Effects of acid conditions on element distribution beneath a sulphur basepad

International Nuclear Information System (INIS)

Sevigny, J.H.; Fennell, J.W.; Sharma, A.

1997-04-01

A reconnaissance-scale study was conducted to determine the extent of acid conditions beneath a sulphur basepad at Canadian Occidental's Balzac sour gas plant and to examine the effects of acid conditions on element distribution in the subsurface. Sulphur which is extracted from sour natural gas is stored in large blocks directly on the ground. The elemental sulphur will oxidize to H 2 SO 4 under aerobic conditions and with the proper microorganisms can result in possible removal of metals from the soil and transportation in the groundwater. The basepad at the sour gas plant is 36 years old and is covered by about 1 metre of elemental sulphur. EM31 terrain conductivity and electrical resistivity tomography geophysical surveys were conducted to determine aerial and subsurface bulk electrical conductivity. The objective was to locate the indurated layer using the geophysical techniques and soil boring. The extent of acid conditions beneath the sulphur block was determined. Migration rates for the site were also estimated. Results suggested that minimal soil and groundwater impact can be expected from sulphur blocks overlying properly buffered soils, and that synthetic liners beneath sulphur blocks may not be a necessary measure at sour gas plants in Alberta. 19 refs., 6 tabs., 6 figs., 5 appendices

The use of ion-selective membranes for the recovery of sulphuric acid out of contaminated solutions. Comparing electrodialysis, electro electrodialysis and diffusion dialysis

International Nuclear Information System (INIS)

Cattoir, S.

1998-02-01

The amount of waste arising from dismantled reactors is minimized by decontamination processes. These processes result in contaminated effluents, containing acid and metal salts. The quantity of final waste can be substantially reduced when the acid is extracted out of the decontamination effluents prior to neutralisation. This report discusses three membrane techniques for the displacement of acids out of mixed acid/salt solutions: electrodialysis (ED), electro electrodialysis (EED) and diffusion dialysis (DD). EED uses an electrical potential difference across an anion-selective membrane; DD uses a concentration difference across an anion-selective membrane; ED uses an electrical potential difference, across an anion- and a cation-selective membrane. EED can displace up to 90% of the sulphuric acid, the amount of metal ions in the displaced-acid solution is less than 1% of the ions in the original contaminated solution. Treatment costs are estimated to about 18 Belgian Francs per litre. In DD the purity of the displaced acid is comparable to EED. Treatment costs are about 21 Belgian Francs per litre. In ED 90% acid-displacement is easily reached, but 5% metal ions are also displaced. Treatment costs are about 6 Belgian Francs per litre. Therefore, in spite of the lower purity of the resulting acid, ED is economically speaking the best choice

Electrochemical dissolution of tin in methanesulphonic acid solutions

NARCIS (Netherlands)

de Greef, R.A.T.; Janssen, L.J.J.

2001-01-01

High-rate electroplating of tin on a moving steel strip is generally carried out in cells with dimensionally stable anodes. To obtain a matt tin deposit a concentrated acidic tin methanesulphonate solution containing a small concentration of sulphuric acid is used. The concentrated tin

The non-participation of organic sulphur in acid mine drainage generation.

Science.gov (United States)

Casagrande, D J; Finkelman, R B; Caruccio, F T

1989-12-01

Acid mine drainage is commonly associated with land disturbances that encounter and expose iron sulphides to oxidising atmospheric conditions. The attendant acidic conditions solubilise a host of trace metals. Within this flow regime the potential exists to contaminate surface drinking water supplies with a variety of trace materials. Accordingly, in evaluating the applications for mines located in the headwaters of water sheds, the pre-mining prediction of the occurrence of acid mine drainage is of paramount importance.There is general agreement among investigators that coal organic sulphur is a nonparticipant in acid mine drainage generation; however, there is no scientific documentation to support this concensus. Using simulated weathering, kinetic, mass balance, petrographic analysis and a peroxide oxidation procedure, coal organic sulphur is shown to be a nonparticipant in acid mine drainage generation. Calculations for assessing the acid-generating potential of a sedimentary rock should not include organic sulphur content.

Sulphur highways : value-added solutions to create sulphur demand

Energy Technology Data Exchange (ETDEWEB)

Macedo, R.

2010-09-15

Producers generally view sulphur as a nuisance with essentially no benefit. In Alberta, a greater portion of sulphur production will shift from natural gas to the oilsands producing areas where there is limited infrastructure to move it out. Increased amounts of sour oil and gas production together with greater fuel desulphurization have also led to more sulphur being produced. In order to address the inevitable storage issue, Shell is considering value-added uses for the product, such as sulphur asphalt. The company developed Thiopave, a sulphur-based product for use in asphalt paving mixtures that can improve the mechanical performance of asphalt. The sulphur can be added to the asphalt mix as a solid pellet, which helps reduce the emission of sulphur vapour, odour and eye irritation. Twenty Thiopave projects are planned for the 2010 paving season in 9 U.S. states and 2 Canadian provinces. Sulphur Enhanced Asphalt Modifier (SEAM) was the first generation of Thiopave developed in 2003. SEAM replaces 20 to 25 percent by volume of the bitumen in asphalt mix. The properties allow Thiopave-enhanced roads to perform better than conventional roads in both consistently high temperature regions and climates with wide temperature variations. In 2007, an asphalt mix containing 40 percent by mass of Thiopave was used in a trial in Qatar. The Thiopave asphalt mix was compared with a conventional mix at temperatures ranging from 10 to 40 degrees C to determine the stiffness ratio. It was determined that Thiopave mixes containing high-penetration bitumen can be used to build temperature resistant roads that are stiffer in hot summer temperatures while improving the pavement's cold weather cracking performance. 1 ref., 4 figs.

Isotopic equilibria between sulphur solute species at high temperature

International Nuclear Information System (INIS)

Robinson, B.W.

1978-01-01

Sulphur solute species in ore solutions and geothermal discharges include HSO 4 - , SO 4 2- , H 2 S, and HS - , as well as the ion-paired species, NaHS 0 , NaHSO 4 - and Na 2 SO 4 0 . Observed sulphate-sulphide fractionation factors and the rates of attainment of isotopic equilibrium are likely to depend on the nature of the sulphur species actually taking part in these isotopic equilibria. Preliminary experiments in alkaline solution (pH 10.1 at 20 0 C) were carried out in a gold cell. No significant isotope fractionation was observed between the SO 4 2- and HS - in 29 days at 200 0 C, 63days at 300 0 C, or 90 days at 250 0 C. However, similar experiments at 350 0 C in sealed gold capsules at room temperature pH 8.5 showed slow exchange(t( 1 / 2 ) was calculated to be 510 days for the SO 4 2- -HS - exchange reaction using the theoretical fractionation of 20.2 0 / 00 ). The addition of NaCl appeared to have no affect on the exchange. However, pH strongly controls the reaction rate, and exchange probably involves H 2 S and the HSO 4 - ion. Additional preliminary experiments were conducted with a fivefold increase in the sulphur concentration; a decrease in t( 1 / 2 ) to 142 days resulted. Some inter-relationship between sulphur concentration and exchange rate thus exists. The important controlling parameters of isotope exchange (temperature, pH, and ΣS) can be seen to have influenced exchange in natural systems.(auth.)

Comparison of the SAWNUC model with CLOUD measurements of sulphuric acid-water nucleation.

Science.gov (United States)

Ehrhart, Sebastian; Ickes, Luisa; Almeida, Joao; Amorim, Antonio; Barmet, Peter; Bianchi, Federico; Dommen, Josef; Dunne, Eimear M; Duplissy, Jonathan; Franchin, Alessandro; Kangasluoma, Juha; Kirkby, Jasper; Kürten, Andreas; Kupc, Agnieszka; Lehtipalo, Katrianne; Nieminen, Tuomo; Riccobono, Francesco; Rondo, Linda; Schobesberger, Siegfried; Steiner, Gerhard; Tomé, António; Wimmer, Daniela; Baltensperger, Urs; Wagner, Paul E; Curtius, Joachim

2016-10-27

Binary nucleation of sulphuric acid-water particles is expected to be an important process in the free troposphere at low temperatures. SAWNUC (Sulphuric Acid Water Nucleation) is a model of binary nucleation that is based on laboratory measurements of the binding energies of sulphuric acid and water in charged and neutral clusters. Predictions of SAWNUC are compared for the first time comprehensively with experimental binary nucleation data from the CLOUD chamber at European Organization for Nuclear Research. The experimental measurements span a temperature range of 208-292 K, sulphuric acid concentrations from 1·10 6 to 1·10 9  cm -3 , and distinguish between ion-induced and neutral nucleation. Good agreement, within a factor of 5, is found between the experimental and modeled formation rates for ion-induced nucleation at 278 K and below and for neutral nucleation at 208 and 223 K. Differences at warm temperatures are attributed to ammonia contamination which was indicated by the presence of ammonia-sulphuric acid clusters, detected by an Atmospheric Pressure Interface Time of Flight (APi-TOF) mass spectrometer. APi-TOF measurements of the sulphuric acid ion cluster distributions ( (H2SO4)i·HSO4- with i = 0, 1, ..., 10) show qualitative agreement with the SAWNUC ion cluster distributions. Remaining differences between the measured and modeled distributions are most likely due to fragmentation in the APi-TOF. The CLOUD results are in good agreement with previously measured cluster binding energies and show the SAWNUC model to be a good representation of ion-induced and neutral binary nucleation of sulphuric acid-water clusters in the middle and upper troposphere.

Oxidation of inorganic compounds of sulphur by various sulphur bacteria

Energy Technology Data Exchange (ETDEWEB)

Parker, C D; Prisk, J

1953-01-01

Cultures of thiobacillus thiooxidans, Th. thioparus, Th. novellus, Thiobacillus b strains t and kand Th. concretivorus, Thiobacillus x and the m strains, organisms isolated from concrete were examined to elucidate the mode of oxidation and to establish the identity of the organisms recently isolated from corroded concrete. Thiosulphate was oxidized by all these bacteria. Th. thiooxidans, Th. concretivorus and Thiobacillus x first converted it to tetrathionate and sulphate and then oxidized the tetrathionate to sulphate and free sulphuric acid. Thiobaciullus x differed from the other two in that, owing to a lesser acid tolerance, some tetrathionate was found in the final products of oxidation. Th. Thioparus converted thiosulphate to sulphate and sulphur, followed by partial oxidation of the sulphur to sulphuric acid. Th. novellus produced sulphate and sulphuric acid. Thiobacillus b, the t and k strains and the m strains formed sulphate and tetrathionate with temporary increase in pH value; only Thiobacillus x oxidized tetrationate, yielding sulphate and sulphuric acid. Elementary sulphur was oxidized by Th. thiooxidans, th. Concretivorus, thiobacillus x and Th. thioparus; the rates of oxidation decreased in that order, and the only product was sulphuric acid. Hydrogen sulphide was oxidized only at low concentrations and only by th. Concretivorus and Thiobacillus x; sulphuric acid was the end-product, and elementary sulphur may have been an intermediate. Thiobacillus x differed from Th. thiooxidans in pH range for growth and from Th. thioparus in its method of oxidation of thiosulphate, tetrathionate and H/sub 2/S. The m strains were similar to thiobacillus b and the t and k strains of trautwein.

Determination of the O/M ratios of polynary uranium oxides by Ce(IV)-Fe(II) back titration after dissolution in mixed sulphuric and phosphoric acids.

Science.gov (United States)

Fujino, T; Sato, N; Yamada, K

1996-01-01

Uranium (IV) in polynary uranium oxides is determined after the solid has been dissolved in a warm mixed solution of sulphuric and phosphoric acids containing excess Ce(IV). The latter is titrated with a Fe(II) standard solution using ferroin as indicator. This method is especially effective for (mixed) uranium oxides which are difficult to dissolve in hot Ce(IV) sulphuric acid. The standard deviation of the determined x value in polynary oxides is estimated to be below +/- 0.004 for samples of 10-30 mg.

发烟硫酸浓度互换公式的推导%Derivation about Concentrations Exchanging Formula of Fuming Sulphuric Acid

Institute of Scientific and Technical Information of China (English)

谭靖辉; 唐淑贞

2011-01-01

指出发烟硫酸是游离态SO3的H2SO4溶液,运用质量守恒定律对发烟硫酸浓度互换公式进行了推导,阐述了使用该公式的注意事项。%Fuming sulphuric acid was regarded as SO3 of free state in sulfuric acid solution,concentrations exchanging formula of fuming sulphuric acid was deduced by mass conservation law,attentions of formula were expounded.

Comparison of methods for the determination of reduced inorganic sulphur in acid sulphate soils

International Nuclear Information System (INIS)

Santomartino, S.L.

1999-01-01

Full text: The management of acid sulphate soils requires analytical methods that provide accurate data on the quantity of reduced inorganic sulphur within a soil, as it is this fraction that produces acid upon oxidation. This study uses sulphidic Coode Island Silt samples to compare common analytical methods including POCAS (Peroxide Oxidation-Combined Acidity and Sulphate) which consists of TSA (Total Sulphidic Acidity), S pos (Peroxide Oxidisable Sulphur), TOS (Total Oxidisable Sulphur) and chromium-reducible sulphur. The determination of total sulphur by Leco sulphur is strongly correlated with, but slightly less than, that analysed by XRF. Comparison of soil sulphide content by chromium-reducible sulphur, TSA and TOS methods indicates that TOS values are substantially higher than both other methods. The problem with the TOS method lies in the sulphate extraction procedure. Hot distilled water and HCI are commonly used as extractants, however hot distilled water fails to remove organic sulphur, thereby overestimating the sulphide content of the soil. Leco carbon analyses verify that a substantial proportion of organic matter exists within the samples. The HCI extraction process, which uses Ion Chromatography to analyse for sulphate, produces highly inaccurate results due to the interference of the sulphate peak by the chloride peak during analysis. An alternative method involving HCI extraction and XRF analysis of the soil residue is currently being undertaken. The use of KCI to extract sulphate generally produces values similar to the hot distilled water method. The sulphidic content measured by TSA is strongly correlated with, but slightly higher than that determined by the chromium-reducible sulphur method. This is attributed to the use of hydrogen peroxide in the TSA method, which oxidises organic matter to organic acids in addition to oxidising sulphides. These preliminary findings indicate that the chromium-reducible sulphur method is the most suitable

Chemical dosimetry at less than 1000 rad: aqueous trimesic acid solutions

International Nuclear Information System (INIS)

Matthews, R.W.; Wilson, J.G.

1981-01-01

Aqueous solutions of trimesic acid were investigated for possible use as a chemical dosimeter. In aerated 10 -2 M sulphuric acid solution containing 10 -3 M trimesic acid, a highly fluorescent product is formed with its maximum fluorescence at 450nm when excited by 350nm light. The product has fluorescence characteristics very similar to quinine in 0.05 M sulphuric acid. The fluorescence intensity is linear with dose in the range 1-1000 rad and a precision of +-2% was obtained from a number of runs. Solutions are stable for at least several days before and after irradiation. The yield is little affected by moderate changes in trimesic acid concentration, oxygen concentration, water purity, energy of radiation and irradiation temperature. The small dependence of the yield on dose rate and the effect of measurement temperature on the fluorescence signal have been quantified. The most significant factor affecting the fluorescence signal is the hydrogen ion concentration of the solution. In aerated neutral and alkaline (pH 10) solutions, hydroxytrimesic acid (HTMA) is formed with G(HTMA) equal to 2.07 +- 0.04 and 2.21 +- 0.04, for 10 -3 M trimesate. In these solutions, G(HTMA) increases appreciably with increase in the trimesate concentration. The main fluorescent product formed in irradiated acid solutions was not identified but it was not HTMA. (author)

Optimisation of Dilute Sulphuric Acid Hydrolysis of Waste ...

African Journals Online (AJOL)

Dilute sulphuric acid hydrolysis of waste paper was investigated in this study. The effects of acid concentration, time, temperature and liquid to solid ratio on the total reducing sugar concentration were studied over three levels using a four variable Box-Behnken design (BBD). A statistical model was developed for the ...

Determination of the O/M ratios of polynary uranium oxides by Ce(IV)-Fe(II) back titration after dissolution in mixed sulphuric and phosphoric acids

International Nuclear Information System (INIS)

Fujino, T.; Sato, N.; Yamada, K.

1996-01-01

Uranium (IV) in polynary uranium oxides is determined after the solid has been dissolved in a warm mixed solution of sulphuric and phosphoric acids containing excess Ce(IV). The latter is titrated with a Fe(II) standard solution using ferroin as indicator. This method is especially effective for (mixed) uranium oxides which are difficult to dissolve in hot Ce(IV) sulphuric acid. The standard deviation of the determined x value in polynary oxides is estimated to be below ± 0.004 for samples of 10-30 mg. (orig.)

Effect of Schiff's Bases as Corrosion Inhibitors on Mild Steel in Sulphuric Acid

Directory of Open Access Journals (Sweden)

R. K. Upadhyay

2007-01-01

Full Text Available Mass loss and thermometric methods have been used to study the corrosion inhibitory effect of synthesised Schiff's bases viz. N-(furfurilidine – 4- methoxy aniline (SB1, N-(furfurilidine – 4- methylaniline (SB2, N-(salicylidine – 4- methoxy aniline (SB3, N-(cinnamalidine – 4 –methoxy aniline (SB4 and N-(cinnamalidine - 2-methylaniline (SB5 on mild steel in sulphuric acid solutions. Results show that both methods have good agreement with each other and inhibition efficiency depends upon the concentration of inhibitor as well as that of acid. Maximum inhibition efficiency is shown at highest concentration of Schiff's bases at the highest strength of acid.

Comparison of the SAWNUC model with CLOUD measurements of sulphuric acid-water nucleation

CERN Document Server

Ehrhart, Sebastian; Almeida, Joao; Amorim, Antonio; Barmet, Peter; Bianchi, Federico; Dommen, Josef; Dunne, Eimear M; Duplissy, Jonathan; Franchin, Alessandro; Kangasluoma, Juha; Kirkby, Jasper; Kürten, Andreas; Kupc, Agnieszka; Lehtipalo, Katrianne; Nieminen, Tuomo; Riccobono, Francesco; Rondo, Linda; Schobesberger, Siegfried; Steiner, Gerhard; Tomé, António; Wimmer, Daniela; Baltensperger, Urs; Wagner, Paul E; Curtius, Joachim

2016-01-01

Binary nucleation of sulphuric acid-water particles is expected to be an important process in the free troposphere at low temperatures. SAWNUC (Sulphuric Acid Water Nucleation) is a model of binary nucleation that is based on laboratory measurements of the binding energies of sulphuric acid and water in charged and neutral clusters. Predictions of SAWNUC are compared for the first time comprehensively with experimental binary nucleation data from the CLOUD chamber at European Organization for Nuclear Research. The experimental measurements span a temperature range of 208–292 K, sulphuric acid concentrations from 1·106 to 1·109 cm−3, and distinguish between ion-induced and neutral nucleation. Good agreement, within a factor of 5, is found between the experimental and modeled formation rates for ion-induced nucleation at 278 K and below and for neutral nucleation at 208 and 223 K. Differences at warm temperatures are attributed to ammonia contamination which was indicated by the presence of ammonia-sulphu...

Accidental sulphuric acid poisoning in a newborn | Abdulkadir ...

African Journals Online (AJOL)

Accidental sulphuric acid poisoning in a newborn. I Abdulkadir, L Hassan, F Abdullahi, FD Akeredolu, S Purdue, M Okpe, AM Sobowale, OA Adewumi, U Abdullahi, MA Onadiran, TT Sholadoye, S Baba, WN Ogala ...

Kinetics of bromide catalysed oxidation of dextrose by cerium (IV) in aqueous sulphuric acid solution

International Nuclear Information System (INIS)

Sharma, J.; Sah, M.P.

1994-01-01

Kinetics of bromide catalysed oxidation of dextrose by Ce IV in aqueous sulphuric acid medium show first order dependence each in dextrose and cerium(IV). The reaction rate decreases on increasing the concentration of hydrogen ion. The increase in [HSO 4 - ] or [SO 4 2- ] decreases the rate. The bromide ion shows positive catalytic effect on the reaction rate. The value of activation energy has been calculated and a suitable mechanism confirming to the kinetic data is proposed. (author). 3 refs., 3 tabs

THE SOLUBILITY OF MILAS BAUXITE ORE IN SULPHURIC ACI

Directory of Open Access Journals (Sweden)

Mustafa GULFEN

2001-06-01

Full Text Available The effects of calcination conditions,sulphuric acid concentrations and dissolvingtemperature and period as parameters to thesolubility of the bauxite ore from Gobekdagı reservesin Mugla-Milas region were investigated. The bauxitesamples were calcined in different periods at differenttemperatures. Then the solubility of the calcinedbauxite samples in sulphuric acid solution wasexamined. Dissolving activation energy (Ea wascalculated using the optimum kinetics equation andthe results obtained from the solubility studiesexamined dissolving temperatures and periods

Sulphur recovery and sulphur emissions at Alberta sour gas plants : annual report for 2005

International Nuclear Information System (INIS)

2005-01-01

The sulphur recovery of Alberta's grandfathered sour gas plants is monitored by the Alberta Energy and Utilities Board. This report provides an annual summary of industry performance for sulphur recovery at large acid gas flaring sour gas plants, and sulphur recovery at all acid gas injection sour gas plants. It follows Interim Directive (ID) 2001-3 which stipulates guidelines for sulphur recovery for the province of Alberta. It includes a list of grandfathered and non grandfathered plants in Alberta. Grandfathered sulphur recovery plants that exceed expectations have the option to file a sulphur emission performance credit report and can use the credits to meet some of their sulphur requirement in the future. Acid gas flaring plants face more stringent requirements and cannot earn credits. Several plants have degrandfathered in the past 5 years. Eleven have made upgrades, 4 have been relicensed to meet the requirements for new plants, and 4 have shut down. Forty-one grandfathered plants remain. Sulphur emissions have decreased 39 per cent for grandfathered acid gas flaring plants, and 28 per cent for grandfathered sulphur recovery plants. 10 tabs., 3 figs

Wet precipitators for sulphuric acid plants

International Nuclear Information System (INIS)

Ojanpera, R.O.

1989-01-01

Both the service requirements and design construction details have changed considerably in recent years for wet electrostatic precipitators as used for gas cleaning ahead of metallurgical sulphuric acid plants. Increased concern over acid quality has resulted in more emphasis on dust efficiencies compared to collection of acid mist. Also, higher static operating pressures have caused large structural loads on casing and internal components. In this paper these two issues are addressed in the following ways: Recognition that all dusts do not collect similarly. The mechanism by which various dusts collect affect the design of the entire wet gas cleaning system. Use of both traditional and newer materials of construction to accommodate the higher design pressures while still maintaining corrosion resistance

Enhanced high temperature thermoelectric response of sulphuric acid treated conducting polymer thin films

KAUST Repository

Sarath Kumar, S. R.; Kurra, Narendra; Alshareef, Husam N.

2015-01-01

We report the high temperature thermoelectric properties of solution processed pristine and sulphuric acid treated poly(3, 4-ethylenedioxythiophene):poly(4-styrenesulfonate) (or PEDOT:PSS) films. The acid treatment is shown to simultaneously enhance the electrical conductivity and Seebeck coefficient of the metal-like films, resulting in a five-fold increase in thermoelectric power factor (0.052 W/m. K ) at 460 K, compared to the pristine film. By using atomic force micrographs, Raman and impedance spectra and using a series heterogeneous model for electrical conductivity, we demonstrate that acid treatment results in the removal of PSS from the films, leading to the quenching of accumulated charge-induced energy barriers that prevent hopping conduction. The continuous removal of PSS with duration of acid treatment also alters the local band structure of PEDOT:PSS, resulting in simultaneous enhancement in Seebeck coefficient.

Enhanced high temperature thermoelectric response of sulphuric acid treated conducting polymer thin films

KAUST Repository

Sarath Kumar, S. R.

2015-11-24

We report the high temperature thermoelectric properties of solution processed pristine and sulphuric acid treated poly(3, 4-ethylenedioxythiophene):poly(4-styrenesulfonate) (or PEDOT:PSS) films. The acid treatment is shown to simultaneously enhance the electrical conductivity and Seebeck coefficient of the metal-like films, resulting in a five-fold increase in thermoelectric power factor (0.052 W/m. K ) at 460 K, compared to the pristine film. By using atomic force micrographs, Raman and impedance spectra and using a series heterogeneous model for electrical conductivity, we demonstrate that acid treatment results in the removal of PSS from the films, leading to the quenching of accumulated charge-induced energy barriers that prevent hopping conduction. The continuous removal of PSS with duration of acid treatment also alters the local band structure of PEDOT:PSS, resulting in simultaneous enhancement in Seebeck coefficient.

An analytical procedure for determination of sulphur species and isotopes in boreal acid sulphate soils and sediments

Directory of Open Access Journals (Sweden)

K. BACKLUND

2008-12-01

Full Text Available An analytical scheme suitable for boreal acid sulphate (AS soils and sediments was developed on the basis of existing methods. The presented procedure can be used to quantify and discriminate among acid volatile sulphide, cold chromium reducible sulphur, hot chromium reducible sulphur, elemental sulphur, sulphate sulphur, organic sulphur, total reducible sulphur and total sulphur. The sulphur fractions are recovered as either Ag2S or BaSO4 precipitates and can further be used for isotope analysis. Overlaps between sulphur species are common during speciation, and must be minimized. Some of these overlaps are caused by poor sampling and storage, inappropriate conditions during the distillation, or natural variations in the sample (e.g. Fe3+ interference and grain size. The procedural impact was determined by conducting tests on both artificial and natural samples containing one or several sulphur species. The method is applied on reduced sediment from an AS soil locality (Överpurmo and a brackish lake (Larsmo Lake in western Finland and the results, including S-isotopes, are discussed.;

Effects of cold stratification, sulphuric acid, submersion in hot and ...

African Journals Online (AJOL)

Effects of cold stratification, sulphuric acid, submersion in hot and tap water pretreatments in the greenhouse and open field conditions on germination of bladder-Senna ( Colutea armena Boiss. and Huet.) seeds.

Synergistic inhibition between o-phenanthroline and chloride ion for steel corrosion in sulphuric acid

International Nuclear Information System (INIS)

Li Xueming; Tang Libin; Li Lin; Mu Guannan; Liu Guangheng

2006-01-01

The corrosion inhibition of cold rolled steel in 0.5 M sulphuric acid in the presence of o-phenanthroline and sodium chloride (NaCl) has been investigated by using weight loss and electrochemical techniques. The experimental data suggest that the inhibition efficiency increases with increasing NaCl concentration in the presence of 0.0002 M o-phenanthroline, but decreases with increasing temperature. A synergistic effect is observed when o-phenanthroline and chloride ions are used together to prevent cold rolled steel corrosion in 0.5 M sulphuric acid. The polarization curves showed that the complex of o-phenanthroline and NaCl acts as a mixed type inhibitor. The experimental results suggested that the presence of chloride ions in the solution stabilized the adsorption of o-phenanthroline molecules on the metal surface and improved the inhibition efficiency of o-phenanthroline. The adsorption of the complex accords with the Langmuir adsorption isotherm. Some thermodynamic parameters such as adsorption heat, adsorption entropy and adsorption free energy have been calculated by employing thermodynamic equations. Kinetic parameters such as apparent activation energy and pre-exponential factor have been calculated and discussed

Cellulose sulphuric acid as a biodegradable catalyst for conversion ...

Indian Academy of Sciences (India)

This article describes simple and efficient method for the diazotization and azidation of different aromatic amines over cellulose sulphuric acid, sodium nitrite and sodium azide under mild conditions at room temperature. Various aryl amines possessing electron-withdrawing groups or electron-donating groups have been ...

In-situ Spectroscopic Studies and Modelling of Crystallization Processes of Sulphuric Acid Catalysts

DEFF Research Database (Denmark)

Oehlers, C.; Fehrmann, Rasmus; Masters, Stephen Grenville

1996-01-01

Deactivation of commercial and prototype sulphuric acid catalysts has been investigated in-situ by ESR spectroscopy. The influence of support pore structure,and the chemical composition of the catalyst and the gas phase was dicussed.A statistical lattice model was applied to describe the crystall......Deactivation of commercial and prototype sulphuric acid catalysts has been investigated in-situ by ESR spectroscopy. The influence of support pore structure,and the chemical composition of the catalyst and the gas phase was dicussed.A statistical lattice model was applied to describe...

Effects of sulphuric acid, mechanical scarification and wet heat ...

African Journals Online (AJOL)

Effects of different treatment methods on the germination of seeds of Parkia biglobosa (mimosaceae) were carried out. Prior treatment of seeds with sulphuric acid, wet heat and mechanical scarification were found to induce germination of the dormant seeds. These methods could be applied to raise seedlings of the plant for ...

Selective removal of chromium from sulphuric acid leach liquor of ilmenite ore by solvent extraction with trioctylamine

Directory of Open Access Journals (Sweden)

E.O. Olanipekun

2000-12-01

Full Text Available The selective removal of chromium, a trace impurity that degrades the whiteness of titanium(IV oxide pigments, from sulphuric acid leach liquor of ilmenite, was investigated by solvent extraction with xylene solutions of trioctylamine. Important factors of commercial significance affecting the extraction operation have been examined. More than 99% of the chromium was selectively removed in multiple batch extractions from the leach liquor and titanium losses were minimal (< 1%. The chromium content of extracted solutions was reduced to less than 1 ppm and thermal hydrolysis of these solutions yielded white titanium(IV oxide pigments that are suitable for use in the coatings pigment industry.

Studying titanium-molybdenum-zirconium alloys of increased corrosion resistance in acid solutions

International Nuclear Information System (INIS)

Tomashov, N.D.; Kazarin, V.I.; Mikheev, V.S.; Goncharenko, B.A.; Sigalovskaya, T.M.; Kalyanova, M.P.

1977-01-01

New promising Ti-Mo-Nb-Zr system alloys, possessing good workability and a high corrosion resistance in non-oxidizing solutions of acids, have been developed. The alloys may be recommended as structural materials for equipment operating in severely agressive acid media, such as hydrochloric, sulphuric and phosphoric acids. The corrosion resistance of alloys of the above system in solutions of H 2 SO 4 , HCl and H 3 PO 4 acids may be maximized by increasing the overall alloying to 42% (keeping the ratio of the alloying components Mo/Nb/Zr=4/1/1 unchanged), while retaining sufficiently good plasticity and workability

On the formation of sulphuric acid – amine clusters in varying atmospheric conditions and its influence on atmospheric new particle formation

Directory of Open Access Journals (Sweden)

I. K. Ortega

2012-10-01

Full Text Available Sulphuric acid is a key component in atmospheric new particle formation. However, sulphuric acid alone does not form stable enough clusters to initiate particle formation in atmospheric conditions. Strong bases, such as amines, have been suggested to stabilize sulphuric acid clusters and thus participate in particle formation. We modelled the formation rate of clusters with two sulphuric acid and two amine molecules (JA2B2 at varying atmospherically relevant conditions with respect to concentrations of sulphuric acid ([H2SO4], dimethylamine ([DMA] and trimethylamine ([TMA], temperature and relative humidity (RH. We also tested how the model results change if we assume that the clusters with two sulphuric acid and two amine molecules would act as seeds for heterogeneous nucleation of organic vapours (other than amines with higher atmospheric concentrations than sulphuric acid. The modelled formation rates JA2B2 were functions of sulphuric acid concentration with close to quadratic dependence, which is in good agreement with atmospheric observations of the connection between the particle formation rate and sulphuric acid concentration. The coefficients KA2B2 connecting the cluster formation rate and sulphuric acid concentrations as JA2B2=KA2B2[H2SO4]2 turned out to depend also on amine concentrations, temperature and relative humidity. We compared the modelled coefficients KA2B2 with the corresponding coefficients calculated from the atmospheric observations (Kobs from environments with varying temperatures and levels of anthropogenic influence. By taking into account the modelled behaviour of JA2B2 as a function of [H2SO4], temperature and RH, the atmospheric particle formation rate was reproduced more closely than with the traditional semi-empirical formulae based on sulphuric acid concentration only. The formation rates of clusters with two sulphuric acid and two amine molecules with different amine compositions (DMA or TMA or one of both had

Enhanced corrosion resistance of stainless steel type 316 in sulphuric acid solution using eco-friendly waste product

Science.gov (United States)

Sanni, O.; Popoola, A. P. I.; Fayomi, O. S. I.

2018-06-01

Literature has shown that different organic compounds are effective corrosion inhibitors for metal in acidic environments. Such compounds usually contain oxygen, nitrogen or sulphur and function through adsorption on the metal surface, thereby creating a barrier for corrosion attack. Unfortunately, these organic compounds are toxic, scarce and expensive. Therefore, plants, natural product and natural oils have been posed as cheap, environmentally acceptable, abundant, readily available and effective molecules having low environmental impact. The corrosion resistance of austenitic stainless steel Type 316 in the presence of eco-friendly waste product was studied using weight loss and potentiodynamic polarization techniques in 0.5 M H2SO4. The corrosion rate and corrosion potential of the steel was significantly altered by the studied inhibitor. Results show that increase in concentration of the inhibitor hinders the formation of the passive film. Experimental observation shows that its pitting potential depends on the concentration of the inhibitor in the acid solution due to adsorption of anions at the metal film interface. The presence of egg shell powder had a strong influence on the corrosion resistance of stainless steel Type 316 with highest inhibition efficiency of 94.74% from weight loss analysis, this is as a result of electrochemical action and inhibition of the steel by the ionized molecules of the inhibiting compound which influenced the mechanism of the redox reactions responsible for corrosion and surface deterioration. Inhibitor adsorption fits the Langmuir isotherm model. The two methods employed for the corrosion assessment were in good agreement.

Intensification of zinc dissolution process in sulphuric acid

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Stanojević D.

2005-01-01

Full Text Available Many high purity salts are produced by dissolving pure metal in non-oxidizing mineral acids. If hydrogen overpotential on the given metal is high, then the rate of overall process is defined by reaction of hydrogen ion reduction. This study investigated the possibility of accelerated dissolving of metal zinc in sulphuric acid by introducing copper cathode on which evolving hydrogen is much easier than on zinc. It was found out that the acceleration of zinc dissolving is possible and, at constant surface of copper cathode depends on the quality of electrical contact between copper electrode and zinc.

Growth of Sulphuric Acid Nanoparticles Under Wet and Dry Conditions

Czech Academy of Sciences Publication Activity Database

Škrabalová, Lenka; Brus, David; Antilla, T.; Ždímal, Vladimír; Lihavainen, H.

2014-01-01

Roč. 14, č. 12 (2014), s. 6461-6475 ISSN 1680-7316 R&D Projects: GA AV ČR IAA200760905 Grant - others:AFCEP(FI) 1118615 Institutional support: RVO:67985858 Keywords : binary nucleation * sulphuric acid - water * condensational growth Subject RIV: BJ - Thermodynamics Impact factor: 5.053, year: 2014

Adsorption of sulphuric acid on smectite from acidic aqueous solutions Adsorção de ácido sulfúrico em esmectita de soluções aquosas ácidas

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E. L. Tavani

1999-05-01

Full Text Available The adsorption of sulphuric acid on smectite from acidic aqueous solutions was studied. The amounts of cations dissolved in each equilibrium solution were determined by chemical analysis. Simultaneously, the original smectite and the smectite after each test were characterized by infrared, X-ray diffraction and swelling index. The results obtained permitted us to determine that the substitutions of the exchange cations and the chemical attack occurred at very different acid concentrations and treatment times. It was established that during the acid treatment of the smectite, a progressive damage of its crystalline structure was produced. Finally, the influences of the substitution of exchange cations and of the chemical attack in the swelling index were determined.A adsorção de ácido sulfúrico em esmectita de soluções aquosas ácidas é estudada. As concentrações de cátions dissolvidos em cada solução em equilíbrio foram determinadas por análise química. As esmectitas original e após cada teste foram simultaneamente caracterizadas por infravermelho, difração de raios X e índice de crescimento. Os resultados obtidos permitiram determinar que as substituições dos cátions de troca e o ataque químico ocorreram em diferentes concentrações de ácido e tempos de tratamento. Foi verificado que durante o tratamento em ácido da esmectita foi produzido um dano progressivo da sua estrutura cristalina. Finalmente foram determinadas as influências da substituição dos cátions de troca e do ataque químico no índice de crescimento.

Anionic Surfactant as a Corrosion Inhibitor for Synthesized Ferrous Alloy in Acidic Solution

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Farida Kellou-Kerkouche

2013-01-01

Full Text Available The effect of temperature on the corrosion behaviour of a synthesized iron-based alloy in 1 N sulphuric acid solution has been examined by means of three electrochemical techniques. Thereafter, we studied the influence of an anionic surfactant (sodium dodecyl benzene sulfonate at various concentrations on the electrochemical behaviour of the ferrous alloy. The obtained results show that the temperature increase reduced the performance of the used alloy, in the acidic environment. Otherwise, the surfactant inhibits the alloy dissolution in the sulphuric acid, through its adsorption on the metal surface without modifying the mechanism of corrosion process. We also noticed that the highest inhibition effect is obtained at a concentration above its critical micelle concentration (CMC. Langmuir adsorption isotherm fits well with the experimental data.

Quantification of sulphur amino acids by ultra-high performance liquid chromatography in aquatic invertebrates.

Science.gov (United States)

Thera, Jennifer C; Kidd, Karen A; Dodge-Lynch, M Elaine; Bertolo, Robert F

2017-12-15

We examined the performance of an ultra-high performance liquid chromatography method to quantify protein-bound sulphur amino acids in zooplankton. Both cysteic acid and methionine sulfone were linear from 5 to 250 pmol (r 2  = 0.99), with a method detection limit of 13 pmol and 9 pmol, respectively. Although there was no matrix effect on linearity, adjacent peaks and co-eluting noise from the invertebrate proteins increased the detection limits when compared to common standards. Overall, performance characteristics were reproducible and accurate, and provide a means for quantifying sulphur amino acids in aquatic invertebrates, an understudied group. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of structural and textural grain characteristics on leaching of sulphide minerals from a polymetallic concentrate by sodium nitrate and sulphuric acid solution

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Sokić Miroslav D.

2017-01-01

Full Text Available In this paper, the influence of structural and textural characteristics of sulfide minerals on their leaching from a polymetallic concentrate by sulfuric acid and sodium nitrate solution is presented. The starting material was Pb–Zn–Cu sulphide polymetallic concentrate enriched during the flotation of a polymetallic ore in the "Rudnik" flotation plant (Rudnik – Serbia. Leaching experiments were carried out in a closed glass reactor, which provides stable hermetic conditions and allows heating at constant temperature. Chemical, XRD, qualitative and quantitative microscopic and SEM/EDX analyses were used to characterizes samples of the polymetallic concentrate and leach residue. It was determined that chalcopyrite, sphalerite, galena, pyrrhotite and quartz were present in the polymetallic concentrate. The content of sulphide minerals was 69.5%, of which 60.9% occurred as liberated grains: 88.3% of chalcopyrite, 59.3% of sphalerite, 25.1% of galena and 51.6% of pirrhotite. The rest of chalcopyrite, sphalerite, galena and pirrhotite grains were in the forms of inclusions, impregnations, and simple and complex intergrowths. During the leaching process by sodium nitrate and sulphuric acid solution, it was shown previously that the leaching rate of sulphide minerals decreased with time while a part of the sulphide minerals remained in the leach residue. After leaching at 80°C for 120 min, the yields were 69.8, 82.7 and 67.1% for Cu, Zn and Fe, respectively. Lead, in the form of insoluble anglesite, remained in the leach residue. In addition to the anglesite, unleached sulfide minerals and quartz, elemental sulfur was found in the solid residue. The content of sulphide minerals was 35% of which 33.7% minerals occur independently. In specific, 54.7% of chalcopyrite, 31.9% of sphalerite, 8.2% of galena and 37.6% of pyrrhotite appear as separate grains with highly corroded surfaces. Therefore, the structural assembly of sulphide grains in the

Hydrothermal Alteration in an Acid-Sulphate Geothermal Field: Sulphur Springs, Saint Lucia

Science.gov (United States)

Joseph, E. P.; Barrett, T. J.

2017-12-01

Sulphur Springs is a vigorous geothermal field associated with the Soufrière Volcanic Centre in southern Saint Lucia. Bubbling hydrothermal pools are rich in sodium-calcium sulphate, with pHs of 3-7 and temperatures of 41-97ºC. Fumaroles have temperatures up to, and at times above, 100°C. Gases from bubbling pools and fumaroles have high contents of CO2 (601-993 mmol/mol) and H2S (3-190 mmol/mol). To investigate the nature and extent of hydrothermal alteration, detailed chemical analysis was carried out on 25 altered rocks, 10 sediments from pools and creeks in the main discharge area, and 15 little-altered rocks up to 2 km away from geothermal field. Eight altered samples were also analysed for stable isotope compositions, with mineralogy determined by X-ray diffraction and mineral liberation analysis. Least-altered host rocks comprise calc-alkaline feldspar-quartz-porphyritic dacites of near-uniform composition that form massive domes and volcaniclastic units. These rocks were emplaced 10-30 Ka ago (Lindsay et al. 2013). Within the geothermal field, the dacites have been highly altered to kaolinite, quartz, cristobalite, alunite, natroalunite, smectite, native sulphur, jarosite, gypsum and amorphous compounds. Muds from grey to blackish hydrothermal pools additionally contain iron sulphides, mainly pyrite. Despite intense alteration of the original dacites, Zr and Ti have remained essentially immobile, allowing the calculation of mass changes. Major depletions of Fe, Mg, Ca, Na and commonly Si occur over an area of at least 200 x 400 m. The most altered rocks also show losses of Al, light REE and Y, implying leaching by highly acidic waters. A few altered rocks have, however, gained Al together with Si and P. Also present are m-scale zones of silica + native sulphur, wherein the silica appears to represent a residue from the leaching of dacite, rather than a hydrothermal addition. Delta-34S values of samples containing mixtures of sulphates, native sulphur and

Sulphurous mineral waters

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Iluta Alexandru

2011-09-01

Full Text Available Sulphurous waters contain at least 1mg H2S, HS, S or thiosulphate per liter or complex colloidal sulfur water is presented as of simple or mixed sulphide (alkali, carbonated, chlorinated sodium.In the sulphurous waters, sulfur is found in several forms (hydrogen sulfide, free sulfide, sulfide groups, polysulfides acids. Yellow, opalescent white precipitate and deposit a glass of water on the bottom of sulphur oxidation by indicates the intensity of the wateroxidation process by oxygen in the air.

Effects of sulphuric acid and hot water treatments on seed ...

African Journals Online (AJOL)

A study was carried out to investigate the effects of sulphuric acid and hot water treatments on the germination of Tamarind (Tamarindus indica L). Seeds were placed on moistened filter papers in 28 cm diameter Petri dishes under laboratory condition for germination. 330 seeds of T. indica (10 seeds per Petri dish) with ...

Interactions of meteoric smoke particles with sulphuric acid in the Earth's stratosphere

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R. W. Saunders

2012-05-01

Full Text Available Nano-sized meteoric smoke particles (MSPs with iron-magnesium silicate compositions, formed in the upper mesosphere as a result of meteoric ablation, may remove sulphuric acid from the gas-phase above 40 km and may also affect the composition and behaviour of supercooled H₂SO₄-H₂O droplets in the global stratospheric aerosol (Junge layer.

This study describes a time-resolved spectroscopic analysis of the evolution of the ferric (Fe³⁺ ion originating from amorphous ferrous (Fe²⁺-based silicate powders dissolved in varying Wt % sulphuric acid (30–75 % solutions over a temperature range of 223–295 K. Complete dissolution of the particles was observed under all conditions. The first-order rate coefficient for dissolution decreases at higher Wt % and lower temperature, which is consistent with the increased solution viscosity limiting diffusion of H₂SO₄ to the particle surfaces. Dissolution under stratospheric conditions should take less than a week, and is much faster than the dissolution of crystalline Fe²⁺ compounds.

The chemistry climate model UMSLIMCAT (based on the UKMO Unified Model was then used to study the transport of MSPs through the middle atmosphere. A series of model experiments were performed with different uptake coefficients. Setting the concentration of 1.5 nm radius MSPs at 80 km to 3000 cm⁻³ (based on rocket-borne charged particle measurements, the model matches the reported Wt % Fe values of 0.5–1.0 in Junge layer sulphate particles, and the MSP optical extinction between 40 and 75 km measured by a satellite-borne spectrometer, if the global meteoric input rate is about 20 tonnes per day. The model indicates that an uptake coefficient ≥0.01 is required to account for the observed two orders of magnitude depletion of H₂SO₄ vapour above 40 km.

Isotope exchange reaction in uranous-uranyl-sulphuric acid system

International Nuclear Information System (INIS)

Ling Daren; Yue Tingsheng; Mu Dehai; Wang Yani

1990-01-01

The kinetics of the isotope exchange reaction between U(IV) and U(VI) has been studied in low concentrations of sulphuric acid. A minimum exchange rate appears at 0.25 M H 2 SO 4 . From the rates at different temperatures ranging from 20deg to 35deg C, an apparent activation energy of 86 kcal/mole was calculated. The exchange rate was found to be accelerated by the addition of ferrous ions, and a half-life of less than 1 s, was obtained. Probable mechanisms for the acceleration of the uranium isotope exchange reactions by acidity and ferrous ions are proposed. (orig.)

Studies on Corrosion of Annealed and Aged 18 Ni 250 Grade Maraging Steel in Sulphuric Acid Medium

OpenAIRE

Poornima, T.; Jagannatha, Nayak; Shetty, A. Nityananda

2010-01-01

The corrosion behavior of aged and annealed sample of 18 Ni 250 grade maraging steel was investigated in varied conditions of concentration and temperature of sulphuric acid medium, using electrochemical techniques like Tafel polarization and electrochemical impedance spectroscopy (EIS). The results obtained from both the techniques are in good agreement. These results have shown increase in corrosion rate of aged specimen with increase in concentration and temperature of sulphuric acid. With...

Quantitative Aspects of Sulphur Metabolism in the Ruminant

Energy Technology Data Exchange (ETDEWEB)

Landis, J. [Institut fuer Tierernaehrung, Eidgenoessische Technische Hochschule, Zurich (Switzerland)

1968-07-01

In a series of four experiments {sup 35}S sulphate was given intra-ruminally to lactating dairy goats at feeding times (twice daily) during periods of 10 to 11 d. Rumen contents were sampled on the 8th, 9th and 10th day of {sup 35}S application. Radioactivity was determined in the volatile sulphur fraction (sulphide-sulphur) and in protein-bound sulphur (fraction insoluble in trichloroacetic acid). The ratio between the specific activities of protein sulphur and of sulphide sulphur was considered to be an estimate for that fraction of sulphur-containing amino acids present in the proteins of rumen contents, which was synthesized by microorganisms. This interpretation is based on the assumption that sulphide is the most important source of inorganic sulphur for the synthesis of sulphur amino acids and that incorporation of inorganic sulphur compounds of a a higher state of oxidation into organic molecules may quantitatively be neglected. In three experiments the animals received rations containing 16% to 17% crude protein. In these experiments the ratio of specific activities of protein and sulphide sulphur was found to vary from 0.32 to 0.41. According to the assumptions mentioned above, this would indicate that 32 to 41% of the total amount of protein-bound sulphur amino acids were synthesized by microorganisms from inorganic (sulphide) sulphur. In the fourth experiment the animal received a ration containing only 10% protein but supplemented with urea to bring the total crude protein content to 13%. In this experiment the ratio of specific activities was 0.70, indicating a much higher contribution of microbial synthesis of sulphur amino acids than in the experiments with a more abundant protein supply. The time course of the specific activity of protein-bound-sulphur in the milk is taken as a reference base for an interpretation of labelling of body proteins in terms of turnover rates.

Ethanol and biogas production after steam pretreatment of corn stover with or without the addition of sulphuric acid

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Bondesson Pia-Maria

2013-01-01

Full Text Available Abstract Background Lignocellulosic biomass, such as corn stover, is a potential raw material for ethanol production. One step in the process of producing ethanol from lignocellulose is enzymatic hydrolysis, which produces fermentable sugars from carbohydrates present in the corn stover in the form of cellulose and hemicellulose. A pretreatment step is crucial to achieve efficient conversion of lignocellulosic biomass to soluble sugars, and later ethanol. This study has investigated steam pretreatment of corn stover, with and without sulphuric acid as catalyst, and examined the effect of residence time (5–10 min and temperature (190–210°C on glucose and xylose recovery. The pretreatment conditions with and without dilute acid that gave the highest glucose yield were then used in subsequent experiments. Materials pretreated at the optimal conditions were subjected to simultaneous saccharification and fermentation (SSF to produce ethanol, and remaining organic compounds were used to produce biogas by anaerobic digestion (AD. Results The highest glucose yield achieved was 86%, obtained after pretreatment at 210°C for 10 minutes in the absence of catalyst, followed by enzymatic hydrolysis. The highest yield using sulphuric acid, 78%, was achieved using pretreatment at 200°C for 10 minutes. These two pretreatment conditions were investigated using two different process configurations. The highest ethanol and methane yields were obtained from the material pretreated in the presence of sulphuric acid. The slurry in this case was split into a solid fraction and a liquid fraction, where the solid fraction was used to produce ethanol and the liquid fraction to produce biogas. The total energy recovery in this case was 86% of the enthalpy of combustion energy in corn stover. Conclusions The highest yield, comprising ethanol, methane and solids, was achieved using pretreatment in the presence of sulphuric acid followed by a process configuration in

Solid state radiolysis of sulphur-containing amino acids. Cysteine, cystine and methionine

International Nuclear Information System (INIS)

Franco Cataldo; Pietro Ragni; Susana Iglesias-Groth; Arturo Manchado

2011-01-01

The sulphur-containing proteinaceous amino acids l-cysteine, l-cystine and l-methionine were irradiated in the solid state to a dose of 3.2 MGy. This dose corresponds to that delivered by radionuclide decay in a timescale of 1.05 x 10 9 years to the organic matter buried at a depth >20 m in comets and asteroids. The purity of the sulphur-containing amino acids was studied by differential scanning calorimetry (DSC) before and after the solid state radiolysis and the preservation of the chirality after the radiolysis was studied by chirooptical methods (optical rotatory dispersion, ORD) and by FT-IR spectroscopy. Although the high radiation dose of 3.2 MGy delivered, all the amino acids studied show a high radiation resistance. The best radiation resistance was offered by l-cysteine. The radiolysis of l-cysteine leads to the formation of l-cystine. The radiation resistance of l-methionine is not at the level of l-cysteine but also l-methionine is able to survive the dose of 3.2 MGy. Furthermore in all cases examined the preservation of chirality after radiolysis was clearly observed by the ORD spectroscopy although a certain level of radioracemization was measured in all cases. The radioracemization is minimal in the case of l-cysteine and is more pronounced in the case of l-methionine. In conclusion, the study shows that the sulphur-containing amino acids can survive for 1.05 x 10 9 years and, after extrapolation of the data, even to the age of the Solar System i.e. to 4.6 x 10 9 years. (author)

Silica Sulphuric Acid as an Efficient Catalyst for the Catalytic and ...

African Journals Online (AJOL)

NJD

presence of a catalytic amount of silica sulphuric acid under micellar media in moderate to good yields. KEYWORDS. Sodium ... Production of aromatic nitro compounds is an important industrial process and involves the unsolved problems of ... V7 and Re9) and titanium and chromium silicates.10 Some of the procedures ...

Total mineral material, acidity, sulphur, and nitrogen in rain and snow at Kentville, Nova Scotia

Energy Technology Data Exchange (ETDEWEB)

Herman, F A; Gorham, E

1957-01-01

Analyses of total ash, sulphur, ph, ammonia, and nitrate nitrogen have been made on 23 monthly precipitation samples and 17 individual snow samples collected between June 1952 and May 1954 at Kentville, Nova Scotia, in a predominantly agricultural area. Mean annual supply of total mineral ash was 95 kg/ha, of sulphur 9.1 hg/ha, of ammonia nitrogen 2.8 kg/ha, and of nitrate nitrogen 1.1 kg/ha. Average pH was 5.7, and rains more acid than this exhibited higher levels of both nitrate and sulphur, and a marked correlation between the latter and ammonia. Snow samples had much lower concentrations of ash, sulphur, and nitrogen than rain samples collected in the same months, which may perhaps indicate a lower efficiency of snow flakes in removing materials from the atmosphere.

Probing into the effects of a magnetic field on the electrode processes of iron in sulphuric acid solutions with dichromate based on the fundamental electrochemistry kinetics

International Nuclear Information System (INIS)

Lu Zhanpeng; Huang Delun; Yang Wu

2005-01-01

The effects of an applied magnetic field on the electrode processes of iron in sulphuric acid solutions with dichromate have been investigated by electrochemical measurements. Open circuit potentials, cathodic and anodic polarisation curves, values of polarisation resistance were measured in the presence or absence of a 0.4 T horizontal magnetic field (HMF). A potentiostatic polarisation plus magnetic field perturbation technique was used to study the effect of the magnetic field on open circuit corrosion. Cathodic reaction rates at open circuit potentials for iron in sulphuric acid solutions containing dichromate ions are controlled by both the electron-transfer process and the diffusion process. A magnetic field made the open circuit potential move in the positive direction, and changes of the open circuit potentials due to the magnetic field increase with increasing dichromate concentration. When iron was potentiostatically polarised at open circuit potentials in the absence of a magnetic field, a cathodic current was observed after a magnetic field was imposed. Such cathodic currents induced by the magnetic field increases with increasing dichromate concentration. The positive shifts of open circuit potential, the decrease of polarisation resistance, and the occurrence of cathodic currents induced by the magnetic field are caused by the accelerating effect of magnetic field on the cathodic diffusion process. Measured current densities showed lower, equal, or higher values in the presence of the magnetic field than those in the absence of a magnetic field at certain anodic potentials. This effect of the magnetic field is related to the contribution of the cathodic and anodic reactions to the measured current and the types of rate-determining steps for each reaction at certain potentials. The applied magnetic field significantly decreased the polarisation resistance. The experimental results in this paper are formulated based on the fundamental electrochemistry

Procedure for recovery from an uranium containing concentrate and phosphoric acid, as well as an uranium containing concentrate and phosphoric acid obtained by this procedure

International Nuclear Information System (INIS)

1980-01-01

The phosphate ore is dissolved in sulphuric acid and the formed calcium sulphate is separated from the solution. The uranium is then precipitated by adding ammonium fluoride solution to the remaining phosphoric acid solution. When the phosphate ore is dissolved in sulphuric acid, fluorine gas is liberated and this is then used to produce the ammonium fluoride solution. (Th.P.)

The extraction of trace amounts of tantalum(V) from different mineral acid solutions by 4-(5-nonyl) pyridine oxide and trioctylamine oxide

International Nuclear Information System (INIS)

Ejaz, M.; Carswell, D.J.

1976-01-01

Data are presented on the distribution of trace amounts of tantalum(V) between different mineral acid solutions and 0.1M solutions of N-oxides of 4-(5-nonyl) pyridine and trioctylamine. The optimal acidity is 0.01-0.5M, depending on the nature of the acid. Common anions have little effect on extraction. Possible mechanism of extraction are suggested making use of slope analysis data. Separation factors for a number of metal ions with respect to tantalum are reported for the 0.1M 4-(5-nonyl)pyridine oxide - 1M sulphuric acid extraction system. Separation from uranium(VI), thorium(IV) and a number of fission products is suggested. The conclusions are unique as follows: Amine oxides are as unique as oxygen-donor extractants in their extraction of tantalum(V) from weakly acid solutions; tantalum is almost completely extracted from weakly nitric, hydrochloric and sulphuric acid solutions by both of the amine oxides; the extraction in low acidity solutions is independent of the nature of the anion of the acids present, indicating the ability of amine oxides to extract the product of hydrolysis of hydrolysable elements. In this respect amine oxides are much better than tributyl phosphate. (T.G.)

Some studies on the extraction of plutonium from phosphate containing nitric acid solutions using DBDECMP as extractant (Preprint No. CT-24)

International Nuclear Information System (INIS)

Sagar, V.B.; Pawar, S.M.; Oak, M.S.; Sivaramakrishnan, C.K.

1988-02-01

Extraction studies have been carried out to explore the feasibility of separation of Pu(IV) from phosphate containing analytical wastes generated in the laboratory. Distribution data on the extraction of Pu(IV) from dibutyl-N,N diethylcarbamoylmethylenephosphonate (DBDECMP) in xylene from an aqu eous nitric acid and its mixture with sulphuric as well as with sulphuric and phosphoric acids were obtained. Based on the data obtained the conditions for the recovery of plutonium from such waste solutions are suggested. (author)

SULPHUR-CONTAINING AMINO ACIDS METABOLISM IN EXPERIMENTAL HYPER- AND HYPOTHYROIDISM IN RATS.

Science.gov (United States)

Nechiporuk, V; Zaichko, N; Korda, М; Melnyk, A; Koloshko, O

2017-10-01

Hyper- and hypothyroidism are some of the most common endocrinopathies that cause many metabolic disorders including amino acids metabolism. However, a specific molecular mechanism of thyroid hormones influence on sulphur-containing amino acids metabolism has not been established. The aim of our research was to investigate experimentally the influence of thyroid gland functional state on the main enzymatic systems of sulphur-containing amino acids metabolism in liver and kidneys, the content of homocysteine, cysteine and H2S in blood. The rats were administered with L-thyroxine and mercazolil to simulate the states of hyper- and hypothyroidism, which were confirmed by the content of fT3, fT4 and TSH in the blood. In liver and kidneys of the animals with hypothyroidism we observed the decrease in the activity of enzymes of remethylation cycle of S-adenosylmethioninsyntase, S-adenosylhomocysteinhyhdrolase, betaine-homocysteine methyltransferase. Suppression of transsulfuration transformation of homocysteine to cysteine in hypothyroidism was mainly due to the inhibition of cystathionine synthase activity of cystathionine-β-synthase, wherein cystathionase activity of cystathionine-γ-lyase was not changed. In animals with hypothyroidism we also noticed the inhibition of cysteine desulfunation reactions: the activity of enzymes of cystathionine-β-synthase, cystathionine-γ-lyase and cysteine aminotransferase significantly decreased in liver and kidneys. Experimental hyperthyroidism was accompanied by increase in activity of remethylation cycle enzymes, increase in cystationine synthase activity of cystathionine-β-synthase in liver and activity of these enzymes in kidneys. The simulation of hyperthyroidism led to the decrease of homocysteine concentration, and of hypothyroidism - to the increase of homocysteine and cysteine concentrations and reduced H2S content in blood of the animals. Thus, the significant risk factors for the development of atherosclerosis

Molecular understanding of sulphuric acid-amine particle nucleation in the atmosphere.

Science.gov (United States)

Almeida, João; Schobesberger, Siegfried; Kürten, Andreas; Ortega, Ismael K; Kupiainen-Määttä, Oona; Praplan, Arnaud P; Adamov, Alexey; Amorim, Antonio; Bianchi, Federico; Breitenlechner, Martin; David, André; Dommen, Josef; Donahue, Neil M; Downard, Andrew; Dunne, Eimear; Duplissy, Jonathan; Ehrhart, Sebastian; Flagan, Richard C; Franchin, Alessandro; Guida, Roberto; Hakala, Jani; Hansel, Armin; Heinritzi, Martin; Henschel, Henning; Jokinen, Tuija; Junninen, Heikki; Kajos, Maija; Kangasluoma, Juha; Keskinen, Helmi; Kupc, Agnieszka; Kurtén, Theo; Kvashin, Alexander N; Laaksonen, Ari; Lehtipalo, Katrianne; Leiminger, Markus; Leppä, Johannes; Loukonen, Ville; Makhmutov, Vladimir; Mathot, Serge; McGrath, Matthew J; Nieminen, Tuomo; Olenius, Tinja; Onnela, Antti; Petäjä, Tuukka; Riccobono, Francesco; Riipinen, Ilona; Rissanen, Matti; Rondo, Linda; Ruuskanen, Taina; Santos, Filipe D; Sarnela, Nina; Schallhart, Simon; Schnitzhofer, Ralf; Seinfeld, John H; Simon, Mario; Sipilä, Mikko; Stozhkov, Yuri; Stratmann, Frank; Tomé, Antonio; Tröstl, Jasmin; Tsagkogeorgas, Georgios; Vaattovaara, Petri; Viisanen, Yrjo; Virtanen, Annele; Vrtala, Aron; Wagner, Paul E; Weingartner, Ernest; Wex, Heike; Williamson, Christina; Wimmer, Daniela; Ye, Penglin; Yli-Juuti, Taina; Carslaw, Kenneth S; Kulmala, Markku; Curtius, Joachim; Baltensperger, Urs; Worsnop, Douglas R; Vehkamäki, Hanna; Kirkby, Jasper

2013-10-17

Nucleation of aerosol particles from trace atmospheric vapours is thought to provide up to half of global cloud condensation nuclei. Aerosols can cause a net cooling of climate by scattering sunlight and by leading to smaller but more numerous cloud droplets, which makes clouds brighter and extends their lifetimes. Atmospheric aerosols derived from human activities are thought to have compensated for a large fraction of the warming caused by greenhouse gases. However, despite its importance for climate, atmospheric nucleation is poorly understood. Recently, it has been shown that sulphuric acid and ammonia cannot explain particle formation rates observed in the lower atmosphere. It is thought that amines may enhance nucleation, but until now there has been no direct evidence for amine ternary nucleation under atmospheric conditions. Here we use the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber at CERN and find that dimethylamine above three parts per trillion by volume can enhance particle formation rates more than 1,000-fold compared with ammonia, sufficient to account for the particle formation rates observed in the atmosphere. Molecular analysis of the clusters reveals that the faster nucleation is explained by a base-stabilization mechanism involving acid-amine pairs, which strongly decrease evaporation. The ion-induced contribution is generally small, reflecting the high stability of sulphuric acid-dimethylamine clusters and indicating that galactic cosmic rays exert only a small influence on their formation, except at low overall formation rates. Our experimental measurements are well reproduced by a dynamical model based on quantum chemical calculations of binding energies of molecular clusters, without any fitted parameters. These results show that, in regions of the atmosphere near amine sources, both amines and sulphur dioxide should be considered when assessing the impact of anthropogenic activities on particle formation.

An approach for degradation of grape seed and skin proanthocyanidin polymers into oligomers by sulphurous acid.

Science.gov (United States)

Luo, Lanxin; Cui, Yan; Cheng, Jinhui; Fang, Bairui; Wei, Zongmin; Sun, Baoshan

2018-08-01

To develop an efficient method for degradation of grape seed and skin proanthocyanidins polymers into oligomers, an optimized sulphurous acid degradation conditions for grape seed with the temperature of 60 °C, reaction time of 60 min and sample-sulphurous acid ratio of 1:0.2, and for grape skin with the temperature of 40 °C, reaction time of 60 min and sample-sulphurous acid ratio of 1:0.2, were established. Afterwards, HSCCC and prep-HPLC were used to fractionate and isolate individual proanthocyanidin oligomers from the degradation products. Total of ten dimeric or trimeric procyanidins were obtained, and most of them presented high yield (from 0.7 mg to 13.6 mg per run in grape seed and from 0.5 mg to 4.1 mg per run in grape skin) and high purity (over 90%). The proposed method provides a new way for large preparation of oligomeric proanthocyanidins from naturally abundant and wasted polymeric ones. Copyright © 2018 Elsevier Ltd. All rights reserved.

Recovery of uranium from analytical waste solution

International Nuclear Information System (INIS)

Kumar, Pradeep; Anitha, M.; Singh, D.K.

2016-01-01

Dispersion fuels are considered as advance fuel for the nuclear reactor. Liquid waste containing significant quantity of uranium gets generated during chemical characterization of dispersion fuel. The present paper highlights the effort in devising a counter current solvent extraction process based on the synergistic mixture of D2EHPA and Cyanex 923 to recover uranium from such waste solutions. A typical analytical waste solution was found to have the following composition: U 3 O 8 (∼3 g/L), Al: 0.3 g/L, V: 15 ppm, Phosphoric acid: 3M, sulphuric acid : 1M and nitric acid : 1M. The aqueous solution is composed of mixture of either 3M phosphoric acid and 1M sulphuric acid or 1M sulphuric acid and 1M nitric acid, keeping metallic concentrations in the above mentioned range. Different organic solvents were tested. Based on the higher extraction of uranium with synergistic mixture of 0.5M D2EHPA + 0.125M Cyanex 923, it was selected for further investigation in the present work

Impact of sulphur fumigation on the chemistry of ginger.

Science.gov (United States)

Wu, Cheng-Ying; Kong, Ming; Zhang, Wei; Long, Fang; Zhou, Jing; Zhou, Shan-Shan; Xu, Jin-Di; Xu, Jun; Li, Song-Lin

2018-01-15

Ginger (Zingiberis Rhizoma), a commonly-consumed food supplement, is often sulphur-fumigated during post-harvest handling, but it remains unknown if sulphur fumigation induces chemical transformations in ginger. In this study, the effects of sulphur fumigation on ginger chemicals were investigated by ultra-high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS/MS)-based metabolomics. The results showed that sulphur fumigation significantly altered the holistic chemical profile of ginger by triggering chemical transformations of certain original components. 6-Gingesulphonic acid, previously reported as a naturally-occurring component in ginger, was revealed to be a sulphur fumigation-induced artificial derivative, which was deduced to be generated by electrophilic addition of 6-shogaol to sulphurous acid. Using UHPLC-QTOF-MS/MS extracting ion analysis with 6-gingesulphonic acid as a characteristic chemical marker, all the commercial ginger samples inspected were determined to be sulphur-fumigated. The research outcomes provide a chemical basis for further comprehensive safety and efficacy evaluations of sulphur-fumigated ginger. Copyright © 2017 Elsevier Ltd. All rights reserved.

Analyses on the formation of atmospheric particles and stabilized sulphuric acid clusters

Energy Technology Data Exchange (ETDEWEB)

Paasonen, P.

2012-11-01

Aerosol particles have various effects on our life. They affect the visibility and have diverse health effects, but are also applied in various applications, from drug inhalators to pesticides. Additionally, aerosol particles have manifold effects on the Earths' radiation budget and thus on the climate. The strength of the aerosol climate effect is one of the factors causing major uncertainties in the global climate models predicting the future climate change. Aerosol particles are emitted to atmosphere from various anthropogenic and biogenic sources, but they are also formed from precursor vapours in many parts of the world in a process called atmospheric new particle formation (NPF). The uncertainties in aerosol climate effect are partly due to the current lack of knowledge of the mechanisms governing the atmospheric NPF. It is known that gas phase sulphuric acid most certainly plays an important role in atmospheric NPF. However, also other vapours are needed in NPF, but the exact roles or even identities of these vapours are currently not exactly known. In this thesis I present some of the recent advancements in understanding of the atmospheric NPF in terms of the roles of the participating vapours and the meteorological conditions. Since direct measurements of new particle formation rate in the initial size scale of the formed particles (below 2 nm) are so far infrequent in both spatial and temporal scales, indirect methods are needed. The work presented on the following pages approaches the NPF from two directions: by analysing the observed formation rates of particles after they have grown to sizes measurable with widely applied instruments (2 nm or larger), and by measuring and modelling the initial sulphuric acid cluster formation. The obtained results can be summarized as follows. (1) The observed atmospheric new particle formation rates are typically connected with sulphuric acid concentration to the power close to two. (2) Also other compounds, most

Effect of Nitric and Oxalic Acid Addition on Hard Anodizing of AlCu4Mg1 in Sulphuric Acid

Directory of Open Access Journals (Sweden)

Maximilian Sieber

2018-02-01

Full Text Available The anodic oxidation process is an established means for the improvement of the wear and corrosion resistance of high-strength aluminum alloys. For high-strength aluminum-copper alloys of the 2000 series, both the current efficiency of the anodic oxidation process and the hardness of the oxide coatings are significantly reduced in comparison to unalloyed substrates. With regard to this challenge, recent investigations have indicated a beneficial effect of nitric acid addition to the commonly used sulphuric acid electrolytes both in terms of coating properties and process efficiency. The present work investigates the anodic oxidation of the AlCu4Mg1 alloy in a sulphuric acid electrolyte with additions of nitric acid as well as oxalic acid as a reference in a full-factorial design of experiments (DOE. The effect of the electrolyte composition on process efficiency, coating thickness and hardness is established by using response functions. A mechanism for the participation of the nitric acid additive during the oxide formation is proposed. The statistical significance of the results is assessed by an analysis of variance (ANOVA. Eventually, scratch testing is applied in order to evaluate the failure mechanisms and the abrasion resistance of the obtained conversion coatings.

Forest fuel and sulphur

International Nuclear Information System (INIS)

Lundborg, A.

1994-10-01

This report illustrates the sulphur cycle in forest fuel and in the forest ecosystem. The hypothesis is that sulphur dioxide from combustion of forest fuel is not more acidifying than sulphur that is mineralized from tree biomass if it is left in the forest instead of being burnt. The report gives an overview of the sulphur cycle in general together with the acidifying effect of sulphur. The sulphur content in wood biomass is about 1 mg/g in the needles and 0.2-0.3 mg/g in wood. Chipped forest fuel contains 0.2-0.5 mg S/g. A removal of 40 tonnes of felling residues per hectare may contain about 8-30 kg S. The sulphur occurs both in organic, often reduced, form and as sulphate. In situations of high availability to sulphur there will be an increased proportion of sulphate. After combustion some, perhaps half, of the sulphur is left in the ashes, most of which appears to be sulphate. In mineralisation of reduced organic sulphur, of type R-SH, the sulphur is released in the form of sulphide. Hydrogen sulphide, H2S, can be oxidised by microbes to sulphate, which should be acidifying (2 H+ will remain). A very rough estimate suggests that emissions of sulphur dioxide from forest fuel, spread over the period the trees are growing, and on the area from which the trees are taken, corresponds to 0.5% of the sulphur deposition in southern Sweden. Sulphur emissions from biofuel combustion are much lower than Sweden's and the EU's most stringent emission limits for coal. Whole-tree removal with return of ashes will theoretically give a considerable reduction in soil acidity since large quantities of nitrogen are removed and thus the acidifying effect of nitrogen will not occur. This should be of greater importance for forest acidification than the effect of biomass sulphur. 80 refs, numerous tabs

Surface characterisation of ethylene-propylene-diene rubber upon exposure to aqueous acidic solution

DEFF Research Database (Denmark)

Mitra, S.; Ghanbari-Siahkali, Afshin; Kingshott, P.

2006-01-01

but significantly different with respect to molar mass and the presence of long chain branching. Both rubbers contained 5-ethylidene-2-norbomene (ENB) as diene. Solution cast films of pure EPDM samples were exposed in two different acidic solutions, viz. chromosulphuric (Cr (VI)/H2SO4) and sulphuric acid (H2SO4....... Furthermore, 20% Cr (VI)/H2SO4 also attacked the allylic carbon-hydrogen (C-H) bonds of ENB resulting in more oxygenated species on the surface compared to 20% H2SO4 under identical conditions. Cr (VI) in the 20% Cr (VI)/H2SO4 was found to play an important role in alteration of surface chemistry. Studies...

Characterization of dross and its recovery by sulphuric acid leaching

Science.gov (United States)

Rahmani, S. A.; Meidianto, A.; Amal, M. I.; Wismogroho, A. S.; Widayatno, W. B.

2018-03-01

This paper reports the characterization of dross from galvanizing process and its recovery using acidic leaching method. The diffraction profile of dross showed identical peaks with that of ZnO. The X-ray Fluorescence (XRF) analysis identified the content of following metals: Zn, Fe, Mn, Ga, Co, and W. The thermal behaviour examination revealed the existence of some volatiles within the initial sample. The acidic leaching at various concentrations of sulphuric acid was conducted to determine the optimum concentration for zinc recovery and the highest yield of zinc sulphate. It is concluded that the optimum concentration of H2SO4 for this kind of dross is 4 M with 71.9% yield of ZnSO4. The result of leaching process was confirmed by infrared spectrum, where various absorptions corresponding to SO4 2- and Zn-O bands were observed.

Influence of solid loading on D-xylose production through dilute sulphuric acid hydrolysis of olive stones

Directory of Open Access Journals (Sweden)

Cuevas, M.

2015-09-01

Full Text Available The selective hydrolysis of hemicellulose from olive stones was attempted in order to achieve a maximum D-xylose yield. For this aim, batch hydrolysis was conducted under different operating conditions of temperature, acid concentration and solid loading. Firstly, distilled water, sulphuric acid and nitric acid were assessed as hydrolytic agents at different temperatures (200, 205, 210 and 220 °C and at a fixed acid concentration (0.025 M. Sulphuric acid and 200 °C were selected for the subsequent dilute acid hydrolysis optimization based on the obtained D-xylose yields. The combined influence of solid loading (from 29.3 to 170.7 g olive stones into 300 mL acid solution and sulphuric acid concentration (0.006–0.034 M on the release of D-xylose was then estimated by response surface methodology. According to a statistical analysis, both parameters had significant interaction effects on D-xylose production. The results illustrated that the higher the solid loading, the higher the required acid concentration. The decrease in the solid/liquid ratio in the reactor had a positive effect on D-xylose extraction and on the amount of acid used. The optimum solid loading and sulphuric acid concentration were determined to be 50 g (solid/liquid ratio 1/6 and 0.016 M, respectively. Under these conditions, the predicted D-xylose yield (expressed as g of sugar per 100 g of dry matter fed was 20.4 (87.2% of maximum attainable.Se ha desarrollado una hidrólisis selectiva de la fracción hemicelulósica del hueso de aceituna con el fin de obtener el máximo rendimiento de D-xilosa. Para ello las hidrólisis se llevaron a cabo en un reactor discontinuo a distintas condiciones de temperatura, concentración de ácido y carga de sólidos. En primer lugar se evaluó la capacidad hidrolítica del agua destilada y de los ácidos nítrico y sulfúrico a distintas temperaturas (200, 205, 210 y 220°C manteniendo fija la concentración de ácido (0,025 M. A partir de

Investigating the significance of zero-point motion in small molecular clusters of sulphuric acid and water

International Nuclear Information System (INIS)

Stinson, Jake L.; Ford, Ian J.; Kathmann, Shawn M.

2014-01-01

The nucleation of particles from trace gases in the atmosphere is an important source of cloud condensation nuclei, and these are vital for the formation of clouds in view of the high supersaturations required for homogeneous water droplet nucleation. The methods of quantum chemistry have increasingly been employed to model nucleation due to their high accuracy and efficiency in calculating configurational energies; and nucleation rates can be obtained from the associated free energies of particle formation. However, even in such advanced approaches, it is typically assumed that the nuclei have a classical nature, which is questionable for some systems. The importance of zero-point motion (also known as quantum nuclear dynamics) in modelling small clusters of sulphuric acid and water is tested here using the path integral molecular dynamics method at the density functional level of theory. The general effect of zero-point motion is to distort the mean structure slightly, and to promote the extent of proton transfer with respect to classical behaviour. In a particular configuration of one sulphuric acid molecule with three waters, the range of positions explored by a proton between a sulphuric acid and a water molecule at 300 K (a broad range in contrast to the confinement suggested by geometry optimisation at 0 K) is clearly affected by the inclusion of zero point motion, and similar effects are observed for other configurations

Sulphur fertilization influences the sulphur species composition in Allium sativum: sulphomics using HPLC-ICPMS/MS-ESI-MS/MS.

Science.gov (United States)

Raab, Andrea; Ronzan, Marilena; Feldmann, Joerg

2017-10-18

Garlic (A. sativum) contains a large number of small sulphur (S)-containing metabolites, which are important for its taste and smell and vary with A. sativum variety and growth conditions. This study was designed to investigate the influence of different sulphur-fertilization regimes on low molecular weight S-species by attempting the first sulphur mass balance in A. sativum roots and bulbs using HPLC-ICPMS/MS-ESI-MS/MS. Species unspecific quantification of acid soluble S-containing metabolites was achieved using HPLC-ICP-MS/MS. For identification of the compounds, high resolution ESI-MS (Orbitrap LTQ and q-TOF) was used. The plants contained up to 54 separated sulphur-containing compounds, which constitute about 80% of the total sulphur present in A. sativum. The roots and bulbs of A. sativum contained the same compounds, but not necessarily the same amounts and proportions. The S-containing metabolites in the roots reacted more sensitively to manipulations of sulphur fertilization than those compounds in the bulbs. In addition to known compounds (e.g. γ-glutamyl-S-1-propenylcysteine) we were able to identify and partially quantify 31 compounds. Three as yet undescribed S-containing compounds were also identified and quantified for the first time. Putative structures were assigned to the oxidised forms of S-1-propenylmercaptoglutathione, S-2-propenylmercaptoglutathione, S-allyl/propenyl-containing PC-2 and 2-amino-3-[(2-carboxypropyl)sulfanyl]propanoic acid. The parallel use of ICP-MS/MS as a sulphur-specific detector and ESI-MS as a molecular detector simplifies the identification and quantification of sulphur containing metabolites without species specific standards. This non-target analysis approach enables a mass balance approach and identifies the occurrence of the so far unidentified organosulphur compounds. The experiments showed that the sulphur-fertilization regime does not influence sulphur-speciation, but the concentration of some S

Experimental investigation of sulphur isotope partitioning during outgassing of hydrogen sulphide from diluted aqueous solutions and seawater.

Science.gov (United States)

Baune, Claudia; Bottcher, Michael E

2010-12-01

The diffusion of hydrogen sulphide across the sediment-water interface and subsequent liberation to the atmosphere may occur in iron-deficient coastal marine environments with enhanced microbial activity in surface sediments and corresponding accumulation of dissolved H2S in near-surface pore waters. The involvement of analogue processes in periods of global mass extinctions during Earth's history (e.g. at the Permian-Triassic boundary) is currently in discussion [L.R. Kump, A. Pavlov, and M. Arthur,Massive Release of Hydrogen Sulfide to the Surface Ocean and Atmosphere During Intervals of Oceanic Anoxia, Geology 33, 397 (2005)]. The outgassing of H₂S is associated with a fractionation of the stable sulphur isotopes, which has so far only been investigated experimentally at selected acidic and neutral pH values, and no experiments with seawater had been carried out. In this communication, we report on sulphur isotope fractionation that takes place during the experimental degassing of H₂S from aqueous solution by an inert gas (N₂) at 21 °C. Experiments were conducted in the pH range between 2.6 and 10.8, corresponding to the dominance fields of dissolved hydrogen sulphide (H₂S(aq)), bisulphide (HS-(aq)), and mixtures of both sulphide species. Overall isotope enrichment factors between -1.6 and +3.0‰ were observed, with the residual dissolved sulphide being enriched or depleted in ³⁴S compared to the liberated H₂S at low and high pH values, respectively. The difference in the low and high pH isotope fractionation effects can be explained by isotope exchange between H₂S(aq) and HS-(aq) [B. Fry, H. Gest, and J.M. Hayes, Sulfur Isotope Effects Associated with Protonation of HS- and Volatilization of H₂S, Chem. Geol. (Isot. Geosci. Sec.) 58, 253 (1986); R. Geßler and K. von Gehlen, Investigation of Sulfur Isotope Fractionation Between H2S Gas and Aqueous Solutions, Fresenius J. Anal. Chem. 324, 130 (1986)] followed by the subsequent transfer of H�

Sulphur recirculation for reduced boiler corrosion; Minskad pannkorrosion med svavelrecirkulation

Energy Technology Data Exchange (ETDEWEB)

Andersson, Sven; Karlsson, Martin (Goetaverken Miljoe AB, Goeteborg (Sweden)); Blomqvist, Evalena; Baefver, Linda; Claesson, Frida; Davidsson, Kent (SP Sveriges Tekniska Forskningsinstitut, Boraas (Sweden)); Froitzheim, Jan; Pettersson, Jesper; Steenari, Britt-Marie (Chalmers Tekniska Hoegskola, Oorganisk miljoekemi, Goeteborg (Sweden))

2010-03-15

Sulphur recirculation is a new technology for reducing boiler corrosion and dioxin formation, which was demonstrated in full-scale tests performed at the Renova Waste to Energy plant at Saevenaes in Goeteborg (Sweden). Sulphur is recirculated from the flue gas cleaning back to the boiler, which reduces the chloride content of the deposits, which in turn reduces boiler corrosion and dioxin formation. Sulphur dioxide was separated from the flue gas in a wet scrubber by adding hydrogen peroxide, producing sulphuric acid. The sulphuric acid was injected into the furnace using nozzles with atomization air, surrounded by recirculated flue gas for improved mixing. By recirculating the sulphur, the sulphur dioxide concentration was increased in the boiler. Each sulphur atom passed the boiler several times and no external sulphur had to be added. Dioxin, ash, deposits and particle samplings together with 1000 h corrosion probe measurements were performed for normal operation (reference) and with sulphur recirculation respectively. During spring 2009, reference measurements were made and the recirculation system was installed and tested. During autumn 2009, a long term test with sulphur recirculation was made. An SO{sub 2} concentration of approximately 800 mg/m3 (n, d.g.) was maintained in the boiler by the system except during a period of extremely low sulphur content in the waste. The sulphur dioxide stack concentrations have been far below the emission limit. Sulphuric acid dew point measurements have shown that the sulphuric acid dosage did not lead to elevated SO{sub 3} concentrations, which may otherwise lead to low temperature corrosion. The chlorine content of both fly ash and boiler ash decreased and the sulphur content increased during the sulphur recirculation tests. The molar chlorine/sulphur ratio (Cl/S) decreased by two thirds in the fly ash as well as in the boiler ash, except for one sample. With sulphur recirculation in operation, the deposit growth was

Effects of sulphur ion implantation on the electrochemical behaviour of two stainless steels in sulphuric medium

International Nuclear Information System (INIS)

Nader-Roux, J.; Becdelievre, A.M. de; Gaillard, F.; Roux, R.; Becdelievre, J. de

1986-01-01

The electrochemical behaviour in sulphuric acid of two austenitic stainless steels (AISI 304 L and AISI 321) modified by sulphur ion implantation has been studied. Surface analysis of oxygen and sulphur by LEEIXS and XRFS were performed before and after polarization on unimplanted and on implanted samples. I/E curves with implanted steels reveal an important corrosion peak (α peak) recovering widely the active peak of unimplanted samples. For high implanted doses, another peak (β peak) appears in the passive range. High doses implanted steels polarized in the range of the α peak exhibit a sulphur enriched black surface layer. SEM examination of this layer shows it is constituted by flakes rolling up themselves. The formation of a superficial non-protective sulphide layer and the internal stresses of this layer explain the corrosion enhancement of sulphur implanted materials. After dissolution of this layer the behaviour of unimplanted steels is found again. (author)

Kinetics and thermodynamics of aluminium dissolution in 1.0M sulphuric acid containing chloride ions

Energy Technology Data Exchange (ETDEWEB)

Abdel-Gaber, A.M. [Department of Chemistry, Faculty of Science, Alexandria University, P.O. Box 426, Ibrahimia, Alexandria 21321 (Egypt)]. E-mail: ashrafmoustafa@yahoo.com; Abd-El-Nabey, B.A. [Department of Chemistry, Faculty of Science, Alexandria University, P.O. Box 426, Ibrahimia, Alexandria 21321 (Egypt); Sidahmed, I.M. [Department of Chemistry, Faculty of Science, Alexandria University, P.O. Box 426, Ibrahimia, Alexandria 21321 (Egypt); El-Zayady, A.M. [Department of Chemistry, Faculty of Science, Alexandria University, P.O. Box 426, Ibrahimia, Alexandria 21321 (Egypt); Saadawy, M. [Department of Chemistry, Faculty of Science, Alexandria University, P.O. Box 426, Ibrahimia, Alexandria 21321 (Egypt)

2006-08-01

The dissolution of aluminium in 1M sulphuric acid solutions containing different chloride ion concentrations (0.01-0.06M) were studied at 25, 30, 35 and 40deg. C using electrochemical impedance spectroscopy (EIS) technique and polarization curves measurements. The kinetic rate equation, under the experimental condition described, was derived and found to verify the following relationship:V=k{sub obs}K{sub 2}C{sub Cl{sup -}}{sup n}1+K{sub 2}C{sub Cl{sup -}}{sup n}where V is the corrosion rate, k{sub obs} and K{sub 2} are the dissolution rate constant of aluminium oxide-chloride complex and the equilibrium constant of chloride ions adsorbed at aluminium oxide surface, respectively. The kinetic and thermodynamic energy parameters were calculated and their values indicate that chloride ions are chemisorbed onto the aluminium oxide surface and the formation of oxide-chloride complex is the rate-determining step.

Influence of molybdate species on the tartaric acid/sulphuric acid anodic films grown on AA2024 T3 aerospace alloy

Energy Technology Data Exchange (ETDEWEB)

Garcia-Rubio, M. [Departamento de Quimica-Fisica Aplicada, Universidad Autonoma de Madrid, 28049 Madrid (Spain); Department of Surface Technologies, Engineering of Materials and Processes, Airbus Spain, Av. John Lennon s/n 28906 Getafe (Spain); Ocon, P. [Departamento de Quimica-Fisica Aplicada, Universidad Autonoma de Madrid, 28049 Madrid (Spain)], E-mail: pilar.ocon@uam.es; Climent-Font, A. [Departamento de Fisica Aplicada, Universidad Autonoma de Madrid (UAM), 28049 Madrid (Spain); Centro de Micro-Analisis de Materiales (CMAM), Universidad Autonoma de Madrid (UAM), 28049 Madrid (Spain); Smith, R.W. [Unidad de Microanalisis de Materiales, Parque Cientifico de Madrid (PCM), Campus de Cantoblanco, 28049 Madrid (Spain); Curioni, M.; Thompson, G.E.; Skeldon, P. [Corrosion and Protection Centre, School of Materials, University of Manchester, M60 1QD England (United Kingdom); Lavia, A.; Garcia, I. [Department of Surface Technologies, Engineering of Materials and Processes, Airbus Spain, Av. John Lennon s/n 28906 Getafe (Spain)

2009-09-15

AA2024 T3 alloy specimens have been anodised in tartaric acid/sulphuric media and tartaric acid/sulphuric media containing sodium molybdate; molybdate species were added to the anodising bath to enhance further the protection provided by the porous anodic film developed over the macroscopic alloy surface. Morphological characterisation of the anodic films formed in both electrolytes was undertaken using scanning electron and transmission electron microscopies; the chemical compositions of the films were determined by Rutherford backscattering spectroscopy that was complemented by elemental depth profiling using rf-glow discharge optical emission spectrometry. The electrochemical behaviour was evaluated using potentiodynamic polarisations and electrochemical impedance spectroscopy; the corrosion performance was examined after salt spray testing. The porous anodic film morphology was little influenced by the addition of molybdate salt, although thinner films were generated in its presence. Chemical composition of the anodic film was roughly similar; however, addition of sodium molybdate in the anodizing bath resulted in residues of molybdate species in the porous skeleton and improved corrosion resistance measured by electrochemical techniques that was confirmed by salt spray testing.

Influence of molybdate species on the tartaric acid/sulphuric acid anodic films grown on AA2024 T3 aerospace alloy

International Nuclear Information System (INIS)

Garcia-Rubio, M.; Ocon, P.; Climent-Font, A.; Smith, R.W.; Curioni, M.; Thompson, G.E.; Skeldon, P.; Lavia, A.; Garcia, I.

2009-01-01

AA2024 T3 alloy specimens have been anodised in tartaric acid/sulphuric media and tartaric acid/sulphuric media containing sodium molybdate; molybdate species were added to the anodising bath to enhance further the protection provided by the porous anodic film developed over the macroscopic alloy surface. Morphological characterisation of the anodic films formed in both electrolytes was undertaken using scanning electron and transmission electron microscopies; the chemical compositions of the films were determined by Rutherford backscattering spectroscopy that was complemented by elemental depth profiling using rf-glow discharge optical emission spectrometry. The electrochemical behaviour was evaluated using potentiodynamic polarisations and electrochemical impedance spectroscopy; the corrosion performance was examined after salt spray testing. The porous anodic film morphology was little influenced by the addition of molybdate salt, although thinner films were generated in its presence. Chemical composition of the anodic film was roughly similar; however, addition of sodium molybdate in the anodizing bath resulted in residues of molybdate species in the porous skeleton and improved corrosion resistance measured by electrochemical techniques that was confirmed by salt spray testing.

Ergo betters estimates after shaky first years. [Recovery of gold, uranium and sulphuric acid

Energy Technology Data Exchange (ETDEWEB)

1982-05-20

Having completed its fourth year of full operation, East Rand Gold and Uranium (ERGO) has established itself as a succesful low-cost gold producer. The recovering of gold, uranium and sulphuric acid from some old slimes dams has beaten its production estimates for 1981 till the end of March 1982. Overall Ergo has settled down well from its first years of production.

Electrolytes for methanol-air fuel cells. I. The performance of methanol electro-oxidation catalysts in sulphuric acid and phosphoric acid electrolytes

Energy Technology Data Exchange (ETDEWEB)

Andrew, M.R.; McNicol, B.D.; Short, R.T.; Drury, J.S.

1977-03-01

Phosphoric acid and sulphuric acid have been compared as potential electrolytes for methanol-air fuel cells. The performances of typical electro-oxidation catalysts were measured in both electrolytes over a range of concentrations. With all catalysts the activity falls with increasing acid concentration. While this is to some extent due to the decrease in water activity at higher concentrations it seems that with both acids there is significant poisoning of the catalyst. The results can be explained for both electrolytes by assuming that adsorption of undissociated acid poisons the catalyst surfaces and that the reaction rate on the poisoned surfaces is proportional to the water activity.

Mechanism of the transpassive dissolution and secondary passivation of chromium in sulphuric acid solutions

International Nuclear Information System (INIS)

Bojinov, M.; Betova, I.; Raicheff, R.; Fabricius, G.; Laitinen, T.; Saario, T.

1998-01-01

The transpassive dissolution and secondary passivation of Cr in 1..10 M H 2 SO 4 solutions were studied by a combination of different electrochemical methods. The steady-state polarization curves for transpassive dissolution exhibited a Tafel behaviour with a slope being independent on the acid concentration. Lower dissolution rates were measured for higher acid concentrations. Ring-disk measurements showed a release of both soluble Cr(VI) and Cr(III) during transpassivity. Impedance spectra were qualititatively similar in all acid concentrations, comprising one capacitive and two inductive semicircles. A kinetic model comprising two parallel transpassive dissolution paths was consistent with the experimental results. Typical passivation diagrams were observed for Cr in 10 M H 2 SO 4 , and a secondary passive state was established at higher potentials. The formation of the secondary passive film was confirmed by contact electric resistance (CER) measurements. A renewed version of the surface charge approach was consistent with the experimental results in the region of the secondary passivation. (orig.)

Behaviour of Type 316 steel in acidic sulphate solutions at 300-3500C

International Nuclear Information System (INIS)

Newman, J.F.

1987-11-01

Most cation resin beds in service in CEGB power stations, and particularly those in AGR stations, are regenerated with sulphuric acid. Slippage results in trace levels of sulphate passing into the boilers. Previous work has shown that in once-through boilers, feedwater containing 2 μg kg -1 of sulphate could concentrate at localized dry-out sites to form solutions having from 0.1 to 7 wt% of solute. It has been shown also that if the sulphate was present in an acidic solution and it were to be in contact with Type 316 austentitic superheater steel, then intergranular corrosion and intergranular cracking could occur. Previous data, including some unreported results, are tabulated and discussed. The current work had two main objectives. The first was to extend the previous investigations to examine a wider range of acidic sulphate concentrations (as indicated by calculations on the concentration of solute in feedwater), the influence of environment pH, and the effect of sensitization of specimens. The second objective was primarily concerned with elucidating the causes of scatter in the results. This involved examining the influence of electrode potential, the ageing characteristics of the environment, and the method of applying stress to the specimens. (author)

Sulphur output from oil sands : dramatically changing Alberta's sulphur balance

International Nuclear Information System (INIS)

D'Aquin, G.

2008-01-01

This paper discussed sulphur production from Alberta's gas and oil sands industries. While sulfur derived from natural gas production in the province is expected to decline as natural gas reserves diminish, Alberta's oil sands contain high amounts of sulphur. It is not yet known how much sulphur will be produced from the province's oil sands facilities. Alberta had considerable stockpiles of sulphur in the 1970s. By 1980, inventories began to decline. By 1996, output had increased to 7.1 million tonnes. Alberta's sulphur inventory reached 9.7 million tonnes following the collapse of the Soviet Union's government mandated fertilizer industry. In 2006, sulphur supplies in Alberta reached 12 million tonnes. Reduced global output has now lowered sulphur stockpiles. Increases in sulphur prices tend to reduce market demand, and lower prices will not typically change the volume of sulphur produced as a byproduct of oil and gas operations. Bitumen-derived sulphur output is expected to exceed gas-derived sulphur output in the near future. Sulphur from oil sands processing is expected to increase by 5 million tonnes by 2017. Increased sulphur production levels in Alberta will present a significant challenge for all sectors of the hydrocarbon industry. It was concluded that developing a plan for storing, selling or disposing of the sulphur will help to ensure the profitability of oil sands operations

The effects of added sulphur amino acids, threonine and an ideal amino acid ratio on nitrogen metabolism in mature, overweight dogs.

Science.gov (United States)

Bohaty, Robin E; de Godoy, Maria R C; McLeod, Kyle R; Harmon, David L

2012-02-01

The objectives of this study were to investigate the effects of added essential amino acids in conjunction with a dietary lysine/MJ of 0.72 on nitrogen (N) metabolism in dogs. Treatments were; a control diet, a diet that provided an ideal amino acid profile (IAA), a diet with added total sulphur amino acids (TSAA), and a diet with added TSAA and threonine (TT). Diets were fed to eight overweight, mature, female hounds using a replicated 4 x 4 Latin Square design. Food intake was similar across treatments, however, food N intake was higher (p dogs formulated to provide a 0.72 g lysine/MJ ME ratio.

Enhancement of the Inhibitor Efficiency of Atropine Methochloride in Corrosion Control of Mild Steel in Sulphuric Acid

Directory of Open Access Journals (Sweden)

Abida Begum

2008-01-01

Full Text Available The inhibition efficiency and synergistic behaviour of 10-4 M Atropine methochloride was carried out using mass loss and polarisation methods in the presence of (i metal ions, Ni2+ and Cu2+ between 10-2 M to 10-6 M concentrations, (ii different concentrations of metal ions and 10-3 M I-, 10-3 M Cl- and 10-3 M Br- solutions and (iii different metal ions, 10-3M I- and at three different temperatures. The analysis reveals that the inhibition efficiency of Atropine methochloride was maximum at 10-2 M in 5 hours of immersion period. Halides decreased the corrosion rate of mild steel in Sulphuric acid. The decrease is maximum with 10-3 M I-. As the temperature increased from 298K to 308K, the inhibition efficiency gradually decreased. The inhibitor was found to be effective up to 303K

Sulphur in Poland

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Seman Peter

2001-12-01

Full Text Available Poland belongs to one of the last countries with native sulphur mining. Its history begun in 15th century. Deposit area of Tarnobrzeg re-presents 80% of all known sulphur reserves in this country. All of explored deposits in this area were created by metasomatic alteration of sulphur bearing limestones with sulphur mineralised liquids, which arised from melt gypsum. The average content is 25 - 30% of sulphur in Tarnobrzeg area. Considerable parts of deposits are created by calcite and native sulphur. Gypstone, baryte and stroncianite have only minera-logic occurencies. The extensive native sulphur deposits account for 88% of the country´s sulphur production. There were five sulphur mines in operation: Jeziórko, Grêbów, Machów I, Machów II and Basznia, but operations in Basznia were ended in 1992 and Machów and Machów II were liquidated. The sixth mine Osiek is currently producing. Only the Machów I mine operated an open-pit extraction and refining process, the other four mines producing sulphur using a modified Frasch method that gives elemental sulphur of up to 99,9% purity. Sulphur is an important export commodity with foreign sales totalling around 1.5 - 2.5 Mt/y. Modern benefication methods, which allowing to achieve sulphur from hydrocarbons, are causing decrease of native sulphur prices in the world and bringing about reduction of mining activities for this raw material in Poland.

Solving the sulphur situation : research assesses viability of burying sulphur

International Nuclear Information System (INIS)

Proce, B.

2006-01-01

Oil sands mining companies are looking for ways to manage growing levels of sulphur production from the Athabasca region. Infrastructure is not in place to economically transport the sulphur even though there is a global market for it. Sulphur cannot be stockpiled indefinitely as it can react with air to produce sulphur dioxide. Although above-ground sulphur storage has been regulated for more than 30 years, the underground storage of sulphur is still in a research and development phase. Alberta Sulphur Research Ltd. is currently conducting an ongoing experiment in which 100 tonne test blocks have been buried above and below the water table so that surrounding areas could be monitored over a period of years. A series of tests is being conducted to examine changes in pH in water and sulphate levels. A multi-layered engineering casing to contain the sulphur and prevent seepage is also being investigated. Once stored underground, operators also have to consider how the sulphur will be accessed in the future, as it is subject to government royalties. The storage of sulphur may have economic benefits as the product can be sold when prices are high. Most sulphur produced in Alberta is sold as an export product in the United States for use in products such as fertilizer. Shell Canada penetrated the Chinese market in 2001 and has since become one of Canada's largest sulphur exporters. Shell has also introduced a number of products using sulphur, including fertilizers, enhanced asphalt, and concrete. It was concluded that companies must take action now to mitigate future losses and to utilize current markets in order to remain competitive. 3 figs

Extremophiles in Mineral Sulphide Heaps: Some Bacterial Responses to Variable Temperature, Acidity and Solution Composition

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Helen R. Watling

2015-07-01

Full Text Available In heap bioleaching, acidophilic extremophiles contribute to enhanced metal extraction from mineral sulphides through the oxidation of Fe(II and/or reduced inorganic sulphur compounds (RISC, such as elemental sulphur or mineral sulphides, or the degradation of organic compounds derived from the ore, biota or reagents used during mineral processing. The impacts of variable solution acidity and composition, as well as temperature on the three microbiological functions have been examined for up to four bacterial species found in mineral sulphide heaps. The results indicate that bacteria adapt to sufficiently high metal concentrations (Cu, Ni, Co, Zn, As to allow them to function in mineral sulphide heaps and, by engaging alternative metabolic pathways, to extend the solution pH range over which growth is sustained. Fluctuating temperatures during start up in sulphide heaps pose the greatest threat to efficient bacterial colonisation. The large masses of ores in bioleaching heaps mean that high temperatures arising from sulphide oxidation are hard to control initially, when the sulphide content of the ore is greatest. During that period, mesophilic and moderately thermophilic bacteria are markedly reduced in both numbers and activity.

Preparation and characterization compatible pellets for immobilization of colloidal sulphur nanoparticles

Science.gov (United States)

Adlim, M.; Zarlaida, F.; Khaldun, I.; Dewi, R.; Jamilah, M.

2018-03-01

Mercury pollution in atmosphere is dominated by mercury vapour release from coal burning and gold-amalgam separation in gold mining. The initial steps in formulating a compatible mercury absorbent for mercury stabilization was fabrication of pellet supported colloidal sulphur. Sulphur is used to stabilize mercury vapour by formation of metacinnabar that has much lower toxicity. The sulphur reactivity toward mercury vapour can be enhanced by using colloidal sulphur nanoparticles immobilized on compatible pellets. Clay pellets would have heat resistance but in fact, they were less stable in aqueous solution although their stability increased with inclusion of rice husk ash and sawdust or pineapple leaf fibre in the composite. Pellets made of rice husk ash and polyvinyl acetate were stable in water at least for 24 hours. Sulphur from thiosulfate precursor that immobilized onto surface of pellet using chitosan as the stabilizer and the binding agent gave lower sulphur content compared to sulphur from other precursors (sulphur powder and sulphur-CS2). Sulphur from thiosulfate precursor was in form of colloid, has nanosize, and disperse particles on the surface of rice husk ash pellets. Sulphur immobilization methods affect on sulphur particles exposure on the pellet surface.

Investigation of copper(I sulphide leaching in oxidative hydrochloric acid solution

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Branislav Marković

2015-12-01

Full Text Available Present work is focused on the copper (I sulphide leaching with sodium chloride in hydrochloric acid solution and with introduction of gaseous oxygen. Chemical reactions of leaching and their thermodynamic probabilities are predicted based on the literature data and products which were formed during the process and the overall leaching reaction was defined. The influence of temperature and time on the leaching degree of copper was experimentally determined. The quantity of dissolved copper increases with the increase of both investigated parameters. Elemental sulphur was formed as the main leaching product, precipitated at the particle surfaces and chloride ions have a role to disrupt the creation of this passive layer.

Maximum production rate optimization for sulphuric acid decomposition process in tubular plug-flow reactor

International Nuclear Information System (INIS)

Wang, Chao; Chen, Lingen; Xia, Shaojun; Sun, Fengrui

2016-01-01

A sulphuric acid decomposition process in a tubular plug-flow reactor with fixed inlet flow rate and completely controllable exterior wall temperature profile and reactants pressure profile is studied in this paper by using finite-time thermodynamics. The maximum production rate of the aimed product SO 2 and the optimal exterior wall temperature profile and reactants pressure profile are obtained by using nonlinear programming method. Then the optimal reactor with the maximum production rate is compared with the reference reactor with linear exterior wall temperature profile and the optimal reactor with minimum entropy generation rate. The result shows that the production rate of SO 2 of optimal reactor with the maximum production rate has an increase of more than 7%. The optimization of temperature profile has little influence on the production rate while the optimization of reactants pressure profile can significantly increase the production rate. The results obtained may provide some guidelines for the design of real tubular reactors. - Highlights: • Sulphuric acid decomposition process in tubular plug-flow reactor is studied. • Fixed inlet flow rate and controllable temperature and pressure profiles are set. • Maximum production rate of aimed product SO 2 is obtained. • Corresponding optimal temperature and pressure profiles are derived. • Production rate of SO 2 of optimal reactor increases by 7%.

Effect of sulphur forms on colour and residue of sulphur during the storage at drying grapes by sulphur

Directory of Open Access Journals (Sweden)

Boztepe Özlem

2016-01-01

Full Text Available Turkey is the world leader in the manufacture and export of seedless raisins. Requirement of golden bleached raisins is increasing in food Industry of especially cake, bread and pastry year by year. In this research, the lowest residual value and the practical realization of such production was intended to determine by drying grapes with application of sulphur. In this case, sulphur residue and colour situations were determined during 12-mounth-storage according to sulphur forms. In this study sulphur studies were applied by Vitis Vinifera cv. “Sultani Çekirdeksiz” with Na2S2O5, which is liquid source of sulphur and SO2, which is gas source of sulphur. SO2 application were studied during 3, 6 and 8 hours and liquid form of sulphur is Na2S2O5 that was used during by 10, 20 and 30 minutes. Applications were prepared with 3 replicates which contain 20 kg fresh grape in each replicate. In conclusion, changes in dried grape have been identified in point of colour (chroma and hue and the sulphur content was determined according to sulphur forms in packing. Gas form of sulphur (SO2 which was applied 3 hours, gave the best result during 12-mounth-storage for colour and sulphur residue.

Indium flotation from hydrometallurgical solutions

International Nuclear Information System (INIS)

Sviridov, V.V.; Mal'tsev, G.I.; Petryakova, N.K.; Gomzikov, A.I.

1980-01-01

The principal possibility of flotation of indium small quantities (10 -4 gxion/l) is established from sulphuric-acid solutions of leaching converter dusts of the copper melting production in the form of complex compounds with sodium hexametaphosphate and cation-active nitrogen-containing surfactants. It is shown that the flotation process effectiveness is determined by the molar ratio of hexametaphosphate and collector introduced into the solution, solution oxidity and surfactant nature

Reinforced sulphur concrete

NARCIS (Netherlands)

2014-01-01

Reinforced sulphur concrete wherein one or more metal reinforcing members are in contact with sulphur concrete is disclosed. The reinforced sulphur concrete comprises an adhesion promoter that enhances the interaction between the sulphur and the one or more metal reinforcing members.

Determination of sulphur with total reflection x-ray spectrometry

International Nuclear Information System (INIS)

Steinmeyer, S.; Kolbesen, B.O.

2000-01-01

The potential and limitations of total reflection x-ray spectrometry (TXRF) were tested for the quantitative determination of the light element sulphur in inorganic and biological samples. As representatives of inorganic samples alkali, transition metal, magnesium and aluminum sulphates were investigated. As biological samples the sulphur containing amino acid methionine and the pharmaceutical drug insulin were chosen. All measurements were performed on a TXRF-spectrometer EXTRA IIA (Atomika Instruments, Oberschleissheim/Germany) using tungsten L-radiation as the excitation tube. Various concentrations of all samples ranging from 20 mg/l to 0.5 mg/l were determined. In addition the surface topography and thickness of the dry residue of these samples were investigated with SEM and a thickness profilometer (Alpha-Step). The result show that the reliable determination of sulphur in sulphates depends on the cation involved. Alkali sulphates like Na 2 SO 4 , or K 2 SO 4 form bulky residues resulting in significant deviations of the recovery rate of sulphur. In this case the use of smoothing detergents like 1 % HF, 1 % malic acid and 2 % hydrazinhydrat was found to be necessary for accurate determination. The results for the biological samples agree well with the expected values. The investigations lead to the conclusion that TXRF combined with a proper samples preparation is well suited for the determination of sulphur in different samples with various concentrations and matrices. (author)

Interaction of magnesium diboride with HΛ2O, HΛ2OΛ2 and with acids

International Nuclear Information System (INIS)

Lyashenko, V.I.; Kosolapova, T.Ya.; Serebryakova, T.I.

1985-01-01

Chemical stability of magnesium diboride in some agressive media is investigated. It is shown that magnesium diboride possesses high chemical activity in relation to acids (nitric, phosphoric, hydrochloric, sulphuric). The fluohydric acid and hydrogen peroxide completely decompose magnesium boride. The kinetics of MgB 2 decomposition in aqueous solutions of acids (hydrochloric, sulphuric, nitric) and in water is studied. Activation energies and solubility rate constants are calculated

Sulphur output from oil sands : dramatically changing Alberta's sulphur balance

Energy Technology Data Exchange (ETDEWEB)

D' Aquin, G. [Con-Sul Inc., Bigfork, MT (United States)

2008-07-01

This paper discussed sulphur production from Alberta's gas and oil sands industries. While sulfur derived from natural gas production in the province is expected to decline as natural gas reserves diminish, Alberta's oil sands contain high amounts of sulphur. It is not yet known how much sulphur will be produced from the province's oil sands facilities. Alberta had considerable stockpiles of sulphur in the 1970s. By 1980, inventories began to decline. By 1996, output had increased to 7.1 million tonnes. Alberta's sulphur inventory reached 9.7 million tonnes following the collapse of the Soviet Union's government mandated fertilizer industry. In 2006, sulphur supplies in Alberta reached 12 million tonnes. Reduced global output has now lowered sulphur stockpiles. Increases in sulphur prices tend to reduce market demand, and lower prices will not typically change the volume of sulphur produced as a byproduct of oil and gas operations. Bitumen-derived sulphur output is expected to exceed gas-derived sulphur output in the near future. Sulphur from oil sands processing is expected to increase by 5 million tonnes by 2017. Increased sulphur production levels in Alberta will present a significant challenge for all sectors of the hydrocarbon industry. It was concluded that developing a plan for storing, selling or disposing of the sulphur will help to ensure the profitability of oil sands operations.

Gas chromatography and silver-ion high-performance liquid chromatography analysis of conjugated linoleic acid isomers in free fatty acid form using sulphuric acid in methanol as catalyst.

Science.gov (United States)

Luna, Pilar; Juárez, Manuela; de la Fuente, Miguel Angel

2008-09-12

This study used GC and silver-ion HPLC to examine the effects of temperature and time on methylation of individual and mixtures of conjugated linoleic acid (CLA) isomers in free fatty acid form using sulphuric acid as catalyst. In the conditions tested (temperatures between 20 and 50 degrees C and times between 10 and 60 min) methylation was complete while avoiding isomerization of conjugated dienes and the formation of artefacts that could interfere with chromatographic determinations. An analytical method using solvent extraction of the lipids followed by selective elution of the free fatty acids from aminopropyl bonded phase columns and methylation with H(2)SO(4) in mild conditions was then applied to determine the CLA isomers in free fatty acid form in rumen fluid, and the results were evaluated.

Morphology and evolution of sulphuric acid caves in South Italy

Science.gov (United States)

D'Angeli, Ilenia M.; De Waele, Jo; Galdenzi, Sandro; Madonia, Giuliana; Parise, Mario; Vattano, Marco

2016-04-01

Sulphuric acid speleogenesis (SAS) related to the upwelling of acid water enriched in H2S and CO2 represents an unusual way of cave development. Since meteoric infiltration waters are not necessarily involved in speleogenesis, caves can form without the typical associated karst expressions (i.e. dolines) at the surface. The main mechanism of sulphuric acid dissolution is the oxidation of H2S (Jones et al., 2015) which can be amplified by bacterial mediation (Engel et al., 2004). In these conditions, carbonate dissolution associated with gypsum replacement, is generally believed to be faster than the normal epigenic one (De Waele et al., 2016). In Italy several SAS caves have been identified, but only few systems have been studied in detail: Frasassi and Acquasanta Terme (Marche)(Galdenzi et al., 2010), Monte Cucco (Umbria) (Galdenzi & Menichetti, 1995), and Montecchio (Tuscany) (Piccini et al., 2015). Other preliminary studies have been carried out in Calabria (Galdenzi, 2007) and Sicily (De Waele et al., 2016). Several less studied SAS cave systems located in South Italy, and in particular in Apulia (Santa Cesarea Terme), Sicily (Acqua Fitusa, Acqua Mintina) and Calabria (Mt. Sellaro and Cassano allo Ionio) have been selected in the framework of a PhD thesis on SAS caves and their speleogenesis. Using both limestone tablet weight loss (Galdenzi et al., 2012) and micro erosion meter (MEM) (Furlani et al., 2010) methods the dissolution rate above and under water in the caves will be quantified. Geomorphological observations, landscape analysis using GIS tools, and the analysis of gypsum and other secondary minerals (alunite and jarosite) (stable isotopes and dating) will help to reconstruct the speleogenetic stages of cave formation. Preliminary microbiological analysis will determine the microbial diversity and ecology in the biofilms. References Engel S.A., Stern L.A., Bennett P.C., 2004 - Microbial contributions to cave formation: New insight into sulfuric acid

Sulphur mustard degradation on zirconium doped Ti-Fe oxides

Energy Technology Data Exchange (ETDEWEB)

Stengl, Vaclav, E-mail: stengl@iic.cas.cz [Department of Solid State Chemistry, Institute of Inorganic Chemistry AS CR v.v.i 250 68 Husinec-Rez (Czech Republic); Grygar, Tomas Matys [Department of Solid State Chemistry, Institute of Inorganic Chemistry AS CR v.v.i 250 68 Husinec-Rez (Czech Republic); Oplustil, Frantisek; Nemec, Tomas [Military Technical Institute of Protection Brno Veslarska 230, 628 00 Brno (Czech Republic)

2011-09-15

Highlights: {yields} New stechiometric materials for sulphur mustard degradation. {yields} High degree of degradation, more then 95% h{sup -1}. {yields} One-pot synthesis procedure. - Abstract: Zirconium doped mixed nanodispersive oxides of Ti and Fe were prepared by homogeneous hydrolysis of sulphate salts with urea in aqueous solutions. Synthesized nanodispersive metal oxide hydroxides were characterised as the Brunauer-Emmett-Teller (BET) surface area and Barrett-Joiner-Halenda porosity (BJH), X-ray diffraction (XRD), infrared (IR) spectroscopy, scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) microanalysis, and acid-base titration. These oxides were taken for an experimental evaluation of their reactivity with sulphur mustard (chemical warfare agent HD or bis(2-chloroethyl)sulphide). The presence of Zr{sup 4+} dopant tends to increase both the surface area and the surface hydroxylation of the resulting doped oxides in such a manner that it can contribute to enabling the substrate adsorption at the oxide surface and thus accelerate the rate of degradation of warfare agents. The addition of Zr{sup 4+} to the hydrolysis of ferric sulphate with urea shifts the reaction route and promotes formation of goethite at the expense of ferrihydrite. We discovered that Zr{sup 4+} doped oxo-hydroxides of Ti and Fe exhibit a higher degradation activity towards sulphur mustard than any other yet reported reactive sorbents. The reaction rate constant of the slower parallel reaction of the most efficient reactive sorbents is increased with the increasing amount of surface base sites.

Sulphur uptake and yield of soybean as influenced by sulphur fertilization

International Nuclear Information System (INIS)

Shamima, N.; Farid, A. T. M.

2005-01-01

Effect of sulphur fertilization (0, 20, 40, 60 and 80 kg/ha) on sulphur uptake and seed yield was studied in sohag and Bangladesh soybean-4 varieties in the field of Bangladesh Agricultural Research Institute, Gazipur during the winter (rabi) seasons of 2000-2001 and 2001-2002 in grey Terrace soil (Albaquept). Addition of slphur fertilizer exerted significant influence on the yield attributes of soybean varieties. Sulphur uptake also significantly responded to the application of sulphur fertilizer. Variety Bangladesh soybean-4 was found superior to sohag in respect of sulphur uptake and yield. Greater sulphur utilization was observed at lower levels of fertilizer application. Seed yield and sulphur uptake were increased with the application of 40 kg/ ha for sohag and 60 kg/ha for Bangladesh soybean-4. Response of seed yield to added sulphur was quadratic. The economic optimum doses were found to be 49 kg s/ha for sohag and 52 kg s/ha for Bangladesh soybean-4, yielding 2060 and 2354 kg/ha, respectively. (author)

Uranium adsorption from the sulphuric acid leach liquor containing more chlorides with cation-exchange resin SL-406

International Nuclear Information System (INIS)

Hu Jun; Wang Zhaoguo; Chi Renqing; Niu Xuejun

1994-01-01

The feasibility of uranium adsorption was studied from the sulphuric acid leach liquor of a uranium ore containing more chlorides with cation-exchange resin SL-406. The influence of some factors on uranium adsorption was investigated. It was shown that the resin possesses better selectivity, stability and higher capacity. It can be effectively used to recovery uranium from leach liquors of uranium ores containing more chlorides

Acid-catalysed xylose dehydration into furfural in the presence of kraft lignin.

Science.gov (United States)

Lamminpää, Kaisa; Ahola, Juha; Tanskanen, Juha

2015-02-01

In this study, the effects of kraft lignin (Indulin AT) on acid-catalysed xylose dehydration into furfural were studied in formic and sulphuric acids. The study was done using D-optimal design. Three variables in both acids were included in the design: time (20-80 min), temperature (160-180°C) and initial lignin concentration (0-20 g/l). The dependent variables were xylose conversion, furfural yield, furfural selectivity and pH change. The results showed that the xylose conversion and furfural yield decreased in sulphuric acid, while in formic acid the changes were minor. Additionally, it was showed that lignin has an acid-neutralising capacity, and the added lignin increased the pH of reactant solutions in both acids. The pH rise was considerably lower in formic acid than in sulphuric acid. However, the higher pH did not explain all the changes in conversion and yield, and thus lignin evidently inhibits the formation of furfural. Copyright © 2014 Elsevier Ltd. All rights reserved.

Nitrogen and Sulphur Relations in Effecting Yield and Quality of Cereals and Oilseed Crops

Directory of Open Access Journals (Sweden)

B.K. Nad

2001-01-01

Full Text Available Nitrogen and sulphur, both vital structural elements, are especially needed for the synthesis of proteins and oils. Investigations revealed the required application of sulphur is one half to one third the amount of nitrogen, and the ratio becomes narrower in mustard (Brassica juncea L., followed by wheat and rice. The efficiency of an increased level of nitrogen required a proportionately higher amount of sulphur. A critical investigation on the effective utilization of applied vis-à-vis absorbed nitrogen in wheat and mustard envisaged accumulation of NO3-N in vegetative parts when sulphur remained proportionately low. Application of sulphur hastened the chemical reduction of absorbed NO3– for its effective utilization. The effect was more pronounced in mustard than in wheat. Easily available forms of sulphur, like ammonium sulphate and gypsum, as compared to pyrite or elemental sulphur, maintained adequate N to S ratio in rice, resulting in a reduction in the percent of unfilled grain, a major consideration in rice yield. A narrow N to S ratio, with both at higher levels, increased the oil content but raised the saponification value of the oil, a measure of free fatty acids. Whereas, a proportionately narrow N to S ratio at moderate dose resulted in adequately higher seed and oil yield with relatively low saponification value, associated with increased iodine value of the oil, indicating respectively low free fatty acids and higher proportion of unsaturated fatty acids, an index for better quality of the oil.

Growth and yield response of sunflower (helianthus annuus l.) to sulphur and boron application

International Nuclear Information System (INIS)

Tahir, M.; Shah, S.A.; Tanveer, A.; Rehman, H.U.

2014-01-01

An experiment was conducted to study the growth and yield response of sunflower to sulphur and boron application. Sulphur (control, 15, 30 kg/ha) and foliar sprays of 1% boron solution (control, spray at 4 week after emergence, 20 days after first spray, at 4 weeks after germination + 20 days after first spray) was applied in soil. The results showed significant increase of all growth and yield parameters by varying levels of sulphur and boron application. Application of 30 kg sulphur/ha enhanced stem diameter (1.99 cm), number of achene per head (765.75) and oil content (36.42%). In case of combined use of sulphur and boron application, maximum plant height (171 cm), head diameter (20.71 cm), 1000-achene weight (54.56 g), biological yield (16.49 t/ha) and achene yield (3.99 t/ha) was recorded by the application of 2 sprays of boron solution (1%) at 4 weeks after germination and reproductive stage. (author)

LEACH ARCILLAS ACTIVATED PARTIAL ACID SULFURICO

OpenAIRE

Romero Y Otiniano, P.; Pizarra Cabrera, R.

2014-01-01

This work is concerned with the activation of calcium bentonite from Junín- Perú (with a moisture content of 24.1% and an average of particle size 40 µ ) with sulphuric acid. The parameters studied are the ratio of bentonite to acid solution, acid concentration and reaction time to boiling temperatura of the mixture. The optimum conditions obtained are the following: 0.47 kg. of bentonite/kg. of acid solution to 4.8 N, 4 h of treatment to 104 ºC and the conversion of 45.6% alumina and 73.5% o...

Effects of sulphuric acid pollution on the biology of streams in the Transvaal, South Africa

Energy Technology Data Exchange (ETDEWEB)

Harrison, A D

1958-01-01

Strongly acid effluents or drainage waters are produced during gold and coal mining activities in the Transvaal. Sulphuric acid is produced during oxidation of pyrites exposed by mining operations and much of it finds its way into streams and creates serious pollution problems. The object of this paper is to give a short account of the effects of this acid pollution on the biology of these streams. The first streams considered are the Klip and Klipspruit near their confluence at Olifantsvlei, near Johannesburg. These were studied during a two-year investigation of the area. Both receive acid pollution from gold mine dumps and slimes dams, the seepages from which have pH values as low as 2.3. Both streams run over dolomite formations so the acid is gradually neutralised but highly mineralised, permanently hard water results. The Klip and the Klipspruit join in the middle of a y-shaped, swampy area, each stream coming down one of the upper arms of the y. A sampling station was set up on each where it runs slowly through the swamp just before confluence.

The impact of UV-B and sulphur- or copper-containing solutions in acidic conditions on chlorophyll fluorescence in selected Ramalina species

International Nuclear Information System (INIS)

Garty, J.; Tamir, O.; Levin, T.; Lehr, H.

2007-01-01

Ramalina maciformis and Ramalina lacera were exposed to different solutions and UV-B to seek for alterations in the PSII photosynthetic quantum yield (F v /F m ), in response to chemicals and radiation. For R. maciformis, significant alterations of the F v /F m ratio occurred only in response to different bisulphite solutions. The F v /F m ratio decreased most in R. maciformis and R. lacera following exposure to 5 and 1 mM bisulphite, respectively. Significant differences in F v /F m ratios were observed for R. lacera in response to different solutions and light at different wavelengths, this being synergistic. The PSII system was unaffected by simulated acid rain in both lichens. R. maciformis, in particular, may survive limited acid rain exposure owing to high Ca oxalate accumulation. The F v /F m ratio decreased most in R. lacera following short-term exposures to CuSO 4 , suggesting that this species is more sensitive to Cu ions under acidic conditions. - Lichens in the eastern Mediterranean tolerate acid rain owing to high Ca content in the thallus, but are sensitive to bisulphite

Hydrofluoric–nitric–sulphuric-acid surface treatment of tungsten for carbon fibre-reinforced composite hybrids in space applications

Energy Technology Data Exchange (ETDEWEB)

Kanerva, M., E-mail: Mikko.Kanerva@aalto.fi [Aalto University, School of Engineering, Department of Applied Mechanics, P.O.B. 14300, FI-00076 Aalto (Finland); Johansson, L.-S.; Campbell, J.M. [Aalto University, School of Chemical Technology, Department of Forest Products Technology, P.O.B. 16300, FI-00076 Aalto (Finland); Revitzer, H. [Aalto University, School of Chemical Technology, Department of Chemistry, P.O.B. 16300, FI-00076 Aalto (Finland); Sarlin, E. [Tampere University of Technology, Department of Materials Science, P.O.B. 589, FI-33101 Tampere (Finland); Brander, T.; Saarela, O. [Aalto University, School of Engineering, Department of Applied Mechanics, P.O.B. 14300, FI-00076 Aalto (Finland)

2015-02-15

Highlights: • XPS and AFM analysis of the effect of hydrofluoric–nitric–sulphuric-acid on tungsten. • Dreiling's model established 54.4% thinning of WO{sub 3} due to 67 s treatment. • Strain energy release rate increased ≈8.4 J/m{sup 2} at the interface. • Failure loci analysis expressed the oxide and carbon fibre surfaces as weak points. - Abstract: Hybrid material systems, such as combinations of tungsten foils and carbon fibre-reinforced plastic (CFRP), are replacing metal alloy concepts in spacecraft enclosures. However, a good adhesion between the tungsten oxide scale and the epoxy resin used is required. Here, the effects of a hydrofluoric–nitric–sulphuric-acid (HFNS) treatment on tungsten oxides and subsequent adhesion to CFRP are analysed using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and fracture testing. The work shows that HFNS treatment results in decreased oxygen content, over 50% thinner tungsten trioxide (WO{sub 3}) layer and increased nano-roughness on thin tungsten foils. Fracture testing established a 39% increase in the average critical strain for tungsten–CFRP specimens after HFNS treatment was carried out on tungsten. The effect of the oxide scale modification regarding the critical strain energy release rate was ΔG{sub c}≈ 8.4 J/m{sup 2}.

Sulphur cement pre-composition and process for preparing such sulphur cement pre-composition

NARCIS (Netherlands)

2013-01-01

The invention provides a process for the preparation of a sulphur cement pre-composition comprising reacting sulphur modifier with polysulphide-containing organosilane to obtain in the presence of sulphur the sulphur cement pre-composition, wherein the organosilane has the general molecular formula:

Reactions of sulphur mustard on impregnated carbons.

Science.gov (United States)

Prasad, G K; Singh, Beer

2004-12-31

Activated carbon of surface area 1100 m2/gm is impregnated with 4% sodium hydroxide plus 3% Cr(VI) as CrO3 with and without 5% ethylene diamine (EDA), 4% magnesium nitrate and 5% ruthenium chloride by using their aqueous solutions. These carbons are characterized for surface area analysis by BET conventional method and exposed to the vapours of sulphur mustard (HD) at room temperature (30 degrees C). After 24 h, the reaction products are extracted in dichloromethane and analyzed using gas chromatography and mass spectrometry (GC-MS). Hemisulphur mustard, thiodiglycol, 1,4-oxathiane are observed to be the products of reaction between sulphur mustard and NaOH/CrO3/C system, whereas on NaOH/CrO3/EDA/C system HD reacted to give 1,4-thiazane. On Mg(NO3)2/C system it gave hemisulphur mustard and thiodiglycol. On RuCl3/C system it degraded to divinyl sulphone. Residual sulphur mustard is observed along with reaction products in all systems studied. Reaction mechanisms are also proposed for these interesting surface reactions. Above-mentioned carbons can be used in filtration systems for protection against hazardous gases such as sulphur mustard.

Reactions of sulphur mustard on impregnated carbons

International Nuclear Information System (INIS)

Prasad, G.K.; Singh, Beer

2004-01-01

Activated carbon of surface area 1100 m 2 /gm is impregnated with 4% sodium hydroxide plus 3% Cr(Vi) as CrO 3 with and without 5% ethylene diamine (EDA), 4% magnesium nitrate and 5% ruthenium chloride by using their aqueous solutions. These carbons are characterized for surface area analysis by BET conventional method and exposed to the vapours of sulphur mustard (HD) at room temperature (30 deg. C). After 24 h, the reaction products are extracted in dichloromethane and analyzed using gas chromatography and mass spectrometry (GC-MS). Hemisulphur mustard, thiodiglycol, 1,4-oxathiane are observed to be the products of reaction between sulphur mustard and NaOH/CrO 3 /C system, whereas on NaOH/CrO 3 /EDA/C system HD reacted to give 1,4-thiazane. On Mg(NO 3 ) 2 /C system it gave hemisulphur mustard and thiodiglycol. On RuCl 3 /C system it degraded to divinyl sulphone. Residual sulphur mustard is observed along with reaction products in all systems studied. Reaction mechanisms are also proposed for these interesting surface reactions. Above-mentioned carbons can be used in filtration systems for protection against hazardous gases such as sulphur mustard

Leaching of a Cu-Co ore from Congo using sulphuric acidhydrogen peroxide leachants

Directory of Open Access Journals (Sweden)

Seo S.Y.

2013-01-01

Full Text Available A Cu-Co ore from Katinga Province, the Republic of Congo containing 1.5% Co and 1.6% Cu was tested to determine the leachability of Cu and Co using sulphuric acid and hydrogen peroxide mixtures at different conditions. Without hydrogen peroxide, the maximum extraction of copper and cobalt were found to be ~80% and ~15%, respectively when the acid concentration was varied between 0.36 - 1.1M. When hydrogen peroxide was added (0.008-0.042M, Cu recovery was enhanced to ~90%. Recoveries of ~90% of Co could be achieved at 20ºC, using leachants consisting of 0.36M sulphuric acid and 0.025M hydrogen peroxide after 3 hours. The reaction time to reach 90% Co extraction was reduced to less than 2 hours at 30ºC. Stabcal modelling of the Eh-pH diagrams shows the importance of hydrogen peroxide as a reductant. The decrease of solution potential (300-350 mV by adding hydrogen peroxide was confirmed by Eh measurements during the tests. The leaching follows the shrinking core model kinetics, where the rate constant is linearly dependent on hydrogen peroxide concentration in the range 0-0.025M and proportional to (1/r2 where r is the average radius of the mineral particles. The activation energy for the leaching process is 72.3 kJ/mol.

Use of PSA for design of emergency mitigation systems in a hydrogen production plant using General Atomics SI cycle technology. Section 2: Sulphuric acid decomposition

International Nuclear Information System (INIS)

Mendoza, A.; Nelson, P.F.; Francois, J.L.

2010-01-01

Throughout the past decades, the need to reduce greenhouse gas emissions has prompted the development of technologies for the production of clean fuels through the use of zero emissions primary energy resources, such as heat from high temperature nuclear reactors. One of the most promising of these technologies is the generation of hydrogen by the sulphur-iodine cycle coupled to a high temperature nuclear reactor, initially proposed by General Atomics. By its nature and because these will have to be large-scale plants, development of these technologies from its current phase to its procurement and construction phase, will have to incorporate emergency mitigation systems in all its sections and nuclear-chemical 'tie-in points' to prevent unwanted events that can compromise the integrity of the plant and the nearby population centres. For the particular case of the SI thermochemical cycle, a large number of safety studies have been developed; however, most of these studies have focused on hydrogen explosions and failures in the primary cooling system. While these are the most catastrophic events, it is also true that there are many other events that without having a direct impact on the nuclear-chemical coupling, could jeopardise plant operations, safety of people in nearby communities and bring economic consequences. This study examined one of these events, which is the formation of a toxic cloud driven by an uncontrolled leakage of concentrated sulphuric acid in the second section of the General Atomics SI cycle. In this section, the concentration of sulphuric acid is close to 90% in conditions of high temperature and positive pressure. Under these conditions, sulphuric acid and sulphur oxides from the reactor would immediately form a toxic cloud, that in contact with operators could cause fatalities, or could produce choking, respiratory problems and eye irritation to people in neighbouring towns. The methodology used for this analysis is the design based on

Design and modeling of an advanced marine machinery system including waste heat recovery and removal of sulphur oxides

DEFF Research Database (Denmark)

Frimann Nielsen, Rasmus; Haglind, Fredrik; Larsen, Ulrik

2014-01-01

the efficiency of machinery systems. The wet sulphuric acid process is an effective way of removing flue gas sulphur oxides from land-based coal-fired power plants. Moreover, organic Rankine cycles (ORC) are suitable for heat to power conversion for low temperature heat sources. This paper describes the design...... that an ORC placed after the conventional waste heat recovery system is able to extract the sulphuric acid from the exhaust gas, while at the same time increase the combined cycle thermal efficiency by 2.6%. The findings indicate that the technology has potential in marine applications regarding both energy...... and modeling of a highly efficient machinery system which includes the removal of exhaust gas sulphur oxides. The system consists of a two-stroke diesel engine, the wet sulphuric process for sulphur removal, a conventional steam Rankine cycle and an ORC. Results of numerical modeling efforts suggest...

Optimization of the 3-Point Bending Failure of Anodized Aluminum Formed in Tartaric/Sulphuric Acid Using Doehlert Design

Science.gov (United States)

Bensalah, W.; Feki, M.; De-Petris Wery, M.; Ayedi, H. F.

2015-02-01

The bending failure of anodized aluminum in tartaric/sulphuric acid bath was modeled using Doehlert design. Bath temperature, anodic current density, sulphuric acid, and tartaric acid concentrations were retained as variables. Thickness measurements and 3-point bending experiments were conducted. The deflection at failure ( D f) and the maximum load ( F m) of each sample were, then, deducted from the corresponding flexural responses. The treatment of experimental results has established mathematical models of second degree reflecting the relation of cause and effect between the factors and the studied properties. The optimum path study of thickness, deflection at failure, and maximum load, showed that the three optima were opposite. Multicriteria optimization using the desirability function was achieved in order to maximize simultaneously the three responses. The optimum conditions were: C tar = 18.2 g L-1, T = 17.3 °C, J = 2.37 A dm-2, C sul = 191 g L-1, while the estimated response values were e = 57.7 µm, D f = 5.6 mm, and F m = 835 N. Using the established models, a mathematical correlation was found between deflection at failure and thickness of the anodic oxide layer. Before bending tests, aluminum oxide layer was examined by scanning electron microscopy (SEM) and atomic force microscopy. After tests, the morphology and the composition of the anodic oxide layer were inspected by SEM, optical microscopy, and glow-discharge optical emission spectroscopy.

Effects of acidic deposition on the erosion of carbonate stone - experimental results from the U. S. National Acid Precipitation Assessment Program (NAPAP)

Energy Technology Data Exchange (ETDEWEB)

Baedecker, P.A.; Reddy, M.M.; Reimann, K.J.; Sciammarella, C.A. (US Geological Survey, Reston, VA (USA))

1992-06-01

Test briquettes and slabs of freshly quarried limestone and marble have been exposed to the environment to quantify the incremental effects of wet and dry deposition of hydrogen ion, sulphur dioxide, and nitrogen oxides on stone erosion. Erosion due to grain loss did not seem to be influenced by rainfall acidity, but may be influenced by dry deposition of sulphur dioxide between rainfall events. Chemical analyses of the run-off solutions suggest that around 30% of erosion by dissolution can be attributed to the wet deposition of hydrogen ion and the dry deposition of sulphur dioxide and nitric acid between rain events. The remaining 70% of erosion by dissolution is accounted for by the solubility of carbonate stone in 'clean' rain. 17 refs., 4 figs., 7 tabs.

A method for the gravimetric determination of plutonium in pure plutonium nitrate concentrate solution

International Nuclear Information System (INIS)

Mair, M.A.; Savage, D.J.

1986-12-01

Plutonium nitrate solution is treated with sulphuric acid before being heated and finally ignited. The stoichiometric plutonium dioxide so formed is weighed and hence the plutonium content is calculated. (author)

Molecular understanding of sulphuric acid-amine particle nucleation in the atmosphere

CERN Document Server

Almeida, João; Kürten, Andreas; Ortega, Ismael K; Kupiainen-Määttä, Oona; Praplan, Arnaud P; Adamov, Alexey; Amorim, Antonio; Bianchi, Federico; Breitenlechner, Martin; David, André; Dommen, Josef; Donahue, Neil M; Downard, Andrew; Dunne, Eimear; Duplissy, Jonathan; Ehrhart, Sebastian; Flagan, Richard C; Franchin, Alessandro; Guida, Roberto; Hakala, Jani; Hansel, Armin; Heinritzi, Martin; Henschel, Henning; Jokinen, Tuija; Junninen, Heikki; Kajos, Maija; Kangasluoma, Juha; Keskinen, Helmi; Kupc, Agnieszka; Kurtén, Theo; Kvashin, Alexander N; Laaksonen, Ari; Lehtipalo, Katrianne; Leiminger, Markus; Leppä, Johannes; Loukonen, Ville; Makhmutov, Vladimir; Mathot, Serge; McGrath, Matthew J; Nieminen, Tuomo; Olenius, Tinja; Onnela, Antti; Petäjä, Tuukka; Riccobono, Francesco; Riipinen, Ilona; Rissanen, Matti; Rondo, Linda; Ruuskanen, Taina; Santos, Filipe D; Sarnela, Nina; Schallhart, Simon; Schnitzhofer, Ralf; Seinfeld, John H; Simon, Mario; Sipilä, Mikko; Stozhkov, Yuri; Stratmann, Frank; Tomé, Antonio; Tröstl, Jasmin; Tsagkogeorgas, Georgios; Vaattovaara, Petri; Viisanen, Yrjo; Virtanen, Annele; Vrtala, Aron; Wagner, Paul E; Weingartner, Ernest; Wex, Heike; Williamson, Christina; Wimmer, Daniela; Ye, Penglin; Yli-Juuti, Taina; Carslaw, Kenneth S; Kulmala, Markku; Curtius, Joachim; Baltensperger, Urs; Vehkamaki, Hanna; Kirkby, Jasper

2013-01-01

Nucleation of aerosol particles from trace atmospheric vapours is thought to provide up to half of global cloud condensation nuclei. Aerosols can cause a net cooling of climate by scattering sunlight and by leading to smaller but more numerous cloud droplets, which makes clouds brighter and extends their lifetimes. Atmospheric aerosols derived from human activities are thought to have compensated for a large fraction of the warming caused by greenhouse gases. However, despite its importance for climate, atmospheric nucleation is poorly understood. Recently, it has been shown that sulphuric acid and ammonia cannot explain particle formation rates observed in the lower atmosphere. It is thought that amines may enhance nucleation, but until now there has been no direct evidence for amine ternary nucleation under atmospheric conditions. Here we use the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber at CERN and find that dimethylamine above three parts per trillion by volume can enhance particle formation rates ...

The response of soil solution chemistry in European forests to decreasing acid deposition.

Science.gov (United States)

Johnson, James; Graf Pannatier, Elisabeth; Carnicelli, Stefano; Cecchini, Guia; Clarke, Nicholas; Cools, Nathalie; Hansen, Karin; Meesenburg, Henning; Nieminen, Tiina M; Pihl-Karlsson, Gunilla; Titeux, Hugues; Vanguelova, Elena; Verstraeten, Arne; Vesterdal, Lars; Waldner, Peter; Jonard, Mathieu

2018-03-31

Acid deposition arising from sulphur (S) and nitrogen (N) emissions from fossil fuel combustion and agriculture has contributed to the acidification of terrestrial ecosystems in many regions globally. However, in Europe and North America, S deposition has greatly decreased in recent decades due to emissions controls. In this study, we assessed the response of soil solution chemistry in mineral horizons of European forests to these changes. Trends in pH, acid neutralizing capacity (ANC), major ions, total aluminium (Al tot ) and dissolved organic carbon were determined for the period 1995-2012. Plots with at least 10 years of observations from the ICP Forests monitoring network were used. Trends were assessed for the upper mineral soil (10-20 cm, 104 plots) and subsoil (40-80 cm, 162 plots). There was a large decrease in the concentration of sulphate (SO42-) in soil solution; over a 10-year period (2000-2010), SO42- decreased by 52% at 10-20 cm and 40% at 40-80 cm. Nitrate was unchanged at 10-20 cm but decreased at 40-80 cm. The decrease in acid anions was accompanied by a large and significant decrease in the concentration of the nutrient base cations: calcium, magnesium and potassium (Bc = Ca 2+  + Mg 2+  + K + ) and Al tot over the entire dataset. The response of soil solution acidity was nonuniform. At 10-20 cm, ANC increased in acid-sensitive soils (base saturation ≤10%) indicating a recovery, but ANC decreased in soils with base saturation >10%. At 40-80 cm, ANC remained unchanged in acid-sensitive soils (base saturation ≤20%, pHCaCl2 ≤ 4.5) and decreased in better-buffered soils (base saturation >20%, pHCaCl2 > 4.5). In addition, the molar ratio of Bc to Al tot either did not change or decreased. The results suggest a long-time lag between emission abatement and changes in soil solution acidity and underline the importance of long-term monitoring in evaluating ecosystem response to decreases in deposition. © 2018 John Wiley & Sons

Corrosion Inhibition of Aluminium in Acid Media By Citrullus Colocynthis Extract

OpenAIRE

Chauhan, Rajkiran; Garg, Urvija; Tak, R. K.

2011-01-01

Inhibition of corrosion of aluminium in acid solution by methanol extract of Citrullus colocynthis plant has been studied using mass loss and thermometric measurements. It has been found that the plant extract act as a good corrosion inhibitor for aluminium in all concentrations of sulphuric and hydrochloric acid solution. The inhibition action depends on the concentration of acid and inhibitor. Results for mass loss and thermometric measurement indicate that inhibition efficiency increase wi...

Sumpor u ugljenu (Sulphur in Coal

Directory of Open Access Journals (Sweden)

Rađenović, A.

2004-12-01

Full Text Available The presence of sulphur in coal possesses important environmetal problems in its usage. The sulphur dioxide (S02 emissions produced during coal combustion account for a significant proportion of the total global output of anthropogenic SO2. The extent of sulphur separation depends on several variables such as the form of sulphur in coal, intimacy of contact between minerals and the products of devolatilization. The total sulphur in coal varies in the range of 0.2 - 11 wt %, although in most cases it is beetwen 1 and 3 wt %. Sulphur occurs in a variety of both inorganic and organic forms. Inorganic sulphur is found mainly as iron pyrite, marcasite, pyrrhotite, sphalerite, galena, chalcopirite and as sulphates (rarely exceeds w = 0,1 %. Organic sulphur is found in aromatic rings and aliphatic functionalities usually as mercaptans, aliphatic and aryl sulfides, disulfides and thiophenes. Organic and pyritic sulphur quantities depend on coal rank. Higher rank coals tend to have a high proportion of labile sulphur. All the organic sulphur is bivalent and it is spread throughout the organic coal matrix. Sulphur occurs in all the macerals and most minerals. Vitrinite contains the major part of organic sulphur and metals. Elemental sulphur is produced during coal weathering. The depolymerization methods as pyrolysis and hydrogenation are very drastic methods wich change the structure of the coal and the sulphur groups. In the case of pyrolysis, high levels of desulphurization, in chars and additional production of liquid hydrocarbon can be achieved. Thiophenes and sulphides were the major sulphur components of tars from coal pyrolysis. Hyrdogen sulphide and the lower mercaptans and sulphides were found in the volatile matters. Hydrogen sulphide and thiophenes are practically the only sulphur products of coal hydrogenation. H2S is produced in char hydrodesulphurization. A number of options are available for reducing sulphur emissions including the

Assessing the suitability of Norway spruce wood as an environmental archive for sulphur

International Nuclear Information System (INIS)

Barrelet, T.; Ulrich, A.; Rennenberg, H.; Zwicky, C.N.; Kraehenbuehl, U.

2008-01-01

The aim of this study was to assess the suitability of Norway spruces (Picea abies L. Karst.) as an environmental archive for sulphur. For this purpose spruce trees were sampled in two distinct regions of Switzerland: the Alps and the Swiss Plateau, which differ significantly with respect to S immission. Wood samples were measured using two methods: LASER Ablation high resolution inductively coupled plasma mass spectrometry (LA-HR-ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP-OES) after acid digestion. Independently corroborated by previous measurements of sulphur in peat bogs, the rise and fall of sulphur dioxide pollution in Switzerland appears to be reflected in spruce wood sulphur content. While the wood sulphur content profile of trees sampled in the Alps is relatively flat, the profiles of trees located on the Swiss Plateau display a characteristic sulphur peak. This corresponds to air pollution data in the different regions and indicates that the trees reacted on the changing S supply and recorded a pollution signal in the wood. - Norway spruce is a suitable archive for sulphur when physiological aspects and limitations are taken into account

Steam reforming of commercial ultra-low sulphur diesel

Energy Technology Data Exchange (ETDEWEB)

Boon, J.; Van Dijk, E.; De Munck, S.; Van den Brink, R. [Energy research Centre of The Netherlands, ECN Hydrogen and Clean Fossil Fuels, P.O. Box 1, NL1755ZG Petten (Netherlands)

2011-03-11

Two main routes for small-scale diesel steam reforming exist: low-temperature pre-reforming followed by well-established methane steam reforming on the one hand and direct steam reforming on the other hand. Tests with commercial catalysts and commercially obtained diesel fuels are presented for both processes. The fuels contained up to 6.5 ppmw sulphur and up to 4.5 vol.% of biomass-derived fatty acid methyl ester (FAME). Pre-reforming sulphur-free diesel at around 475C has been tested with a commercial nickel catalyst for 118 h without observing catalyst deactivation, at steam-to-carbon ratios as low as 2.6. Direct steam reforming at temperatures up to 800C has been tested with a commercial precious metal catalyst for a total of 1190 h with two catalyst batches at steam-to-carbon ratios as low as 2.5. Deactivation was neither observed with lower steam-to-carbon ratios nor for increasing sulphur concentration. The importance of good fuel evaporation and mixing for correct testing of catalysts is illustrated. Diesel containing biodiesel components resulted in poor spray quality, hence poor mixing and evaporation upstream, eventually causing decreasing catalyst performance. The feasibility of direct high temperature steam reforming of commercial low-sulphur diesel has been demonstrated.

Steam reforming of commercial ultra-low sulphur diesel

Science.gov (United States)

Boon, Jurriaan; van Dijk, Eric; de Munck, Sander; van den Brink, Ruud

Two main routes for small-scale diesel steam reforming exist: low-temperature pre-reforming followed by well-established methane steam reforming on the one hand and direct steam reforming on the other hand. Tests with commercial catalysts and commercially obtained diesel fuels are presented for both processes. The fuels contained up to 6.5 ppmw sulphur and up to 4.5 vol.% of biomass-derived fatty acid methyl ester (FAME). Pre-reforming sulphur-free diesel at around 475 °C has been tested with a commercial nickel catalyst for 118 h without observing catalyst deactivation, at steam-to-carbon ratios as low as 2.6. Direct steam reforming at temperatures up to 800 °C has been tested with a commercial precious metal catalyst for a total of 1190 h with two catalyst batches at steam-to-carbon ratios as low as 2.5. Deactivation was neither observed with lower steam-to-carbon ratios nor for increasing sulphur concentration. The importance of good fuel evaporation and mixing for correct testing of catalysts is illustrated. Diesel containing biodiesel components resulted in poor spray quality, hence poor mixing and evaporation upstream, eventually causing decreasing catalyst performance. The feasibility of direct high temperature steam reforming of commercial low-sulphur diesel has been demonstrated.

Extraction of niobium and tantalum with bis-2-ethylhexyl acetamide

International Nuclear Information System (INIS)

Ohmori, Hiroshi; Shibata, Junji; Sano, Makoto; Nishimura, Sanji

1986-01-01

Extraction of Nb and Ta from acid solutions with bis-2-ethylhexyl acetamide and stripping of these metals with sulphuric acid solutions were investigated. The organic phase was a binary solution of bis-2-ethylhexyl acetamide and xylene, while the aqueous phase was composed of hydrofluoric acid solution or hydrofluoric-sulphuric acid solution containing 3.5 - 13 kg/m 3 Nb and 5 - 10 kg/m 3 Ta. Sulphuric acid, hydrochloric acid and nitric acid were used as salting out agents to understand the effect on the extraction. Both metals were not sufficiently extracted from hydrofluoric acid solutions, whereas the extraction of both metals remarkably increased with an addition of sulphuric acid to the aqueous phase. The separation factor decreased with an increase in the concentration of hydrofluoric acid at the constant sulphuric acid concentration of 5.8N, and both metals were completely coextracted in the aqueous condition of 6N hydrofluoric acid and 8N sulphuric acid. The stripping occurred for both metals with a high efficiency, when water or dilute sulphuric acid solution was used as a stripping agent. The increase in sulphuric acid concentration caused less stripping of Ta, while the stripping of Nb was maintained at 80 % up to 7N sulphuric acid. The separation factor reached the maximum with the value of 116 in the use of 6.5N sulphuric acid. The extraction behavior of Fe(II), Fe(III), Sn(IV) and Mn(II) was also examined with the results that these metals were not extracted even to the extent of the lowest limit of atomic absorption spectrophotometer. Moreover, the comparison of this extractant with MIBK and TBP, which were in common use, was carried out. (author)

Use of Hg-Electroplated-Pt Ultramicroelectrode for Determining Elemental Sulphur in Naphtha Samples

Directory of Open Access Journals (Sweden)

Carlos Eduardo de Andrade

2012-01-01

Full Text Available This paper describes the applicability of a Hg-electroplated-Pt ultramicroelectrode in the quantification of elemental sulphur in naphtha samples by square-wave voltammetry. A reproducible deposition methodology was studied and is reported in this paper. This methodology is innovative and relies on the quality of the mercury stock solution to obtain reproducible surfaces required for the analytical methodology. All analyses were performed using a Hg-electroplated-Pt ultramicroelectrode (Hg-Pt UME due to the low sensibility of such devices to ohmic drops in resistive solutions. The responses of the peak areas in voltammetric experiments were linear in all of the range studied. The method developed here is accurate and reproducible, with a detection limit of 0.010 mg L−1 and a good recovery range for both standard solutions of elemental sulphur (85 to 99% and real naphtha sample (79%. These results attest to the potential for the application of this electroanalytical methodology in determining elemental sulphur in naphtha samples containing mercaptans and disulphides.

Selective environmental stress from sulphur emitted by continental flood basalt eruptions

Science.gov (United States)

Schmidt, Anja; Skeffington, Richard; Thordarson, Thorvaldur; Self, Stephen; Forster, Piers; Rap, Alexandru; Ridgwell, Andy; Fowler, David; Wilson, Marjorie; Mann, Graham; Wignall, Paul; Carslaw, Ken

2016-04-01

Several biotic crises during the past 300 million years have been linked to episodes of continental flood basalt volcanism, and in particular to the release of massive quantities of magmatic sulphur gas species. Flood basalt provinces were typically formed by numerous individual eruptions, each lasting years to decades. However, the environmental impact of these eruptions may have been limited by the occurrence of quiescent periods that lasted hundreds to thousands of years. Here we use a global aerosol model to quantify the sulphur-induced environmental effects of individual, decade-long flood basalt eruptions representative of the Columbia River Basalt Group, 16.5-14.5 million years ago, and the Deccan Traps, 65 million years ago. For a decade-long eruption of Deccan scale, we calculate a decadal-mean reduction in global surface temperature of 4.5 K, which would recover within 50 years after an eruption ceased unless climate feedbacks were very different in deep-time climates. Acid mists and fogs could have caused immediate damage to vegetation in some regions, but acid-sensitive land and marine ecosystems were well-buffered against volcanic sulphur deposition effects even during century-long eruptions. We conclude that magmatic sulphur from flood basalt eruptions would have caused a biotic crisis only if eruption frequencies and lava discharge rates had been high and sustained for several centuries at a time.

Determination of the optimum standardised ileal digestible sulphur amino acids to lysine ratio in weaned pigs challenged with enterotoxigenic Escherichia coli

DEFF Research Database (Denmark)

Capozzalo, M. M.; Resink, J. W.; Htoo, J. K.

2017-01-01

This experiment tested the hypothesis that pigs challenged with an enterotoxigenic strain of E. coli (ETEC) would require a higher sulphur amino acids (SAA) to Lys ratio (SAA:Lys). Pigs (n = 120) weighing 7.4 ± 0.52 kg (mean ± SD) and weaned at 27 d (Pietrain genotype, mixed sex) were stratified...

Inhibitory effect of non-ionic surfactants of the TRITON-X series on the corrosion of carbon steel in sulphuric acid

International Nuclear Information System (INIS)

Fuchs-Godec, R.

2007-01-01

The corrosion inhibition characteristics of non-ionic surfactants of the TRITON-X series, known as TRITON-X-100 and TRITON-X-405, on stainless steel (SS) type X4Cr13 in sulphuric acid were investigated by potentiodynamic polarisation measurements. It was found that these surfactants act as good inhibitors of the corrosion of stainless steel in 2 mol L -1 H 2 SO 4 solution, but the inhibition efficiency strongly depends on the electrode potential. The polarisation data showed that the non-ionic surfactants used in this study acted as mixed-type inhibitors and adsorb on the stainless steel surface, in agreement with the Flory-Huggins adsorption isotherm. Calculated ΔG ads values are -57.79 kJ mol -1 for TRITON-X-100, and -87.5 kJ mol -1 for TRITON-X-405. From the molecular structure it can be supposed that these surfactants adsorb on the metal surface through two lone pairs of electrons on the oxygen atoms of the hydrophilic head group, suggesting a chemisorption mechanism

Strange and non-strange baryon and antibaryon production in sulphur-tungsten and sulphur-sulphur interactions at 200 A Gev/c

Energy Technology Data Exchange (ETDEWEB)

Holme, A.K.

1995-11-01

The author has studied production of strange and multistrange baryons and antibaryons in central sulphur-tungsten, sulphur-sulphur, and lead-lead interactions at relativistic energies. The spectra of strange baryons and antibaryons provide information about the dynamics of hadronic matter under the extreme conditions realised in these collisions. The particle ratios allow the degree and the nature of the flavour equilibrium to be studied, while the transverse mass distributions provide independent information of the temperatures achieved. 143 refs.

Strange and non-strange baryon and antibaryon production in sulphur-tungsten and sulphur-sulphur interactions at 200 A Gev/c

International Nuclear Information System (INIS)

Holme, A.K.

1995-11-01

The author has studied production of strange and multistrange baryons and antibaryons in central sulphur-tungsten, sulphur-sulphur, and lead-lead interactions at relativistic energies. The spectra of strange baryons and antibaryons provide information about the dynamics of hadronic matter under the extreme conditions realised in these collisions. The particle ratios allow the degree and the nature of the flavour equilibrium to be studied, while the transverse mass distributions provide independent information of the temperatures achieved. 143 refs

Empirical modeling of solvent extraction of uranium from sulphuric acid medium using PC-88A and TOPO as extractants

International Nuclear Information System (INIS)

Biswas, S.; Roy, S.B.; Pathak, P.N.; Manchanda, V.K.; Singh, D.K.

2011-01-01

Extraction behavior of uranium (VI) from sulphuric acid medium using PC-88A (H 2 A 2 , dimer form) and a mixture of PC-88A + TOPO in n-dodecane has been investigated. The extraction data have been used to develop a mathematical model correlating percentage extraction (%E) with PC-88A and TOPO concentration. It can be used to predict the steady-state concentrations of metal ion under the conditions of the present work. (author)

Evaluation of Plants and Weeds Extract on the Corrosion Inhibition of Mild Steel in Sulphuric Acid

Directory of Open Access Journals (Sweden)

Abida Begum

2011-01-01

Full Text Available Experiments were performed in order to determine the inhibitive effects of extracts of plants and weeds namely Parthenium hysterophorus, Dathura stromonium, Azadirachta indica, Helianthus annuus leaves extract for mild steel in sulphuric acid by using weight loss and thermometric technique. Results demonstrated that, all the experimental inhibitors show an adsorption on steel surface according to Langmuir’s isotherm. The inhibition efficiency increased with increase in the concentration of all tested inhibitors to attain a maximum value at 1.0%. Free energy values for adsorption process show that the process is spontaneous. The kinetic treatment of the results shows first order kinetics.

Use of stable sulphur isotopes to monitor directly the behaviour of sulphur in coal during thermal desulphurization

Science.gov (United States)

Liu, Chao-Li; Hackley, Keith C.; Coleman, D.D.

1987-01-01

A method has been developed using stable sulphur isotope analyses to monitor the behaviour of sulphur forms in a coal during thermal desulphurization. In this method, the natural stable isotopic composition of the pyritic and organic sulphur in coal is used as a tracer to follow their mobility during the desulphurization process. This tracer method is based on the fact that the isotopic compositions of pyritic and organic sulphur are significantly different in some coals. Isotopic results of pyrolysis experiments at temperatures ranging from 350 to 750 ??C indicate that the sulphur released with the volatiles is predominantly organic sulphur. The pyritic sulphur is evolved in significant quantities only when pyrolysis temperatures exceed 500 ??C. The presence of pyrite seems to have no effect on the amount of organic sulphur evolved during pyrolysis. The chemical and isotopic mass balances achieved from three different samples of the Herrin (No. 6) coal of the Illinois Basin demonstrate that this stable isotope tracer method is quantitative. The main disadvantage of this tracing technique is that not all coals contain isotopically distinct organic and pyritic sulphur. ?? 1987.

Determination of chloride and sulphur in sodium by ion chromatography and its application to PFBR sodium samples

International Nuclear Information System (INIS)

Vijayalakshmi, S.; Ushalakshmi, K.

2011-01-01

Analytical method using ion chromatography was developed for the determination of chloride and sulphur in sodium. In this method, sodium was dissolved in water and various sulphur species present in the sample was oxidized to sulphate using hydrogen peroxide. Carbon dioxide gas was passed through the solution to convert sodium hydroxide to carbonate solution. The resulting sample solution was analysed using suppressed Ion chromatography employing carbonate eluent. This method was applied to the analysis of sodium samples procured for prototype fast breeder reactor. (author)

Effect of NPK fertilization and elemental sulphur on growth and yield of lowbush blueberry

Directory of Open Access Journals (Sweden)

M. STARAST

2008-12-01

Full Text Available The aim of the research was to determine the effect of fertilizers on the pH of former arable soils and on the growth and the yield of the lowbush blueberry (Vaccinium angustifolium Ait.. Lowbush blueberry fertilization experiments were established in 1999 at two locations – at Kärla, Saaremaa, West Estonia and at Vasula, Tartu County, South Estonia. Experimental sites were situated on different soils: soil pHKCl at Kärla was 5.5 and at Vasula 6.2. Elemental sulphur and acidifying fertilizers (ammonium sulfate, potassium sulfate and superphosphate were used in both plantations. Fertilizers were applied based on nutrient in the soil and sulphur was applied at 100 g m–2. Plant growth was recorded in 2001, 2002 and 2003. A positive influence of NPK fertilization on yield was found in both Kärla and Vasula, and yield were 336 g and 41 g higher compared to the control, respectively. The vegetative growth and yield of blueberry depended significantly on soil pH. Elemental sulphur increased soil acidity and on loamy sand soil did not increase plant productivity. The sulphur effect on soil pH began to decrease three years after application. Sulphur can be recommended to increase soil acidity in nutrient-rich soil but, not nutrient poor soil with light texture, where only NPK fertilizers were effective.;

Acid-digestion plant for plutonium-contaminated waste at the Swiss Federal Institute for Reactor Research

International Nuclear Information System (INIS)

Guentensperger, M.A.

1981-01-01

At the Swiss Federal Institute for Reactor Research (EIR), plutonium-contaminated material (PCM) is accumulated in the ''hot-laboratory''. Acid digestion has been chosen for conditioning the combustible PCM at EIR. The acid-digestion process is based on the carbonization and oxidative decomposition of the PCM by means of concentrated sulphuric and nitric acids at temperatures around 250 0 C. The design study for the acid-digestion plant (ADA) for EIR has almost been completed, and the detailed design has begun. The shredded waste will be fed batchwise on to the surface of hot sulphuric acid in the digester tray where carbonization occurs. The oxidation of the carbonized particles to gaseous products occurs in the heater vessel where nitric acid is added to accelerate the reaction. The inorganic residues of the digested PCM accumulate in the heater vessel as suspended particles. Periodically the acid is drained and the solid residue is separated. The gaseous effluents pass through a battery of oxidation/absorption columns where SO 2 and NOsub(x) are oxidized to sulphuric and nitric acids, respectively. These acids are almost entirely absorbed in the washing solution which is fed continuously to the acid-rectification system. The separated and reconcentrated acids are reused. For safety reasons the ADA will be semi-automatic; the principal alarms are transmitted to a control centre. Automatic shut-down is achieved by cutting off the heater current and adding cold sulphuric acid. (author)

Acid leaching of coal: to produce clean fuels from Turkish lignite

Energy Technology Data Exchange (ETDEWEB)

Seferinoglu, Meryem [Mineral Research and Exploration Directorate (Turkey)], email: meryem_seferinoglu66@yahoo.com; Duzenli, Derya [Ankara Central Laboratory (Turkey)

2011-07-01

With the increasing concerns about the environment, energy producers and governments are looking at developing clean energy sources. However, Turkey has limited clean energy resources and is using low grade coal which has high sulphur content as an alternative energy source. The aim of this paper is to study the possibility of generating clean fuel from Edirne Lignite and to get a better understanding of chemical mechanisms involved in coal leaching with hydrofluoric acid (HF) solutions. Leaching was conducted on Edirne Lignite with HF solution at ambient temperature and the effects of parameters such as reaction time and concentration of acid solutions on the process were evaluated. The optimum conditions were found and it was shown that ash levels can be reduced from 28.9% to 10.5% and the calorific value increased by 500kcal/kg with the HF leaching method. This study demonstrated that the production of clean fuel from high sulphur lignite is possible.

Removal of sulfamic acid from plutonium sulfamate--sulfamic acid solution

International Nuclear Information System (INIS)

Gray, L.W.

1978-10-01

Plutonium metal can be readily dissolved in aqueous solutions of sulfamic acid. When the plutonium sulfamate--sulfamic acid solutions are added to normal purex process streams, the sulfamate ion is oxidized by addition of sodium nitrite. This generates sodium sulfate which must be stored as radioactive waste. When recovery of ingrown 241 Am or storage of the dissolved plutonium must be considered, the sulfamate ion poses major and undesirable precipitation problems in the process streams. The present studies show that 40 to 80% of the sulfamate present in the dissolver solutions can be removed by precipitation as sulfamic acid by the addition of concentrated nitric acid. Addition of 64% nitric acid allows precipitation of 40 to 50% of the sulfamate; addition of 72% nitric acid allows precipitation of 50 to 60% of the sulfamate. If the solutions are chilled, additional sulfamic acid will precipitate. If the solutions are chilled to -10 0 C, about 70 to 80% of the orginal sulfamic acid in the dissolver will precipitate. A single, low-volume wash of the sulfamic acid crystals with concentrated nitric acid will decontaminate the crystals to a plutonium content of 5 dis/(min-gram)

Extraction of some acids using aliphatic amines

International Nuclear Information System (INIS)

Matutano, L.

1964-06-01

Hydrochloric, nitric, sulphuric, perchloric, phosphoric, acetic and formic acids in aqueous solution (0.05 to 10 M) are extracted by amberlite LA2 and trilaurylamine in solution, 5 per cent by volume, in kerosene and xylene respectively. The extraction process consists of: neutralization of the amine salt; a 'molecular extraction', i.e. an extraction using an excess of acid with respect to the stoichiometry of the amine salt. According to the behaviour of the acid during the extraction, three groups may be distinguished: completely dissociated acids, carboxylic acids, phosphoric acid. This classification is also valid for the extraction of the water which occurs simultaneously with that of the acid. An extraction mechanism is put forward for formic acid and the formation constant of its amine salt is calculated. (author) [fr

Acetic acid extraction from aqueous solutions using fatty acids

NARCIS (Netherlands)

IJmker, H.M.; Gramblicka, M.; Kersten, Sascha R.A.; van der Ham, Aloysius G.J.; Schuur, Boelo

2014-01-01

A major challenge for production of acetic acid via bio-based routes is cost-effective concentration and purification of the acetic acid from the aqueous solutions, for which liquid–liquid extraction is a possible method. A main challenge in extraction of acetic acid from dilute aqueous solutions is

Silver-zinc electrodeposition from a thiourea solution with added EDTA or HEDTA

International Nuclear Information System (INIS)

Oliveira, G.M. de; Carlos, I.A.

2009-01-01

This paper shows the study of silver-zinc electrodeposition from a thiourea solution with added (ethylenedinitrilo)tetraacetic acid (EDTA), disodium salt and N-(2-hydroxyethyl)ethylenediaminetriacetic acid (HEDTA), trisodium salt. Voltammetric results indicated that silver-zinc alloy can be obtained applying overpotential higher than 0.495 V, in Tu solution containing 1.0 x 10 -1 mol L -1 Zn(NO 3 ) 2 + 2.5 x 10 -2 mol L -1 AgNO 3 . This was due to silver(I) ion complexation with thiourea, which shifted the silver deposition potential to more negative value and due to silver-zinc alloy deposition, which occurred at potentials more positive than the potential to zinc deposition alone. EDTA or HEDTA did not significantly affect the silver and zinc deposition potentials, but decreased the current density for silver-zinc deposition. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analyses of the silver-zinc deposits showed that the morphology and composition changed as a function of the conditions of deposition, viz, deposition potential (E d ), deposition charge density (q d ) and solution composition (silver, EDTA and HEDTA concentrations). EDS analysis of the deposits showed sulphur (S) incorporated into the silver-zinc deposit, while SEM images showed that this sulphur content seemed to improve the silver-zinc morphology, as did the presence of EDTA and HEDTA in the solution, which enhanced the sulphur incorporation into the silver-zinc deposit. X-ray diffraction (XRD) analysis of the silver-zinc deposit showed that it was amorphous, irrespective of its composition and morphology

Performance evaluation of high-sulphur coal-fired USC plant integrated with SNOX and CO2 capture sections

International Nuclear Information System (INIS)

Cau, Giorgio; Tola, Vittorio; Bassano, Claudia

2015-01-01

In recent years coal-fired power plants have increased their role in the global energy scenario thanks to reliability, security of fuel supply and lower cost of fuel and electricity. In this framework global warming issues require a sustainable use of coal and great efforts for greenhouse gases reduction, addressing research and development projects towards more efficient solutions in terms of efficiency and environmental impact. With this aim in this paper a performance assessment of an Ultra Super Critical (USC) steam plant integrated with a CO 2 removal section was carried out. The study is based on simulation models specifically developed through Aspen-Plus and Gate-Cycle software platforms. Performance was assessed referring to typical USC commercial size plants (400–600 MW), fuelled by a mix of a low-sulphur coal and a Sardinian (Sulcis) high-sulphur coal. The USC plant, based on a reheated and regenerative Rankine cycle, is integrated with an SNOX section, with integrated DeNO x and DeSO x processes, and a low temperature CO 2 capture section. The SNOX technology shows several advantages in comparison to conventional de-nitrification and de-sulphuration systems. In particular it is capable to remove both nitrogen and sulphur oxides, requiring less energy absorption compared to traditional FGD systems, allowing a further preheating of the combustion air and without producing process waste. Besides the SNOX releases a commercial product as the sulphuric acid (H 2 SO 4 ) and operational costs are reduced when sulphur content in the coal increases. The CO 2 capture system was based on a chemical absorption process. A conventional system based on an amine (monoethanolamine, MEA) aqueous solution was considered. In order to match high pressure and purity CO 2 transportation requirements, the CO 2 removal section is also integrated with a conditioning and compression section. A performance assessment of the USC plant was carried out varying the high-sulphur coal

Effect of aliphatic, monocarboxylic, dicarboxylic, heterocyclic and sulphur-containing amino acids on Leishmania spp. chemotaxis.

Science.gov (United States)

Diaz, E; Zacarias, A K; Pérez, S; Vanegas, O; Köhidai, L; Padrón-Nieves, M; Ponte-Sucre, A

2015-11-01

In the sand-fly mid gut, Leishmania promastigotes are exposed to acute changes in nutrients, e.g. amino acids (AAs). These metabolites are the main energy sources for the parasite, crucial for its differentiation and motility. We analysed the migratory behaviour and morphological changes produced by aliphatic, monocarboxylic, dicarboxylic, heterocyclic and sulphur-containing AAs in Leishmania amazonensis and Leishmania braziliensis and demonstrated that L-methionine (10-12 m), L-tryptophan (10-11 m), L-glutamine and L-glutamic acid (10-6 m), induced positive chemotactic responses, while L-alanine (10-7 m), L-methionine (10-11 and 10-7 m), L-tryptophan (10-11 m), L-glutamine (10-12 m) and L-glutamic acid (10-9 m) induced negative chemotactic responses. L-proline and L-cysteine did not change the migratory potential of Leishmania. The flagellum length of L. braziliensis, but not of L. amazonensis, decreased when incubated in hyperosmotic conditions. However, chemo-repellent concentrations of L-alanine (Hypo-/hyper-osmotic conditions) and L-glutamic acid (hypo-osmotic conditions) decreased L. braziliensis flagellum length and L-methionine (10-11 m, hypo-/hyper-osmotic conditions) decreased L. amazonensis flagellum length. This chemotactic responsiveness suggests that Leishmania discriminate between slight concentration differences of small and structurally closely related molecules and indicates that besides their metabolic effects, AAs play key roles linked to sensory mechanisms that might determine the parasite's behaviour.

Sulphur in liquid fuels 2002

Energy Technology Data Exchange (ETDEWEB)

Guthrie, J. [Environment Canada, Gatineau, PQ (Canada). Fuels Div., Oil, Gas and Energy Branch ; Sabourin, R. [Carleton Univ., Ottawa, ON (Canada)

2003-08-01

Environment Canada has developed new regulations for sulphur content in fuels in an effort to align with requirements recently passed by the U.S. Environmental Protection Agency. This report summarizes data regarding sulphur content in liquid fuels for the year 2002. The requirements of the Sulphur in Gasoline Regulation came into effect in 2002, limiting the average sulphur content of gasoline to 150 mg/kg. In January 2005, a 30 mg/kg average limit will come into effect. Also, in July 2002, the Sulphur in Diesel Fuel Regulation stipulated a maximum limit of 500 mg/kg for on-road diesel fuel. The new regulation continues this limit until mid-2006 at which time a 15 mg/kg limit will come into effect for on-road diesel fuel. Nationally, the average sulphur content in gasoline in 2002 was 246 mg/kg, which was 14.3 per cent lower than in 2001. The data covers the period from January 1 to December 31, 2002 and was obtained from petroleum refineries and importing companies that are required to submit quarterly information to the regional office of Environment Canada. Failure to comply results in penalties. The report includes data for aviation turbo fuel, motor gasoline, aviation gasoline, kerosene oil, low-sulphur diesel fuel, diesel fuel, light fuel oil, and heavy fuel oil. 16 tabs., 17 figs., 7 appendices.

Effect of elemental sulphur and compost on pH, electrical ...

African Journals Online (AJOL)

Safir

2012-01-19

Jan 19, 2012 ... 42/34. T.N.V. 4.5. P (mg kg-1) ... and extracted with 2.0 M HCl) were measured with similar methods ... react with carbonate in calcareous soil and neutralize it. Neilson ... oxidation in soil, the sulphuric acid formed reacted with.

Corrosion behaviour of WC-VC-Co hardmetals in acidic media

CSIR Research Space (South Africa)

Konadu, DS

2010-09-01

Full Text Available The effect of increasing vanadium carbide (VC) content on the corrosion behaviour of tungsten carbide – 10 wt% cobalt hard metals was investigated in 1 M hydrochloric (HCl), and sulphuric (H2SO4) acids solutions. Increasing VC content makes the open...

Tracer study on sulphur use efficiency in potato-barley sequence on acid soil of Shimla

International Nuclear Information System (INIS)

Sud, K.C.; Sharma, R.C.; Sharma, N.K.

1999-01-01

Controlled studies were conducted on acidic soil of Fagu (Shimla) to study the efficiency of labelled ammonium sulphate as effected by farmyard manure (FYM) on potato (Solanum tuberosum L.) and its residual effect on succeeding barley (Hordeum vulgare L.). The direct and residual effects of FYM and sulphur on dry matter yield and S concentration in potato and barley plants were significant. Applied FYM had a positive effect on radioassay values i.e. % Sdff and % S utilization by potato from labelled S carrier, whereas, the residual effect of applied S on barley was more than its direct effect on potato. Results indicate that combined application of S and FYM resulted in 3.4 per cent more S contribution to barley crop and was reflected in % S utilization values. (author)

Extraction of plutonium from phosphate containing nitric acid solutions using DHDECMP as extractant (Preprint no. SSC-03)

International Nuclear Information System (INIS)

Sagar, V.B.; Pawar, S.M.; Joshi, A.R.; Kasar, U.M.; Sivaramkrishnan, C.K.

1991-01-01

Distribution data for the extraction of Pu(IV) by DHDECMP (Di-hexyl, N-N-diethylcarbamoylmethylphosphonate) in xylene from aqueous nitric acid and its mixtures with sulphuric acid and phosphoric acid were obtained to explore the feasibility of recovery of Pu(IV) from analytical waste generated in the laboratory. Based on the data obtained, conditions for recovery of plutonium are suggested. (author). 3 refs., 3 tabs

A new biological method for preparing certain sulphurated substances labelled with S35

International Nuclear Information System (INIS)

Chapeville, F.; Maier-Huser, H.; Fromageot, P.

1962-01-01

Previous investigations have shown that the yolk-sac of embryonic bird's eggs can be used to produce the following reactions: (a) reduction of sulphate to sulphite; (b) fixation of the sulphite on the carbon chain produced by the desulf-hydration of l-cysteine, with formation of l-cysteic acid; (c) decarboxylation of the l-cysteine acid into taurine. The enzymatic system which causes reaction (b) has been purified. It also acts as a catalyst in the sulphur-exchange between the cysteine and the mineral sulphide. The authors have utilized these data in preparing sulphurated substances labelled with S 35 : taurine S 35 , l-cysteine S 35 and l-cysteic acid S 35 . For each of the three, they discuss the chemical reactions involved, the methods of preparation, the experimental conditions of extraction and purity-control, together with the yields and specific activities obtained. (authors) [fr

Polarographic behaviour and determination of uranium(VI) in alcoholic solutions from organic extraction phases

International Nuclear Information System (INIS)

Degueldre, C.; Taibi, K.

1996-01-01

The determination of U(VI) in organic extraction phases: hydrocarbon-diethyl-2-hexyl phosphoric acid-trioctylphosphine oxide and hydrocarbon-tri-n-octylamine, diluted by an alcohol has been studied by direct current polarography, as well as by differential pulse polarography (DPP). In order to optimise the analytical procedure, miscibility and conductivity studies of the mixtures hydrocarbon-alcohol (ethanol, n- and isopropanol and n- and isobutanol) were made after addition of sulphuric acid as a supporting electrolyte. In the solutions of sulphuric acid in the alcohol-extractant-hydrocarbon phases, U(VI) gives rise to well defined polarograms. Its electroreduction involves a single electron step in all cases. The DPP peak height is proportional to the U(VI) concentration between 2x10 -6 and 2x10 -3 M, and the 3σ detection limit is ca. 10 -6 M

Removing sulphur oxides from a fluid stream

Science.gov (United States)

Katz, Torsten; Riemann, Christian; Bartling, Karsten; Rigby, Sean Taylor; Coleman, Luke James Ivor; Lail, Marty Alan

2014-04-08

A process for removing sulphur oxides from a fluid stream, such as flue gas, comprising: providing a non-aqueous absorption liquid containing at least one hydrophobic amine, the liquid being incompletely miscible with water; treating the fluid stream in an absorption zone with the non-aqueous absorption liquid to transfer at least part of the sulphur oxides into the non-aqueous absorption liquid and to form a sulphur oxide-hydrophobic amine-complex; causing the non-aqueous absorption liquid to be in liquid-liquid contact with an aqueous liquid whereby at least part of the sulphur oxide-hydrophobic amine-complex is hydrolyzed to release the hydrophobic amine and sulphurous hydrolysis products, and at least part of the sulphurous hydrolysis products is transferred into the aqueous liquid; separating the aqueous liquid from the non-aqueous absorption liquid. The process mitigates absorbent degradation problems caused by sulphur dioxide and oxygen in flue gas.

On the effects of organic matter and sulphur-containing compounds on the CCN activation of combustion particles

Directory of Open Access Journals (Sweden)

A. Petzold

2005-01-01

Full Text Available The European PartEmis project (Measurement and prediction of emissions of aerosols and gaseous precursors from gas turbine engines was focussed on the characterisation and quantification of exhaust emissions from a gas turbine engine. The combustion aerosol characterisation included on-line measurements of mass and number concentration, size distribution, mixing state, thermal stability of internally mixed particles, hygroscopicity, cloud condensation nuclei (CCN activation potential, and off-line analysis of chemical composition. Based on this extensive data set, the role of sulphuric acid coating and of the organic fraction of the combustion particles for the CCN activation was investigated. Modelling of CCN activation was conducted using microphysical and chemical properties obtained from the measurements as input data. Coating the combustion particles with water-soluble sulphuric acid, increases the potential CCN activation, or lowers the activation diameter, respectively. The adaptation of a Köhler model to the experimental data yielded coatings from 0.1 to 3 vol-% of water-soluble matter, which corresponds to an increase in the fraction of CCN-activated combustion particles from ≤10−4 to ≌10−2 at a water vapour saturation ratio Sw=1.006. Additional particle coating by coagulation of combustion particles and aqueous sulphuric acid particles formed by nucleation further reduces the CCN activation diameter. In contrast, particles containing a large fraction of non-volatile organic compounds grow significantly less at high relative humidity than particles with a lower content of non-volatile OC. The resulting reduction in the potential CCN activation with an increasing fraction of non-volatile OC becomes visible as a trend in the experimental data. While a coating of water-soluble sulphuric acid increases the potential CCN activation, or lowers the activation diameter, respectively, the non-volatile organic compounds, mainly found at

Pyroclastic sulphur eruption at Poas Volcano, Costa Rica

Energy Technology Data Exchange (ETDEWEB)

Francis, P.W.; Thorpe, R.S.; Brown, G.C.; Glasscock, J.

1980-01-01

The recent Voyager missions to Jupiter have highlighted the role of sulphur in volcanic processes on io. Although fumarolic sulphur and SO/sub 2/ gas are almost universal in terrestrial active volcanoes, and rare instances of sulphur lava flows have been reported, sulphur in a pyroclastic form has only been described from Poas Volcano, Costa Rica. Here we amplify the original descriptions by Bennett and Raccichini and describe a recent eruption of pyroclastic sulphur scoria and ejected blocks that are characterised by miniature sulphur stalactites and stalagmites.

Changes in the content of water-soluble sulphur in the soil after an application of straw and elemental sulphur

Directory of Open Access Journals (Sweden)

Pavel Ryant

2007-01-01

Full Text Available The changes in the content of water-soluble sulphur in the soil after the application of straw and elemental sulphur (ES were explored in a 2-year vegetation pot experiment. The following variants were included in the experiment: 1 unfertilised control; 2 wheat straw; 3 rape straw; 4 ES; 5 wheat straw + ES; 6 rape straw + ES. The two types of straw were applied in a dose of 32 g of dry matter and elemental sulphur was applied in a dose of 0.42 g per pot, i.e. 6 kg of soil. The unsatisfactory C:N ratio in the straw was optimised to 25:1 by adding nitrogen in urea. Soil samples were taken prior to sowing of the model plant (spring wheat in 2005 and white mustard in 2006 and then in regular monthly intervals until harvesting (5 times a year. The content of water-soluble sulphur in the soil was evaluated by multifactorial analysis of variance monitoring the effect of the crop, date of soil sampling, application of straw and elemental sulphur.The contents of water-soluble sulphur differed statistically significantly (P > 0.999 when growing the individual model plants. When growing white mustard in 2006 the amount of available sulphur was by 1/5 higher and could have been partly affected by the warm year 2006, as compared to 2005 when spring wheat was grown. Significant differences (P > 0.999 were also discovered among the dates of soil sampling; higher values were detected before the sowing of model plants, i.e. after incubation in the winter, during vegetation the content of water-soluble sulphur decreased and sulphur showed the significantly highest values at the harvest of model plants. When wheat straw was applied the sulphur content did not increase and this may be associated with the wide C:S ratio, whereas after the application of rape straw the content of water-soluble sulphur increased by one third more than in the unfertilised control. The application of elemental sulphur also significantly increased the amount of water-soluble sulphur in

Determination of the optimum standardised ileal digestible sulphur amino acids to lysine ratio in weaned pigs challenged with enterotoxigenic Escherichia coli

DEFF Research Database (Denmark)

Capozzalo, M. M.; Resink, J. W.; Htoo, J. K.

2017-01-01

This experiment tested the hypothesis that pigs challenged with an enterotoxigenic strain of E. coli (ETEC) would require a higher sulphur amino acids (SAA) to Lys ratio (SAA:Lys). Pigs (n = 120) weighing 7.4 ± 0.52 kg (mean ± SD) and weaned at 27 d (Pietrain genotype, mixed sex) were stratified...... into 1 of 6 treatments based on weaning weight, sex and genotype for the F4 fimbria receptor (n = 20). Five diets were formulated with increasing ratios of standardised ileal digestible (SID) sulphurSAA:Lys. Pigs were housed in pens of 4 during an adaptation period of 6 d after which time pigs were...... housed individually. Pigs fed different SID SAA:Lys levels were infected with ETEC (5 mL, 1.13 × 108 CFU/mL, serotype O149:K91:K88) on d 8, 9, and 10 after weaning. The sixth diet, which contained 0.55 SID SAA:Lys and corresponded to current NRC recommendations, was allocated to 2 groups of pigs either...

Yeast strains role on the sulphur dioxyde combinations of wines obtained from noble rot and raisining grapes

Directory of Open Access Journals (Sweden)

Isabelle Masneuf-Pomarède

2000-03-01

Full Text Available The influence of four industrial and indigenous yeast strains on the sulphur dioxide combinations of wines obtained from noble rot and raisining grapes is studied in different growth of the Sauternes area and one growth in the Jurançon area. The analysis of ketonic compounds (pyruvic acid and 2-oxo-glutaric acid, acetaldehyde and PC50 on the wines clearly showed significant statistical difference between the yeast strains for the sulphur dioxide combination. By adding the same dosage of sulphiting, the free SO2 levels are variable depending on the yeast strain used. One strain (Zymaflore ST, isolated from a spontaneous fermentation of a botrytised must, giving wines with low PC50 values, is well adapted for the noble rot must vinification. The choice of the yeast strain is a parameter of importance to limit the sulphur dioxide amount in the wines.

Sulphur capture by co-firing sulphur containing fuels with biomass fuels - optimization

International Nuclear Information System (INIS)

Nordin, A.

1992-12-01

Previous results concerning co-firing of high sulphur fuels with biomass fuels have shown that a significant part of the sulphur can be absorbed in the ash by formation of harmless sulphates. The aim of this work has been to (i) determine the maximum reduction that can be obtained in a bench scaled fluidized bed (5 kW); (ii) determine which operating conditions will give maximum reduction; (iii) point out the importance and applicability of experimental designs and multivariate methods when optimizing combustion processes; (iv) determine if the degree of sulphur capture can be correlated to the degree of slagging, fouling or bed sintering; and (v) determine if further studies are desired. The following are some of the more important results obtained: - By co-firing peat with biomass, a total sulphur retention of 70 % can be obtained. By co-firing coal with energy-grass, the total SO 2 emissions can be reduced by 90 %. - Fuel feeding rate, amount of combustion air and the primary air ratio were the most important operating parameters for the reduction. Bed temperature and oxygen level seem to be the crucial physical parameters. - The NO emissions also decreased by the sulphur reducing measures. The CO emissions were relatively high (130 mg/MJ) compared to large scale facilities due to the small reactor and the small fluctuations in the fuel feeding rate. The SO 2 emissions could however be reduced without any increase in CO emissions. - When the reactor was fired with a grass, the bed sintered at a low temperature ( 2 SO 4 and KCl are formed no sintering problems were observed. (27 refs., 41 figs., 9 tabs., 3 appendices)

Environmental aspects of sulphuric acid in situ leach uranium mining in the permafrost zone (Vitim District, Russian Federation)

International Nuclear Information System (INIS)

Fazlullin, M.I.; Boitsov, A.V.

2002-01-01

Currently in situ leaching pilot tests are in progress at the Khiagda deposit, Vitim District, Russian Federation. The deposit is of the sandstone basal channel type, or paleovalley type in the Russian classification. It contains about 15 000 mt U at an ore grade averaging 0.05% U. Mineralization occurs in permeable unconsolidated Neogene fluvial sediments located below the permafrost which extends to 100 m deep. The basement rock is Paleozoic granite. Neogene-Quaternary basalts overlap the ore hosting sediments. The thickness of the ore host horizon varies from a few meters to 120 m. The depth of mineralization averages 170 m. Ore bodies are of lens and strataform shape. The following types of underground waters have been identified: groundwaters of the near surface or active layer, the aquifer in the Neogene volcanics, the ore host aquifer of the Neogene permeable sediments and fault related waters. The permeability in the ore bearing horizon varies from 0.1 to 20 m/day (averages 2 to 3 m/day). The waters of the productive aquifer are not suitable for industrial nor potable water supply due to their initial chemical composition. The ore host horizons occur between two impermeable horizons, which confine leaching solutions. Using sulphuric acid solutions as leaching reagent decreases the pH and increases Total Dissolved Solids (TDS) of the groundwaters within the leaching area due to concentration of sulphate-ion and other dissolved components. Principal components contaminating the underground waters are sulphates of aluminium, manganese, nickel and chrome. Their content during leaching significantly exceeds initial values. The available information on residual acid migration with the ground water shows that the concentration of contaminants significantly decreases away from the leaching contour. This occurs due to precipitation of contaminants during migration of the underground water from ISL sites. The external contour of the contamination aureole is defined

CLINSULF sub-dew-point process for sulphur recovery

Energy Technology Data Exchange (ETDEWEB)

Heisel, M.; Marold, F.

1988-01-01

In a 2-reactor system, the CLINSULF process allows very high sulphur recovery rates. When operated at 100/sup 0/C at the outlet, i.e. below the sulphur solidification point, a sulphur recovery rate of more than 99.2% was achieved in a 2-reactor series. Assuming a 70% sulphur recovery in an upstream Claus furnace plus sulphur condenser, an overall sulphur recovery of more than 99.8% results for the 2-reactor system. This is approximately 2% higher than in conventional Claus plus SDP units, which mostly consist of 4 reactors or more. This means the the CLINSULF SSP process promises to be an improvement both in respect of efficiency and low investment cost.

Design and modeling of an advanced marine machinery system including waste heat recovery and removal of sulphur oxides

DEFF Research Database (Denmark)

Frimann Nielsen, Rasmus; Haglind, Fredrik; Larsen, Ulrik

2013-01-01

-stroke diesel engine and a conventional waste heat recovery system. The results suggest that an organic Rankine cycle placed after the conventional waste heat recovery system is able to extract the sulphuric acid from the exhaust gas, while at the same time increase power generation from waste heat by 32...... consists of a two-stroke diesel engine, the wet sulphuric process for sulphur removal and an advanced waste heat recovery system including a conventional steam Rankine cycle and an organic Rankine cycle. The results are compared with those of a state-of-the-art machinery system featuring a two...

Quantification of chemical sulphur species in bulk soil and organic sulphur fractions by S K-edge Xanes spectroscopy

DEFF Research Database (Denmark)

Boye, K; Almkvist, G; Nilsson, S I

2011-01-01

residue (CR) incorporation and farmyard manure (FYM) application, with equal applications of mineral nutrients were included in the study. In the new data treatment method, internally calibrated spectra of dilute solutions (30 mm) of model compounds were used to fit the sample spectra. This greatly...... the opposite trend was observed. Sulphur XANES spectroscopy of acetylacetone extracts of physically protected and unprotected organic S in two of the soils revealed that physical protection was not related to S speciation; however, intermediate forms of oxidized S species appeared to accumulate in the residual...

Sulphurous Mineral Waters: New Applications for Health

Directory of Open Access Journals (Sweden)

Jose Manuel Carbajo

2017-01-01

Full Text Available Sulphurous mineral waters have been traditionally used in medical hydrology as treatment for skin, respiratory, and musculoskeletal disorders. However, driven by recent intense research efforts, topical treatments are starting to show benefits for pulmonary hypertension, arterial hypertension, atherosclerosis, ischemia-reperfusion injury, heart failure, peptic ulcer, and acute and chronic inflammatory diseases. The beneficial effects of sulphurous mineral waters, sulphurous mud, or peloids made from sulphurous mineral water have been attributed to the presence of sulphur mainly in the form of hydrogen sulphide. This form is largely available in conditions of low pH when oxygen concentrations are also low. In the organism, small amounts of hydrogen sulphide are produced by some cells where they have numerous biological signalling functions. While high levels of hydrogen sulphide are extremely toxic, enzymes in the body are capable of detoxifying it by oxidation to harmless sulphate. Hence, low levels of hydrogen sulphide may be tolerated indefinitely. In this paper, we review the chemistry and actions of hydrogen sulphide in sulphurous mineral waters and its natural role in body physiology. This is followed by an update of available data on the impacts of exogenous hydrogen sulphide on the skin and internal cells and organs including new therapeutic possibilities of sulphurous mineral waters and their peloids.

Sulphur removal in IGCC projects

Energy Technology Data Exchange (ETDEWEB)

Cross, F. (Parsons (United Kingdom))

1998-01-01

The technology for recovering elemental sulphur from H[sub 2]S bearing gases is well established. The modified Claus Process is the principal work-horse in sulphur recovery and can customarily achieve conversion efficiencies of 95% or better. Nowadays, such a level of recovery is no longer sufficient in most instances and sulphur recovery facility must then include some form of enhanced recovery, usually by treating the Claus tail gas. A number of processes have been introduced to enable the overall recovery to be increased. Recoveries in excess of 99% are both feasible and economic. Use of oxygen in place has become very popular in cases where oxygen is available cheaply or where capacity increases are designed. Most IGCC projects needing an air separation plant would automatically benefit from extending the use of oxygen to the sulphur recovery plant. The most popular route to minimising sulphur emissions in the context of IGCC projects has involved an oxygen based Claus plant followed by tail gas hydrogenation, hydrogen sulphide recovery and its recycle to the Claus section. The recovery of H[sub 2]S from the Claus tail gas can be integrated with the main gas treating system in the gasification plant. The cost advantage of doing so is significant. Parsons has been involved with the technology since 1949 and has been responsible for developments such as the ammonia burning Claus and jointly with Unocal, the BSRP tail gas process and Selectox processes. Recent innovations in response changing environmental and production requirements have included catalytic and tail gas processes which reduce sulphur emissions. 6 figs., 2 tabs.

Sulphur removal in IGCC projects

Energy Technology Data Exchange (ETDEWEB)

Cross, F. [Parsons (United Kingdom)

1998-12-31

The technology for recovering elemental sulphur from H{sub 2}S bearing gases is well established. The modified Claus Process is the principal work-horse in sulphur recovery and can customarily achieve conversion efficiencies of 95% or better. Nowadays, such a level of recovery is no longer sufficient in most instances and sulphur recovery facility must then include some form of enhanced recovery, usually by treating the Claus tail gas. A number of processes have been introduced to enable the overall recovery to be increased. Recoveries in excess of 99% are both feasible and economic. Use of oxygen in place has become very popular in cases where oxygen is available cheaply or where capacity increases are designed. Most IGCC projects needing an air separation plant would automatically benefit from extending the use of oxygen to the sulphur recovery plant. The most popular route to minimising sulphur emissions in the context of IGCC projects has involved an oxygen based Claus plant followed by tail gas hydrogenation, hydrogen sulphide recovery and its recycle to the Claus section. The recovery of H{sub 2}S from the Claus tail gas can be integrated with the main gas treating system in the gasification plant. The cost advantage of doing so is significant. Parsons has been involved with the technology since 1949 and has been responsible for developments such as the ammonia burning Claus and jointly with Unocal, the BSRP tail gas process and Selectox processes. Recent innovations in response changing environmental and production requirements have included catalytic and tail gas processes which reduce sulphur emissions. 6 figs., 2 tabs.

Past and future trends in concentrations of sulphur and nitrogen compounds in the Arctic

DEFF Research Database (Denmark)

Hole, Lars R.; Christensen, Jesper H.; Ruoho-Airola, Tuija

2009-01-01

Recent trends in nitrogen and sulphur compounds in air and precipitation from a range of Arctic monitoring stations are presented, with seasonal data from the late 70s to 2004 or 2005. Earlier findings of declining sulphur concentrations are confirmed for most stations, while the pattern is less...... clear for reduced and oxidized nitrogen. In fact there are positive trends for nitrogen compounds in air at several stations. Acidity is generally reduced at many stations while the precipitation amount is either increasing or stable. Variability of sulphate concentrations in air for the period 1991......-2000 is reasonably well reproduced at most stations using an Eulerian, hemispherical model. Results for nitrogen compounds are weaker. Scenario studies show that even if large sulphur emission reductions take place in important source regions in South-East Asia in the coming decades, only small changes in Arctic...

Adsorption of mercury (II from liquid solutions using modified activated carbons

Directory of Open Access Journals (Sweden)

Hugo Soé Silva

2010-06-01

Full Text Available Mercury is one of the most toxic metals present in the environment. Adsorption has been proposed among the technologies for mercury abatement. Activated carbons are universal adsorbents which have been found to be a very effective alternative for mercury removal from water. The effectiveness with which a contaminant is adsorbed by the solid surface depends, among other factors, on the charge of the chemical species in which the contaminant is in solution and on the net charge of the adsorbent surface which depend on the pH of the adsorption system. In this work, activated carbon from carbonized eucalyptus wood was used as adsorbent. Two sulphurization treatments by impregnation with sulphuric acid and with carbon disulphide, have been carried out to improve the adsorption capacity for mercury entrapment. Batch adsorption tests at different temperatures and pH of the solution were carried out. The influence of the textural properties, surface chemistry and operation conditions on the adsorption capacity, is discussed.

Corrosion of alloy C-22 in organic acid solutions

International Nuclear Information System (INIS)

Carranza, Ricardo M.; Rodriguez, Martin A.; Giordano, Celia M.

2007-01-01

Electrochemical studies such as cyclic potentiodynamic polarization (CPP) and electrochemical impedance spectroscopy (EIS) were performed to determine the corrosion behavior of Alloy 22 (N06022) in 1M NaCl solutions at various pH values from acidic to neutral at 90 C degrees. All the tested material was wrought Mill Annealed (MA). Tests were also performed in NaCl solutions containing weak organic acids such as oxalic, acetic, citric and picric acids. Results show that the corrosion rate of Alloy 22 was significantly higher in solutions containing oxalic acid than in solutions of pure NaCl at the same pH. Citric and Picric acids showed a slightly higher corrosion rate, and Acetic acid maintained the corrosion rate of pure chloride solutions at the same pH. Organic acids revealed to be weak inhibitors for crevice corrosion. Higher concentration ratios, compared to nitrate ions, were needed to completely inhibit crevice corrosion in chloride solutions. Results are discussed considering acid dissociation constants, buffer capacity and complex formation constants of the different weak acids. (author) [es

Impact of pedospheric and atmospheric sulphur nutrition on sulphur metabolism of Allium cepa L., a species with a potential sink capacity for secondary sulphur compounds

NARCIS (Netherlands)

Durenkamp, M.; De Kok, L.J.

Onion (Afflum cepa L.) was able to use atmospheric H2S as sole sulphur source for growth. The foliarly absorbed H2S was rapidly metabolized into water-soluble, non-protein thiol compounds, including cysteine, and subsequently into other sulphur compounds in the shoots. In H2S-exposed plants, the

Harties' two-man acid plant now fully on stream

International Nuclear Information System (INIS)

Anon.

1979-01-01

Hartebeesfontein gold mine is the most modern of its kind in South Africa. Only two men are required to operate this R12 million acid plant. The plant is capable of producing 140 000 t of sulphuric acid a year, and will meet its own uranium recovery process requirements as well as those of other uranium producers in the Klerksdorp and Stilfontein areas. In simplified form the process involves roasting pyrite to form sulphur dioxide. This is then cleaned, dried, heated and reacted over catalyst to produce sulphur tri-oxide which is combined with water to form sulphuric acid. Where the pyrite is gold-bearing, the resultant calcines from the roasting process are pumped to the mine's recovery plant where the residual gold is extracted. The main reason for the construction of the plant was to supply Hartebeesfontein and other uranium producers in the Klerksdorp and Stilfontein areas with sulphuric acid which is used in the uranium leaching process

Sulphur oxidising bacteria in mangrove ecosystem: A review ...

African Journals Online (AJOL)

Sulphur-oxidizing bacteria such as photoautotrophs, chemolithotrophs and heterotrophs play an important role in the mangrove environment for the oxidation of the toxic sulphide produced by sulphur reducing bacteria and act as a key driving force behind all sulphur transformations in the mangrove ecosystem which is ...

Sulphur-containing compounds in sulphur-rich crude oils from hypersaline lake sediments and their geochemical implications

NARCIS (Netherlands)

Sinninghe Damsté, J.S.; Guoying, S.; Jiamo, F.; Brassell, S.C.; Gowar, A.P.; Eglinton, G.; Leeuw, J.W. de; Schenck, P.A.

1987-01-01

Three sulphur-rich commercial crude oils have been studied, which contain sulphur as high as up to 4 —12 %. These samples were collected from Tertiary hypersaline lake sediments of the Jianghan Basin, Hubei Province at different depths, but above the oil generation threshold (2200m). FPD-GC and

NIR spectroscopic properties of aqueous acids solutions.

Science.gov (United States)

Omar, Ahmad Fairuz; Atan, Hanafi; Matjafri, Mohd Zubir

2012-06-15

Acid content is one of the important quality attributes in determining the maturity index of agricultural product, particularly fruits. Despite the fact that much research on the measurement of acidity in fruits through non-destructive spectroscopy analysis at NIR wavelengths between 700 to 1,000 nm has been conducted, the same response towards individual acids is not well known. This paper presents NIR spectroscopy analysis on aqueous citric, tartaric, malic and oxalic solutions through quantitative analysis by selecting a set of wavelengths that can best be used to measure the pH of the solutions. The aquaphotomics study of the acid solutions has generated R² above 0.9 for the measurement of all acids. The most important wavelengths for pH are located at 918-925 nm and 990-996 nm, while at 975 nm for water.

Vapor mercury uptake with sulphur impregnated active carbons derived using sulphur dioxide

International Nuclear Information System (INIS)

Tong, S.; Methta, H.; Ahmed, I.; Morris, E.; Fuentes de Maria, L.; Jia, C.Q.

2008-01-01

Active carbon adsorption is the primary technology used for removal of vapour mercury from flue gases in coal-fired power plants, municipal solid waste combustors, and other sources. It can be carried out using two different processes, notably injection of powder active carbon into flue gas streams upstream of the particulate collection devices, and filtration with a granular active carbon fixed bed downstream of the flue gas desulphurization units and/or particulate collectors. This paper presented an investigation of vapour mercury uptake performance of laboratory-made sulphur impregnated active carbons (SIACs) using a fixed bed reactor in a temperature range of 25 to 200 degrees Celsius. The materials and methods as well as the properties of activated carbons studied were presented. The experimental set-up was also described. The paper discussed the effects of initial concentration, the flow rate, the loading amount of SIACs, temperature, and the sulphur impregnation on the mercury uptake performance. The study showed that SIACs produced with sulphur dioxide exhibited a more complicated behaviour when temperature was varied, implying a mixed adsorption mechanism. 10 refs., 3 tabs., 8 figs

The useful application of sulphur-bound waste materials

NARCIS (Netherlands)

Alkemade, M.M.C.; Koene, J.I.A.

1996-01-01

An immobilization process is described which is based on sulphur (instead of cement) as a binding agent for the treatment of hazardous waste materials. Elemental sulphur is able to bind chemically metals such as mercury and, to a lesser extent, lead as metal sulphides. Furthermore, sulphur forms a

Utilization of activated carbon loaded with sulphur for sulphur fertilization in agriculture; Verwertung von mit Schwefel beladener Aktivkohle als Schwefelduenger in der Landwirtschaft

Energy Technology Data Exchange (ETDEWEB)

Kirfel, Kristina; Hoffmann, Heide [Humboldt Univ. Berlin (Germany). AG Agraroekologie und Oekologischer Landbau

2013-01-15

Due to the decrease of atmospheric sulphur deposition, sulphur fertilization has gained significance for agriculture in recent years. Carbon-sulphur-pellets (CSP), activated carbon pellets loaded with sulphur, previously used for desulphurization in biogas plants, are up to now disposed of as waste. In this context the question arises if CSP could be of use for sulphur fertilization of agricultural crops. The objective of this study was to test sulphur release and plant availability from, and plant tolerance towards CSP. A pot experiment using Zea mays with different shares of CSP was carried out. Leaf green intensity of vital plants, indicating plants' current nutritional status, was measured and differences in plant development were documented regularly. At the end of the trial period biomass and elemental contents of the test plants, as well as electrical conductivity and pH-value of the substrate-CSP-mixtures were determined. Amendments of 0.2 m.-% to 1.0 m.-% had a positive effect on plants' dry mass yield; higher shares led to considerable yield losses. By addition of CSP, sulphur content in the plant dry mass increased compared to the control without sulphur fertilization. This result indicates that sulphur adsorbed to activated carbon becomes plant available when applicated to cultural substrate. (orig.)

Isolation and fractionation of soil humin using alkaline urea and dimethylsulphoxide plus sulphuric acid

Science.gov (United States)

Song, Guixue; Hayes, Michael H. B.; Novotny, Etelvino H.; Simpson, Andre J.

2011-01-01

Humin, the most recalcitrant and abundant organic fraction of soils and of sediments, is a significant contributor to the stable carbon pool in soils and is important for the global carbon budget. It has significant resistance to transformations by microorganisms. Based on the classical operational definition, humin can include any humic-type substance that is not soluble in water at any pH. We demonstrate in this study how sequential exhaustive extractions with 0.1 M sodium hydroxide (NaOH) + 6 M urea, followed by dimethylsulphoxide (DMSO) + 6% ( v/ v) sulphuric acid (H2SO4) solvent systems, can extract 70-80% of the residual materials remaining after prior exhaustive extractions in neutral and aqueous basic media. Solid-state 13C NMR spectra have shown that the components isolated in the base + urea system were compositionally similar to the humic and fulvic acid fractions isolated at pH 12.6 in the aqueous media. The NMR spectra indicated that the major components isolated in the DMSO + H2SO4 medium had aliphatic hydrocarbon associated with carboxyl functionalities and with lesser amounts of carbohydrate and peptide and minor amounts of lignin-derived components. The major components will have significant contributions from long-chain fatty acids, waxes, to cuticular materials. The isolates in the DMSO + H2SO4 medium were compositionally similar to the organic components that resisted solvation and remained associated with the soil clays. It is concluded that the base + urea system released humic and fulvic acids held by hydrogen bonding or by entrapment within the humin matrix. The recalcitrant humin materials extracted in DMSO + H2SO4 are largely biological molecules (from plants and the soil microbial population) that are likely to be protected from degradation by their hydrophobic moieties and by sorption on the soil clays. Thus, the major components of humin do not satisfy the classical definitions for humic substances which emphasise that these arise from

Containment of Nitric Acid Solutions of Plutonium-238

International Nuclear Information System (INIS)

Reimus, M.A.H.; Silver, G.L.; Pansoy-Hjelvik, L.; Ramsey, K.

1999-01-01

The corrosion of various metals that could be used to contain nitric acid solutions of Pu-238 has been studied. Tantalum and tantalum/2.5% tungsten resisted the test solvent better than 304L stainless steel and several INCONEL alloys. The solvent used to imitate nitric acid solutions of Pu-238 contained 70% nitric acid, hydrofluoric acid, and ammonium hexanitratocerate

Selective separation of indium by iminodiacetic acid chelating resin

International Nuclear Information System (INIS)

Fortes, M.C.B.; Benedetto, J.S.; Martins, A.H.

2007-01-01

- Indium can be recovered by treating residues, flue dusts, slags, and metallic intermediates in zinc smelting. This paper investigates the adsorption characteristics of indium and iron on an iminodiacetic acid chelating resin, Amberlite R IRC748 (Rohm and Haas Co.-USA). High concentrations of iron are always present in the aqueous feed solution of indium recovery. In addition, the chemical behaviour of iron in adsorptive systems is similar to that of indium. The metal concentrations in the aqueous solution were based on typical indium sulfate leach liquor obtained from zinc hydrometallurgical processing in a Brazilian plant. The ionic adsorption experiments were carried out by the continuous column method. Amberlite R IRC748 resin had a high affinity for indium under acidic conditions. Indium ions adsorbed onto the polymeric resin were eluted with a 0.5 mol/dm 3 sulphuric acid solution passed through the resin bed in the column. 99.5% pure indium sulfate aqueous solution was obtained using the iminodiacetic acid chelating resin Amberlite R IRC748. (author)

Modeling of solvent extraction equilibrium of Cu(II from sulphuric Acid solution with MOC-55TD

Directory of Open Access Journals (Sweden)

Alguacil, F. J.

1999-06-01

Full Text Available The extraction of Cu(II from acidic sulphate aqueous solutions using the commercial MOC-55TD extractant is studied. A predictive model, which consists in a set of non-linear mass action and mass balance equations is proposed. The model was solved using a tailor-made equation-solving program. The extraction of copper can be described by the formation of CuR₂ species (log K_ext= 0.717 ± 0.03 in the organic phase. The copper equilibrium isotherm was also obtained at 20°C.

Se estudia la extracción de Cu(II de disoluciones acuosas acidas, en medio sulfato, mediante la oxima comercial MOC-55TD. Se propone un modelo para predecir la extracción del metal; este modelo consiste en una serie de ecuaciones no lineales de acción de masas y balance de masas. El modelo se resolvió empleando un programa de ordenador específicamente definido para este tipo de equilibrios. La extracción de cobre se describe por la formación de la especie CuR₂ (log K_ext= 0,717 ± 0,03 en la fase orgánica. Se ha obtenido la isoterma de extracción de cobre a 20 °C.

Extraction of some acids using aliphatic amines; Extraction de quelques acides par des amines aliphatiques

Energy Technology Data Exchange (ETDEWEB)

Matutano, L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-06-01

Hydrochloric, nitric, sulphuric, perchloric, phosphoric, acetic and formic acids in aqueous solution (0.05 to 10 M) are extracted by amberlite LA2 and trilaurylamine in solution, 5 per cent by volume, in kerosene and xylene respectively. The extraction process consists of: neutralization of the amine salt; a 'molecular extraction', i.e. an extraction using an excess of acid with respect to the stoichiometry of the amine salt. According to the behaviour of the acid during the extraction, three groups may be distinguished: completely dissociated acids, carboxylic acids, phosphoric acid. This classification is also valid for the extraction of the water which occurs simultaneously with that of the acid. An extraction mechanism is put forward for formic acid and the formation constant of its amine salt is calculated. (author) [French] Les acides chlorhydrique, nitrique, sulfurique, perchlorique, phosphorique, acetique et formique, en solution aqueuse - 0,05 a 10 M - sont extraits par l'amberlite LA2 et la trilaurylamine en solution, a 5 pour cent en volume, dans le kerosene et le xylene respectivement. L'extraction comprend: une neutralisation de l'amine par l'acide avec formation d'un sel d'amine; une 'extraction moleculaire', c'est-a-dire une extraction d'acide en exces par rapport a la stoechiometrie du sel d'amine. Suivant le comportement des acides au cours de l'extraction nous distinguons trois groupes: acides entierement dissocies, acides carboxyliques, acide phosphorique. Cette classification est egalement valable pour l'extraction de l'eau qui est simultanee a celle de l'acide. Un mecanisme d'extraction pour l'acide formique est propose et nous calculons la constante de formation de son sel d'amine. (auteur)

Calibration of brachytherapy sources using ferrous sulphate-benzoic acid-xylenol orange dosimeter

International Nuclear Information System (INIS)

Madhvanath, U.; Kini, U.R.; Gupta, B.L.

1976-01-01

A solution containing 0.20 mM of ferrous ammonium sulphate, 5.0 mM benzoic acid and 0.20 mM xylenol orange in 0.05 N sulphuric acid was used for the calibration of 252 Cf, 137 Cs, 226 Ra and 60 Co needle sources. A known volume of this solution contained in a pyrex glass tube was irradiated with the source kept in a glass capillary at the centre of the solution. A few hours of irradiation were required for each needle and the absorbance of the solution was measured at 540 nm against the unirradiated solution. The accuracy of this method was found to be within a few percent and is particularly useful for 252 Cf sources as the neutron component of the source contributes significantly to the absorbance produced. (author)

Nuclear physical express analysis of solid fuel sulphur content

International Nuclear Information System (INIS)

Pak, Yu.; Ponomaryova, M

2005-01-01

Full text: Sulphur content is an important qualitative coal parameter. The problem of coal sulphur content determining remains one of the most important both in Kazakhstan and in other coal-mining countries. The traditional method of sampling, the final stage of which is chemical analysis of coal for sulphur, is characterized by high labour intensity and low productivity. That's why it is ineffective for mass express analytical quality control and technological schemes of coal processing control. In this connection it is very urgent to develop a method of coal sulphur content on the base of a series nuclear-geophysical equipment with an isotope source of primary radiation, allowing to increase analysis representativity and maximally take into account coal real composition inconstancy. To solve the problem set it is necessary to study the main laws of X-ray-radiometric method applied to the coal quality analysis for working out instrumental methods of speed determining of coal sulphur content with satisfactory accuracy for technological tasks, to determine laws of changing the flows of characteristic X-ray and scattered radiation from coal sulphur content of various real composition and to optimize methodical and hardware parameters, providing minimal error of sulphur content control. On the base of studying laws of real composition coal components and their interconnections with sulphur content there has been substantiated the expediency of using hardware functions of calcium and iron to control coal sulphur contents; there has been suggested a model to estimate the methodical error of coal sulphur content determining on the base of the data about sensitivity to sulphur and effecting factors using ultimate methods of coal components substitution methods allowing to optimize sulphur control parameters; there has been worked out an algorithm of X-ray-radiometric control of sulphur content based on the sequential radiating the analyzed coal with gamma-radiation of

Sulphur isotope variations in the atmosphere

International Nuclear Information System (INIS)

Newman, L.; Krouse, H.R.; Grinenko, V.A.

1991-01-01

The measurement of the isotope ratios of sulphur and oxygen can in principal be used to assess sulphur inputs into, transformation within, and removal from the atmosphere. Major inputs arise from both anthropogenic and biogenic activities. Transformations arise from oxidation, neutralization, and other chemical reactions. Advection causes dilution and the main removal processes are dry deposition (governed by gravitation and diffusion) and rain. The admixture of sources can be discerned from their isotopic signatures whereas transformations and removal can be followed from the isotopic fractionation that might occur. In this chapter, the atmospheric sulphur cycle and the associated chemistry are summarized. Also presented is information on natural isotopic variations and fundamental concepts relating to the use of isotopic data to delineate anthropogenic S in the atmosphere. Examples of successful applications of these concepts are given. Finally, consideration is given to the potential of using isotopically enriched sulphur to study transport and transformation of atmospheric S compounds. Refs, figs and tabs

Model radioisotope experiments on the influence of acid rain on 65Zn binding with humic acid

International Nuclear Information System (INIS)

Koczorowska, E.; Mieloch, M.; Slawinski, J.

2002-01-01

Acid rain formed first of all from sulfur oxide emitted by natural and anthropogenic sources, may change the biological equilibrium and the metal stoppage in the soil. The model experiments were performed to determine the influence of acid rain on zinc bond with humic acid (HA). The samples were prepared in glass columns with quartz sand and overlaid HA or HA + 65 Zn radioisotope that simulates natural conditions. Then, solutions of H 2 SO 4 were introduced into the sand - HA layer. Zinc was washed with diluted (10 -4 - 10 -3 M) sulphuric acid as a simulation of acid rain. The results help to evaluate the migration behaviour of zinc in the presence of HA and H 2 SO 4 . The model studies illustrate the considerable influence of sulfuric acid on chemical degradation of HA. (author)

Potentiometric titration of free acid in uranium solutions

International Nuclear Information System (INIS)

Suh, M. Y.; Kim, W. H.; Kim, J. S.; Sohn, S. C.; Eom, T. Y.; Lee, C. H.; Jeon, Y. S.; Han, S. H.

1998-02-01

Hydrolysis properties of metal cations and fundamental principles of the potentiometric titration of free acid in aqueous solutions containing metal cations were described. The published papers and reports for the alkalimetric and acidimetric titration of free acid were surveyed, and the applicability of these titration methods to the uranium and/or plutonium solutions were discussed. This technical report also includes the various results obtained from the authors' researches to establish the alkalimetric and acidimetric titration methods for the determination of free acid in nitric acid solutions containing uranium and/or oxalic acid, and aluminum. The procedure manuals used in chemical processes and the newly prepared manuals based on the authors' researches are appended. (author). 26 refs., 54 figs

Potentiometric titration of free acid in uranium solutions

Energy Technology Data Exchange (ETDEWEB)

Suh, M. Y.; Kim, W. H.; Kim, J. S.; Sohn, S. C.; Eom, T. Y.; Lee, C. H.; Jeon, Y. S.; Han, S. H.

1998-02-01

Hydrolysis properties of metal cations and fundamental principles of the potentiometric titration of free acid in aqueous solutions containing metal cations were described. The published papers and reports for the alkalimetric and acidimetric titration of free acid were surveyed, and the applicability of these titration methods to the uranium and/or plutonium solutions were discussed. This technical report also includes the various results obtained from the authors` researches to establish the alkalimetric and acidimetric titration methods for the determination of free acid in nitric acid solutions containing uranium and/or oxalic acid, and aluminum. The procedure manuals used in chemical processes and the newly prepared manuals based on the authors` researches are appended. (author). 26 refs., 54 figs.

The recovery of sulphur, uranium and gold from residues in OFS scheme

International Nuclear Information System (INIS)

Ruhmer, W.T.; Botha, F.; Adams, J.S.

1978-01-01

This article describes a project comprising three plants for the flotation of pyrite, a twin-stream uranium plant in which high-grade slimes and pyrite can be leached separately, a pyrite burning sulphuric acid plant, and a plant for the recovery of gold from calcines. Details of these plants including capital costs and estimate production are given

Leaching of vanadium from sulphuric acid manufacture spent catalysts

Directory of Open Access Journals (Sweden)

García, Diego Juan

2001-02-01

Full Text Available Recovery of vanadium contained in spent catalysts from the manufacture of sulphuric acid has been studied in this work, resulting in an industrial multistage process for the treatment of them avoiding direct deposition or dumping. Characterization of supplied spent catalysts samples, confirmed vanadium levels showed in the literature. The study of variables influencing leaching process: type of leaching agent, leaching agent concentration, S/L ratio, stirring speed and temperature, allows to fix the most advantageous conditions using industrial application criterion and verifying that the process is difusión controlled. The work is completed by developing an industrial leaching cycle simulation with the aim of reproducing real performance of spent catalyst, proposing operating conditions, and verifying the non-toxic character of the final residue obtained.

En el presente trabajo se ha estudiado la recuperación del vanadio contenido en los catalizadores agotados procedentes de la fabricación del ácido sulfúrico, planteando un proceso industrial multietapa para el tratamiento de estos residuos, evitando su deposición o vertido directos. La caracterización de las muestras de catalizadores agotados disponibles confirmó los valores encontrados en la bibliografía. Se estudiaron las variables que influyen en el proceso de lixiviación (tipo de agente de lixiviación y concentración del mismo, relación S/L, velocidad de agitación y temperatura definiendo las condiciones más adecuadas desde el punto de vista industrial y verificando que el proceso está controlado por mecanismos difusionales. El trabajo se completa con la simulación de un ciclo industrial de lavado del catalizador y la verificación de la nula toxicidad de los lixiviados obtenidos por degradación del residuo final. 24 Aplicación de la resistencia de ruido al estudio de pinturas ricas en zinc Noise resistance applied to the study of zinc rich paints

Biodesulphurisation of high sulphur coal by heap leaching

Energy Technology Data Exchange (ETDEWEB)

J. Cara; M.T. Carballo; A. Moran; D. Bonilla; O. Escolano; F.J. Garcia Frutos [Universidad de Leon, Leon (Spain). Departamento de Ingenieria Quimica

2005-10-01

The biodesulphurisation of coal carried out in pile could be an interesting option to clean coal. In view of the good results obtained in biodesulphurisation test column at lab scale on a sample of semianthracite coal that proceed of an industrial plant with a high sulphur content, mainly pyritic sulphur, the feasibility of the process at pilot plant scale was studied. The pile was formed with 6 ton of gravity middlings coal sample with a grain size -12+0.5 mm from S.A. Hullera Vasco-Leonesa industrial plant. The coal has a total sulphur content of 3.78% and a pyritic sulphur content of 2.88%, the rest of sulphur is organic sulphur. The biodesulphurisation process in pilot plant follows three stages: stabilization of the pile, biodesulphurisation and washing. Heap was sampled twice during stabilisation stage, at the end of desulphurisation process and finally once washed. A pyritic sulphur removal of 39% and total sulphur removal of 23% was obtained. To complete the bioleaching process, the treatment of purge of leachate was carried out with the objective to recycling to head of process. The best treatment was a pre-treatment of the leachate until pH 4, and further treatment by reverse osmosis of the clarified water. Comparing this process with conventional precipitation to reach disposal limits, the reagents consumption and sludges were reduced considerably and due to the high quality of permeate it permits to recycle it to head of process. 18 refs., 6 figs., 6 tabs.

Radiation protection by ascorbic acid in sodium alginate solutions

Energy Technology Data Exchange (ETDEWEB)

Aliste, A.J.; Mastro, N.L. Del [Center of Radiation Technology, IPEN/CNEN/SP, University City, 05508-000 Sao Paulo (Brazil)]. E-mail: ajaliste@ipen.br

2004-07-01

Alginates are gelling hydrocolloids extracted from brown seaweed used widely in the nourishing and pharmaceutical industries. As alginic acid gellification retard food entrance in the stomach alginate is an additive used in diets. The objective of this work was to study the protective action of the ascorbic acid in alginate solutions against the action of {sup 60} Co gamma radiation. One % (w/v) solutions of alginate had been used and concentrations of ascorbic acid varied from 0 to 2.5% (w/v). The solutions were irradiated with doses up to 10 kGy. Viscosity/dose relationship and the p H of the solutions at 25 Centigrade were determined. Ascorbic acid behaved as an antioxidant against radiation oxidative shock in this model system of an irradiated viscous solution. Besides its radiation protective role on alginate solutions ascorbic acid promoted a viscosity increase in the range of concentrations employed. (Author)

Radiation protection by ascorbic acid in sodium alginate solutions

International Nuclear Information System (INIS)

Aliste, A.J.; Mastro, N.L. Del

2004-01-01

Alginates are gelling hydrocolloids extracted from brown seaweed used widely in the nourishing and pharmaceutical industries. As alginic acid gellification retard food entrance in the stomach alginate is an additive used in diets. The objective of this work was to study the protective action of the ascorbic acid in alginate solutions against the action of 60 Co gamma radiation. One % (w/v) solutions of alginate had been used and concentrations of ascorbic acid varied from 0 to 2.5% (w/v). The solutions were irradiated with doses up to 10 kGy. Viscosity/dose relationship and the p H of the solutions at 25 Centigrade were determined. Ascorbic acid behaved as an antioxidant against radiation oxidative shock in this model system of an irradiated viscous solution. Besides its radiation protective role on alginate solutions ascorbic acid promoted a viscosity increase in the range of concentrations employed. (Author)

Effect of postreatment on the corrosion behaviour of tartaric-sulphuric anodic films

Energy Technology Data Exchange (ETDEWEB)

Garcia-Rubio, M. [Departamento de Quimica-Fisica Aplicada, Universidad Autonoma de Madrid, 28049 Madrid (Spain); Department of Surface Technologies, Engineering of Materials and Processes, Airbus Spain, Av. John Lennon s/n 28906 Getafe (Spain); Lara, M.P. de [Departamento de Quimica-Fisica Aplicada, Universidad Autonoma de Madrid, 28049 Madrid (Spain); Ocon, P. [Departamento de Quimica-Fisica Aplicada, Universidad Autonoma de Madrid, 28049 Madrid (Spain)], E-mail: pilar.ocon@uam.es; Diekhoff, S. [Fraunhofer-IFAM, Lesumer Heerstrasse 36, 28717 Bremen (Germany); Beneke, M. [Department of Surface Technologies, Engineering of Materials and Processes, Airbus Deutschland, GmbH Hunefeldstr. 1-5, 28199 Bremen (Germany); Lavia, A.; Garcia, I. [Department of Surface Technologies, Engineering of Materials and Processes, Airbus Spain, Av. John Lennon s/n 28906 Getafe (Spain)

2009-08-30

Unclad and clad AA2024 T3 specimens were anodised in a chromium-free tartaric-sulphuric acid bath (TSA) and subsequently postreated by different processes including impregnation in a cold, concentrated chromate solution, Cr-free hot-water sealing, and dichromate hot-water sealing. The purpose of this work is to evaluate the effectiveness of the classical postreatments used in the aircraft industry on the TSA-anodic films and their corrosion resistance behaviour. TSA-anodic films were characterised by scanning electron microscopy (SEM) and their thicknesses were measured by SEM and the eddy current method. Electrochemical impedance spectroscopy (EIS) was used to characterise the barrier and porous layers, and jointly with potentiodynamic polarisation allowed the evaluation of corrosion resistance parameters with immersion time in NaCl solution for anodised and postreated specimens. In all cases the postreatments increased the resistance of the barrier layer against degradation. However, the NaCl electrolyte easily penetrated TSA-anodised porous layers when they were not postreated, while penetration was slightly more difficult in cold-postreated specimens. The effective pore plugging was observed in the sealed TSA specimens resulting in an improved corrosion resistance. On the other hand, unsealed clad AA2024 specimens showed a self-sealing process of the TSA-anodic layer, which was slower for the cold chromate solution-postreated specimens.

Effect of postreatment on the corrosion behaviour of tartaric-sulphuric anodic films

International Nuclear Information System (INIS)

Garcia-Rubio, M.; Lara, M.P. de; Ocon, P.; Diekhoff, S.; Beneke, M.; Lavia, A.; Garcia, I.

2009-01-01

Unclad and clad AA2024 T3 specimens were anodised in a chromium-free tartaric-sulphuric acid bath (TSA) and subsequently postreated by different processes including impregnation in a cold, concentrated chromate solution, Cr-free hot-water sealing, and dichromate hot-water sealing. The purpose of this work is to evaluate the effectiveness of the classical postreatments used in the aircraft industry on the TSA-anodic films and their corrosion resistance behaviour. TSA-anodic films were characterised by scanning electron microscopy (SEM) and their thicknesses were measured by SEM and the eddy current method. Electrochemical impedance spectroscopy (EIS) was used to characterise the barrier and porous layers, and jointly with potentiodynamic polarisation allowed the evaluation of corrosion resistance parameters with immersion time in NaCl solution for anodised and postreated specimens. In all cases the postreatments increased the resistance of the barrier layer against degradation. However, the NaCl electrolyte easily penetrated TSA-anodised porous layers when they were not postreated, while penetration was slightly more difficult in cold-postreated specimens. The effective pore plugging was observed in the sealed TSA specimens resulting in an improved corrosion resistance. On the other hand, unsealed clad AA2024 specimens showed a self-sealing process of the TSA-anodic layer, which was slower for the cold chromate solution-postreated specimens.

Studies on removal of plutonium from oxalic acid containing hydrochloric acid solutions

Energy Technology Data Exchange (ETDEWEB)

Ghadse, D R; Noronha, D M; Joshi, A R [Fuel Chemistry Division, Bhabha Atomic Research Centre, Mumbai (India)

1994-06-01

Solution containing hydrochloric acid, oxalic acid and considerable quantities of plutonium may be generated while recycling of scrap produced during the metallic fuel fabrication. Plutonium from such waste is normally recovered by anion exchange method after the destruction of oxalic acid using suitable oxidising agent. Solvent extraction and ion exchange methods are being explored in this laboratory for recovery of Pu from oxalic acid containing HCl solutions without prior destruction of oxalic acid. This paper describes the results on the determination of distribution ratios for extraction of Pu(IV) from hydrochloric acid using Aliquot-336 or HDEHP under varying experimental conditions. (author). 5 refs., 5 tabs.

Corrosion Inhibition of Aluminium in Acid Media By Citrullus Colocynthis Extract

Directory of Open Access Journals (Sweden)

Rajkiran Chauhan

2011-01-01

Full Text Available Inhibition of corrosion of aluminium in acid solution by methanol extract of Citrullus colocynthis plant has been studied using mass loss and thermometric measurements. It has been found that the plant extract act as a good corrosion inhibitor for aluminium in all concentrations of sulphuric and hydrochloric acid solution. The inhibition action depends on the concentration of acid and inhibitor. Results for mass loss and thermometric measurement indicate that inhibition efficiency increase with increasing inhibitor concentration. The inhibition action of the plant extract is discussed in view of Langmuir adsorption isotherm. It has been observed that the adsorption of the extract on aluminium surface is a spontaneous process. The plant extract provides a good protection to aluminium against corrosion.

The role of phosphate additive in stabilization of sulphuric-acid-based vanadium(V) electrolyte for all-vanadium redox-flow batteries

Science.gov (United States)

Roznyatovskaya, Nataliya V.; Roznyatovsky, Vitaly A.; Höhne, Carl-Christoph; Fühl, Matthias; Gerber, Tobias; Küttinger, Michael; Noack, Jens; Fischer, Peter; Pinkwart, Karsten; Tübke, Jens

2017-09-01

Catholyte in all-vanadium redox-flow battery (VRFB) which consists of vanadium salts dissolved in sulphuric acid is known to be stabilized by phosphoric acid to slow down the thermal aging at temperatures higher than 40 °C. To reveal the role of phosphoric acid, the thermally-induced aggregation is investigated using variable-temperature 51V, 31P, 17O, 1H nuclear magnetic resonance (NMR) spectroscopy and dynamic light scattering (DLS). The results indicate that the thermal stabilization of vanadium(V) electrolyte is attained by the involvement of monomeric and dimeric vanadium(V) species in the reaction with phosphoric acid which is concurrent to the formation of neutral hydroxo-aqua vanadium(V) precipitation precursor. The dimers are stabilized by counter ions due to association reaction or if such stabilization is not possible, precipitation of vanadium pentoxide is favored. The evolution of particles size distributions at 50 °C in electrolyte samples containing 1.6 M vanadium and 4.0 M total sulphate and the pathways of precipitate formation are discussed. The optimal total phosphate concentration is found to be of 0.15 M. However, the induction time is assumed to be dependent not only on the total phosphate concentrations, but also on the ratio of total vanadium(V) to sulphate concentrations.

Sulphur containing novel extractants for extraction-separation of palladium (II)

International Nuclear Information System (INIS)

Shukla, J.P.; Sawant, S.R.; Anil Kumar; Singh, R.K.

1995-01-01

Extraction performance of palladium (II) by sulphur containing extragents has unequivocally established their strong extraction ability toward this thiophilic soft metal. Hence a comprehensive investigative study was initiated by us to examine selective reversible extraction-separation of trace and macro amounts of palladium (II) from both aqueous nitric acid as well as hydrochloric acid media into 1,2-dichloroethane by 1,10-dithia-18 crown-6 (1,10-DT18C6), S 6 -pentano-36 (S 6 -P-36) and bis (2-ethylhexyl) sulphoxide (BESO) dissolved in toluene. From the study of aqueous phase acidity, reagent concentration, period of equilibration, diluent, strippant and diverse ions, conditions are established from its quantitative and reversible extraction. Recovery of Pd(II) from loaded thiacrown and sulphoxide phase is easily accomplished by using sodium thiocyanate, ammonium thiocyanate, thiourea, sodium thiosulphate and mixture of (2M Na 2 CO 3 + 0.5 NH 4 OH) (only for BESO) as the strippants. The lack of interference from even appreciable amounts of contaminants like 137 Cs, 106 Ru, 233 U and 239 Pu may be considered as one of the outstanding advantages of the method. Application of these extractants has been successfully tested for the recovery of palladium from high active waste matrix. The extracted complex from both the thiacrowns has been characterized by elemental analyses and UV-Visible spectra, confirmed to be PdA 2 .T (A = NO - 3 , Cl - ) from dilute (pH ∼ 2) acid solutions while composition of organic species with palladium for the sulphoxide, has also been confirmed to be disolvate of the type Pd(NO 3 ) 2 .2BESO. (author). 52 refs., 6 tabs., 6 figs

Potential to reduce emissions of sulphur dioxide through reducing sulphur levels in heavy and light fuel oils - a discussion paper

International Nuclear Information System (INIS)

Tushingham, M.; Bellamy, J.

2001-01-01

Background information on the sulphur levels in light fuel oil (used in residential heating) and heavy fuel oil (used as industrial fuel oil) is provided. In addition to the description of sulphur levels in light and heavy fuel oils, the report also provides a summary of regulatory limits in Canada and elsewhere, and a description of the emission benefits of decreasing sulphur in fuels. 4 refs., 10 tabs., 12 figs

Effect of strong acids on red mud structural and fluoride adsorption properties.

Science.gov (United States)

Liang, Wentao; Couperthwaite, Sara J; Kaur, Gurkiran; Yan, Cheng; Johnstone, Dean W; Millar, Graeme J

2014-06-01

The removal of fluoride using red mud has been improved by acidifying red mud with hydrochloric, nitric and sulphuric acid. The acidification of red mud causes sodalite and cancrinite phases to dissociate, confirmed by the release of sodium and aluminium into solution as well as the disappearance of sodalite bands and peaks in infrared and X-ray diffraction data. The dissolution of these mineral phases increases the amount of available iron and aluminium oxide/hydroxide sites that are accessible for the adsorption of fluoride. However, concentrated acids have a negative effect on adsorption due to the dissolution of these iron and aluminium oxide/hydroxide sites. The removal of fluoride is dependent on the charge of iron and aluminium oxide/hydroxides on the surface of red mud. Acidifying red mud with hydrochloric, nitric and sulphuric acid resulted in surface sites of the form ≡SOH2(+) and ≡SOH. Optimum removal is obtained when the majority of surface sites are in the form ≡SOH2(+) as the substitution of a fluoride ion does not cause a significant increase in pH. This investigation shows the importance of having a low and consistent pH for the removal of fluoride from aqueous solutions using red mud. Copyright © 2014 Elsevier Inc. All rights reserved.

Extraction of cesium from acid solutions

International Nuclear Information System (INIS)

Katykhin, G.S.; Simonov, A.S.

1983-01-01

The extraction of cesium from acidic solutions is studied. Halogen-substituted carboxylic acids were chosen for the aqueous phase and nitrobenzene the diluent. The distribution coefficients are determined by the use of radioactive tracers 134 Cs and 137 Cs. It is believed that large singly charged anions of strong acids are necessary for the extraction of cesium. Metal halide acids are selected for supplying the anions

Source of sulphur in the Ebro Basin (Northern Spain). Tertiary nonmarine evaporite deposits as evidenced by sulphur isotopes

International Nuclear Information System (INIS)

Birnbaum, S.J.; Coleman, D.

1979-01-01

The Ebro Basin is an intermontane basin, located in northern Spain, filled with Tertiary (largely Oligocene and Miocene) elastic and chemical deposits. Sulphur isotopes are utilized to determine the source of sulphur in the sulphate deposits (predominantly gypsum with accessory thenardite, mirabolite and epsomite). Data obtained from Tertiary gypsum rocks produce a range of delta 34 S values from +9.16% to + 14.02% with a mean of +13.61%. Data obtained from Triassic gypsum rocks (in source area) produce a range from +13.73% to +15.14%, with a mean of +14.66%. Values for Tertiary marine water range from +18% to +24%. These data indicate a nonmarine origin for sulpur within the Tertiary sulphate rocks. The contribution of Triassic sulphur to the groundwater system, plus varying degrees of dilution by isotopically lighter (atmospheric and sulphide) sulphur, best explains the isotopic ratios observed in the Tertiary Basin deposits. (Auth.)

Removal of plutonium from nitric acid-oxalic acid solutions using anion exchange method

International Nuclear Information System (INIS)

Kasar, U.M.; Pawar, S.M.; Joshi, A.R.

1999-01-01

An anion exchange method using Amberlyst A-26 (MP) resin was developed for removal of Pu from nitric acid-oxalic acid solutions without destroying oxalate. The method consists of sorption of Pu(IV) on Amberlyst A-26, a macroporous anion exchange resin, from nitric acid-oxalic acid medium in the presence of Al(NO 3 ) 3 . Pu(IV) breakthrough capacity of Amberlyst A-26 using synthetic feed solution was determined. (author)

Development of the floating sulphur biofilm reactor for sulphide ...

African Journals Online (AJOL)

Development of the floating sulphur biofilm reactor for sulphide oxidation in biological water treatment systems. ... The effect of influent sulphide concentrations, flow rate and reactor dimensions on the sulphur biofilm formation were investigated for the optimisation of elemental sulphur recovery and sulphide removal ...

Determination of uranium in aqueous solutions by HPLC post column UV/VIS detection

International Nuclear Information System (INIS)

Abbasi, W.A.; Street, M.

1995-01-01

Analysis of uranium in different nitric acid concentration solutions is interest in nuclear industry where it is present in various process and waste streams. A method for the determination of uranium(VI) in nitric acid solution in described using ion chromatography and post-column derivatization with 4-(2-pyridylazo) resorcinol (PAR). The method does not require any sample treatment for acid removal or neutralization and can be used for routine laboratory analysis. The effluent used was ammonium sulphate / sulphuric acid and PAR was present in ammonium hydroxide/acetic acid buffer. The column effluents is reacted with PAR in a reaction coil and U(VI)-PAR complex is detector at 528 nm. The lowest uranium concentration detected was 100 ppb (0.1 mg/sup -1/) and linearity of up to 8 mgl -1 concentration was verified. The standard deviation in reproducibility at uranium concentration of 0.1 mgl/sup -1/ was 0.82%. (author)

How sulphur was dislodged to sustain plant operation

International Nuclear Information System (INIS)

Verma, A.N.; Agarwal, A.K.

1997-01-01

Heavy Water Plant (Kota) employs chemical exchange between water and hydrogen sulphide gas. Formation of sulphur is a known phenomena during production of heavy water in G.S. process plants. It is observed that after three years of plant operation this sulphur is enough to choke the cold tower trays causing flooding of exchange towers and resultant decrease in throughput. G.S. process plants normally go for major turn around once in four years when sulphur is either manually cleaned or removed by steam wash after hydrogen sulphide gas has been removed from the system and towers have been fully decontaminated. As throughput starts decreasing after third year and plant operation becomes more difficult in fourth year, HWP (Kota) had evolved a procedure of heating the towers for dislodging sulphur from sieve trays when plant is running. With these procedures plant operation could be sustained without tower floodings even in fourth year, before plant could go for major turn around for manual removal of sulphur

Evaluation of the protein concentration in enzymes via the determination of sulphur by TXRF

International Nuclear Information System (INIS)

Mertens, M.; Rittmeyer, C.; Kolbesen, B.O.

2000-01-01

Total reflection x-ray fluorescence spectrometry (TXRF) offers many advantages for the identification of trace elements in biological samples like enzymes, tissues or plants. Without any preliminary treatment elements may be determined with high accuracy especially transition metals like Fe, Ni, Cu, Mo and the alkaline earth metal Ca. A further aspect of the investigation of enzymes is the simple and simultaneous determination of light elements. Especially sulphur is of interest. The element sulphur exists mainly in the two amino, acids methionine and cysteine as well as in iron-sulphur clusters and may be used for an easy and simultaneous calculation of the protein concentration. Hence the quantitative determination of sulphur by TXRF allows a cross-check regarding of the conventional quantitative determination of protein concentration by, for example, the Lowry method. On the basis of three enzymes of different origins and molecular weights the presentation will show the influence of the bio-organic matrix and different buffer media on element determination by TXRF. As is already known the influence of the matrix on the detection of light elements is stronger than on transition metals. It can be discussed whether layer thickness and layer effects of the drying residues (characterization by SEM and thickness profilometer (ALPHA-step)) and / or self absorption effects as well as the excitation are of significance. The results indicate that with enzymes of low molecular weight a reliable determination of sulphur is possible whereas those with higher molecular weights gave poorer results on account of the matrix effects described. (author)

A comparison of decontamination effects of commercially available detergents in rats pre-exposed to topical sulphur mustard.

Science.gov (United States)

Misik, Jan; Jost, Petr; Pavlikova, Ruzena; Vodakova, Eva; Cabal, Jiri; Kuca, Kamil

2013-06-01

The genotoxic vesicant sulphur mustard [bis-2-(chloroethyl)sulphide] is a chemical warfare agent which is easily available due to its relatively simple synthesis. Thus, sulphur mustard is a potential agent for mass contamination. In this study, we focused on sulphur mustard toxicity and decontamination in a rat model using commercially available detergent mixtures for dermal decontamination. Male Wistar rats were percutaneously treated with sulphur mustard and subjected to wet decontamination 2 min postexposure. Commercially produced detergents Neodekont™, Argos™, Dermogel™ and FloraFree™ were tested for their decontamination efficacy against an exposed group and their protective ratios determined. The results showed that all tested detergent solutions produced an increase in the median lethal dose [LD(50) = 9.83 (5.87-13.63) mg·kg(-1)] in comparison to controls, which led to increased survival of experimental animals. In general, all tested detergents provided modest decontamination efficacy (PR = 2.0-5.7). The highest protective ratio (5.7) was consistently achieved with Argos™. Accordingly, Argos™ should be considered in further investigation of mass casualty decontamination.

Density of nitric acid solutions of plutonium; Densite des solutions nitriques de plutonium

Energy Technology Data Exchange (ETDEWEB)

Guibergia, J P [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1960-07-01

The report is intended to furnish an expression making it possible to determine the density of a nitric acid solution of plutonium. Under certain defined experimental conditions, the equation found makes it possible to deduce, for a solution whose concentration, free acidity and temperature are known, the corresponding value of the density of that solution. (author) [French] L'expose a pour but de donner une formule permettant la determination de la densite d'une solution nitrique de plutonium. Suivant certaines conditions experimentales precisees, l'equation trouvee permet, pour une solution dont la concentration, l'acidite libre nitrique et la temperature sont donnees, de deduire la valeur correspondant de la densite de cette solution. (auteur)

Organic sulphur in macromolecular sedimentary organic matter. II. Analysis of distributions of sulphur-containing pyrolysis products using multivariate techniques

NARCIS (Netherlands)

Sinninghe Damsté, J.S.; Eglinton, T.I.; Pool, W.; Leeuw, J.W. de; Eijkel, G.; Boon, J.J.

1992-01-01

This study describes the analysis of sulphur-containing products from Curie-point pyrolysis (Py) of eighty-five samples (kerogens, bitumen, and petroleum asphaltenes and coals) using gas chromatography (GC) in combination with sulphur-selective detection. Peak areas of approximately forty individual

Study of free acidity determinations in aqueous solution

International Nuclear Information System (INIS)

Kergreis, A.

1966-04-01

The object of this work is the study of the principal methods which can be applied to the measurement of 'free' acidity. In the first part, we define the various types of acidity which can exist in aqueous solution; then, after having studied some hydrolysis reactions, we compare the value of the neutralisation pH of the hydrated cation and that of the precipitation of the hydroxide. In the second part we have started to study the determination of the acidity of an aqueous solution. After having rapidly considered the 'total' acidity determination, we deal with the problem of the 'free' acidity titration. We have considered in particular certain methods: extrapolation of the equivalent point, colorimetric titrations with or without a complexing agent, and finally the use of ion-exchange resins with mixed aqueous and solvent solutions. (author) [fr

Antioxidant and antibacterial properties of Ziziphus mucronata and ...

African Journals Online (AJOL)

sulphuric acid reagent, Fehling's solution, concentrated sulphuric acid, ferric chloride, Drangendorff's reagent, acetic anhydride, 2, 2-diphenyl-1-picrylhydrazyl (DPPH), p-iodonitrotetrazolium violet, Methods: Antibacterial activity was evaluated using ...

Recovery of fission products from acidic waste solutions thereof

International Nuclear Information System (INIS)

Carlin, W.W.; Darlington, W.B.; Dubois, D.W.

1975-01-01

Fission products, e.g., palladium, ruthenium and technetium, are removed from aqueous, acidic waste solutions thereof. The acidic waste solution is electrolyzed in an electrolytic cell under controlled cathodic potential conditions and technetium, ruthenium, palladium and rhodium are deposited on the cathode. Metal deposit is removed from the cathode and dissolved in acid. Acid insoluble rhodium metal is recovered, dissolved by alkali metal bisulfate fusion and purified by electrolysis. In one embodiment, the solution formed by acid dissolution of the cathode metal deposit is treated with a strong oxidizing agent and distilled to separate technetium and ruthenium (as a distillate) from palladium. Technetium is separated from ruthenium by organic solvent extraction and then recovered, e.g., as an ammonium salt. Ruthenium is disposed of as waste by-product. Palladium is recovered by electrolysis of an acid solution thereof under controlled cathodic potential conditions. Further embodiments wherein alternate metal recovery sequences are used are described. (U.S.)

The method of determination of micro quantities of labeled iodide in carrier free Na125 solution

International Nuclear Information System (INIS)

Kholbaev, A.Kh.; Shilin, E.A.

1996-01-01

The method of determination of microquantities of labelled iodide in Na 125 carrier-free solution was elaborated. This method permits to increase the sensitivity and radiation protection of the determination of labeled iodide. It includes oxidation of iodide by iodate in diluted sulphuric acid with molar concentration 0,03-0,04 mole/l. The extraction of I 2 is made by toluene. The coloured solution is made and optical density is measured at λ=640 nm at the 10 mm optical path .(A.A.D.)

Velocity of crack growing of Inconel-600, sensitized, contaminated with sulphur in PWR type reactors

International Nuclear Information System (INIS)

Castano, M. L.; Blazquez, F.; Gomez Briceno, D.; Lagares, A.

1998-01-01

The origin of the vessel head penetration cracking of Jose Cabrera NPP has been attributed to an IGA/SCC process in a highly sensitized Alloy 600 assisted by sulphur species, as both acid sulphates and reduced species originated by the thermal breakdown of the cationic resins present in the primary coolant. The thermal degradation of the cationic resins leads sulphonic acid group scission and sulphates. Under the operating conditions the reduction of sulphates to sulphides is produced. The sulphides formed from the reduction of sulphate can precipitate with metallic cations and be incorporated into the oxide layers of the materials, preferably into nickel alloys. Others components at Jose Cabrera NPP are fabricated from sensitized alloy 600, as bottom vessel penetrations. In order to determine the influence of sulphur incorporated to the oxide layers of bottom vessel penetration alloy 600, an experimental work has been performed to obtained crack growth rate data under PWR primary conditions on sensitized alloy 600. (Author) 5 refs

Study of the corrosion of metallic coatings and alloys containing aluminum in a mixed atmosphere - sulphur, oxygen - at high temperatures

International Nuclear Information System (INIS)

Fellmann, Daniel

1982-01-01

The objective of this research thesis is the development of materials for a sulphur experimental loop allowing the thermodynamic properties of such an energy cycle to be checked. As solutions must comply with industrial methods, rare materials are excluded as they are too expensive or difficult to implement. Iron-based materials have been tested but could not have at the same time a good corrosion resistance and high temperature forming and mechanical toughness properties. Therefore, metallic coatings have been chosen, specifically alumina. After having reported a bibliographical study on corrosion by sulphur vapour and by oxygen and by sulphur-oxygen, the author presents the experimental materials and methods. Then, the author reports the study of mixed corrosion (by sulphur and oxygen together) of metallic alloys (ferritic and austeno-ferritic alloys, aluminium and titanium alloys), and of the corrosion of FeAlx coatings, of AlTix alloys [fr

Process for treatment of pyrochlore concentrates

International Nuclear Information System (INIS)

Charlot, G.

1976-01-01

A continuous process is described for extraction of niobium, rare earths and thorium from niobium ore concentrates which includes digesting the ore with a hot solution containing 13 to 16 moles of sulphuric acid per liter, diluting the solution to a concentration of 10 to 13 moles of sulphuric acid per liter, separating the insolubles from the solution which includes alkaline earth sulphates and the sulphates of thorium and rare earths that are present, reducing titanium in solution to the trivalent state and diluting the solution to a concentration of 5 to 7 moles of sulphuric acid per liter, separating the precipitated niobium oxide and sulphates of thorium and rare earths, and then concentrating the resulting solution to the level desired for recycle to the digestion stage. 10 Claims, No Drawings

In situ structure solution of helical sulphur at 3 GPa and 400 C

International Nuclear Information System (INIS)

Crichton, W.A.; Vaughan, G.B.M.; Mezouar, M.

2001-01-01

The structure of a 2-chain helical form of sulphur with 9 atoms per unit-cell has been determined from powder synchrotron X-ray diffraction data obtained at 3 GPa and 400 C, using a combination of global optimization, simulated annealing and Rietveld refinement techniques. Final refinement of the structure in trigonal space group P3 2 21 (no. 154) results in a = 7.0897(2) A, c = 4.30238(9) A and V = 187.282(10) A 3 . There are two unique S sites per unit cell, the general S1 6c position with x = 0.7727(9), y = 0.3067(11) and z = 0.6105(12) and the S2 3b with x = 0.8755(8) A. Bond length and angle analysis shows S1-S1 = 2.070(4) A and S2-S2 = 2.096(7) A with an helical S1-S1-S1 divalent angle of 102.7(2) and 101.7(3) for S2-S2-S2. The 2 helices formed, contrary to other polymeric sulphur phases (principally, ψ-S), are non-chiral and evidently have repeats along the (001) translation; that is one turn includes each of the 3 equivalent atoms about the 3 2 -screw axis (S1 helix) and vertex (S2) of the cell. This phase, although temperature quenchable, is observed to back transform to a 4.04 A phase at pressures less than 0.5 GPa. It is likely that this phase represents the true form of the phase XII of Vezzoli and Walsh. (orig.)

Development of a Linear Flow Channel Reactor for sulphur removal ...

African Journals Online (AJOL)

2013-09-23

Sep 23, 2013 ... gation of sulphur production in floating sulphur biofilms as a means for addressing this problem. These 50 µm ... Preliminary studies on the use of the FSB system for sulphur removal in Integrated Managed Passive Treatment ...

Distribution of sulphur into products from waste tire pyrolysis

International Nuclear Information System (INIS)

Susa, D.; Haydary, J.; Markos, J.

2012-01-01

Tire pyrolysis is getting growing attention as an effective waste tire disposal method in comparison to environmentally less friendly methods like dumping or incineration. But the scrap tire sulphur content can be a potential obstacle to scrap tire utilization as a fuel. In this paper the distribution of sulphur into tire pyrolysis yields, solid (char) and liquid (tar), was investigated. The pyrolysis experiments were carried out under different conditions to determine the partitioning of sulphur into pyrolysis products. The influence of different temperatures and reaction times was investigated in a laboratory flow reactor under nitrogen atmosphere. Solid and liquid residues were collected and analyzed by elemental analysis. The sulphur content in residual char and tar was determined using an elemental analyzer and the sulphur forms in tar were characterized by the X-ray photoelectron spectroscopy (XPS). (Authors)

Photochemical reactions of neptunium in nitric acid solution containing photocatalyst

International Nuclear Information System (INIS)

Fukasawa, Tetsuo; Kawamura, Fumio

1991-01-01

Photochemical oxidation and reduction behaviors of neptunium were preliminarily investigated in 3 mol/l nitric acid solution. Nitric acid of 3 mol/l simulated the high level waste solution from a spent fuel reprocessing process. Concentrations of Np(V), Np(VI) and nitrous acid were determined with a photospectrometer, and solution potential with an electrode. Without additives, Np(VI) was reduced to Np(V) by nitrous acid which was photolytically generated from nitric acid. With a scavenger for nitrous acid, Np(V) was oxidized to extractable Np(VI) by a photolytically generated oxidizing reagent which were predicted by the solution potential measurement. The reduction rate was higher than the oxidation rate because of the larger quantity and higher reactivity of nitrous acid than an oxidizing reagent. Photocatalyst was proved to be effective for the oxidation of Np(V) to Np(VI). (author)

Discontinuities in Jovian sulphur plasma

Energy Technology Data Exchange (ETDEWEB)

Mekler, Y [Jet Propulsion Lab., Pasadena, CA (USA); Eviatar, A; Siscoe, G L

1979-10-01

In recent years, the Jovian sulphur nebula, which is the only component of the thermal plasma in the magnetosphere of Jupiter which emits in the visible, has been the subject of considerable study. A large number of investigators have come up with widely differing models for the density, composition and temperature of the Jovian magnetospheric plasma. In this paper a different characteristic of the sulphur emission, namely its radial distribution is discussed and an attempt is made to assess its implications for the plasma and magnetic field configuration of the inner magnetosphere of Jupiter.

The method of determination of micro quantities of labelled iodide in Na125 I carrier free solution

International Nuclear Information System (INIS)

Kholbaev, A.Kh.; Shilin, E.A.

1996-01-01

The analytical method was elaborated with the purpose to increase detection limit and radiation safety of labelled iodide determination. The method includes oxidation of iodide by iodate in diluted sulphur acid solution with molar concentration 0,03-0,04/moles/litre at molar ratio of iodide to iodate I - :IO - 3 1:12,5. The extraction of I 2 produced is done by toluene. (author)

Extraction of uranium from phosphoric-hydrobromic acid mixture by N-lauryl tri alkyl methylamine

Energy Technology Data Exchange (ETDEWEB)

Guirguis, L A [Nuclear materials authority, Cairo, (Egypt); Tadros, N A [Hot laboratories center, atomic energy authority, Cairo, (Egypt)

1995-10-01

A uranium recovery process from phosphoric acid produced by the dihydrate method was elaborated. Decomposition of phosphate rock containing 0.02% U is carried out with sulphuric acid. Crude phosphoric acid is filtered off, steam concentrated to 45% P{sub 2} O{sub 5} (6.27 M) and then clarified with activated clay and carbon. The clear phosphoric acid is introduced to uranium extraction after the addition of 0.88 M hydrobromic acid by 0.134 M amberlite LA.2 and 5% decanol, as a modifier, in kerosene. While 10% ammonium sulphate solution is used for stripping. Over 90% uranium recovery is obtained. 6 figs., 1 tab.

Investigation of DBS electro-oxidation reaction in the aqueous-organic solution of LiClO{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Darlewski, Witold [Military University of Technology, Institute of Chemistry, Kaliskiego Street 2, 00-908 Warszawa (Poland); Popiel, Stanislaw, E-mail: spopiel@wat.edu.pl [Military University of Technology, Institute of Chemistry, Kaliskiego Street 2, 00-908 Warszawa (Poland); Nalepa, Tomasz [Department of Defense Affairs of the Ministry of Economy, Plac Trzech Krzyzy 3/5, 00-507 Warszawa (Poland); Gromotowicz, Waldemar [Warsaw Pharmaceutical Plant ' Polfa' S.A., Karolkowa Street 22/24, 01-207 Warszawa (Poland); Szewczyk, Rafal [Department of Biology and Environment Protection, University of Lodz, Pilarskiego Street 14/16, 90-231 Lodz (Poland); Stankiewicz, Romuald [Warsaw University, Department of Physics, Hoza Street 69, 00-681 Warszawa (Poland)

2010-03-15

A process of dibutyl sulphide (DBS) electro-oxidation using electrolysis and cyclic voltamperometry was investigated in water-methanol solution using different electrodes (platinum, boron doped diamond, graphite and glassy carbon). Obtained results indicate that the DBS electro-oxidation process is irreversible in voltamperometric conditions. It was shown that during DBS electrolytic oxidation on Pt, at the low anode potential (1.8 V), DBS was oxidized to sulphoxide and sulphone. Electrolysis at higher potential (up to 3.0 V) resulted in complete DBS oxidation and formation of various products, including: butyric acid, sulphuric acid, butanesulphinic acid, butanesulphonic acid, identified using gas chromatography (GC-AED) and mass spectrometry (GC-MS) methods.

Thermodynamic properties of aqueous solutions with citrate ions. Compressibility studies in aqueous solutions of citric acid

International Nuclear Information System (INIS)

Apelblat, Alexander; Korin, Eli; Manzurola, Emanuel

2013-01-01

Highlights: • Over a wide range of concentrations and temperatures sound velocities were measured in aqueous solutions of citric acid. • Compressibility properties of citric acid solutions are thermodynamically characterized. • Changes in the structure of water when citric acid is dissolved are discussed. -- Abstract: Sound velocities in aqueous solutions of citric acid were measured from 15 °C to 50 °C in 5 °C intervals, within the 0.1 mol · kg −1 to 5.0 mol · kg −1 concentration range. These sound velocities served to evaluate the isentropic and isothermal compressibilities, the apparent molar compressibilities, the isochoric thermal pressure coefficients, changes of the cubic expansion coefficients with pressure at constant temperature, the changes of heat capacities with volume and hydration numbers of citric acid in aqueous solutions

SOSA – a new model to simulate the concentrations of organic vapours and sulphuric acid inside the ABL – Part 1: Model description and initial evaluation

DEFF Research Database (Denmark)

Boy, M.; Sogachev, Andrey; Lauros, J.

2010-01-01

Chemistry in the atmospheric boundary layer (ABL) is controlled by complex processes of surface fluxes, flow, turbulent transport, and chemical reactions. We present a new model SOSA (model to simulate the concentration of organic vapours and sulphuric acid) and attempt to reconstruct the emissions...... in the surface layer we were able to get a reasonable description of turbulence and other quantities through the ABL. As a first application of the model, we present vertical profiles of organic compounds and discuss their relation to newly formed particles....

SOSA – a new model to simulate the concentrations of organic vapours and sulphuric acid inside the ABL – Part 1: Model description and initial evaluation

DEFF Research Database (Denmark)

Boy, M.; Sogachev, Andrey; Lauros, J.

2011-01-01

Chemistry in the atmospheric boundary layer (ABL) is controlled by complex processes of surface fluxes, flow, turbulent transport, and chemical reactions. We present a new model SOSA (model to simulate the concentration of organic vapours and sulphuric acid) and attempt to reconstruct the emissions...... in the surface layer we were able to get a reasonable description of turbulence and other quantities through the ABL. As a first application of the model, we present vertical profiles of organic compounds and discuss their relation to newly formed particles....

Temperature Effects on Stainless Steel 316L Corrosion in the Environment of Sulphuric Acid (H2SO4)

Science.gov (United States)

Ayu Arwati, I. G.; Herianto Majlan, Edy; Daud, Wan Ramli Wan; Shyuan, Loh Kee; Arifin, Khuzaimah Binti; Husaini, Teuku; Alfa, Sagir; Ashidiq, Fakhruddien

2018-03-01

In its application, metal is always in contact with its environment whether air, vapor, water, and other chemicals. During contact, chemical interactions emerge between metals and their respective environments such that the metal surface corrodes. This study aims to determine the corrosion rate of 316L stainless steel sulphuric acid environment (H2SO4) with weight loss and electrochemical methods. The corrosion rate (CR) is value of 316L stainless steel by weight loss method with sulfuric acid (H2SO4) with concentration of 0.5 M. The result obtained in conjunction with the increase of temperature the rate of erosion obtained appears to be larger, with a consecutive 3 hour the temperature of 50°C is 0.27 mg/cm2h, temperature 70°C 0.38 mg/cm2h, and temperature 90 °C 0.52 mg/cm2h. With the electrochemical method, the current value increases by using a C350 potentiostal tool. The higher the current, the longer the time the corrosion rate increases, where the current is at 90 °C with a 10-minute treatment time of 0.0014736 A. The 316L stainless steel in surface metal morphology is shown by using a Scanning Electron Microscope (SEM).

Volumetric properties of itaconic acid aqueous solutions

International Nuclear Information System (INIS)

Nisenbaum, Alexander; Apelblat, Alexander; Manzurola, Emanuel

2012-01-01

Highlights: ► Densities of itaconic acid aqueous solutions in a wide range of concentrations and temperatures. ► The apparent molar volumes and the cubic expansion coefficients. ► The derivatives of isobaric heat capacities with respect to pressure. ► Changes in the structure of water when itaconic acid is dissolved. - Abstract: Densities of itaconic acid aqueous solutions were measured at 5 K intervals from T = (278.15 to 343.15) K. From the determined densities, the apparent molar volumes, the cubic expansion coefficients and the second derivatives of volume with respect to temperature which are interrelated with the derivatives of isobaric heat capacities with respect to pressure were evaluated. These derivatives were qualitatively correlated with the changes in the structure of water when itaconic acid is dissolved in it.

Acidities of Water and Methanol in Aqueous Solution and DMSO

Science.gov (United States)

Gao, Daqing

2009-01-01

The relative acidities of water and methanol have been a nagging issue. In gas phase, methanol is more acidic than water by 36.0 kJ/mol; however, in aqueous solution, the acidities of methanol and water are almost identical. The acidity of an acid in solution is determined by both the intrinsic gas-phase ionization Gibbs energy and the solvent…

Process for extracting uranium from phosphoric acid solutions

International Nuclear Information System (INIS)

1977-01-01

The description is given of a method for extracting uranium from phosphoric acid solutions whereby the previously oxided acid is treated with an organic solvent constituted by a mixture of dialkylphosphoric acid and trialkylphosphine oxide in solution in a non-reactive inert solvent so as to obtain de-uraniated phosphoric acid and an organic extract constituted by the solvent containing most of the uranium. The uranium is then separated from the extract as uranyl ammonium tricarbonate by reaction with ammonia and ammonium carbonate and the extract de-uraniated at the extraction stage is recycled. The extract is treated in a re-extraction apparatus comprising not less than two stages. The extract to be treated is injected at the top of the first stage. At the bottom of the first stage, ammonia is introduced counter current as gas or as an aqueous solution whilst controlling the pH of the first stage so as to keep it to 8.0 or 8.5 and at the bottom of the last stage an ammonium carbonate aqueous solution is injected in a quantity representing 50 to 80% of the stoichiometric quantity required to neutralize the dialkylphosphoric acid contained in the solvent and transform the uranium into uranyl ammonium tricarbonate [fr

In situ structure solution of helical sulphur at 3 GPa and 400 C

Energy Technology Data Exchange (ETDEWEB)

Crichton, W.A.; Vaughan, G.B.M.; Mezouar, M. [European Synchrotron Radiation Facility (ESRF), 38 - Grenoble (France)

2001-07-01

The structure of a 2-chain helical form of sulphur with 9 atoms per unit-cell has been determined from powder synchrotron X-ray diffraction data obtained at 3 GPa and 400 C, using a combination of global optimization, simulated annealing and Rietveld refinement techniques. Final refinement of the structure in trigonal space group P3{sub 2}21 (no. 154) results in a = 7.0897(2) A, c = 4.30238(9) A and V = 187.282(10) A{sup 3}. There are two unique S sites per unit cell, the general S1 6c position with x = 0.7727(9), y = 0.3067(11) and z = 0.6105(12) and the S2 3b with x = 0.8755(8) A. Bond length and angle analysis shows S1-S1 = 2.070(4) A and S2-S2 = 2.096(7) A with an helical S1-S1-S1 divalent angle of 102.7(2) and 101.7(3) for S2-S2-S2. The 2 helices formed, contrary to other polymeric sulphur phases (principally, {psi}-S), are non-chiral and evidently have repeats along the (001) translation; that is one turn includes each of the 3 equivalent atoms about the 3{sub 2}-screw axis (S1 helix) and vertex (S2) of the cell. This phase, although temperature quenchable, is observed to back transform to a 4.04 A phase at pressures less than 0.5 GPa. It is likely that this phase represents the true form of the phase XII of Vezzoli and Walsh. (orig.)

Sulphur self–retention and sulphur dioxide capture with active calcium minerals in mineral–rich coals / Mchabe, D.

OpenAIRE

Mchabe, Dursman

2011-01-01

In order to provide information for the development of clean coal technology, the sulphur self–retention and sulphur dioxide capturing properties of minerals present in low grade coals was investigated. This study consisted of detailed mineral analyses of coal and ash samples using results obtained from QEMSCAN and separate retention (coal) and capture (ash) experiments with laboratory scale reactors. Typical South African coal samples were used in this study. The ash content v...

Behavior of copper in acidic sulfate solution: Comparison with acidic chloride

Energy Technology Data Exchange (ETDEWEB)

Tromans, D.; Silva, J.C. [Univ. of British Columbia, Vancouver, British Columbia (Canada). Dept. of Metals and Materials Engineering

1997-03-01

The anodic polarization behavior of copper in a 0.1 M sulfuric acid (H{sub 2}SO{sub 4}) + 1 M sodium sulfate (Na{sub 2}SO{sub 4}) solution (pH = 2.0) was studied at room temperature under quiescent and stirred conditions. The behavior was compared with aqueous equilibria via construction of a potential-vs-pH (E-pH) diagram for the copper-sulfate-water (Cu-SO{sub 4}{sup 2}-H{sub 2}O) system. Interpretation of the behavior was aided by comparison with aqueous equilibria and polarization studies of copper in a 0.2 M hydrochloric acid (HCl) + 1 M sodium chloride (NaCl) solution(pH = 0.8). The initial anodic dissolution region in the acidic sulfate solution exhibited Tafel behavior with a slope consistent with formation of cupric ions (Cu{sup 2+}) whose rate of formation was charge-transfer controlled. At higher potentials, limiting current density (i{sub L}) behavior was observed under E-pH conditions that were consistent with formation of a film of copper sulfate pentahydrate (CuSO{sub 4} {degree} 5H{sub 2}O). Comparison of experimental i{sub L} values with those predicted by mass transport-controlled processes, using estimates of the diffusion layer thickness obtained from the mass transfer-influenced region of apparent Tafel behavior in the acidic chloride solution, were in sufficient agreement to indicate i{sub L} was controlled by the rate of dissolution of the CuSO{sub 4} {degree} 5H{sub 2}O film via transport of Cu{sup 2+} from the film-electrolyte interface into the bulk solution.

Muon transfer to sulphur dioxide

International Nuclear Information System (INIS)

Mulhauser, F.; Schneuwly, H.

1993-01-01

A systematic study of muon capture and muon transfer has been performed in seven different H 2 + SO 2 gas mixtures. From the single-exponential time structure of the muonic sulphur x-rays, one determines the lifetime of the μp atoms under the given experimental conditions. The reduced muon transfer rates to the sulphur dioxide molecule, deduced from these lifetimes, all agree well with each other. The muonic oxygen time spectra show an additional structure as if μp atoms of another kind were present. Comparable time structures are observed in a D 2 + SO 2 mixture. (author)

Study of the sulfuric acid leaching and bacterial leaching of low grade uranium ore by orbital shaker experiment

International Nuclear Information System (INIS)

Li Guangyue; Liu Yulong; Wang Yongdong; Ding Dexin

2009-01-01

The sulphuric acid leaching and bacteria leaching by orbital shaker experiments were conducted for the low grade uranium ore from a uranium mine in Guangdong Province. The results show that, when the concentration of sulphuric acid and that of slurry were 30 g/L and 25%, respectively, the conditions were most favourable for sulphuric acid leaching and the rate of leaching reached 92.92%, that, when pH value was 1.5, inoculation amount, 10%, concentration of slurry, 10%, the conditions were most favourable for bacteria leaching and the rate of leaching reached 95.93%, that, compared with sulphuric acid leaching, bacteria leaching decreased sulphuric acid consumption by 17.2% and increased the rate of leaching by 3%, and that, under the most favourable conditions for suphuric acid leaching, if 1% natrium chlorate was added, the rate of leaching increased to 96.46%, but 10 kg of natrium chlorate was consumed for 1 ton of uranium ore. (authors)

Sulphate sulphur concentration in vegetable crops, soil and ground water in the region affected by the sulphur dioxide emission from Plock oil refinery (central Poland)

International Nuclear Information System (INIS)

Mikula, W.

1995-01-01

Research was carried out in 1984-1990 in the region affected by the sulphur dioxide emission from one of the greatest oil refineries in Europe (Plock, central Poland). The sulphate sulphur concentration in the vegetable crops (red beet, carrot, parsley, bean, cabbage and dill), the soil and in ground water was defined in selected allotment gardens of Plock city and in a household garden located in the rural area about 25 km from the town. The highest amount of sulphur was found in the vegetable crops cultivated in the garden situated in the closest vicinity of the refinery. Sulphate sulphur contents harmful for plants (above 0.50 per cent d.m.) were noted in cabbage and carrot leaves in almost all the gardens (except one). The soil in all examined gardens was characterised by high sulphate sulphur concentration, which considerably exceeds the maximum amount admissible for light soil in Poland, i.e. 0.004 per cent d.m. The sulphate sulphur concentration in ground water in all the gardens exceeded the highest permissible content in drinking water in Poland. The sulphate sulphur content in the soil and ground water was not significantly dependent on the garden's distance from the refinery. Generally, the above normal sulphate sulphur concentrations occurred quite universally in the examined region and they concerned all the considered environmental components (vegetable crops, soil, ground water) and all the gardens. 22 refs., 6 tabs

Availability and uptake of sulphur by mustard in three soils in Udaipur valley

International Nuclear Information System (INIS)

Kataria, S.K.; Shriniwas

1976-01-01

The differential behaviour of three soils (Bargaon, Bhatewar red and Bhatewar black) for availability of sulphur to mustard was studied in a greenhouse pot culture experiment using five doses of sulphur (0,20,40,80,120 ppm) applied as 35 S tagged ammonium sulphate. Application of sulphur significantly increased the dry matter of mustard over control, however, maximum dry matter was obtained when sulphur was applied at 40 ppm level, thereafter, any higher doses did not prove beneficial. Sulphur content in the plant tissue and percent of sulphur in the plant derived from fertilizer increased with successive doses of applied sulphur. (author)

SULPHUR AVAILABILITY IN BRAZILIAM SOILS: RESPONSE TO SULPHUR FERTILIZING IN PRESENCE AND AUSENCE OF LIMING DISPONIBILIDADE DE ENXOFRE EM SOLOS BRASILEIROS: RESPOSTA À ADUBAÇÃO SULFATADA NA PRESENÇA E AUSÊNCIA DE CALAGEM

Directory of Open Access Journals (Sweden)

Eurípedes Malavolta

2007-09-01

Full Text Available

A greenhouse experiment was carried out with surface samples of 12 soils from the States of São Paulo, Minas Gerais and Goiás (Brazil. Carbon (C content varied from 0.50 to 3.03%, sulphur from 0.0104 to 0.0319% and clay varied from 8 to 60%. Corn (Zea mays L. was grown in two successive croppings in presence of three rates of S (0, 20 and 40 ppm applied as gypsum, previously incubated in presence and absence of lime. Dry matter production did not show significant difference due to the two croppings of the soils; sulphur uptake, otherwise, was thoroughly lower in the second cropping, indicating the depletion of native and applied sulphur. Sandy soils have a lower supplying power of sulphur due to its effective small reserve. Clayey soils, moreover “cerrado” soils with higher carbon contents, possess greater croppings and sulphur uptake potentials, provided the soil acidity is neutralized. Liming, besides its role as soil acidity neutralizer and as calcium and magnesium supplier, showed positive interaction with sulphur and a synergistic effect on the depletion of soils native sulphur. The rates of sulphur which maximized dry matter yield and sulphur absorption varied in the range of 20 to 70 ppm, being the highest requirements found in clayey soils with no liming.

Conduziu-se um experimento em casa de vegetação com amostras superficiais de 12 solos, provenientes dos Estados de São Paulo, Minas Gerais e Goiás (Brasil, com teores de carbono variando entre 0,5 e 3,03%, de enxofre total entre 0,0104 e 0,319% e de argila entre 8 e 60%. Os solos foram submetidos a dois cultivos sucessivos com milho (Zea mays L., com os tratamentos: 12 solos, 3 doses de gesso (0, 20 e 40 ppm de S, previamente incubados na ausência e presença de calagem. A produção de matéria seca da parte a

Energetic and exergetic life cycle analysis to explain the hidden costs and effects of current sulphur utilisation

NARCIS (Netherlands)

Brehmer, B.; Sanders, J.P.M.

2007-01-01

Typically life cycle analyses of the fertiliser industry are based on averages of outdated technology. Sulphur is a major element, emerging as a primary nutrient on its own accord and as a feed for other fertiliser production, namely phosphoric acid. Recent developments sparked by governmental

Zirconium for nitric acid solutions

International Nuclear Information System (INIS)

Yau, T.L.

1984-01-01

The excellent corrosion resistance of zirconium in nitric acid has been known for over 30 years. Recently, there is an increasing interest in using zirconium for nitric acid services. Therefore, an extensive research effort has been carried out to achieve a better understanding of the corrosion properties of zirconium in nitric acid. Particular attention is paid to the effect of concentration, temperature, structure, solution impurities, and stress. Immersion, autoclave, U-bend, and constant strain-rate tests were used in this study. Results of this study indicate that the corrosion resistance of zirconium in nitric acid is little affected by changes in temperature and concentration, and the presence of common impurities such as seawater, sodium chloride, ferric chloride, iron, and stainless steel. Moreover, the presence of seawater, sodium chloride, ferric chloride, and stainless steel has little effect on the stress corrosion craking (SCC) susceptibility of zirconium in 70% nitric acid at room temperatures. However, zirconium could be attacked by fluoride-containing nitric acid and the vapors of chloride-containing nitric acid. Also, high sustained tensile stresses should be avoided when zirconium is used to handle 70% nitric acid at elevated temperatures or > 70% nitric acid

Effect of sulphur on the strengthening of a Zr-Nb alloy

International Nuclear Information System (INIS)

Chang, K.I.; Hong, S.I.

2008-01-01

The effect of sulphur on the strengthening and the thermally activated deformation of cold-worked Zr-1 Nb alloy was investigated. In the present study, the sulphur strengthening was observed even at room temperature unlike the previous study of Ferrer et al. The flow stress increased by 65 MPa at room temperature with the addition of sulphur as little as 20 ppm. With further increase of sulphur content up to 300 ppm, negligible change of the flow stress was observed. The additive strengthening behavior in which the entire stress-strain curve shift upward by the friction stress due to the addition of sulphur was observed in the Zr-Nb alloy of the present study. The activation volume decreased slightly (from 110b 3 to 80b 3 ) with the addition of 300 ppm sulphur at room temperature. The rate-controlling mechanism of the deformation can best be explained by the dislocation interaction mechanism in which the segregation of alloying elements such as oxygen and sulphur atoms affects the activation length of dislocations

Study of oxidation-reduction reactions of plutonium and neptunium in sulphuric-phosphoric acid media

International Nuclear Information System (INIS)

Moiseev, I.V.; Kuperman, A.Ya.; Borodina, N.N.; Galkina, V.N.; Vinokurov, V.A.

1976-01-01

Potentiostatic, coulometric, potentiometric, and amperometric methods have been used for determining the rate constants of disproportionation (ksub(d)) of plutonium(5) and neptunium (5) and normal real redox potentials (Esub(0)sup(p)) of the following ion pairs in sulphur-phosphoric-acid media: PuOsub(2)sup(2)sup(+) (PuO 2 + , Pu 4+ /Pu 3+ , NpO 2 2+ /NpO 2 + , NpO 2 2+ /Np 4+ , NpO 2 + /Np 4+ , and Fe 3+ /Fe 2+ . The regularities have been shown of changing ksub(d) and Esub(o)sup(p) as a function of H 2 SO 4 and H 3 PO 4 concentration. It has been established that for plutonium and neptunium a linear correlation is observed between lg ksub(d) and Esub(o)sup(p) of the ion pairs NpO 2 2+ /NpO 2 + , NpO 2 2 /Np 4+ , NpO 2 + /Np 4+ and PuO 2 2+ /PuO 2 + in a wide range of their values. The correlation coefficient is close to unity in all cases (no less than 0.96). The results of investigations have made it possible to recommend optimum compositions of background electrolytes for performing continuous amperostatic coulometric titration of Pusup((6)) and Npsup((6)) up to four valent state by electrogenerated ions of iron (2)

Organically bound sulphur in coal: A molecular approach

NARCIS (Netherlands)

Sinninghe Damsté, J.S.; Leeuw, J.W. de

1992-01-01

A critical review of literature concerning the molecular characterization of low and high molecular weight organosulphur constitutents present in coal as well as a detailed analysis of organic sulphur compounds present in flash evaporates and pyrolysates of a suite of coals ranging in sulphur

A Novel Method for Fabricating Double Layers Porous Anodic Alumina in Phosphoric/Oxalic Acid Solution and Oxalic Acid Solution

Directory of Open Access Journals (Sweden)

Yanfang Xu

2016-01-01

Full Text Available A novel method for fabricating ordered double layers porous anodic alumina (DL-PAA with controllable nanopore size was presented. Highly ordered large pore layer with interpore distance of 480 nm was fabricated in phosphoric acid solution with oxalic acid addition at the potential of 195 V and the small pore layer was fabricated in oxalic acid solution at the potential from 60 to 100 V. Experimental results show that the thickness of large pore layer is linearly correlative with anodizing time, and pore diameter is linearly correlative with pore widening time. When the anodizing potential in oxalic acid solution was adjusted from 60 to 100 V, the small pore layers with continuously tunable interpore distance from 142 to 241 nm and pore density from 1.94×109 to 4.89×109 cm−2 were obtained. And the interpore distance and the pore density of small pore layers are closely correlative with the anodizing potential. The fabricated DL-PAA templates can be widely utilized for fabrication of ordered nanomaterials, such as superhydrophobic or gecko-inspired adhesive materials and metal or semiconductor nanowires.

Amino acid composition of some Mexican foods.

Science.gov (United States)

Morales de León, Josefina; Camacho, M Elena; Bourges, Héctor

2005-06-01

Knowledge of the amino acid composition of foods is essential to calculate their chemical score, which is used to predict protein quality of foods and diets. Though amino acid composition of many foods is reasonably well established, better knowledge is needed on native foods consumed in different regions and countries. This paper presents the amino acid composition of different presentations of raw and processed foods produced and consumed in Mexico. The amino acid composition was determined using Beckman amino acid analyzers (models 116 and 6300). Tryptophan was determined using the Spies and Chambers method. Of the different foods analyzed, some comments are made on native or basic foods in Mexico: Spirulin, where lysine is the limiting amino acid, with a chemical score of 67%, is a good source of tryptophan (1.16g/16 gN); amaranth contains high levels of sulphur amino acids (4.09 to 5.34 g/16gN), with a protein content of 15 g/100g; and pulque, a Pre-Hispanic beverage that contains high levels of tryptophan (2.58 g/16 gN) and sulphur amino acids (2.72 g/16 gN). Finally, insects are good sources of sulphur amino acids and lysine.

In-situ degradation of sulphur mustard using (1R)-(-)-(camphorylsulphonyl) oxaziridine impregnated adsorbents

Energy Technology Data Exchange (ETDEWEB)

Sharma, Abha, E-mail: abha_052002@yahoo.co.in [Industrial Toxicology Research Centre, Mahatam Gandhi Marg, Lucknow, UP (India); Saxena, Amit; Singh, Beer [Defence Research and Development Establishment, Jhansi Road, Gwalior, MP (India)

2009-12-30

Bis-2-chloroethyl sulphide (sulphur mustard or HD) is an extremely toxic and persistent chemical warfare agent. For in-situ degradation of HD and its analogues (simulants), i.e., dibutyl sulphide (DBS) and ethyl 2-hydroxyethyl sulphide (HEES), different adsorbents systems loaded with (1R)-(-)-(camphorylsulphonyl) oxaziridine were prepared. Solution of sulphur mustard and its simulants was prepared in carbon tetrachloride and taken for uniform adsorption on the impregnated systems using incipient volume. Degradation kinetics monitored by GC/FID were found to be first-order. The half-life of degradation reactions for simulants was obtained in less than 30 and for HD in 120 min. From the studied kinetics it was observed that reaction was very rapid with simulants and decreased rate was found for HD. The order of reactivity of MgO/Oxa system for HD and simulants was found to be DBS > HEES > HD. Reaction products of the oxidation reaction of simulants and HD on adsorbents were extracted in dichloromethane and analysed by GC-MS. The products were found to be non-toxic sulphoxide. The objective of the study is to develop a reactive adsorbent for in-situ degradation of sulphur mustard which could be used in nuclear biological and chemical (NBC) filtration systems.

Investigations on the oxidation of nitric acid plutonium solutions with ozone

International Nuclear Information System (INIS)

Boehm, M.

1983-01-01

The reaction of ozone with nitric acid Pu solutions was studied as a function of reaction time, acid concentration and Pu concentration. Strong nitric acid Pu solutions are important in nuclear fuel element production and reprocessing. The Pu must be converted into hexavalent Pu before precipitation from the homogeneous solution together with uranium-IV, ammonia and CO 2 in the form of ammonium uranyl/plutonyl carbonate (AUPuC). Formation of a solid phase during ozonation was observed for the first time. The proneness to solidification increases with incrasing plutonium concentrations and with decreasing acid concentrations. If the formation of a solid phase during ozonation of nitric acid Pu solutions cannot be prevented, the PU-IV oxidation process described is unsuitable for industrial purposes as Pu solutions in industrial processes have much higher concentrations than the solutions used in the present investigation. (orig./EF) [de

Biological parameters in technogenic soils of a former sulphur mine

Science.gov (United States)

Siwik-Ziomek, Anetta; Brzezińska, Małgorzata; Lemanowicz, Joanna; Koper, Jan; Szarlip, Paweł

2018-04-01

This study was conducted on the soils originating from a reclamation area of the former sulphur mine in Tarnobrzeg, Poland. Soil was sampled 16 years after the completion of mining works with the open-pit method at Machów, as well as 7 years after sulphur mining via the `smelting' method in the Jeziórko mine was abandoned. Several biological parameters were examined: soil respiration, soil microbial biomass and the activity of rhodanese and arylsulphatase enzymes taking part in sulphur transformation within the site's soils. The soils showed a high total sulphur and sulphates content. The SO42- constituted a large fraction of total sulphur, in some cases, exceeding 80% or even 95% of total sulphur. The soil pH decreased due to the degrading effects of sulphur mining. In the soils studied from the locations with the lowest soil pH value, no activity of arylsulphatase was reported and the activity of rhodanese was lowest. The highest soil respiration values were recorded from the 0-5 cm layer in the areas covered with forest vegetation. A high soil respiration value at the waste heap at Machów wherein a very high concentration of Stot and SO42- was observed can be due to the ability of fungi to produce hyphal strands and to survive unfavourable conditions.

Waste acid/metal solution reduction and recovery by vacuum distillation

International Nuclear Information System (INIS)

Jones, E.O.; Wilcox, W.A.; Johnson, N.T.; Bowdish, F.W.

1995-01-01

Processes involving distillation under reduced pressure were developed at the Pacific Northwest Laboratory several years ago to recover spent acid solutions generated during the manufacture of nuclear fuel for the N-Reactor at the Hanford site. Following construction and testing of a pilot-plant, the technology was licensed to Viatec Recovery Systems, Inc. for commercialization. The technology developed included specialized distillation and rectification of volatile acids, removal of water and/or volatile acid from sulfuric acid, and precipitation of salts. A key feature of the Waste Acid Detoxification and Reclamation (WADR) technology is the development and use of advanced thermoplastic and fluoropolymer materials of construction in all critical process equipment. The technology was then expanded to include crystallization to recover metal salts for possible reuse. Economic and environmental advantages of the procedures include recovery of acids for reuse, simplification or elimination of the disposal of waste solutions, and possible recovery of metals. Industries expected to benefit from such applications include galvanizing, electroplating, sand leaching and any where metals are cleaned in acid solutions. Currently a modular system has been assembled for recovery of several different spent acid solutions

A new technology aimed at re-establishing a global sulphur supply/demand balance

International Nuclear Information System (INIS)

Slavens, A.F.; Jorgensen, C.; Ogg, D.

2009-01-01

The world's sulphur supply is mainly determined by involuntary production of elemental sulphur during the processing of oil and gas. As a result, sulphur supply is decoupled from demand, resulting in an imbalance between the two. For almost two decades, sulphur supply has exceeded demand, which has raised significant concerns for oil and gas producers such as where to store all of the excess sulphur, and how to transport a low-value commodity to market in an economically attractive fashion. Black and Veatch is involved in the development of a new technology called sulphur to energy process (STEP TM ) which has the potential to assist in balancing global sulphur supply and demand, as well as affording other benefits such as low-emission energy production. This paper presented the potential merits of the STEP as a means to reestablish a global sulphur supply/demand balance for the world trading market. It explored the other potential benefits that may result from the use of this new technology and compared STEP to other technologies and operating schemes that regulate sulphur supply. It was concluded that STEP has the potential to allow the processor to produce elemental sulphur when demand is high, or to provide safe and ecological disposal when demand is low, with the added benefits of energy recovery from the sulphur combustion process, and sour gas reservoir sweetening over time as sulphur dioxide reacts with hydrogen sulphide present in the reservoir. 13 refs., 3 tabs., 22 figs

Corrosion control of vanadium in aqueous solutions by amino acids

International Nuclear Information System (INIS)

El-Rabiee, M.M.; Helal, N.H.; El-Hafez, Gh.M. Abd; Badawy, W.A.

2008-01-01

The electrochemical behavior of vanadium in amino acid free and amino acid containing aqueous solutions of different pH was studied using open-circuit potential measurements, polarization techniques and electrochemical impedance spectroscopy (EIS). The corrosion current density, i corr , the corrosion potential, E corr and the corrosion resistance, R corr , were calculated. A group of amino acids, namely, glycine, alanine, valine, histidine, glutamic and cysteine has been investigated as environmentally safe inhibitors. The effect of Cl - on the corrosion inhibition efficiency especially in acid solutions was investigated. In neutral and basic solutions, the presence of amino acids increases the corrosion resistance of the metal. The electrochemical behavior of V before and after the corrosion inhibition process has shown that some amino acids like glutamic acid and histidine have promising corrosion inhibition efficiency at low concentration (≅25 mM). The inhibition efficiency (η) was found to depend on the structure of the amino acid and the constituents of the corrosive medium. The corrosion inhibition process is based on the adsorption of the amino acid molecules on the metal surface and the adsorption process follows the Freundlich isotherm. The adsorption free energy for valine on V in acidic solutions was found to be -9.4 kJ/mol which reveals strong physical adsorption of the amino acid molecules on the vanadium surface

Vapor-liquid equilibria for nitric acid-water and plutonium nitrate-nitric acid-water solutions

International Nuclear Information System (INIS)

Maimoni, A.

1980-01-01

The liquid-vapor equilibrium data for nitric acid and nitric acid-plutnonium nitrate-water solutions were examined to develop correlations covering the range of conditions encountered in nuclear fuel reprocessing. The scanty available data for plutonium nitrate solutions are of poor quality but allow an order of magnitude estimate to be made. A formal thermodynamic analysis was attempted initially but was not successful due to the poor quality of the data as well as the complex chemical equilibria involved in the nitric acid and in the plutonium nitrate solutions. Thus, while there was no difficulty in correlating activity coefficients for nitric acid solutions over relatively narrow temperature ranges, attempts to extend the correlations over the range 25 0 C to the boiling point were not successful. The available data were then analyzed using empirical correlations from which normal boiling points and relative volatilities can be obtained over the concentration ranges 0 to 700 g/l Pu, 0 to 13 M nitric acid. Activity coefficients are required, however, if estimates of individual component vapor pressures are needed. The required ternary activity coefficients can be approximated from the correlations

SULPHUR CONTAINING LICKS AND THEIR EFFECT ON THE ...

African Journals Online (AJOL)

amounts of sulphur, there are some of particular importance such as the vitamins thiamine and biotin. Sulphur is also ingested in the inorganic sulphide and sulphate forms, fractions of which are utilized in metabolic processes, whereas substantial portions are also excreted. It has been determined that thiol cornpounds.

Role of sulphur in rice production

International Nuclear Information System (INIS)

Sachdev, Pamila; Sachdev, M.S.

2002-01-01

Sulphur is an essential plant nutrient growing in international importance. Rice farmers usually apply nitrogen, phosphorus and potassium at high rates to the crop. Whenever there is an imbalance between off take and input of nutrients, it may lead to a decline in soil fertility and increase incidence of deficiencies of certain plant nutrients especially sulphur and zinc. On the basis of available information, nutritional requirement, uptake values, crop response and measures to overcome S deficiency are some of the aspects critically dealt with

The recovery of uranium, gold and sulphur from residues from South African mines

International Nuclear Information System (INIS)

Toens, P.D.

1978-10-01

The slimes dams resulting from the operations of gold and gold/uranium mines situated within the Witwatersrand Basin contain low concentrations of gold, uranium and pyrite. As a result of a marked increase in the prices of both gold and uranium in recent years, two schemes involving the recovery of these minerals also the manufacture of sulphuric acid as a by-product are operating profitably. Further schemes are under investigation [af

Levels of cystathionine gamma lyase production by Geotrichum candidum in synthetic media and correlation with the presence of sulphur flavours in cheese.

Science.gov (United States)

Gente, Stéphanie; La Carbona, Stéphanie; Guéguen, Micheline

2007-03-10

Geotrichum candidum is a cheese-ripening agent with the potential to produce sulphur flavour compounds in soft cheeses. We aimed to develop an alternative test for predicting the aromatic (sulphur flavours) potential of G. candidum strains in soft cheese. Twelve strains of G. candidum with different levels of demethiolase activity (determined by a chemical method) in YEL-met (yeast extract, lactate methionine) medium were studied. We investigated cgl (cystathionine gamma lyase) gene expression after culture in three media - YEL-met, casamino acid and curd media - and then carried out sensory analysis on a Camembert cheese matrix. We found no correlation between demethiolase activity in vitro and cgl gene expression. Sensory analysis (detection of sulphur flavours) identified different aromatic profiles linked to cgl expression, but not to demethiolase activity. The RT-PCR technique described here is potentially useful for predicting the tendency of a given strain of G. candidum to develop sulphur flavours in cheese matrix. This is the first demonstration that an in vitro molecular approach could be used as a predictive test for evaluating the potential of G. candidum strains to generate sulphur compounds in situ (Camembert cheese matrix).

Polarography of hexavalent molybdenum in hypophosphorous acid solutions

International Nuclear Information System (INIS)

Hassan, A.; El-Shatory, S.A.; Azab, H.A.

1988-01-01

The polarographic behaviour and determination of Mo(6) in hypophosphorous acid solutions of concentrations varying from 0,1 to 5,0 moll -1 and T = 25±0,1 0 C have been investigated. It was shown that reduction of MoO 4 2- takes place along a single or two waves depending upon the acid concentration. Microcoulometric experiments have been performed at the limiting region of the different waves obtained at different acid concentrations. A scheme for the mechanism of reduction occuring at the DME has been deduced. A method for analytical determination of Mo(6) on both the micro- and macro-scales in hypophosphorous acid solutions has been reported. Analysis of a binary mixture Mo(6)/Cd(2) and a tertiary mixture Mo(6)/Cd(2)/Zn(2) in moll -1 hypophosphorous acid has been investigated. (Author)

The role of acid anion on the inhibition of the acidic corrosion of steel by lupine extract

Energy Technology Data Exchange (ETDEWEB)

Abdel-Gaber, A.M. [Chemistry Department, Faculty of Science, Alexandria University, Ibrahimia, P.O. Box 426, Alexandria 21321 (Egypt)], E-mail: ashrafmoustafa@yahoo.com; Abd-El-Nabey, B.A.; Saadawy, M. [Chemistry Department, Faculty of Science, Alexandria University, Ibrahimia, P.O. Box 426, Alexandria 21321 (Egypt)

2009-05-15

The inhibitive effect of lupine (Lupinous albus L.) extract on the corrosion of steel in aqueous solution of 1 M sulphuric and 2 M hydrochloric acids was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. Potentiodynamic polarization curves indicated that the lupine extract acts as a mixed-type inhibitor. EIS measurements showed that the dissolution process is under activation control. The inhibition efficiency of the extract obtained from impedance and polarization measurements was in a good agreement and was found to increase with increasing concentration of the extract. The obtained results showed that, the lupine extract could serve as an effective inhibitor for the corrosion of steel in acid media and the extract was more effective in case of hydrochloric acid. Theoretical fitting of the corrosion data to the kinetic-thermodynamic model was tested to show the nature of adsorption.

Recovery of alumina from khushab bauxite by leaching with sulphuric acid and removal of iron impurity by ethanol

International Nuclear Information System (INIS)

Tariq, M.; Iqbal, M.M.; Shafiq, M.; Aziz, A.

2014-01-01

Bauxite is heterogeneous material principally composed of aluminum oxide minerals and found in all continents. It is being used in chemical, cement, refractory, abrasive, fertilizer, steel and other industries. In order to extract the alumina, the calcined samples of bauxite of Khushab area were ground to -710 meum. Sulphuric acid of purity 40% was used as leaching agent and slurry of pulp density 14% was prepared by dissolving 60 ml acid in 20 gm sample. The leaching was carried out at 90 degree C for 2 hours. The iron impurity was removed by ethanol of purity 68%. The drying, dehydration and desulphurization temperatures were kept 105 degree C, 450 degree C and 850 degree C respectively in all the stages of the process. Alumina recoveries from four samples of Sultan Mehdhi, Chamil More, Niaz Mine and Nadi locations were 20.8%, 9.81%, 15.47% and 7.78% respectively. Iron was almost completely removed as the analysis shows that the Fe/sub 2/O/sub 3/ removal was from 97.8% to 99.6%. It is concluded that leaching efficiency was quite encouraging except Nadi ore sample. However the iron free alumina recoveries were low as the analysis of Fe/sub 2/O/sub 3/ processed residue shows that it contains 72.72% to 92.94% of leached alumina in all the four experiments. (author)

Process for the removal of radium from acidic solutions containing same

Science.gov (United States)

Scheitlin, F.M.

The invention is a process for the removal of radium from acidic aqueous solutions. In one aspect, the invention is a process for removing radium from an inorganic-acid solution. The process comprises contacting the solution with coal fly ash to effect adsorption of the radium on the ash. The radium-containing ash then is separated from the solution. The process is simple, comparatively inexpensive, and efficient. High radium-distribution coefficients are obtained even at room temperature. Coal fly ash is an inexpensive, acid-resistant, high-surface-area material which is available in large quantities throughout the United States. The invention is applicable, for example, to the recovery of /sup 226/Ra from nitric acid solutions which have been used to leach radium from uranium-mill tailings.

Mathematical modelling of demineralisation of high sulphur coal by bioleaching

Energy Technology Data Exchange (ETDEWEB)

Weerasekara, N.S.; Frutos, F.J.G.; Cara, J.; Lockwood, F.C. [University of London Imperial College of Science Technology & Medicine, London (United Kingdom)

2008-02-15

During coal combustion various toxic compounds are generated from its sulphur content. Their environmental impacts are considered to be very important. While there are various conventional preparation methods to remove the sulphur in the fuel, recent work reveals that newly-isolated micro-organisms, naturally present in coal, have the ability to reduce its sulphur content. The removal of sulphur using biological leaching involving acidophilic iron oxidising bacteria like Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans are examined and a computational technique based on computational fluid dynamics is developed to model the biological leaching of sulphur from coal. The model was validated against a pack-column experiment carried out for iron separation during 60 days. The mathematical model predicted iron separation over time is similar to experimental measurements, with an average difference of 5.5%. According to the experimental results, there was an overall reduction of 33% of pyrite, whereas the model prediction was 32%. The model results shows overall good agreement with pack-column experimental data.

Treatment for GaSb surfaces using a sulphur blended (NH4)2S/(NH4)2SO4 solution

International Nuclear Information System (INIS)

Murape, D.M.; Eassa, N.; Neethling, J.H.; Betz, R.; Coetsee, E.; Swart, H.C.; Botha, J.R.; Venter, A.

2012-01-01

A sulphur based chemical, [(NH 4 ) 2 S/(NH 4 ) 2 SO 4 ] to which S has been added, not previously reported for the treatment of (1 0 0) n-GaSb surfaces, is introduced and benchmarked against the commonly used passivants Na 2 S·9H 2 O and (NH 4 ) 2 S. The surfaces of the treated material were studied by scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). It has been found that the native oxides present on the GaSb surface are more effectively removed when treated with ([(NH 4 ) 2 S/(NH 4 ) 2 SO 4 ] + S) than with (NH 4 ) 2 S or Na 2 S·9H 2 O, as evidenced by the ratio of the O 506eV to Sb 457eV AES peaks. XPS results reveal that Sb 2 S 3 /Sb 2 S 5 “replaces” Sb 2 O 3 /Sb 2 O 5 , suggesting that sulphur atoms substitute oxygen atoms in Sb 2 O 3 /Sb 2 O 5 to form Sb-S. It seems sulphurization only partially removes Ga 2 O 3 . Treatment with ([(NH 4 ) 2 S/(NH 4 ) 2 SO 4 ] + S) also results in a noteworthy improvement in the current-voltage (I-V) characteristics of Au/n-GaSb Schottky contacts compared to those fabricated on as-received material.

Estimation of solubility of organo-phosphorus extractants by P determination using molybdovanadophosphoric acid method

International Nuclear Information System (INIS)

Gill, J.S.; Kotekar, M.K.; Singh, H.

2005-01-01

Solvent extraction processes have been found to be suitable for uranium recovery from phosphoric acid. Various extractants like di-2-ethyl hexylphosphoric acid (D2EHPA), di-nonylphenyl phosphoric acid (DNPPA) and synergistic agents like tri-butyl phosphate (TBP), tri-octyl phosphine oxide (TOPO) have been used in liquid-liquid extraction of uranium from phosphoric acid. Contents of these organo-phosphorus compounds in aqueous raffinates need estimation for process requirements. Solubility of Tri-butyl phosphate (TBP) and Di-2-ethylhexyl phosphoric acid (D2EHPA) extractants have been determined in different media of water, oxalic acid (0.6M) and sulphuric acid (3.75M) solutions. These compounds were estimated by determining their phosphorus (P) contents employing molybdovanadophosphoric acid method, after digesting and solubalizing them in nitric and perchloric acid. (author)

Recovery of Tin and Nitric Acid from Spent Solder Stripping Solutions

International Nuclear Information System (INIS)

Ahn, Jae-Woo; Ryu, Seong-Hyung; Kim, Tae-young

2015-01-01

Spent solder-stripping solutions containing tin, copper, iron, and lead in nitric acid solution, are by-products of the manufacture of printed-circuit boards. The recovery of these metals and the nitric acid, for re-use has economic and environmental benefits. In the spent solder-stripping solution, a systematic method to determine a suitable process for recovery of valuable metals and nitric acid was developed. Initially, more than 90% of the tin was successfully recovered as high-purity SnO 2 by thermal precipitation at 80 ℃ for 3 hours. About 94% of the nitric acid was regenerated effectively from the spent solutions by diffusion dialysis, after which there remained copper, iron, and lead in solution. Leakage of tin through the anion-exchange membrane was the lowest (0.026%), whereas Pb-leakage was highest (4.26%). The concentration of the regenerated nitric acid was about 5.1 N.

Gamma radiolysis of aqueous solution of ascorbic acid

International Nuclear Information System (INIS)

Loyola V, V.M.; Azamer B, J.A.; Laviada C, A.; Luna V, P.

1977-01-01

A preliminary study of the gamma radiolysis of a 1.13 x 10 -4 Maqueous solution of ascorbic acid is presented. It was found that dehydroascorbic acid was the principal product at doses of about 75 Krad. An increase in the dehydroascorbic acid concentration rangins from 5 to 40% was obtained, these values depend mainly on the initial ascorbic acid concentration. (author)

CO2 Capture from Flue Gas using Amino Acid Salt Solutions

DEFF Research Database (Denmark)

Lerche, Benedicte Mai; Stenby, Erling Halfdan; Thomsen, Kaj

2009-01-01

difficult. Amino acid salt solutions have emerged as an alternative to the alkanolamine solutions. A number of advantages make amino acid salt solutions attractive solvents for CO2 capture from flue gas. In the present study CO2 absorption in aqueous solutions of 0.5 M potassium glycinate and 0.5 M...

Sulphur Extraction at Bryan Mound

Energy Technology Data Exchange (ETDEWEB)

Kirby, Carolyn L [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lord, Anna C. Snider [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-08-01

The Bryan Mound caprock was subjected to extens ive sulphur mining prior to the development of the Strategic Petroleum Reserve. Undoubtedl y, the mining has modified the caprock integrity. Cavern wells at Bryan Mound have been subject to a host of well integr ity concerns with many likely compromised by the cavernous capro ck, surrounding corrosive environment (H ₂ SO ₄ ), and associated elevated residual temperatures al l of which are a product of the mining activities. The intent of this study was to understand the sulphur mining process and how the mining has affected the stability of the caprock and how the compromised caprock has influenced the integrity of the cavern wells. After an extensiv e search to collect pert inent information through state agencies, literature sear ches, and the Sandia SPR librar y, a better understanding of the caprock can be inferred from the knowledge gaine d. Specifically, the discovery of the original ore reserve map goes a long way towards modeling caprock stability. In addition the gained knowledge of sulphur mining - subs idence, superheated corrosive wa ters, and caprock collapse - helps to better predict the post mi ning effects on wellbore integrity. This page intentionally left blank

Sulphur isotope measurements on sulphates from Antarctic atmospheric precipitations, lake waters and salt efflorescences: a contribution to the study of the natural sulphur cycle

International Nuclear Information System (INIS)

Wand, U.; Maass, I.; Haendel, D.

1987-01-01

Sulphur isotope analyses are an important tool for the study of the natural sulphur cycle. However, on the northern hemisphere such studies particularly of the atmospheric component of the cycle are seriously hampered and in many regions practically impossible because of the high emission rate of anthropogenic sulphur. Only in remote areas of the world such as the Antarctic 34 S analyses can be used with success to identify the various natural sulphur sources (marine, biogenic and volcanic sources). We report here preliminary results of 34 S isotope measurements on sulphates from recent atmospheric precipitations (snow), lake waters and salt efflorescences sampled in the Schirmacher Oasis and the Wohlthat Massif, central Queen Maud Land, East Antarctica. Except for 4 efflorescence samples the sulphates investigated in this work are enriched in 34 S relative to the meteoritic sulphur standard (CDT). On an average the sulphates of our study area are isotopically lighter than those from the McMurdo region, South Victoria land. The latter region is characterized by the predominance of salts of marine origin. (author)

Water solubilization and the dielectric permeability of isomolar solutions of oleic acid and triethanolamine soap of oleic acid

Energy Technology Data Exchange (ETDEWEB)

Demchenko, P.A.; Novitskaya, L.D.

The investigation of the dependence of water solubilization on the dielectric permeability of isomolar solutions of oleic acid and triethanolamine soap of oleic acid in benzene has shown that at certain acid additions, the solubilization effect can increase almost 6 times, as compared to the soap solution without acid additions. In some cases, electron donor-acceptor complexes are formed, which are more polar than the original components. This leads to a change in the molecular-disperse and micellar part of solution and affects significantly the structure and properties of micellar hydrocarbon solutions of surfactants.

Reaction of nitrous acid with U(IV) and nitric acid in 30% TBP-kerosene solution

International Nuclear Information System (INIS)

Xu Xiangrong; Hu Jingxin; Huang Huaian; Qiu Xiaoxi

1990-01-01

Reaction of nitrous acid with U(IV) and nitric acid in 30% TBP-kerosene solution is investigated, the rate equations of oxidation of U(IV) by nitrous acid and that of nitrous acid reacting with nitric acid are obtained

Predicting nitrogen and acidity effects on long-term dynamics of dissolved organic matter

OpenAIRE

Rowe, E.C.; Tipping, E.; Posch, M.; Oulehle, Filip; Cooper, D.M.; Jones, T.G.; Burden, A.; Hall, J.; Evans, C.D.

2014-01-01

Increases in dissolved organic carbon (DOC) fluxes may relate to changes in sulphur and nitrogen pollution. We integrated existing models of vegetation growth and soil organic matter turnover, acid-base dynamics, and organic matter mobility, to form the ‘MADOC’ model. After calibrating parameters governing interactions between pH and DOC dissolution using control treatments on two field experiments, MADOC reproduced responses of pH and DOC to additions of acidifying and alkalising solutions. ...

Selective extraction of metals from acidic uranium(VI) solutions using neo-tridecano-hydroxamic acid

International Nuclear Information System (INIS)

Bardoncelli, F.; Grossi, G.

1975-01-01

According to this invention neo-alkyl-hydroxamic acids are employed as ion-exchanging agents in processes for liquid-liquid extraction with the aim of separating, purifying dissolved metals and of converting a metal salt solution into a solution of a salt of the same metal but with different anion. In particular it is an objective of this invention to provide a method whereby a molecular pure uranium solution is obtained by selective extraction from a uranium solution delivered by irradiated fuel reprocessing plants and containing plutonium, fission products and other unwanted metals, in which method neo-tridecane-hydroxamic acid is employed as ion exchanger. (Official Gazette)

Contribution to the study of the electrochemical behaviour of titanium and of its industrial shores in sulphuric environment. Characteristics of their resistance to pitting corrosion in neutral and acid halogenous environment

International Nuclear Information System (INIS)

Petit, Jacques-Alain

1975-01-01

After a presentation of the general metallurgical, physical, and corrosion resistance characteristics of titanium and of its alloys, this research thesis presents the experimental means, discusses the influence of experimental conditions on the assessment of the electrochemical behaviour of titanium and of its alloys. It reports an investigation of the cathodic behaviour of non-alloyed titanium and notably the hydrogen release kinetics in a concentrated acid environment. It discusses the influence of alloy composition on their cathodic behaviour, addresses the anodic behaviour of titanium and of its alloys in sulphuric environment, and the pitting corrosion of titanium and of its alloys in an acid and neutral halogenous environment [fr

Being green on sulphur: Targets, measures and side-effects

DEFF Research Database (Denmark)

Kontovas, Christos A.; Panagakos, George; Psaraftis, Harilaos N.

2016-01-01

to sea to reduce congestion, and might ultimately (under certain circumstances) increase the overall level of CO2 emissions along the entire supply chain. The purpose of this chapter is to investigate the potential effect of sulphur regulations on the share of cargo transported by the waterborne mode vis......Green House Gas (GHG) emissions are not the only emissions of concern to the international transport community. SOx emissions are non-GHG emissions that are caused by the presence of sulphur in the fuel. As the maximum percentage of sulphur in automotive and aviation fuels is strictly regulated...

Distribution and isotopic abundance of sulphur in recent marine sediments off southern California

Energy Technology Data Exchange (ETDEWEB)

Kaplan, I R; Emergy, K O; Rittenberg, S C

1963-01-01

Analyses of sulphur compounds in basin sediments off southern California indicate that elemental sulphur, free sulphide, hydrotroilite, organic sulphur, sulphate and pyrite are present in quantities that vary with environment and depth in the sediments. Pyrite is generally the most abundant form, occurring in oxidizing as well as in reducing sediments and often constituting 90% of total sulphur. A material balance indicates that the total sulphur content is far in excess of the sulphate-sulphur initially trapped in the interstitial water. This evidence, together with failure to detect significant alternate sources, suggests that sulphate-sulphur is extracted from the overlying sea water at the sediment-water interface. Isotope measurements confirm many of the conclusions suggested by the quantitative chemical analyses. The show that biological sulphate reduction is the single most important process in the sulphur cycle. The sulphide released is converted to hydrotrolite and then to pyrite. Elemental and organic sulphur appear to be continually forming and reacting in the sediment column. The organic sulphur released from decaying organic matter apparently plays only a small role in the sulphur economy. Enrichment in S/sup 32/ ranging from 9 to 62% was measured in pyrite fragments, a spread similar to that previously observed in ancient sediments. Data from field and laboratory experiments were combined to determine rate of sulphate reduction, number of sulphate reducing bacteria and the amount of organic matter decomposed during sulphate reduction in the sediment, as well as rate of renewal of water in the basins. The results suggest that the methods used may have many applications for elucidating in situ rate processes.

Reaction Kinetics of Monomethylhydrazine With Nitrous Acid in Perchloric Acid Solution

International Nuclear Information System (INIS)

Wei Yan; Wang Hui; Pan Yongjun; Cong Haifeng; Jiao Haiyang; Jia Yongfen; Zheng Weifang

2009-01-01

The oxidation of monomethylhydrazine (MMH) by nitrous acid was researched in perchloric acid solution with spectrophotometry. The rate equation has been determined as follows: -dc (HNO 2 ) /dt= kc (H + ) 0.9 c (MMH) 1.1 c (HNO 2 ), k is (46.0 ± 2.7) L 2 / (mol 2 · s) with the initial perchlorate concentration of 0.50 mol/L at the temperature of 4.5 degree C. The corresponding activation energy of the reaction is (42.4 ± 0.1) kJ/mol. The results indicate that oxidation of mono-methylhydrazine (MMH) by nitrous acid is fast. The higher concentration of MMH can accelerate the reduction process of nitrous acid. Higher acidity can also speed up the reduction of nitrous acid. (authors)

Online Automatic Titration of Chromic Acid in Chromium Plating Solutions and Phosphoric and Sulfuric Acids in Electropolishing Solutions

National Research Council Canada - National Science Library

Sopok, Samuel

1991-01-01

.... The analytical chemistry literature lacks an adequate online automatic titration method for the monitoring of chromic acid in chromium plating solutions and the monitoring of phosphoric and sulfuric...

Vibrational studies in aqueous solutions. Part II. The acid oxalate ion and oxalic acid

Science.gov (United States)

Shippey, T. A.

1980-08-01

Assignments for oxalic acid in solution are re-examined. A detailed assignment of the IR and Raman spectra of the acid oxalate ion is presented for the first time. Raman spectroscopy is used to study the first ionization of oxalic acid.

Determination of free acid in plutonium (IV) solutions - thermometrically, potentiometrically

International Nuclear Information System (INIS)

Williams, T.L.; Tucker, G.M.; Huff, G.A.; Jordan, L.G.

1981-09-01

The thermometric titration technique was found to offer certain advantages over potentiometry in the determination of free acid in Pu(IV) solutions. The thermometric technique was applied to the determination of free acid in plutonium nitrate solutions using potassium fluoride to suppress the hydrolytic interference of plutonium(IV). The results indicate that 0.2 to 2.0 milliequivalents of free acid can be determined with acceptable bias and precision in solutions containing up to 30 milligrams of plutonium. In contrast, neither the thermometric nor the potentiometric technique was suitable for samples containing more than eight milligrams of plutonium complexed with potassium oxalate

Pyrotechnic countermeasures: IV. Radiometric performance of a sulphur-based Flare composition

Energy Technology Data Exchange (ETDEWEB)

Koch, Ernst-Christian [NATO Munitions Safety Information Analysis Center (MSIAC), Brussels (Belgium)

2008-10-15

Radiometric performance of a sulphur-based flare composition has been investigated. Composition comprising sulphur, potassium perchlorate and antimony sulphide has acceptable band ratio but an order of magnitude weaker spectral efficiency than typical carbon-based compositions. The use of other sulphur compounds with potential for increased performance is discussed. For part III see Ref. [1]. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

Reaction of the H atom in gamma-irradiated ferrous sulphate solutions

International Nuclear Information System (INIS)

Mathews, R.W.

1977-10-01

The effect of sulphuric acid, ferrous and ferric ion, and oxygen concentrations on G(Fe 3+ ) values from cobalt-60 gamma-irradiated soltuions has been studied. Kinetic expressions were derived for reaction models involving reactions of various forms of the H atom and additional reactions postulated to be of importance at high solute concentration. Three models were assumed invoking the additional reactions: (1) an independent yield of an excited water species; (2) increasing contributions from interspur reactions of well established species at increasing solute concentration; (3) inhibition of charge pair recombination by acid and scavenger species. The calculated G(Fe 3+ ) values from the various models were compared by the least squares method with experimental G(Fe 3+ ) values from over 600 irradiations. Model 3 provided the best fit to the data for the least number of adjustable parameters. No evidence for more than one form of H atom was found with this model. (J.R.)

Acid hydrolysis of Curcuma longa residue for ethanol and lactic acid fermentation.

Science.gov (United States)

Nguyen, Cuong Mai; Nguyen, Thanh Ngoc; Choi, Gyung Ja; Choi, Yong Ho; Jang, Kyoung Soo; Park, Youn-Je; Kim, Jin-Cheol

2014-01-01

This research examines the acid hydrolysis of Curcuma longa waste, to obtain the hydrolysate containing lactic acid and ethanol fermentative sugars. A central composite design for describing regression equations of variables was used. The selected optimum condition was 4.91% sulphuric acid, 122.68°C and 50 min using the desirability function under the following conditions: the maximum reducing sugar (RS) yield is within the limited range of the 5-hydroxymethylfurfural (HMF) and furfural concentrations. Under the condition, the obtained solution contained 144 g RS/L, 0.79 g furfural/L and 2.59 g HMF/L and was directly fermented without a detoxification step. The maximum product concentration, average productivity, RS conversion and product yield were 115.36 g/L, 2.88 g/L/h, 89.43% and 64% for L-lactic acid; 113.92 g/L, 2.59 g/L/h, 88.31% and 63.29% for D-lactic acid; and 55.03 g/L, 1.38 g/L/h, 42.66 and 30.57%, respectively, for ethanol using a 7-L jar fermenter. Copyright © 2013. Published by Elsevier Ltd.

Sulphur XANES Analysis of Cultured Human Prostate Cancer Cells

International Nuclear Information System (INIS)

Kwiatek, W.M.; Podgorczyk, M.; Paluszkiewicz, Cz.; Balerna, A.; Kisiel, A.

2008-01-01

Prostate cancer is one of the most commonly diagnosed cancers in men throughout the world. It is believed that changes to the structure of protein binding sites, altering its metabolism, may play an important role in carcinogenesis. Sulphur, often present in binding sites, can influence such changes through its chemical speciation. Hence there is a need for precise investigation of coordination environment of sulphur. X-ray absorption near edge structure spectroscopy offers such possibility. Cell culture samples offer histologically well defined areas of good homogeneity, suitable for successful and reliable X-ray absorption near edge structure analysis. This paper presents sulphur speciation data collected from three different human prostate cancer cell lines (PC-3, LNCaP and DU-145). Sulphur X-ray absorption near edge structure analysis was performed on K-edge structure. The spectra of cells were compared with those of cancerous tissue and with organic substances as well as inorganic compounds. (authors)

Concentration of volatile sulphur-containing compounds along the gastrointestinal tract of pigs fed a high-sulphur or a low-sulphur diet

DEFF Research Database (Denmark)

Poulsen, Henrik Vestergaard; Canibe, Nuria; Finster, Kai

2010-01-01

Volatile sulphur-containing compounds (VSC) are formed in large quantities in the gastrointestinal tract (GI-tract) of pigs and upon excretion from the animal; these compounds are released from the faeces causing emission of foul odour. However, very little is known about the rate and extent of t...

Accidental sulphuric acid poisoning in a newborn

African Journals Online (AJOL)

2015-05-18

May 18, 2015 ... CASE REPORT. Niger J Paed 2015; 42 (3):237 –240. Abdulkadir I. Hassan L. Abdullahi F. Akeredolu FD. Purdue S. Okpe M. Sobowale AM. Adewumi OA. Abdullahi U. Onadiran ... Recommended management protocols include resting the esophagus or the ... of acid 5 hours prior to presentation. The acid ...

15N NMR spectroscopic investigation of nitrous and nitric acids in sulfuric acid solutions of varying acidities

International Nuclear Information System (INIS)

Prakash, G.K.S.; Heiliger, L.; Olah, G.A.

1990-01-01

Both nitrous and nitric acids were studied in sulfuric acid solutions of varying acid strengths by 15 N NMR spectroscopy. The study gives new insights into the nature of intermediates present at different acid strengths. Furthermore, we have also discovered a novel redox reaction between NO 2 + and NO + ions involving the intermediacy of their respective acids. A mechanism is proposed to explain the observed results. 13 refs., 2 figs., 1 tab

Amination of oxy acids in aqueous solution by gamma-irradiation

International Nuclear Information System (INIS)

Ema, Kimiko; Kato, Taizo; Shinagawa, Mutsuaki

1978-01-01

Alanin, β-alanine, glicine, and aspartic, α-amino-n-butyric, and γ-amino-n-butyric acids were obtained by γ-irradiation of aqueous ammonia solutions of lactic, β-oxypropionic, glycolic, malic, α-oxybutyric, and γ-oxybutyric acids, respectively. The yields of amino acids were examined for functions of radiation dose (0.75 - 3.55Mrad), concentrations of oxy acid (0.01 - 0.1M) and ammonia (0.1 - 15M), and substances added as radical (potassium iodide), and hydrated electron (nitrous oxide) scavengers. The maximum G-values were 0.6 for alanine in a solution of 0.1M lactic acid-4M ammonia and some nitrous oxide and 1.14 for β-alanine in a solution of 0.1M β-oxypropionic acid and 0.7M ammonia. The yield of alanine increased with increased concentrations of lactic acid and ammonia due to saturation of nitrous oxide but decreased when potassium iodide (0.03M) was added. The yield of β-alanine showed a maximum increase at ca. 0.7M ammonia and decreased when potassium iodide and nitrous oxide were added. Serine was obtained from G = 0.002 in a solution of β-oxypropionic acid and increased to G = 0.058 due to saturation of nitrous oxide. The manner of chemical amination due to radiation was studied from the above results. In general, oxy acids from which hydrogen has been abstracted by an H or OH radical react with ammonia to form amino acids. The effect of ammonia concentration on the yield of amino acids demonstrates that the NH 2 radical abstracts the α-hydrogen of lactic acid but does not react with the β-hydrogen of β-oxypropionic acid. The effect of nitrous oxide indicates that hydrated electrons interfere with alanine formation, contribute to β-alanine formation, react with the carboxyl group of lactic acids to form lactamide, and abstract the β-hydroxyl group of β-oxypropionic acids to form β-alanine. (Bell, E.)

Solubility of xenon in amino-acid solutions. II. Nine less-soluble amino acids

Science.gov (United States)

Kennan, Richard P.; Himm, Jeffrey F.; Pollack, Gerald L.

1988-05-01

Ostwald solubility (L) of xenon gas, as the radioisotope 133Xe, has been measured as a function of solute concentration, at 25.0 °C, in aqueous solutions of nine amino acids. The amino-acid concentrations investigated covered much of their solubility ranges in water, viz., asparagine monohydrate (0-0.19 M), cysteine (0-1.16 M), glutamine (0-0.22 M), histidine (0-0.26 M), isoleucine (0-0.19 M), methionine (0-0.22 M), serine (0-0.38 M), threonine (0-1.4 M), and valine (0-0.34 M). We have previously reported solubility results for aqueous solutions of six other, generally more soluble, amino acids (alanine, arginine, glycine, hydroxyproline, lysine, and proline), of sucrose and sodium chloride. In general, L decreases approximately linearly with increasing solute concentration in these solutions. If we postulate that the observed decreases in gas solubility are due to hydration, the results under some assumptions can be used to calculate hydration numbers (H), i.e., the number of H2O molecules associated with each amino-acid solute molecule. The average values of hydration number (H¯) obtained at 25.0 °C are 15.3±1.5 for asparagine, 6.8±0.3 for cysteine, 11.5±1.1 for glutamine, 7.3±0.7 for histidine, 5.9±0.4 for isoleucine, 10.6±0.8 for methionine, 11.2±1.3 for serine, 7.7± 1.0 for threonine, and 6.6±0.6 for valine. We have also measured the temperature dependence of solubility L(T) from 5-40 °C for arginine, glycine, and proline, and obtained hydration numbers H¯(T) in this range. Between 25-40 °C, arginine has an H¯ near zero. This may be evidence for an attractive interaction between xenon and arginine molecules in aqueous solution.

Concerning the acid dew point in waste gases from combustion processes

Energy Technology Data Exchange (ETDEWEB)

Knoche, K.F.; Deutz, W.; Hein, K.; Derichs, W.

1986-09-01

The paper discusses the problems associated with the measurement of acid dew point and of sulphuric acid-(say SO/sub 3/-)concentrations in the flue gas from brown coal-fired boiler plants. The sulphuric acid content in brown coal flue gas has been measured at 0.5 to 3 vpm in SO/sub 2/ concentrations of 200 to 800 vpm. Using a conditional equation, the derivation of which from new formulae for phase stability is described in the paper, an acid dew point temperature of 115 to 125/sup 0/C is produced.

Modelling copper solvent extraction from acidic sulphate solutions using MOC 45

Directory of Open Access Journals (Sweden)

Alguacil, F. J.

1998-05-01

Full Text Available A mathematical model to predict the extraction has been developed for the Cu-MOC 45 system. The model consists of sets of nonlinear mass action and mass balance equations where the dimerization of the oxime was also considered. The predictive model calculated the equilibrium concentrations from the total oxime concentration, total copper concentration, initial pH value and the O/A volume phase ratio. The model suggests that the extraction of copper can be defined by the existence of two species into the organic solution: CuR₂ (k^ext = 4.2 and Cu(HR₂₂ (k^ext = 10.000- The initial oxime concentration defines the predominancy in the organic solution of both species. The model can be used to predict copper extraction isotherm as well as copper stripping with sulphuric acid.

Se desarrolla un modelo matemático para predecir el proceso de extracción en el sistema Cu-MOC 45. El modelo consiste en un conjunto de ecuaciones en el que se considera la dimerización de la oxima. El modelo permite predecir la extracción a partir de las concentraciones totales de la oxima y del cobre, del pH inicial y de la relación de fases O/A. La extracción de cobre responde a la existencia de dos especies en la fase orgánica: CuR₂ (k^ext = 4,2 y Cu(HR₂₂ (k^ext = 10.000. La predominancia de una u otra especie en esta fase depende de la concentración inicial de la oxima. El modelo también puede predecir las isotermas de extracción y la reextracción de cobre mediante ácido sulfúrico.

Interactions of acidic solutions with sediments: a case study

International Nuclear Information System (INIS)

Peterson, S.R.; Serne, R.J.; Felmy, A.R.; Erikson, R.L.; Krupka, K.M.; Gee, G.W.

1984-01-01

A methodology is presented for investigating the chemical interactions of acidic solutions with sediments. The MINTEQ geochemical computer code was used to predict solid-phase reactions that might occur when acidic solutions contact neutral sediments which, in turn, may control the concentrations of certain dissolved components. Results of X-ray diffraction analysis of laboratory samples of sediments that have been contacted with acidic uranium mill tailings solutions suggest gypsum and jarosite precipitated. These same mineralogical changes were identified in sediment samples collected from a drained uranium mill evaporation pond (Lucky Mc mine in Wyoming) with a 10-year history of acid attack. Geochemical modeling predicted that these same phases and several amorphous solids not identifiable by X-ray diffraction should have precipitated in the contacted sediments. An equilibrium conceptual model consisting of an assemblage of minerals and amorphous solid phases was then developed to represent a sediment column through which uranium mill tailings solutions were percolated. The MINTEQ code was used to predict effluent solution concentrations resulting from the reactions of the tailings solution with the assemblage of solid phases in the conceptual model. The conceptual model successfully predicted the concentrations of several of the macro-constituents (e.g., Ca, SO 4 , Al, Fe, and Mn), but was not successful in modeling the concentrations of trace elements. The lack of success in predicting the observed trace metal concentrations suggests that other mechanisms, such as adsorption, must be included in future models. The geochemical modeling methodology coupled with the laboratory and field studies should be applicable to a variety of waste disposal problems

Radioisotopic determination methods of sulphur dispersion and sulphur blooming in rubber compounds

International Nuclear Information System (INIS)

Goraczka, W.; Koczorowska, E.

1997-01-01

It is well known that the concentration of sulphur in rubber compounds essentially effects the structure of the vulkanizate network. But there are no efficient and accurate methods to estimate the dispersion and migration (blooming) of curatives in raw rubber. In the work radioisotope methods have been analyzed to study the dispersion of curatives, physical and chemical processes in rubber and to optimize technical conditions of tire production. The radioactivity of the 35 S isotope introduced into rubber compounds has been measured by volumetric and surface methods. It was proved that the radioisotopic methods can be used in the studies. Experimental data of the effect of selected technological factors on these processes are presented. Rubber compounds containing soluble sulphur were made for such investigations. These methods permit detection of concentrations 10 -6 g of the radioactive isotope per 0.1 g of rubber compound. The sensitivity of these methods enables the investigation of radioisotope behaviour in rubber compounds during processing on an industrial scale without any hazards for workers

Characterization of selectively etched halloysite nanotubes by acid treatment

Science.gov (United States)

Garcia-Garcia, Daniel; Ferri, Jose M.; Ripoll, Laura; Hidalgo, Montserrat; Lopez-Martinez, Juan; Balart, Rafael

2017-11-01

Halloysite nanotubes (HNTs) are a type of naturally occurring inorganic nanotubes that are characterized by a different composition between their external and internal walls. The internal walls are mainly composed of alumina whilst external walls are composed of silica. This particular structure offers a dual surface chemistry that allows different selective surface treatments which can be focused on increasing the lumen, increasing porosity, etc. In this work, HNTs were chemically treated with different acids (sulphuric, acetic and acrylic acid), for 72 h at a constant temperature of 50 °C. As per the obtained results, the treatment with sulphuric acid is highly aggressive and the particular shape of HNTs is almost lost, with a remarkable increase in porosity. The BET surface area increases from 52.9 (untreated HNTs) up to 132.4 m2 g-1 with sulphuric acid treatment, thus showing an interesting potential in the field of catalysis. On the other hand, the treatment with acetic acid led to milder effects with a noticeable increase in the lumen diameter that changed from 13.8 nm (untreated HNTs) up to 18.4 nm which the subsequent increase in the loading capacity by 77.8%. The aluminium content was measured by X-ray fluorescence (XRF) and laser induced breakdown spectroscopy (LIBS). The final results using two systems, suggest a good correlation between the acid strength and the aluminium reduction. Consequently, is possible to conclude that new applications for HNTs can be derived from selective etching with acids. Sulphuric acid widens the potential of HNTs in the field of catalysis while weak acids such as acetic and acrylic acids give a controlled and homogeneous lumen increase with the corresponding increase in the loading capacity.

Comparison of the effect of gamma irradiation, heat-radiation combination, and sulphur dioxide generating pads on decay and quality of grapes

International Nuclear Information System (INIS)

Thomas, Paul; Brij Bhushan; Joshi, M.R.

1995-01-01

Effect of gamma irradiation, heat-radiation combination and in-package sulphur dioxide fumigation on fungal decay, and quality of seedless grape cultivars, Thompson, Sonaka and Tas-A-Ganesh was evaluated under different storage regimes. Irradiation at 2 kGy or a combination of hot water dip (50 degC, 5 min), plus irradiation (1 kGy) showed less spoilage due to Rhizopus spp. and Botrytis spp. in grapes packaged in tissue paper lined boxes and stored at 4 deg, 15 deg and 25 degC. Storage in polyethylene lined boxes increased the fungal rot. In-package sulphur dioxide generating pad was most effective for control of decay in polyethylene lined boxes stored at 10 deg and 20 degC, but caused berry bleaching. Irradiation at 2.5 or 3.5 kGy controlled decay at 10 degC, but not so effectively at 20 degC. Organoleptic quality, berry firmness, and soluble solids were not affected by irradiation, but decreases in titratable acids and ascorbic acid were recorded. Packaging in polyethylene lined boxes retained berry turgidity, while slight shrivelling occurred in tissue paper lined boxes. The results indicate that gamma irradiation has potential as an alternative to sulphur dioxide fumigation for decay control during shipping and storage. (author). 20 refs., 4 tabs

Process for the removal of radium from acidic solutions containing same

International Nuclear Information System (INIS)

Scheitlin, F.M.

1984-01-01

Radium is removed from an inorganic-acid solution contacting the solution with coal fly ash to effect adsorption of the radium on the ash. The radium-containing ash then is separated from the solution. The process is simple and efficient. High radium-distribution coefficients are obtained even at room temperature. Coal fly ash is an inexpensive, acid-resistant, high-surface-area material which is available in large quantities. The invention is applicable, for example, to the recovery of 226 Ra from nitric acid solutions which have been used to leach radium from uranium-mill tailings, and thus contain thorium and uranium. The contaminated fly ash may be incorporated in a suitable matrix and stored, and the residual solutions processed to separate uranium and thorium. (author)

Acid-base equilibrium in aqueous solutions of 1,3-dimethylbarbituric acid as studied by 13C NMR spectroscopy

Science.gov (United States)

Gryff-Keller, A.; Kraska-Dziadecka, A.

2011-12-01

13C NMR spectra of 1,3-dimethylbarbituric acid in aqueous solutions of various acidities and for various solute concentrations have been recorded and interpreted. The spectra recorded at pH = 2 and below contain the signals of the neutral solute molecule exclusively, while the ones recorded at pH = 7 and above only the signals of the appropriate anion, which has been confirmed by theoretical GIAO-DFT calculations. The signals in the spectra recorded for solutions of pH pH variation have been observed for the parent barbituric acid.

Three-decade changes in chemical composition of precipitation in Guangzhou city, southern China: has precipitation recovered from acidification following sulphur dioxide emission control?

Directory of Open Access Journals (Sweden)

Yunting Fang

2013-09-01

Full Text Available We examined if precipitation had recovered from acidification in Guangzhou, the third biggest city in China, and if sulphur deposition in precipitation had decreased, and to what extent if yes, following abatement strategies in sulphur dioxide (SO2 emission and energy use implemented since 2001. SO2 emissions were decreasing steadily since 2001, but a marked recovery of precipitation acidity occurred only since 2005; precipitation pH values decreased from 4.65 in 2001 to 4.34 in 2005 and then increased to 5.08 in 2010, while in the same period acid rain (pH<5.6 frequency increased from 70% to 81% and then decreased to 48%. During this period, the change in pH value and sulphate concentration more reflected the patterns of SO2 emission at provincial and national scales than at the local scale, suggesting that precipitation chemical composition was largely controlled by the emissions of pollutants from surrounding areas of the study city. Since 2001, sulphate deposition in precipitation decreased significantly (by 40% but nitrogen deposition remained unaltered. More importantly, the current sulphur (43 kg S ha−1 yr−1 as sulphate and nitrogen depositions (35 kg N ha−1 yr−1 as ammonium plus nitrate in 2010 were still among the highest in China. These results highlight the fact that ambient sulphur and nitrogen deposition still pose a threat to the health of both terrestrial and aquatic ecosystems. Precipitation may become more acidified in the future because the deposition of alkaline dusts containing calcium is also likely to decrease with stricter SO2 emission control policy and reduced construction activities. Additionally, we recommend that a reduction of emissions of nitrogen and chlorine bearing pollutants is urgently required for complete control on acid deposition.

Polioencephalomalacia in ruminants caused by excessive amount of sulphur - a review

Directory of Open Access Journals (Sweden)

Lutnicki Krzysztof

2014-06-01

Full Text Available Polioencephalomalacia as a result of sulphur excess is a growing problem in cattle and sheep, mainly in young, growing animals. It is common in different regions of the world. The disease develops favoured by certain conditions such as sustained provision of feed and water with high sulphur content, use of dietary supplements containing sulphur, and a habitat with high hydrogen sulphide concentration. Pathogenesis of the disease is complex, but very important are oxidative-antioxidative imbalance, dysfunction of vessels, and secondary cerebral cortex ischaemia as a result of direct and/or indirect action of sulphur metabolites, namely hydrogen sulphide, sulphides, and sulphites. Clinical signs and changes in the cerebral cortex in the form of degenerative necrotic lesions are similar to those observed in polioencephalomalacia caused by vitamin B1 deficiency, and lead and salt intoxication. Highly increased sulphur content (more than 0.3-0.4 of dry matter in the diet is the basis for differential diagnosis, as well the high concentration of hydrogen sulphide in gas and sulphides in rumen fluid. In prophylaxis and treatment the most important measure is to limit sulphur intake and in acute cases to neutralise low pH in rumen and administer vitamin B1 injections.

Efficacy and phytotoicity of lime sulphur in organic apple production

NARCIS (Netherlands)

Holb, I.J.; Jong, de P.F.; Heijne, B.

2003-01-01

Curative and preventive efficacy and phytotoxicity of lime sulphur spray schedules, based on a warning system, were evaluated in the Netherlands during two growing seasons under field conditions. In most cases, lime sulphur treatments applied either curatively or preventively resulted in

Uranium and thorium leached from uranium mill tailing of Guangdong province (CN)) and its implication for radiological risk

International Nuclear Information System (INIS)

Wang, J.; Liu, J.; Zhu, L.; Qi, J. Y.; Chen, Y. H.; Xiao, T. F.; Fu, S. M.; Wang, C. L.; Li, J. W.

2012-01-01

The paper focused on the leaching behaviour of uranium (U) and thorium (Th) from uranium mill tailing collected from the Uranium Mill Plant in Northern Guangdong Province (CN)). Distilled water (pH 6) and sulphuric acid solution (pH 4 and 3) were used as solvent for the leaching over 22 weeks. It was found that the cumulative leach fraction from the mill tailing was 0.1, 0.1 and 0.7 % for U release, and overall 0.01 % for Th release, using distilled water, sulphuric acid solution of pH 4 and pH 3 as leaching agents, respectively. The results indicate that (1) the release of U and Th in uranium mill tailing is a slow and long-term process; (2) surface dissolution is the main mechanism for the release of U and Th when sulphuric acid solution of pH 3 is employed as the leaching agent; (3) both U and Th are released by diffusion when using sulphuric acid solution of pH 4 as the leaching agent and (4) U is released by surface dissolution, while Th is released by diffusion when using distilled water as the leaching agent. The implication for radiological risk in the real environment was also discussed. (authors)

Inhibitive action of some plant extracts on the corrosion of steel in acidic media

Energy Technology Data Exchange (ETDEWEB)

Abdel-Gaber, A.M. [Department of Chemistry, Faculty of Science, Alexandria University, Ibrahimia, P.O. Box 426, Alexandria 21321 (Egypt)]. E-mail: ashrafmoustafa@yahoo.com; Abd-El-Nabey, B.A. [Department of Chemistry, Faculty of Science, Alexandria University, Ibrahimia, P.O. Box 426, Alexandria 21321 (Egypt); Sidahmed, I.M. [Department of Chemistry, Faculty of Science, Alexandria University, Ibrahimia, P.O. Box 426, Alexandria 21321 (Egypt); El-Zayady, A.M. [Department of Chemistry, Faculty of Science, Alexandria University, Ibrahimia, P.O. Box 426, Alexandria 21321 (Egypt); Saadawy, M. [Department of Chemistry, Faculty of Science, Alexandria University, Ibrahimia, P.O. Box 426, Alexandria 21321 (Egypt)

2006-09-15

The effect of extracts of Chamomile (Chamaemelum mixtum L.), Halfabar (Cymbopogon proximus), Black cumin (Nigella sativa L.), and Kidney bean (Phaseolus vulgaris L.) plants on the corrosion of steel in aqueous 1 M sulphuric acid were investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. EIS measurements showed that the dissolution process of steel occurs under activation control. Potentiodynamic polarization curves indicated that the plant extracts behave as mixed-type inhibitors. The corrosion rates of steel and the inhibition efficiencies of the extracts were calculated. The results obtained show that the extract solution of the plant could serve as an effective inhibitor for the corrosion of steel in sulphuric acid media. Inhibition was found to increase with increasing concentration of the plant extract up to a critical concentration. The inhibitive actions of plant extracts are discussed on the basis of adsorption of stable complex at the steel surface. Theoretical fitting of different isotherms, Langmuir, Flory-Huggins, and the kinetic-thermodynamic model, were tested to clarify the nature of adsorption.

The implications of the new sulphur limits on the European Ro-Ro sector

DEFF Research Database (Denmark)

Zis, Thalis; Psaraftis, Harilaos N.

-based alternatives. The exact repercussions of the new sulphur limits are difficult to identify in the wake of significant recent reductions of the fuel prices for both low-sulphur and heavy fuel oil. This paper presents a modal split model that estimates modal shifts vis-a-vis competing maritime and land......In an effort to reduce the environmental impacts of maritime transportation, the International Maritime Organization (IMO) designated special Sulphur Emission ControlAreas (SECAs) where ships are required to use low-sulphur fuel. In January 2015, the sulphur limit within SECAs was lowered to 0.......1%, which can only be achieved if vessels are using pricier ultra-low sulphur fuel, or invest in abatement technologies. The increased operating costs borne by Ro-Ro operators in SECAs due to the stricter limits can result in the shutting down of some routes and a redistribution of cargo flows with land...

Sulphur-oxidising and Sulphate-reducing Communities in Brazilian Mangrove Sediments

NARCIS (Netherlands)

Varon-Lopez, Maryeimy; Dias, A.C.F; Fasanella, C.C.; Durrer, A.; Melo, I.S.; Kuramae, E.E.; Andreote, F.D.

2014-01-01

Mangrove soils are anaerobic environments rich in sulphate and organic matter. Although the sulphur cycle is one of the major actors in this ecosystem, little is known regarding the sulphur bacteria communities in mangrove soils. We investigated the abundance, composition and diversity of

One-electron reduction reactions with enzymes in solution

International Nuclear Information System (INIS)

Bisby, R.H.; Cundall, R.B.; Redpath, J.L.; Adams, G.E.

1976-01-01

At pH 8 and above, hydrated electrons react with ribonuclease lysozyme and α-chymotrypsin to form transient products whose spectra resemble, but are not identical to, those for the RSSR - radical anion already known for simple disulphides. Assuming a value for the extinction coefficient similar to that for RSSR - in simple disulphides, only a fraction of the hydrated electrons are shown to react with the disulphide bridges: the remainder react at other sites in the protein molecule, such as histidine, tyrosine and, in lysozyme, tryptophan residues, giving rise to comparatively weak optical absorptions between 300 and 400 nm. This has been substantiated by studying the reaction of e - sub(aq) with subtilisin Novo (an enzyme which does not contain disulphide bridges), with enzymes in which the sulphur bridges have been oxidised and with some amino acid derivatives. On lowering the pH of the solution the intensity of the RSSR - absorption diminishes as the protonated histidine residues become the favoured reaction sites. In acid solutions (pH 2 to 3) the transient optical absoptions observed are due to reactions of hydrogen atoms with the aromatic amino acids tyrosine, tryptophan and phenylalanine. The CO - 2 radical anion is only observed to transfer an electron to disulphide groups in ribonuclease, although the effect of repeated pulsing shows that some reaction must occur elsewhere in the protein molecule. In acid solutions, protonation of the electron adduct appears to produce the RSSRH. radical, whose spectrum has a maximum at 340 nm. (author)

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African Journals Online (AJOL)

metallic guld, gold oxide and gold(III) solutions in hydrochloric and sulphuric acids. Moreover ... incorporation of a solid sample of the element in a carbon paste electrode. ... closed cell containing hydrochloric or sulphuric acid as electrolyte. .... Near 265 mV is observed a quasi-reversible electrochemical system linked to the.

Determination of nonmetallic elements in actinide complexes by oxygen flask combustion (OFC) (Part 2). Sulphur

International Nuclear Information System (INIS)

Ruikar, P.B.; Nagar, M.S.; Subramanian, M.S.

1989-01-01

This report describes the determination of sulphur in metallic complexes by oxygen flask combustion followed by conductivity titration with standard barium acetate solution in alcoholic medium and lead electrode titration using a lead ion sensitive electrode. Various organic ligands and uranyl and plutonyl synergistic complexes have been analysed by both these methods and the precision and accuracy of the results have been found to be satisfactory. (author). 12 refs., 12 tabs

Analytical protocols for the determination of sulphur compounds characteristic of the metabolism of Chlorobium limicola

Directory of Open Access Journals (Sweden)

A. Aliboni

2015-09-01

Full Text Available Chlorobium limicola belongs to the green sulphur bacteria that has a potential for technological applications such as biogas clean up oxidising hydrogen sulphide to elemental sulphur through photosynthetic process. In the present work, analytical methods are described for the determination of different sulphur species in C. limicola cultures – sulphide by GC-FPD, sulphate by ionic HPLC and elemental sulphur by RP HPLC. The latter method eliminates the need for chloroform extraction of water suspensions of elemental sulphur. Data from sulphide and elemental sulphur analyses have been compared with ones coming from more traditional analytical methodologies.

Experiences in sulphur capture in a 30 MWth Circulating Fluidized Bed boiler under oxy-combustion conditions

International Nuclear Information System (INIS)

Gómez, M.; Fernández, A.; Llavona, I.; Kuivalainen, R.

2014-01-01

CO 2 and SO 2 from fossil fuel combustion are contributors to greenhouse effect and acid rain respectively. Oxy-combustion technology produces a highly concentrated CO 2 stream almost ready for capture. Circulating Fluidized Bed (CFB) boiler technology allows in-situ injection of calcium-based sorbents for efficient SO 2 capture. CIUDEN's 30 MWth CFB boiler, supplied by Foster Wheeler and located at the Technology Development Centre for CO 2 Capture and Transport (es.CO 2 ) in Spain, is the first of its kind for executing test runs at large pilot scale under both air-combustion and oxy-combustion conditions. In this work, SO 2 emissions under different scenarios have been evaluated. Variables such as limestone composition, Ca/S molar ratio and bed temperature among others have been considered along different test runs in both air-combustion and oxy-combustion conditions to analyse its influence on SO 2 abatement. Fly and bottom ash, together with flue gas analysis have been carried-out. Desulphurization performance tests results are presented. - Highlights: •Sulphur capture efficiency (%) was higher in oxy-combustion compared to air-combustion in a 30 MW thermal CFB boiler using anthracite and limestone as sulphur sorbent. •For a Ca/S molar ratio higher than 2.6 there was barely any improvement on sulphur capture efficiency for both air-combustion and oxy-combustion conditions in a 30 MW thermal CFB boiler using anthracite and limestone as sulphur sorbent. •Optimum temperature for sulphur capture at a fixed Ca/S molar ratio is around 880–890 °C under oxy-combustion conditions and for anthracite coal with limestone as sorbent in a 30 MW thermal CFB boiler

Sulphur and lead isotopes in strata-bound deposits, ch. 8

International Nuclear Information System (INIS)

Sangster, D.F.

1976-01-01

The use of sulphur and lead isotopes as isotopic tracers in the study of ore deposits containing these elements is reviewed. A discussion of the general theory, including abundance and fractionation of sulphur isotopes, single-stage leads, and anomalous leads (two-stage) is given. Attention is paid to sulphur isotopes enclosed in deposits which are located in marine host rocks and in rocks of continental or near-continental origin, as well as in deposits of the conglomerate-U(-Au) type. The lead isotope content of volcanogenic massive sulphide deposits and carbonate-hosted lead-zinc deposits is discussed

Fluoresence quenching of riboflavin in aqueous solution by methionin and cystein

International Nuclear Information System (INIS)

Droessler, P.; Holzer, W.; Penzkofer, A.; Hegemann, P.

2003-01-01

The fluorescence quantum distributions, fluorescence quantum yields, and fluorescence lifetimes of riboflavin in methanol, DMSO, water, and aqueous solutions of the sulphur atom containing amino acids methionin and cystein have been determined. In methanol, DMSO, and water (pH=4-8) only dynamic fluorescence reduction due to intersystem crossing and internal conversion is observed. In aqueous methionin solutions of pH=5.25-9 a pH independent static and dynamic fluorescence quenching occurs probably due to riboflavin anion-methionin cation pair formation. In aqueous cystein solutions (pH range from 4.15 to 9) the fluorescence quenching increases with rising pH due to cystein thiolate formation. The cystein thiol form present at low pH does not react with neutral riboflavin. Cystein thiolate present at high pH seems to react with neutral riboflavin causing riboflavin deprotonation (anion formation) by cystein thiolate reduction to the cystein thiol form

European transboundary acidifying air pollution. Ten years calculated fields and budgets to the end of the first Sulphur Protocol

Energy Technology Data Exchange (ETDEWEB)

Barrett, K.; Seland, Oe.; Foss, A.; Mylona, S.; Sandnes, H.; Styve, H.; Tarrason, L.

1995-07-01

The Cooperative Programme for the Monitoring and Evaluation of the Long Range Transmission and Air Pollutants in Europe, EMEP, plays an integral part in data collection and scientific cooperation for implementation of the 1979 Geneva Convention on Long Range Transboundary Air Pollution. Within EMEP, the Meteorological Synthesizing Centre - West (MSC-W) is an international technical centre. The purpose of the MSC-W, focusing in part on acidifying substances, is to estimate the concentrations of relevant sulphur and nitrogen pollutants across Europe on the basis of emission information and meteorological data, and to estimate the transboundary fluxes of these substances. Responding to these specific obligations, the report presents calculations of sulphur and nitrogen concentrations and depositions and of their transboundary fluxes. The calculations are performed by the receptor oriented one layer trajectory (Lagrangian) acid deposition model, which during 1995 has been used to estimate acidifying pollutant fluxes for the ten year period 1985-1994. This corresponds to the period between initial signing and conclusion of the first Sulphur Protocol, signed in Helsinki in 1985. 90 refs., 42 figs., 43 tabs.

Co-precipitation of plutonium(IV) and americium(III) from nitric acid-oxalic acid solutions with bismuth oxalate

International Nuclear Information System (INIS)

Pius, I.C.; Noronha, D.M.; Chaudhury, Satyajeet

2017-01-01

Co-precipitation of plutonium and americium from nitric acid-oxalic acid solutions with bismuth oxalate has been investigated for the removal of these long lived α-active nuclides from waste solutions. Effect of concentration of bismuth and oxalic acid on the co-precipitation of Pu(IV) from 3 M HNO_3 has been investigated. Similar experiments were also carried out from 3.75 M HNO_3 on co-precipitation of Am(III) to optimize the conditions of precipitation. Strong co-precipitation of Pu(IV) and Am(III) with bismuth oxalate indicate feasibility of treatment of plutonium and americium bearing waste solutions. (author)

Measurement of sulphur-35 in the coolant gas of the Windscale Advanced Gas-Cooled Reactor

International Nuclear Information System (INIS)

Sandalls, F.J.

1978-03-01

Sulphur is an important element in some food chains and the release of radioactive sulphur to the environment must be closely controlled if the chemical form is such that it is available or potentially available for entering food chains. The presence of sulphur-35 in the coolant gas of the Windscale Advanced Gas-Cooled Reactor warranted a study to assess the quantity and chemical form of the radioactive sulphur in order to estimate the magnitude of the potential environmental hazard which might arise from the release of coolant gas from Civil Advanced Gas-Cooled Reactors. A combination of gas chromatographic and radiochemical analyses revealed carbonyl sulphide to be the only sulphur-35 compound present in the coolant gas of the Windscale Reactor. The concentration of carbonyl sulphide was found to lie in the range 40 to 100 x 10 -9 parts by volume and the sulphur-35 specific activity was about 20 mCi per gramme. The analytical techniques are described in detail. The sulphur-35 appears to be derived from the sulphur and chlorine impurities in the graphite. A method for the preparation of carbonyl sulphide labelled with sulphur-35 is described. (author)

Adsorption of pertechnetate ion on various active carbons from mineral acid solutions

International Nuclear Information System (INIS)

Ito, K.

1991-01-01

The adsorption behavior of pertechnetate ion (TcO 4 - ) on active carbon has been studied for various acid solutions, taking as indicative value the distribution coefficient K d of Tc between active carbon surface and solution. In a system where the total anion concentration of the acid and its sodium salt was maintained constant, modifying the pH of the solution proved distinctly to influence the Tc adsorption behavior of active carbon: taking the case of active carbon derived from coconut shell, increasing the acidity raised K d ; around neutrality there occurred a level stage; in the alkali region, K d declined. The rise of K d in the acid region, however, was observed only with active carbon derived from coconut shell, from oil pitch or from saw dust; it failed to occur when the active carbon was derived from coal or from bone. With a hydrochloric acid system, the rise of K d started around 1 M (mol dm -1 ) HCl. Beyond 3 M, on the other hand, a breakthrough occurred, and K d declined with increasing acidity. With a nitric acid system, K d rose from 1 M, and the breakthrough occurred at 2 M. When the adsorption was left to equilibrate beyond 4 h, desorption displacement of TcO 4 - by a coexisting other anion was observed in the case of perchloric acid solutions of concentration above 0.1 M and with sulfuric acid solutions above 0.5 M. (author)

Mesoporous titanium-manganese dioxide for sulphur mustard and soman decontamination

International Nuclear Information System (INIS)

Stengl, Vaclav; Bludska, Jana; Oplustil, Frantisek; Nemec, Tomas

2011-01-01

Highlights: → New nano-dispersive materials for warfare agents decontamination. → 95% decontamination activities for sulphur mustard. → New materials base on titanium and manganese oxides. -- Abstract: Titanium(IV)-manganese(IV) nano-dispersed oxides were prepared by a homogeneous hydrolysis of potassium permanganate and titanium(IV) oxo-sulphate with 2-chloroacetamide. Synthesised samples were characterised using Brunauer-Emmett-Teller (BET) surface area and Barrett-Joiner-Halenda porosity (BJH), X-ray diffraction (XRD), infrared spectroscopy (IR), and scanning electron microscopy (SEM). These oxides were taken for an experimental evaluation of their reactivity with sulphur mustard (HD or bis(2-chloroethyl)sulphide) and soman (GD or (3,3'-dimethylbutan-2-yl)-methylphosphonofluoridate). Mn 4+ content affects the decontamination activity; with increasing Mn 4+ content the activity increases for sulphur mustard and decreases for soman. The best decontamination activities for sulphur mustard and soman were observed for samples TiMn 3 7 with 18.6 wt.% Mn and TiMn 5 with 2.1 wt.% Mn, respectively.

Investigations of the sorption of cesium from acid solutions by various inorganic sorbents

International Nuclear Information System (INIS)

Suess, M.; Pfrepper, G.

1981-01-01

Studies have been made to investigate the suitability of various inorganic sorbents for separating and obtaining cesium from acid solutions. In greater details, the distribution coefficients of cesium from nitric acid and ammonium nitrate solution were determined. To determine the saturation capacities it was necessary to plot the isotherms of adsorption from 0.5 N and 3.1 N nitric acid. Experimental sorption from a model solution, of which the composition was equal to that of the liquid Purex waste, enabled the suitability of the various exchangers for obtaining cesium from fission product solutions to be determined. From the results obtained it is apparent that ammonium phosphomolybdate is best suited for obtaining cesium from acid fission product solutions. (orig.)

Radiolysis of concentrated nitric acid solutions

International Nuclear Information System (INIS)

Nagaishi, R.; Jiang, P.Y.; Katsumura, Y.; Domae, M.; Ishigure, K.

1995-01-01

A study on electron pulse- and 60 Co γ-radiolysis of concentrated nitric acid and nitrate solutions has been carried out to elucidate the radiation induced reactions taking place in the solutions. Dissociation into NO 2 - and O( 3 P) was proposed as a direct action of the radiation on nitrate and gave the G-values were dependent on the chemical forms of nitrate: g s2 (-NO 3 - )=1.6 and g s2 (-HNO 3 )=2.2 (molecules/100eV). Based on the experimental yields of HNO 2 and reduced Ce IV , the primary yields of radiolysis products of water, g w , were evaluated to clarify the effects of nitrate on spur reactions of water in various nitrate solutions. (author)

Acid in perchloroethylene scrubber solutions used in HTGR fuel preparation processes. Analytical chemistry studies

International Nuclear Information System (INIS)

Lee, D.A.

1979-02-01

Acids and corrosion products in used perchloroethylene scrubber solutions collected from HTGR fuel preparation processes have been analyzed by several analytical methods to determine the source and possible remedy of the corrosion caused by these solutions. Hydrochloric acid was found to be concentrated on the carbon particles suspended in perchloroethylene. Filtration of carbon from the scrubber solutions removed the acid corrosion source in the process equipment. Corrosion products chemisorbed on the carbon particles were identified. Filtered perchloroethylene from used scrubber solutions contained practically no acid. It is recommended that carbon particles be separated from the scrubber solutions immediately after the scrubbing process to remove the source of acid and that an inhibitor be used to prevent the hydrolysis of perchloroethylene and the formation of acids

Radiolytic degradation of gallic acid and its derivatives in aqueous solution

International Nuclear Information System (INIS)

Melo, R.; Leal, J.P.; Takacs, E.; Wojnarovits, L.

2009-01-01

Polyphenols, like gallic acid (GA) released in the environment in larger amount, by inducing some unwanted oxidations, may constitute environmental hazard: their concentration in wastewater should be controlled. Radiolytic degradation of GA was investigated by pulse radiolysis and final product techniques in dilute aqueous solution. Subsidiary measurements were made with 3,4,5-trimethoxybenzoic acid (TMBA) and 3,4,5-trihydroxy methylbenzoate (MGA). The hydroxyl radical and hydrogen atom intermediates of water radiolysis react with the solute molecules yielding cyclohexadienyl radicals. The radicals formed in GA and MGA solutions in acid/base catalyzed water elimination decay to phenoxyl radicals. This reaction is not observed in TMBA solution. The hydrated electron intermediate of water decomposition adds to the carbonyl oxygen, the anion thus formed protonates on the ring forming cyclohexadienyl radical or on the carbonyl group forming carbonyl centred radical. The GA intermediates formed during reaction with primary water radicals in presence of oxygen transform to non-aromatic molecules, e.g., to aliphatic carboxylic acids.

Radiolytic degradation of gallic acid and its derivatives in aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Melo, R. [Instituto Tecnologico e Nuclear, UCQR, Estrada Nacional No. 10, Apartado 21, 2686-953, Sacavem (Portugal); Leal, J.P. [Instituto Tecnologico e Nuclear, UCQR, Estrada Nacional No. 10, Apartado 21, 2686-953, Sacavem (Portugal); Centro Quimica e Bioquimica, Faculdade de Ciencias da Universidade de Lisboa, 1749-016 Lisboa (Portugal); Takacs, E., E-mail: takacs@iki.kfki.hu [Institute of Isotopes, Hungarian Academy of Sciences, P.O. Box 77, H-1525 Budapest (Hungary); Wojnarovits, L. [Institute of Isotopes, Hungarian Academy of Sciences, P.O. Box 77, H-1525 Budapest (Hungary)

2009-12-30

Polyphenols, like gallic acid (GA) released in the environment in larger amount, by inducing some unwanted oxidations, may constitute environmental hazard: their concentration in wastewater should be controlled. Radiolytic degradation of GA was investigated by pulse radiolysis and final product techniques in dilute aqueous solution. Subsidiary measurements were made with 3,4,5-trimethoxybenzoic acid (TMBA) and 3,4,5-trihydroxy methylbenzoate (MGA). The hydroxyl radical and hydrogen atom intermediates of water radiolysis react with the solute molecules yielding cyclohexadienyl radicals. The radicals formed in GA and MGA solutions in acid/base catalyzed water elimination decay to phenoxyl radicals. This reaction is not observed in TMBA solution. The hydrated electron intermediate of water decomposition adds to the carbonyl oxygen, the anion thus formed protonates on the ring forming cyclohexadienyl radical or on the carbonyl group forming carbonyl centred radical. The GA intermediates formed during reaction with primary water radicals in presence of oxygen transform to non-aromatic molecules, e.g., to aliphatic carboxylic acids.

Report on the progress of work in Portugal [Processing of Low-Grade Uranium Ores]; Rapport sur l'etat d'avancement des travaux au Portugal

Energy Technology Data Exchange (ETDEWEB)

Carreira Pich, H [Junta de Energia Nuclear, Laboratorio de Fisica e Engenharia Nucleares, Sacavem (Portugal)

1967-06-15

The purpose of the principal studies until now in Portugal were the development of two types of treatment of the uranium minerals: - Traditional leaching by agitation of the ore milled in a finely sulphuric acid solution; - Leaching of the type 'heap leaching' in which the ore is hard crushed, and then sprinkles is crammed with sulphuric acid solution. Leaching tests were performed traditionally with samples of available Portuguese minerals. In most cases, the dissolution of uranium is easy and low consumption of acid. Efforts were oriented in the direction of a leaching type 'heap leaching'.

Effect of acetic acid on wet patterning of copper/molybdenum thin films in phosphoric acid solution

International Nuclear Information System (INIS)

Seo, Bo.-Hyun; Lee, Sang-Hyuk; Park, In-Sun; Seo, Jong Hyun; Choe, HeeHwan; Jeon, Jae-Hong; Hong, Munpyo; Lee, Yong Uk; Winkler, Joerg

2011-01-01

Copper metallization is a key issue for high performance thin film transistor (TFT) technology. A phosphoric acid based copper etchant is a potentially attractive alternative to the conventional hydrogen peroxide based etchant due to its longer-life expectancy time and higher stability in use. In this paper, it is shown that amount of the acetic acid in the phosphoric based copper etchant plays an important role in controlling the galvanic reaction between the copper and the molybdenum. As the concentration of acetic acid in the phosphoric mixture solution increased from 0 M to 0.4 M, the measured galvanic current density dropped from 32 mA/cm 2 to 26 mA/cm 2 , indicating that the acetic acid induces the lower galvanic reaction between the copper and the molybdenum in the solution. From the XPS analysis, with the addition of the acetic acid, the thickness of the protective MoO 2 passive film covering the molybdenum surface grew and the dissolution rate of the molybdenum thin film decreased. However, the dissolution rate of the copper thin film increased as the concentration of acetic acid in the mixture solution increased.

Effect of acetic acid on wet patterning of copper/molybdenum thin films in phosphoric acid solution

Energy Technology Data Exchange (ETDEWEB)

Seo, Bo.-Hyun; Lee, Sang-Hyuk; Park, In-Sun [Department of Materials Engineering, Korea Aerospace University, Hwajeon, Goyang, Gyonggi-do 412-791 (Korea, Republic of); Seo, Jong Hyun, E-mail: jhseo@kau.ac.kr [Department of Materials Engineering, Korea Aerospace University, Hwajeon, Goyang, Gyonggi-do 412-791 (Korea, Republic of); Choe, HeeHwan; Jeon, Jae-Hong [School of Electronics, Telecommunications and Computer Engineering, Korea Aerospace University, Hwajeon, Goyang, Gyonggi-do 412-791 (Korea, Republic of); Hong, Munpyo [Display and Semiconductor Physics, Korea University (Korea, Republic of); Lee, Yong Uk [PETEC (The Printable Electronics Technology Centre) (United Kingdom); Winkler, Joerg [PLANSEE Metal GmbH, Metallwerk-Plansee-Str. 71A-6600, Reutte (Austria)

2011-08-01

Copper metallization is a key issue for high performance thin film transistor (TFT) technology. A phosphoric acid based copper etchant is a potentially attractive alternative to the conventional hydrogen peroxide based etchant due to its longer-life expectancy time and higher stability in use. In this paper, it is shown that amount of the acetic acid in the phosphoric based copper etchant plays an important role in controlling the galvanic reaction between the copper and the molybdenum. As the concentration of acetic acid in the phosphoric mixture solution increased from 0 M to 0.4 M, the measured galvanic current density dropped from 32 mA/cm{sup 2} to 26 mA/cm{sup 2}, indicating that the acetic acid induces the lower galvanic reaction between the copper and the molybdenum in the solution. From the XPS analysis, with the addition of the acetic acid, the thickness of the protective MoO{sub 2} passive film covering the molybdenum surface grew and the dissolution rate of the molybdenum thin film decreased. However, the dissolution rate of the copper thin film increased as the concentration of acetic acid in the mixture solution increased.

Interrogating trees for isotopic archives of atmospheric sulphur deposition and comparison to speleothem records

International Nuclear Information System (INIS)

Wynn, P.M.; Loader, N.J.; Fairchild, I.J.

2014-01-01

Palaeorecords which depict changes in sulphur dynamics form an invaluable resource for recording atmospheric pollution. Tree rings constitute an archive that are ubiquitously available and can be absolutely dated, providing the potential to explore local- to regional-scale trends in sulphur availability. Rapid isotopic analysis by a novel “on-line” method using elemental analyser isotope ratio mass spectrometry (EA-IRMS) is developed, achieving sample precision of <0.4‰ using sample sizes of 40 mg wood powder. Tree cores from NE Italy show trends in pollution, evidenced through increasing concentrations of sulphur towards the youngest growth, and inverse trends in sulphur isotopes differentiating modern growth with light sulphur isotopes (+0.7‰) from pre-industrial growth (+7.5‰) influenced by bedrock composition. Comparison with speleothem records from the same location demonstrate replication, albeit offset in isotopic value due to groundwater storage. Using EA-IRMS, tree ring archives form a valuable resource for understanding local- to regional-scale sulphur pollution dynamics. - Highlights: • Sulphur isotopes from tree rings are analysed using ‘on-line’ EA combustion. • Isotopes differentiate modern growth influenced by pollution from pre-industrial growth. • Biogeochemical cycling imparts minimal delay in sulphur incorporation into tree rings. • Trends in pollution are replicated between speleothems and trees from the same location. - Sulphur isotopes extracted from tree ring records are used to identify twentieth century pollution dynamics at the local- to regional-scale

Effect of Thiobacillus thioparus 1904 and sulphur addition on odour emission during aerobic composting.

Science.gov (United States)

Gu, Wenjie; Sun, Wen; Lu, Yusheng; Li, Xia; Xu, Peizhi; Xie, Kaizhi; Sun, Lili; Wu, Hangtao

2018-02-01

The effects of sulphur and Thiobacillus thioparus 1904 on odour emissions during composting were studied. Results indicated that the sulphur addition reduced the pH and decreased cumulative emission of ammonia and the nitrogen loss by 47.80% and 44.23%, respectively, but the amount of volatile sulphur compounds (VSCs) and the sulphur loss increased. The addition of T. thioparus 1904 effectively reduced the cumulative emissions of H 2 S, methyl sulphide, methanethiol, dimethyl disulphide and the sulphur loss by 33.24%, 81.24%, 32.70%, 54.22% and 54.24%, respectively. T. thioparus 1904 also limited the nitrogen loss. The combined application of sulphur and T. thioparus 1904 resulted in the greatest amount of nitrogen retention. The accumulation of ammonia emissions was reduced by 63.33%, and the nitrogen loss was reduced by 71.93%. The combined treatment did not increase the emission of VSCs. The application of sulphur and T. thioparus 1904 may help to control the odour of compost. Copyright © 2017. Published by Elsevier Ltd.

Optimization of digestion parameters for analysing the total sulphur of mine tailings by inductively coupled plasma optical emission spectrometry.

Science.gov (United States)

Alam, Raquibul; Shang, Julie Q; Cheng, Xiangrong

2012-05-01

The oxidation of sulphidic mine tailings and consequent acid generation poses challenges for the environment. Accurate and precise analysis of sulphur content is necessary for impact assessment and management of mine tailings. Here, the authors aim at developing a rapid and easy digestion procedure, which may analyse and measure the total amount of sulphur in mine tailings by using inductively coupled plasma. For evaluating effects of several variables, the researchers used a univariate (analysis of variance (ANOVA)) strategy and considered factors such as composition of the acid mixture, heating time, and refluxing device to optimize the performance. To do the experiment, the researchers have used two certified reference materials (KZK-1 and RTS-2) and samples of tailings from Musselwhite mine. ANOVA result shows that heating time is the most influencing factor on acid digestion of the reference materials whereas in case of a digestion of tailings sample, hydrochloric acid proved to be the most significant parameter. Satisfactory results between the measured and referenced values are found for all experiments. It is found that the aqua regia (1 ml HNO(3) + 3 ml HCl) digestion of 0.1 g of samples after only 40 min of heating at 95°C produced fast, safe, and accurate analytical results with a recovery of 97% for the selected reference materials.

Sulphur in the Sculptor dwarf spheroidal galaxy. Including NLTE corrections

NARCIS (Netherlands)

Skúladóttir, Á.; Andrievsky, S. M.; Tolstoy, E.; Hill, V.; Salvadori, S.; Korotin, S. A.; Pettini, M.

In Galactic halo stars, sulphur has been shown to behave like other α-elements, but until now, no comprehensive studies have been done on this element in stars of other galaxies. Here, we use high-resolution ESO VLT/FLAMES/GIRAFFE spectra to determine sulphur abundances for 85 stars in the Sculptor

Sulphur in the metal poor globular cluster NGC 6397

Science.gov (United States)

Koch, A.; Caffau, E.

2011-10-01

Sulphur (S) is a non-refractory α-element that is not locked into dust grains in the interstellar medium. Thus no correction to the measured, interstellar sulphur abundance is needed and it can be readily compared to the S content in stellar photospheres. Here we present the first measurement of sulphur in the metal poor globular cluster (GC) NGC 6397, as detected in a MIKE/Magellan high signal-to-noise, high-resolution spectrum of one red giant star. While abundance ratios of sulphur are available for a larger number of Galactic stars down to an [Fe/H] of ~ -3.5 dex, no measurements in globular clusters more metal poor than -1.5 dex have been reported so far. We find aNLTE, 3-D abundance ratio of [S/Fe] = +0.52 ± 0.20 (stat.) ± 0.08 (sys.), based on theS I, Multiplet 1 line at 9212.8 Å. This value is consistent with a Galactic halo plateau as typical of other α-elements in GCs and field stars, but we cannot rule out its membership with a second branch of increasing [S/Fe] with decreasing [Fe/H], claimed in the literature, which leads to a large scatter at metallicities around - 2 dex. The [S/Mg] and [S/Ca] ratios in this star are compatible with a Solar value to within the (large) uncertainties. Despite the very large scatter in these ratios across Galactic stars between literature samples, this indicates that sulphur traces the chemical imprints of the other α-elements in metal poor GCs. Combined with its moderate sodium abundance ([S/Na]NLTE = 0.48), the [S/Fe] ratio in this GC extends a global, positive S-Na correlation that is not seen in field stars and might indicate that proton-capture reactions contributed to the production of sulphur in the (metal poor) early GC environments. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

Integrated laboratory scale demonstration experiment of the hybrid sulphur cycle and preliminary scale-up

International Nuclear Information System (INIS)

Leybros, J.; Rivalier, P.; Saturnin, A.; Charton, S.

2010-01-01

The hybrid sulphur cycle is today one of the most promising processes to produce hydrogen on a massive scale within the scope of high temperature nuclear reactors development. Thus, the Fuel Cycle Technology Department at CEA Marcoule is involved in studying the hybrid sulphur process from a technical and economical performance standpoint. Based on mass and energy balance calculations, a ProsimPlus TM flow sheet and a commercial plant design were prepared. This work includes a study on sizing of the main equipment. The capital cost has been estimated using the major characteristics of main equipment based upon formulae and charts published in literature. A specific approach has been developed for electrolysers. Operational costs are also proposed for a plant producing 1000 mol/s H 2 . Bench scale and pilot experiments must focus on the electrochemical step due to limited experimental data. Thus, a pilot plant with a hydrogen capacity of 100 NL/h was built with the aim of acquiring technical and technological data for electrolysis. This pilot plant was designed to cover a wide range of operating conditions: sulphuric acid concentrations up to 60 wt.%, temperatures up to 100 deg. C and pressures up to 10 bar. New materials and structures recently developed for fuel cells, which are expected to yield significant performance improvements when applied to classical electrochemical processes, will be tested. All experiments will be coupled with phenomenological simulation tools developed jointly with the experimental programme. (authors)

Ultrasound-assisted extraction for total sulphur measurement in mine tailings

International Nuclear Information System (INIS)

Khan, Adnan Hossain; Shang, Julie Q.; Alam, Raquibul

2012-01-01

Highlights: ► We develop a total sulphur measuring procedure of mine tailings. ► Ultrasound is used in the sample pre-treatment process. ► Full factorial design is applied to identify the best level of effecting factors. - Abstract: A sample preparation method for percentage recovery of total sulphur (%S) in reactive mine tailings based on ultrasound-assisted digestion (USAD) and inductively coupled plasma-optical emission spectroscopy (ICP-OES) was developed. The influence of various methodological factors was screened by employing a two-level and three-factor (2 3 ) full factorial design and using KZK-1, a sericite schist certified reference material (CRM), to find the optimal combination of studied factors and %S. Factors such as the sonication time, temperature and acid combination were studied, with the best result identified as 20 min of sonication, 80 °C temperature and 1 ml of HNO 3 :1 ml of HCl, which can achieve 100% recovery for the selected CRM. Subsequently a fraction of the 2 3 full factorial design was applied to mine tailings. The percentage relative standard deviation (%RSD) for the ultrasound method is less than 3.0% for CRM and less than 6% for the mine tailings. The investigated method was verified by X-ray diffraction analysis. The USAD method compared favorably with existing methods such as hot plate assisted digestion method, X-ray fluorescence and LECO™-CNS method.

Preparation of acid deficient solutions of uranyl nitrate and thorium nitrate by steam denitration

International Nuclear Information System (INIS)

Yamagishi, Shigeru; Takahashi, Yoshihisa

1996-01-01

Acid deficient heavy metal (HM) nitrate solutions are often required in the internal gelation processes for nuclear fuel fabrication. The stoichiometric HM-nitrate solutions are needed in a sol-gel process for fuel fabrication. A method for preparing such nitrate solutions with a controlled molar ratio of nitrate/metal by denitration of acid-excess nitrate solutions was developed. The denitration was conducted by bubbling a nitrate solution with a mixture of steam+Ar. It was found that steam was more effective for the denitration than Ar. The acid deficient uranyl nitrate solution with nitrate/U=1.55 was yielded by steam bubbling, while not by only Ar bubbling. As for thorium nitrate, acid deficient solutions of nitrate/Th≥3.1 were obtained by steam bubbling. (author)

Distribution of sulphur and trace elements in peat. [Literature survey with some additional sulphur analyses

Energy Technology Data Exchange (ETDEWEB)

Huttunen, S; Karhu, M

1981-01-01

A survey on the literature and contemporary research was made on peat sulphur and trace element studies. Marked variance between different peatlands and peat types has been noted. The available information is still inadequate for generalizations or statistical analysis mainly due to methodological variations and temporal and spatial variations in results. At the moment, the criteria applied in peatland inventories and evaluations are inadequate with respect to peat quality determinations. To some extent the quality of fuel peat should be determined in a mire inventory prior to peatland utilization. The areas over sulphide clay and some sulphate depositions may considerably increase the peat sulphur content. A proposal has been made to include the sulphur content monitoring in the cases where it exceeds 0.3 per cent. The trace elements may also bring about an increase in peat emissions if the deepest peat layers or polluted layers are burnt. The most important elements in this respect are Al, Fe, Mn, Pb, Zn, V, Ni, Hg, Cu, Cr, as well as As and U. The first ten because of the relatively high concentrations and last two because of pollution or toxocity and ore deposit factors. The peat hydrogen ion concentration has a positive correlation with copper and vanadium. The correlation is positive with the cobalt and nickel contents when the pH is low, and negative at a higher pH. A general peat type correlation shows maximum trace element contents in basal Carex peats with subsoil effects. The peat ash content and the Ti, Pb, V, Cr, Ni and S contents have positive correlations.

Sulphur loading of respirable and inhalable dust at a platinum smelter / Swanepoel J.D.

OpenAIRE

Swanepoel, Johannes Deon.

2012-01-01

The contribution that sulphur, in the form of sulphates, has on ill health is still a focal point of many a study, especially in environmental studies depicting the effects that particulate air pollution has on health. Although the implication of sulphur on particulate matter is not yet well defined, numerous studies do state that the presence of sulphur on particulate matter contributes to poor health. Sulphur adhered to dust has been associated with cardiovascular mortality and the ability ...

Indium sulfide precipitation from hydrochloric acid solutions of calcium and sodium chlorides

International Nuclear Information System (INIS)

Kochetkova, N.V.; Bayandina, Yu.E.; Toptygina, G.M.; Shepot'ko, A.O.

1988-01-01

The effect of precipitation duration, acid concentration, indium complexing with chloride ions on the process of indium sulfide chemical precipitation in hydrochloric acid solutions, precipitate composition and dispersity are studied. It is established that indium sulfide solubility increases in solutions with acid concentration exceeding 0.40-0.45 mol/l. Calcium and indium chloride addition to diluted hydrochloric solutions greatly increases the solubility of indium sulfide. The effect of calcium chloride on In 2 S 3 solubility is higher than that of sodium chloride

Muonium states and dynamics in phosphorus and sulphur

International Nuclear Information System (INIS)

Cox, S.F.J.; Cottrell, S.P.; Hopkins, G.A.; Kay, M.; Pratt, F.L.

1997-01-01

The various states formed by positive muons implanted into phosphorus and sulphur have been characterized as a model for interstitial hydrogen, of which little is known in these elements. Repolarization studies reveal muonium-like states in each case, giving estimates of the hyperfine parameters and, for sulphur at least, an indication of the coexistence of a molecular radical state. The longitudinal-field relaxation functions suggest conversion of the paramagnetic states to diamagnetic, i.e. ionization or chemical reaction, in competition with strong spin-lattice relaxation

Sulphur levels in saliva as an estimation of sulphur status in cattle: a validation study

NARCIS (Netherlands)

Dermauw, V.; Froidmont, E.; Dijkstra, J.; Boever, de J.L.; Vyverman, W.; Debeer, A.E.; Janssens, G.P.J.

2012-01-01

Effective assessment of sulphur (S) status in cattle is important for optimal health, yet remains difficult. Rumen fluid S concentrations are preferred, but difficult to sample under practical conditions. This study aimed to evaluate salivary S concentration as estimator of S status in cattle.

Comparative study on sulphur reduction from heavy petroleum - Solvent extraction and microwave irradiation approach

Energy Technology Data Exchange (ETDEWEB)

Mohammed, Abdullahi Dyadya; Isah, Abubakar Garba; Umaru, Musa; Ahmed, Shehu [Department of Chemical Engineering, Federal University of Technology, P.M.B 65, Minna (Nigeria); Abdullahi, Yababa Nma [National Petroleum Investment Management Services (Nigeria National Petroleum Corporation), Lagos (Nigeria)

2012-07-01

Sulphur- containing compounds in heavy crude oils are undesirable in refining process as they affect the quality of the final product, cause catalyst poisoning and deactivation in catalytic converters as well as causing corrosion problems in oil pipelines, pumps and refining equipment aside environmental pollution from their combustion and high processing cost. Sulphur reduction has being studied using microwave irradiation set at 300W for 10 and 15minutes and oxidative- solvent extraction method using n- heptane and methanol by 1:1, 1:2 and 1:3 crude- solvent ratios after being oxidized with hydrogen peroxide, H2O2 oxidants. Percentage sulphur removal with n- heptane solvent by 1:1 and 1:2 are 81.73 and 85.47%; but extraction using methanol by different observed ratios gave less sulphur reduction. Indeed when microwave irradiated at 300W for 10 and 15minutes, 53.68 and 78.45% reduction were achieved. This indicates that microwave irradiation had caused oxidation by air in the oven cavity and results to formation of alkyl radicals and sulphoxide from sulphur compound in the petroleum. The prevailing sulphur found in the crude going by FT-IR results is sulphides which oxidized to sulphoxide or sulphones. It is clear that sulphur extraction with heptane is more efficient than microwave irradiation but economically due to demands for solvent and its industrial usage microwave irradiation can serve as alternative substitute for sulphur reduction in petroleum. Sulphur reduction by microwave radiation should be up- scaled from laboratory to a pilot plant without involving extraction column in the refining.

Sulphur and nitrogen supply - soil acidification and the absorption of nutrients in plants; Svovel og nitrogentilfoersel - jordforsuring og plantenes naeringstilgang

Energy Technology Data Exchange (ETDEWEB)

Abrahamsen, G

1996-01-01

Ecologically, soil is of the greatest interest as a growth medium for plants, and which affects the quality of ground water and surface water. In this connection, the paper looks upon how the increased deposition of sulphur, nitrogen and hydrogen ions affect the quality of soil as a growth medium for plants. Topics cover: Interaction between soil and plants, effects of acid rain in soil, and the effects of acid rain on plants. 11 refs., 1 tab.

78 FR 64526 - Information Collection Activities: Sulphur Operations; Submitted for Office of Management and...

Science.gov (United States)

2013-10-29

...: Sulphur Operations; Submitted for Office of Management and Budget (OMB) Review; Comment Request ACTION: 30... paperwork requirements in the regulations under Subpart P, Sulphur Operations. This notice also provides the..., Currently Under Review). SUPPLEMENTARY INFORMATION: Title: 30 CFR 250, Subpart P, Sulphur Operations. OMB...

Mechanism of the extraction of nitric acid and water by organic solutions of tertiary alkyl-amines; Mecanisme d'extraction de l'acide nitrique et de l'eau par les solutions organiques d'alcoylamines tertiaires

Energy Technology Data Exchange (ETDEWEB)

Gourisse, D

1966-06-01

The micellar aggregation of tri-alkyl-ammonium nitrates in low polarity organic solvents has been verified by viscosity, conductivity and sedimentation velocity measurements. The aggregation depends upon the polarity of solvent, the length of the alkyl radicals and the organic concentration of the various constituents (tri-alkyl-ammonium nitrate, tri-alkyl-amine, nitric acid, water). The amine salification law has been established and the excess nitric acid and water solubilities in the organic solutions have been measured. Nitric acid and water are slightly more soluble in micellar organic solutions than in molecular organic solutions. A description of excess nitric acid containing tri-alkyl-ammonium nitrate solutions is proposed. (author) [French] Mecanisme d'extraction de l'acide nitrique et de l'eau par les solutions organiques d'alcoylamines tertiaires. L'agregation micellaire des nitrates de trialcoylammonium dans les solvants peu polaires a ete verifiee par viscosimetrie, conductimetrie et ultracentrifugation des solutions organiques. L'agregation depend de la polarite du solvant, de la longueur des radicaux alcoyle, et des concentrations des differents constituants de la solution organique (nitrate de trialcoylammonium, alcoylamine tertiaire, acide nitrique, eau). La loi de salification de l'amine a ete determinee et les solubilites de l'acide nitrique en exces et de l'eau dans les solutions organiques ont ete mesurees. L'acide nitrique et l'eau sont legerement plus solubles dans les organiques micellaires que dans les solutions organiques moleculaires. Une description des solutions de nitrate de trialcoylammonium contenant de l'acide nitrique en exces est proposee. (auteur)

Determination of free nitric acid in uranyl nitrate solution

International Nuclear Information System (INIS)

Mayankutty, P.C.; Ravi, S.; Nadkarni, M.N.

1981-01-01

Potentiometric titration of uranyl nitrate solution with sodium hydroxide exhibits two peaks. The first peak characterises the following reaction, UO 2 (C 2 O 4 )+NaOH Na[UO 2 (C 2 O 4 )(OH)]. This reaction, indicating the partial hydrolysis of uranyl oxalate complex, appears to be complete at pH9. If the titration is carried out to this end-point pH, the total alkali consumed can be equated to the sum of uranium content and the free acidity present in the sample volume. Based on this, a method was standardised to determine the free acidity in uranyl nitrate solution. The sample, taken in a solution of potassium oxalate previously adjusted to pH9, is titrated to this pH with standard sodium hydroxide. The free acidity in the sample can be computed by subtracting the alkali reacted with uranium from the total alkali consumed. Analyses of several synthetic samples containing uranium and nitric acid in a wide range of combinations indicate that the free acidity can be accurately determined by this method, if uranium concentration in the sample is known. The results are compared to those obtained by two other widely used methods, viz., (i) titration of pH7 in the presence of neutral potassium oxalate to suppress hydrolysis and (ii) separation of hydrolyzable ions on a cationic resin and alkali titration of the free acid released. The advantages of and the precision obtained with the present method over the above two methods are discussed. (author)

Ball-milling synthesis of ZnO@sulphur/carbon nanotubes and Ni(OH)_2@sulphur/carbon nanotubes composites for high-performance lithium-sulphur batteries

International Nuclear Information System (INIS)

Gu, Xingxing; Tong, Chuan-jia; Wen, Bo; Liu, Li-min; Lai, Chao; Zhang, Shanqing

2016-01-01

Highlights: • Metal oxides or hydroxides coating sulfur-based composite are successfully prepared. • Large-scale synthesis can be realized via the facile wet ball-milling strategy. • Density functional theory (DFT) calculation is applied to calculate adsorption energy. • ZnO exhibits a higher adsorption energy for Li_2S_8 than that Ni(OH)_2. • ZnO@sulphur/carbon nanotubes composite show excellent cycle and discharge performance. - Abstract: Zinc oxide wrapped sulphur/carbon nanotubes (ZnO@S/CNT) and nickel hydroxide wrapped sulphur/carbon nanotubes (Ni(OH)_2@S/CNT) nanocomposites are prepared using a simple, low cost and scalable ball-milling method. As the cathodes in Li-S batteries, the as-prepared ZnO@S/CNT composite illustrates a superior high initial capacity of 1663 mAh g"−"1 at a charge/discharge rate of 160 mA g"−"1, and maintains a reversible capacity at approximately 942 mAh g"−"1 after 70 cycles. While for Ni(OH)_2@S/CNT composites, its initial capacity is also as high as 1331 mAh g"−"1, but a poorer cycling stability is presented. When the charge/discharge current is increased to 1600 mA g"−"1, a high reversible capacity of 698 mAh g"−"1 after 200 cycles still can be obtained for the ZnO@S/CNT composite, far better than that of Ni(OH)_2@S/CNT composites. The better cycling performance and high discharge capacity can be attributed to the strong interactions between ZnO and S_x"2"− species, which is verified by the density functional theory (DFT) calculation result that the ZnO exhibits a higher adsorption energy for Li_2S_8 than the Ni(OH)_2.

Mesoporous titanium-manganese dioxide for sulphur mustard and soman decontamination

Energy Technology Data Exchange (ETDEWEB)

Stengl, Vaclav, E-mail: stengl@iic.cas.cz [Department of Solid State Chemistry, Institute of Inorganic Chemistry AS CR v.v.i., 250 68 Rez (Czech Republic); Bludska, Jana [Department of Solid State Chemistry, Institute of Inorganic Chemistry AS CR v.v.i., 250 68 Rez (Czech Republic); Oplustil, Frantisek; Nemec, Tomas [Military Technical Institute of Protection Brno, Veslarska 230, 628 00 Brno (Czech Republic)

2011-11-15

Highlights: {yields} New nano-dispersive materials for warfare agents decontamination. {yields} 95% decontamination activities for sulphur mustard. {yields} New materials base on titanium and manganese oxides. -- Abstract: Titanium(IV)-manganese(IV) nano-dispersed oxides were prepared by a homogeneous hydrolysis of potassium permanganate and titanium(IV) oxo-sulphate with 2-chloroacetamide. Synthesised samples were characterised using Brunauer-Emmett-Teller (BET) surface area and Barrett-Joiner-Halenda porosity (BJH), X-ray diffraction (XRD), infrared spectroscopy (IR), and scanning electron microscopy (SEM). These oxides were taken for an experimental evaluation of their reactivity with sulphur mustard (HD or bis(2-chloroethyl)sulphide) and soman (GD or (3,3'-dimethylbutan-2-yl)-methylphosphonofluoridate). Mn{sup 4+} content affects the decontamination activity; with increasing Mn{sup 4+} content the activity increases for sulphur mustard and decreases for soman. The best decontamination activities for sulphur mustard and soman were observed for samples TiMn{sub 3}7 with 18.6 wt.% Mn and TiMn{sub 5} with 2.1 wt.% Mn, respectively.

Calorimetric study of interaction of barium hydroxide with diluted solutions of hydrofluoric acid

International Nuclear Information System (INIS)

Kurbanov, A.R.; Sharipov, D.Sh.

1993-01-01

Present article is devoted to calorimetric study of interaction of barium hydroxide with diluted solutions of hydrofluoric acid. The calorimetric study of interaction of barium hydroxide with diluted solutions of hydrofluoric acid was carried out in order to determine the thermal effects of reactions. The results of interaction of Ba(OH) 4 ·8H 2 O with 5, 10, and 20% solution of hydrofluoric acid were considered.

Ionizing radiation induced degradation of salicylic acid in aqueous solution

Science.gov (United States)

Albarrán, Guadalupe; Mendoza, Edith

2018-06-01

The radiation-induced degradation of salicylic acid (SA-) in aqueous solutions (1.0 and 0.1 mmol dm-3) saturated with N2O or air or without oxygen were studied. Irradiation was carried out using a cobalt-60 source. With a 1 mmol dm-3 solution saturated with N2O a seemingly total degradation occurred at about 18 kGy, although small quantities of 2,3-dihydroxybenzoic acid, catechol and 2,5-dihydroxybenzoic acid were present at that dose at concentrations of 67, 22 and 6 μmol dm-3 respectively. Under air and when free oxygen, the three radiolytic products were present at 18.54 kGy while SA- was destroyed only to 90% and 62%, respectively. In the case of 0.1 mmol dm-3 SA- solutions, the acid was degraded at 3.5 kGy if the solution contained N2O, at 5.8 kGy in air and at 7 kGy without oxygen. The concentration of the radiolytic products increased with increasing dose and after a maximum they decreased. The oxidation was followed by measuring the chemical oxygen demand; the slopes were 0.48 and 0.11, 0.21 and 0.07, 0.15 and 0.03 mmol dm-3 kGy-1 for 1.0 and 0.10 mmol dm-3 solutions saturated with N2O or air or without oxygen, respectively.

Adsorption of copper from the sulphate solution of low copper contents using the cationic resin Amberlite IR 120

International Nuclear Information System (INIS)

Jha, Manis Kumar; Nghiem Van Nguyen; Lee, Jae-chun; Jeong, Jinki; Yoo, Jae-Min

2009-01-01

In view of the increasing importance of the waste processing and recycling to meet the strict environmental regulations, the present investigation reports an adsorption process using the cationic exchanger Amberlite IR 120 for the recovery/removal of copper from the synthetic sulphate solution containing copper ≤0.7 mg/mL similar to the CMP waste effluent of electronic industry. Various process parameters, viz. contact time, solution pH, resin dose, and acid concentration of eluant were investigated for the adsorption of copper from the effluents. The 99.99% copper was found to be adsorbed from the sulphate solution containing copper 0.3-0.7 mg/mL of solution (feed pH 5) at A/R ratio 100 and eq. pH 2.5 in contact time 14 min. The mechanism for the adsorption of copper was found to follow Langmuir isotherm and second order rate. From the loaded organic, copper was eluted effectively by 1.8 M sulphuric acid at A/R ratio 25. The raffinate obtained after the recovery copper could be disposed safely without affecting the environment.

Interaction between Al3+ and acrylic acid and polyacrylic acid in acidic aqueous solution: a model experiment for the behavior of Al3+ in acidified soil solution.

Science.gov (United States)

Etou, Mayumi; Masaki, Yuka; Tsuji, Yutaka; Saito, Tomoyuki; Bai, Shuqin; Nishida, Ikuko; Okaue, Yoshihiro; Yokoyama, Takushi

2011-01-01

From the viewpoint of the phytotoxicity and mobility of Al(3+) released from soil minerals due to soil acidification, the interaction between Al(3+) and acrylic acid (AA) and polyacrylic acid (PAA) as a model compound of fulvic acid was investigated. The interaction was examined at pH 3 so as to avoid the hydrolysis of Al(3+). The interaction between Al(3+) and AA was weak. However, the interaction between Al(3+) and PAA was strong and depended on the initial (COOH in PAA)/Al molar ratio (R(P)) of the solution. For the range of 1/R(P), the interaction between Al(3+) and PAA can be divided into three categories: (1) 1:1 Al-PAA-complex (an Al(3+) combines to a carboxyl group), (2) intermolecular Al-PAA-complex (an Al(3+) combines to more than 2 carboxyl groups of other Al-PAA-complexes) in addition to the 1:1 Al-PAA-complex and (3) precipitation of intermolecular complexes. In conclusion, R(P) is an important factor affecting the behavior of Al(3+) in acidic soil solution.

Measuring and modeling aqueous electrolyte/amino-acid solutions with ePC-SAFT

International Nuclear Information System (INIS)

Held, Christoph; Reschke, Thomas; Müller, Rainer; Kunz, Werner; Sadowski, Gabriele

2014-01-01

Highlights: • Amino-acid solubilities and osmotic coefficients in ternary solutions containing one amino acids and one salt measured. • Weak salt influence on amino-acid solubilities except for salts containing Mg [2+] or NO 3 [−] (salting-in behavior). • Osmotic coefficients dominated by the solute with the highest molality. • Amino-acid solubilities and osmotic coefficients predicted reasonably with ePC-SAFT with deviations of 3.7% and 9.3%. • Predictions based on pure-component parameters for ions and amino acids using no ion/amino-acid fitting parameters. -- Abstract: In this work thermodynamic properties of electrolyte/amino acid/water solutions were measured and modeled. Osmotic coefficients at 298.15 K were measured by means of vapor-pressure osmometry. Amino-acid solubility at 298.15 K was determined gravimetrically. Considered aqueous systems contained one of the four amino acids: glycine, L-/DL-alanine, L-/DL-valine, and L-proline up to the respective amino-acid solubility limit and one of 13 salts composed of the ions Li + , Na + , K + , NH 4 + , Cl − , Br − , I − , NO 3 − , and SO 4 2− at salt molalities of 0.5, 1.0, and 3.0 mol · kg −1 , respectively. The data show that the salt influence is more pronounced on osmotic coefficients than on amino-acid solubility. The electrolyte Perturbed-Chain Statistical Association Theory (ePC-SAFT) was applied to model thermodynamic properties in aqueous electrolyte/amino-acid solutions. In previous works, this model had been applied to binary salt/water and binary amino acid/water systems. Without fitting any additional parameters, osmotic coefficients and amino-acid solubility in the ternary electrolyte/amino acid/water systems could be predicted with overall deviations of 3.7% and 9.3%, respectively, compared to the experimental data

Immobilization of citric acid solutions in portland cement

International Nuclear Information System (INIS)

Lopes, Valdir M.; Rzyski, Barbara M.

1997-01-01

Decontamination processes by using citric acid on certain items used in the nuclear area, can result in large volumes of liquid wastes with low activity or effluents, contaminated with uranium and some elements dangerous to the environment. A great number of installations that have decontamination processes adopt the zero discharge philosophy. So, one of the forms to isolate the solutions is by reducing its volume through the evaporation process. The generated must can be neutralized and encapsulated or immobilized in Portland cement. This work propose a chemical technique to destroy the citric acid in the decontamination solutions instead of neutralization and, depending on the installation convenience, a direct cement immobilization of these solutions or of the evaporation mud. The results obtained in this work involve data about the workability, setting time and mechanical resistance, after 28 days of sealed cure, for samples with water-cement ratios of 4, 0.5 and 0.6, by weight. (author). 5 refs., 2 tabs

Effect of simulated acid rain (sar) on some morphochemical aspects of mash (vigna mungo l.)

International Nuclear Information System (INIS)

Imran, H.A.; Hussain, M.; Hussain, S.

2014-01-01

The studies were conducted to evaluate the effect of simulated acid rain (SAR) at early plant growth on some morphochemical characters of two varieties of Mash (Vigna mungo L.) namely Mash 97 and Var. 95009. Different pH values were made by using H/sub 2/SO/sub 4/, HNO/sub 3/, and combination of both. The data revealed that low pH (3.5) of either sulphuric acid or the combination of H/sub 2/SO/sub 4/ and HNO/sub 3/ affected more severely at all parameters including number of leaves, shoot: root ratio, water contents of shoot and Potassium ion concentration. Whereas for a few parameters like plant height and number of branches the simulated acid rain of solution of pH 4.5 and 3.5 by using HNO/sub 3/ proved a bit better for plant growth, the root length was increased in case of SAR of solution of pH 3.5 by using H/sub 2/SO/sub 4/+HNO/sub 3/. Foliar application of SAR of solution of pH greater than 4.5 showed some improvement in crop growth due to fertilizer effect of solution's components. (author)

Determination of radiochemical purity and pharmacokinetic parameters of sup(99m)Tc-sulphur colloid and sup(99m)Tc-tin colloid

International Nuclear Information System (INIS)

Jovanovic, V.; Konstantinovska, D.; Milivojevic, K.; Bzenic, J.

1981-01-01

Labelling yield and radiochemical purity, higher than 95%, of sup(99m)Tc-colloid preparations were determined by using the paper chromatography method. Less than 3% of labelled citric acid, added to the preparation as a buffer solution, has been found in sup(99m)Tc-sulphur colloid. High radiochemical purity and optimum size of colloid particles has also been proved by biodistribution studies on experimental animals. The analysis performed has shown that more than 50% of sup(99m)Tc-colloid preparations excreted by urine is sup(99m)TcO - , the remaining past 50% being protein bound sup(99m)Tc. Biological half-time of excretion of the fast phase is the same for both preparations, i.e. 10 min, while for the slow component it is 120 min in sup(99m)Tc-S-colloid and 160 min in sup(99m)Tc-Sn colloid. (orig.) [de

Regional modelling of anthropogenic sulphur in Southeast Asia

Science.gov (United States)

Engardt, M.; Leong, C. P.

A co-operative research project between the Malaysian Meteorological Service (MMS) and the Swedish Meteorological and Hydrological Institute (SMHI) focussing on the usage of an atmospheric transport and chemistry model, has just been initiated. Here, we describe the main features of the dispersion model and discuss a first set of calculations in light of available measurements of sulphuric species in Southeast Asia. According to our results, anthropogenic sulphur concentrations and depositions are particularly high near the large cities of the region, around a metal smelter in the southern Philippines, and in a region extending from northern Vietnam into southeastern China. These areas coincide with the high-emissions regions of Southeast Asia and we tentatively conclude that regional transport of acidifying species is not as far-reaching as in the mid-latitudes. From our calculations, and from supporting measurements we conclude that most of rural Southeast Asia is not yet severely affected by anthropogenic sulphur, but given the rapid rate of economical development in this region the situation may deteriorate quickly. Areas that are particularly at risk include the large cities, northern Vietnam, most of central Thailand, most of peninsular Malaysia, eastern Sumatra and parts of Java, all of which receive total-sulphur depositions in excess of 0.5 g S m -2 yr -1. Our model simulates sulphate in precipitation in accordance with measurements, but it has a tendency to overestimate atmospheric SO 2. It remains to be investigated whether this is a problem in the model formulation or a result of unrepresentative sampling. An immediate continuation of this study should be performed with higher spatial resolution than the currently used 100×100 km 2. Other imperfections in this model study, which should be addressed in future work, include parameterised vertical transport in deep convective clouds, the influence of natural emissions (primarily from volcanoes) on the

Cacotheline as an oxidimetric reagent. Determination of Sn(II), Cu(I), Ti(III), Fe(II), V(II) and V(III)

International Nuclear Information System (INIS)

Nemani Murty, K.; Yedluri Rao, P.; Geddada Chalam, K.

1982-01-01

Sn(II), Ti(III), Cu(I),Fe(II), V(III) and V(II) can be titrated potentiometrically with cacotheline in 1-4 M hydrochloric acid, 0.5-2 M hydrochloric acid, 0.5-1.5 M sulphuric acid in presence of 4 ml of 10% EDTA solution in a total volume of 50 ml, 9-10 M phosphoric acid, 4-8 M acetic acid and 3-8 M acetic acid respectively. Cacotheline can be used for the assay of tin plate and solder. The cacotheline undergoes a 2-electron reduction reaction. A cacotheline solution (0.005 M) in 0.02 M hydrochloric acid is fairly stable for several months. The conditional redox potentials of cacotheline have been determined in sulphuric, phosphoric and acetic acid medium. (Author)

Corrosion behavior of niobium coated 304 stainless steel in acid solution

Energy Technology Data Exchange (ETDEWEB)

Pan, T.J., E-mail: tjpan@cczu.edu.cn [School of Material Science and Engineering, Jiangsu Collaborative Innovation Center for Photovolatic Science and Engineering, Changzhou University, Changzhou 213164 (China); Jiangsu Key Laboratory of Material Surface Technology, Changzhou 213164 (China); Chen, Y.; Zhang, B. [School of Material Science and Engineering, Jiangsu Collaborative Innovation Center for Photovolatic Science and Engineering, Changzhou University, Changzhou 213164 (China); Hu, J. [School of Material Science and Engineering, Jiangsu Collaborative Innovation Center for Photovolatic Science and Engineering, Changzhou University, Changzhou 213164 (China); Jiangsu Key Laboratory of Material Surface Technology, Changzhou 213164 (China); Li, C. [Light Industry College of Liaoning University, Shenyang 110036 (China)

2016-04-30

Highlights: • The Nb coating produced by HEMAA offers good protection for 304SS in acid solution. • The coating increases corrosion potential and induces decrease of corrosion rate. • The protection of coating is ascribed to the stability of Nb in acid solution. - Abstract: The niobium coating is fabricated on the surface of AISI Type 304 stainless steel (304SS) by using a high energy micro arc alloying technique in order to improvecorrosion resistance of the steel against acidic environments. The electrochemical corrosion resistance of the niobium coating in 0.7 M sulfuric acid solutions is evaluated by electrochemical impedance spectroscopy, potentiodynamic polarization and the open circuit potential versus time. Electrochemical measurements indicate that the niobium coating increases the free corrosion potential of the substrate by 110 mV and a reduction in the corrosion rate by two orders of magnitude compared to the substrate alone. The niobium coating maintains large impedance and effectively offers good protection for the substrate during the long-term exposure tests, which is mainly ascribed to the niobium coating acting inhibiting permeation of corrosive species. Finally, the corresponding electrochemical impedance models are proposed to elucidate the corrosion resistance behavior of the niobium coating in acid solutions.

Corrosion behavior of niobium coated 304 stainless steel in acid solution

International Nuclear Information System (INIS)

Pan, T.J.; Chen, Y.; Zhang, B.; Hu, J.; Li, C.

2016-01-01

Highlights: • The Nb coating produced by HEMAA offers good protection for 304SS in acid solution. • The coating increases corrosion potential and induces decrease of corrosion rate. • The protection of coating is ascribed to the stability of Nb in acid solution. - Abstract: The niobium coating is fabricated on the surface of AISI Type 304 stainless steel (304SS) by using a high energy micro arc alloying technique in order to improvecorrosion resistance of the steel against acidic environments. The electrochemical corrosion resistance of the niobium coating in 0.7 M sulfuric acid solutions is evaluated by electrochemical impedance spectroscopy, potentiodynamic polarization and the open circuit potential versus time. Electrochemical measurements indicate that the niobium coating increases the free corrosion potential of the substrate by 110 mV and a reduction in the corrosion rate by two orders of magnitude compared to the substrate alone. The niobium coating maintains large impedance and effectively offers good protection for the substrate during the long-term exposure tests, which is mainly ascribed to the niobium coating acting inhibiting permeation of corrosive species. Finally, the corresponding electrochemical impedance models are proposed to elucidate the corrosion resistance behavior of the niobium coating in acid solutions.

Chelated Nitrogen-Sulphur-Codoped TiO2: Synthesis, Characterization, Mechanistic, and UV/Visible Photocatalytic Studies

Directory of Open Access Journals (Sweden)

Hayat Khan

2017-01-01

Full Text Available This study presents in detail the physicochemical, photoluminescent, and photocatalytic properties of carboxylic acid chelated nitrogen-sulphur-codoped TiO2. From the Fourier transform infrared spectroscopic study, it was revealed that the formate group formed bidentate bridging linkage while the acetate group coordinated in a bidentate chelating mode with a titanium precursor. In compliance with X-ray diffraction data, the anatase to rutile transformation temperature was extended due to carboxylic acid chelation and NS codoping. Raman analysis indicated four Raman peaks at 146, 392, 512, and 632 cm−1 for the precalcined chelated TiO2; on incorporation with NS dopants, an increase in Raman intensity for these peaks was recorded, indicating the structure stability of the anatase phase. Furthermore, X-ray photoelectron spectroscopic study revealed the presence of anionic doping of nitrogen and cationic doping of sulphur in the lattice of TiO2. When evaluating the UV-visible photodegradation rate of 4-chlorophenol, the modified TiO2 (NS0.06-TFA showed the highest photocatalytic activity. In connection with the activity tests, several scavenger agents were employed to elucidate the significance of the different reactive oxidizing species during the photocatalytic process. Moreover, the transfer pathways of photogenerated carriers and the photocatalytic reaction mechanism of modified TiO2 were also explained in detail.

Method for separation of Cs from acid solution dissolving radionuclides and microanalysis of solution with ICP-AES

International Nuclear Information System (INIS)

Kanazawa, Toru; Hidaka, Akihide; Kudo, Tamotsu; Nakamura, Takehiko; Fuketa, Toyoshi

2004-06-01

The VEGA (Verification Experiments of radionuclides Gas/Aerosol release) program is being performed at JAERI to understand mechanisms of radionuclides release from irradiated fuel during severe accidents. As a part of evaluation in the program, the mass balances of released and deposited FP (Fission Products) onto the test apparatus are estimated from gamma ray measurement for acid solution leached from the apparatus, but short-life nuclides are difficult to be measured because those in the VEGA fuel have been mostly depleted due to cooling for several years. Moreover, the radionuclides without emitting gamma rays and very small quantity of elements cannot be quantified by gamma ray measurement. Therefore, a microanalysis by ICP-AES (Inductively Coupled Plasma - Atomic Emission Spectrometry) for the acid solution leached from VEGA apparatuses is being applied to evaluate the released and deposited masses for those elements. Since Cs-134 and -137, which are major FP dissolved in the solution, have high intensity of gamma ray spectrum, they have to be removed from the solution before the microanalysis in order to avoid contamination of ICP system and to decrease exposure to gamma ray. In this report, methods for separation of Cs from acid solution were reviewed and the applicability of them to the ICP-AES analysis was discussed. The method for Cs separation using the inorganic ion exchanger, AMP (Ammonium Molybdate Phosphate) was applied to the solutions of cold and hot test and the effectiveness was examined. The results showed that more than 99.9% of Cs could be removed from the test solutions, and once removed Sb by AMP was recovered by using a complexing agent such as citric acid. Next, the method was applied to an acid solution leached from VEGA-3 apparatus, and ICP-AES analysis was performed for it. The analysis showed that amount of U, Sr and Zr were successfully quantified. Most of elements to be analyzed were measurable except for Sb, Ag and Sn, although

Treatment of infectious skin defects or ulcers with electrolyzed strong acid aqueous solution.

Science.gov (United States)

Sekiya, S; Ohmori, K; Harii, K

1997-01-01

A chronic ulcer with an infection such as methicillin-resistant Staphylococcus aureus is hard to heal. Plastic and reconstructive surgeons often encounter such chronic ulcers that are resistant to surgical or various conservative treatments. We applied conservative treatment using an electrolyzed strong acid aqueous solution and obtained satisfactory results. The lesion was washed with the solution or soaked in a bowl of the solution for approximately 20 min twice a day. Fresh electrolyzed strong acid aqueous solution is unstable and should be stored in a cool, dark site in a sealed bottle. It should be used within a week after it has been produced. Here we report on 15 cases of infectious ulcers that were treated by electrolyzed strong acid aqueous solution. Of these cases, 7 patients were healed, 3 were granulated, and in 5, infection subsided. In most cases the lesion became less reddish and less edematous. Discharge or foul odor from the lesion was decreased. Electrolyzed strong acid aqueous solution was especially effective for treating a chronic refractory ulcer combined with diabetes melitus or peripheral circulatory insufficiency. This clinically applied therapy of electrolyzed strong acid aqueous solution was found to be effective so that this new therapeutic technique for ulcer treatment can now be conveniently utilized.

Study of free acidity determinations in aqueous solution; Etude des dosages d'acidite libre en solution aqueuse

Energy Technology Data Exchange (ETDEWEB)

Kergreis, A [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1966-04-01

The object of this work is the study of the principal methods which can be applied to the measurement of 'free' acidity. In the first part, we define the various types of acidity which can exist in aqueous solution; then, after having studied some hydrolysis reactions, we compare the value of the neutralisation pH of the hydrated cation and that of the precipitation of the hydroxide. In the second part we have started to study the determination of the acidity of an aqueous solution. After having rapidly considered the 'total' acidity determination, we deal with the problem of the 'free' acidity titration. We have considered in particular certain methods: extrapolation of the equivalent point, colorimetric titrations with or without a complexing agent, and finally the use of ion-exchange resins with mixed aqueous and solvent solutions. (author) [French] Le but de ce travail est l'etude des principales methodes de determination de l'acidite 'libre'. Dans une premiere partie nous avons defini les differentes sortes d'acidites pouvant exister en solution aqueuse, puis apres avoir etudie quelques reactions d'hydrolyse, nous avons compare la valeur de pH de neutralisation du cation hydrate et celle de precipitation de l'hydroxyde. Dans la seconde partie nous avons aborde l'etuce des dosages de l'acidite d'une solution aqueuse. Apres avoir envisage assez rapidement la determination de l'acidite 'totale', nous traitons du probleme du titrage de l'acidite 'libre'. Nous avons porte notre attention sur certaines methodes: extrapolation du point equivalent, titrimetrie colorimetrique avec ou sans complexant, et enfin utilisation des resines echangeuses d'ions en milieu aqueux et solvant mixte.

Sulphur management in onion (Allium cepa) cultivation in hills of Himachal Pradesh.

Science.gov (United States)

Jaggi, R C; Sharma, R K

2010-05-01

Field experiment were conducted at CSK HPKV Research Farm, Palampur during Rabi seasons of 2000-01 and 2001-02, to study the response of onion (Allium cepa var Patna red) at four sulphur levels (0, 15, 30 and 60 kg ha(-1)) applied through Gypsum and S95. The analysis was done to allocate the limited availability of sulphur for maximizing net profit over fertilizer cost. The results show that the dose of sulphur under its full availability is 43.02 kg ha(-1). But under its scarce availability the maximum benefit would occur when it is applied up to 32.11 kg ha(-1) followed by even distribution of fertilizer i.e. 20 kg ha(-1). The returns following sulphur application at these rates, would be Rs 69340, 73092 and 68700 ha(-1) respectively.

Growth behavior of anodic porous alumina formed in malic acid solution

Science.gov (United States)

Kikuchi, Tatsuya; Yamamoto, Tsuyoshi; Suzuki, Ryosuke O.

2013-11-01

The growth behavior of anodic porous alumina formed on aluminum by anodizing in malic acid solutions was investigated. High-purity aluminum plates were electropolished in CH3COOH/HClO4 solutions and then anodized in 0.5 M malic acid solutions at 293 K and constant cell voltages of 200-350 V. The anodic porous alumina grew on the aluminum substrate at voltages of 200-250 V, and a black, burned oxide film was formed at higher voltages. The nanopores of the anodic oxide were only formed at grain boundaries of the aluminum substrate during the initial stage of anodizing, and then the growth region extended to the entire aluminum surface as the anodizing time increased. The anodic porous alumina with several defects was formed by anodizing in malic acid solution at 250 V, and oxide cells were approximately 300-800 nm in diameter.

Photolysis of Periodate and Periodic Acid in Aqueous Solution

DEFF Research Database (Denmark)

Sehested, Knud; Kläning, U. K.

1978-01-01

The photochemistry of periodate and periodic acid in aqueous solution was studied (i) by quantum yield measurements at low light intensity (ii) by flash photolysis, and (iii) by photolysis of glassy samples at 77 K. The photochemical studies were supplemented with pulse radiolysis studies...... of aqueous periodate solutions and with kinetic studies using stopped-flow technique. In strongly alkaline solution the photodecomposition of periodate proceeds via formation of O– and IVI. At pH solution O3 P is formed in a small...

High pressure treatments accelerate changes in volatile composition of sulphur dioxide-free wine during bottle storage.

Science.gov (United States)

Santos, Mickael C; Nunes, Cláudia; Rocha, M Angélica M; Rodrigues, Ana; Rocha, Sílvia M; Saraiva, Jorge A; Coimbra, Manuel A

2015-12-01

The impact of high hydrostatic pressure (HHP) treatments on volatile composition of sulphur dioxide-free wines during bottle storage was studied. For this purpose, white and red wines were produced without sulphur dioxide (SO2) and, at the end of the alcoholic fermentation, the wines were pressurised at 500 MPa and 425 MPa for 5 min. Wine with 40 ppm of SO2 and a wine without a preservation treatment were used as controls. More than 160 volatile compounds, distributed over 12 chemical groups, were identified in the wines by an advanced gas chromatography technique. The pressurised wines contained a higher content of furans, aldehydes, ketones, and acetals, compared with unpressurised wines after 9 months of storage. The changes in the volatile composition indicate that HHP treatments accelerated the Maillard reaction, and alcohol and fatty acid oxidation, leading to wines with a volatile composition similar to those of faster aged and/or thermally treated wines. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effectiveness of Higher Fatty Acids C8, C10 and C12, Dimethyl Dicarbonate and Sulphur Dioxide for Inhibition of Re-fermentation and Malolactic Activities in Wine

Directory of Open Access Journals (Sweden)

Mojmír Baroň

2014-01-01

Full Text Available The issue of preventing the re-fermentation and protection against undesirable malolactic fermentation (MLF in order to safe content of acids in wine is very complicated. In this paper the saturated higher fatty acids (HFA – C8, C10 and C12, dimethyldicarbonate (DMDC and sulphur dioxide (SO2 were tested. The re-fermentation test showed the strongest inhibition power at ratio 2:8, 1:9 and 0:10 as C8:C10 acids – 65 days without re-fermentation. MLF experiments confirmed that addition of SO2 into the fermenting media causes rapid inhibition of lactic acid bacteria metabolic activity. Malic acid concentrations were proportionally decreasing during 6 days of experiment and at the end the content of this acid varied between 0.16 and 0.22 g/L, the only exception formed a variant with the addition of SO2 (1.57 g/L of malic acid. After calculation of the average consumption rate of malic acid, the results showed the inhibition power – SO2 (81.05% followed by variant of 40 mg/L mixture of HFA (40.76%, a variant of 200 mg/L of DMDC (31.98% and a variant of 20 mg/L mixture of HFA (12.59%. The addition of HFA can significantly reduce the dosage of other preservatives, especially SO2. Based on results, this method can be recommend in the production of wines with residual sugar and also wines made from over-mature material to prevent undesirable MLF.

Ethanol addition enhances acid treatment to eliminate Lactobacillus fermentum from the fermentation process for fuel ethanol production.

Science.gov (United States)

Costa, M A S; Cerri, B C; Ceccato-Antonini, S R

2018-01-01

Fermentation is one of the most critical steps of the fuel ethanol production and it is directly influenced by the fermentation system, selected yeast, and bacterial contamination, especially from the genus Lactobacillus. To control the contamination, the industry applies antibiotics and biocides; however, these substances can result in an increased cost and environmental problems. The use of the acid treatment of cells (water-diluted sulphuric acid, adjusted to pH 2·0-2·5) between the fermentation cycles is not always effective to combat the bacterial contamination. In this context, this study aimed to evaluate the effect of ethanol addition to the acid treatment to control the bacterial growth in a fed-batch system with cell recycling, using the industrial yeast strain Saccharomyces cerevisiae PE-2. When only the acid treatment was used, the population of Lactobacillus fermentum had a 3-log reduction at the end of the sixth fermentation cycle; however, when 5% of ethanol was added to the acid solution, the viability of the bacterium was completely lost even after the first round of cell treatment. The acid treatment +5% ethanol was able to kill L. fermentum cells without affecting the ethanol yield and with a low residual sugar concentration in the fermented must. In Brazilian ethanol-producing industry, water-diluted sulphuric acid is used to treat the cell mass at low pH (2·0) between the fermentative cycles. This procedure reduces the number of Lactobacillus fermentum from 10 7 to 10 4  CFU per ml. However, the addition of 5% ethanol to the acid treatment causes the complete loss of bacterial cell viability in fed-batch fermentation with six cell recycles. The ethanol yield and yeast cell viability are not affected. These data indicate the feasibility of adding ethanol to the acid solution replacing the antibiotic use, offering a low cost and a low amount of residue in the biomass. © 2017 The Society for Applied Microbiology.

Integrated sulphur management : gas, oil sands, reclamation and the challenges of fluctuating demand

International Nuclear Information System (INIS)

Pineau, R.

2009-01-01

International Commodities Export Corporation is a privately held company that provides fully integrated service offerings to add maximum value in designing, building, owning, and operating sulphur assets. The company also offers in-house, engineering, procurement and project management, as well as supply management, transportation and distribution services. It also has expertise in marine transportation. This presentation discussed integrated sulphur management, with particular focus on gas, oil sands, reclamation and the challenges of fluctuating demand. The presentation provided an overview of the sulphur market and oil sands sulphur. Key considerations for oil sands producers were also presented. The challenges of fluctuating demand include price and volume considerations; logistics; geography and distance to market; export/offshore versus domestic/United States; seasonal considerations; and an inelastic sulphur market. The presentation concluded with a status update of ICEC's initiative and the advantages of Prince Rupert, an economically viable export infrastructure to producers without onsite forming facilities. figs

Short-term effects of repeated olfactory administration of homeopathic sulphur or pulsatilla on electroencephalographic alpha power in healthy young adults.

Science.gov (United States)

Bell, Iris R; Brooks, Audrey J; Howerter, Amy; Jackson, Nicholas; Schwartz, Gary E

2011-10-01

Homeopathic pathogenetic trials usually rely on symptom self report measures. Adding objective biomarkers could enhance detection of subtle initial remedy effects. The present feasibility study examined electroencephalographic (EEG) effects of repeated olfactory administration of two polycrest remedies. College student volunteers (ages 18-30, both sexes) from an introductory psychology course were screened for good health and relatively elevated Sulphur or Pulsatilla symptom scores on the Homeopathic Constitutional Type Questionnaire (CTQ). Subjects underwent a series of 3 once-weekly double-blind sessions during which they repeatedly sniffed the remedy matched to their CTQ type and solvent controls. Each remedy was given in a 6c, 12c, and 30c potency, one potency per week, in randomly assigned order. Solvent controls included both plain distilled water and a water-ethanol (95%) solution. All sniff test solutions were further diluted just prior to laboratory sessions (0.5 ml test solution in 150 ml distilled water). Within a session, remedies and control solvents were administered via 2-s sniffs (8 sniffs of each of 4 different succussion levels for the potency in randomized order). Primary outcome variable was relative EEG power (alpha 1 8-10 Hz; alpha 2 10-12 Hz) averaged over 19 electrode sites, including all succussions for a given potency. Mixed-effect models revealed significant main effects for remedy type (Sulphur >Pulsatilla) in both alpha bands, controlling for gender, baseline resting EEG alpha, and solvent control responses. Additional analyses showed significant nonlinear interactions between dilution and time (weekly session) in alpha 2 for both remedies and alpha 1 for Sulphur. EEG alpha offers an objective biomarker of remedy effects for future studies and potential method for distinguishing time-dependent effects of specific remedies and remedy potencies from one another. Copyright © 2011 The Faculty of Homeopathy. Published by Elsevier Ltd

Automatic colorimetric determination of low concentrations of sulphate for measuring sulphur dioxide in ambient air

Energy Technology Data Exchange (ETDEWEB)

Persson, G A

1966-01-01

An automatic colorimetric method for the determination of low concentrations of sulphate (0-10 microgram/ml) using the thoron indicator is described. Total amounts of sulphate as small as 0.3 micrograms can be determined. The sulphate is precipitated with barium perchlorate and the excess of barium is indicated with 1-(o-arsenophenylazo)-2-naphthol-3-6-disulfonic acid(thoron). The procedure is worked out primarily for the determination of sulphur dioxide in air after absorption in diluted hydrogen peroxide.

Alternative leaching processes for uranium ores

International Nuclear Information System (INIS)

Ring, R.J.

1979-01-01

Laboratory studies have been carried out to compare the extraction of uranium from Australian ores by conventional leaching in sulphuric acid with that obtained using hydrochloric acid and acidified ferric sulphate solutions. Leaching with hydrochloric acid achieved higher extractions of radium-226 but the extraction of uranium was reduced considerably. The use of acidified ferric sulphate solution reduced acid consumption by 20-40% without any detrimental effect on uranium extraction. The ferric ion, which is reduced during leaching, can be reoxidized and recycled after the addition of acid makeup. Hydrogen peroxide was found to be an effective oxidant in conventional sulphuric acid leaching. It is more expensive than alternative oxidants, but it is non-polluting, lesser quantities are required and acid consumption is reduced

Feasibility of high-resolution continuum source molecular absorption spectrometry in flame and furnace for sulphur determination in petroleum products

Science.gov (United States)

Kowalewska, Zofia

2011-07-01

For the first time, high-resolution molecular absorption spectrometry with a high-intensity xenon lamp as radiation source has been applied for the determination of sulphur in crude oil and petroleum products. The samples were analysed as xylene solutions using vaporisation in acetylene-air flame or in an electrothermally heated graphite furnace. The sensitive rotational lines of the CS molecule, belonging to the ∆ν = 0 vibrational sequence within the electronic transition X 1∑ + → A 1П, were applied. For graphite furnace molecular absorption spectrometry, the Pd + Mg organic modifier was selected. Strong interactions with Pd atoms enable easier decomposition of sulphur-containing compounds, likely through the temporal formation of Pd xS y molecules. At the 258.056 nm line, with the wavelength range covering central pixel ± 5 pixels and with application of interactive background correction, the detection limit was 14 ng in graphite furnace molecular absorption spectrometry and 18 mg kg -1 in flame molecular absorption spectrometry. Meanwhile, application of 2-points background correction found a characteristic mass of 12 ng in graphite furnace molecular absorption spectrometry and a characteristic concentration of 104 mg kg -1 in flame molecular absorption spectrometry. The range of application of the proposed methods turned out to be significantly limited by the properties of the sulphur compounds of interest. In the case of volatile sulphur compounds, which can be present in light petroleum products, severe difficulties were encountered. On the contrary, heavy oils and residues from distillation as well as crude oil could be analysed using both flame and graphite furnace vaporisation. The good accuracy of the proposed methods for these samples was confirmed by their mutual consistency and the results from analysis of reference samples (certified reference materials and home reference materials with sulphur content determined by X-ray fluorescence

Feasibility of high-resolution continuum source molecular absorption spectrometry in flame and furnace for sulphur determination in petroleum products

Energy Technology Data Exchange (ETDEWEB)

Kowalewska, Zofia, E-mail: zofia.kowalewska@obr.pl

2011-07-15

For the first time, high-resolution molecular absorption spectrometry with a high-intensity xenon lamp as radiation source has been applied for the determination of sulphur in crude oil and petroleum products. The samples were analysed as xylene solutions using vaporisation in acetylene-air flame or in an electrothermally heated graphite furnace. The sensitive rotational lines of the CS molecule, belonging to the {Delta}{nu} = 0 vibrational sequence within the electronic transition X{sup 1}{Sigma}{sup +} {yields} A{sup 1}{Pi}, were applied. For graphite furnace molecular absorption spectrometry, the Pd + Mg organic modifier was selected. Strong interactions with Pd atoms enable easier decomposition of sulphur-containing compounds, likely through the temporal formation of Pd{sub x}S{sub y} molecules. At the 258.056 nm line, with the wavelength range covering central pixel {+-} 5 pixels and with application of interactive background correction, the detection limit was 14 ng in graphite furnace molecular absorption spectrometry and 18 mg kg{sup -1} in flame molecular absorption spectrometry. Meanwhile, application of 2-points background correction found a characteristic mass of 12 ng in graphite furnace molecular absorption spectrometry and a characteristic concentration of 104 mg kg{sup -1} in flame molecular absorption spectrometry. The range of application of the proposed methods turned out to be significantly limited by the properties of the sulphur compounds of interest. In the case of volatile sulphur compounds, which can be present in light petroleum products, severe difficulties were encountered. On the contrary, heavy oils and residues from distillation as well as crude oil could be analysed using both flame and graphite furnace vaporisation. The good accuracy of the proposed methods for these samples was confirmed by their mutual consistency and the results from analysis of reference samples (certified reference materials and home reference materials with

Sulphur removal from used automotive lubricating oil by ionizing radiation

International Nuclear Information System (INIS)

Scapin, Marcos Antonio; Duarte, Celina Lopes; Sato, Ivone Mulako

2007-01-01

Following the worldwide evolution with the purpose of a higher control of vehicular emissions, the specialists have looked for clean technologies and efficient procedures to make vehicular emissions free of pollutants. Much attention is given to the sulphur concentration in the gasoline, diesel and lubricating oils. The ionizing radiation is a promising technology for the removal of this pollutant when compared to other conventional treatment methods. In this work, the ionizing radiation was used to remove in significant levels the presence of sulphur in automotive motor oil. A 1000 mL sample of used automotive lubricating oil from a gas station was collected. This sample was fractioned and irradiated with 10, 20 50, 100, 200 and 500 kGy doses in a 60 Co irradiator (GAMMACELL-220 - 12 kCi). The 50 and 70% (v/v) of MilliQ water and 30% (v/v) of hydrogen peroxide was used to improve the radiolysis The sulphur element before and after the irradiation was determined by X-ray fluorescence technique (WDXRF) using the Fundamental Parameters Method. The results showed approximately 70% sulphur removal at 500 kGy irradiation dose with 70% (v/v) of MilliQ water addition. (author)

Characterization of electrochemical and passive behaviour of Alloy 59 in acid solution

International Nuclear Information System (INIS)

Luo, Hong; Gao, Shujun; Dong, Chaofang; Li, Xiaogang

2014-01-01

Highlights: • A considerably thinner n-type passive film is observed on the Alloy-59. • The passive film formed in air was thicker than that formed in acid solution. • Primary constituents of passive film in air and acid solution are (Cr, Ni)-oxides and (Cr, Ni) hydroxides, respectively. - Abstract: The electrochemical behaviour and passive film properties of the Alloy 59 in sulfuric acid solution was evaluated by the potentiodynamic electrochemical measurements, electrochemical impedance spectroscopy, Mott-Schottky approach, and ex situ surface analytical technique as X-ray photoelectron spectroscopy (XPS) and Auger Electronic Spectrometer (AES). The results confirmed that the Alloy 59 exhibits well passive behaviour. A considerably thinner n-type passive film is observed on this type alloy. Based on the evaluations of surface composition analysis, the primary constituents of passive film formed in the air and acid solution are different, with the (Cr, Ni)-oxides and (Cr, Ni) hydroxides, respectively

Chronic aspartame intake causes changes in the trans-sulphuration pathway, glutathione depletion and liver damage in mice

Directory of Open Access Journals (Sweden)

Isabela Finamor

2017-04-01

Full Text Available No-caloric sweeteners, such as aspartame, are widely used in various food and beverages to prevent the increasing rates of obesity and diabetes mellitus, acting as tools in helping control caloric intake. Aspartame is metabolized to phenylalanine, aspartic acid, and methanol. Our aim was to study the effect of chronic administration of aspartame on glutathione redox status and on the trans-sulphuration pathway in mouse liver. Mice were divided into three groups: control; treated daily with aspartame for 90 days; and treated with aspartame plus N-acetylcysteine (NAC. Chronic administration of aspartame increased plasma alanine aminotransferase (ALT and aspartate aminotransferase activities and caused liver injury as well as marked decreased hepatic levels of reduced glutathione (GSH, oxidized glutathione (GSSG, γ-glutamylcysteine ​​(γ-GC, and most metabolites of the trans-sulphuration pathway, such as cysteine, S-adenosylmethionine (SAM, and S-adenosylhomocysteine ​​(SAH. Aspartame also triggered a decrease in mRNA and protein levels of the catalytic subunit of glutamate cysteine ligase (GCLc and cystathionine γ-lyase, and in protein levels of methionine adenosyltransferase 1A and 2A. N-acetylcysteine prevented the aspartame-induced liver injury and the increase in plasma ALT activity as well as the decrease in GSH, γ-GC, cysteine, SAM and SAH levels and GCLc protein levels. In conclusion, chronic administration of aspartame caused marked hepatic GSH depletion, which should be ascribed to GCLc down-regulation and decreased cysteine levels. Aspartame triggered blockade of the trans-sulphuration pathway at two steps, cystathionine γ-lyase and methionine adenosyltransferases. NAC restored glutathione levels as well as the impairment of the trans-sulphuration pathway.

Chronic aspartame intake causes changes in the trans-sulphuration pathway, glutathione depletion and liver damage in mice.

Science.gov (United States)

Finamor, Isabela; Pérez, Salvador; Bressan, Caroline A; Brenner, Carlos E; Rius-Pérez, Sergio; Brittes, Patricia C; Cheiran, Gabriele; Rocha, Maria I; da Veiga, Marcelo; Sastre, Juan; Pavanato, Maria A

2017-04-01

No-caloric sweeteners, such as aspartame, are widely used in various food and beverages to prevent the increasing rates of obesity and diabetes mellitus, acting as tools in helping control caloric intake. Aspartame is metabolized to phenylalanine, aspartic acid, and methanol. Our aim was to study the effect of chronic administration of aspartame on glutathione redox status and on the trans-sulphuration pathway in mouse liver. Mice were divided into three groups: control; treated daily with aspartame for 90 days; and treated with aspartame plus N-acetylcysteine (NAC). Chronic administration of aspartame increased plasma alanine aminotransferase (ALT) and aspartate aminotransferase activities and caused liver injury as well as marked decreased hepatic levels of reduced glutathione (GSH), oxidized glutathione (GSSG), γ-glutamylcysteine ​​(γ-GC), and most metabolites of the trans-sulphuration pathway, such as cysteine, S-adenosylmethionine (SAM), and S-adenosylhomocysteine ​​(SAH). Aspartame also triggered a decrease in mRNA and protein levels of the catalytic subunit of glutamate cysteine ligase (GCLc) and cystathionine γ-lyase, and in protein levels of methionine adenosyltransferase 1A and 2A. N-acetylcysteine prevented the aspartame-induced liver injury and the increase in plasma ALT activity as well as the decrease in GSH, γ-GC, cysteine, SAM and SAH levels and GCLc protein levels. In conclusion, chronic administration of aspartame caused marked hepatic GSH depletion, which should be ascribed to GCLc down-regulation and decreased cysteine levels. Aspartame triggered blockade of the trans-sulphuration pathway at two steps, cystathionine γ-lyase and methionine adenosyltransferases. NAC restored glutathione levels as well as the impairment of the trans-sulphuration pathway. Copyright © 2017. Published by Elsevier B.V.

Effect of sulphur fertilisation on yield and quality of white mustard seeds

Directory of Open Access Journals (Sweden)

Pavel Ryant

2009-01-01

Full Text Available The objective of the present study was to estimate the effect of different forms of sulphur on yields and qualitative parameters of white mustard seeds. This topic was studied in 2004 in the form of a pot trial in a vegetation hall and linked up with an identical experiment with spring wheat conducted in 2003. Besides the control variant not fertilised with sulphur (1 we fertilised the soil with elemental sulphur (2, ammonium sulphate (3 and gypsum (4 and applied foliar dressing of elemental sulphur with bentonite (5. For all variants the nitrogen dose was 0.9 g per pot (0.15 g . kg−1 of soil and for va­riants 2 to 4 it was 1 g of sulphur per pot (0.17 g. kg−1 of soil. Foliar dressing of elemental sulphur (S0 was not applied until the stage of six true leaves in a dose of 10 kg per ha (0.032 g per pot.Significantly higher yields of white mustard seeds were achieved after foliar application of S0 which can be also due to its fungicide action. The variants where gypsum was applied showed the highest average number of branches and pods and also straw yields. After gypsum fertilisation or foliar application of S0 the oil content in the mustard seeds exceeded 25%; this is the minimal content required for the production of good quality mustard. The 1000-seed weight was significantly higher after foliar application of S0. The proportion of seeds greyish on the surface, a sign of mildew, significantly decreased after fertilisation with all forms of sulphur, but most of all after foliar application of S0.Fertilisation with ammonium sulphate reduced the exchangeable soil reaction after harvest. On the other hand gypsum alkalised the soil environment and increased the content of available calcium and water-soluble sulphur. The soil of the variant where foliar dressing of S0 was applied had a higher content of available calcium after harvest. The least amount of available sulphur and phosphorus in the soil was seen after foliar

Acid ran and below-cloud scavenging in south-western China

International Nuclear Information System (INIS)

Tanner, P.A.; Lei, H.C.; Huang, M.Y.; Shen, Z.L.

1997-01-01

Major urban areas in south-western China exhibit unique air pollution problems due to increasing use of high sulphur-content fuels in an environment of unfavourable topography and climate. Ambient levels of sulphur dioxide exceed the air quality objectives, and this gas is the major precursor of acid rain. Cloudwater chemistry studies are reported for urban, suburban and countryside locations, during the period 1985-89. Although cloudwater acidity was found to increase towards the cloud base, the acidity was much greater for rainwater samples collected simultaneously, and was more pronounced in urban rather than neighbouring suburban or countryside regions. The main contribution to the acidity arises from below-cloud scavenging of gas and aerosol and model calculations are able to simulate this behaviour

Chemical dosimetry by UV spectrophotometry of aqueous ascorbic acid solutions

International Nuclear Information System (INIS)

Alian, A.; El-Assay, N.B.; Abdel-Rehim, F.; Amin, N.E.; McLaughlin, W.L.; Roushdy, H.

1984-01-01

The decrease in the ultraviolet absorption of aqueous solutions of ascorbic acid brought about by large doses of gamma radiation has been investigated as a means of developing a new chemical dosimeter. Because of spontaneous ring opening under various conditions after dissolution in water, some additives were examined as possible stabilizers against such denaturing of aqueous ascorbic acid. At an ascorbic acid concentration of 10 -4 M, either 1 to 2% glycine or 0.2 M NaCl was found to be a good stabilizer. A mechanism of radiation chemistry has been proposed based on hydroxyl radical and hydroxyl adduct intermediates, leading to dehydroascorbic acid through the ascorbate complex. The optimum dosimeter solution covers an absorbed dose range approx. 50 to 350 Gy, when measured at 264 nm wavelength. The G-values for dehydroascorbic acid production were determined to be 2.94 +- 0.33 and 2.43 +- 0.11 (100 eV) -1 , with glycine and NaCl used respectively as stabilizers. (author)

Characterization of acid tar waste from benzol purification | Danha ...

African Journals Online (AJOL)

The use of concentrated sulphuric acid to purify benzene, toluene and xylene produces acidic waste known as acid tar. The characterization of the acid tar to determine the composition and physical properties to device a way to use the waste was done. There were three acid tars two from benzene (B acid tar), toluene and ...

Investigation of the possibility of binding fly ash particles by elemental sulphur

Directory of Open Access Journals (Sweden)

Vidojković V.

2006-01-01

Full Text Available Thermal power plants in Serbia use lignite for electrical power production The secondary product of coal combustion is fly ash in the amount of 17%. Fly ash causes the pollution of air, water and soil, and also cause many human, especially lung diseases. Secondary sulphur is a product of crude oil refining. The aim of this study was to investigate the use of sulphur as a bonding material in ultra fine particle agglomeration (smaller than 63 μm in fly ash. The agglomeration should make the ash particles larger and heavy enough to fall without flying fractions. The experiments showed that during the homogenization of the ashes and sulphur from 150 to 170 °C in a reactor with intensive mixing, an amount of 15% sulphur was sufficient to bond particles and cause agglomeration without visible flying fractions.

Whence the acid raindrop

International Nuclear Information System (INIS)

Heaton, T.H.E.

1987-01-01

Absorption of NO 2 can cause damage in animals and plants and, if present trends for NO x emissions continue, their by-product nitric acid may soon overtake sulphuric acid as the main acidifying agent of 'acid' rain. In response to this problem the feasibility of reducing NO x emissions from power stations is being studied. Although there can be no doubt that these expensive controls are desirable, their benefits are difficult to predict for two reasons: NO x is not only emitted by fuel combustion and the degree to which an industrialised country benefits from the implementation of NO x emission controls depends on how much its pollutant 'fall out' is immediately returned from the atmosphere, and how much is exported to neighbouring countries. The above factors involve questions regarding the source and reaction mechanisms for nitrogen compounds in the atmosphere. Because stable isotope ratio analysis has proved to be of value in providing answers to such questions in other environments, an investigation of the 15 N/ 14 N ratios of atmospheric gases (NO x , NH 3 ) and their solution products in rain (NO 3 , NH + 4 ) seemed to be justified

Ultrasound-assisted extraction for total sulphur measurement in mine tailings

Energy Technology Data Exchange (ETDEWEB)

Khan, Adnan Hossain, E-mail: ad_li2@yahoo.com [Department of Civil and Environmental Engineering, University of Western Ontario (Canada); Shang, Julie Q.; Alam, Raquibul [Department of Civil and Environmental Engineering, University of Western Ontario (Canada)

2012-10-15

Highlights: Black-Right-Pointing-Pointer We develop a total sulphur measuring procedure of mine tailings. Black-Right-Pointing-Pointer Ultrasound is used in the sample pre-treatment process. Black-Right-Pointing-Pointer Full factorial design is applied to identify the best level of effecting factors. - Abstract: A sample preparation method for percentage recovery of total sulphur (%S) in reactive mine tailings based on ultrasound-assisted digestion (USAD) and inductively coupled plasma-optical emission spectroscopy (ICP-OES) was developed. The influence of various methodological factors was screened by employing a two-level and three-factor (2{sup 3}) full factorial design and using KZK-1, a sericite schist certified reference material (CRM), to find the optimal combination of studied factors and %S. Factors such as the sonication time, temperature and acid combination were studied, with the best result identified as 20 min of sonication, 80 Degree-Sign C temperature and 1 ml of HNO{sub 3}:1 ml of HCl, which can achieve 100% recovery for the selected CRM. Subsequently a fraction of the 2{sup 3} full factorial design was applied to mine tailings. The percentage relative standard deviation (%RSD) for the ultrasound method is less than 3.0% for CRM and less than 6% for the mine tailings. The investigated method was verified by X-ray diffraction analysis. The USAD method compared favorably with existing methods such as hot plate assisted digestion method, X-ray fluorescence and LECO Trade-Mark-Sign -CNS method.

Transport of metals and sulphur in magmas by flotation of sulphide melt on vapour bubbles

Science.gov (United States)

Mungall, J. E.; Brenan, J. M.; Godel, B.; Barnes, S. J.; Gaillard, F.

2015-03-01

Emissions of sulphur and metals from magmas in Earth’s shallow crust can have global impacts on human society. Sulphur-bearing gases emitted into the atmosphere during volcanic eruptions affect climate, and metals and sulphur can accumulate in the crust above a magma reservoir to form giant copper and gold ore deposits, as well as massive sulphur anomalies. The volumes of sulphur and metals that accumulate in the crust over time exceed the amounts that could have been derived from an isolated magma reservoir. They are instead thought to come from injections of multiple new batches of vapour- and sulphide-saturated magmas into the existing reservoirs. However, the mechanism for the selective upward transfer of sulphur and metals is poorly understood because their main carrier phase, sulphide melt, is dense and is assumed to settle to the bottoms of magma reservoirs. Here we use laboratory experiments as well as gas-speciation and mass-balance models to show that droplets of sulphide melt can attach to vapour bubbles to form compound drops that float. We demonstrate the feasibility of this mechanism for the upward mobility of sulphide liquids to the shallow crust. Our work provides a mechanism for the atmospheric release of large amounts of sulphur, and contradicts the widely held assumption that dense sulphide liquids rich in sulphur, copper and gold will remain sequestered in the deep crust.

the amino acid composition of selected south african feed ingredients

African Journals Online (AJOL)

of assessing the balance of amino acids, each is presented as a percentage of the requirements of broilers up to 3 weeks of age. ... nutritional importance of the total sulphur amino acids .... out and the primary amino acid analysis result sheet.

Hydrophobic interactions between polymethacrylic acid and sodium laureth sulfate in aqueous solutions

Science.gov (United States)

Yaremko, Z. M.; Fedushinskaya, L. B.; Burka, O. A.; Soltys, M. N.

2014-09-01

The role of hydrophobic interaction in the development of associative processes is demonstrated, based on the concentration dependences of the viscosity and pH of binary solutions of polymethacrylic acid as an anionic polyelectrolyte and sodium laureth sulfate as an anionic surfactant. It is found that the inflection point on the dependence of the difference between the pH values of binary solutions of polymethacrylic acid and sodium laureth sulfate on the polyelectrolyte concentration is a criterion for determining the predominant contribution from hydrophobic interaction, as is the inflection point on the dependence of pH of individual solutions of polymethacrylic acid on the polyelectrolyte concentration.

Studies of Tc oxidation states in humic acid solutions

International Nuclear Information System (INIS)

Wang Bo; Liu Dejun; Yao Jun

2011-01-01

The oxidation state of Tc is an important aspect of the speciation in groundwater which contained organic substances due to it control the precipitation, complexation, sorption and colloid formation behavior of the Tc under HWL geological disposal conditions. In present work, the oxidation states of Tc were investigated using the LaCl 3 coagulation method and solution extraction method in aqueous solutions in which the humic acid concentration range is from 0 to 20 mg/L and the Tc (VII) concentration is about 10 -8 mol/L. The radiocounting of 99 Tc was determined using liquid scintillation spectrometry. The humic acid will influence the radiocounting ratio of 99 Tc apparently, however, the quenching effect can be restrained once keep the volume of the cocktail to about twenty times of the sample volume. The LaCl 3 coagulation method was carried out for the investigation of Tc oxidation states in humic acid aqueous systems at about pH 8. The tetraphenylarsonium chloride (TPA)-chloroform extraction method was used also simultaneously to investigation the concentrations of Tc (IV) and Tc (VII) for the availability of the LaCl 3 precipitation method, and the experimental results demonstrate that tetravalent technetium and pertechnetate concentration are well agreement with the LaCl 3 precipitation method. These two experimental results demonstrated that Tc (VII) is very stable in the Tc (VII)-humic acid system during a 350 days experimental period, and the Tc (IV) concentrations are very lower, that is indicate that there didn't oxidizing reactions between the Fluka humic acid and Tc (VII) in aqueous solutions under anaerobic conditions. That means the presence of humic acids even in anaerobic groundwater is disadvantage for the retardance of radionuclides. (authors)

EPR spectra of vanadyl(2) intra-complexes with amino acids in solutions

International Nuclear Information System (INIS)

Shodiev, U.M.; Musaev, Z.M.; Khodzhaev, O.F.; Usmankhodzhaeva, Ya.S.; Parpiev, N.A.

1987-01-01

EPR spectra of vanadyl (2) intracomplexes with glycine, α- and β-alanines, benzoylglycine, lencine, glutamine and the aspartic acid of VOL 2 xH 2 O composition as well as with cystine of VOLxH 2 O composition (where L-monodeprotonated, in case of cystine and the aspartic acid - dideprotonated form of the amino acid) in aqueous, methanol, dimethylsulfoxide and pyridine solutions are studied. It is established that the structure determined in the solid state is retained in the dimethylsulfoxide solution and partially - in methanol. In aqueous, pyridine and partially in methanol solutions complexes are distorted and two molecules of the amino acid are coordinated monodentately through oxygen atoms of the carboxyl group, and ''vacant'' coordination places in the equatorial plane take two molecules of the solvent. From the data obtained it follows that the metal - nitrogen bond in the vanadyl (2) complexes studied with amino acids is not so strong than the metal - oxygen bond of the carboxyl ligand group

Effect of feedstock end boiling point on product sulphur during ultra deep diesel hydrodesulphurization

Energy Technology Data Exchange (ETDEWEB)

Stratiev, D.; Ivanov, A.; Jelyaskova, M. [Lukoil Neftochim Bourgas AD, Bourgas (Bulgaria)

2004-12-01

An investigation was carried out to test the feasibility of producing 50 and 10 ppm sulphur diesel in a conventional hydrotreating unit operating at low pressure conditions by varying the feedstock end boiling point. Middle distillate fractions distilled from a mixture of Ural crude oil, reduced crude, vacuum gas oil, naphtha and low sulphur crude oils with 95% vol. points of 274, 359, 343, 333, and 322 C (ASTM D-86 method) and sulphur contents of 0.36, 0.63, 0.99, 0.57, and 0.47%, respectively, were hydrotreated using the Akzo Nobel Stars family Co-Mo KF-757 catalyst in a trickle bed pilot plant at following conditions: reactor inlet temperature range of 320-360 C; liquid hourly space velocity (LHSV) range of 1-2 h{sup -1}; total reactor pressure of 3.5 MPa; treating gas: feedstock ratio of 250 Nm{sup 3}/m{sup 3}. It was found that the determinant factor for the attainment of ultra low sulphur levels during middle distillate hydrodesulphurization was not the total sulphur content in the feed but the content of the material boiling above 340 C (according to TBP). For all LHSVs and reactor inlet temperatures studied the product sulphur dependence on the feed 340 C+ fraction content was approximated by second order power law. The specification of 50 ppm sulphur was achieved with all studied feedstocks. However the 10ppm sulphur limit could be met only by feedstocks with 95% vol. points below 333 C, which is accompanied by about 10% reduction of the diesel potential. The hydrotreatment tests on a blend 80% straight run gas oil (ASTM D-86 95% vol. of 274 C)/20%FCC LCO (ASTM D-86 95% vol. of 284 C) showed product sulphur levels which were not higher than those obtained by hydrotreatment of the straight run gas oil, indicating that undercutting the FCC LCO gives the refiner the opportunity to increase the potential for the production of 10 ppm sulphur diesel at the conditions of the conventional hydrotreating unit operating at low pressure. The product cetane index was

Reprint of “Experiences in sulphur capture in a 30 MWth Circulating Fluidized Bed boiler under oxy-combustion conditions”

International Nuclear Information System (INIS)

Gómez, M.; Fernández, A.; Llavona, I.; Kuivalainen, R.

2015-01-01

CO 2 and SO 2 from fossil fuel combustion are contributors to greenhouse effect and acid rain respectively. Oxy-combustion technology produces a highly concentrated CO 2 stream almost ready for capture. Circulating Fluidized Bed (CFB) boiler technology allows in-situ injection of calcium-based sorbents for efficient SO 2 capture. CIUDEN's 30 MWth CFB boiler, supplied by Foster Wheeler and located at the Technology Development Centre for CO 2 Capture and Transport (es.CO 2 ) in Spain, is the first of its kind for executing test runs at large pilot scale under both air-combustion and oxy-combustion conditions. In this work, SO 2 emissions under different scenarios have been evaluated. Variables such as limestone composition, Ca/S molar ratio and bed temperature among others have been considered along different test runs in both air-combustion and oxy-combustion conditions to analyse its influence on SO 2 abatement. Fly and bottom ash, together with flue gas analysis have been carried-out. Desulphurization performance tests results are presented. - Highlights: • Sulphur capture efficiency (%) was higher in oxy-combustion compared to air-combustion in a 30 MW thermal CFB boiler using anthracite and limestone as sulphur sorbent. • For a Ca/S molar ratio higher than 2.6 there was barely any improvement on sulphur capture efficiency for both air-combustion and oxy-combustion conditions in a 30 MW thermal CFB boiler using anthracite and limestone as sulphur sorbent. • Optimum temperature for sulphur capture at a fixed Ca/S molar ratio is around 880–890 °C under oxy-combustion conditions and for anthracite coal with limestone as sorbent in a 30 MW thermal CFB boiler

Enthalpic characteristics of interactions occurring between an ascorbic acid and some saccharides in aqueous solutions

International Nuclear Information System (INIS)

Terekhova, Irina V.; Kulikov, Oleg V.; Titova, Elena S.

2004-01-01

The enthalpies of solution of mono- and disaccharides were measured in water and aqueous ascorbic acid solutions at 298.15 K using a calorimeter of solution. Enthalpies of transfer of saccharides from water to aqueous ascorbic acid solutions were derived, and enthalpic coefficients of pair interaction h xy were calculated according to MacMillan-Mayer theory. Interactions of ascorbic acid with D-fructose and sucrose are energetically favorable and characterized by negative h xy coefficients while h xy for the interactions occurring between ascorbic acid and α-D glucose, D-galactose and maltose are positive. The obtained results are interpreted in terms of the influence of structure and solvation of solutes on the thermodynamic parameters of their interaction in solutions

Precipitation of plutonium from acidic solutions using magnesium oxide

International Nuclear Information System (INIS)

Jones, S.A.

1994-01-01

Magnesium oxide will be used as a neutralizing agent for acidic plutonium-containing solutions. It is expected that as the magnesium oxide dissolves, the pH of the solution will rise, and plutonium will precipitate. The resulting solid will be tested for suitability to storage. The liquid is expected to contain plutonium levels that meet disposal limit requirements

Savannah River Site Tank Cleaning: Corrosion Rate For One Versus Eight Percent Oxalic Acid Solution

International Nuclear Information System (INIS)

Ketusky, E.; Subramanian, K.

2011-01-01

Until recently, the use of oxalic acid for chemically cleaning the Savannah River Site (SRS) radioactive waste tanks focused on using concentrated 4 and 8-wt% solutions. Recent testing and research on applicable dissolution mechanisms have concluded that under appropriate conditions, dilute solutions of oxalic acid (i.e., 1-wt%) may be more effective. Based on the need to maximize cleaning effectiveness, coupled with the need to minimize downstream impacts, SRS is now developing plans for using a 1-wt% oxalic acid solution. A technology gap associated with using a 1-wt% oxalic acid solution was a dearth of suitable corrosion data. Assuming oxalic acid's passivation of carbon steel was proportional to the free oxalate concentration, the general corrosion rate (CR) from a 1-wt% solution may not be bound by those from 8-wt%. Therefore, after developing the test strategy and plan, the corrosion testing was performed. Starting with the envisioned process specific baseline solvent, a 1-wt% oxalic acid solution, with sludge (limited to Purex type sludge-simulant for this initial effort) at 75 C and agitated, the corrosion rate (CR) was determined from the measured weight loss of the exposed coupon. Environmental variations tested were: (a) Inclusion of sludge in the test vessel or assuming a pure oxalic acid solution; (b) acid solution temperature maintained at 75 or 45 C; and (c) agitation of the acid solution or stagnant. Application of select electrochemical testing (EC) explored the impact of each variation on the passivation mechanisms and confirmed the CR. The 1-wt% results were then compared to those from the 8-wt%. The immersion coupons showed that the maximum time averaged CR for a 1-wt% solution with sludge was less than 25-mils/yr for all conditions. For an agitated 8-wt% solution with sludge, the maximum time averaged CR was about 30-mils/yr at 50 C, and 86-mils/yr at 75 C. Both the 1-wt% and the 8-wt% testing demonstrated that if the sludge was removed from