Fenton试剂氧化对硝基酚中氧化还原电位的变化规律

摘要

Degradation of p-nitrophenol (PNP) in aqueous medium by Fenton reagent was conducted to monitor the variation of oxidation-reduction potential (ORP) during Fenton oxidation process. Results showed that under the condition of initial pH value was 3, H2 O2 dosage was 3 mmol/L and Fe2+ dosage was 0.3 mmol/L, PNP could decreased to 5 mg/L in 5.0 min, giving the removal rate of 95％. The biodegradability of wastewater was greatly improved for the BOD5/COD value increased from 0.073 to 0. 390. ORP could reflect the oxidative redox status of Fenton system perfectly; Fe2+, · OH, H2O2, Fe3+ and hydroquinone were main oxidation-reduction materials, but which one could be reflect by ORP need further verification. ORP was distinctly corresponded with Fe2+/Fe3+ , it was also found to be an effective indicator to monitor the beginning, quick reaction and ending of p-nitrophenol degradation by Fenton oxidation process.%考察了Fenton试剂氧化对硝基苯酚(PNP)过程中氧化还原电位(ORP)的变化规律.结果表明:(1)当pH为3、H2O2投加量为3 mmol/L、Fe2+投加量为0.3 mmol/L时,废水中PNP在5.0 min时降到5 mg/L左右,去除率达95%;废水可生化性得到有效改善(BOD5/COD由最初的0.073升至0.390).(2)ORP反应了整个Fenton体系中的氧化还原状态,而整个体系中主要的氧化还原物质是Fe2+、·OH、H2O2、0Fe3+以及氢醌等,ORP变化规律直接反映了哪种氧化还原物质的变化尚未明确,需进一步验证.(3)ORP的变化直接反映了Fe2+/Fe3+的形态变化.(4)利用ORP的变化可以反映Fenton试剂降解有机物的起始、快速降解及降解结束的稳定阶段.