微波辅助Cu(Ⅱ)-Fenton体系催化氧化处理对硝基苯酚废水

Treatment of PNP wastewater by microwave assisted Cu(Ⅱ)-Fenton catalytic oxidation process

为了拓宽Fenton反应pH范围,提高降解效率、减少药剂用量,向Fenton体系中添加辅助催化剂Cu(Ⅱ),并对微波辅助催化氧化对硝基苯酚(PNP)模拟废水工艺进行了研究。提出微波辐照-放置处理工艺,并与普通全过程微波处理工艺进行了比较。结果表明,该体系处理工艺将Fenton反应最佳pH范围由2.0~3.5拓宽到2.0~5.5;在pH=5.0时,对于100 mg/L的PNP溶液,当[Cu2+]=0.8 mg/L、[Fe2+]=3.0 mg/L、[H2O2]=0.2 g/L,微波功率250 W,辐照2.0 min、放置4.0 min,PNP去除率可达98%以上;辅助催化剂Cu2+的加入增强了氧化效果,同时节约药品20%以上。通过对比实验发现,Cu2+与Fe2+发生了某种作用机制,联合促进了体系中·OH的生成。该反应体系不仅将传统Fenton反应体系狭窄的pH值范围延伸到接近中性的区域5.0~5.5,又可在短时间内使PNP去除率达到98%以上。

This study investigated the removal of p-nitrophenol(PNP) in the simulated wastewater by microwave catalytic oxidation process,where Cu(Ⅱ) was introduced into Fenton system as an assistant catalyst. Microwave 'irradiation-standing'process was presented and compared with traditional microwave process. Results indicate the optimal range of pH in Fenton reaction was extended from 2. 0 ~ 3. 5 to 2. 0 ~ 5. 5. Under the conditions of pH = 5. 0,[Cu2 +]=0. 8 mg/L,[Fe2 +]=3. 0 mg/L,[H2O2]=0. 2 g/L,over 98% of PNP was removed in 100 mg/L wastewater with the microwave power of 250 W,irradiation time of 2. 0 min and standing time of 4. 0 min. The introduction of Cu2 +enhanced the PNP degradation efficiency and saved over 20% of Fe2 + and H2O2consumption. In the comparative experiments,·OH generation was strengthened by the cooperation of Cu2 +and Fe2 +. This effect is probably controlled by some concealed mechanism. Overall,the presented process not only extents narrow pH range of traditional Fenton reaction to a nearly neutral condition but also yields a dramatically high removal efficiency in a short time.