Preparation,characterization and catalytic behavior of hierachically porous CuO/α-Fe_2O_3/SiO_2 composite material for CO and o-DCB oxidation

Hierachically porous （HP） CuO/α-Fe2O3/SiO2 composite material was fabricated by sol-gel method and multi-hydrothermal processes using HP-SiO2 as support.The resulting material was characterized by N2 adsorption-desorption,X-ray diffraction and scanning electron microscopy.The as-prepared CuO/Fe2O3/HP-SiO2 sample,with α-Fe2O3 and CuO nanocrystals,possessed a co-continuous skeleton,through-macroporous and mesoporous structure.Its catalytic behavior for CO and o-DCB oxidation was investigated.The result showed that CuO/Fe2O3/HP-SiO2 catalyst exhibited high catalytic activity for both CO and o-DCB oxidation,indicating its potential application in combined abatement of CO and chlorinated volatile organic compounds.

Catalytic Dechlorination and Kinetics of o-Dichlorobenzene by Pd/Fe

o-Dichlorobenzene (o-DCB) was dechlorinated by Pd/Fe powder in water through catalytic reduction. The dechlorination reaction is believed to take place on the surface site of the catalyst via a pseudo-first-order reaction. The final reduction product of o-DCB is benzene. The dechlorination rate increases with the increase of bulk loading of palladium due to the increase of both the surface loading of palladium and the total surface area. Dechlorination efficiency accounts for 90% at Pd/Fe mass ratio 0.02% and metal to solution ratio about 53.3 g·L^-1 in 120 minutes. Dechlorination is affected by the reaction temperature, pH, Pd/Fe ratio and the addition of Pd/Fe. Ea is found to be 102.5kJ·mol^-1 in the temperature range of 287--313K.

Degradation of o-dichlorobenzene by DBD-NTP co-modified titanium gel catalyst

In order to study the degradation process of dioxins in industrial flue gas,the decomposition of o-dichlorobenzene(o-DCB)in a DBD plasma catalytic reactor was investigated.The results showed that an NTP-catalyzed system,especially using the Cu Mn Ti Oxcatalyst,had better o-DCB degradation performance compared to plasma alone.The combination of the Cu Mn Ti Oxcatalyst with NTP can achieve a degradation efficiency of up to 97.2%for o-DCB;the selectivity of CO and CO_(2)and the carbon balance were 40%,45%,and 85%,respectively.The dielectric constant and electrical property results indicated that the surface discharge capacity of the catalysts played a major role in the degradation of o-DCB,and a higher dielectric constant could suppress the plasma expansion and enhance the duration of the plasma discharge per discharge cycle.According to the O1s XPS and O_(2)-TPD results,the conversion of CO to CO_(2)follows the M-v-K mechanism;thus,the active species on the catalyst surface play an important role.Moreover,the Cu Mn Ti Oxand NTP mixed system exhibited excellent stability,which is probably because Cu doping improved the lifetime of the catalyst.This work can provide an experimental and theoretical basis for research in the degradation of o-DCB by plasma catalyst systems.

水平潜流人工湿地处理邻二氯苯废水研究

采用水平潜流人工湿地(SFCW)处理邻二氯苯(o-DCB)废水,构建了基质分别为壤土、细沙和粗砂的3套芦苇湿地中试系统W-L、W-F、W-C和无植物的壤土湿地对照组W-Z.结果表明,最佳水力停留时间为5 d,最适表面负荷率为150mg.(m2.d)-1,湿地组W-L、W-F、W-C和W-Z对o-DCB的去除率分别为81.2%、71.1%、72.4%和65.2%;8月中旬湿地运行效果最好,进入10月后性能有所下降,各个湿地系统对o-DCB废水处理效果顺序为W-L>W-C>W-Z>W-F,壤土和粗砂基质具有各自的优势;o-DCB浓度和溶解氧(DO)在湿地W-L和W-Z空间分布状况表明DO有利于o-DCB降解;o-DCB残留量在各层土壤中沿水流方向递减,随深度加深而增加;在芦苇组织中呈阶梯状分布,根、茎、叶中平均残留值分别为30.28、14.85和6.18μg.g-1.