Mutatox is a new genotoxicity bioassay which uses as the endpoint the bioluminescence produced on reversion of a dark strain of the marine bacterium Vibrio fischeri ±S9.Reversion can occur by several mechanisms, ...Mutatox is a new genotoxicity bioassay which uses as the endpoint the bioluminescence produced on reversion of a dark strain of the marine bacterium Vibrio fischeri ±S9.Reversion can occur by several mechanisms, including base substitution, frame-shift, SOS induction, and DNA intercalation. For screening, Mutatox provides many advantages over the Salmonella trphimurium (Ames) assay: it requires minimal sterility, employs a shorter incubation period, and does not require culture maintenance. Eighteen organic chemicals (phenol, polynuclear aromatic hydrocarbons, nitrotoluenes, others), Na3PO4, and 4 genotoxic metals (Cu2+, Ni2+, As3+, Cd2+) were tested. Most of the organic compounds positive in S. typhimurium assays were positive in Mutatox. None of the metals was genotoxic in V. fischeri, possibly due to poor uptake from the saline medium展开更多
Oxygenated volatile organic compounds（OVOCs） emitted from orange wastes during aerobic decomposition were investigated in a laboratory-controlled incubator for a period of two months. Emission of total OVOCs（TOVOCs...Oxygenated volatile organic compounds（OVOCs） emitted from orange wastes during aerobic decomposition were investigated in a laboratory-controlled incubator for a period of two months. Emission of total OVOCs（TOVOCs） from orange wastes reached 1714 mg/dry kg（330 mg/wet kg）. Ethanol, methanol, ethyl acetate, methyl acetate, 2-butanone and acetaldehyde were the most abundant OVOC species with shares of 26.9%, 24.8%, 20.3%, 13.9%, 2.8%and 2.5%, respectively, in the TOVOCs released. The emission fluxes of the above top five OVOCs were quite trivial in the beginning but increased sharply to form one ＂peak emission window＂ with maximums at days 1-8 until leveling off after 10 days. This type of ＂peak emission window＂ was synchronized with the CO2 fluxes and incubation temperature of the orange wastes, indicating that released OVOCs were mainly derived from secondary metabolites of orange substrates through biotic processes rather than abiotic processes or primary volatilization of the inherent pool in oranges. Acetaldehyde instead had emission fluxes decreasing sharply from its initial maximum to nearly zero in about four days,suggesting that it was inherent rather than secondarily formed. For TOVOCs or all OVOC species except 2-butanone and acetone, over 80% of their emissions occurred during the first week, implying that organic wastes might give off a considerable amount of OVOCs during the early disposal period under aerobic conditions.展开更多
TOC and color in the bleaching effluent from straw pulp paper process could not reach draining standard after its treatment by a biochemical process. In this study, advanced treatment by integrated micro-electrolysis ...TOC and color in the bleaching effluent from straw pulp paper process could not reach draining standard after its treatment by a biochemical process. In this study, advanced treatment by integrated micro-electrolysis （Fe^0） method and Fenton-like process was investigated under various conditions, i.e. pH, Fe/C ratio, initial I-I2O2 concentration and carrier gas. Results showed that Fe/C ratio（V/V = 1.5）, larger H2O2 dosage around 50 rag/L, lower pH（pH= 3） turned out to be particularly efficient. Temperature was a key parameter, remarkably increasing reaction rates. Carrier air not only improved reaction efficiency, but also saved H2O2 dosage. Chlorinated organic compounds could be reductive dechlorinated by Fe^0 reaction and oxidated by OH produced from Fenton process. The combination of Fe^0 and H2O2 reactions had been proved to be highly effective for the advanced treatment of such a type of wastewaters, and important advantages concerning the application in the study.展开更多
Adsorption is the most widely used technology for the removal of indoor volatile organic compounds （VOCs）. However, existing adsorbent-based technologies are inadequate to meet the regulatory requirement, due to the...Adsorption is the most widely used technology for the removal of indoor volatile organic compounds （VOCs）. However, existing adsorbent-based technologies are inadequate to meet the regulatory requirement, due to their limited adsorption capacity and efficiency, especially under high relative humidity （RH） conditions. In this study, a series of new porous clay heterostructure （PCH） adsorbents with various ratios ofmicropores to mesopores were synthesized, characterized and tested for the adsorp- tion of acetaldehyde and toluene. Two of them, PCH25 and PCH50, exhibited markedly improved adsorption capabil- ity, especially for hydrophilic acetaldehyde. The improved adsorption was attributed to their large micropore areas and high micropore-to-mesopore volume ratios. The amount of acetaldehyde adsorbed onto PCH25 at equilibrium reached 62.7 mg. g-l, eight times as much as the amount adsorbed onto conventional activated carbon （AC）. Even at a high RH of 80%, PCH25 removed seven and four times more of the acetaldehyde than AC and the unmodified raw PCHs did, respectively. This new PCH optimized for their high adsorption and resistance to humidity has promising applications as a cost-effective adsorbent for indoor air purification.展开更多
文摘Mutatox is a new genotoxicity bioassay which uses as the endpoint the bioluminescence produced on reversion of a dark strain of the marine bacterium Vibrio fischeri ±S9.Reversion can occur by several mechanisms, including base substitution, frame-shift, SOS induction, and DNA intercalation. For screening, Mutatox provides many advantages over the Salmonella trphimurium (Ames) assay: it requires minimal sterility, employs a shorter incubation period, and does not require culture maintenance. Eighteen organic chemicals (phenol, polynuclear aromatic hydrocarbons, nitrotoluenes, others), Na3PO4, and 4 genotoxic metals (Cu2+, Ni2+, As3+, Cd2+) were tested. Most of the organic compounds positive in S. typhimurium assays were positive in Mutatox. None of the metals was genotoxic in V. fischeri, possibly due to poor uptake from the saline medium
基金supported by the Ministry of Science and Technology of China (No. 2012IM030700)the National Natural Science Foundation of China (Nos. 41025012, U0833003, 41273095 and 41103067)
文摘Oxygenated volatile organic compounds（OVOCs） emitted from orange wastes during aerobic decomposition were investigated in a laboratory-controlled incubator for a period of two months. Emission of total OVOCs（TOVOCs） from orange wastes reached 1714 mg/dry kg（330 mg/wet kg）. Ethanol, methanol, ethyl acetate, methyl acetate, 2-butanone and acetaldehyde were the most abundant OVOC species with shares of 26.9%, 24.8%, 20.3%, 13.9%, 2.8%and 2.5%, respectively, in the TOVOCs released. The emission fluxes of the above top five OVOCs were quite trivial in the beginning but increased sharply to form one ＂peak emission window＂ with maximums at days 1-8 until leveling off after 10 days. This type of ＂peak emission window＂ was synchronized with the CO2 fluxes and incubation temperature of the orange wastes, indicating that released OVOCs were mainly derived from secondary metabolites of orange substrates through biotic processes rather than abiotic processes or primary volatilization of the inherent pool in oranges. Acetaldehyde instead had emission fluxes decreasing sharply from its initial maximum to nearly zero in about four days,suggesting that it was inherent rather than secondarily formed. For TOVOCs or all OVOC species except 2-butanone and acetone, over 80% of their emissions occurred during the first week, implying that organic wastes might give off a considerable amount of OVOCs during the early disposal period under aerobic conditions.
文摘TOC and color in the bleaching effluent from straw pulp paper process could not reach draining standard after its treatment by a biochemical process. In this study, advanced treatment by integrated micro-electrolysis （Fe^0） method and Fenton-like process was investigated under various conditions, i.e. pH, Fe/C ratio, initial I-I2O2 concentration and carrier gas. Results showed that Fe/C ratio（V/V = 1.5）, larger H2O2 dosage around 50 rag/L, lower pH（pH= 3） turned out to be particularly efficient. Temperature was a key parameter, remarkably increasing reaction rates. Carrier air not only improved reaction efficiency, but also saved H2O2 dosage. Chlorinated organic compounds could be reductive dechlorinated by Fe^0 reaction and oxidated by OH produced from Fenton process. The combination of Fe^0 and H2O2 reactions had been proved to be highly effective for the advanced treatment of such a type of wastewaters, and important advantages concerning the application in the study.
文摘Adsorption is the most widely used technology for the removal of indoor volatile organic compounds （VOCs）. However, existing adsorbent-based technologies are inadequate to meet the regulatory requirement, due to their limited adsorption capacity and efficiency, especially under high relative humidity （RH） conditions. In this study, a series of new porous clay heterostructure （PCH） adsorbents with various ratios ofmicropores to mesopores were synthesized, characterized and tested for the adsorp- tion of acetaldehyde and toluene. Two of them, PCH25 and PCH50, exhibited markedly improved adsorption capabil- ity, especially for hydrophilic acetaldehyde. The improved adsorption was attributed to their large micropore areas and high micropore-to-mesopore volume ratios. The amount of acetaldehyde adsorbed onto PCH25 at equilibrium reached 62.7 mg. g-l, eight times as much as the amount adsorbed onto conventional activated carbon （AC）. Even at a high RH of 80%, PCH25 removed seven and four times more of the acetaldehyde than AC and the unmodified raw PCHs did, respectively. This new PCH optimized for their high adsorption and resistance to humidity has promising applications as a cost-effective adsorbent for indoor air purification.
