针对已经达标的焦化废水中存在的残余有机物,考察O3/H2O2氧化工艺的有效性并期望实现工业循环水水质目标的工艺条件。以实际达标排放的焦化废水水样作为研究对象,在自行设计的圆柱形鼓泡反应器中建立了O3与H2O2协同氧化反应体系,通过试验明确了O3浓度、H2O2投加量、溶液pH值、自由基抑制剂等因素对有机物降解的影响规律。结果表明:在水温为25℃时、水样pH值为7.0、臭氧浓度为11.01mg/L、H2O2浓度为1.0mmol/L的条件下,反应30min后O3/H2O2氧化工艺对COD和UV254的去除率分别达到78.1%和83.7%,相比单独O3氧化分别提高了14.3%和4.1%,达到了良好的处理效果。pH值的变化及TBA的添加能很大程度地影响着·OH的生成从而影响氧化反应的进行,表明了复杂组分共存的废水其氧化反应顺序由有机物的不饱和性及氧化剂的氧化还原电位决定。
The coking wastewater which meets the discharge standard still contains a small quantity of organic compounds. A self-made cylindrical bubbling reactor was established by coupling the O3/H2O2 oxidation process was used to remove these residual compounds to realize industrial water reuse cycle. The effects of O3 concentration, H2O2 dosage, pH and free radical inhibitor were investigated. The results showed that when the environmental temperature, pH, O3 concentration and H2O2 dosage were 25℃, 7.0, 11.01 mg/L and 1.0 mmol/L respectively, the removal ratios of COD and UV254 were 78.1% and 83.7% for O3/H2O2 oxidation process, whereas the removal ratios were just 63.8% and 79.6% for O3 alone. The reaction process was affected by the acidity significantly. Tribenzyl amine (TBA) was added in the reaction liquid as a·OH free radical inhibitor to confirm the oxidation mechanism. The aromatics removal was approximate during the first 15 min for the system with and without TBA. This result indicated that O3 was the dominating oxidant. 4 g/L TBA could inhibit the production of · OH which meant nearly 20% oxidation was accomplished by .OH. It was concluded that the complex components contained in the wastewater were oxidized according to the unsaturation of organic compounds and the redox potential of the oxidants.