碱度和浊度对混凝去除磺胺甲唑与土霉素的影响

为研究不同碱度和浊度下抗生素SMZ(磺胺甲唑)和OTC(土霉素)的混凝去除特征,选择PAC(聚合氯化铝)为混凝剂,并分别以碳酸氢钠、高岭土调节碱度〔以ρ(CaCO₃)计〕和浊度进行混凝模拟试验. 结果表明:当浊度为10 NTU时,SMZ和OTC的混凝去除率随着c(PAC)(以Al3+计)的增加而增加；在碱度为100 mg/L、c(PAC)为0.35×10-3 mol/L时,浊度对抗生素的去除有一定的影响但不显著,对SMZ去除的影响大于OTC. c(PAC)为0 mol/L时,高岭土对目标抗生素的吸附去除率较低,表明对抗生素去除起主要作用的是PAC. 碱度对SMZ和OTC的混凝去除率影响显著,这种影响是通过同时影响PAC的水解产物形态和抗生素总电荷而发挥作用的. 碱度为0 mg/L时,SMZ与OTC的混凝去除率分别为6.79%、-3.42%；碱度为25、100 mg/L时,SMZ与OTC的混凝去除率明显增加,并且当c(PAC)<0.3×10-3 mol/L时,低碱度(25 mg/L)下抗生素的混凝去除率优于高碱度(100 mg/L),而当c(PAC)>0.3×10-3 mol/L时则相反. 研究显示,碱度和浊度对混凝去除抗生素均有明显影响,但碱度对混凝去除抗生素的影响大于浊度. 

Effects of Alkalinity and Turbidity on SMZ and OTC Removal by Coagulation

The effects of alkalinity and turbidity on SMZ and OTC removal by coagulation were studied with commercial PAC as the coagulant, and sodium bicarbonate and kaolin were used to adjust the alkalinity and turbidity. The results showed that the SMZ and OTC removal were increased with the increase of PAC concentration when the turbidity was 10 NTU. When alkalinity was 100 mg/L and c(PAC) was 0.35×10-3 mol/L, turbidity had certain influence, but was not particularly significant for SMZ and OTC removal. The impact on SMZ was greater than OTC. When c(PAC) was 0 mol/L, the adsorption rates of SMZ and OTC were obviously lowered by kaolin, which showed that PAC played an important role in SMZ and OTC removal. Moreover, alkalinity remarkably affected SMZ and OTC removal, and the effect simultaneously played an important role on the PAC hydrolysis and antibiotics total charge. The SMZ and OTC removals were 6.79%,-3.42%. Meanwhile, the alkalinity was 0 mg/L. The SMZ and OTC removals significantly increased when alkalinity was 25 mg/L and 100 mg/L. SMZ and OTC removals under low alkalinity (25 mg/L) were better than those under high alkalinity (100 mg/L) in c(PAC)<0.3×10-3 mol/L, while the removals under high alkalinity were better than those under low alkalinity in c(PAC)>0.3×10-3 mol/L. In conclusion, alkalinity and turbidity impacted antibiotics removal by the process of coagulation, but the effect of alkalinity on antibiotics removal was greater than turbidity.