Influence of interfering dissolved organic matter on the determination of hydrogen peroxide by a colorimetric method based on the peroxidase catalyzed oxidation of N,N-diethyl-p-phenylenediamine.

The influence of dissolved organic matter (DOM), such as humic acid (HA) and hydroxybenzoic acids, on the determination of H(2)O(2) via a colorimetric method using N,N-diethyl-p-phenylenediamine (DPD) was examined. The influence of DOM on absorbance decay at 551 nm, which represents the wavelength for maximum absorption of the oxidized species of DPD (DPD(+)), were investigated in detail. Significant decrease in the absorbance at 551 nm was observed in the presence of HA and gallic acid.

Microalgal cultivation in a solution recovered from the low-temperature catalytic gasification of the microalga.

Microalgal cultivation in a solution recovered from the low-temperature catalytic gasification of the microalga itself was studied. The growth of Chlorella vulgaris in 75-300-fold diluted recovered solution containing phosphate, magnesium ions and micro-elements was comparable to that in the standard culture medium. It was suggested that C.

Characterization of lighted upflow anaerobic sludge blanket (LUASB) method under sulfate-rich conditions.

Growth of phototrophic bacteria was induced from granules in a lighted upflow anaerobic sludge blanket (LUASB) reactor supplied with an organic-acid-based medium containing 141.7 mg S.l(-1) of SO4(2-) under light conditions (100 microE.

Organic acid consumption of phototrophic bacteria in a lighted upflow anaerobic sludge blanket reactor.

It was previously suggested that a population of phototrophic bacteria, Rhodopseudomonas palustris strain RN1 and Blastochloris sulfoviridis strain GN1 could be induced from granules in a lighted upflow anaerobic sludge blanket (LUASB) reactor. The present study showed that both strains RN1 and GN1 could use acetate, propionate, butyrate, and lactate as electron donors under anaerobic light conditions. The composition of organic acids in the effluent from the LUASB reactor was studied to investigate competitive consumption between acetogenic bacteria, methanogens, and phototrophic bacteria in the reactor.

Isolation and characterization of phototrophic bacteria growing in lighted upflow anaerobic sludge blanket reactor.

Two strains of phototrophic bacteria were isolated from the effluent of a lighted upflow anaerobic sludge blanket (LUASB) reactor. Their 16S rRNA gene sequences and phenotypic characteristics suggested that two isolates were Rhodopseudomonas palustris and Blastochloris sulfoviridis strains.

Effects of glucose addition and light on current outputs in photosynthetic electrochemical cells using Synechocystis sp. PCC6714.

The effects of glucose addition and light on the current outputs in electrochemical cells using a cyanobacterium Synechocystis sp. PCC6714 were investigated under photo- and chemoheterotrophical conditions. The addition of glucose to the anode solutions of the electrochemical cells resulted in a rapid increase in the current outputs under both light and dark conditions.

Wastewater treatment and poly-beta-hydroxybutyrate production using lighted upflow anaerobic sludge blanket method.

We investigated the performance of a lighted upflow anaerobic sludge blanket (LUASB) reactor for wastewater treatment and poly-beta-hydroxybutyrate (PHB) production. Phototrophic bacteria were induced from UASB (upflow anaerobic sludge blanket) granules under light conditions (100 microE.m(-2).

Treatment of liquid fraction separated from liquidized food waste in an upflow anaerobic sludge blanket reactor.

Thermochemical liquidization as a pretreatment for anaerobic digestion of food waste was studied using a laboratory-scale upflow anaerobic sludge blanket (UASB) reactor for a period of 82 d. Model food waste (approximately 90 wt% moisture content) was thermochemically liquidized at 175 degrees C for 1 h. The liquidized food waste was separated into a solid phase (6-10 wt%) and a liquid phase (85-89 wt%).

Determination of selenium compounds in urine by high-performance liquid chromatography--inductively coupled plasma mass spectrometry.

Selenium species, selenite, selenate, selenomethionine (Semet), seneloethionine (Seet) and trimethylselenonium ion (TmSe) were separated in aqueous solution using a gel-permeation (polyvinyl alcohol-based resin) GS-220 column by eluting with 25 mM tetramethylammonium hydroxide and 25 mM malonic acid at pH 7.9. The GS-220 column coupled with inductively coupled plasma mass spectrometry was used for the separation, identification, and quantification of selenium compounds present in certified reference material (CRM) No.

Effects of copper chloride on formation of polychlorinated dibenzofurans in model waste incineration in a laboratory-scale fluidized-bed reactor.

Combustion experiments in a laboratory-scale fluidized-bed reactor have been performed to clarify the effects of copper chloride as a catalyst on polychlorinated dibenzofurans (PCDFs) formation in municipal waste incineration. We used model wastes with and without copper chloride (CuCl2 x 2H2O) as a catalyst, both of which contained polyvinyl chloride (PVC) as a chlorine source. Combustion temperature was set to 900 degrees C, and the amount of air supplied was twice as much as the theoretical amount.

Treatment system for solid matrix contaminated with fluoranthene. II--Recirculating photodegradation technique.

A laboratory-scale solar reactor and photodegradation technique were developed to enhance the degradation process of fluoranthene. Fluoranthene was used in this study to represent toxic polycyclic aromatic hydrocarbons (PAHs) that are persistent in the environment. The extracted fluoranthene from soil in organic solvent (EFOS) and hydrogen peroxide (H2O2) were pumped from a 100 ml vessel into a solar glass cell coated with titanium dioxide (TiO2) at 80 microl min(-1).

Treatment system for solid matrix contaminated with fluoranthene. I--Modified extraction technique.

A laboratory-scale ultrasonication technique was developed for fluoranthene extraction from soils and sediments where the utilized organic solvent would be recovered after the extraction process. Therefore, the remedied soils and sediments would be free from toxicant and trace of added chemicals. The developed ultrasonication technique outlined here is an integrated part of a complete remediation system consisting of extraction and solar detoxification reactors.

Validation of modeling approach to evaluate congener-specific concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans in air and soil near a solid waste incinerator.

A concise modeling approach using long-term averaged meteorological data was developed to estimate site-specific concentrations of congeners of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) near a solid waste incinerator. This approach consists of calculation of atmospheric dispersion, dry and wet deposition of gaseous and particle-bound congeners, and non-steady-state concentrations in soil. The predictability of this approach was evaluated by comparison of calculated concentrations of congeners in soil with those measured at eight locations near a municipal solid waste incinerator (MSWI).

Correlation of polychlorinated naphthalenes with polychlorinated dibenzofurans formed from waste incineration.

Isomer composition of polychlorinated naphthalenes (PCNs) was measured for municipal waste incinerator fly ash samples and for emission samples produced from soot and copper-deposit experiments conducted at the United States Environmental Protection Agency (US-EPA). Two types of PCN isomer patterns were identified. One pattern contained specific PCN isomers in which chlorine atoms are substituted as if the peri(alpha-) position were dechlorinated from the higher chlorinated PCNs one by one.

Simultaneous removal of phenol and ammonia by an activated sludge process with cross-flow filtration.

Attempts were made for removing ammonia from synthetic wastewater under the presence of phenol, which is inhibitory to nitrification, by using a single-stage activated sludge process with cross-flow filtration. Activated sludge biomass which had been acclimated with phenol for over 15 years was used for the inoculum, and synthetic wastewater was continuously supplied to the process retaining biomass at 8000 mg VSS l(-1). Phenol was completely removed, and ammonia was simultaneously nitrified to nitrate; nitrification rate reached 200 mg N l(-1) d(-1) when phenol was removed at a rate up to 300 mg l(-1) d(-1).

Presence of nitrate-accumulating sulfur bacteria and their influence on nitrogen cycling in a shallow coastal marine sediment.

Nitrate flux between sediment and water, nitrate concentration profile at the sediment-water interface, and in situ sediment denitrification activity were measured seasonally at the innermost part of Tokyo Bay, Japan. For the determination of sediment nitrate concentration, undisturbed sediment cores were sectioned into 5-mm depth intervals and each segment was stored frozen at -30 degrees C. The nitrate concentration was determined for the supernatants after centrifuging the frozen and thawed sediments.

Role of anions on heavy metal sorption of a cellulose modified with poly(glycidyl methacrylate) and polyethyleneimine.

The influence of anions on the equilibrium and kinetic uptake of heavy metals from an aqueous solution by a novel nitrogen-type chelating adsorbent was evaluated. Equilibrium experiments revealed that stoichiometric amounts of metals and anions are adsorbed by the resin. Kinetic studies showed that during the initial stage of adsorption, the anions are adsorbed by the adsorbent prior to the metal ions.

Improved performance of a chitosan-based adsorbent for the sequestration of some transition metals.

Polyethyleneimine (PEI) was chemically introduced onto chitosan by its reaction with epoxide groups of grafted poly(glycidyl methacrylate) (poly(GMA)) chains for enhanced metal chelating properties and improved physical stability in acidic conditions. Graft polymerization of poly(GMA) onto chitosan was initiated by Ce(IV) ammonium nitrate (CAN). Infrared spectroscopy revealed the presence of significant epoxide groups to confirm the success of both grafting and amination stages.

Synthesis and characterization of ruthenium(II) molecular assemblies for photosensitization of nanocrystalline TiO2: utilization of hydroxyl grafting mode.

New Ru polypyridine complexes [(bpy)2Ru(L)]2+, where bpy = 2,2'-bipyridine and L = dipyrido[3,2-a:2',3'-c]-phenazine-2-carboxylic acid (dppzc), dipyrido[3,2-f:2',3'-h]quinoxaline-2,3-dicarboxylic acid (dpq(COOH)2), 3-hydroxydipyrido[3,2-f:2',3'-h]quinoxaline-2-carboxylic acid (dpq(OHCOOH)), 2,3-dihydroxydipyrido[3,2-f:2',3'-h]quinoxaline (dpq(OH)2), and [(L')Ru(dppzc)2]2+, where L' = bpy and 1,10-phenanthroline (phen), have been synthesized, characterized, and anchored to nanocrystalline TiO2 electrodes for light to electrical energy conversion in regenerative photoelectrochemical cells with I-/I2 acetonitrile electrolyte. These sensitizers have intense metal-to-ligand charge-transfer (MLCT) bands centered at approximately 450 nm. The effect of pH on the absorption and emission spectra of these complexes consisting of protonatable ligands has been investigated in water by spectrophotometric titration.

Hydrodynamic Shape and Size of Khafji Asphaltene in Benzene.

Three different semiaxes of Khafji asphaltene, assumed to be an ellipsoidal model, were calculated from the viscosity of a benzene solution of the asphaltene and from Harding's relationship between the axial ratio of an ellipsoid and the constant φ in Einstein's viscosity formula. The constant φ for carbon disulfide solution with fullerene showed that Einstein's formula was applicable to the benzene solution. The asphaltene consists of double layers with semiaxes of 31.

A quantitative extraction method for the determination of trace amounts of both butyl- and phenyltin compounds in sediments by gas chromatography-inductively coupled plasma mass spectrometry.

A simple and reliable extraction method was developed for quantitative determination of both butyl- and phenyltin compounds in sediments by capillary gas chromatography combined with inductively coupled plasma mass spectrometry (GC-ICP-MS). Both types of organotin compounds were extracted quantitatively from sediment by mechanical shaking into tropolone-toluene and HCl-methanol. After phase separation and pH adjustment, these organotins were ethylated with sodium tetraethylborate.

Anaerobic transformation of chlorophenols in methanogenic sludge unexposed to chlorophenols.

Transformation of all 19 chlorophenol (CP) isomers was investigated in a laboratory anaerobic methanogenic sludge that had not been exposed to synthetic chemicals. Concentration of CP was analyzed over time to calculate disappearance rate constants using first-order reaction kinetics and all possible CP degradation pathways were estimated. The rate constants ranged between 0.

Sound propagation and speech transmission in a branching underground tunnel.

The characteristics of sound propagation and speech transmission along a tunnel with a "T" intersection were investigated. At receivers within sight of the sound source, low frequencies were mainly attenuated around the intersection than high frequencies. At receivers out of sight of the source, high frequencies were extensively attenuated.