臭氧催化氧化处理焦化废水尾水的催化剂适配研究

Catalyst adaptation of tail water of coking wastewater by ozone catalytic oxidation

为解决焦化废水尾水中有机物难降解问题,采用浸渍-煅烧法制备了负载活性金属氧化物的活性氧化铝型催化剂,通过臭氧催化氧化实验探索了载体和活性组分种类对COD去除率的影响,并对去除效率最高效的催化剂进行了表征分析。结果表明:BET分析发现Mn-Ni/γ-Al_(2)O_(3)(n_(Mn)∶n_(Ni)=2∶1)保留了γ-Al_(2)O_(3)的介孔结构,具有较大的表面积和孔体积,但负载后催化剂的比表面积和孔体积都有所降低,孔径变大;XPS和XRD分析发现锰主要以α-MnO_(2)形式存在,镍主要以复合价态存在,且二者存在强烈的相互作用;煅烧温度为450℃,煅烧时间为4 h,活性氧化铝载体催化活性最高;单组分催化剂相比于多组分催化剂,催化活性较低,其中Mn-Ni/γ-Al_(2)O_(3)的催化活性最好,60 min COD的去除率能达到43.26%,且重复使用6次后,COD的去除率仍达35.65%,催化活性仅降低17.60%,且Mn和Ni溶出量较低,表明催化剂具有良好的稳定性和重复使用性。

In order to solve the problem of difficult degradation of the organic matter in the tail water of coking wastewater,an active catalyst with active metal oxides loaded on the alumina was prepared by impregnation-calcination method.The effects of carrier and active component type on the removal ratio of COD were investigated through ozone catalytic oxidation experiment.The experimental results show that:BET analysis reveals that Mn-Ni/γ-Al_(2)O_(3)(n_(Mn)∶n_(Ni)=2∶1)retains the mesoporous structure ofγ-Al_(2)O_(3),with a large surface area and pore volume,but the specific surface area and pore volume of the catalyst after loading decrease,and the pore size becomes larger.XPS and XRD analysis shows that Mn mainly exists in the form ofα-MnO_(2),Ni mainly exists in a mixed valence state,and there is a strong interaction between them.When the calcination temperature is 450℃and the calcination time is 4 h,the catalytic activity of activated alumina is the highest.The catalytic activity of the single-component catalyst is lower compared to the multi-component catalyst.The catalytic activity of Mn-Ni/γ-Al_(2)O_(3)is the best,reaching a COD removal ratio of 43.26%in 60 min,and the COD removal ratio still reaches 35.65%after repeated use 6 times,with only a 17.60%decrease in catalytic activity.Moreover,the leaching of Mn and Ni are low,which indicates good stability and reusability of the catalyst.