The emulsion liquid membrane technique was used to extract amino-J acid from industrial dye *** effects of stirring speed,ratio of the emulsion to water(Rew),ratio of the oil to internal phase(Roi)and membrane phase c...
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The emulsion liquid membrane technique was used to extract amino-J acid from industrial dye *** effects of stirring speed,ratio of the emulsion to water(Rew),ratio of the oil to internal phase(Roi)and membrane phase components on the extraction rate were investigated and *** results showed that the extraction rate of amino-J acid approached 97% when the stirring speed was 300 r/min,Rew 1:6,Roi 1:1,trioctylamine(TOA)3 mL/100 mL kerosene,and methyl?didecyle?alcohol?acrylate(LMA-2)3 g/100 mL kerosene,*** extraction rate had not changed with the oil phase reused for times.
This paper investigated the effects of β-cyclodextrins （I3-CD） and its two derivatives, hydroxypropyl-β-cyclodextrin （HPCD） and carboxymethyl-β-cyclodextrin （CMCD）, on the solubility and biodegradation of 2-n...
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This paper investigated the effects of β-cyclodextrins （I3-CD） and its two derivatives, hydroxypropyl-β-cyclodextrin （HPCD） and carboxymethyl-β-cyclodextrin （CMCD）, on the solubility and biodegradation of 2-nitrophenyl by an A cinetbacter sp. Results showed that β-CD, HPCD and CMCD could not be utilized by A cinetbacter sp. as sole carbon source and none of the CDs had toxic effects on the growth of the bacteria in the experiments; all the CDs could enhance the apparent solubility and accelerate the biodegradation of 2-nitrobipheny. It showed that biodegradation-accelerating effects of CDs on 2-nitrobiphenyl were correlated with their solubility-enhancing effects. Among three CDs investigated, CMCD had the most obvious effects both on the apparent solubility and the biodegradation, followed by β-CD and HPCD.
TiO2 nanotube precursor was synthesized by the hydrothermal reaction of TiO2 powders with NaOH solution and the properties of the nanotube materials were tuned using different post-treatments. Transmission electron mi...
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TiO2 nanotube precursor was synthesized by the hydrothermal reaction of TiO2 powders with NaOH solution and the properties of the nanotube materials were tuned using different post-treatments. Transmission electron microscopic （TEM） observation revealed that the nanotube could be obtained by either a direct rinse with acid solution or rinse with distilled water followed by acid solution. The results of X-ray diffraction （XRD） and inductively coupled plasma （ICP） analysis indicated that the nanotube material was composed of H2Ti2O5·H2O. In addition, the photocatalytic activities of the resulting catalysts were found to be strongly dependent on the post-treatment. The results of the photocatalytic reaction showed that the degradation of Acid-red 3B dye fitted pseudo-zero-order kinetics and TiO2 nanotube prepared under direct rinse with acid solution exhibited a higher catalytic efficiency compared to other catalysts.
Reactions between humic acid solutions and excessive ClO2 or Cl2 have been investigated. Under various experimental conditions, the removal efficiency of TOC, UV254 and A140 from humic acid solutions were examined. Th...
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Reactions between humic acid solutions and excessive ClO2 or Cl2 have been investigated. Under various experimental conditions, the removal efficiency of TOC, UV254 and A140 from humic acid solutions were examined. The relationship between the removal efficiency and the consumption of ClO2 or Cl2 was discussed. The results showed that the maximum demand of ClO2 was 2.19 mg/mg TOC for the humic acid solution under the experimental conditions, and that of Cl2 was 1.88 mg/mg TOC. The variation tendency of ClO2 consumption was similar to that of Cl2. TOC of humic acid solutions decreased 15.2% and 15.6% after the reaction with ClO2 or Cl2 respectively. Under the experimental conditions, 21.4% of unsaturated bonds and 52.8% of humic acid color were removed by ClO2 in 168 h. As for Cl2, removal efficiency of unsaturated bonds and humic acid color were 16.8% and 41.7% respectively. Larger molecules from humic acid were oxidized to smaller molecules by ClO2 and Cl2. Higher oxidation potential of ClO2 than that of Cl2 was also indicated by variation of UV254/A410 ratios. The similar tendency, that exhibited faster variation in the initial 24 h, existed for all the research factors.
Simultaneous nitrification and denitrification （SND） effect and phosphor removal were investigated in a one-staged aerobic submerged membrane bioreactor on pilot-scale with mixed liquor suspended solids （MLSS） 19-...
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Simultaneous nitrification and denitrification （SND） effect and phosphor removal were investigated in a one-staged aerobic submerged membrane bioreactor on pilot-scale with mixed liquor suspended solids （MLSS） 19--20 g/L. The effects of DO concentration, sludge floc size distribution on SND were studied. Test results suggested that SND was successfully performed in the membrane bioreactor （MBR） and about 70% total nitrogen removal efficiency was achieved when DO concentration was set to 0.2-- 0.3 mg/L. The main mechanisms governing SND were the suitable sludge floc size and the low DO concentration which was caused by low oxygen transfer rate with such a high MLSS concentration in the MBR. In the meantime, phosphor removal was also studied with polymer ferric sulfate （PFS） addition and 14 mg/L dosage of PFS was proper for the MBR to remove phosphor. PFS addition also benefited the MBR operation owing to its reduction of extracellular polymer substances （EPS） of mixed liquor.
Adverse effects on the environment and high persistence in the microbial degradation and environmental fate of polycyclic aromatic hydrocarbons (PAHs) are motivating interest. Many soil microorganisms can degrade PAHs...
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Adverse effects on the environment and high persistence in the microbial degradation and environmental fate of polycyclic aromatic hydrocarbons (PAHs) are motivating interest. Many soil microorganisms can degrade PAHs and use various metabolic pathways to do so. However, both the physio-chemical characteristics of compounds as well as the physical, chemical, and biological properties of soils can drastically influence the degradation capacity of naturally occurring microorganisms for field bioremediation. Modern biological techniques have been widely used to promote the efficiency of microbial PAH-degradation and make the biodegradation metabolic pathways more clear. In this review microbial degradation of PAHs in soil is discussed, with emphasis placed on the main degradation pathways and the environmental factors affecting biodegradation.
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