Fe0 Al0/O2体系氧化处理乙二胺四乙酸水溶液的性能

Oxidative Treatment of Ethylene Diamine Tetra Acetic Acid Aqueous Solution by Bimetallic Fe0 Al0/O2 System

摘要:

研发了常温常压下由O2自发还原而产生H2O2和·OH等活性氧（ROS）的Fe0 Al0/O2绿色高级氧化工艺，以乙二胺四乙酸（EDTA）模拟废水为研究对象，考察了溶液的初始pH值、铝铁的质量比、EDTA的初始浓度等因素对EDTA降解的影响.采用N,N 二乙基对苯二胺 辣根过氧化物酶（DPD POD）法、苯甲酸捕捉法、氧气吹脱、溶液总有机碳（TOC）的变化以及EDTA的降解产物等证实了H2O2和·OH的原位产生及EDTA的氧化降解机制.结果表明：Fe0 Al0/O2体系对EDTA的去除率随溶液初始pH的升高而降低，但在pH=3～9范围内，始终具有较好的EDTA去除率；随Al0∶Fe0质量比增加以及EDTA初始浓度降低，EDTA的去除率增大；在初始pH=9、EDTA初始浓度为0.5 mmol·L-1、铝铁的质量比为1∶1的条件下反应3 h之后EDTA的去除率达到了90%以上；EDTA主要通过·OH的高级氧化去除，其中间产物为亚氨基二乙酸、甲酸和乙酸，最终被矿化降解为CO2和H2O，3 h内TOC去除率达到72.5%.研究表明：Fe0 Al0/O2体系处理EDTA水溶液，无需外加H2O2，此体系节省运行操作费用，且适用pH范围广.

Abstract:

Fe0 Al0/O2 green advanced oxidation process in which reactive oxygen species (ROS) of H2O2 and ·OH is generated by the O2 spontaneous reduction at normal temperature and pressure was developed. Ethylene diamine tetra acetic acid (EDTA) simulated wastewater as the research object, effects including the initial pH, the mass ratio of Fe0 and Al0 and the initial EDTA concentration were investigated. The in situ generation of H2O2 and ·OH, as well as the oxidative degradation mechanism of EDTA degradation were confirmed by the determine methods of N,N diethyl p phenylene diamine horseradish peroxidase（DPD POD）, benzoic capturing, oxygen stripping, total oxygen carbon (TOC) changes and EDTA degradation products. The results show that EDTA degradation efficiency by the Fe0 Al0/O2 system decreases with the initial pH increasing, but it is still high at the pH range of 3~9. With the mass ratio of Al0 and Fe0 increasing and the initial concentration of EDTA reducing the removal rate of EDTA increases. Under the conditions that the initial pH is 9, initial EDTA concentration is 0.5 mmol·L-1 and mass ratio of Fe0∶Al0 is 1∶1, the EDTA removal efficiency reached at 90% above. EDTA is removed mainly through advanced oxidation. The intermediates include iminodiacetic acid, formic acid and acetic acid which are eventually mineralized to CO2 and H2O. The TOC removal efficiency reaches 72.5% after 3 h. The studies indicate that Fe0 Al0/O2 system for the EDTA degradation shows many advantages, such as no external H2O2 adding, running cost saving and wide range of pH for application.