UV/NaClO高级氧化法降解再生水中磺胺甲恶唑

Degradation of sulfamethoxazole in reclaimed water by UV/NaClO advanced oxidation process

为了提高再生水水质,采用UV/NaClO高级氧化法降解水中的磺胺甲恶唑(SMX),对比各种降解方法对SMX的去除效果,研究影响UV/NaClO降解SMX的因素,考察消毒副产物三氯甲烷(CHCl_3)的产生情况,研究SMX在实际再生水中的去除效果.研究表明,UV/NaClO降解SMX的速率常数是单独UV、单独NaClO、UV/H_2O_23种处理方法的3.9、60、2.5倍,降解的最佳pH为3～8;NaClO投量会影响去除效果,在SMX初始浓度为1μmol/L,pH为7.4的条件下,最佳投量为0.1 mmol/L;污水厂二级出水和水环境中普遍存在的腐殖酸会与SMX竞争活性自由基和光子,降低了SMX去除率;与单独NaClO处理相比,利用UV/NaClO工艺能够明显减少水中三氯甲烷的产生;SMX在实验室超滤机过滤后的自来水中的降解速率是在实际再生水中的6.8倍.

The UV/NaClO advanced oxidation process was applied to degrade sulfamethoxazole (SMX) in order to improve reclaimed water quality. The effects of various degradation processes on SMX removal were compared. The factors influencing the decay of SMX by UV/NaClO process and the formation of disinfection by-products trichloromethane (CHCl3) were analyzed. The performance of the UV/NaClO process for degrading SMX in real reclaimed water was analyzed. Results show that the degradation rate constants of SMX in UV/NaClO process was respectively 3.9, 60 and 2.5 times faster than the method of UV, chlorination alone and UV/H2O2 and the degradation conducted better at pH 3~8. The rate of SMX degradation peaked at oxidant dosage of 0.1 mmol/L at the conditions of 1μmol/L SMX and pH 7.4. Humic acid (HA) prevailing in secondary effluent of wastewater treatment plant and water environment decreased the SMX degradation by competing photons and active radicals with target contaminant. The less formation of trichloromethane was observed in UV/NaClO process compared with chlorination alone. The degradation rates observed in laboratory level was 6.8 times than that in real reclaimed water.