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Activated carbons treated with sulphuric acid: catalysts for catalytic wet peroxide oxidation

Gomes, Helder; Miranda, Sandra; Sampaio, Maria; Silva, Adrián; Faria, Joaquim
Fonte: EAAOP Publicador: EAAOP
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
386.8815%
The commercial activated carbon Norit ROX 0.8 was subjected to different liquid phase treatments in order to produce activated carbons with varying surface chemistry and acid/base character. The prepared materials were used as catalysts in the catalytic wet peroxide oxidation of the acid dye Chromotrope 2R in order to assess their removal activity. Chemical characterization of the prepared materials includes determination of the point of zero charge and evaluation of the concentration and nature of acidic and basic surface functionalities by acid/base titrations and temperature programmed desorption. The relationship between the surface chemistry and efficiency for dye removal is discussed. In general, dye removal is increased when using catalysts with higher basic character, due to enhanced electrostatic attraction between the acid dye and the catalyst surface when compared with catalysts presenting acidic character. In addition, treatment with sulphuric acid introduces on the catalysts surface sulphur containing groups, which promotes the surface interaction between the pollutant and hydrogen peroxide. This leads to improved dye removal resulting from higher production of hydroxyl radicals close to the pollutant. Reutilization studies show that the catalyst prepared by sulphuric acid treatment is able to keep its performance in successive runs.

Catalytic properties of carbon xerogels for wet oxidation of aniline

Machado, Bruno; Ribeiro, Andreia; Moreira, Ivo; Rosário, Márcio; Gomes, Helder; Figueiredo, José; Faria, Joaquim
Fonte: EAAOP Publicador: EAAOP
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
382.0508%
The main objective of this work was to develop carbon materials suitable to be used efficiently in catalytic wet air oxidation (CWAO) processes. Accordingly, carbon xerogels with different mesoporous surface area and chemistry were prepared by the conventional sol-gel approach and tested in the CWAO of aniline at 200ºC and 6.9 bar of oxygen partial pressure. The developed materials showed high activity in aniline and total organic carbon removal, a clear increase in the removal efficiency relatively to non-CWAO being observed. At 200ºC, almost complete aniline conversions were obtained after one hour oxidation with high selectivity to non-organic compounds. The materials were characterized by thermogravimetric analysis, N2 adsorption and scanning electron microscopy, in order to relate their efficiency to the chemical and textural characteristics. It was concluded that the removal efficiency increases with the mesoporous character of the materials and with the concentration of oxygen containing functional groups at their surface. The results obtained indicate that mesoporous carbon xerogels are promising catalysts for CWAO processes.

Activated carbons treated with sulphuric acid: catalysts for catalytic wet peroxide oxidation

Gomes, Helder; Miranda, Sandra; Sampaio, Maria; Silva, Adrián; Faria, Joaquim
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
386.8815%
Different liquid phase thermal treatments were applied to a commercial activated carbon (Norit ROX 0.8) in order to produce modified activated carbons with varying surface chemistry and increased acidic character. Chemical characterization of the prepared materials includes determination of the point of zero charge and evaluation of the concentration and nature of acidic and basic surface functionalities by acid/base titrations and temperature programmed desorption. The prepared materials were used as catalysts in the catalytic wet peroxide oxidation of the acid dye Chromotrope 2R in order to assess their removal efficiency. The relationship between the surface chemistry and efficiency for dye removal is discussed. As expected, decreasing acidity of the catalysts surface will correlate with increasing dye conversion. Unexpectedly, treatment with sulphuric acid leads to a very high yield of dye removal which falls out of the previous correlation. This was explained in terms of the introduction of sulphur containing groups on the carbon surface, which promotes the surface interaction between the pollutant and hydrogen peroxide: higher production of hydroxyl radicals close to the pollutant leads to improved dye removal. In addition...

Wet deposition of major ions in a rural area impacted by biomass burning emissions

COELHO, Cidelmara H.; ALLEN, Andrew G.; FORNARO, Adalgiza; ORLANDO, Eduardo A.; GRIGOLETTO, Tahuana L. B.; CAMPOS, M. Lucia A. M.
Fonte: PERGAMON-ELSEVIER SCIENCE LTD Publicador: PERGAMON-ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
383.82473%
This work concerns the influence of industrialized agriculture in the tropics on precipitation chemistry. A total of 264 rain events were sampled using a wet-only collector in central Sao Paulo State, Brazil, between January 2003 and July 2007. Electroneutrality balance calculations (considering H(+), K(+), Na(+), NH(4)(+), Ca(2)(+), Mg(2)(+), Cl(-), NO(3)(-), SO(4)(2-), F(-), PO(4)(3-), H(3)CCOO(-), HCOO(-), C(2)O(4)(2-) and HCO(3)(-)) showed that there was an excess of cations (similar to 15%), which was attributed to the presence of unmeasured organic anion species originating from biomass burning and biogenic emissions. On average, the three ions NH(4)(+), NO(3)(-) and H(+) were responsible for >55% of the total ion concentrations in the rainwater samples. Concentrations (except of H(+)) were significantly higher (t-test; P = 0.05), by between two to six-fold depending on species, during the winter sugar cane harvest period, due to the practice of pre-harvest burning of the crop. Principal component analysis showed that three components could explain 88% of the variance for measurements made throughout the year: PC1 (52%, biomass burning and soil dust resuspension); PC2 (26%, secondary aerosols); PC3 (10%, road transport emissions). Differences between harvest and non-harvest periods appeared to be mainly due to an increased relative importance of road transport/industrial emissions during the summer (non-harvest) period. The volume-weighted mean (VWM) concentrations of ammonium (23.4 mu mol L(-1)) and nitrate (17.5 mu mol L(-1)) in rainwater samples collected during the harvest period were similar to those found in rainwater from Sao Paulo city...

Precipitation chemistry and wet deposition in Kruger National Park, South Africa

Mphepya, J. N.; Galy-Lacaux, C.; Lacaux, J. P.; Held, G.; Pienaar, J. J.
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica Formato: 169-183
ENG
Relevância na Pesquisa
390.59195%
The chemical composition, as well as the sources contributing to rainwater chemistry have been determined at Skukuza, in the Kruger National Park, South Africa. Major inorganic and organic ions were determined in 93 rainwater samples collected using an automated wet-only sampler from July 1999 to June 2002. The results indicate that the rain is acidic and the averaged precipitation pH was 4.72. This acidity results from a mixture of mineral acids (82%, of which 50% is H2SO4) and organic acids (18%). Most of the H2SO4 component can be attributed to the emissions of sulphur dioxide from the industrial region on the Highveld. The wet deposition of S and N is 5.9 kgS.ha(-1).yr(-1) and 2.8 kgN.ha(-1).yr(-1), respectively. The N deposition was mainly in the form of NH4+. Terrigenous, sea salt component, nitrogenous and anthropogenic pollutants have been identified as potential sources of chemical components in rainwater. The results are compared to observations from other African regions.

Scanning electrochemical microscopy studies of micropatterned copper sulfide (CuxS) thin films fabricated by a wet chemistry method

Chen, Miao; Zhao, Jing; Zhao, Xiaocui
Fonte: Pergamon Press Publicador: Pergamon Press
Tipo: Artigo de Revista Científica
Publicado em 30/05/2011 EN
Relevância na Pesquisa
476.0213%
► Copper sulfide (CuxS) microstructures on Si wafer has been prepared using a wet chemistry method. ► To obtain high quality CuxS films, preparative conditions were optimized. Scanning electrochemical microscopy (SECM) was employed to examine the properties of the CuxS films. ► The apparent electron-transfer rate constant (k) of CuxS surface was estimated as 0.04 cm/s. ► The SECM current map showed high edge acuity of the micro-patterned CuxS.

Wet-chemistry processing of powdery raw material for high-tech ceramics

Trusova, Elena A; Vokhmintcev, Kirill V; Zagainov, Igor V
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
Publicado em 05/01/2012 EN
Relevância na Pesquisa
480.852%
The purpose of this study was to develop wet-chemistry approaches for the synthesis of ultradispersed and mesoporous metal oxide powders and powdery composites intended for usage in the production of ceramic materials with desired properties. The focus is on the development of template synthesis of mesoporous metal silicates as well as obtaining nano- and subnanopowders by a modified sol-gel technique and template methods. Families of mesoporous (2 to 300 nm) metal silicates and nano-oxides and subnanopowders (4 to 300 nm) were synthesized by the template method and modified sol-gel technique, respectively. Texture and morphology of the obtained objects have been studied by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller analysis, and N2 adsorption-desorption. It was found that morphological parameters of the metal oxide obtained by the modified sol-gel technique depend nonlinearly on the initial molar ratio value of the sol stabilizer and metal in the reaction medium as well as the nature of the stabilizer. It has been shown that the nature of structure-directing components determines the morphology of the silicate obtained by the template method: dispersion and shape of its particles. The developed laboratory technology corresponds to the conception of soft chemistry and may be adapted to the manufacture of ultradispersed materials for catalysis...

An experimental study of OH uptake by surfaces of tropospheric importance under dry and wet conditions

Park, Jong-Ho, 1973-
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 170 leaves
ENG
Relevância na Pesquisa
480.852%
The effect of relative humidity (RH) on OH uptake by surfaces of tropospheric importance was investigated. Due to diffusion limitation conditions, experiments were performed with parallel reactors packed with beads and using a surface dilution technique. A virtual cylindrical reactor approximation was developed to further quantify and confirm the reaction probability of OH for the surfaces of interest. While OH exposure of hydrophobic organic surfaces (paraffin wax, pyrene, and methane soot) did not result in measurable change in their relative hydrophilic properties, the presence of water vapor enhanced the OH reactivity on a hydrophilic organic surface (glutaric acid). The RH effect on OH uptake by sea salt and its components was dependent on the nature of the cations. Redistribution of surface ions under humid environments caused changes in pH on the inorganic surfaces, thereby influencing the rate-determining step in the reaction mechanism of heterogeneous OH uptake. This segregation effect explains why the RH effect on OH uptake by sea salt is determined by MgCl2 rather than NaC1. Experimental evidence suggests that adsorbed water on the surfaces of SiO2 and A1203 is responsible for enhancement in OH reactivity with mineral dust surfaces under high humidity conditions. Mass spectra of the gas-phase species produced from the heterogeneous reaction of OH with NaCl were obtained in order to characterize the reaction products and the kinetic mechanism. Evidence for gas-phase HC1...

Wet-chemistry Method for the Separation of No-carrier-added 211At/211gPo from 209Bi Target Irradiated by Alpha-beam in Cyclotron

ZONA C; BONARDI M L; GROPPI F; MORZENTI S.; CANELLA L; PERSICO E; MENAPACE E; ALFASSI Z.b.; ABBAS KAMEL; HOLZWARTH UWE; GIBSON PETER
Fonte: SPRINGER Publicador: SPRINGER
Tipo: Articles in Journals Formato: Printed
ENG
Relevância na Pesquisa
476.0213%
We present a fast and effective wet-chemistry method, used to obtain the pure alpha-emitter 211At/211gPo (T1/2 = 7.214 h/516 ms), produced by 209Bi(a,2n) reaction in NCA form. It is a selective radiochemical separation of the At radionuclides from the target and the impurities, characterized by a radionuclidic purity close to 100%, based on the dissolution and the dilution of the irradiated target in acidic medium, on the extraction with DIPE, followed by the back-extraction with NaOH. As a result, we obtain a yield greater than 90-97% in a range from 0.75M to 2.00M.; JRC.I.4-Nanotechnology and Molecular Imaging

Chemistry of novel nanoscale carbon materials: Nanodiamond and carbon nano-onions

Liu, Yu
Fonte: Universidade Rice Publicador: Universidade Rice
ENG
Relevância na Pesquisa
472.3139%
Nanoscience is the area of science concerning materials on the level of nanometer scale. Currently much of the discussion of nanoscience is focused on carbon-based nanostructures. Tremendous studies have been carried out on fullerenes and carbon nanotubes in the past a couple of decade due to their unique chemical and physical properties. This thesis studies the chemistry of the other two novel nanostructures in the carbon family: nanodiamond and carbon nano-onions. Nanodiamond is relatively a new engineering material with particular applications for fabrication of wear-resistant surface coatings, lubricating films and prototypes field emission displays. These materials are also of interest for studies of chemical reactivity stemming from their nanoscale particle sizes. The surface fluorination of nanodiamond at various temperatures yields a fluoro-nanodiamond with up to 8.6 at. % fluorine content. The fluoro-nanodiamond was used as a precursor for preparation of the series of functionalized nanodiamonds by subsequent reactions with alkyllithium reagents, diamines, and amino acids. The fluoro-nanodiamond and all derivatives were characterized by SEM, TEM, XRD, TG-MS, FTIR, XPS, and Raman measurements. In comparison with the pristine nanodiamond...

Fluorinated nanodiamond as a precursor for solid substrate surface coating using wet chemistry

Khabashesku, Valery N.; Liu, Yu; Halas, Nancy J.
Fonte: Universidade Rice Publicador: Universidade Rice
ENG
Relevância na Pesquisa
476.0213%
The present invention is directed to nanodiamond (ND) surface coatings and methods of making same. Such coatings are formed by a covalent linkage of ND crystals to a particular surface via linker species. The methods described herein overcome many of the limitations of the prior art in that they can be performed with standard wet chemistry (i.e., solution-based) methods, thereby permitting low temperature processing. Additionally, such coatings can potentially be applied on a large scale and for coating large areas of a variety of different substrates.

Fluorinated nanodiamond as a precursor for solid substrate surface coating using wet chemistry

Khabashesku, Valery N.; Liu, Yu; Halas, Nancy J.
Fonte: Universidade Rice Publicador: Universidade Rice
ENG
Relevância na Pesquisa
476.0213%
The present invention is directed to nanodiamond (ND) surface coatings and methods of making same. Such coatings are formed by a covalent linkage of ND crystals to a particular surface via linker species. The methods described herein overcome many of the limitations of the prior art in that they can be performed with standard wet chemistry (i.e., solution-based) methods, thereby permitting low temperature processing. Additionally, such coatings can potentially be applied on a large scale and for coating large areas of a variety of different substrates.

Layered LiNi0.5Co0.5O2 cathode materials grown by soft-chemistry via various solution methods

Julien, C.; Letranchant, C.; Rangan, S.; Lemal, M.; Ziolkiewicz, S.; Castro García, Socorro; El-Farh, L.; Benkaddour, M.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
580.852%
The lithiated nickel–cobalt oxide LiNi0.5Co0.5O2 used as cathode material was grown at low-temperature using different aqueous solution methods. The wet chemistry involved the mixture of metal salts (acetates or nitrates) with various carboxylic acid-based aqueous solutions. Physicochemical and electrochemical properties of LiNi0.5Co0.5O2 products calcined at 400–600°C were extensively investigated. The four methods used involved complexing agents such as either citric, oxalic, aminoacetic (glycine), or succinic acid in aqueous medium which functioned as a fuel, decomposed the metal complexes at low temperature, and yielded the free impurity LiNi0.5Co0.5O2 compounds. Thermal (TG–DTA) analyses and XRD data show that powders grown with a layered structure ( space group) have been obtained at temperatures below 400°C by the acidification reaction of the aqueous solutions. The local structure of synthesized products was characterized by Fourier transform infrared (FTIR) spectroscopy. The electrochemical properties of the synthesized products were evaluated in rechargeable Li cells using a non-aqueous organic electrolyte (1 M LiClO4 in propylene carbonate, PC). The LiNi0.5Co0.5O2 positive electrodes fired at 600°C exhibited good cycling behavior.

Magnetic and electronic properties of lithium cobalt oxide substituted by nickel

Gendron, F.; Castro García, Socorro; Popova, E.; Ziolkiewicz, S.; Soulette, F.; Julien, C.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
476.0213%
We measured susceptibility, electron-spin resonance, magnetization and electrical conductivity of LiCo1−yNiyO2 powders synthesized by wet-chemistry method using succinic acid as chelating agent. We found unusual properties in the nickel-rich LiCo0.2Ni0.8O2, which shows several resonance lines as a function of the temperature in the range 3.5–300 K. The signal at low magnetic field is attributed to the magnetic domains in the nanostructured sample. The two other lines correspond to the typical ferromagnetic signal observed in powdered compounds. In the temperature range 120–300 K, the unique ESR line centered at 315 mT is the paramagnetic signal with a gyromagnetic factor g=2.12, which is in good agreement with the presence of a high concentration of Ni3+ (3d7) ions. In the nickel-rich oxide, LiNi0.8Co0.2O2, the magnetic data are qualitatively well-described by the model proposed by Drillon and Panissod for a 3D ferromagnetic order.

Lithiated cobaltates for lithium-ion batteries: Structure, morphology and electrochemistry of oxides grown by solid-state reaction, wet chemistry and film deposition

Julien, C.; Castro García, Socorro
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
476.0213%
We present the structural (XRD and Raman) and electrochemical properties of various oxides of the cobaltate family (with the α-NaFeO2-type structure) grown by solid-state reaction, wet chemistry and film deposition techniques. It is shown that synthesis greatly affects the electrochemistry and cycle life characteristics of these layer structured cathode materials. HT-LiCoO2, LT-LiCoO2, doped LiCo1−yAlyO2 and LiCoO2 films are investigated.

Graphene chemistry: Synthesis and modulation

Sun, Zhengzong
Fonte: Universidade Rice Publicador: Universidade Rice
Tipo: Thesis; Text Formato: 232 p.; application/pdf
ENG
Relevância na Pesquisa
489.94508%
This thesis investigates the chemistry of graphene from its basic synthesis to further modulation of its structure, geometry and surface chemical functional groups. A series of wet chemistry and dry chemistry experiments were performed. The wet chemistry includes the diazonium salt functionalization, graphene oxidation and reduction, nanotube unzipping chemistry, graphite intercalation and exfoliation. The dry chemistry includes chemical vapor deposition and solid carbon source synthesis of graphene, the control of domain size and stacking order, graphene hydrogenation and lithographically patterned graphene superlattices. With all these chemical approaches, graphene's electrical and optical properties, solubility in organic solvents, crystallography, and chemical reactivity were carefully investigated and discussed. In addition to the fundamental chemistry of graphene, the bio- and environmental impact of this new material was also taken into consideration and investigated.

Investigating the relevance of the graduate attributes to Australian tertiary chemistry education: a staff, student and industry perspective

Ibo, Rami
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Thesis (Honours) Formato: 95 pages
Relevância na Pesquisa
478.43426%
Universities are increasingly seen to have both a research and a vocational training role. They have responded to this expectation by proclaiming the graduate attributes on their public websites. However, disciplines are also expected to develop their own graduate attributes and train students at them. For the discipline of chemistry in Australia, it is unclear how relevant these graduate attributes are to the different stakeholders of tertiary chemistry education: students, staff, and industries. The purpose of this study was to investigate the relevance of the graduate attributes to those three different stakeholders. Chemistry students and staff at the ANU, as well as industries in Canberra that employed chemists, were surveyed and interviewed and asked to rate the importance of and the student competence at the ANU graduate attributes for science. Results of this study showed that all stakeholder groups perceived the graduate attributes to be important, except some attributes were perceived more important than others - scientific analysis and problem solving were perceived as more important than communication, teamwork, and professionalism. Results also showed a discrepancy between students' perceived self-rated competence at the attributes...

Aerosol and precipitation chemistry measurements in a remote site in Central Amazonia: the role of biogenic contribution

Pauliquevis, T.; Lara, L. L.; Antunes, M. L.; Artaxo Netto, Paulo Eduardo
Fonte: COPERNICUS GESELLSCHAFT MBH; GOTTINGEN Publicador: COPERNICUS GESELLSCHAFT MBH; GOTTINGEN
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
394.9208%
In this analysis a 3.5 years data set of aerosol and precipitation chemistry, obtained in a remote site in Central Amazonia (Balbina, (1A degrees 55' S, 59A degrees 29' W, 174 m a.s.l.), about 200 km north of Manaus) is discussed. Aerosols were sampled using stacked filter units (SFU), which separate fine (d < 2.5 mu m) and coarse mode (2.5 mu m < d < 10.0 mu m) aerosol particles. Filters were analyzed for particulate mass (PM), Equivalent Black Carbon (BCE) and elemental composition by Particle Induced X-Ray Emission (PIXE). Rainwater samples were collected using a wet-only sampler and samples were analyzed for pH and ionic composition, which was determined using ionic chromatography (IC). Natural sources dominated the aerosol mass during the wet season, when it was predominantly of natural biogenic origin mostly in the coarse mode, which comprised up to 81% of PM10. Biogenic aerosol from both primary emissions and secondary organic aerosol dominates the fine mode in the wet season, with very low concentrations (average 2.2 mu g m(-3)). Soil dust was responsible for a minor fraction of the aerosol mass (less than 17%). Sudden increases in the concentration of elements as Al, Ti and Fe were also observed, both in fine and coarse mode (mostly during the April-may months)...

Nanoclusters Synthesized by Synchrotron Radiolysis in Concert with Wet Chemistry

Oyanagi, Hiroyuki; Orimoto, Yuuichi; Hayakawa, Kuniko; Hatada, Keisuke; Sun, Zhihu; Zhang, Ling; Yamashita, Kenichi; Nakamura, Hiroyuki; Uehara, Masato; Fukano, Atsuyuki; Maeda, Hideaki
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em 26/11/2014 EN
Relevância na Pesquisa
482.0508%
Wet chemical reduction of metal ions, a common strategy for synthesizing metal nanoparticles, strongly depends on the electric potential of the metal, and its applications to late transition metal clusters have been limited to special cases. Here, we describe copper nanoclusters grown by synchrotron radiolysis in concert with wet chemistry. The local structure of copper aggregates grown by reducing Cu(II) pentanedionate using synchrotron x-ray beam was studied in situ by x-ray absorption spectroscopy. A detailed analysis of the XANES and EXAFS spectra, compared with DFT calculations and full-potential non-muffin-tin multiple scattering calculations, identified the nanocluster as Cu13 with icosahedral symmetry. The novel “charged” nanoclusters tightly bound to electron-donating amido molecules, which formed as a result of photo-induced deprotonation of ligand amines, were stabilized by irradiation. Monodispersive deposition of nanoclusters was enabled by controlling the type and density of “monomers”, in remarkable contrast to the conventional growth of metallic nanoparticles.

Biological sulphate reduction with primary sewage sludge in an upflow anaerobic sludge bed (UASB) reactor - Part 2: Modification of simple wet chemistry analytical procedures to achieve COD and S mass balances

Poinapen,J; Ekama,GA; Wentzel,MC
Fonte: Water SA Publicador: Water SA
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2009 EN
Relevância na Pesquisa
589.8542%
The use of the conventional COD method to measure sulphide proved to be problematic due to the loss of hydrogen sulphide (H2S) during sample handling. For calibration of models based on mass balances, and operation of full-scale systems, it was imperative to develop simple wet chemistry analytical procedures for the accurate measurement of parameters like sulphide, COD, alkalinities and VFA in order to monitor BSR systems and achieve 100% COD and S mass balances. Three different analytical methods were investigated to minimise the loss of un-dissociated H2S. Method 1, which is the recommended Standard Methods COD test method, resulted in poor S mass balance (64-75%) due to loss of H2S during sample handling, mainly vacuum filtration. Method 2, in which 3 drops of 10 M NaOH are added immediately upon effluent sample collection to raise the pH to > 10 and converting un-dissociated H2S species into the HS- species resulted in minimal sulphide loss during sample vacuum filtration, dilution, mixing and standing. Method 3, in which a polyelectrolyte is added to the effluent sample to coagulate the organic particles with centrifugation for solid-liquid separation instead of vacuum filtration. Results from Method 3 showed an improvement in the S mass balance with respect to Method 1 - 91% against 75% without a long sample standing period and 88% against 65% with a long sample standing period. However...