanism of the crevice corrosion resistance and electrochemical characteristic improvement was that, after Y and Cr ion implantation, the surface layer seemed to be constituted by Y 2O 3 and Cr 2O 3. The surface layer acted as a barrier to reduce the metal matrix to contact with the corrosion medium such as inhibiting Cl - ions from corroding the layer.

Liang, Chenghao; Huang, Naibao

2008-12-01

311

Use of a Carbonate-Containing Process Waste in Purification of Aqueous Solutions To Remove Zinc(II) Ions  

Microsoft Academic Search

A carbonate-containing waste from water-treatment installations of thermal power plants is tested as a sorbent for purifying aqueous solutions to remove zinc(II) ions. The effect of time, temperature, and other factors on sorption is evaluated.

T. G. Lupeiko; E. M. Bayan; M. O. Gorbunova

2005-01-01

312

Removal of Metanil Yellow from its Aqueous Solution by Fly Ash and Activated Carbon Produced from Different Sources  

Microsoft Academic Search

The present study has been undertaken to observe the relative efficiency of removal of metanil yellow from its aqueous solution by using different adsorbents like fly ash and activated carbon produced from different sources i.e. coconut shell, mehagani saw dust, and rice husk. It has also been observed that the rate of adsorption is highly dependent on contact time, adsorbent

Amiya Kumar Santra; Tapan Kumar Pal; Siddhartha Datta

2008-01-01

313

POTENTIAL FOR STRESS CORROSION CRACKING OF A537 CARBON STEEL NUCLEAR WASTE TANKS CONTAINING HIGHLY CAUSTIC SOLUTIONS  

Microsoft Academic Search

The evaporator recycle streams of nuclear waste tanks may contain waste in a chemistry and temperature regime that exceeds the current corrosion control program, which imposes temperature limits to mitigate caustic stress corrosion cracking (CSCC). A review of the recent service history found that two of these A537 carbon steel tanks were operated in highly concentrated hydroxide solution at high

P. Lam; C. Stripling; D. Fisher; J. Elder

2010-01-01

314

Rayleigh and raman scattering study of orientational and vibrational relaxation of carbon disulfide and chlorobenzene in solution  

Microsoft Academic Search

We have studied the line shape of the 655 cm-1 Raman line in carbon disulfide and the 1002 cm-1 line of chlorobenzene, from which we determine the orientational and vibrational relaxation times. We present results obtained on the vibrational relaxation of chlorobenzene in solution with heptane, dimethyl sulfoxide, acetone, and quinoline. Peculiarities in the behavior of the polarized line width

A. K. Atakhodzhaev; F. Kh. Tukhvatullin; I. P. Kleiner; A. Zhumaboev; A. A. Tursunkulov

1995-01-01

315

Formation of Lubricant “Sierra” at Boundary Between Perfluoropolyether Solution Dipped and Undipped Zones over Diamond Like Carbon Coated Magnetic Disks  

Microsoft Academic Search

An unstable phenomenon arising at the boundary between perfluoropolyether (PFPE) solution dipped and undipped zones over diamond like carbon (DLC) coated magnetic disks was studied. The formation conditions of a ridge of lubricant, or “sierra,” at this boundary and the structure of the “sierra” were clarified. It was found that the “sierra” structure of the lubricant suddenly formed when withdrawing

Y. Mitsuya; K. Goto; Y. Hayashi

2004-01-01

316

Fabrication of transparent and conductive carbon nanotube/polyvinyl butyral films by a facile solution surface dip coating method.  

PubMed

We present a simple solution surface dip coating method for fabricating transparent and conductive carbon nanotube/polyvinyl butyral (CNT/PVB) composite films. This fabrication process is simple to scale production and requires only ethanol and water as solvents, which is green and environment friendly. PMID:21589986

Li, Yuanqing; Yu, Ting; Pui, Tzesian; Chen, Peng; Zheng, Lianxi; Liao, Kin

2011-06-01

317

Removal of congo red from aqueous solution by bagasse fly ash and activated carbon: Kinetic study and equilibrium isotherm analyses  

Microsoft Academic Search

Present investigation deals with the utilisation of bagasse fly ash (BFA) (generated as a waste material from bagasse fired boilers) and the use of activated carbons—commercial grade (ACC) and laboratory grade (ACL), as adsorbents for the removal of congo red (CR) from aqueous solutions. Batch studies were conducted to evaluate the adsorption capacity of BFA, ACC and ACL and the

Indra Deo Mall; Vimal Chandra Srivastava; Nitin Kumar Agarwal; Indra Mani Mishra

2005-01-01

318

Separation of single-walled carbon nanotubes from graphite by centrifugation in a surfactant or in polymer solutions  

Microsoft Academic Search

Electric arc single-walled carbon nanotubes (SWCNTs) can be separated from their graphitic impurities by a single centrifugation process in a surfactant or in polymer solutions. The purity of SWCNT dispersions, evaluated from near infrared (NIR) spectroscopy measurements, substantially increased after centrifugation at a moderate speed. The supernatant NIR purity was affected by the surfactant choice, following the sequence: sodium cholate?Pluronic

A. Ansón-Casaos; J. M. González-Domínguez; M. T. Martínez

2010-01-01

319

Application of Fly Ash and Activated Carbon in the Removal of Cu and Ni Ions from Aqueous Solutions  

Microsoft Academic Search

The main objective of this study was to remove Cu and Ni ions from aqueous solution by using fly ash, an industrial solid waste of the sugar industry and commercial activated carbon at equilibrium, which follows Langmuir and Freundlich adsorption isotherms. In order to identify influential parameters and to evaluate their interactions, effects of time, pH, initial metal concentration, and

E. Pehlivan; S. Cetin

2008-01-01

320

Why Do I Need to Wash My Hands?  

MedlinePLUS

... Society Why Do I Need to Wash My Hands? KidsHealth > Kids > Q&A > Q & A > Why Do I Need to Wash My Hands? Print A A A Text Size "Did you wash your hands?" How many times did you hear that today? ...

321

Washing Exposure Trails of Polyethylene and Poly (Vinyl Chloride).  

National Technical Information Service (NTIS)

Experiments were carried out to determine the effects, if any, of regular washing of exposed samples of polyethylene and PVC sheet. It was shown that washing, either by rain or regularly by hand over an eighteen month period does not wash away or leach ou...

M. P. Bladen E. J. Hill

1973-01-01

322

Food Worker Hand Washing Practices: An Observation Study  

Microsoft Academic Search

Improvement of food worker hand washing practices is critical to the reduction of foodborne illness and is dependent upon a clear understanding of current hand washing practices. To that end, this study collected detailed observational data on food worker hand washing practices. Food workers (n 321) were observed preparing food, and data were recorded on specific work activities for which

LAURA R. GREEN; CAROL A. SELMAN; VINCENT RADKE; DANNY RIPLEY; JAMES C. MACK; DAVID W. REIMANN; TAMMI STIGGER; MICHELLE MOTSINGER; LISA BUSHNELL

2006-01-01

323

Electrochemical reduction of carbon monoxide in the titanium(III) - molybdenum(III) - pyrocatechol system in aqueous alkaline solutions  

SciTech Connect

The electrochemical reduction of carbon monoxide to produce methane is studied. Specifically, the catalytic effects of an aqueous solution of titanium(III), molybdenum(III), and pyrocatechol are investigated. The electrochemical characteristics of the solutions are examined to determine the complexes which are formed during the reaction. It is concluded that the carbonyl complex of MO(III) is the catalytically active particle in the system. The pyrocatechol complex of Ti(III) plays the role of agent for transfer of electrons from the cathode to the active particle in the volume of the solution.

Petrova, G.N.; Efimov, O.N.; Strelets, V.V.

1983-09-01

324

Determination of the free energy of adsorption on carbon blacks of a nonionic surfactant from aqueous solutions  

SciTech Connect

The adsorption of a nonionic surfactant (Triton X-100) from aqueous solutions has been studied on six carbon blacks with very different specific surface areas. The surface area occupied per surfactant molecule on the carbon black surface and the free energy of adsorption have been evaluated from the adsorption isotherms. Also, the free energy of adsorption has been determined from the free energy of interaction between adsorbent and adsorbate through water. The results obtained from both methods are in good agreement. They indicate that adsorption progresses following two different processes: the first one deals with the direct interaction between carbon black surface and adsorbate molecules, and the second one mainly due to the interaction between surfactant molecules at the adsorbent-solution interphase.

Gonzalez-Garcia, C.M.; Gonzalez-Martin, M.L.; Gomez-Serrano, V.; Bruque, J.M.; Labajos-Broncano, L.

2000-04-18

325

Calcium-magnesium carbonate solid solutions from Holocene conglomerate cements and travertines in the Coast Range of California  

USGS Publications Warehouse

Two calcium-magnesium carbonate solid solutions form Holocene travertines and conglomerate cements in fresh water stream channels of the Coast Range of California. Calcite does not yield the {015} diffraction maximum. The {006} diffraction maximum is lacking over most of the range of composition of calcite. Calcite has compositions from CaCO3 to Ca0.5Mg0.5CO3. Dolomite yields both the {006} and {015} diffraction maxima over its entire composition range, Ca0.6Mg0.4CO3 to Ca0.5Mg0.5CO3. The Ca-Mg carbonates form in isotopic equilibrium and thermodynamic disequilibrium from dispersion of Ca2+-rich water into CO32--rich water within the alluvium. The stable isotope data suggest that all the Mg-rich carbonates are primary precipitates and not a result of Mg-substitution in precursor CaCO3. There is a correlation between ??C13 and Mg content of the carbonates which predicts a 5%. fractionation of C13 between dolomite and calcite at sedimentary temperatures. C14 is incorporated in Ca-Mg carbonates forming from C13-poor meteoric waters and C13-rich waters from Cretaceous sediments. C14 ages of the Ca-Mg carbonates are apparent, and cannot be corrected to absolute values. Solution rates of calcite decrease with increasing MgCO3 content; dolomite dissolves slower than any calcite. ?? 1971.

Barnes, I.; O'Neil, J. R.

1971-01-01

326

Study of benzotriazole as corrosion inhibitors of carbon steel in chloride solution containing hydrogen sulfide using electrochemical impedance spectroscopy (EIS)  

NASA Astrophysics Data System (ADS)

Corrosion and inhibition studies on API 5LX65 carbon steel in chloride solution containing various concentrations of benzotriazole has been conducted at temperature of 70°C using Electrochemical Impedance Spectroscopy (EIS). Corroded carbon steel surface with and without inhibitor have been observed using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Energy Dispersive Spectroscopy (EDS). The objectives of this research are to study the performance of benzotriazole as corrosion inhibitors. The experimental results of carbon steel corrosion in 3.5% NaCl solution containing 500 mg/l H2S at different BTAH concentrations showed that corrosion rate of carbon steel decreases with increasing of BTAH concentrations from 0 to 10 mmol/l. The inhibition efficiency of BTAH was found to be affected by its concentration. The optimum efficiency obtained of BTAH is 93% at concentration of 5 mmol/l. The result of XRD and EDS analysis reveal the iron sulfide (FeS) formation on corroded carbon steel surface without inhibitor. The EDS spectrum show the Nitrogen (N) bond on carbon steel surface inhibited by BTAH.

Solehudin, Agus; Nurdin, Isdiriayani

2014-03-01

327

Biomass waste-derived activated carbon for the removal of arsenic and manganese ions from aqueous solutions  

NASA Astrophysics Data System (ADS)

The goal of this study is to investigate the preparation of low-cost activated carbon from bean pods waste and to explore their potential application for the removal of heavy metals from aqueous solutions. Conventional physical (water vapor) activation was used for synthesizing the adsorbent. The obtained carbon was employed for the removal of As (III) and Mn (II) from aqueous solutions at different initial concentrations and pH values. Adsorption for both ions follows Langmuir-type isotherm, the maximum loading capacities for arsenic (III) and Mn (II) ions being 1.01 and 23.4 mg g -1, respectively. According to the experimental data, it can be inferred that the basic character of the surface, i.e. the high content of basic groups, favors adsorption of ions. Arsenic adsorption capacity on the carbon obtained from agricultural waste was found to be similar to this of more expensive commercial carbons showing high adsorption capability. Regarding manganese adsorption, herein obtained carbon presented higher uptake adsorption than that of activated carbons reported in the literature.

Budinova, T.; Savova, D.; Tsyntsarski, B.; Ania, C. O.; Cabal, B.; Parra, J. B.; Petrov, N.

2009-02-01

328

Characterization of atomic structure of oxide films on carbon steel in simulated concrete pore solutions using EELS  

NASA Astrophysics Data System (ADS)

The atomic structure of oxide films formed on carbon steel that are exposed to highly alkaline simulated concrete pore solutions was investigated using Electron Energy Loss Spectroscopy (EELS). In particular, the effect of chloride exposure on film structure was studied in two types of simulated pore solutions: saturated calcium hydroxide (CH) and a solution prepared to represent typical concrete pore solutions (CP). It was shown that the films that form on carbon steel in simulated concrete pore solutions contained three indistinct layers. The inner oxide film had a structure similar to that of FeIIO, which is known to be unstable in the presence of chlorides. The outer oxide film mainly resembled Fe3O4 (FeIIO·Fe2IIIO3) in the CH solution and ?-Fe2IIIO3/Fe3O4 in the CP solution. The composition of the transition layer between the inner and outer layers of the oxide film was mainly composed of Fe3O4 (FeIIO·Fe2IIIO3). In the presence of chloride, the relative amount of the FeIII/FeII increased, confirming that chlorides induce valence state transformation of oxides from FeII to FeIII, and the difference between the atomic structures of oxide film layers diminished.

Gunay, H. Burak; Ghods, Pouria; Isgor, O. Burkan; Carpenter, Graham J. C.; Wu, Xiaohua

2013-06-01

329

Breadboard wash water renovation system. [using ferric chloride and ion exchange resins to remove soap and dissolved salts  

NASA Technical Reports Server (NTRS)

A total wash water renovation system concept was developed for removing objectionable materials from spacecraft wash water in order to make the water reusable. The breadboard model system described provides for pretreatment with ferric chloride to remove soap by chemical precipitation, carbon adsorption to remove trace dissolved organics, and ion exchange for removal of dissolved salts. The entire system was put into continuous operation and carefully monitored to assess overall efficiency and equipment maintenance problems that could be expected in actual use. In addition, the capacity of the carbon adsorbers and the ion-exchange resin was calculated and taken into consideration in the final evaluation of the system adequacy. The product water produced was well within the Tentative Wash Water Standards with regard to total organic carbon, conductivity, urea content, sodium chloride content, color, odor, and clarity.

1978-01-01

330

Electrodialysis of calcium and carbonate high concentration solutions and impact on composition in cations of membrane fouling.  

PubMed

Fouling, which is the accumulation of undesired solid materials at the phase interfaces of permselective membranes, is one of the major problems in electrodialysis. The objectives of the present work were to investigate the effect of the composition in calcium and carbonate of a model solution to be treated by conventional electrodialysis on their migration kinetics and the composition in cations of the membrane fouling. In the absence of sodium carbonate in the solution, no fouling was visually observed on anion-exchange membranes (AEM) and fouling was observed only at 1600 mg/L CaCl2 on cation-exchange membrane (CEM), while at only 800 mg/L CaCl2 with sodium carbonate, a deposit was observed on both membranes. This difference could be explained by the fact that carbonate has a high buffer capacity, and the time to reach pH 4.0 was then longer than the one without carbonate. Consequently, the migration of the ionic species was carried out over a longer period of time during ED treatment with sodium carbonate addition and in extent the demineralization rates were higher: 43 vs 86%. For treatment with sodium carbonate and 1600 mg/L CaCl2, the higher migration during ED treatment, increased the concentration of calcium, from 14.24 to 93.38 mg/g dry membrane and from 0.74 to 10.27 mg/g dry membrane for CEM and AEM, respectively. Due to the basic pH on the side of the membrane in contact with the NaCl solution, the calcium would precipitate to form calcium hydroxide on CEM while the calcium migrated through the CEM was blocked by the AEM where it formed another fouling. PMID:15897083

Bazinet, Laurent; Araya-Farias, Monica

2005-06-15

331

Accelerated carbonation of Friedel's salt in calcium aluminate cement paste  

SciTech Connect

The stability of Friedel's salt with respect to carbonation has been studied in calcium aluminate cement (CAC) pastes containing NaCl (3% of Cl{sup -} by weight of cement). Carbonation was carried out on a powdered sample in flowing 5% CO{sub 2} gas at 65% relative humidity to accelerate the process. At an intermediate carbonation step, a part of the sample was washed and dried up to 10 cycles to simulate a dynamic leaching attack. The two processes were followed by means of X-ray diffraction (XRD), pH and Cl{sup -} analyses in the simulated pore solution.

Goni, S.; Guerrero, A

2003-01-01

332

Pyrite oxidation in carbonate-buffered solution: 2. Rate control by oxide coatings  

NASA Astrophysics Data System (ADS)

The kinetic behaviour of pyrite oxidation in the laboratory was studied over a period of about 10,000 hours in reactors through which a carbonate-buffered solution and air (20% O 2) flowed continuously. Three grain size fractions were monitored. The concentration of sulphate and the mass of the effluent solution were measured periodically to calculate oxidation rates. The results indicate that the rates of reaction decreased significantly with time. The rates initially exhibited an inverse dependence on grain size (within 400 h) then became more linear with the square of the inverse grain size at later times (after 8000 h) suggesting a surface-layer control of the reaction with time. Surface analysis by X-ray Photoelectron Spectroscopy revealed the presence of ferric oxide on the pyrite surfaces, and ion boring with auger electron spectroscopy indicated a layer thickness on the order of 0.6 microns on the 215 micron grains. The data are represented by a shrinking core model which includes the effects of the surface rate constant plus the diffusive resistance to oxygen transfer through the accumulating reaction layer as oxidation proceeds. The three grain sizes (representing different specific surface areas) exhibited consistent estimates of the surface rate constant ( Ks = 3.07 × 10 -6mh-1 ± 46%) and the diffusion coefficient for oxygen through the oxide layer ( Ds = 1.08 × 10 -12m2h-1 ± 30%). The estimated thickness of the oxide layer at the end of the experiment agreed well with the measured value. Oxide accumulation on the pyrite surfaces under neutral pH conditions results in a significant reduction in oxidation rates over time. This behaviour has important implications for the reduction of the rate of release of oxidation products, including hydrogen ions, to environments where sulphide mineral wastes are exposed to the atmosphere.

Nicholson, R. V.; Gillham, R. W.; Reardon, E. J.

1990-02-01

333

Metallocoenzyme-mediated reductive transformation of carbon tetrachloride in titanium (III) citrate aqueous solution  

SciTech Connect

Transformation pathways for carbon tetrachloride (CCl{sub 4}) catalyzed by hematin or vitamin B{sub 12} in aqueous titanium(III) citrate solution are proposed. The reaction of CCl{sub 4} with B{sub 12} was zero order in CCl{sub 4} and first order in B{sub 12}, and the rate constant was measured from pH 7.3 to pH 10.3. The proposed rate-limiting step is the reduction of the stable trichloromethylcobalamin (CCl{sub 3}-Cbl) intermediate by titanium(III) citrate at alkaline pH and the sterically induced CCl{sub 3}-Cbl decomposition at neutral pH. The reaction kinetics can be described by a modified Michaelis-Menten model in the saturated regime. With hematin, only the pseudo-first-order rate constant was determined due to the significant deactivation of the coenzyme. The turnover number of hematin (molecules of CCl{sub 4} transformed/molecule of hematin deactivated) was 27 at pH 8.0 and 42 at pH 9.9. Vitamin B{sub 12} was a more stable and more effective catalyst (on a molar basis) than hematin with respect to CCl{sub 4}. Chloroform (CHCl{sub 3}) was the primary product in titanium(III) citrate solution, and the yield was a function of pH, Ti(III) concentration, and organic content regardless of whether a coenzyme was present or which coenzyme was used. Although B{sub 12} and hematin can both enhance the CCl{sub 4} transformation rate, they have little effect on the CHCl{sub 3} yield. Titanium(III) citrate, on the other hand, controls not only the transformation rate but also CHCl{sub 3} formation. 77 refs., 10 figs.

Chiu, P.C.; Reinhard, M. [Stanford Univ., CA (United States)

1995-03-01

334

Inhibiting properties and adsorption of an amine based fatty acid corrosion inhibitor on carbon steel in aqueous carbon dioxide solutions.  

National Technical Information Service (NTIS)

Carbon dioxide corrosion is a major corrosion problem in oil and gas production systems and many organic inhibitors have been tested and used to protect the substrate from corrosion. This thesis studies the mechanism of interaction of the inhibitor molecu...

J. Buchweishaija

1997-01-01

335

Mechanisms controlling the production and transport of methane, carbon dioxide, and dissolved solutes within a boreal peatland  

SciTech Connect

Peatlands are one of the most important terrestrial reservoirs in the global cycle for carbon, and are a major source for atmospheric methane. However, little is known about the dynamics of these carbon reservoirs or their feedback mechanisms with the pool of atmospheric CO{sub 2} during the Holocene. Specifically, it is unknown whether large peat basins are sources, sinks, or steady-state reservoirs for the global carbon cycle. In particular, the production and transport of methane, carbon dioxide, and dissolved organic carbon form the deeper portions of these peatlands is unknown. Our DOE research program is to conduct an integrated ecologic and hydrogeochemical study of the Glacial Lake Agassiz peatlands (northern Minnesota) to better understand the carbon dynamics in globally significant peat basins. Specifically, our study will provide local and regional data on (1), rates of carbon accumulation and loss and fluxes of methane in the peat profiles; (2) the physical and botanical factors controlling the production of methane and carbon dioxide in the wetland; and (3) the role of hydrogeologic processes in controlling the fluxes of gases and solutes through the peat. We intend to use computer simulation models, calibrated to field data, to scale-up from local to regional estimates of methane and carbon dioxide within the basin. How gases and dissolved organic carbon escapes form peatlands in unknown. It has been suggested that the concentrations of methane produced in the upper peat are sufficient to produce diffusion gradients towards the surface. Alternatively, gas may move through the peat profile by groundwater advection.

Siegel, D.I.

1992-04-09

336

Deintercalation of carbonate ions from carbonate-type layered double hydroxides (LDHs) using acid–alcohol mixed solutions  

Microsoft Academic Search

Because of the high affinity of carbonate ions (CO32?) for LDHs (layered double hydroxides), their decarbonation—deintercalation of carbonate ions and conversion into LDHs containing other anions—has been considered difficult. So far, dilute acids have been used for decarbonation with additional salt to enhance the reaction. We found that the acid resistance of the LDHs is much higher in alcohols such

Nobuo Iyi; Hirohisa Yamada; Takayoshi Sasaki

2011-01-01

337

Assessment and optimization of an ultrasound-assisted washing process using organic solvents for polychlorinated biphenyl-contaminated soil.  

PubMed

The goal of this work was to evaluate a washing process that uses organic solutions for polychlorinated biphenyl (PCB)-contaminated soil, and includes an ultrasound pre-treatment step to reduce operational times and organic solvent losses. In a preliminary trial, the suitability of 10 washing solutions of different polarities were tested, from which three n-hexane-based solutions were selected for further evaluation. A second set of experiments was designed using a three-level Taguchi L27 orthogonal array to model the desorption processes of seven different PCB congeners in terms of the variability of their PCB concentration levels, polarity of the washing solution, sonication time, the ratio washing solution/soil, number of extraction steps and total washing time. Linear models were developed for the desorption processes of all congeners. These models provide a good fit with the results obtained. Moreover, statistically significant outcomes were achieved from the analysis of variance tests carried out. It was determined that sonication time and ratio of washing solution/soil were the most influential process parameters. For this reason they were studied in a third set of experiments, constructed as a full factorial design. The process was eventually optimized, achieving desorption rates of more than 90% for all congeners, thus obtaining concentrations lower than 5 ppb in all cases. The use of an ultrasound-assisted soil washing process for PCB-contaminated soils that uses organic solvents seems therefore to be a viable option, especially with the incorporation of an extra step in the sonication process relating to temperature control, which is intended to prevent the loss of the lighter congeners. PMID:23771880

Bezama, Alberto; Flores, Alejandra; Araneda, Alberto; Barra, Ricardo; Pereira, Eduardo; Hernández, Víctor; Moya, Heriberto; Konrad, Odorico; Quiroz, Roberto

2013-10-01

338

Activity and stability of immobilized carbonic anhydrase for promoting CO2 absorption into a carbonate solution for post-combustion CO2 capture.  

PubMed

An Integrated Vacuum Carbonate Absorption Process (IVCAP) currently under development could significantly reduce the energy consumed when capturing CO2 from the flue gases of coal-fired power plants. The biocatalyst carbonic anhydrase (CA) has been found to effectively promote the absorption of CO2 into the potassium carbonate solution that would be used in the IVCAP. Two CA enzymes were immobilized onto three selected support materials having different pore structures. The thermal stability of the immobilized CA enzymes was significantly greater than their free counterparts. For example, the immobilized enzymes retained at least 60% of their initial activities after 90 days at 50 °C compared to about 30% for their free counterparts under the same conditions. The immobilized CA also had significantly improved resistance to concentrations of sulfate (0.4 M), nitrate (0.05 M) and chloride (0.3 M) typically found in flue gas scrubbing liquids than their free counterparts. PMID:21974883

Zhang, Shihan; Zhang, Zhaohui; Lu, Yongqi; Rostam-Abadi, Massoud; Jones, Andrew

2011-11-01

339

Carbon Solution in Core-Forming Magma Ocean Conditions: Implications for the Origin and Distribution of Terrestrial Carbon  

NASA Astrophysics Data System (ADS)

The origin of bulk silicate Earth carbon inventory is poorly known and the fate of the element during the early Earth differentiation and core formation is a missing link in the evolution of the terrestrial carbon cycle. Here we present high pressure-temperature experiments that simulate metal-silicate equilibria in a shallow magma ocean. Experiments were performed at 1-5 GPa, 1600-2100 °C on mixtures of synthetic or natural silicates (tholeiitic basalt/ alkali basalt/ komatiite/ fertile peridotite) and Fe-Ni-C±Co±S contained in graphite or MgO capsules. All the experiments produced immiscible Fe-rich metallic and silicate melts at oxygen fugacity (fO2) between ~IW-1.5 and IW-1.9. Carbon and hydrogen concentrations of basaltic glasses and non-glassy quenched silicate melts were determined using secondary ionization mass spectrometry (SIMS) and speciation of dissolved C-O-H volatiles in silicate glasses was constrained using Raman spectroscopy. Carbon contents of metallic melts were determined using both electron microprobe and SIMS. Our experiments indicate that at core-forming, reduced conditions, carbon in mafic-ultramafic magmas dissolves primarily as various hydrogenated species and the total carbon storage capacity, although is significantly higher than solubility of CO2 under similar conditions, remains low (<500 ppm). The total carbon content in our reduced melts at graphite saturation increases with increasing melt depolymerization (NBO/T), consistent with recent spectroscopic studies [1], and modestly with increasing hydration. Carbon behaves as a metal loving element during core-mantle separation and metal/silicate carbon partition coefficient, DC varies between ~3500 and ?150 and increases with increasing pressure and decreases with increasing temperature and melt NBO/T. Extrapolation of our data to the plausible conditions of core-mantle equilibration suggest that if only a trace amount of carbon (~730 ppm C; [2]) was available during early Earth differentiation, most of it was partitioned to the core (with 0.20-0.25 wt.% C) and no more than ~10-30% of the present-day mantle carbon budget (50-200 ppm CO2) could be derived from a magma ocean residual to core formation. With equilibrium core formation removing most of the carbon initially retained in the terrestrial magma ocean, explanation of the modern bulk silicate Earth carbon inventory requires a later replenishment mechanism. Partial entrapment of metal melt in solid silicate matrix, carbon ingassing by magma ocean-atmosphere interaction, and carbon outgassing from the core aided by reaction of core metal and deeply subducted water are some of the viable mechanisms. [1] Mysen et al. (2009), GCA 73, 1696-1710. [2] McDonough (2003), The Mantle and Core, Treatise of Geochemistry, 547-568.

Dasgupta, R.; Chi, H.; Walker, D.; Shimizu, N.; Buono, A. S.

2012-12-01

340

Contact angles of diiodomethane on silicon-doped diamond-like carbon coatings in electrolyte solutions.  

PubMed

The influence of surrounding electrolyte type and concentration on the contact angle of hydrophobic diiodomethane on silicon-doped diamond-like carbon (DLC) coatings was examined to provide insight into how the presence of electrolytes in the solution influences adhesion of hydrophobic material to doped DLC surfaces. There was a small but statistically significant increase of contact angle with increasing electrolyte concentration over the range from 0 to approximately 0.01 M, after which the contact angle was virtually unaffected by further increase in the concentration of electrolyte. It was shown that CaCl(2) has a stronger influence on the change of the contact angle than NaCl, and that an increase in Si content in the DLC coatings increased the change in the contact angle of diiodomethane for all types of electrolyte. These observations suggest that the adhesion to the Si-doped DLC surfaces is reduced by addition of the electrolytes to the surrounding solvent. This could be explained by increased ion adsorption on the DLC surface with increase in silicon doping, causing the surfaces to be more hydrophilic. PMID:18657820

Borisenko, Konstantin B; Evangelou, Evangelos A; Zhao, Qi; Abel, Eric W

2008-10-15

341

Characteristics of cesium ion sorption from aqueous solution on bentonite- and carbon nanotube-based composites.  

PubMed

The technology development of Cs(+) capture from aqueous solution is crucial for the disposal of nuclear waste and still remains a significant challenge. Previous researches have been proven that ion exchanges with the cations and hydroxyl exchange are the main sorption mechanisms for Cs(+). Therefore, how important are the cation exchange and the hydroxyl exchange mechanisms to Cs(+) sorption? And whether can we improve the sorption capacity of the material by increasing the amount of hydroxyl groups? With these in mind, we herein designed the chitosan-grafted carbon nanotubes (CS-g-CNTs) and the chitosan-grafted bentonite (CS-g-bentonite) by plasma-induced grafting method. The interactions of Cs(+) with CNTs, bentonite, CS-g-CNTs and CS-g-bentonite composites were investigated. The sorption of Cs(+) is mainly dominated by strong cation exchange in monovalent Group I and divalent Group II. And the cation-exchange mechanism is much more effective than the hydroxyl group exchange. The effect of hydroxyl groups is dependent on the property of the matrix. We cannot improve the Cs adsorption capacity of material for Cs(+) only by increasing the amount of hydroxyl groups in any case. The spatial structure and the cation-exchange capacity of the material are important factors for choosing the sorbent for Cs(+) removal from radioactive waste water. PMID:24762700

Yang, Shubin; Han, Cho; Wang, Xiangke; Nagatsu, Masaaki

2014-06-15

342

Removal of boron from aqueous solution using magnetic carbon nanotube improved with tartaric acid  

PubMed Central

Boron removal capacity of multi-walled carbon nanotubes (MWCNTs) modified with tartaric acid was investigated in this study. Modification of MWCNTs with tartaric acid was confirmed by Boehm surface chemistry method and fourier transform infra-red (FT-IR) spectroscopy. Experiments were performed to determine the adsorption isotherm and adsorption thermodynamic parameters of boron adsorption on tartaric acid modified MWCNTs (TA-MWCNTs). The effect of variables including initial pH, dosage of adsorbent, contact time and temperature was investigated. Analysis of data showed that adsorption equilibrium could be better described by Freundlich isotherm and the maximum adsorption capacities obtained at the pH of 6.0 was 1.97 mg/g. The estimated thermodynamic values of free energy (?G°), entropy (?S°) and enthalpy (?H°) indicated a spontaneous and an endothermic process. Furthermore, the TA-MWCNTs was magnetized for separation of boron-contaminated adsorbent from aqueous solution by applying magnetic field. The results showed that magnetic TA-MWCNTs particles were separated effectively after adsorption from contaminated water.

2014-01-01

343

Single-walled carbon nanotubes/polymer composite electrodes patterned directly from solution.  

PubMed

This work describes a simple technique for direct patterning of single-walled carbon nanotube (SWNT)/poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) composite electrodes in a large area on a substrate based on the solution transfer process by microcontact printing using poly(dimethylsiloxane) (PDMS) stamps. Various shapes of SWNT/PEDOT-PSS composite patterns, such as line, circle, and square, can be easily fabricated with high pattern fidelity and structural integrity. The single parallel line pattern device exhibits high electrical conductivity (0.75 × 10(5) S/m) and electronic stability because of alignment of nanotubes and big-size SWNT bundles (?5 nm). The electromechanical study reveals that the composite patterns show ?1% resistance change along SWNT alignment direction and ?5% resistance change along vertical alignment direction after 200 bend cycles. Our approach provides a facile, low-cost method to pattern transparent conductive SWNT/polymer composite electrodes and demonstrates a novel platform for future integration of conducting SWNT/polymer composite patterns for optoelectronic applications. PMID:21557548

Chang, Jingbo; Najeeb, Choolakadavil Khalid; Lee, Jae-Hyeok; Kim, Jae-Ho

2011-06-01

344

2-chlorophenol sorption from aqueous solution using granular activated carbon and polymeric adsorbents  

NASA Astrophysics Data System (ADS)

Adsorption equilibrium and kinetics of 2-chlorophenol (2-CP) one of the chlorophenols (CPs) onto bituminous coal based Filtrasorb-400 grade granular activated carbon and three different types of polymeric adsorbents were studied in aqueous solution in a batch system. Langmuir isotherm models were applied to experimental equilibrium data of 2-CP adsorption. Equilibrium data fitted very well to the Langmuir equilibrium models of 2-CP. Adsorbent monolayer capacity Q Langmuir constant b and adsorption rate constants k a were evaluated. 2-CP adsorption using GAC is very rapid in the first hour of contact where 70-80% of the adsorbate is removed by GAC followed by a slow approach to equilibrium. Whereas in case of polymeric adsorbents 60-65% of the adsorbate is removed in the first 30 min which is then followed by a slow approach to equilibrium. The order of adsorption of 2-CP on different adsorbents used in the study is found to be in following order: F-400 > XAD-1180 > XAD-4 > XAD-7HP.

Ghatbandhe, A. S.; Jahagirdar, H. G.; Yenkie, M. K. N.; Deosarkar, S. D.

2013-08-01

345

Removal of boron from aqueous solution using magnetic carbon nanotube improved with tartaric acid.  

PubMed

Boron removal capacity of multi-walled carbon nanotubes (MWCNTs) modified with tartaric acid was investigated in this study. Modification of MWCNTs with tartaric acid was confirmed by Boehm surface chemistry method and fourier transform infra-red (FT-IR) spectroscopy. Experiments were performed to determine the adsorption isotherm and adsorption thermodynamic parameters of boron adsorption on tartaric acid modified MWCNTs (TA-MWCNTs). The effect of variables including initial pH, dosage of adsorbent, contact time and temperature was investigated. Analysis of data showed that adsorption equilibrium could be better described by Freundlich isotherm and the maximum adsorption capacities obtained at the pH of 6.0 was 1.97 mg/g. The estimated thermodynamic values of free energy (?G°), entropy (?S°) and enthalpy (?H°) indicated a spontaneous and an endothermic process. Furthermore, the TA-MWCNTs was magnetized for separation of boron-contaminated adsorbent from aqueous solution by applying magnetic field. The results showed that magnetic TA-MWCNTs particles were separated effectively after adsorption from contaminated water. PMID:24393401

Zohdi, Nima; Mahdavi, Fariba; Abdullah, Luqman Chuah; Choong, Thomas Sy

2014-01-01

346

Determination of carbon-centered radicals in aqueous solution by liquid chromatography with fluorescence detection  

SciTech Connect

A simple method to detect subnanomolar to micromolar levels of photochemically generated carbon-centered radicals in aqueous solutions has been developed and optimized. This method is based on the efficient trapping of radicals by a water-soluble amino nitroxide, followed by derivatization of the trapped products with fluorescamine to produce highly fluorescent adducts. These adducts can be separated by reversed-phase high-performance liquid chromatography and detected fluorometrically. The fluorescent derivatives are stable over a period of days. The detection limit, primarily determined by reagent interferences, ranged from 0.3 to 1 nM per analyte for a 500-{mu}L injection at a signal-to-noise ratio of two. The precision of the method for the determination of adduct concentrations in the 1-10 nM range varied from 2.4 to 8.4% relative standard deviation (n = 6). A direct comparison with electron paramagnetic resonance spectroscopy/spin trapping illustrates the advantages of our technique. One important feature of the method is that it permits the simultaneous detection of an array of radicals, as demonstrated through the study of the photochemical production of radicals in a variety of natural water samples and in Suwanee River fulvic acid.

Kieber, D.J.; Blough, N.V. (Woods Hole Oceanographic Institution, MA (USA))

1990-11-01

347

Reactivity of Hontomín carbonate rocks to acidic solution injection: reactive "push-pull" tracer tests results  

NASA Astrophysics Data System (ADS)

Several field tests will be carried out in order to characterize the reservoir for CO2 injection in Hontomín (Burgos, Spain) as part of the Compostilla project of "Fundación Ciudad de la Energía" (CIUDEN). Once injected, the dissolution of the CO2 in the resident brine will increase the acidity of the water and lead to the dissolution of the rocks, constituted mainly by carbonates. This mechanism will cause changes in the aquifer properties such as porosity and permeability. To reproduce the effect of the CO2 injection, a reactive solution with 2% of acetic acid is going to be injected in the reservoir and extracted from the same well (reactive "push-pull" tracer tests) to identify and quantify the geochemical reactions occurring into the aquifer. The reactivity of the rock will allow us also to evaluate the changes of its properties. Previously, theoretical calculations of Damkhöler numbers were done to determine the acid concentrations and injection flow rates needed to generate ramified-wormholes patterns, during theses "push-pull" experiments. The aim of this work is to present the results and a preliminary interpretation of the field tests.

De Gaspari, Francesca; Cabeza, Yoar; Luquot, Linda; Rötting, Tobias; Saaltink, Maarten W.; Carrera, Jesus

2014-05-01

348

Washing and alkaline leaching of Hanford tank sludges: A status report  

SciTech Connect

Because of the assumed high cost of high-level waste (HLW) immobilization and disposal, pretreatment methods are being developed to minimize the volume of HLW requiring vitrification. Pacific Northwest Laboratory (PNL) is investigating several options for pretreating the radioactive wastes stored in underground tanks at the Hanford Site. The pretreatment methods under study for the tank sludges include: (1) simply washing the sludges with dilute NaOH, (2) performing caustic leaching (as well as washing) to remove certain wash components, and (3) dissolving the sludges in acid and extracting key radionuclides from the dissolved sludge solutions. The data collected in this effort will be used to support the March 1998 decision on the extent of pretreatment to be performed on the Hanford tank sludges. This document describes sludge washing and caustic leaching tests conducted in FY 1994. These tests were performed using sludges from single-shell tanks (SST) B-201 and U-110. A summary is given of all the sludge washing and caustic leaching studies conducted at PNL in the last few years.

Lumetta, G.J.; Rapko, B.M.

1994-09-01

349

Detection and determination of solute carbon in grain interior to correlate with the overall carbon content and grain size in ultra-low-carbon steel.  

PubMed

In this study, every effort was exerted to determine and accumulate data to correlate microstructural and compositional elements in ultra-low-carbon (ULC) steels to variation of carbon content (12-44 ppm), manganese (0.18-0.36%), and sulfur (0.0066-0.001%). Quantitative analysis of the ULC steel using optical microscope, scanning electron microscope, transmission electron microscope, and three-dimensional atom probe revealed the decrease of grain size and dislocation density with the increase of carbon contents and/or increase of the final delivery temperature. For a given carbon content, the grain interior carbon concentration increases as the grain size increases. PMID:23920177

Dong, Jiling; He, Yinsheng; Lee, Chan-Gyu; Lee, Byungho; Yoon, Jeongbong; Shin, Keesam

2013-08-01

350

Washing Away Bioprocessing Cost: Pressurized Hot Wash Improves Cellulosic Ethanol Technology  

SciTech Connect

Thermochemical pretreatment is a key step in biotechnology for converting lignocellulosic biomass to fuel ethanol and other valuable chemicals. U.S. Department of Energy Biofuels Program researchers have found that adding a Pressurized Hot Wash (PHW) step immediately following pretreatment--while the pretreated material is still at high temperature and pressure--significantly improves the overall process. The ''hot-washed'' pretreated material can be more efficiently digested by cellulase enzymes. Additionally, soluble lignins with potentially valuable unique reactive properties are separated out.

Not Available

2002-09-01

351

Hand washing practices in a college town environment.  

PubMed

Many people do not wash their hands when the behavior in which they engage would warrant it. Most research of hand washing practices to date has taken place in high-traffic environments such as airports and public attraction venues. These studies have established a persistent shortcoming and a gender difference in hand washing compliance. Using field observations of 3,749 people in a college town environment, the research described in this article replicates and extends earlier work while identifying potential environmental and demographic predictors of hand washing compliance. Additionally, the authors' research suggests that proper hand washing practices, as recommended by the Centers for Disease Control and Prevention, are not being practiced. Finally, the authors' research raises a question as to the accuracy of earlier measurements of "proper" hand washing practices, suggesting that compliance rates are inflated. The results can help increase hand washing rates for the general public and thus decrease the risk of transmitting disease. PMID:23621052

Borchgrevink, Carl P; Cha, JaeMin; Kim, SeungHyun

2013-04-01

352

Filtration, Washing, and Caustic Leaching of Hanford Tank AZ-101 Sludge  

SciTech Connect

The world’s largest vitrification facility is being designed and constructed at the U.S. Department of Energy’s Hanford Site, near Richland, Washington to convert radioactive waste stored in underground tanks into glass. Flow sheets call for washing and caustic leaching to pretreat the Hanford Envelope D sludge before it undergoes high-level waste (HLW) vitrification. These pretreatment steps reduce the quantity of HLW generated, by removing components that are soluble in water or caustic solutions, and often limit the waste loading in the glass. Crossflow filtration is specified to separate the wash and leach solutions from the solids. In crossflow filtration, the majority of the filter cake is swept away by the fluid flowing across it. Approximately 4313 g of slurry from Hanford Tank AZ-101 were evaluated by the pretreatment processes of crossflow filtration, washing, caustic leaching, and rinsing. The filterability was measured with a 0.1-mm sintered metal filter using a single-element, crossflow filtration system. Permeate flux of the as-received and washed slurries decayed linearly with the log of the undissolved solids concentration. The permeate flux of these slurries was also shown to be inversely proportional to the permeate viscosity. Statistical analysis indicated that the permeate flux of an 8-wt% insoluble solids slurry was also dependent on transmembrane pressure. As the slurry was concentrated to 18-wt%, the flux was dependent on axial velocity, with little dependency on transmembrane pressure. Samples of permeate from each wash were analyzed for chemical and radiochemical constituents. Primary component removal during the washing and leaching steps are discussed. This work provides important confirmation that the pretreatment of Hanford Envelope D wastes will have acceptable filterability and component removal during the pretreatment steps specified.

Geeting, John GH; Hallen, Richard T.

2005-02-15

353

Adsorption of Zn(II) and Cd(II) ions onto magnesium and activated carbon composite in aqueous solution  

NASA Astrophysics Data System (ADS)

Magnesium and coconuts shell activated carbon composite was prepared to selectively remove heavy metals ions in aqueous solution. Zinc(II) and cadmium(II) ions were used to clarify the adsorption capacity of the composite in comparison with no magnesium containing activated carbon. Influence of the initial heavy metal concentration, time course and solution temperature on the adsorption amounts were examined for the two adsorbents, and surface chemistry of the adsorbents was also characterized using Boehm titration. The magnesium composite adsorbed greater amount of Zn(II) and Cd(II) ions than the no magnesium counterpart. The adsorption amount of Cd(II) was not influenced with rise in solution temperature for the composite, whereas decrease in adsorption was observed for the counterpart. The loaded magnesium was estimated to be combined with carbon surface via oxygen bridge. Cadmium(II) was adsorbed onto the composite surface by ion exchange process with releasing equivalent amount of Mg(II) from the carbon surface, while Zn(II) would adsorb onto the composite by not only the ion exchange, but also the electrostatic interaction with the C? electrons on the graphite surface from the experimental results.

Yanagisawa, Hiroki; Matsumoto, Yuki; Machida, Motoi

2010-01-01

354

Effect of PWVA\\/Sb 2O 3 complex inhibitor on the corrosion behavior of carbon steel in 55%LiBr solution  

Microsoft Academic Search

The inhibition performance of PWVA\\/Sb2O3 complex inhibitor on carbon steel was studied in 55%LiBr+0.07molL?1 LiOH solution. Results indicated that the complex inhibitor decreased both anodic and cathodic polarization current density and widened the passive potential region of carbon steel in test solution and can be classified as mixed inhibitor. The complex inhibitor exhibited excellent inhibition performance on carbon steel when

Xianqi Hu; Chenghao Liang

2008-01-01

355

Influence of mesopore volume and adsorbate size on adsorption capacities of activated carbons in aqueous solutions  

Microsoft Academic Search

Liquid-phase adsorption of phenol, iodine and tannic acid onto commercial grade granular activated carbons and activated carbon fabric was conducted to explore the influence of the mesopore volume and the size of adsorbates on the adsorption capacity. These carbons have different mesopore volumes, while possessing similar surface areas and micropore volumes, which are believed to determine the adsorption capacity in

Chien-To Hsieh; Hsisheng Teng

2000-01-01

356

Prediction of equilibrium solubility of Carbon Dioxide in aqueous 2-amino-2-methyl-1,3-propanediol Solutions  

Microsoft Academic Search

The modified Kent-Eisenberg model was used to predict the solubility of carbon dioxide in aqueous 2-amino-2-methyl-1,3-propanediol\\u000a (AMPD) solutions over a wide range of solvent concentration (10-30 mass %), temperature (30-60 °C), and partial pressure of\\u000a carbon dioxide (5-1,100 kPa). For more accurate prediction, a new set of experimental data of this system was also presented\\u000a and used in model calculation.

Jeom-In Baek; Ji-Ho Yoon; Hee-Moon Eum

2000-01-01

357

Equilibrium hydrate formation conditions for hydrogen sulfide, carbon dioxide, and ethane in aqueous solutions of ethylene glycol and sodium chloride  

SciTech Connect

Natural gas components such as hydrogen sulfide, carbon dioxide, and ethane form gas hydrates of structure I under suitable temperature and pressure conditions. Information on such conditions is vital to the oil and gas industry in order to design and operate processing equipment and pipelines so that hydrate formation is avoided. Incipient equilibrium hydrate formation conditions for hydrogen sulfide, carbon dioxide, and ethane in aqueous solutions of ethylene glycol and sodium chloride were experimentally obtained in the temperature range 264--290 K and the pressure range 0.23--3.18 MPa. A variable-volume sapphire cell was used for the measurements.

Majumdar, A.; Mahmoodaghdam, E.; Bishnoi, P.R.

2000-02-01

358

Axial Dispersion during Hanford Saltcake Washing  

SciTech Connect

Clean up of Hanford salt cake wastes begins with dissolution retrieval of the sodium rich salts that make up the dominant majority of mass in the tanks. Water moving through the porous salt cake dissolves the soluble components and also displaces the soluble radionuclides (e.g. 137Cs and 99TcO4- ). The separation that occurs from this displacement, known as Selective dissolution, is an important component in Hanford’s pretreatment of low activity wastes for subsequent Supplemental treatment. This paper describes lab scale testing conducted to evaluate Selective dissolution of cesium from non-radioactive Hanford tank 241-S-112 salt cake simulant containing the primary chemicals found the the actual tank. An modified axial dispersion model with increasing axial dispersion was developed to predict cesium removal. The model recognizes that water dissolves the salt cake during washing, which causes an increase in the axial dispersion during the wash. This model was subsequently compared with on-line cesium measurements from the retrieval of tank 241-S-112. The model had remarkably good agreement with both the lab scale and full scale data.

Josephson, Gary B.; Geeting, John GH; Lessor, Delbert L.; Barton, William B.

2006-08-01

359

Effects of interstitial solute atoms on the very low strain-rate deformations for an IF steel and an ultra-low carbon steel  

Microsoft Academic Search

In order to investigate the effects of interstitial solute atoms on very low strain-rate deformation of steel by using an interstitial free (IF) steel and an ultra-low carbon (ULC) steel, creep tests and crosshead-arresting tests were conducted at room temperature. The concentrations of solute carbon and solute nitrogen for the ULC steel were 8 and 12 ppm, respectively, and were

N.. Tsuchida; E. Baba; K. Nagai; Y. Tomota

2005-01-01

360

Improving Hand-Washing Performance - A Crossover Study of Hand-Washing in the Orthopaedic Department  

PubMed Central

INTRODUCTION Effective hand-washing is essential for reducing the spread of infection in hospitals. We aimed to evaluate hand-washing performance of hospital personnel and to determine if this could be improved by education. MATERIALS AND METHODS A total of 55 personnel working in the orthopaedic department were asked to clean their hands using an alcohol gel containing a clear fluorescent substance. They were unaware of the assessment method. Performance was assessed by examining their hands under UV light to identify areas that had been neglected. Subjects could visualise which areas they had missed and were then educated regarding hand-washing technique and retested after 7 days. RESULTS Of the 55 subjects, 53 completed the study. Individual performance varied widely. Following a simple educational intervention, 49 out of 53 subjects improved from an average of 7.8% to 2.3% area missed (P < 0.001). CONCLUSIONS We suggest that hand-washing effectiveness needs to be improved and that a simple educational intervention can be effective.

Macdonald, Duncan JM; McKillop, Elisabeth CA; Trotter, Sylvia; Gray, Alastair JR

2006-01-01

361

Hand Washing in the Child Care Setting. When Should Hands Be Washed.  

National Technical Information Service (NTIS)

The product is a poster showing children how to wash their hands in order to reduce the spread of infections. The poster contains pictures and written explanations of proper handwashing steps. The poster lists the occasions when children and staff should ...

1994-01-01

362

Postharvest decay reduction of fig fruit (Ficus carica) by hot water sodium carbonate solutions dip.  

PubMed

Treatments as hot water dips or high temperature conditioning have been proven to be effective to control postharvest decay on various horticultural crops. These treatments reduce chilling injury and rot losses without causing detrimental effects on fruit firmness, flavour, taste or peel appearance. These technologies, aimed to control postharvest pathogens, can be easily matched with the use of "Generally Recognized as Safe" (G.R.A.S.) compounds and employed alternatively to pesticides, known to be harmful to health and environment. In this respect we studied the combined effect of sodium carbonate (SC) and hot water on the storability of black fig fruit cultivar 'Niedda Longa' of Sardinian germplasm. Second crop fig fruit, harvested in the middle of September, was dipped for one minute in water solutions containing 0, 0.05, 0.5, and 1% (w/v) of SC at 25 or 60 degrees C and then stored at 5 degrees C and 90% relative humidity (RH) for two weeks. After one and two weeks of storage decay, weight loss were monitored and visual assessment was scored. Treatments with hot solutions were more effective in controlling decay compared to cold ones and the best results were achieved with 0.5% of SC at 60 degrees C. This combination reduced the decay rate from 26% (control) to 0% after 1 week and from 50% to 14% after two weeks of storage, respectively. Lower or higher SC concentrations applied at 60 degrees C were less effective and, after two weeks of storage, decay percentages were 38 and 43.6%, respectively. Water dip at 60 degrees C did not affect the weight loss as compared to dips at 25 degrees C either after one or two weeks of storage. At the same time, a significant reduction was found only with 1% of SC at 25 degrees C. The fruit treated with 0.5% of SC at 60 degrees C also had the best visual assessment up to two weeks of storage. PMID:17390840

Molinu, M G; Venditti, T; Dore, A; D'Hallewin, G; Serusi, A; Del Caro, A; Agabbio, M

2006-01-01

363

Solid-Solute Phase Equilibria in Aqueous Solution. XI. Aqueous Solubility and Standard Gibbs Energy of Cadmium Carbonate  

Microsoft Academic Search

The solubilities of CdCO3 (otavite) in aqueous NaClO4 solutions have been investigated as a function of ionic strength (0.15 ? I\\/mol-kg?1 ? 5.35, 25°C) and temperature (25°C ? T ? 75°C, I = 1.00 mol-kg?1). A new Chemsage optimization routine was employed to simultaneously evaluate solubility data from this work and other sources, as well as standard electrode potentials determined

Heinz Gamsjäger; Wolfgang Preis; Erich Königsberger; M. Clara Magalhães; Paula Brandão

1999-01-01

364

Potential Use of Hyperoxygenated Solution as a Treatment Strategy for Carbon Monoxide Poisoning  

PubMed Central

Aim Carbon monoxide (CO) poisoning can cause permanent damage in tissues that are sensitive to hypoxia. We explored the feasibility and efficacy of using a hyperoxygenated solution (HOS) to treat severe acute CO poisoning in an animal model. Methods Male Sprague-Dawley rats were subjected to CO poisoning. The HOS was administered into the femoral vein of these rats through a catheter (10 ml/kg). Carboxyhemoglobin (COHb) and blood gases were used to assess the early damage caused by CO poisoning. S100? was measured to predict the development of late cognitive sequelae of CO. The Morris water maze test was performed to assess cognitive function, and Nissl staining was performed to observe histologic change. Results The COHb concentrations rapidly decreased at 5 min after the HOS administration; however, the PaO2 and SaO2 in rats treated with HOS increased significantly 5 min after the HOS administration. The S100? concentrations, which increased significantly after CO poisoning, increased at a much slower rate in the rats treated with HOS (HOS group) compared with the rats treated with O2 inhalation (O2 group). The escape latency in the place navigation test was shortened after CO poisoning on days 11-15 and days 26-30, and the swimming time in quadrant 4 in the spatial probe test on days 15 and 30 after CO poisoning was prolonged in the rats treated with HOS injection compared with the rats treated with oxygen inhalation or normal saline injection. The neuronal degeneration in the HOS group was alleviated than that in the CO or O2 group. Conclusion HOS efficiently alleviates the brain damage in acute CO-poisoned rats and thus may serve as a new way to treat human patients with CO poisoning in clinical practice.

Meng, Xiangzhong; Qi, Jian; Cui, Yuanyuan; Li, Yunqing; Zhang, Hui; Xu, Lixian

2013-01-01

365

A molecular dynamics study of structure and thermal properties of carbon dioxide in sodium chloride aqueous solution  

NASA Astrophysics Data System (ADS)

The structure and thermal conductivity of the sodium chloride (NaCl) aqueous solution in similar concentration to the seawater with saturated carbon dioxide (CO2) have been investigated by molecular dynamics simulation. The effects of pressure have been investigated under various pressures corresponding to the depth of the sea from 40m to 10000m. The negative pressure dependence of the thermal conductivity has been detected in the depth of more than 8000m, whereas that of NaCl aqueous solution without CO2 shows the positive pressure dependence.

Matsunaga, Shigeki

2014-03-01

366

Development and Performance Assessment of Soil Washing Equipment for Soil Contaminated with Radionuclide  

SciTech Connect

The purpose of this study is to develop a soil washing system and to define the most suitable experimental conditions for the individual elemental equipment in a soil washing system for decontaminating the radioactive soil from around a TRIGA (Training, Research, Isotope, General Atomic) reactor in Korea. Analysis results have shown that the main radionuclides were Cs{sup 137} and Co{sup 60}, the soil particle size ranges from 0.063 mm to 1.0 mm and the radioactive concentration was the strongest in a soil particle smaller than 0.063 mm as predicted. Meanwhile, an oxalic acid was found to be the most efficient chemical agent for washing, especially of cobalt. The scrubbing time of four hours was an optimum time to obtain a removal efficiency of more than 75% for {sup 137}Cs and {sup 60}Co. A mixing ratio of the soil weight to the volume of the oxalic acid solution, 1:10, was observed to be the best for a washing and it was estimated to be reasonable for 2 cycles of a scrubbing with 1.0 M of oxalic acid to avoid a generation of an excessive waste-solution. (authors)

Gye-Nam Kim; Jei-Kwon Moon; Chong-Hun Jung [Korea Atomic Energy Research Institute (Korea, Republic of)

2007-07-01

367

Impedance of Li?Sn, Li?Cd and Li?Sn?Cd alloys in propylene carbonate solution  

Microsoft Academic Search

Electric properties of passivating films forming on the surface of Li?Sn, Li?Cd and Li?Sn?Cd alloy electrodes in propylene carbonate-based solutions have been investigated using the electrode impedance spectroscopy technique. Within the range of high and medium frequencies, the impedance spectrum has been shown to be described by the equivalent circuit represented by geometric capacitance and ionic resistance of the film,

Alexei V. Churikov; Eugeny S. Nimon; Arlen L. Lvov

1997-01-01

368

Structural effects on the interactions of benzene and naphthalene sulfonates with activated carbon cloth during adsorption from aqueous solutions  

Microsoft Academic Search

Interactions of benzene and naphthalene sulfonates with activated carbon cloth (ACC) during adsorption from aqueous solutions were investigated. Systematically chosen sulfonates were sodium salt of benzene sulfonic acid (NaBS), disodium salt of 1,3-benzene disulfonic acid (Na2BDS), sodium salt of 1-naphthalene sulfonic acid (NaNS), disodium salt of 1,5-naphthalene disulfonic acid (Na2NDS) and trisodium salt of 1,3,(6 or 7)-naphthalene trisulfonic acid (Na3NTS).

Erol Ayranci; Osman Duman

2010-01-01

369

Adsorption of ?-picoline onto rice husk ash and granular activated carbon from aqueous solution: Equilibrium and thermodynamic study  

Microsoft Academic Search

In the present study, the batch adsorption experiments were carried out to calculate the adsorption capacities of rice husk ash (RHA) and commercial grade granular activated carbon (GAC) for the adsorption of ?-picoline (Pi) from aqueous solutions. The effect of various parameters like initial pH (pH0), adsorbent dose (m), contact time (t), initial concentration (C0) and temperature (T) on the

Dilip Hiradram Lataye; Indra Mani Mishra; Indra Deo Mall

2009-01-01

370

Electrochemical studies of the film formation on lithium in propylene carbonate solutions under open-circuit conditions  

SciTech Connect

The nature of protective surface layers formed on lithium in propylene carbonate solutions of LiClO/sub 4/ and LiAsF/sub 6/ at open circuit has been investigated by electrochemical pulse measurements. The results are consistent with the fast formation of a compact thin layer resulting from the reaction with residual water. This layer acts as a solid ionic conductor. Slow corrosion or decomposition processes produce a thicker porous overlayer.

Geronov, Y.; Schwager, F.; Muller, R.H.

1981-11-01

371

Interfacial reactions between graphite electrodes and propylene carbonate-based solutions: Electrolyte-concentration dependence of electrochemical lithium intercalation reaction  

Microsoft Academic Search

This study examines the electrochemical reactions occurring at graphite negative electrodes of lithium-ion batteries in a propylene carbonate (PC) electrolyte that contains different concentrations of lithium salts such as, LiClO4, LiPF6 or LiN(SO2C2F5)2. The electrode reactions are significantly affected by the electrolyte concentration. In concentrated solutions, lithium ions are reversibly intercalated within the graphite to form stage 1 lithium–graphite intercalation

Soon-Ki Jeong; Minoru Inaba; Yasutoshi Iriyama; Takeshi Abe; Zempachi Ogumi

2008-01-01

372

Rayleigh and raman scattering study of orientational and vibrational relaxation of carbon disulfide and chlorobenzene in solution  

NASA Astrophysics Data System (ADS)

We have studied the line shape of the 655 cm-1 Raman line in carbon disulfide and the 1002 cm-1 line of chlorobenzene, from which we determine the orientational and vibrational relaxation times. We present results obtained on the vibrational relaxation of chlorobenzene in solution with heptane, dimethyl sulfoxide, acetone, and quinoline. Peculiarities in the behavior of the polarized line width in various solvents is related to molecular processes which depend on the dipole moment and density of the solvent.

Atakhodzhaev, A. K.; Tukhvatullin, F. Kh.; Kleiner, I. P.; Zhumaboev, A.; Tursunkulov, A. A.

1995-02-01

373

Some organic and inorganic compounds as inhibitors for carbon steel corrosion in 3.5 percent NaCl solution  

Microsoft Academic Search

Purpose – To study the effects of the sodium salts of molybdate, tungstate and monovanadate as well as some derivatives of Neville-Winter acid azo dyes on the corrosion of carbon steel in 3.5 percent NaCl solution. Design\\/methodology\\/approach – Open circuit potential measurement and potentiostatic polarization techniques have been used. Findings – It was found that all the compounds had inhibition

M. Abdallah; A. Y. El-Etre; M. G. Soliman; E. M. Mabrouk

2006-01-01

374

Electrochemical study of carbon steel corrosion in buffered acetic acid solutions with chlorides and H 2S  

Microsoft Academic Search

In this work, the corrosion behavior of SAE 1018 carbon steel in buffered acetic acid (HAc) solutions containing chlorides, with and without H2S, was studied. Polarization curves obtained by different electrochemical techniques, indicate negligible modification of anodic slopes when adding H2S; however, the cathodic branch is more sensitive showing an accelerated reduction reaction in the presence of H2S. Interface characterization

M. A. Veloz; I. González

2002-01-01

375

Carbonate Coprecipitation of Gd 2O 3-doped CeO 2 solid solution nano-particles  

Microsoft Academic Search

This paper reports on the synthesis of 20mol% Gd2O3-doped CeO2 solid solution (20 GDC) nano-particles via carbonate co-precipitation. Precursors and calcined particles were characterized using TGA, XRD, BET, FESEM, and TEM. From the diffraction pattern using XRD with TEM, it was shown that the Gd3+ replaced the Ce4+ lattice in the fluorite structure (FCC) of CeO2, as opposed to it

A. I. Y. Tok; L. H. Luo; F. Y. C. Boey

2004-01-01

376

The use of rare earth cations as corrosion inhibitors for carbon steel in aerated NaCl solution  

Microsoft Academic Search

Purpose – Application of rare earth (RE) salts as a corrosion inhibitor was first proposed by Goldie and McCarrol in 1984. They showed that, with the addition of 0.001 M of Ce(NO3) or La(NO3) to 3.5% NaCl solution, the inhibition efficiencies were 91 and 82% for carbon steel, respectively. The aim of this paper is to study the inhibition of

A. Amadeh; S. R. Allahkaram; S. R. Hosseini; H. Moradi; A. Abdolhosseini

2008-01-01

377

Calcium-magnesium carbonate solid solutions from Holocene conglomerate cements and travertines in the Coast Range of California  

Microsoft Academic Search

Two calcium-magnesium carbonate solid solutions form Holocene travertines and conglomerate cements in fresh water stream channels of the Coast Range of California. Calcite does not yield the {015} diffraction maximum. The {006} diffraction maximum is lacking over most of the range of composition of calcite. Calcite has compositions from CaCO 3 to Ca 0.5 Mg 0.5 CO 3 . Dolomite

Ivan Barnes; James R. O'Neil

1971-01-01

378

Investigation on the corrosion process of carbon steel coated by HVOF WC\\/Co cermets in neutral solution  

Microsoft Academic Search

The corrosion protection afforded to a carbon steel substrate by two cermet coatings (WC\\/12 wt.% Co and WC\\/17 wt.% Co; 0.05, 0.01 and 0.2 mm coating thickness), applied by high velocity oxygen fuel (HVOF) technique, has been studied in 3.5% NaCl solutions. Potentiodynamic polarization curves of cermet constituents, substrate and coated samples, iron and cobalt dissolution kinetics under potentiostatic conditions

C Monticelli; A Frignani; F Zucchi

2004-01-01

379

Current distribution during galvanic corrosion of carbon steel welded with type-309 stainless steel in NaCl solution  

Microsoft Academic Search

Galvanic corrosion of carbon steel welded with type-309 stainless steel in NaCl solution was tentatively evaluated with a newly developed multi-channel electrode technique in which the welded specimen was divided into nine working electrodes (WEs), reconstructed in resin, and connected individually to an imaginary ground level of an electric circuit via relay switches. This allows the WEs to join a

Koji Fushimi; Atsushi Naganuma; Kazuhisa Azumi; Yuuzo Kawahara

2008-01-01

380

Coagulation of chitin and cellulose from 1-ethyl-3-methylimidazolium acetate ionic-liquid solutions using carbon dioxide.  

PubMed

Chemisorption of carbon dioxide by 1-ethyl-3-methylimidazolium acetate ([C2 mim][OAc]) provides a route to coagulate chitin and cellulose from [C2 mim][OAc] solutions without the use of high-boiling antisolvents (e.g., water or ethanol). The use of CO2 chemisorption as an alternative coagulating process has the potential to provide an economical and energy-efficient method for recycling the ionic liquid. PMID:24115399

Barber, Patrick S; Griggs, Chris S; Gurau, Gabriela; Liu, Zhen; Li, Shan; Li, Zengxi; Lu, Xingmei; Zhang, Suojiang; Rogers, Robin D

2013-11-18

381

Open circuit potential shifts of activated carbon in aqueous solutions during chemical and adsorption interactions  

Microsoft Academic Search

Interaction of certain inorganic and organic compounds with activated carbon and the effect of such interaction on open circuit\\u000a potential of activated carbon were studied. Open circuit potential shifts were observed for an overwhelming majority of the\\u000a substances and brands of activated carbons investigated. Both negative and positive potential shifts were observed. It was\\u000a shown that open circuit potential shifts

Mikhail M. Goldin; Vladimir A. Kolesnikov; Mogely Sh. Khubutiya; Alexander G. Volkov; Gary J. Blanchard; Anatoly K. Evseev; Mark M. Goldin

2008-01-01

382

Utilization of activated carbon produced from fruit juice industry solid waste for the adsorption of Yellow 18 from aqueous solutions.  

PubMed

The use of activated carbon obtained from sour cherry (Prunus cerasus L.) stones for the removal of a basic textile dye, which is Yellow 18, from aqueous solutions at different contact times, pH values and solution temperatures was investigated. The surface area and micropore volume of chemically modified activated carbon were 1704m(2)g(-1) and 0.984cm(3)g(-1), respectively. The experimental data indicated that the adsorption isotherms were well described by the Langmuir equilibrium isotherm equation and the calculated adsorption capacity was 75.76mgg(-1) at 318K. The adsorption kinetic of Yellow 18 obeys the pseudo-second-order kinetic model. The thermodynamic parameters were calculated to estimate the nature of adsorption. The activation energy of the system was calculated as 0.71-2.36kJ/mol. According to these results, prepared activated carbon could be used as a low-cost adsorbent to compare with the commercial activated carbon for the removal of Yellow 18 from wastewater. PMID:24656549

Angin, Dilek

2014-09-01

383

Interaction of organic acids with carbonate mineral surfaces in seawater and related solutions: I. Fatty acid adsorption  

NASA Astrophysics Data System (ADS)

The adsorption of C 4 to C 18 fatty acid anion homologs from seawater and related solutions was examined on calcite, aragonite, dolomite and magnesite surfaces. Butyrate, octanoate and laurate did not adsorb, while myristate, palmitate and stearate adsorbed on all carbonate surfaces. An increasing affinity for carbonate surfaces was found with increasing alkyl chain length for these fatty acids. Adsorption at low concentrations typical of marine waters is controlled by surface adsorption sites. At high concentration adsorption is governed by solution composition and limited by aqueous solubility. Adsorption-desorption reactions were characterized by a large resistant component that resulted in nonsingular isotherms. Myristate adsorption was enhanced in the presence of stearate cosorption. Orthophosphate in trace quantities was capable of displacing fatty acids from carbonate surfaces, but contrary to earlier studies, we found no major influence from magnesium ion on adsorption. The results of this study are interpreted in terms of a model based on the different types of forces which contribute to adsorption of these organic compounds. This model emphasizes the importance of organic aqueous solubility and the acid function as criteria controlling the adsorption of natural hydrophobic organics with carbonate mineral surfaces in aqueous fluids.

Zullig, James J.; Morse, John W.

1988-06-01

384

Preparation of activated carbons from Iris tectorum employing ferric nitrate as dopant for removal of tetracycline from aqueous solutions.  

PubMed

Ferric nitrate was employed to modify activated carbon prepared from Iris tectorum during H?PO? activation and ability of prepared activated carbon for removal of tetracycline (TC) was investigated. The properties of the activated carbon samples with or without ferric nitrate, ITAC-Fe and ITAC, were measured by scanning electron microscopy (SEM), N? adsorption/desorption isotherms, Fourier transform infrared spectroscopy (FTIR) and Boehm's titration. The results showed that mixing with iron increased the BET surface area, total pore volume and the adsorption capacity as compared to the original carbon. FTIR and Boehm's titration suggested that ITAC-Fe was characteristic of more acidic functional groups than ITAC. Adsorption of TC on both samples exhibited a strong pH-dependent behavior and adsorption capacity reduced rapidly with the increasing solution pH. The adsorption kinetics agreed well with the pseudo-second-order model and the adsorption isotherms data were well described by Langmuir model with the maximum adsorption capacity of 625.022 mg/g for ITAC and 769.231 mg/g for ITAC-Fe. The present work suggested that ITAC-Fe could be used to remove tetracycline effectively from aqueous solutions. PMID:24021870

Li, Gang; Zhang, Dongsheng; Wang, Man; Huang, Ji; Huang, Lihui

2013-12-01

385

Failure of hand disinfection with frequent hand washing: a need for prolonged field studies  

PubMed Central

In a prolonged field trial a 4% chlorhexidine digluconate detergent scrub (HibiscrubR), that had earlier proved to be an effective hand disinfectant, was studied in hospital wards. Finger tips were found to harbour more bacteria than the hand dorsum and the samples collected from them yielded more information on the bacteriological and dermatological effects of hand disinfectants in practice. In wards with a relatively low hand-washing frequency (less than 20 times in 8 hours) the bacteriological results resembled those obtained by in-use tests with volunteers. In the neonatal unit where the hand washing frequency was remarkably high, even occasionally over 100 times/8 h shift, an increase in the bacterial colony counts of the majority of the staff was recorded both before and after hand washing already after using the preparation for 1 week. Age, occupation and hand-washing frequency all correlated with the bacteriological results. Twenty-seven out of 37 persons complained of side effects such as wounds of finger tips and redness or heavy drying of the skin. Wounds, particularly on finger tips, resulted in the failure of disinfection. An increase in bacterial counts was sometimes noted without any dermatological or subjective changes. Drying of the skin was complained of less often when no increase in skin bacteria occurred. After the changeover of washing practice to a detergent followed by a rinse with spirit solution containing chlorhexidine and glycerol a decrease was recorded in the bacterial counts. It is concluded that more attention should be paid to long-term testing of hand washing and disinfection methods to ensure optimum final results in practice. It is obvious that the knowledge obtained from short time in-use testing cannot be applied to all conditions of use.

Ojajarvi, Juhani; Makela, Paavo; Rantasalo, Ilari

1977-01-01

386

Microbial contamination of a hexetidine mouth wash.  

PubMed

Twenty different bottles of a mouth wash containing 0.05% hexetidine as an active ingredient were examined for their microbiral contents. The results showed that all the tested bottles were contaminated with bacteria. Nine out of the twenty bottles contained more than 10(4) CFU/ml. Staphylococcus aureus was detected in one bottle, while Pseudomonas species were found in four bottles. Fungi were detected in 10 bottles, a fungal count of more than 100 fungus/ml were found in 12 out of the 19. Yeasts were detected in 16 bottles, Candida species were the most predominant with a rate of 11 out of the 16, while Saccharomyces species were found in 5 out of the 16. C. albicans, a definite oral pathogen, was found in 3 bottles. PMID:3116786

Abdelaziz, A A; Ashour, M S

1987-06-01

387

Carbon coal  

Microsoft Academic Search

The Carbon Coal Co. mines one million tons of coal per year from thin seams. In this arid area water requirements for coal washing are met by using treated waste water from Gallup's municipal waste treatment plant for which they pay 5 cents per 1000 gallons.

1981-01-01

388

Investigation of oxygen reduction on activated carbon electrodes in alkaline solution  

Microsoft Academic Search

Oxygen reduction has been studied on gas diffusion electrodes made from various kinds of activated carbon materials. The potentiodynamic method was used to study the electrochemical behavior of the reduction reaction, while nitrogen gas adsorption and powder X-ray diffraction were used to determine the pore size distribution and the crystal structure of the carbon material, respectively. The relationship between the

Deyang Qu

2007-01-01

389

Adsorption of Free and Complexed Metals from Solution by Activated Carbon.  

National Technical Information Service (NTIS)

Because of the interest in removing trace elements from water, the effect of two complexing agents of different solubilities on the adsorption of cadmium(II), zinc(II) and lead(II) by activated carbon was investigated. Studies were run to compare carbons ...

A. J. Rubin D. L. Mercer

1979-01-01

390

Development of a mobile heliostat mirror washing system  

SciTech Connect

This report describes the development, design and fabrication of an experimental system for washing heliostats. The economics of heliostat cleaning, the design requirements and the design and testing of the wash system are discussed. The heliostat wash system was designed to wash the heliostats located at the 10 MWe Central Receiver Pilot Plant located near Barstow, California. The plant, called Solar One, is a cooperative activity between the Department of Energy and the Associates: Southern California Edison, the Los Angeles Department of Water and Power, and the California Energy Commission. 12 figs., 4 tabs.

Not Available

1988-02-01

391

Multi-walled carbon nanotubes and poly(lactic acid) nanocomposite fibrous membranes prepared by solution blow spinning.  

PubMed

Nanocomposite fibers based on multi-walled carbon nanotubes (MWCNT) and poly(lactic acid) (PLA) were prepared by solution blow spinning (SBS). Fiber morphology was characterized by scanning electron microscopy (SEM) and optical microscopy (OM). Electrical, thermal, surface and crystalline properties of the spun fibers were evaluated, respectively, by conductivity measurements (4-point probe), thermogravimetric analyses (TGA), differential scanning calorimetry (DSC), contact angle and X-ray diffraction (XRD). OM analysis of the spun mats showed a poor dispersion of MWCNT in the matrix, however dispersion in solution was increased during spinning where droplets of PLA in solution loaded with MWCNT were pulled by the pressure drop at the nozzle, producing PLA fibers filled with MWCNT. Good electrical conductivity and hydrophobicity can be achieved at low carbon nanotube contents. When only 1 wt% MWCNT was added to low-crystalline PLA, surface conductivity of the composites increased from 5 x 10(-8) to 0.46 S/cm. Addition of MWCNT can slightly influence the degree of crystallinity of PLA fibers as studied by XRD and DSC. Thermogravimetric analyses showed that MWCNT loading can decrease the onset degradation temperature of the composites which was attributed to the catalytic effect of metallic residues in MWCNT. Moreover, it was demonstrated that hydrophilicity slightly increased with an increase in MWCNT content. These results show that solution blow spinning can also be used to produce nanocomposite fibers with many potential applications such as in sensors and biosensors. PMID:22755116

Oliveira, Juliano E; Zucolotto, Valtencir; Mattoso, Luiz H C; Medeiros, Eliton S

2012-03-01

392

Ion Enrichment on the Hydrophobic Carbon-based Surface in Aqueous Salt Solutions due to Cation-? Interactions  

NASA Astrophysics Data System (ADS)

By incorporating cation-? interactions to classic all-atoms force fields, we show that there is a clear enrichment of Na+ on a carbon-based ? electron-rich surface in NaCl solutions using molecular dynamics simulations. Interestingly, Cl- is also enriched to some extend on the surface due to the electrostatic interaction between Na+ and Cl-, although the hydrated Cl--? interaction is weak. The difference of the numbers of Na+ and Cl- accumulated at the interface leads to a significant negatively charged behavior in the solution, especially in nanoscale systems. Moreover, we find that the accumulation of the cations at the interfaces is universal since other cations (Li+, K+, Mg2+, Ca2+, Fe2+, Co2+, Cu2+, Cd2+, Cr2+, and Pb2+) have similar adsorption behaviors. For comparison, as in usual force field without the proper consideration of cation-? interactions, the ions near the surfaces have a similar density of ions in the solution.

Shi, Guosheng; Liu, Jian; Wang, Chunlei; Song, Bo; Tu, Yusong; Hu, Jun; Fang, Haiping

2013-12-01

393

Ion Enrichment on the Hydrophobic Carbon-based Surface in Aqueous Salt Solutions due to Cation-? Interactions  

PubMed Central

By incorporating cation-? interactions to classic all-atoms force fields, we show that there is a clear enrichment of Na+ on a carbon-based ? electron-rich surface in NaCl solutions using molecular dynamics simulations. Interestingly, Cl? is also enriched to some extend on the surface due to the electrostatic interaction between Na+ and Cl?, although the hydrated Cl?-? interaction is weak. The difference of the numbers of Na+ and Cl? accumulated at the interface leads to a significant negatively charged behavior in the solution, especially in nanoscale systems. Moreover, we find that the accumulation of the cations at the interfaces is universal since other cations (Li+, K+, Mg2+, Ca2+, Fe2+, Co2+, Cu2+, Cd2+, Cr2+, and Pb2+) have similar adsorption behaviors. For comparison, as in usual force field without the proper consideration of cation-? interactions, the ions near the surfaces have a similar density of ions in the solution.

Shi, Guosheng; Liu, Jian; Wang, Chunlei; Song, Bo; Tu, Yusong; Hu, Jun; Fang, Haiping

2013-01-01

394

Electrochemical splitting of calcium carbonate to increase solution alkalinity: implications for mitigation of carbon dioxide and ocean acidity.  

PubMed

Electrochemical splitting of calcium carbonate (e.g., as contained in limestone or other minerals) is explored as a means of forming dissolve hydroxides for absorbing, neutralizing, and storing carbon dioxide, and for restoring, preserving, or enhancing ocean calcification. While essentially insoluble in water, CaCO3 can be dissolved in the presence of the highly acidic anolyte of a water electrolysis cell. The resulting charged constituents, Ca2+ and C03(2-), migrate to the cathode and anode, respectively, forming Ca(OH)2 on the one hand and H2CO3 (or H2O and CO2) on the other. By maintaining a pH between 6 and 9, subsequent hydroxide reactions with CO2 primarily produce dissolved calcium bicarbonate, Ca(HCO3)2aq. Thus, for each mole of CaCO3 split there can be a net capture of up to 1 mol of CO2. Ca(HCO3)2aq is thus the carbon sequestrant that can be diluted and stored in the ocean, in natural or artificial surface water reservoirs, or underground. The theoretical work requirement for the reaction is 266 kJe per net mole CO2 consumed. Even with inefficiencies, a realized net energy expenditure lower than the preceding quantity appears possible considering energy recovery via oxidation of the H2 produced. The net process cost is estimated to be <$100/tonne CO2 mitigated. An experimental demonstration of the concept is presented, and further implementation issues are discussed. PMID:19192821

Rau, Greg H

2008-12-01

395

Equilibrium adsorption studies of some aromatic pollutants from dilute aqueous solutions on activated carbon at different temperatures  

SciTech Connect

Aqueous solutions of phenol, p-chlorophenol, and p-nitrophenol have been used to determine the adsorption isotherm for single solute systems on activated carbon at different temperatures. The experimental program has been conducted to investigate the influence of concentration and temperature. All the reported equilibrium isotherm equations have been tried on present and published experimental data. A generalized isotherm equation which was proposed by Khan et al. and tested for bi-solute adsorption data has been modified for single-solute system. The temperature dependency has also been incorporated into a generalized equation. It has been noticed that the Radke and Prausnitz and generalized isotherm equations could represent the entire data with a minimum average percentage error. The influence of different adsorbents, sorbate concentrations, and pH of aqueous solutions has also been discussed in detail. The temperature dependency has been investigated using both the Dubinin-Astakov and the modified generalized equation. The generalized equation describes the experimental and published data adequately and provides a single value of differential molar heat of adsorption, {Delta}H{sub ads}, for a single solute adsorption system. The Dubinin-Astakov isotherm equation has shown an increasing trend of {Delta}H{sub ads} as the loading of adsorbent has increased.

Khan, A.R.; Ataullah, R.; Al-Haddad, A. [Kuwait Univ., Safat (Kuwait). Dept. of Chemical Engineering] [Kuwait Univ., Safat (Kuwait). Dept. of Chemical Engineering

1997-10-01

396

Solution of shallow-water carbonates: An insignificant buffer against rising atmospheric CO2  

NASA Astrophysics Data System (ADS)

Model predictions suggest that the saturation state of surface ocean waters with respect to carbonate minerals will decline during the twenty-first century owing to increased invasion of atmospheric CO2. As a result, calcareous organisms may have difficulty calcifying, leading to production of weaker skeletons and greater vulnerability to erosion. Alternatively, it has been suggested that there will be no significant impact on coral reef ecosystems because any changes in saturation state and pH will be restored by dissolution of metastable carbonate minerals. To resolve this controversy, we employ a physical-biogeochemical box model representative of the shallow-water ocean environment. Numerical simulations demonstrate that the carbonate saturation state of surface waters could significantly decrease and hamper the biogenic production of CaCO3 during the twenty-first century. Similarly, the average saturation state of marine pore waters could decline significantly, inducing dissolution of metastable carbonate phases within the pore-water sediment system. Such dissolution could buffer the carbon chemistry of the pore waters, but overlying surface waters of reefs and other shallow-water carbonate environments will not accumulate sufficient alkalinity to buffer pH or carbonate saturation state changes owing to invasion of atmospheric CO2.

Andersson, Andreas J.; MacKenzie, Fred T.; Ver, Leah May

2003-06-01

397

An alternative paper based tissue washing method for mass spectrometry imaging: localized washing and fragile tissue analysis.  

PubMed

Surface treatment of biological tissue sections improves detection of peptides and proteins for mass spectrometry imaging. However, liquid surface treatments can result in diffusion of surface analytes and fragile tissue sections can be easily damaged by typical washing solvents. Here, we present a new surface washing procedure for mass spectrometry imaging. This procedure uses solvent wetted fiber-free paper to enable local washing of tissue sections for mass spectrometry imaging and tissue profiling experiments. In addition, the method allows fragile tissues that cannot be treated by conventional washing techniques to be analyzed by mass spectrometry imaging. PMID:21952901

van Hove, Erika R Amstalden; Smith, Donald F; Fornai, Lara; Glunde, Kristine; Heeren, Ron M A

2011-10-01

398

Capacitive Deionization of NH4ClO4 Solutions with Carbon Aerogel Electrodes.  

National Technical Information Service (NTIS)

A process for the capacitive deionization of water with a stack of carbon aerogel electrodes has been developed by Lawrence Livermore National Laboratory. Unlike ion exchange, one of the more conventional deionization processes, no chemicals are required ...

K. T. McSweeney D. Morris B. Rettle S. E. Kelley

1996-01-01

399

TRICHLOROETHYLENE ADSORPTION BY ACTIVATED CARBON PRELOADED WITH HUMIC SUBSTANCES: EFFECTS OF SOLUTION CHEMISTRY. (R828157)  

EPA Science Inventory

Abstract Trichloroethylene (TCE) adsorption by activated carbon previously loaded ("preloaded") with humic substances was found to decrease with increasing concentrations of monovalent ions (NaCl), calcium (until solubility was exceeded), or dissolved oxygen in...

400

Presence of Nanoparticles in Wash Water from Conventional Silver and Nano-silver Textiles.  

PubMed

Questions about how to regulate nanoenhanced products regularly arise as researchers determine possible nanoparticle transformation(s). Focusing concern on the incorporation and subsequent release of nano-Ag in fabrics often overshadows the fact that many "conventional silver" antimicrobials such as ionic silver, AgCl, metallic Ag, and other forms will also form different species of silver. In this study we used a laboratory washing machine to simulate the household laundering of a number of textiles prepared with known conventional Ag or nano-Ag treatments and a commercially available fabric incorporating yarns coated with bulk metallic Ag. Serial filtration allowed for quantification of total Ag released in various size fractions (>0.45 ?m, < 0.45 ?m, <0.1 ?m, and <10 kDa), while characterization of particles with TEM/EDX provided insight on Ag transformation mechanisms. Most conventional Ag additives yielded more total Ag and more nanoparticulate-sized Ag in the washing liquid than fabrics that used nano-Ag treatments. Incorporating nano-silver into the fiber (as opposed to surface treatments) yielded less total Ag during fabric washing. A variety of metallic Ag, AgCl, and Ag/S particles were observed in washing solution by TEM/EDX to various extents depending on the initial Ag speciation in the fabrics. Very similar particles were also observed when dissolved ionic Ag was added directly into the washing liquid. On the basis of the present study, we can state that all silver-treated textiles, regardless of whether the treatment is "conventional" or "nano", can be a source of silver nanoparticles in washing solution when laundering fabrics. Indeed, in this study we observed that textiles treated with "conventional" silver have equal or greater propensity to form nano-silver particles during washing conditions than those treated with "nano"-silver. This fact needs to be strongly considered when addressing the risks of nano-silver and emphasizes that regulatory assessment of nano-silver warrants a similar approach to conventional silver. PMID:24941455

Mitrano, Denise M; Rimmele, Elisa; Wichser, Adrian; Erni, Rolf; Height, Murray; Nowack, Bernd

2014-07-22

401

Interaction of aqueous solutions of phenol with commercial activated carbons: an adsorption and kinetic study  

Microsoft Academic Search

Three microporous commercial carbons were treated with HCl, H2F2 and HNO3. The effects of these treatments on the specific surface area and porosity, on the surface functional groups and on the adsorption behavior of phenol are studied by means of N2 adsorption at 77 K, temperature-programmed desorption (TPD) and phenol adsorption isotherms, respectively. The results show that there are carbonates

D. M. Nevskaia; A. Santianes; V. Muñoz; A. Guerrero-Ru??z

1999-01-01

402

Efficacy of household washing treatments for the control of Listeria monocytogenes on salad vegetables.  

PubMed

The efficacy of household decontamination methods at reducing Listeria monocytogenes on fresh lettuce (Lactuca sativa), cucumber (Cucumis sativus) and parsley (Petroselinum sativum) was studied. Inoculated vegetable pieces were immersed in washing solutions and surviving L. monocytogenes enumerated. Parameters investigated were storage temperature prior to washing, dipping water temperature, agitation, acetic acid concentration and immersion time. The results indicated that the storage temperature significantly affects the efficacy of dipping vegetables in water for the control of L. monocytogenes, as the reduction in count was greatest when products had been stored at cooler temperatures. Decontamination with acetic acid (up to 2.0% v/v) was shown to have some effect in most cases, but the highest observed decrease in count was 2.6 log cfu/g. Experiments investigating the effect of exposure time to acetic acid (0.5% and 1.0% v/v, up to 30 min immersion) indicated that immersing the vegetables for more than 10 min is of minimal benefit. The most significant factor affecting washing and decontamination efficacy was the vegetable itself: L. monocytogenes colonizing cucumber epidermis was far more resistant to removal by washing and to acid treatment than that on the leafy vegetables, and L. monocytogenes on parsley was the most susceptible. This shows that published decontamination experiments (often performed with lettuce) cannot necessarily be extrapolated to other vegetables. PMID:23107504

Nastou, Aikaterini; Rhoades, Jonathan; Smirniotis, Petros; Makri, Ioanna; Kontominas, Michael; Likotrafiti, Eleni

2012-10-15

403

Effect of ammonium-salt solutions on the surface properties of carbon fibers in electrochemical anodic oxidation  

NASA Astrophysics Data System (ADS)

The surfaces of polyacrylonitrile-based carbon fibers were treated by an electrochemical anodic method. Three different kinds of ammonium-salt solutions namely NH4HCO3, (NH4)2CO3 and (NH4)3PO4 were respectively chosen as the electrolytes. The effect of these electrolytes on the surface structure was studied by scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The results showed that longitudinal grooves on the fiber surface became more well-defined and much deeper after surface treatment, and the root mean square roughness (RMS) of carbon fiber surface increased from 4.6 nm for untreated fibers to 13.5 nm for treated fibers in (NH4)3PO4 electrolytes. The concentration of oxygen and nitrogen atomic on the fiber surface increased after surface treatment. The tensile strength of oxidized fibers had an obvious decrease, whereas the interlaminar shear strength (ILSS) value of corresponding carbon fiber reinforced polymers (CFRPs) increased in a large extent. The intensity of oxidative reaction varied with the change of ammonium-salt solutions and electrochemical oxidation in (NH4)3PO4 electrolyte was of the most violence. The corresponding mechanism was also discussed and the result showed that the higher the concentration of OH- ions in the electrolytes, the violent the oxidative reaction happened.

Qian, Xin; Wang, Xuefei; Ouyang, Qin; Chen, Yousi; Yan, Qing

2012-10-01

404

Activated carbons from coal/pitch and polyethylene terephthalate blends for the removal of phenols from aqueous solutions  

SciTech Connect

Blends of two bituminous coals and a coal-tar pitch (CTP) with polyethylene terephthalate (PET) were evaluated as precursors of activated carbons (ACs). The intensity of the interactions between the raw materials, coal/CTP and PET during copyrolysis was closely observed by means of thermogravimetric analysis. In addition, the homogeneity of the carbon matrix of the chars produced at 800{sup o}C in a horizontal oven was studied by polarized light optical microscopy. Activated carbons were prepared from single components and their blends (1:1 w/w) by subjecting them to carbonization up to 800{sup o}C in a horizontal oven and then activation with steam at 800{sup o}C to 50% burnoff. The porous structure of the ACs was determined by sorption of N{sub 2} at 77 K and of CO{sub 2} at 273 K. The PET-containing blends produced microporous activated carbons with a maximum BET surface area of nearly 1100 m{sup 2} g{sup -1} and a maximum micropore size distribution of 0.6-0.8 nm in the case of the AC from the CTP/PET blend. The addition of PET to a bituminous coal was compared with the preoxidation of coal P in air as a way to reduce thermoplasticity and to promote the development of the porous structure. The modification of bituminous coals by PET appeared to be more effective than conventional coal preoxidation treatment. The resultant ACs were tested by measuring their effectiveness in removing phenols from an aqueous solution. The adsorption of p-chlorophenol (PCP) by the ACs prepared from the PET-containing blends was slightly higher than for the commercial activated carbon. The ability to adsorb PCP was found to be related to the volume of the super-micropores.

Ewa Lorenc-Grabowska; Grazyna Gryglewicz; Jacek Machnikowski [Wroclaw University of Technology, Gdaska (Poland). Department of Polymer and Carbonaceous Materials

2009-05-15

405

Crud in Solvent Washing Process for Nuclear Fuel Reprocessing  

Microsoft Academic Search

In a solvent washing process for nuclear fuel reprocessing, one of the important problems is a formation of stable emulsions between organic and aqueous phases. These emulsions are called interfacial “crud”. Crud is defined as an emulsion stabilized by finely dispersed solids. These stable emulsions lead to decreased washing efficiency, lower phase separation, disturbance of the interfacial control at the

Hiroshi SUGAI

1992-01-01

406

EPA SITE DEMONSTRATION OF THE BIOTROL SOIL WASHING PROCESS  

EPA Science Inventory

A pilot-scale soil washing process, patented by BioTrol, Inc., was demonstrate on soil contaminated by wood treating waste, primarily pentachlorophenol (PCP) and creosote-derived polynuclear aromatic hydrocarbons (PAHs). Although soil washing was the main object of this demonstra...

407

Compliance of hand washing practices: Theory versus practice  

Microsoft Academic Search

Hand washing remains an important preventative method for making the transmission of nosocomial infections redundant. Despite awareness by health workers of the practices required and of the legislation governing hand washing, the study reported here found that compliance to these procedures was quite poor. The results of two surveys distributed to health workers and direct observation by clinical staff in

Lorette Roberts; Patrick Bolton; Sonia Asman

1998-01-01

408

Wash room, bunkhouse, first floor interior. This room is a ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Wash room, bunkhouse, first floor interior. This room is a screened porch with the original sinks extant. Light and ventilation was borrowed from the wash room into the toilets and bathing rooms. - Sespe Ranch, Bunkhouse, 2896 Telegraph Road, Fillmore, Ventura County, CA

409

33 CFR 207.750 - Puget Sound Area, Wash.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Puget Sound Area, Wash. 207.750 Section 207...NAVIGATION REGULATIONS § 207.750 Puget Sound Area, Wash. (a) Waterway connecting...vessels approaching the locks from Puget Sound shall be alert to receive and shall...

2013-07-01

410

33 CFR 162.235 - Puget Sound Area, Wash.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Puget Sound Area, Wash. 162.235 Section 162...NAVIGATION REGULATIONS § 162.235 Puget Sound Area, Wash. (a) Waterway connecting...one short whistle. Southbound boats shall sound the signal within 600 yards of Port...

2013-07-01

411

Temperature effects on the performance of PMAN-derived carbon anodes in 1M LiPF{sub 6}/EC-DMC solution  

SciTech Connect

The effect of temperature on the reversible and irreversible capacities of disordered carbons derived from polymethacryonitrile (PMAN) and divinylbenzene (DVB) copolymers was studied in 1 M LiPF{sub 6}/ethylene carbonate (EC)-dimethyl carbonate (DMC) (1:1 v/v) solution by galvanostatic cycling. The kinetics of passive film formation were examined by complex-impedance spectroscopy. Temperatures of 5, 21, and 35 C were used in the study.

Guidotti, R.A.; Johnson, B.J.

1998-04-01

412

Surface film formation on a graphite negative electrode in lithium-ion batteries: AFM study on the effects of co-solvents in ethylene carbonate-based solutions  

Microsoft Academic Search

In situ AFM observation of the basal plane of highly oriented pyrolytic graphite (HOPG) was performed before and after cyclic voltammetry in 1 mol dm?3 LiClO4 dissolved in ethylene carbonate (EC), EC+diethyl carbonate (DEC), and EC+dimethyl carbonate (DMC) to clarify the effects of co-solvents in EC-based solutions on surface film formation on graphite negative electrodes in lithium-ion cells. In each

Soon-Ki Jeong; Minoru Inaba; Yasutoshi Iriyama; Takeshi Abe; Zempachi Ogumi

2002-01-01

413

Utilization of various agricultural wastes for activated carbon preparation and application for the removal of dyes and metal ions from aqueous solutions  

Microsoft Academic Search

Activated carbons were prepared from the agricultural solid wastes, silk cotton hull, coconut tree sawdust, sago waste, maize cob and banana pith and used to eliminate heavy metals and dyes from aqueous solution. Adsorption of all dyes and metal ions required a very short time and gave quantitative removal. Experimental results show all carbons were effective for the removal of

K Kadirvelu; M Kavipriya; C Karthika; M Radhika; N Vennilamani; S Pattabhi

2003-01-01

414

Comparative Study of Zn, Cd, and Pb Removal From Water Solution Using Natural Clinoptilolitic Zeolite and Commercial Granulated Activated Carbon. Equilibrium of Adsorption  

Microsoft Academic Search

The aim of this work is to study the effectiveness of regional, low-cost natural clinoptilolitic zeolite tuff in heavy metal ions removal from aqueous solution, through comparative study with commercial granulated activated carbon. The equilibrium of adsorption of Cd, Pb, and Zn on both adsorbents have been determined at 25, 35, and 45°C in batch mode. The granulated activated carbon

M. Minceva; R. Fajgar; L. Markovska; V. Meshko

2008-01-01

415

Metabolism of Red Beet Slices I. Effects of Washing 1  

PubMed Central

The changes in relative participation of pathways of glucose catabolism in red beet slices during washing have been examined using specifically 14C labeled glucoses. Washing of these slices brings about an increase in participation of the pentose phosphate pathway. The composition of the washing medium influences slightly the extent of change in pathway participation. The activity level of certain enzymes participating in the initial stages of glucose catabolism has been measured in fresh and washed beet slices. Fresh slices which barely metabolized gluconate were found to have very little 6-phosphogluconate dehydrogenase activity. Washing brings about a dramatic increase in 6-phosphogluconate dehydrogenase activity and this increase was accompanied by a marked increase in the ability of the slices to metabolize gluconate. In red beet slices the TPNH generated via pentose phosphate pathway appears to be utilized for biosynthetic reductions rather than as respiratory substrate.

Reed, D. J.; Kolattukudy, P. E.

1966-01-01

416

Fractionation of dissolved organic carbon from soil solution with immobilized metal ion affinity chromatography  

Microsoft Academic Search

Summary The presence and identity of Cu-complexing ligands in soil solution strongly affects biogeochemistry, bioavailability and the fate of Cu in soils. In this study, we compared the influence of heavy metal pollution, vegetation and soil type on the amount and characterization of ligands able to form ternary complexes with Cu in soil solution. For separation and characterization, we applied

I. PAUNOVIC; R. S CHULINa; B. N OWACK

417

Origin of gasoline-range hydrocarbons and their migration by solution in carbon dioxide in Norton basin, Alaska.  

USGS Publications Warehouse

Carbon dioxide from a submarine seep in Norton Sound carries a minor component of gas- and gasoline-range hydrocarbons. The molecular and isotopic compositions of the hydrocarbon gases and the presence of gasoline-range hydrocarbons indicate that these molecules are derived from thermal alteration of marine and/or nonmarine organic matter buried within Norton basin. The gasoline-range hydrocarbon distribution suggests that the hydrocarbon mixture is an immature petroleum-like condensate of lower temperature origin than normal crude oil. The submarine seep provides a natural example in support of a carbon dioxide solution transport mechanism thought to be operative in the migration of hydrocarbons in certain reservoirs.-Authors

Kvenvolden, K. A.; Claypool, G. E.

1980-01-01

418

Study On Adsorption of Bromate From Aqueous Solution On Modified Activated Carbon  

NASA Astrophysics Data System (ADS)

A coal-based activated carbon was treated chemically with nitric acid, sodium hydroxide and ammonia for its surface modification, and its adsorption capacity was investigated with bromate. Several techniques were used to characterize the physicochemical properties of these materials including BET, XPS, pHpzc and Boehm titration. The results indicated that the specific surface area of the activated carbon decreased after oxidation with nitric acid. But the amount of surface acidic oxygen-containing functional groups of the oxidized sample increased compared to the raw carbon and the points of zero charge (pHpzc) decreased. The specific surface area of the activated carbon also decreased after sodium hydroxide treatment and the points of zero charge increased. The changes of surface chemical properties after the ammonia treatment was opposite to the oxidized sample. As a result, the pHpzc of the carbon was increased to near pH9.3, the amount of surface basic groups was increased. Furthermore, the data of bromate adsorption on all the samples were fitted to the Langmuir isotherm model well which indicates monolayer adsorption. In addition, the adsorption capacity of ammonia treatment sample was the highest and its saturated adsorption capacity reached 1.55 mg/g. A strong correlation was found between basic groups and adsorption capacity of bromate. Enhancement of basic groups was favorable for bromate removal.

Liu, Tong-Mian; Cui, Fu-Yi; Zhao, Zhi-Wei; Liu, Dong-Mei; Zhu, Qi; Wang, Huan

2010-11-01

419

Investigation of Emulsion Formation in Solvent Washing in the Caustic-Side Solvent Extraction (CSSX) Process  

SciTech Connect

The effects on phase separation and emulsion formation of variables present in the caustic washing of solvent in the caustic-side solvent extraction process have been investigated. The evaluation program was performed in two experiments; results of the first experiment were used to determine conditions for the second test. In the first experiment, the effects of solvent degradation product concentrations (4-sec-butylphenol and dioctylamine), wash solution NaOH concentration, and solvent-to-wash solution volume ratio (O:A) on phase separation were examined. Phase separation performance was quantified in terms of the dimensionless dispersion number, which is also a variable used in the prediction of centrifugal contactor performance by computational means. In the second experiment, phase separation performance in a 5-cm centrifugal contactor was investigated as a function of contactor speed, aqueous-phase NaOH concentration, and solvent-to-wash volume ratio. Separation performance was quantified in terms of the maximum throughput that could be achieved without resulting in >1% contamination of either effluent phase with the opposing phase. Results of the first experiment indicated that none of the variables considered affected phase separation performance at a 95% significance level and that dioctylamine concentration was the only single factor that affected phase separation at a 90% significance level. The results do indicate 90% significance for interaction effects between NaOH concentration and O:A and between NaOH concentration and 4-sec-butylphenol concentration. However, none of the dispersion numbers obtained were inconsistent with values obtained in previous studies of CSSX solvent formulations. Results of contactor performance tests indicated that acceptable phase separation was achieved at relatively high throughputs over a range of O:A ratios and wash solution NaOH concentrations. Emulsion formation during contactor operation was observed only under off-normal conditions. Taken together, the results of the work described in this report indicate that from the perspective of phase separation efficiency, CSSX solvent washing can be performed over a range of conditions. Consequently, contaminant removal considerations should not be affected by hydraulic performance concerns in the selection of parameters for solvent treatment.

Birdwell, JR.J.F.

2002-06-27

420

Agricultural based activated carbons for the removal of dyes from aqueous solutions: a review.  

PubMed

This review evaluates a number of different agricultural waste adsorbents and types of dyes. Certain wastewater containing different dye contaminants causes serious environmental problems. Recently, growing research interest in the production of carbon based has been focused on agricultural by-products. Low cost adsorbents derived from agricultural wastes have demonstrated outstanding capabilities for the removal of dyes from wastewater. Therefore, low cost agricultural waste adsorbents can be viable alternatives to activated carbon for the treatment of contaminated wastewater. The use of cheap and eco-friendly adsorbents have been studied as an alternative substitution of activated carbon for the removal dyes from wastewater. The dye adsorption capacities of agricultural waste adsorbents vary, depending on the characteristics of the individual adsorbent, the extent of surface modification and the initial concentration of adsorbate. PMID:19181447

Demirbas, Ayhan

2009-08-15

421

Old Groundwater, Interbasin Groundwater Flow, Magmatic Solutes, and Hydrologic Fluxes of Carbon in a Lowland Costa Rican Rainforest  

NASA Astrophysics Data System (ADS)

Carbon (C), helium (He), and chloride (Cl) concentrations and isotopes were measured in groundwater and surface-water in a lowland Costa Rican rainforest at the foot of Volcan Barva (a 2900 m peak that is one of the largest in the Cordillera Central of Costa Rica). Results are consistent with the presence and mixing of two distinct groundwaters: (1) high-solute bedrock groundwater representing interbasin groundwater flow (IGF) into the rainforest watersheds, and (2) low-solute local groundwater recharged within the lowland rainforest watersheds. In bedrock groundwater, high ^13C (-4.89 o/oo), low 14C (7.98 pmC), high R/RA for He (6.88), and low 36Cl/Cl (17x10-15) suggest that elevated DIC, He, and Cl concentrations are derived from magmatic outgassing and/or weathering of volcanic rock beneath nearby Volcan Barva. In local groundwater, the magmatic signature is absent and data suggest atmospheric sources for He and Cl and a biogenic soil-gas CO2 source for DIC. 14C dating suggests the age of bedrock groundwater is 2700-4300 years (most likely at the lower end of the range). Local groundwater has 14C>100 pmC, indicating the presence of "bomb carbon" and thus ages less than ~50 years for these samples collected in 2006. Overall, the C, He, and Cl data are consistent with a prior conceptual hydrologic model developed with major ion and water-balance data from this tropical rainforest: (1) the large variation in solute concentrations can be explained by mixing of the two distinct groundwaters, (2) bedrock groundwater is much older than local water, (3) elevated solute concentrations in bedrock groundwater are derived from volcanic fluids and/or rock, and (4) local water has not had significant interaction with volcanic rock. Tracers with different behaviors and capabilities converge on the same hydrologic interpretation. Also, transport of magmatic CO2 into the lowland rainforest (as DIC in the IGF) seems to be significant relative to other large ecosystem-level carbon fluxes. Dissolved carbon export from the watersheds via streamflow is dominated by DIC (DOC accounts for

Genereux, D. P.; Webb, M.; Solomon, D. K.

2009-04-01

422

Study of poly(3,4-ethylenedioxythiophene) films prepared in propylene carbonate solutions containing different lithium salts  

Microsoft Academic Search

Poly(3,4-ethylenedioxythiophene) [PEDOT] was obtained from organic electrolytes containing the monomer in a solution of propylene carbonate (PC). Different lithium salts (LiBF4, LiClO4, LiPF6 or LiN(SO2C2F5)2 [LiBETI]) were used as supporting electrolytes. The electrosynthesis was conducted under galvanostatic conditions on to a platinum–quartz microelectrode up to a charge density of 200 mCcm?2. Scanning electron microscopy (SEM) performed on the deposited polymers

F. Blanchard; B. Carré; F. Bonhomme; P. Biensan; H. Pagès; D. Lemordant

2004-01-01

423

Semiconducting single-walled carbon nanotubes exposed to distilled water and aqueous solution: Electrical measurement and theoretical calculation  

NASA Astrophysics Data System (ADS)

We fabricate and measure a single-walled carbon nanotube transistor having a liquid-gate electrode. The ratio value of Ion/Ioff is as high as 104, indicating the presence of a semiconducting channel. A passivation layer over the source/drain electrode greatly suppresses the liquid-gate leakage by about three orders of magnitude. The channel currents are noticeably distinct between two liquid samples: distilled water and aqueous solution (1×10-4 M NaCl). This biological sensing ability is attributed to the different electrical double-layer capacitances with respect to the bulk part of the channel. The corresponding theoretical calculation is carried out in detail.

Lu, Ming-Pei; Hsiao, Cheng-Yun; Lo, Po-Yuan; Wei, Jeng-Hua; Yang, Yuh-Shyong; Chen, Ming-Jer

2006-01-01

424

Improved mechanical properties of solution-cast silicone film reinforced with electrospun polyurethane nanofiber containing carbon nanotubes  

NASA Astrophysics Data System (ADS)

In this study, we describe the enhancing ability of electrospun polyurethane (PU) nanofibers containing carbon nanotubes (CNTs) as nanofillers for silicone film in improving the physico-mechanical properties of the composite material. We prepared the samples combining two simple techniques: solution casting and electrospinning. Neat PU nanofibers alone are good reinforcing materials but the presence of CNTs inside the PU nanofibers has drastically improved the mechanical properties of the silicone composite film. The silicone film increased its tensile strength by 226% and its tensile modulus by more than 14-fold when CNT/PU nanofibers were incorporated.

Tijing, Leonard D.; Park, Chan-Hee; Kang, Seung-Ji; Amarjargal, Altangerel; Kim, Tae-Hyung; Pant, Hem Raj; Kim, Han Joo; Lee, Dong Hwan; Kim, Cheol Sang

2013-01-01

425

Fundamental effects of aging on creep properties of solution-treated low-carbon n-155 alloy  

NASA Technical Reports Server (NTRS)

A method is developed whereby the fundamental mechanisms are investigated by which processing, heat treatment, and chemical composition control the properties of alloys at high temperatures. The method used metallographic examination -- both optical and electronic --studies of x-ray diffraction-line widths, intensities, and lattice parameters, and hardness surveys to evaluate fundamental structural conditions. Mechanical properties at high temperatures are then measured and correlated with these measured structural conditions. In accordance with this method, a study was made of the fundamental mechanism by which aging controlled the short-time creep and rupture properties of solution-treated low-carbon n-155 alloy at 1200 degrees F.

Frey, D N; Freeman, J W; White, A E

1950-01-01

426

Fabrication of the supersaturated solid solution of carbon in copper by mechanical alloying  

SciTech Connect

Mechanical alloying of powder mixtures of copper and graphite was performed in a high energy ball mill. The as-milled powder was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy, respectively. These investigations indicated that high energy ball milling could largely extend the solid solubility of carbon in copper and the 4 wt.% C was dissolved in Cu. It was ascribed to the decrease of the grain size and the increase of the lattice strain. Nanostructures, amorphous carbon and lamellar graphite were observed in the as-milled powder after milling for 24 h.

Liu Xueran [Key Laboratory of Automobile Materials of Ministry of Education and Department of Materials Science and Engineering, Jilin University, No. 5988 Renmin Street, Changchun 130025 (China); Liu Yongbing [Key Laboratory of Automobile Materials of Ministry of Education and Department of Materials Science and Engineering, Jilin University, No. 5988 Renmin Street, Changchun 130025 (China); Ran Xu [Key Laboratory of Automobile Materials of Ministry of Education and Department of Materials Science and Engineering, Jilin University, No. 5988 Renmin Street, Changchun 130025 (China); Department of Materials Science and Engineering, Changchun Institute of Technology, No. 17 Yan'an Street, Changchun 130012 (China); An Jian [Key Laboratory of Automobile Materials of Ministry of Education and Department of Materials Science and Engineering, Jilin University, No. 5988 Renmin Street, Changchun 130025 (China); Cao Zhanyi [Key Laboratory of Automobile Materials of Ministry of Education and Department of Materials Science and Engineering, Jilin University, No. 5988 Renmin Street, Changchun 130025 (China)]. E-mail: caozy@jlu.edu.cn

2007-06-15

427

Precipitation polymerization of hydrophobically modified polyelectrolyte poly(AA-co-ODA) in supercritical carbon dioxide and solution rheology properties  

NASA Astrophysics Data System (ADS)

Hydrophobically modified (HM) polyelectrolytes were prepared by using precipitation polymerization of acrylic acid (AA) and octadecyl acrylate (ODA) in various molar ratios in supercritical carbon dioxide. The product was obtained in the form of a white powder and the micrographs show aggregates of primary particles < 1 ?m in size. The effects of polymer concentration, ODA content in polymer, surfactant, shear time, shear rate on the apparent viscosity were investigated. The reason leaded to a significant viscosity enhancement was discussed. Steady-state and oscillatory tests of solution were also investigated. Solution exhibited shear thinning behavior and thixotropy. Polymers contain octadecyl acrylate (3.4 mol%) at 0.2 g/dL behaved as high entanglement structures or association gels, since the modulus G' were being higher than G? throughout the frequency range. The comparison of apparent and complex viscosities confirmed the association gel properties.

Zhang, Huaiping; Li, Wei; Cao, Qing; Chen, Mingcai

2014-05-01

428

PEROXIDE-INHIBITED DECONTAMINATION SOLUTIONS FOR CARBON STEEL AND OTHER METALS IN THE GAS-COOLED REACTOR PROGRAM. Progress Report, November 1959July 1962  

Microsoft Academic Search

A search for solutions suitable for dissolving uranium dioxide powder or ; lumps and yet noncorrosive enough to be used for decontaminating the carbon steel ; EGCR charge and service machines resulted in the development of buffered oxalate ; solutions of controlled temperature and pH, with hydrogen peroxide added to act ; as corrosion inhibitor, UOâ oxidizer, and decontamination aid.

Meservey

1963-01-01

429

Effect of Metal Impurities on Adsorption of Gold by Activated Carbon in Cyanide Solutions.  

National Technical Information Service (NTIS)

The U.S. Bureau of Mines performed batch equilibrium contact experiments to examine the ability of activated coconut-shell carbon to adsorb various metal cyanide complexes. Tests were also conducted to determine the effect the cyanide complex impurities m...

S. A. N. Sheya G. R. Palmer

1989-01-01

430

Characterizing the effect of carbon steel exposure in sulfide containing solutions to microbially induced corrosion  

Microsoft Academic Search

This article compares the electrochemical effects induced by inorganic sulfide and sulfate reducing bacteria on the corrosion of carbon steel – a subject of concern for pipelines. Biological microcosms, containing varying concentrations of bioorganic content, were studied to investigate changes to the morphology of biofilms and corrosion product deposits. Raman analysis indicated mackinawite (FeS1?x) was the dominant iron sulfide phase

B. W. A. Sherar; I. M. Power; P. G. Keech; S. Mitlin; G. Southam; D. W. Shoesmith

2011-01-01

431

Using semi-analytic solutions to approximate the area of potential impact for carbon dioxide injection  

EPA Science Inventory

This study examines using the threshold critical pressure increase and the extent of the carbon dioxide (CO2) plume to delineate the area of potential impact (AoPI) for geologic CO2 storage projects. The combined area covering both the CO2 plume and the region where the pressure ...

432

A surface complexation model of the carbonate mineral-aqueous solution interface  

Microsoft Academic Search

A surface complexation model for the chemical structure and reactivity of the carbonatewater interface is presented. The model postulates the formation of the hydration species >CO 3 H 0 and >MeOH 0 at the surface of a divalent metal carbonate MeCO 3 (Me = Ca, Mn, Fe, etc.). The existence of these primary hydration species is supported by spectroscopic data.

Philippe van Cappellen; Laurent Charlet; Werner Stumm; Paul Wersin

1993-01-01

433

The influence of sodium carbonate on sodium aluminosilicate crystallisation and solubility in sodium aluminate solutions  

Microsoft Academic Search

Isothermal batch precipitation experiments have been carried out in synthetic Bayer liquors to investigate the effects of sodium carbonate concentration on both silica solubility and the crystallisation of sodium aluminosilicates. At both 90 and 160°C cancrinite (generically defined as a sodium aluminosilicate of space group P63) is the stable solid phase. Sodalite (generically defined as a sodium aluminosilicate with space

Kali Zheng; Andrea R. Gerson; Jonas Addai-Mensah; Roger St. C. Smart

1997-01-01

434

Engineering Solutions to Optimise the Design of Carbon-Neutral Tall Office Buildings  

Microsoft Academic Search

Energy efficiency differs by building use and type as well as prevailing climatic conditions. This paper introduces a framework for assessing particular building design configurations against relevant performance criteria which can permit design improvement through the use of multi-objective optimisation. The resulting generalised model has the potential to give new insight to the engineering challenges facing the design of carbon-neutral

Mark Pitman; Andrew King

435

Transport of carbon, nitrogen, phosphorus, and major solutes in the Gambia River, West Africa  

Microsoft Academic Search

Transport of solutes and particulate materials and their variation with discharge were studied for 1 year (July 1980-June 1981) in the Gambia River in the tropical savanna of West Africa. The water is a dilute solution of SiOâ and HCOâ⁻. Na\\/sup +\\/, K\\/sup +\\/, Cl⁻, and total dissolved nitrogen showed no significant relation with discharge. Ca\\/sup 2 +\\/, Mg\\/sup 2

LANCE F. W. LESACK; ROBERT E. HECKY; JOHN M. MELACK

1984-01-01

436

Wheat Gluten Swelling and Partial Solubility with Potential Impact on Starch-from-Gluten Separation by Ethanol Washing  

Microsoft Academic Search

Cereal Chem. 76(6):843-845 Swelling of wheat gluten may be a contributing factor in washing or displacement separation of gluten and starch using cold ethanol. To test this hypothesis, dissolution and swe lling (settled volume or mass absorp- tion) of a commercial gluten are reported here for the first time as a function of both temperature and ethanol solution concentration. In

G. H. Robertson; T. K. Cao; I. Ong

1999-01-01

437

Experimental study of the constituents of space wash water  

NASA Technical Reports Server (NTRS)

This report presents experimental data, obtained under controlled conditions, which quantify the various constituents of human origin that may be expected in space wash water. The experiments were conducted with a simulated crew of two male and two female subjects. The data show that the expected wash water contaminants originating from human secretions are substantially lower than theoretical projections indicated. The data presented are immediately useful and may have considerable impact on the tradeoff comparisons among various unit processes and systems under consideration by NASA for recycling space wash water.

Putnam, D. F.; Colombo, G. V.

1975-01-01

438

Taguchi optimization approach for Pb(II) and Hg(II) removal from aqueous solutions using modified mesoporous carbon.  

PubMed

Using the Taguchi method, this study presents a systematic optimization approach for removal of lead (Pb) and mercury (Hg) by a nanostructure, zinc oxide-modified mesoporous carbon CMK-3 denoted as Zn-OCMK-3. CMK-3 was synthesized by using SBA-15 and then oxidized by nitric acid. The zinc oxide was loaded to the modified CMK-3 by the equilibrium adsorption of Zn(II) ions from aqueous solution followed by calcination to convert zinc nitrate to zinc oxide. The CMK-3 had porous structure and high specific surface area which can accommodate zinc oxide in a spreading manner, the zinc oxide connects to the carbon surface via oxygen atoms. The controllable factors such as agitation time, initial concentration, temperature, dose and pH of solution have been optimized. Under optimum conditions, the pollutant removal efficiency (PRE) was 97.25% for Pb(II) and 99% for Hg(II). The percentage contribution of each controllable factor was also determined. The initial concentration of pollutant is the most influential factor, and its value of percentage contribution is up to 31% and 43% for Pb and Hg, respectively. Our results show that the Zn-OCMK-3 is an effective nanoadsorbent for lead and mercury pollution remediation. Langmuir and Freundlich adsorption isotherms were used to model the equilibrium adsorption data for Pb(II) and Hg(II). PMID:21733626

Zolfaghari, Ghasem; Esmaili-Sari, Abbas; Anbia, Mansoor; Younesi, Habibollah; Amirmahmoodi, Shahram; Ghafari-Nazari, Ali

2011-09-15

439

Adsorption of anionic and cationic dyes on ferromagnetic ordered mesoporous carbon from aqueous solution: Equilibrium, thermodynamic and kinetics.  

PubMed

Ordered mesoporous carbon (Fe-CMK-3) with iron magnetic nanoparticles was prepared by a casting process via SBA-15 silica as template and anthracene as carbon source, was used as a magnetic adsorbent for the removal of anionic dye Orange II (O II) and cationic dye methylene blue (MB) from aqueous solution. TEM and magnetometer images showed that the iron magnetic nanoparticles were successfully embedded in the interior of the mesoporous carbon. The effect of various process parameters such as temperature (25-45°C), initial concentration (100-500mgL(-1)) and pH (2-12) were performed. Equilibrium adsorption isotherms and kinetics were also studied. The equilibrium experimental data were analyzed by the Langmuir, Freundlich, Temkin and Redlich-Peterson model. The equilibrium data for two dyes adsorption was fitted to the Langmuir, and the maximum monolayer adsorption capacity for O II and MB dyes were 269 and 316mgg(-1), respectively. Pseudo-first-order and pseudo-second-order kinetic and intraparticle diffusion model were used to evaluate the adsorption kinetic data. The kinetic data of two dyes could be better described by the pseudo second-order model. Thermodynamic data of the adsorption process were also obtained. It was found that the adsorption process of the two dyes were spontaneous and exothermic. PMID:24973701

Peng, Xiaoming; Huang, Dengpo; Odoom-Wubah, Tareque; Fu, Dafang; Huang, Jiale; Qin, Qingdong

2014-09-15

440

Corrosion inhibition of carbon steel in 0.5 M NaCl aqueous solution by humid air plasma treatment  

NASA Astrophysics Data System (ADS)

Carbon steel (C75) is exposed to highly reactive species such as hydroxyl radicals OH created by a gliding arc discharge (GAD) in humid air at atmospheric pressure. The protective properties of carbon steel treated by GAD are studied versus different treatment times (t) and for an immersion in corroding 0.5 M sodium chloride solution during 24 h. Evolutions of corrosion rate are studied using weight loss measurements and electrochemical methods, e.g., electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. The results obtained by GAD treatment show that the corrosion rate of steel decreases with the ennoblement of the corrosion potential and the decrease of the corrosion current density. This indicates that the plasma treatment acts as an anodic type inhibitor and suggests the formation of a protective layer. EIS measurements confirm the presence of this film: the charge transfer resistance (Rct) increases with GAD treatment time, leading to a corrosion inhibition efficiency around 73% for a treatment time equal to 60 min. This confirms the importance of the plasma effect. The gliding arc discharge is a clean and efficient technology for the surface treatment of carbon steel; it improves the anticorrosion properties of steel in aggressive environments, forming a resistant and insulating barrier.

Ghali, Noureddine; Addou, Ahmed; Mutel, Brigitte; Benstaali, Baghdad; Bentiss, Fouad; Brisset, Jean-Louis

2013-02-01