A gas-phase surface discharge(GSD)was employed to optimize the discharge reactor structure and investigate the dye degradation.A dye mixture of methylene blue,acid orange and methyl orange was used as a model pollut...A gas-phase surface discharge(GSD)was employed to optimize the discharge reactor structure and investigate the dye degradation.A dye mixture of methylene blue,acid orange and methyl orange was used as a model pollutant.The results indicated that the reactor structure of the GSD system with the ratio of tube inner surface area and volume of 2.48,screw pitch between a high-voltage electrode of 9.7 mm,high-voltage electrode wire diameter of 0.8 mm,dielectric tube thickness of2.0 mm and tube inner diameter of 16.13 mm presented a better ozone(O_3)generation efficiency.Furthermore,a larger screw pitch and smaller wire diameter enhanced the O_3generation.After the dye mixture degradation by the optimized GSD system,73.21%and 50.74%of the chemical oxygen demand(COD)and total organic carbon removal rate were achieved within 20 min,respectively,and the biochemical oxygen demand(BOD)and biodegradability(BOD/COD)improved.展开更多
Processes based on non-thermal plasma(NTP) for indoor air treatment inevitably lead to the formation of toxic by-products such as ozone(O3) and nitrogen oxides(NOx). Adding a step of heterogeneous catalysis in s...Processes based on non-thermal plasma(NTP) for indoor air treatment inevitably lead to the formation of toxic by-products such as ozone(O3) and nitrogen oxides(NOx). Adding a step of heterogeneous catalysis in series with NTP could allow for the decomposition of the by-products. Therefore, different catalysts were developed based on transition metal oxides, such as NiOx, CoOxand MnOxwith different weight percentage 1, 5 and 10 wt.%,deposited on a γ-Al2O3 support. The O3 removal efficiency(ORE) and the NOxremoval efficiency(NRE) were very encouraging in dry air: about 65% and 80%, respectively, by using2 g 5 wt.% MnOx/Al2O3 catalyst under the experimental conditions. However, strongly negative effects of relative humidity(RH) on the catalytic decomposition performance were observed. To overcome this limitation, the catalyst surface was modified to make it hydrophobic using a cost-effective chemical grafting method. This treatment consisted in impregnating the 5 wt.% MnOx/Al2O3 catalyst with different trichloro(alkyl)silanes(TCAS).The effects of different linker lengths and amounts of TCAS for the hydrophobicity and the decomposition performance of surface-modified catalysts under humid conditions were investigated. Our results show that the surface-modified catalyst with the shortest linker and 0.25 mmol/gcatof modifying agent represents the best catalytic decomposition performance for O3. Its ORE is 41% at 60% RH, which is twice that of the non-modified catalyst.展开更多
基金National Natural Science Foundation of China(No.51477025)
文摘A gas-phase surface discharge(GSD)was employed to optimize the discharge reactor structure and investigate the dye degradation.A dye mixture of methylene blue,acid orange and methyl orange was used as a model pollutant.The results indicated that the reactor structure of the GSD system with the ratio of tube inner surface area and volume of 2.48,screw pitch between a high-voltage electrode of 9.7 mm,high-voltage electrode wire diameter of 0.8 mm,dielectric tube thickness of2.0 mm and tube inner diameter of 16.13 mm presented a better ozone(O_3)generation efficiency.Furthermore,a larger screw pitch and smaller wire diameter enhanced the O_3generation.After the dye mixture degradation by the optimized GSD system,73.21%and 50.74%of the chemical oxygen demand(COD)and total organic carbon removal rate were achieved within 20 min,respectively,and the biochemical oxygen demand(BOD)and biodegradability(BOD/COD)improved.
基金financially supported by French Ministry of Higher Education and Research (No. 2015/386)
文摘Processes based on non-thermal plasma(NTP) for indoor air treatment inevitably lead to the formation of toxic by-products such as ozone(O3) and nitrogen oxides(NOx). Adding a step of heterogeneous catalysis in series with NTP could allow for the decomposition of the by-products. Therefore, different catalysts were developed based on transition metal oxides, such as NiOx, CoOxand MnOxwith different weight percentage 1, 5 and 10 wt.%,deposited on a γ-Al2O3 support. The O3 removal efficiency(ORE) and the NOxremoval efficiency(NRE) were very encouraging in dry air: about 65% and 80%, respectively, by using2 g 5 wt.% MnOx/Al2O3 catalyst under the experimental conditions. However, strongly negative effects of relative humidity(RH) on the catalytic decomposition performance were observed. To overcome this limitation, the catalyst surface was modified to make it hydrophobic using a cost-effective chemical grafting method. This treatment consisted in impregnating the 5 wt.% MnOx/Al2O3 catalyst with different trichloro(alkyl)silanes(TCAS).The effects of different linker lengths and amounts of TCAS for the hydrophobicity and the decomposition performance of surface-modified catalysts under humid conditions were investigated. Our results show that the surface-modified catalyst with the shortest linker and 0.25 mmol/gcatof modifying agent represents the best catalytic decomposition performance for O3. Its ORE is 41% at 60% RH, which is twice that of the non-modified catalyst.