The decolorization of Reactive Yellow 86 （RY 86）, one of reactive azo dyes, was investigated in the presence of Fenton reagent under solar light irradiation. The decolorization rate was strongly influenced by pH, in...The decolorization of Reactive Yellow 86 （RY 86）, one of reactive azo dyes, was investigated in the presence of Fenton reagent under solar light irradiation. The decolorization rate was strongly influenced by pH, initial concentrations of H202 and Fe（II）, and so on. An initial concentration of 40 mg/L was decolored more than 90% after 20 min under optimum conditions. The activation energy of the solar photo-Fenton reaction was 1.50 kJ/mol for RY 86 in the temperature range of 10-60℃. In the kinetic study, the rate constant of RY 86 with OH- radicals could be estimated to be 1.7 × 10^10 L/（mol.sec）. The decolorization efficiency of RY 86 under solar light irradiation was comparable to the artificial light irradiation. The decrease of TOC as a result of mineralization of RY 86 was observed during photo-Fenton process. The rate of RY 86 mineralization was about 83% under UV irradiation after 24 hr. The formation of chloride, sulfate, nitrate and ammonium ions as end-products was observed during the photocatalytic process. The decomposition of RY 86 gave two kinds of intermediate products. The degradation mechanism of RY 86 was proposed on the base of the identified intermediates.展开更多
The cometabolic roles of glucose were investigated in decolorization of an azo dye, Reactive Black 5, by yeast isolates, Debaryomyces polymorphus and Candida tropicalis. The results indicated that the dye degradation ...The cometabolic roles of glucose were investigated in decolorization of an azo dye, Reactive Black 5, by yeast isolates, Debaryomyces polymorphus and Candida tropicalis. The results indicated that the dye degradation by the two yeasts was highly associated with the yeast growth process and glucose presence in the medium. Color removal of 200 mg dye/L was increased from 76.4% to 92.7% within 60 h to 100% within 18-24 h with the increase of glucose from 5 to 10 g/L, although the activity of manganese dependent peroxidase （MnP） decreased by 2-8 times in this case. Hydrogen peroxide of 233.3 μg/L was detected in 6 h in D. polymorphus culture. The cometabolic functions of glucose and hydrogen peroxide could be also confirmed by the further color removals of 95.8% or 78,9% in the second cycle of decolorization tests in which 7 g glucose/L or 250 μg H202/L was superadded respectively together with 200 mg dye/L.展开更多
The objective of the study was to investigate the presence and the activity of quantum dots nanoparticles in colored wastewaters.The special interest is devoted to the investigation of their role in the typical treatm...The objective of the study was to investigate the presence and the activity of quantum dots nanoparticles in colored wastewaters.The special interest is devoted to the investigation of their role in the typical treatment of water or wastewater,studying their influence on the effectiveness of applied treatments methods.The standard chemical processes for water treatment and disinfection （direct UV photolysis and direct ozonation） were applied for the degradation of colored organic pollutant,reactive azo dye,in the presence/absence of CdSe/ZnS core-shells quantum dots.The obtained results indicated that investigated nanoparticles inhibit the overall efficiency of applied processes,especially in the case of direct UV photolysis,although catalytic effect might be expected in part due to the semiconductor nature of quantum dots.Such results lead to a conclusion that CdSe/ZnS nanoparticles behave as additional pollutants in the system.They should be removed from the system prior the treatment,because their presence could decrease the efficiency,i.e.,prolong the time of treatment and correspondingly increase the costs of the treatment process.展开更多
基金supported by the Ministry of Education,Culture,Sports,Science,and Technology of Japan
文摘The decolorization of Reactive Yellow 86 （RY 86）, one of reactive azo dyes, was investigated in the presence of Fenton reagent under solar light irradiation. The decolorization rate was strongly influenced by pH, initial concentrations of H202 and Fe（II）, and so on. An initial concentration of 40 mg/L was decolored more than 90% after 20 min under optimum conditions. The activation energy of the solar photo-Fenton reaction was 1.50 kJ/mol for RY 86 in the temperature range of 10-60℃. In the kinetic study, the rate constant of RY 86 with OH- radicals could be estimated to be 1.7 × 10^10 L/（mol.sec）. The decolorization efficiency of RY 86 under solar light irradiation was comparable to the artificial light irradiation. The decrease of TOC as a result of mineralization of RY 86 was observed during photo-Fenton process. The rate of RY 86 mineralization was about 83% under UV irradiation after 24 hr. The formation of chloride, sulfate, nitrate and ammonium ions as end-products was observed during the photocatalytic process. The decomposition of RY 86 gave two kinds of intermediate products. The degradation mechanism of RY 86 was proposed on the base of the identified intermediates.
基金This work was supported by the Program for New Century Excellent Talents in University in China(No.NCET-05-0612)the National Natural Science Foundation of China(No.20677014).
文摘The cometabolic roles of glucose were investigated in decolorization of an azo dye, Reactive Black 5, by yeast isolates, Debaryomyces polymorphus and Candida tropicalis. The results indicated that the dye degradation by the two yeasts was highly associated with the yeast growth process and glucose presence in the medium. Color removal of 200 mg dye/L was increased from 76.4% to 92.7% within 60 h to 100% within 18-24 h with the increase of glucose from 5 to 10 g/L, although the activity of manganese dependent peroxidase （MnP） decreased by 2-8 times in this case. Hydrogen peroxide of 233.3 μg/L was detected in 6 h in D. polymorphus culture. The cometabolic functions of glucose and hydrogen peroxide could be also confirmed by the further color removals of 95.8% or 78,9% in the second cycle of decolorization tests in which 7 g glucose/L or 250 μg H202/L was superadded respectively together with 200 mg dye/L.
基金both the US Army Engineer Research and Development Center,Vicksburg,MS,USA (throughout DOD contracts # W912HZ-06-C-0057 and # W912HZ-06-C-096)Ministry of Science,Education and Sports of Republic of Croatia (Project #125-1253092-1981) for funding this work
文摘The objective of the study was to investigate the presence and the activity of quantum dots nanoparticles in colored wastewaters.The special interest is devoted to the investigation of their role in the typical treatment of water or wastewater,studying their influence on the effectiveness of applied treatments methods.The standard chemical processes for water treatment and disinfection （direct UV photolysis and direct ozonation） were applied for the degradation of colored organic pollutant,reactive azo dye,in the presence/absence of CdSe/ZnS core-shells quantum dots.The obtained results indicated that investigated nanoparticles inhibit the overall efficiency of applied processes,especially in the case of direct UV photolysis,although catalytic effect might be expected in part due to the semiconductor nature of quantum dots.Such results lead to a conclusion that CdSe/ZnS nanoparticles behave as additional pollutants in the system.They should be removed from the system prior the treatment,because their presence could decrease the efficiency,i.e.,prolong the time of treatment and correspondingly increase the costs of the treatment process.
