Environmental Science and Pollution Research - Drinking water containing environmental endocrine disruptor compounds (EDCs) endangers human health, and researching the purification process of... 相似文献
Copper ions were first adsorbed by zeolite 4A synthesized from bauxite tailings, the desorption of Cu(II) using Na2EDTA solutions was performed, and the recycling of zeolite 4A in adsorption and desorption was systematically investigated. It was observed that the Cu(II) removal efficiency was directly dependent on the initial pH value. The maximum removal efficiency of Cu(II) was 96.2% with zeolite 4A when the initial pH value was 5.0. Cu(II) was completely absorbed in the first 30 min. It was also observed that the desorption efficiency and zeolite recovery were highly dependent on the initial pH and concentration of Na2EDTA in the solution. The desorption efficiency and percent of zeolite recovered were 73.6 and 85.9%, respectively, when the Na2EDTA solution concentration was 0.05 mol L?1 and the pH value was 8. The recovered zeolites were pure single phase and highly crystalline. After 3 cycles, the removal efficiency of Cu(II) was as high as 78.9%, and the zeolite recovery was 46.9%, indicating that the recovered zeolites have good adsorption capacity and can repeatedly absorb Cu(II).
Photochemical degradation of fluoroquinolone ciprofloxacin (CIP) in water by UV and UV/H2O2 were investigated. The degradation rate of CIP was affected by pH, H2O2 dosage, as well as the presence of other inorganic components. The optimized pH value and H2O2 concentration were 7.0 and 5 mM. Carbonate and nitrate both impeded CIP degradation. According to liquid chromatography–tandem mass spectrometry analysis, four and 16 products were identified in UV and UV/H2O2 system, respectively. Proposed degradation pathways suggest that reactions including the piperazinyl substituent, quinolone moiety, and cyclopropyl group lead to the photochemical degradation of CIP. Toxicity of products assessed by Vibrio qinghaiensis demonstrated that UV/H2O2 process was more capable on controlling the toxicity of intermediates in CIP degradation than UV process. 相似文献