A comparative study of treatment of simulated wastewater containing Reactive Red 195 using zero-valent iron/activated carbon （ZVI/AC）, microwave discharge electrodeless lamp/sodium hypochlorite （MDEL/NaCIO） and th...A comparative study of treatment of simulated wastewater containing Reactive Red 195 using zero-valent iron/activated carbon （ZVI/AC）, microwave discharge electrodeless lamp/sodium hypochlorite （MDEL/NaCIO） and the combination of ZVI/AC- MDEL/NaCIO was conducted. The preliminary results showed the two steps method of ZVI/AC-MDEL/NaCIO had much higher degradation efficiency than both single steps. The final color removal percentage was nearly up to 100% and the chemical oxygen demand reduction percentage was up to approximately 82%. The effects of operational parameters, including initial pH value of simulated wastewater, ZVI/AC ratio and particle size of ZVI were also investigated. In addition, from the discussion of synergistic effect between ZVI/AC and MEDL/NaCIO, we found that in the ZVI/AC-MEDL/NaCIO process, ZVI/AC could break the azo bond firstly and then MEDLfNaCIO degraded the aromatic amine products effectively. Reversing the order would reduce the degradation efficiency.展开更多
The luminescent properties of microwave discharge electrodeless mercury lamp（MDEL-Hg） which was ignited within the resonant cavity and photolysis of hydrogen sulfide with low concentration were studied in this paper...The luminescent properties of microwave discharge electrodeless mercury lamp（MDEL-Hg） which was ignited within the resonant cavity and photolysis of hydrogen sulfide with low concentration were studied in this paper.Experiment results indicated that the Interior MDEL-Hg could be made the best of energy utihzation and the efficiency of photolysis of H2S was very significant under the experimental conditions with the initial H2S concentration of 7.9 mg m^-1.With residence time of 1.5 s,the removal efficiency of hydrogen sulfide was 91%,the absolute removal amount（ARA） was 3.24μg s^-1 and the energy consumption was 58.23 mg（kWh）^-1.展开更多
Knowledge of the effective radiation spectrum irradiating substrates from microwave powered electrodeless discharge lamps（MEDLs）, and the active species that directly oxidize substrates in the photolytic process, is...Knowledge of the effective radiation spectrum irradiating substrates from microwave powered electrodeless discharge lamps（MEDLs）, and the active species that directly oxidize substrates in the photolytic process, is fragmentary and unclear. In this work, we conducted a comparative study using MEDLs made with quartz envelopes（MEDL-quartz） and with borosilicate Pyrex envelopes（MEDL-Pyrex） targeting the degradation of Rhodamine B（Rh B）via radical-extinguishing tests. We found that UVC/UVB radiation is essential to generate·OH and H2O2 in the MEDL-quartz system. The degradation of Rh B mostly originates from·OH species, which account for a contribution of 53.8%, while the remaining contribution is attributed to oxidation by H2O2 and direct photolysis. This degradation is influenced by several parameters. Acidic and neutral p Hs, but not extreme alkaline p H, benefit the degradation. To ensure a high intensity of UVC/UVB, the optimum ratio of the MEDL volume to the aqueous solution volume（VL/VS） is 0.4. Concentrations of 0.15-0.20 mmol/L of Rh B are suitable to obtain an effective quantum absorbance in the MEDL-quartz system,showing a high decomposition rate of 5.6 × 10^-3（mmol/L）min-1. Moreover, two other substrates, Reactive Brilliant Red X-3B and Safranine T, were tested and found to be efficiently degraded in the MEDL-quartz system.展开更多
Photodegradation of malachite green (MG) as the model molecule with TiO2 catalyst by microwave discharge electrodeless lamps (MDELs) was investigated.The effects of different parameters in photodegradation of MG,such ...Photodegradation of malachite green (MG) as the model molecule with TiO2 catalyst by microwave discharge electrodeless lamps (MDELs) was investigated.The effects of different parameters in photodegradation of MG,such as MDEL shape,microwave power,initial solution concentration,and catalyst dosage were discussed.Additionally,the photodegradation of congo red,acid black,acid fuchsine and salicylic acid with anatase TiO2 catalyst were investigated under the optimal reaction condition.The results showed that the MDEL is a new treatment method for enhancing photodegradation of organic contaminants with TiO2 catalyst.展开更多
基金supported by the Major Projects on Control and Rectification of Water Body Pollution (Water Special Project) (No.2009ZX07010-001,2008ZX07526-001)the National Basic Research Program (973) of China (No.2008CB418201)
文摘A comparative study of treatment of simulated wastewater containing Reactive Red 195 using zero-valent iron/activated carbon （ZVI/AC）, microwave discharge electrodeless lamp/sodium hypochlorite （MDEL/NaCIO） and the combination of ZVI/AC- MDEL/NaCIO was conducted. The preliminary results showed the two steps method of ZVI/AC-MDEL/NaCIO had much higher degradation efficiency than both single steps. The final color removal percentage was nearly up to 100% and the chemical oxygen demand reduction percentage was up to approximately 82%. The effects of operational parameters, including initial pH value of simulated wastewater, ZVI/AC ratio and particle size of ZVI were also investigated. In addition, from the discussion of synergistic effect between ZVI/AC and MEDL/NaCIO, we found that in the ZVI/AC-MEDL/NaCIO process, ZVI/AC could break the azo bond firstly and then MEDLfNaCIO degraded the aromatic amine products effectively. Reversing the order would reduce the degradation efficiency.
基金supported by the Shanghai Natural Science Foundation(No.07ZR14004)
文摘The luminescent properties of microwave discharge electrodeless mercury lamp（MDEL-Hg） which was ignited within the resonant cavity and photolysis of hydrogen sulfide with low concentration were studied in this paper.Experiment results indicated that the Interior MDEL-Hg could be made the best of energy utihzation and the efficiency of photolysis of H2S was very significant under the experimental conditions with the initial H2S concentration of 7.9 mg m^-1.With residence time of 1.5 s,the removal efficiency of hydrogen sulfide was 91%,the absolute removal amount（ARA） was 3.24μg s^-1 and the energy consumption was 58.23 mg（kWh）^-1.
基金supported by the National Natural Science Foundation of China (No. 5080167)
文摘Knowledge of the effective radiation spectrum irradiating substrates from microwave powered electrodeless discharge lamps（MEDLs）, and the active species that directly oxidize substrates in the photolytic process, is fragmentary and unclear. In this work, we conducted a comparative study using MEDLs made with quartz envelopes（MEDL-quartz） and with borosilicate Pyrex envelopes（MEDL-Pyrex） targeting the degradation of Rhodamine B（Rh B）via radical-extinguishing tests. We found that UVC/UVB radiation is essential to generate·OH and H2O2 in the MEDL-quartz system. The degradation of Rh B mostly originates from·OH species, which account for a contribution of 53.8%, while the remaining contribution is attributed to oxidation by H2O2 and direct photolysis. This degradation is influenced by several parameters. Acidic and neutral p Hs, but not extreme alkaline p H, benefit the degradation. To ensure a high intensity of UVC/UVB, the optimum ratio of the MEDL volume to the aqueous solution volume（VL/VS） is 0.4. Concentrations of 0.15-0.20 mmol/L of Rh B are suitable to obtain an effective quantum absorbance in the MEDL-quartz system,showing a high decomposition rate of 5.6 × 10^-3（mmol/L）min-1. Moreover, two other substrates, Reactive Brilliant Red X-3B and Safranine T, were tested and found to be efficiently degraded in the MEDL-quartz system.
文摘Photodegradation of malachite green (MG) as the model molecule with TiO2 catalyst by microwave discharge electrodeless lamps (MDELs) was investigated.The effects of different parameters in photodegradation of MG,such as MDEL shape,microwave power,initial solution concentration,and catalyst dosage were discussed.Additionally,the photodegradation of congo red,acid black,acid fuchsine and salicylic acid with anatase TiO2 catalyst were investigated under the optimal reaction condition.The results showed that the MDEL is a new treatment method for enhancing photodegradation of organic contaminants with TiO2 catalyst.
