共查询到4条相似文献,搜索用时 0 毫秒
1.
Xiang ZHANG Xiaogang GU Shuguang LU Zhouwei MIAO Minhui XU Xiaori FU Muhammad DANISH Mark L. BRUSSEAU Zhaofu QIU Qian SUI 《Frontiers of Environmental Science & Engineering》2016,10(3):502-512
Trichloroethene (TCE) degradation by Fe(III)-activated calcium peroxide (CP) in the presence of citric acid (CA) in aqueous solution was investigated. The results demonstrated that the presence of CA enhanced TCE degradation significantly by increasing the concentration of soluble Fe(III) and promoting H2O2 generation. The generation of HO? and O2-? in both the CP/Fe(III) and CP/Fe(III)/CA systems was confirmed with chemical probes. The results of radical scavenging tests showed that TCE degradation was due predominantly to direct oxidation by HO?, while O2-? strengthened the generation of HO? by promoting Fe(III) transformation in the CP/Fe(III)/CA system. Acidic pH conditions were favorable for TCE degradation, and the TCE degradation rate decreased with increasing pH. The presence of Cl-, HCO3-, and humic acid (HA) inhibited TCE degradation to different extents for the CP/Fe(III)/CA system. Analysis of Cl- production suggested that TCE degradation in the CP/Fe(III)/CA system occurred through a dechlorination process. In summary, this study provided detailed information for the application of CA-enhanced Fe(III)-activated calcium peroxide for treating TCE contaminated groundwater. 相似文献
2.
Minhui XU Xiaogang GU Shuguang LU Zhouwei MIAO Xueke ZANG Xiaoliang WU Zhaofu QIU Qian SUI 《Frontiers of Environmental Science & Engineering》2016,10(3):438-446
The thermally activated persulfate (PS) degradation of carbon tetrachloride (CT) in the presence of formic acid (FA) was investigated. The results indicated that CT degradation followed a zero order kinetic model, and CO 2 – · was responsible for the degradation of CT confirmed by radical scavenger tests. CT degradation rate increased with increasing PS or FA dosage, and the initial CT had no effect on CT degradation rate. However, the initial solution pH had effect on the degradation of CT, and the best CT degradation occurred at initial pH 6. Cl– had a negative effect on CT degradation, and high concentration of Cl– displayed much strong inhibition. Ten mmol·L–1HCO 3 – promoted CT degradation, while 100 mmol·L–1NO 3 – inhibited the degradation of CT, but SO 4 2– promoted CT degradation in the presence of FA. The measured Cl–concentration released into solution along with CT degradation was 75.8% of the total theoretical dechlorination yield, but no chlorinated intermediates were detected. The split of C-Cl was proposed as the possible reaction pathways in CT degradation. In conclusion, this study strongly demonstrated that the thermally activated PS system in the presence of FA is a promising technique in in situ chemical oxidation (ISCO) remediation for CT contaminated site. 相似文献
3.
Wenchao Jiang Ping Tang Shuguang Lu Xiang Zhang Zhaofu Qiu Qian Sui 《Frontiers of Environmental Science & Engineering》2018,12(2):6
4.
Salima Chergui Ahmed Réda Yeddou Abdelmalek Chergui Farid Halet Hamza Amaouche Boubekeur Nadjemi 《毒物与环境化学》2015,97(10):1289-1295
This work is dedicated to the removal of free cyanide from aqueous solution by oxidation with hydrogen peroxide H2O2 catalyzed by neutral activated alumina. Effects of initial molar ratio [H2O2]0/[CN?]0, catalyst amount, pH, and temperature on cyanide removal have been examined. The presence of activated alumina has increased the reaction rate showing thus, a catalytic activity. The rate of removal of cyanides increases with rising initial molar ratio [H2O2]0/[CN?]0 but decreases at pH 10 to 12. Increasing the alumina amount from 1.0 to 30 g/L has a beneficial effect, and increasing the temperature from 20 °C to 35 °C improves cyanide removal. The kinetics of cyanide removal has been found to be of pseudo-first-order with respect to cyanide and the rate constants have been determined. 相似文献