摘要
采用Fenton法处理高浓度腐殖酸模拟废水,考察反应时间、初始pH、H2O2和Fe2+投量对腐殖酸COD、TOC、UV254、A400的影响,通过体系平均氧化态(η)、A465/A665、氧化/混凝作用去除COD比值(φ)、Zeta电位(ζ)等的变化研究氧化和混凝作用对腐殖酸去除的特性.结果表明,Fenton试剂能在较宽初始pH范围(2.0～5.0)内有效降解腐殖酸.当反应时间为2h,腐殖酸A400降低值(78.2%～94.5%)比UV254(75.6%～88.4%)高,COD去除率(50.8%～62.5%)比TOC(31.2%～35.1%)高.腐殖酸的去除由氧化作用(CODoxid)和混凝作用(CODcoag)共同完成.反应初始阶段腐殖酸主要通过氧化作用迅速降解去除.腐殖酸易被部分氧化为小分子有机物而不易矿化,过多Fe2+投量([Fe2+]>0.08mol/L)会使CODoxid下降.混凝主要通过电中和及吸附网捕作用进行,氧化作用影响混凝作用,高CODoxid导致低CODcoag;高H2O2投量下([H2O2]>0.2mol/L)Fe2+投量显著影响混凝作用对COD的去除.
Simulated high concentration humic acids （HA） wastewater was treated by Fenton process. The influence of reaction time,initial pH,H2 O2 and Fe^2 ＋ dosage on the reduction results of COD,TOC,UV254 ,A400 are presented. The changes of mean oxidation state （η）,A465 /A665 ,the ratio of COD removal by oxidation to that by coagulation （φ） and Zeta potential （ζ） were used to evaluate the roles of oxidation and coagulation in reducing HA during Fenton treatment. The results demonstrate that Fenton＇s reagent can effectively degrade HA under a wide initial pH range （2. 0-5. 0）,simultaneously the absorbance decrease in 400 nm was higher （from 78. 2 % to 94. 5 % ） than that in 254 nm （from 75. 6 % to 88. 4 % ） and the COD removal （from 50. 8 % to 62. 5 % ） is higher than TOC removal （from 31. 2 % to 35. 1 % ） in 2 h reaction time. The amount of HA is removed by both oxidation and coagulation. Oxidation played a primary role in removal of HA at the beginning of Fenton reaction. The large molecular weight component of HA appears to be easily degraded and the formations of low molecular persistent organic intermediate compounds are difficult to be mineralized. The COD removal efficiency by oxidation decreases over the ferrous dosage of 0. 08 mol /L. Furthermore,the results reveal that HA removal by coagulation was reduced mainly by charge neutralization as well as adsorption bridge building. Results highlight the role of oxidation in controlling the efficiency of COD removal by coagulation,so high CODoxid may cause relatively low CODcoag. Meanwhile,ferrous dosage greatly influences COD removal by coagulation at high peroxide dosages over 0. 2 mol /L.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2010年第4期996-1001,共6页
Environmental Science
基金
"十一五"国家科技支撑计划项目(2008BAE64B05)
广州市重大科技项目(2008DLB2080500)
关键词
腐殖酸
FENTON
氧化
混凝
humic acids（HA）
Fenton
oxidation
coagulation
