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1

Acetone to MIBK process optimization through multidisciplinary chemometrics and in-line NIR spectroscopy  

Microsoft Academic Search

A comprehensive experimental approach to the optimization of the process parameters for the production of methyl-isobutyl-ketone (MIBK) from acetone was developed and successfully implemented. This includes conventional laboratory analysis, in-line near infrared (NIR) spectroscopy (with associated principle component analysis) and statistical interpretation of the experimental results. The effect of temperature, pressure, feed rate and the H2 to acetone molar ratio

Nicolaas M. Prinsloo; J. Pirow Engelbrecht; Thomas N. Mashapa; Margaret J. Strauss

2008-01-01

2

Transient-state behavior of a biofilter removing mixtures of vapors of MEK and MIBK from air  

SciTech Connect

In the work reported here, selected aspects of the dynamic behavior of biofilters for waste air treatment have been investigated. Emphasis was placed on transient state elimination of mixtures of methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK) vapors and on explanation of the observed phenomena. The initial startup, the response of the biofilter to step changes in the pollutant loadings, responses to pollutant pulses, restarting after starvation, and the influence of step changes in gaseous phase oxygen partial pressure are presented and discussed.

Deshusses, M.A.; Hamer, G.; Dunn, I.J. [Swiss Federal Inst. of Tech., Zurich (Switzerland)] [Swiss Federal Inst. of Tech., Zurich (Switzerland)

1996-03-05

3

[{sup 14}C]pyrene bound residue evaluation using MIBK fractionation method for creosote-contaminated soil  

SciTech Connect

The fate of [{sup 14}C]pyrene was evaluated in creosote-contaminated soil undergoing remediation in a prepared bed system at the Champion International Superfund site in Libby, MT. {sup 14}C-bound residue formation was evaluated using the methyl isobutyl ketone (MIBK) humic fractionation procedure, and it increased through 294 days of incubation in biologically active microcosms for humic acid, fulvic acid, bound humic acid, and mineral-associated organic carbon fractions. The relative affinity of the added pyrene and transformation products was highest for the humic acid fraction. Bound residue formation in PAH-contaminated soil was observed to be an important fate mechanism in the prepared bed system and may be an acceptable end point in the remediation of contaminated soil.

Nieman, J.K.C.; Sims, R.C.; Sims, J.L.; Sorensen, D.L.; McLean, J.E. [Utah State Univ., Logan, UT (United States)] [Utah State Univ., Logan, UT (United States); Rice, J.A. [South Dakota State Univ., Brookings, SD (United States). Dept. of Chemistry and Biochemistry] [South Dakota State Univ., Brookings, SD (United States). Dept. of Chemistry and Biochemistry

1999-03-01

4

Methyl isobutyl ketone as a solvent for wax deoiling  

SciTech Connect

The solvency of methyl isobutyl ketone (MIBK) for use in deoiling and cold-fractionation of solid paraffin waxes is investigated by a visual polytherm method in the temperature interval 0-36 C. The capability of MIBK for precipitating solid hydrocarbons from solution was found to be greater than acetone/toluene or MEK/toluene, with only MEK better in this respect than MIBK. The quantity of wax remaining in the filtrate is examined. The critical solution temperatures are investigated and it is shown that MIBK surpasses MEK. The results obtained indicate that MIBK is extremely promising for use in processes of deoiling and cold fractionation of waxes.

Larikov, V.I.; Pereverzev, A.N.; Roshchin, Y.N.; Sokolova, S.P.

1983-09-01

5

Methyl isobutyl ketone as a solvent for wax deoiling  

Microsoft Academic Search

The solvency of methyl isobutyl ketone (MIBK) for use in deoiling and cold-fractionation of solid paraffin waxes is investigated by a visual polytherm method in the temperature interval 0-36 C. The capability of MIBK for precipitating solid hydrocarbons from solution was found to be greater than acetone\\/toluene or MEK\\/toluene, with only MEK better in this respect than MIBK. The quantity

V. I. Larikov; Yu. N. Roshchin; S. P. Sokolova; A. N. Pereverzev

1983-01-01

6

Cite this: RSC Advances, 2013, 3, Enhanced yields of furfural and other products by  

E-print Network

of 5 wt% solids in 0.1 M sulfuric or hydrochloric acid at 170 uC over a range of reaction times sulfuric or hydrochloric acid. However, the yield increased significantly to about 85.3% when MIBK extraction was employed in combination with sulfuric acid catalysis for 50 min, while combining MIBK

California at Riverside, University of

7

Toxicity and carcinogenicity of methyl isobutyl ketone in F344N rats and B6C3F1 mice following 2-year inhalation exposure  

Microsoft Academic Search

Methyl isobutyl ketone (MIBK) is primarily used as a denaturant for rubbing alcohol, as a solvent and in the manufacture of methyl amyl alcohol. Inhalation of vapors is the most likely route of exposure in the work place. In order to evaluate the potential of MIBK to induce toxic and carcinogenic effects following chronic exposure, groups of 50 male and

Matthew D. Stout; Ronald A. Herbert; Grace E. Kissling; Fernando Suarez; Joseph H. Roycroft; Rajendra S. Chhabra; John R. Bucher

2008-01-01

8

The removal of volatile ketone mixtures from air in biofilters  

Microsoft Academic Search

The work reported concerns the removal of mixtures of two ketones, methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK), which find wide application as industrial solvents, from effluent air streams in downward flow biofilters operating at relative humidities in excess of 95 percent. The inlet concentrations of the two pollutants were 300 mg m-3MEK and 330 mg m-3MIBK. Maximum

M. A. Deshusses; G. Hamer

1993-01-01

9

5-(2?-Carboxyphenyl)azo-8-quinolinol as a sensitive reagent for extractive spectrophotometric determination of uranium in geological samples  

Microsoft Academic Search

A new sensitive extractive spectrophotometric method has been suggested for the determination of uranium in soils, stream sediments and rock samples using 5-(2-carboxyphenyl)azo-8-quinolinol (R). Uranyl nitrate is extracted in isobutylmethyl ketone (MIBK) at pH 5.2–6.1 in presence of saturated ammonium nitrate solution. The aqueous solution of R is shaken with MIBK containing uranyl nitrate. R forms almost instantaneously an amber

R. Saran; N. K. Baishya

1995-01-01

10

Bifunctionalized hollow nanospheres for the one-pot synthesis of methyl isobutyl ketone from acetone.  

PubMed

Pd-doped propyl sulfonic acid-functionalized hollow nanospheres proved to be efficient bifunctionalized catalysts for the one-pot synthesis of methyl isobutyl ketone (MIBK) from acetone and hydrogen in liquid phase. These hollow nanospheres exhibited a higher activity than their bulk mesoporous counterparts (SBA-15 or FDU-12), mainly due to the short diffusion resistance of hollow nanospheres. Hollow nanospheres with silica frameworks showed higher activity and selectivity for MIBK than those with ethane-bridged frameworks, suggesting that hollow nanospheres with hydrophilic surface properties favor the formation of MIBK. This is probably due to the increased affinity of the hydrophilic surface towards acetone and its decreased affinity towards MIBK, which precludes deep condensation of MIBK with acetone. Under optimal conditions, up to 90 % selectivity for MIBK can be obtained with conversions of acetone as high as 43 %. This result is among the best reported so far for mesoporous silica-based catalysts. The control/fine-tuning of morphology and surface properties provides an efficient strategy for improving the catalytic performance of solid catalysts. PMID:23132691

Wang, Peng; Bai, Shiyang; Zhao, Jiao; Su, Panpan; Yang, Qihua; Li, Can

2012-12-01

11

Solvent extraction of phenols from water  

SciTech Connect

Methyl isobutyl ketone (MIBK) and diisopropyl ether (DIPE) have been evaluated as solvents for extraction of phenols, at high dilution, from water. Equilibrium distribution coefficients (K/sub D/) have been measured for phenol, dihydroxybenzenes and trihydroxybenzenes in both solvents as a function of pH. Particularly for the multihydric phenols, MIBK gives substantially higher values of K/sub D/ than does DIPE. The effect of pH can be described quantitatively through a simple ionization model, using published values of dissociation constants for the various phenols. Some method for removal of residual dissolved solvent must ordinarily be included in any extraction process for phenols. Possibilities include atmospheric-steam or inert-gas stripping, vacuum-steam stripping, and extraction with a second solvent. Vacuum-steam stripping is a particularly attractive choice for removal of MIBK; this reinforces the utility of MIBK as a solvent. The optimal temperature for vacuum stripping is generally the temperature of the extraction operation, which in turn is related to the effect of temperature on K/sub D/. Values of K/sub D/ for phenol-water-MIBK were determined at 30, 50, and 75/sup 0/C, and were found to decrease with increasing temperature at all concentrations.

Greminger, D.C.; Burns, G.P.; Lynn, S.; Hanson, D.H.; King, C.J.

1980-02-01

12

Treatment of biomass gasification wastewaters using liquid-liquid extraction  

SciTech Connect

Pacific Northwest Laboratory (PNL) investigated liquid-liquid extraction as a treatment method for biomass gasification wastewaters (BGW). Distribution coefficients for chemical oxygen demand (COD) removal were determined for the following solvents: methylisobutyl ketone (MIBK), n-butyl acetate, n-butanol, MIBK/n-butyl acetate (50:50 vol), MIBK/n-butanol (50:50 vol), tri-butyl phosphate, tri-n-octyl phosphine oxide (TOPO)/MIBK (10:90 wt), TOPO/kerosene (10:90 wt), kerosene, and toluene. The best distribution coefficient of 1.3 was given by n-butanol. Chemical analysis of the wastewater by gas chromatography (GC) showed acetic acid and propionic acid concentrations of about 4000 mg/1. Methanol, ethanol, and acetone were identified in trace amounts. These five compounds accounted for 45% of the measured COD of 29,000 mg/1. Because of the presence of carboxylic acids, pH was expected to affect extraction of the wastewater. At low pH the acids should be in the acidic form, which increased extraction by MIBK. Extraction by n-butanol was increased at high pH, where the acids should be in the ionic form.

Bell, N.E.

1981-09-01

13

Determination of silver in soils, sediments, and rocks by organic-chelate extraction and atomic absorption spectrophotometry  

USGS Publications Warehouse

A useful method for the determination of silver in soil, sediment, and rock samples in geochemical exploration has been developed. The sample is digested with concentrated nitric acid, and the silver extracted with triisooctyl thiophosphate (TOTP) in methyl isobutyl ketone (MIBK) after dilution of the acid digest to approximately 6 M. The extraction of silver into the organic extractant is quantitative and not affected by the nitric acid concentration from 4 M to 8 M, or by different volumes of TOTP-MIBK. The extracted silver is stable and remains in the organic phase up to several days. The silver concentration is determined by atomic absorption spectrophotometry. ?? 1971.

Chao, T.T.; Ball, J.W.; Nakagawa, H.M.

1971-01-01

14

Chiroptical hot spots in twisted nanowire plasmonic oscillators  

E-print Network

to prevent sample charging during the e-beam writing process. 1 to whom correspondence should be addressed:3 MIBK:IPA for 40 s, yielding wire-shaped grooves in the PMMA. Metal was deposited via thermal the pushing lens and the top substrate, immersion oil (Cargille Labs, type FF) was applied at this interface

Cohen, Adam E.

15

Manganese dioxide causes spurious gold values in flame atomic-absorption readings from HBr-Br2 digestions  

USGS Publications Warehouse

False readings, apparently caused by the presence of high concentrations of manganese dioxide, have been observed in our current flame atomic-absorption procedure for the determination of gold. After a hydrobromic acid (HBr)-bromine (Br2) leach, simply heating the sample to boiling to remove excess Br2 prior to extraction with methyl-isobutyl-ketone (MIBK) eliminates these false readings. ?? 1981.

Campbell, W.L.

1981-01-01

16

Criteria for One-Dimensional Transport in Split-Gate Field-Effect Transistors Cristopher C. Eugster, JesGs A. del Alamo, Paul A. Belk and Michael J. Rooks'  

E-print Network

[I].If a modulation- doped FET (MODFET) semiconductor structure is designed normally on or depletion voltage depletes the 2D electron gas (2DEG) underneath the gates but leaves a narrow con- ducting channel. Two molecular weights of PMMA were cast in solu- tions of MIBK (methylisobutylketone), in a process

del Alamo, Jesús A.

17

Effects of unsteady state conditions on the biooxidation of methyl ethyl and methyl isobutyl ketone in continuous flow liquid phase cultures  

E-print Network

in continuous flow liquid phase cultures D.P. Geoghegan, G. Hamer, M.A. Deshusses Abstract The effects liquid waste streams. Both MEK and MIBK have been designated high-priority toxic chemicals [2] in spite, but details of the kinetics of such biodegradation processes are scant, particularly in liquid phase cultures

18

Performance of PDMS and organofunctionalised PDMS membranes for the pervaporative recovery of organics from aqueous streams  

Microsoft Academic Search

Modified polysiloxane membranes containing different organofunctional side chains were produced and tested for the recovery of various organic contaminants from aqueous sterams, using the process of pervaporation. Four separate organic components, phenol, chloroform, pyridine and methylisobutylketone (MIBK), each representative of an industrially significant family of chemicals, were chosen for evaluation. In each case significant performance enhancements, over that achieved with

M. Bennett; B. J. Brisdon; R. England; R. W. Field

1997-01-01

19

Evaluation of solvent selectivity in dewaxing and deoiling  

Microsoft Academic Search

Previous literature on the efficiency of solvents used in removing paraffin wax by decrystallization is insufficient. A method for evaluating selectivity and mixtures of solvents is offered. General solvents MEK, acetone, MIBK are tested in various raw materials, then graphed. It is found that the ratio of the slope of the curve for the temperature of equal solubility (TES) as

N. V. Alperovich; A. N. Leonidov; S. P. Sokolova

1983-01-01

20

Flame and flameless atomic-absorption determination of tellurium in geological materials  

USGS Publications Warehouse

The sample is digested with a solution of hydrobromic acid and bromine and the excess of bromine is expelled. After dilution of the solution to approximately 3 M in hydrobromic acid, ascorbic acid is added to reduce iron(III) before extraction of tellurium into methyl isobutyl ketone (MIBK). An oxidizing air-acetylene flame is used to determine tellurium in the 0.1-20 ppm range. For samples containing 4-200 ppb of tellurium, a carbon-rod atomizer is used after the MIBK extract has been washed with 0.5 M hydrobromic acid to remove the residual iron. The flame procedure is useful for rapid preliminary monitoring, and the flameless procedure can determine tellurium at very low concentrations. ?? 1978.

Chao, T.T.; Sanzolone, R.F.; Hubert, A.E.

1978-01-01

21

SML resist processing for high-aspect-ratio and high-sensitivity electron beam lithography  

NASA Astrophysics Data System (ADS)

A detailed process characterization of SML electron beam resist for high-aspect-ratio nanopatterning at high sensitivity is presented. SML contrast curves were generated for methyl isobutyl ketone (MIBK), MIBK/isopropyl alcohol (IPA) (1:3), IPA/water (7:3), n-amyl acetate, xylene, and xylene/methanol (3:1) developers. Using IPA/water developer, the sensitivity of SML was improved considerably and found to be comparable to benchmark polymethylmethacrylate (PMMA) resist without affecting the aspect ratio performance. Employing 30-keV exposures and ultrasonic IPA/water development, an aspect ratio of 9:1 in 50-nm half-pitch dense grating patterns was achieved representing a greater than two times improvement over PMMA. Through demonstration of 25-nm lift-off features, the pattern transfer performance of SML is also addressed.

Mohammad, Mohammad Ali; Dew, Steven K.; Stepanova, Maria

2013-03-01

22

An evaluation of the 3M Organic Vapor Monitor #3500 as a short term exposure limit sampling device for acetone, methyl ethyl ketone, and methyl iso butyl ketone  

E-print Network

of Advisory Committee: Col. Harry J. Suggs The 3M organic vapor monitors were investigated. for their use in monitoring a short term exposure limit (STEL) of Acetone, MEK, and MIBK. The monitors were also investigated to see if one monitor used to measure... three sequential STEL's collected the same amount of contaminant as monitors exposed to each STEL separately. The monitors were exposed to the contaminant in a closed system. Analysis of the monitors was done using a gas chromatograph...

Andrew, Lloyd B.

1982-01-01

23

Simultaneous Determination of Trace Heavy Metals in Waters by Atomic Absorption Spectrometry After Preconcentration by Solvent Extraction  

Microsoft Academic Search

A simple and rapid method for the simultaneous extraction of heavy metals using a new reagent 5-(2?-carbomethoxyphenyl; azo-8-quinolinol(R) into methyl isobutyl. ketone (MIBK) and their subsequent determination by flame atomic absorption spectrometry is described. The method has been applied to the determination of Cu. Pb, Ni, Fe, Cr, Co and Mo in drinking and bore well waters. The extraction has

R. Saran; T. S. Basu Baul; P. Srinivas; D. T. Khathing

1992-01-01

24

Rheological behaviour of BaZrO 3 suspensions in non-aqueous media  

Microsoft Academic Search

The colloidal behaviour of concentrated non-aqueous suspensions of barium zirconate is investigated. Optimum dispersing conditions are investigated for organic suspensions prepared with different solvent systems: methylethylketone (MEK)\\/ethanol, trichloroethylene (TCE)\\/ethanol, a methylisobutylketone (MIBK)\\/methylethylketone\\/cyclohexanone (CHN) and pure ethanol. Stabilisation of the suspensions is achieved by using two different dispersants: ester phosphate (EPH) and Hypermer KD-6. Rheological studies have been made in order

F. Boschini; A. Rulmont; R. Cloots; R. Moreno

2009-01-01

25

Comparative Efficiencies of Trace Metal Extraction from Municipal Incinerator Ashes  

Microsoft Academic Search

Five laboratory solvent extraction methods for the determination of leachable trace metals from municipal incinerator fly and bottom ashes are evaluated. The trace elements of interest were cadmium, chromium, copper, manganese and lead. Five different extractants, 0.1NHCl, 1.0 N ammonium acetate, methyl isobutyl ketone (MIBK), chloroform and hexane were used on each ash to determine comparative extraction efficiencies.Extraction efficiencies of

C. A. Cahill; L. W. Newland

1982-01-01

26

Electrical Conductivity Response toward Ketone Vapors of Poly(Para-Phenylene Vinylene)/Zeolite Y Composites  

NASA Astrophysics Data System (ADS)

Investigation of the effect of 3 different types of cation types in Zeolite Y; Zeolite Y(Si/Al=5.1, Na+), Zeolite Y(Si/Al=5.1, NH3+), Zeolite Y(Si/Al=5.1, H+) on the electrical conductivity sensitivity when exposed to the 3 different types of ketone vapors (Acetone, Methyl Ethyl Ketone(MEK) and Methyl Iso Buthyl Ketone(MIBK)), which are flammable and toxic components in order to improve the selectivity and sensitivity of dPPV/Zeolite Y and the interactions between the ketone molecules and the composites with respect to the electrical conductivity sensitivity are investigated though the infrared spectroscopy(FTTIR). All composites show definite positive responses towards the ketone vapors (Acetone, Methyl Ethyl Ketone (MEK), Methyl Iso-Buthyl Ketone (MIBK)). The electrical conductivity sensitivities of the composites increase linearly with increasing surface area of the Zeolite Y. The highest electrical conductivity sensitivity is obtained with the dPPV_/Zeolite Y (Si/Al = 5.1, NH4+), higher than those of dPPV_/Zeolite Y (Si/Al = 5.1, Na+) and dPPV_/Zeolite Y (Si/Al = 5.1, H+) when exposed to acetone. Amongst the Ketone vapors, acetone induces the highest electrical conductivity sensitivity, whereas MIBK induces the lowest electrical conductivity sensitivity.

Kamonsawas, Jirarat; Sirivat, Anuvat

2012-02-01

27

Determination of traces of silver in waters by anion exchange and atomic absorption spectrophotometry  

USGS Publications Warehouse

A method has been developed for the accurate determination of 0.1-1 ??g of silver per liter of water. The method permits stabilization of silver in water without loss to container walls. Optimum conditions have been established for the complete recovery of silver from water with an anion-exchange column, for quantitative elution of silver from the resin, and for measurement of silver by atomic absorption spectrophotometry after chelation with ammonium pyrrolidine dithiocarbamate and extraction of the chelate with MIBK. Silver in the 1-10 ??g 1 range can be determined by extraction without pre-concentration on an ion-exchange resin. ?? 1969.

Chao, T.T.; Fishman, M.J.; Ball, J.W.

1969-01-01

28

Purification of biomass-derived 5-hydroxymethylfurfural and its catalytic conversion to 2,5-furandicarboxylic Acid.  

PubMed

A simple and effective water extraction method is presented for the purification 5-hydroxylmethylfurfural (HMF) obtained from a biomass dehydration system. Up to 99% of the HMF can be recovered and the HMF in aqueous solution is directly converted to 2,5-furandicarboxylic acid (FDCA) as the sole product. This purification technique allows an integrated process to produce FDCA from fructose via HMF prepared in an isopropanol monophasic system, with an overall FDCA yield of 83% obtained. From Jerusalem raw artichoke biomass to FDCA via HMF prepared in a water/MIBK (methyl isobutyl ketone) biphasic system, an overall FDCA yield of 55% is obtained. PMID:24889713

Yi, Guangshun; Teong, Siew Ping; Li, Xiukai; Zhang, Yugen

2014-08-01

29

Severe cutaneous reaction to CS gas.  

PubMed

Tear gas is used throughout the World for control of riots and civil disobedience. CS gas as used by the UK police force is issued as a 'spray' and is 5% CS in methylisobutylketone (MIBK), a potent irritant. Assaults on police officers in forces issued with CS spray have fallen significantly over the past 3 years, whilst having risen in areas without it. Thus, CS gas appears to be an effective deterrent. However, significant cutaneous reactions can occur as a result of exposure. We report a severe contact dermatitis to CS gas to highlight the clinical features. The nature of CS gas and potential cutaneous adverse reactions are discussed. PMID:11422166

Varma, S; Holt, P J

2001-05-01

30

Evaluation of solvent selectivity in dewaxing and deoiling  

SciTech Connect

Previous literature on the efficiency of solvents used in removing paraffin wax by decrystallization is insufficient. A method for evaluating selectivity and mixtures of solvents is offered. General solvents MEK, acetone, MIBK are tested in various raw materials, then graphed. It is found that the ratio of the slope of the curve for the temperature of equal solubility (TES) as a function of the content of the solvent (that is, the solubility curve) to the slope of the corresponding denormalization curve is constant. This ratio gives a formula, and is therefore a criterion for selectivity. The greater the ratio, the higher the selectivity. The ratio is also generalized to solvents of any composition.

Al'perovich, N.V.; Leonidov, A.N.; Sokolova, S.P.

1983-05-01

31

Determination of total tin in silicate rocks by graphite furnace atomic absorption spectrometry  

USGS Publications Warehouse

A method is described for the determination of total tin in silicate rocks utilizing a graphite furnace atomic absorption spectrometer with a stabilized-temperature platform furnace and Zeeman-effect background correction. The sample is decomposed by lithium metaborate fusion (3 + 1) in graphite crucibles with the melt being dissolved in 7.5% hydrochloric acid. Tin extractions (4 + 1 or 8 + 1) are executed on portions of the acid solutions using a 4% solution of tricotylphosphine oxide in methyl isobutyl ketone (MIBK). Ascorbic acid is added as a reducing agent prior to extraction. A solution of diammonium hydrogenphosphate and magnesium nitrate is used as a matrix modifier in the graphite furnace determination. The limit of detection is > 10 pg, equivalent to > 1 ??g l-1 of tin in the MIBK solution or 0.2-0.3 ??g g-61 in the rock. The concentration range is linear between 2.5 and 500 ??g l-1 tin in solution. The precision, measured as relative standard deviation, is < 20% at the 2.5 ??g l-1 level and < 7% at the 10-30 ??g l-1 level of tin. Excellent agreement with recommended literature values was found when the method was applied to the international silicate rock standards BCR-1, PCC-1, GSP-1, AGV-1, STM-1, JGb-1 and Mica-Fe. Application was made to the determination of tin in geological core samples with total tin concentrations of the order of 1 ??g g-1 or less.

Elsheimer, H.N.; Fries, T.L.

1990-01-01

32

Transient behavior of biofilters: Start-up, carbon balances, and interactions between pollutants  

SciTech Connect

The work describes the aerobic biodegradation of volatile organic compound (VOC) mixtures from effluent air streams in laboratory-scale compost based biofilters. A rapid start-up of the system (3--5 d) was observed and 82% of the carbon in the influent pollutant (methyl ethyl ketone) was recovered as carbon dioxide in the exhaust air after this period. Biofilter performance and carbon dioxide production were also investigated during and after 0.5--1-h step inputs of 2--10 g m{sup {minus}3} of hexane, acetone, 1-propanol, and/or methyl isobutyl ketone (MIBK) during steady methyl ethyl ketone (MEK) treatment. Carbon dioxide patterns suggest that pulsed pollutants were first sorbed onto the packing material and subsequently degraded within 2--5 h. Hexane was not sorbed, and thus not degraded to a significant extent. Little effect was observed of the step inputs on the overall MEK removal process, mainly because the reactors were operated well below MEK breakthrough loading. However, the analysis of MEK profiles within the biofilter bed showed that significant inhibition did indeed occur. An even more important inhibition was observed between 1-propanol, MIBK, and acetone, when such a mixture was injected into the reactor. Practical design of biofilters should consider the possibility of reduced performances due to the presence of multiple VOCs in the waste air stream.

Deshusses, M.A. [Univ. of California, Riverside, CA (United States). Coll. of Engineering

1997-06-01

33

Fourth derivative spectrophotometric determination of fungicide thiram (tetramethyldithiocarbamate) using sodium molybdate and its application.  

PubMed

A procedure has been developed for the direct fourth derivative spectrophotometric determination of tetramethyldithiocarbamate by converting it into its molybdenum complex, which is then extracted in to methyl isobutyl ketone (MIBK). Beer's law is obeyed over the concentration range 24mugmL(-1) in the final solution. The analytical sensitivity is calculated to be 0.004(d(4)A/dlambda(4)) mug(-1)mL(-1) from the slope of the calibration curve. The detection limit is 0.3mugmL(-1) for thiram (signal to noise ratio = 2). Various parameters, such as effect of acid concentration, interference of a large number of ions in the determination of thiram have been studied in detail. The method is sensitive, highly selective and can be used for the determination of thiram in a commercial sample, in mixtures with various dithiocarbamates (zineb, maneb, etc.) and from wheat grains. PMID:18969809

Sharma, Vaneet Kumar; Aulakh, J S; Malik, A K

2005-01-30

34

Development of a test method for carbonyl compounds from stationary source emissions  

SciTech Connect

Carbonyl compounds have received increasing attention because of their important role in ground-level ozone formation. The common method used for the measurement of aldehydes and ketones is 2,4-dinitrophenylhydrazine (DNPH) derivatization followed by high performance liquid chromatography and ultra violet (HPLC-UV) analysis. One of the problems associated with this method is the low recovery for certain compounds such as acrolein. This paper presents a study in the development of a test method for the collection and measurement of carbonyl compounds from stationary source emissions. This method involves collection of carbonyl compounds in impingers, conversion of carbonyl compounds to a stable derivative with O-2,3,4,5,6-pentafluorobenzyl hydroxylamine hydrochloride (PFBHA), and separation and measurement by electron capture gas chromatography (GC-ECD). Eight compounds were selected for the evaluation of this method: formaldehyde, acetaldehyde, acrolein, acetone, butanal, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and hexanal.

Zhihua Fan; Peterson, M.R.; Jayanty, R.K.M. [Research Triangle Institute, Research Triangle Park, NC (United States)

1997-12-31

35

Determination of silver, bismuth, cadmium, copper, lead, and zinc in geologic materials by atomic absorption spectrometry with tricaprylylmethylammonium chloride  

USGS Publications Warehouse

Interferences commonly encountered in the determination of silver, bismuth, cadmium, copper, lead, and zinc at crustal abundance levels are effectively eliminated using a rapid, sensitive, organic extraction technique. A potassium chlorate-hydrochloric acid digestion solubilizes the metals not tightly bound in the silicate lattice of rocks, soils, and stream sediments. The six metals are selectively extracted into a 10% Aliquat 336-MIBK organic phase in the presence of ascorbic acid and potassium iodide. Metals in the organic extract are determined by flame atomic absorption spectrometry to the 0.02-ppm level for silver, cadmium, copper, and zinc and to the 0.2-ppm level for bismuth and lead with a maximum relative standard deviation of 18.8% for known reference samples. An additional hydrofluoric acid digestion may be used to determine metals substituted in the silicate lattice.

Viets, J.G.

1978-01-01

36

Determination of trace amounts of tin in geological materials by atomic absorption spectrometry  

USGS Publications Warehouse

An atomic absorption method is described for the determination of traces of tin in rocks, soils, and stream sediments. A dried mixture of the sample and ammonium iodide is heated to volatilize tin tetraiodide -which is then dissolved in 5 % hydrochloric acid, extracted into TOPO-MIBK, and aspirated into a nitrous oxide-acetylene flame. The limit of determination is 2 p.p.m. tin and the relative standard deviation ranges from 2 to 14 %. Up to 20 % iron and 1000 p.p.m. Cu, Pb, Zn, Mn, Hg, Mo, V, or W in the sample do not interfere. As many as 50 samples can be easily analyzed per man-day. ?? 1976.

Welsch, E.P.; Chao, T.T.

1976-01-01

37

The determination of vanadium in brines by atomic absorption spectroscopy  

USGS Publications Warehouse

A standard addition method is described for the determination of vanadium in brines by atomic absorption spectroscopy with a nitrous oxide-acetylene flame. Sample pH is adjusted to 1.0 with concentrated hydrochloric acid and the vanadium is directly extracted with 5% cupferron in methyl isobutyl ketone (MIBK). The ketone layer is then aspirated into the flame and the recorded absorption values are plotted as a function of the concentration of the added metal. As little as 2.5 ??g l-1 of vanadium can be detected under the conditions of the procedure. Tungsten and tin interfere when present in excess of 5 and 10 ??g ml-1, respectively. The concentrations of the two interfering ions normally found in brines are well below interference levels. ?? 1971.

Crump-Wiesner, H. J.; Feltz, H.R.; Purdy, W.C.

1971-01-01

38

Investigative study on alcohol diesel fuel blends. Final report 1 Oct 80-30 Jun 81  

SciTech Connect

The project involved characterization, storage stability and material compatibility studies of ethanol and 2 diesel fuels. Ten samples of commercially available fuels were obtained and blended with 10% ethanol which was denatured with gasolene and a solvent blend of ethyl acetate and MIBK. Anhydrous alcohol also was used to prepare a 10% blend to examine stability and material compatibility characteristics. It has been observed that the presence of small amounts of water in the alcohol causes phase Separation and great care must be taken to prevent water contamination in the fuel system. It has also been found that certain surfactants and co-solvents would stabilize the fuel blends even when water is present in the blended fuels. Results of test on stability and material compatibility are presented in this report.

Pandalai, K.; Ayoub, A.; Pandalai, B.

1981-06-01

39

Cobalt content of foods and diets in a Spanish population (short communication).  

PubMed

The WHO Expert Committee on Food Contaminants has pointed out the need of determining the content of foods in trace elements in order to ascertain their contribution to the total intake of oligoelements through the diet. Since the contents in trace elements depend on the environmental features, it is necessary to carry out systematic determinations of trace elements in foods of local origin in order to know the exposure level of population. This work intends to study the cobalt contribution through the diet. The element intake is calculated from the cobalt content in raw foods after elimination of the non-eatable moiety by flame atomic absorption spectroscopy, after formation of a chelate with ammonium pyrrolidine dithiocarbamate (APDC) and extraction with 4-methyl-2-pentanone (MIBK) according to a procedure developed and verified in a previous paper. PMID:3748133

Barberá, R; Farré, R

1986-01-01

40

Selective and recyclable depolymerization of cellulose to levulinic acid catalyzed by acidic ionic liquid.  

PubMed

Cellulose depolymerization to levulinic acid (LA) was catalyzed by acidic ionic liquids (ILs) selectively and recyclably under hydrothermal conditions. The effects of reaction temperature, time, water amount and cellulose intake were investigated. Dilution effect becomes more pronounced at lower cellulose intake, dramatically improving the yield of LA to 86.1%. A kinetic model has been developed based on experimental data, whereby a good fit was obtained and kinetic parameters were derived. The relationships between IL structure, polymeric structure and depolymerization efficiency were established, shedding light on the in-depth catalytic mechanism of IL, inclusive of acidity and hydrogen bonding ability. The LA product can be readily separated through extraction by methyl isobutyl ketone (MIBK) and IL can be reused over five cycles without loss of activity. This environmentally friendly methodology can be applied to selective production of LA from versatile biomass feedstocks, including cellulose and derivatives, glucose, fructose and HMF. PMID:25498672

Ren, Huifang; Girisuta, Buana; Zhou, Yonggui; Liu, Li

2015-03-01

41

Superfund record of decision (EPA Region 10): Teledyne Wah Chang Albany Site, Millersburg, OR, June 1994  

SciTech Connect

This decision document presents the selected remedial actions for the Teledyne Wah Chang Albany Site (Site or TWCA Site), in Millersburg, Linn County, Oregon. The remedial actions described below are the final response actions planned for the groundwater and sediments operable unit at the Site. Teledyne Wah Chang Albany is an active operating facility which primarily manufactures zirconium metal from zircon sands. The processing of the zircon sands generates sludge, waste water, residues and gases as by-products. The cleanup actions described in this ROD address the threats to groundwater and sediment posed by radionuclides, metals, polychlorinated biphenyls (PCBs), methyl isobutyl ketone (MIBK), thrichloroethylene, tetrachloroethylene, 1,1,1-trichloroethane, and other contaminants at the Site.

Not Available

1994-06-10

42

Evaluation of performance impairment by spacecraft contaminants  

NASA Technical Reports Server (NTRS)

The environmental contaminants (isolated as off-gases in Skylab and Apollo missions) were evaluated. Specifically, six contaminants were evaluated for their effects on the behavior of juvenile baboons. The concentrations of contaminants were determined through preliminary range-finding studies with laboratory rats. The contaminants evaluated were acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), trichloroethylene (TCE), heptane and Freon 21. When the studies of the individual gases were completed, the baboons were also exposed to a mixture of MEK and TCE. The data obtained revealed alterations in the behavior of baboons exposed to relatively low levels of the contaminants. These findings were presented at the First International Symposium on Voluntary Inhalation of Industrial Solvents in Mexico City, June 21-24, 1976. A preprint of the proceedings is included.

Geller, I.; Hartman, R. J., Jr.; Mendez, V. M.

1977-01-01

43

Determination of gold, indium, tellurium and thallium in the same sample digest of geological materials by atomic-absorption spectroscopy and two-step solvent extraction  

USGS Publications Warehouse

A rock, soil, or stream-sediment sample is decomposed with hydrofluoric acid, aqua regia, and hydrobromic acid-bromine solution. Gold, thallium, indium and tellurium are separated and concentrated from the sample digest by a two-step MIBK extraction at two concentrations of hydrobromic add. Gold and thallium are first extracted from 0.1M hydrobromic acid medium, then indium and tellurium are extracted from 3M hydrobromic acid in the presence of ascorbic acid to eliminate iron interference. The elements are then determined by flame atomic-absorption spectrophotometry. The two-step solvent extraction can also be used in conjunction with electrothermal atomic-absorption methods to lower the detection limits for all four metals in geological materials. ?? 1985.

Hubert, A.E.; Chao, T.T.

1985-01-01

44

A Bio-Catalytic Approach to Aliphatic Ketones  

PubMed Central

Depleting oil reserves and growing environmental concerns have necessitated the development of sustainable processes to fuels and chemicals. Here we have developed a general metabolic platform in E. coli to biosynthesize carboxylic acids. By engineering selectivity of 2-ketoacid decarboxylases and screening for promiscuous aldehyde dehydrogenases, synthetic pathways were constructed to produce both C5 and C6 acids. In particular, the production of isovaleric acid reached 32 g/L (0.22 g/g glucose yield), which is 58% of the theoretical yield. Furthermore, we have developed solid base catalysts to efficiently ketonize the bio-derived carboxylic acids such as isovaleric acid and isocaproic acid into high volume industrial ketones: methyl isobutyl ketone (MIBK, yield 84%), diisobutyl ketone (DIBK, yield 66%) and methyl isoamyl ketone (MIAK, yield 81%). This hybrid “Bio-Catalytic conversion” approach provides a general strategy to manufacture aliphatic ketones, and represents an alternate route to expanding the repertoire of renewable chemicals. PMID:22416247

Xiong, Mingyong; Deng, Jin; Woodruff, Adam P.; Zhu, Minshan; Zhou, Jun; Park, Sun Wook; Li, Hui; Fu, Yao; Zhang, Kechun

2012-01-01

45

The determination of specific forms of aluminum in natural water  

USGS Publications Warehouse

A procedure for analysis and pretreatment of natural-water samples to determine very low concentrations of Al is described which distinguishes the rapidly reacting equilibrium species from the metastable or slowly reacting macro ions and colloidal suspended material. Aluminum is complexed with 8-hydroxyquinoline (oxine), pH is adjusted to 8.3 to minimize interferences, and the aluminum oxinate is extracted with methyl isobutyl ketone (MIBK) prior to analysis by atomic absorption. To determine equilibrium species only, the contact time between sample and 8-hydroxyquinoline is minimized. The Al may be extracted at the sample site with a minimum of equipment and the MIBK extract stored for several weeks prior to atomic absorption analysis. Data obtained from analyses of 39 natural groundwater samples indicate that filtration through a 0.1-??m pore size filter is not an adequate means of removing all insoluble and metastable Al species present, and extraction of Al immediately after collection is necessary if only dissolved and readily reactive species are to be determined. An average of 63% of the Al present in natural waters that had been filtered through 0.1-??m pore size filters was in the form of monomeric ions. The total Al concentration, which includes all forms that passed through a 0.1-??m pore size filter, ranged 2-70 ??g/l. The concentration of Al in the form of monomeric ions ranged from below detection to 57 ??g/l. Most of the natural water samples used in this study were collected from thermal springs and oil wells. ?? 1975.

Barnes, R.B.

1975-01-01

46

Recovery of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) from Ralstonia eutropha cultures with non-halogenated solvents.  

PubMed

Reduced downstream costs, together with high purity recovery of polyhydroxyalkanoate (PHA), will accelerate the commercialization of high quality PHA-based products. In this work, a process was designed for effective recovery of the copolymer poly(hydroxybutyrate-co-hydroxyhexanoate) (P(HB-co-HHx)) containing high levels of HHx (>15?mol%) from Ralstonia eutropha biomass using non-halogenated solvents. Several non-halogenated solvents (methyl isobutyl ketone, methyl ethyl ketone, and butyl acetate and ethyl acetate) were found to effectively dissolve the polymer. Isoamyl alcohol was found to be not suitable for extraction of polymer. All PHA extractions were performed from both dry and wet cells at volumes ranging from 2?mL to 3?L using a PHA to solvent ratio of 2% (w/v). Ethyl acetate showed both high recovery levels and high product purities (up to 99%) when using dry cells as starting material. Recovery from wet cells, however, eliminates a biomass drying step during the downstream process, potentially saving time and cost. When wet cells were used, methyl isobutyl ketone (MIBK) was shown to be the most favorable solvent for PHA recovery. Purities of up to 99% and total recovery yields of up to 84% from wet cells were reached. During polymer recovery with either MIBK or butyl acetate, fractionation of the extracted PHA occurred, based on the HHx content of the polymer. PHA with higher HHx content (17-30?mol%) remained completely in solution, while polymer with a lower HHx content (11-16?mol%) formed a gel-like phase. All PHA in solution could be precipitated by addition of threefold volumes of n-hexane or n-heptane to unfiltered PHA solutions. Effective recycling of the solvents in this system is predicted due to the large differences in the boiling points between solvent and precipitant. Our findings show that two non-halogenated solvents are good candidates to replace halogenated solvents like chloroform for recovery of high quality PHA. PMID:22903730

Riedel, Sebastian L; Brigham, Christopher J; Budde, Charles F; Bader, Johannes; Rha, Chokyun; Stahl, Ulf; Sinskey, Anthony J

2013-02-01

47

Sensitive assay for oxygen solubility in molten alkali metal carbonates by indirect flame atomic absorption spectrometric Cr(VI) determination.  

PubMed

A precise and accurate indirect analytical method for the assessment of O(2) solubility in molten (Li(0.62)K(0.38))(2)CO(3) and (Li(0.52)Na(0.48))(2)CO(3) is described. The method is based on the oxidation of Cr(2)(SO(4))(3) (added in excess to the melt) by the oxygenate species, which are formed inside the melt when it is in contact with oxygen gas, and subsequent determination of trace amount of Cr(VI) in withdrawn frozen melts by flame atomic absorption spectrometry (FAAS). The samples (1.0-2.0g) are dissolved in dilute hydrochloric acid at room temperature. The speciation of Cr(VI) is carried out by complexation with ammonium pyrrolidine dithiocarbamate (APDC), followed by extraction into methyl isobutyl ketone (MIBK), which is introduced directly into the flame. Optimisation of the flame composition provided maximum Cr signal in organic phase under lean acetylene-air flame. The separation and preconcentration parameters such as sample volume/extractant volume ratio, pH sample solution, chelating concentration and extraction time are evaluated. Under the optimised conditions Cr(VI) is efficiently separated from Cr(III), which exceeded 200-folds. The results of the analysis of synthetic samples using standards in MIBK medium give rise to recoveries of 98-99%. The Cr(VI) detection limit of 4x10(-6)gL(-1) using 12.5-fold preconcentration and relative standard deviation of 1% at the 0.10mgL(-1) level are obtained. The sampling-to-sampling reproducibility was typically 3-5% relative standard deviation. By changing the preconcentration factor and the dilution of the sample melt, it is possible to analyse oxygen concentrations in molten alkali metal carbonates as low as 1.5x10(-9)mol O(2) per gram melt. PMID:18969674

Scaccia, Silvera; Frangini, Stefano

2004-10-20

48

Determination of dissolved aluminum in water samples  

USGS Publications Warehouse

A technique has been modified for determination of a wide range of concentrations of dissolved aluminum (Al) in water and has been tested. In this technique, aluminum is complexed with 8-hydroxyquinoline at pH 8.3 to minimize interferences, then extracted with methyl isobutyl ketone (MIBK). The extract is analyzed colorimetrically at 395 nm. This technique is used to analyze two forms of monomeric Al, nonlabile (organic complexes) and labile (free, Al, Al sulfate, fluoride and hydroxide complexes). A detection limit 2 ug/L is possible with 25-ml samples and 10-ml extracts. The detection limit can be decreased by increasing the volume of the sample and (or) decreasing the volume of the methyl isobutyl ketone extract. The analytical uncertainty of this method is approximately + or - 5 percent. The standard addition technique provides a recovery test for this technique and ensures precision in samples of low Al concentrations. The average percentage recovery of the added Al plus the amount originally present was 99 percent. Data obtained from analyses of filtered standard solutions indicated that Al is adsorbed on various types of filters. However, the relationship between Al concentrations and adsorption remains linear. A test on standard solutions also indicated that Al is not adsorbed on nitric acid-washed polyethylene and polypropylene bottle wells. (USGS)

Afifi, A.A.

1983-01-01

49

Kinetics of OH-initiated oxidation of some oxygenated organic compounds in the aqueous phase under tropospheric conditions  

NASA Astrophysics Data System (ADS)

The interest for multiphase interactions of Volatile Organic Compounds (VOCs) in the troposphere has increased for a few years. Inside the clouds water droplets, soluble VOCs can be oxidized by free radicals thus modifying the droplet composition. This reactivity has an impact on the tropospheric oxidizing capacity as well as the aerosols' properties. In the present work, we measured aqueous phase OH-initiated oxidation rate constants of several oxygenated organic compounds relevant to the atmosphere or chosen as test compounds (ethanol, t-butanol, 1-butanol, iso-propanol, 1-propanol, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, phenol, ethyl ter-butyl ether (ETBE), n-propyl acetate, acetone, methyl ethyl ketone (MEK), methyl iso-butyl ketone (MIBK), ethyl formate). Experiments took place in an aqueous phase photoreactor. The rate constants were determinated using the relative kinetic method. Different OH-radical sources were tested, as well as different reference compounds in order to detect any artifact. The results have shown validation of the experimental protocol on test compounds. The overall results allowed to propose a structure reactivity method in order to predict OH-oxidation rate constant of new compounds. Finally, tropospheric life times of the studied compounds were compared inside and outside a cloud.

Poulain, L.; Grubert, S.; François, S.; Monod, A.; Wortham, H.

2003-04-01

50

Methods for collection and analysis of geopressured geothermal and oil field waters  

USGS Publications Warehouse

Present methods are described for the collection, preservation, and chemical analysis of waters produced from geopressured geothermal and petroleum wells. Detailed procedures for collection include precautions and equipment necessary to ensure that the sample is representative of the water produced. Procedures for sample preservation include filtration, acidification, dilution for silica, methyl isobutyl ketone (MIBK) extraction of aluminum, addition of potassium permanganate to preserve mercury, and precipitation of carbonate species as strontium carbonate for stable carbon isotopes and total dissolved carbonate analysis. Characteristics determined at the well site are sulfide, pH, ammonia, and conductivity. Laboratory procedures are given for the analysis of lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, iron, manganese, zinc, lead, aluminum, .and mercury by atomic absorption and flame emission spectroscopy. Chloride is determined by silver nitrate titration and fluoride by ion-specific electrode. Bromide and iodide concentrations are determined by the hypochlorite oxidation method. Sulfate is analyzed by titration using barium chloride with thorin indicator after pretreatment with alumina. Boron and silica are determined colorimetrically by the carmine and molybdate-blue methods, respectively. Aliphatic acid anions (C2 through C5) are determined by gas chromatography after separation and concentration in a chloroform-butanol mixture.

Lico, Michael S.; Kharaka, Yousif K.; Carothers, William W.; Wright, Victoria A.

1982-01-01

51

Organic-inorganic hybrid resists for EUVL  

NASA Astrophysics Data System (ADS)

Herein, we describe preliminary results on organic-inorganic hybrid photoresists, capable of showing line patterns up to 16 nm under e-beam exposure studies, prepared by incorporating polyoxometalates (POMs) clusters into organic photoresist materials. Various Mo and W based clusters such as (TBA)2[Mo6O19], (TBA)5(H)[P2V3W15O62] and (TBA)4[P2Mo18O61] (where TBA = tetrabutyl ammonium counter ion) have been incorporated into PMMA matrix by mixing POM solutions and standard PMMA polymer in anisole (MW ~ 95000, MicroChem) in 1:33 w/v ratio. E-beam exposure followed by development with MIBK solutions showed that these new organic-inorganic hybrid photoresists show good line patterns upto 16 nm, which were not observed in the case of control experiments done on pure PMMA polymer resist. The observed enhancement of resist properties in the case of hybrid resists could possibly be due to a combination of features imparted to the resist by the POM clusters such as increased sensitivity, etch resistance and thermal stability.

Singh, Vikram; Kalyani, Vishwanath; Satyanarayana, V. S. V.; Pradeep, Chullikkattil P.; Ghosh, Subrata; Sharma, Satinder; Gonsalves, Kenneth E.

2014-03-01

52

Dietary exposure to cadmium, lead and nickel among students from the south-east region of Poland.  

PubMed

Dietary intake of cadmium, lead and nickel was determined among students from three universities in Lublin to assess the levels of exposure to these contaminants compared to PTWI and TDI values. The study was performed in 2006-2010 and involved 850 daily food rations of students from the south-east region of Poland. The technique of 24-hour dietary recall and diet duplicates was used. Cadmium, lead and nickel complexes with ammonium-pyrrolidindithiocarbamate were formed and extracted to the organic phase with 4-methylpentan-2-one - MIBK in which their content was measured by flame atomic absorption spectrometry. The highest intake of the elements studied was observed in 2008. The data show that in none of the cases, the level of intake reached 70 % of PTWI/TDI values and thus the risk of developing diseases related to high exposure to these toxic metals absorbed from foodstuffs was low. The parameters of methods were checked during determinations by adding standard solutions to the samples before mineralization and by using two reference materials: Total diet ARC/CL HDP and Bovine muscle RM NIST 8414. The dietary exposure to lead and cadmium has significantly decreased in recent years whereas the exposures to nickel remain on stable levels. PMID:25528928

Marzec, Zbigniew; Koch, Wojciech; Marzec, Agnieszka; ?ukiewicz-Sobczak, Wioletta

2014-11-26

53

In situ atom trapping of Bi on W-coated slotted quartz tube flame atomic absorption spectrometry and interference studies  

NASA Astrophysics Data System (ADS)

Analytical performances of metal coated slotted quartz tube flame atomic absorption spectrometry (SQT-FAAS) and slotted quartz tube in situ atom trapping flame atomic absorption spectrometry (SQT-AT-FAAS) systems were evaluated for determination of Bi. Non-volatile elements such as Mo, Zr, W and Ta were tried as coating materials. It was observed that W-coated SQT gave the best sensitivity for the determination of Bi for SQT-FAAS and SQT-AT-FAAS. The parameters for W-coated SQT-FAAS and W-coated SQT-AT-FAAS were optimized. Sensitivity of FAAS for Bi was improved as 4.0 fold by W-coated SQT-FAAS while 613 fold enhancement in sensitivity was achieved by W-coated SQT-AT-FAAS using 5.0 min trapping with respect to conventional FAAS. MIBK was selected as organic solvent for the re-atomization of Bi from the trapping surface. Limit of detection values for W-coated SQT-FAAS and W-coated SQT-AT-FAAS was obtained as 0.14 ?g mL- 1 and 0.51 ng mL- 1, respectively. Linear calibration plot was obtained in the range of 2.5-25.0 ng mL- 1 for W-coated SQT-AT-FAAS. Accuracy of the W-coated SQT-AT-FAAS system was checked by analyzing a standard reference material, NIST 1643e.

K?l?nç, Ersin; Bak?rdere, Sezgin; Ayd?n, F?rat; Ataman, O. Yavuz

2013-11-01

54

Biofiltration of a mixture of volatile organic compounds on granular activated carbon.  

PubMed

The performance of a biofilter packed with Active Carbon (AC) was evaluated. The effluent (alcohol, ketones, esters, aromatic and chlorinated compounds) treated was a representative mixture of most common industrial emissions. To achieve a better knowledge of multicomponent adsorption mechanisms, and to underline the interest of inoculating AC, a control abiotic humidified filter had been operated in the same conditions as the biofilter. For a load of 110 g VOC m(-3) AC h(-1), after 55 days of operation, the removal efficiency was higher in the biotic than in the abiotic filter (85% vs 55%, respectively). Moreover, in the biofilter, at steady state, the elimination of all compounds was almost complete except for chlorinated compounds and p-xylene (removal efficiency of 25% and 64%, respectively). The microbial colonization of AC involved a decrease of the adsorption sites accessibility and enhanced the treatment of VOCs (volatile organic compounds) having a lower affinity for activated carbon. Moreover, while aromatic compounds and MIBK were eliminated along the overall height of the biofilter, pollutants with reduced affinity for AC, such as methanol, acetone, and halogenated compounds were only treated on the second half of the reactor. Thus, the affinity for activated carbon was an important parameter controlling the biodegradation process. Nevertheless, the use of AC as packing material in biofilters treating complex mixtures of VOCs is limited. Actually, similar removal efficiency could be reached, in the same conditions, for a biofilter packed with granular peat. Furthermore, for the biofilter packed with AC, the column height necessary to remove biodegradable compounds, with reduced affinity for the support, was important. PMID:12800142

Aizpuru, A; Malhautier, L; Roux, J C; Fanlo, J L

2003-08-20

55

Mechanism of transport and distribution of organic solvents in blood  

NASA Technical Reports Server (NTRS)

Little is known about the mechanism of transport and distribution of volatile organic compounds in blood. Studies were conducted on five typical organic solvents to investigate how these compounds are transported and distributed in blood. Groups of four to five rats were exposed for 2 hr to 500 ppm of n-hexane, toluene, chloroform, methyl isobutyl ketone (MIBK), or diethyl ether vapor; 94, 66, 90, 51, or 49%, respectively, of these solvents in the blood were found in the red blood cells (RBCs). Very similar results were obtained in vitro when aqueous solutions of these solvents were added to rat blood. In vitro studies were also conducted on human blood with these solvents; 66, 43, 65, 49, or 46%, respectively, of the added solvent was taken up by the RBCs. These results indicate that RBCs from humans and rats exhibited substantial differences in affinity for the three more hydrophobic solvents studied. When solutions of these solvents were added to human plasma and RBC samples, large fractions (51-96%) of the solvents were recovered from ammonium sulfate-precipitated plasma proteins and hemoglobin. Smaller fractions were recovered from plasma water and red cell water. Less than 10% of each of the added solvents in RBC samples was found in the red cell membrane ghosts. These results indicate that RBCs play an important role in the uptake and transport of these solvents. Proteins, chiefly hemoglobin, are the major carriers of these compounds in blood. It can be inferred from the results of the present study that volatile lipophilic organic solvents are probably taken up by the hydrophobic sites of blood proteins.

Lam, C. W.; Galen, T. J.; Boyd, J. F.; Pierson, D. L.

1990-01-01

56

The Role of Residual Casting Solvent in Determining the Lithographic and Dissolution Behavior of Poly(methyl Methacrylate), a Positive Electron Beam Resist.  

NASA Astrophysics Data System (ADS)

The effect of the pre-exposure bake and the choice of casting solvent on the sensitivity and contrast of PMMA has been documented to an extent not previously reported in the literature. PMMA films were spin cast onto clean silicon substrates from chlorobenzene and tri-chloroethylene solutions. The temperature of the pre-bake was varied over the range of 59^circ to 170^circC using a convection oven with pre-bake times ranging from 30 to 90 minutes. At the end of the designated bake time, the films were removed from the oven and allowed to cool in a temperature and humidity controlled environment. They were promptly exposed to a 15 KeV electron beam, then developed, with mild agitation, in a 1:1 mixture of MIBK and IPA at 22.5^ circC. Film thickness profiles were determined with an alpha-step profilometer. Films baked at temperatures below T_{rm glass} (the temperature which marks the onset of long-range, coordinated molecular motion), exhibited improved sensitivity and poorer contrast when compared to those baked above T_{rm glass }. Unique to this work is the finding that the lithographic performance depends on the choice of casting solvent, even at pre-bake temperatures significantly above T_{rm glass}. The relative concentrations of the casting solvents remaining in the baked films was determined from UV absorption spectra. The dissolution rates of exposed films were also measured and compared to the fragmented molecular weight model of development. Energy depositions were calculated from the empirical model of Everhart and Hoff. Cross-correlation of these results indicate that the pre-bake temperature more strongly correlates with the observed improvement in sensitivity than the presence of residual casting solvent. Residual casting solvent changes the density of the film, thus changing the energy deposition and dissolution behavior. Calculations based on the aforementioned models indicate that the observed lithographic and dissolution behavior can not be accounted for by this change in density. Arguments are presented to support the conclusion that the observed behavior is associated with film morphology. Comparison of results from films cast from TCE and chlorobenzene and baked above T_{rm glass} further support this conclusion.

Criss, Robert Randolph, Jr.

57

Stabilities of 58 volatile organic compounds in fused-silica-lined and SUMMA polished canisters under various humidified conditions.  

PubMed

Fused-silica-lined (FSL) canisters and SUMMA polished (SUMMA) canisters were compared for the recoveries and the stabilities of 58 volatile organic compounds (VOCs) at low ppbv (volume/volume) levels under various humidified conditions using a three-stage preconcentration method followed by GC-MS analysis. The target VOCs included non-polar VOCs (e.g. halogenated hydrocarbons and aromatic hydrocarbons) and polar VOCs (e.g. alcohols, ketones, esters, ethers, nitriles and thiols). The three-stage preconcentration method was initially optimized for simultaneous analysis of non-polar and polar VOCs because determination of canister stability is dependent on the accuracy of analytical measurements. The method showed good linearity over the concentration range from 1 to 25 ppbv for all target analytes, and the correlation coefficients were higher than 0.9974. The method detection limits ranged from 0.023 to 0.39 ppbv. The test mixtures loaded in both type of canisters (n = 3) had concentrations of 1.7-2.5 ppbv per compound at ambient pressure under various humidified conditions (%RH = 1.6, 8.0, 27, 39, 53 and >99% with excess water present). All canister samples were initially analyzed on day 0 (after 6-12 h). The effect of competitive adsorption of water vapor and polar VOCs on active sites of interior surface was remarkably observed for SUMMA canisters. Polar VOCs had a greater requirement for water vapor to be present. The RH percentages that ensured good recovery on day 0 were RH > 8% for non-polar VOCs and RH > 27% for polar VOCs (except alcohols under the condition of RH > 99%). All thiols were not recovered from SUMMA canisters under all conditions. FSL canisters showed good recoveries of more than 86% for all VOCs under all conditions on day 0 (except alcohols under the condition of RH > 99%). The recoveries of alcohols in both canisters under the condition of RH > 99% displayed relatively low recoveries in the range 25-76% because of the partitioning effect into condensed water. The canister samples under the conditions of RH 8.0, 27, 53 and > 99% were analyzed for the stability test on days 3, 7, 14 and 28 after loading. All non-polar VOCs were reasonably stable in the FSL canisters under all examined conditions over 28 days. However, several polar VOCs that have relatively lower vapor pressure, e.g. MIBK, butyl acetate and alcohols except ethanol, showed unstable characteristics under relatively dry conditions (RH 8 and 27%) during 28 days. RH > 53% was needed to ensure good stabilities of all analytes except thiols with the recoveries of > 80% over 28 days for both canisters. Although the FSL canister showed good recoveries of more than 86% for thiols on day 0, drastic degradations were observed after day 3 and they were not detected after day 14. PMID:12509040

Ochiai, Nobuo; Tsuji, Akira; Nakamura, Naomi; Daishima, Shigeki; Cardin, Daniel B

2002-12-01