EDTA对微电解体系降解对硝基酚的影响

考察了EDTA对微电解体系降解对硝基酚的影响及作用机制,结果表明,EDTA能够提高微电解处理对硝基酚的效果;单因素试验法确定了微电解/EDTA体系处理1000mg·l~(-1)对硝基酚的最佳条件:铁屑量120g·l~(-1),碳量20g·l~(-1),pH值为3,EDTA浓度1mmol·l~(-1).在此条件反应60min,对硝基酚去除率为89.7%,而常规微电解在最佳条件下对硝基酚的去除率仅为53.8%.值得关注的是EDTA不仅提高了对硝基酚的去除率,而且拓宽了微电解体系对pH值的适应范围,在中性条件下微电解/EDTA体系对硝基酚的去除率达到了63.5%,而相同条件下传统微电解法仅为19.5%.同时,通过对降解产物的鉴定,分析了对硝基酚在微电解/EDTA体系的降解途径.

THE EFFECT OF EDTA ON THE DEGRADATION OF 4-NITROPHENOL IN MICRO-ELECTROLYSIS SYSTEM

The main disadvantage of conventional micro-electrolysis treatment is that the degradation efficiency is not very high. To solve this problem, the effect of EDTA enhancement on the degradation of 4-NP in the micro-electrolysis/EDTA system was investigated, during which EDTA and 4-NP was degraded by the micro-electrolysis system. The results showed that EDTA could improve the removal rate of 4-NP. The operating conditions for degradation of 4-NP (1000 mg·l~(-1)) in the micro-electrolysis/EDTA system were optimized by individual factor experiments and they were as following: C(Fe) =120 g ·~(-1), C(C) =20 g·l~(-1), C(EDTA) =1 mmol · l~(-1), pH =3. Under this condition, 4-NP removal rates reached 89.7% within 60 min, while the removal rate of 4-NP was only achieved 53.8% by the convention micro-electrolysis treatment. The most deserves attention was that micro-electrolysis/EDTA system also displayed a reasonable good degradation activity in a neutral condition. The removal of 4-NP in micro-electrolysis/EDTA system was over 63.5% at pH of 7, while it was only 19. 5% in micro-electrolysis system. The degradation products of 4-NP were identified with GC/MS methods and the degradation pathways of 4-NP were discussed.