基于不同自由基的高级氧化技术对水中诺氟沙星的去除效果

Removal performance of norfloxacin from waters by advanced oxidation processes based on different free radicals

抗生素在水中的赋存浓度较低,难以被常规的城市污水处理系统有效去除。考察了紫外光联合氯(UV/氯)、双氧水(UV/H2O2)、过硫酸盐(UV/PS)3种高级氧化体系对诺氟沙星(NFX)的去除效果。结果表明:UV/氯体系降解NFX相比于其他2种具有显著的高效性,当溶液初始pH为7、氯浓度为30μmol/L时,NFX在2 min内的去除率可达98.67%,相同氧化剂浓度下,UV/H2O2和UV/PS体系10 min内对NFX的去除率仅为41.41%和65.73%;对于UV/氯体系,NFX的去除率随氯浓度的升高而上升,同时考虑成本,最优氯浓度为30μmol/L;pH影响3种体系对NFX的去除速率,但效果不同,对于UV/氯体系,强碱性条件有利于NFX的去除,对于UV/H2O2和UV/PS体系,中性及弱碱性更有利于NFX的去除;水体基质Cl-对UV/氯体系去除NFX有抑制作用,但对UV/H2O2和UV/PS体系影响不大;HCO3^-对3种体系去除NFX均有抑制作用。

Because of their low occurrence concentration in water,the antibiotics are difficult to be effectively removed by the conventional municipal sewage treatment system.The removal efficiency of norfloxacin(NFX)by ultraviolet combined chlorine(UV/chlorine),hydrogen peroxide(UV/H2O2)and persulfate(UV/PS)was investigated.The results showed that the degradation of NFX by UV/chlorine was significantly more efficient than the other two systems.When the initial pH of solution was 7 and the concentration of chlorine was 30μmol/L,the removal rate of NFX in 2 min could reach 98.67%.At the same oxidant concentration,the removal rate of NFX was 41.41%and 65.73%after 10 min by UV/H2O2 and UV/PS,respectively.For UV/chlorine system,the removal rate of NFX increased with the increase of chlorine concentration with the optimal concentration being 30μmol/L.The pH had different effects on the removal rate of NFX by three systems.For UV/chlorine system,strong alkaline condition was beneficial for the removal of NFX,while neutral and weak alkalinity was more favorable for the removal of NFX for UV/H2O2 and UV/PS.Cl-in water matrix inhibited the removal of NFX by UV/chlorine,but had little effect on UV/H2O2 and UV/PS,while HCO-3inhibited the removal of NFX by all three systems.