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A fast and simple method for determination of α, β, γ-hexachlorocyclohexanes (HCHs) in water using activated carbon fiber-solid phase microextraction (ACF-SPME) were pressented. Results showed the performance of adsorption and desorption of three HCHs on ACF were excellent. A wide linear range from 10 to 100 μg/L and detection limits of the ng/L level were obtained using ACF-SPME with GC-MS in selected ion monitoring (SIM) acquisition mode. The proposed method was also successfully applied for determination of three HCHs in tap water. Compared to commercial fibers, ACF showed some advantages such as better resistance to solvents, higher thermal stability, long lifetime and lower cost. The data demonstrated that GC-MS with ACF-SPME is well suitable for the analysis of HCHs in water. [ABSTRACT FROM AUTHOR]

Abstract: This paper explores the degradation of a model pollutant, 1-diazo-2-naphthol-4-sulfonic acid (1,2,4-Acid), by an advanced oxidation process that combines electrochemical degradation and Bi2Fe4O9 (BFO) oxidation. Experiments were done using a gas-diffusion cathode to produce in situ hydrogen peroxide by oxygen reduction. Column crystal semiconductor Bi2Fe4O9 was synthesized and used as a novel catalyst in the combined system. It was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Comparative experiment in two separated systems (BFO/H2O2 and BFO/Electrolysis) was conducted to determine the mechanism involved in the process. The effect of operating conditions such as applied current, solution pH, catalyst dosage on the efficacy of the process was investigated. It is shown that 1,2,4-Acid and its products can be effectively degraded by the OH produced by the reaction between BFO and the electro-generated H2O2, which was further being confirmed with the electron spin resonance spin-trapping technique. Hydroxyl radicals generated in the process that led to the complete and rapid elimination of total organic carbon was observed even at low catalyst loadings. In this system, almost a complete removal of COD (89%) was achieved after 200min using 1.0gL−1 of BFO, whereas at the same time, only 39% and 32% of COD was removed by an individual process alone (electrochemical degradation and BFO adsorption, respectively). In this combined system, BFO has the principle role of adsorbing the initial substance on the surface of catalyst and catalyzing the electro-generated H2O2 to form active hydroxyl radicals. The LC-(ESI)-TOF-MS analysis indicated that the mineralization occurred simultaneous with the destruction of naphthalene ring, and 1,2,4-Acid was oxidized to colourless intermediates (mainly phthalic acid, small carbonyl species) and then to carbon dioxide. [Copyright &y& Elsevier]

To investigate the perennial effect of environment adjustment layers on the interior environment and nitrogen transformation in anaerobic bioreactor landfills, three sets of simulated anaerobic bioreactor landfills and two kinds of environment adjustment layers of mineralized refuse with heavy calcium carbonate (R2) and mineralized refuse with natural zeolites (R3) were designed and established. The degradation and transformation of nitrogen in waste and leachate had been monitored for 390 days. The results showed that, the value orders of pH, alkalinity, oxidation reduction potential and moisture content (MS) were pH(R2) > pH(R3) > pH(R1), alkalinity (R2) > alkalinity (R3) > alkalinity (R1), Eh(R2) < Eh(R3) < Eh(R1) and MS(R3) > MS(R2) > MS(R1). In R1, R2 and R3, the degradation rates of total nitrogen, ammonia nitrogen, nitrate nitrogen in waste were 79.2%, 82.3% and 88.5%, 48.3%, 60.1% and 67.7%, 38.5%, 44.2% and 53.4%, respectively. Concentration comparison results of total nitrogen, ammonia nitrogen and nitrate nitrogen in leachate were TN(R3) < TN(R2) < TN(R1)、NH 4 + -N(R3) < NH 4 + -N(R1) < NH 4 + -N(R2)NO 3 - -N(R3) < NO 3 - -N(R2) < NO 3 - -N(R1). Additionally, both of mineralized refuse with heavy calcium carbonate and mineralized refuse with natural zeolites could long-term adjust and optimize the interior environment of anaerobic bioreactor landfills for the degradation and conversion of nitrogen. Mineralized waste with natural zeolite could not only promote the degradation and transformation of nitrogen components in waste and leachate, but also control the accumulation of ammonia nitrogen through leachate recirculation.

A fast and simple method for determination of alpha, beta, gamma-hexachlorocyclohexanes (HCHs) in water using activated carbon fiber-solid phase microextraction(ACF-SPME) were studied. Results showed the performance of adsorption and desorption of three HCHs on ACF were excellent. A wide linear range from 10 to 100 microg/L and detection limits of the ng/L level were obtained using ACF-SPME with GC-MS in selected ion monitoring(SIM) acquisition mode. The proposed method was also successfully applied for determination of three HCHs in tap water. Compared to commercial fibers, ACF showed some advantages such as better resistance to solvents, higher thermal stability, longer lifetime and lower cost. The data demonstrated that GC-MS with ACF-SPME is well suitable for the analysis of HCHs in water.

Aerobic heterotrophic granular sludge was cultivated in a sequencing batch shaking reactor (SBSR) in which a synthetic wastewater containing glucose as carbon source was fed. The characteristics of the aerobic granules were investigated. Compared with the conventional activated sludge flocs, the aerobic granules exhibit excellent physical characteristics in terms of settleability, size, shape, biomass density, and physical strength. Scanning electron micrographs revealed that in mature granules little filamentous bacteria could be found, rod-shaped and coccoid bacteria were the dominant microorganisms.