载锰氮化碳催化臭氧法降解水中草酸研究

Degradation of oxalic acid in water by catalytic czonation with Manganese nitride carbon catalyst

草酸是废水中多种有机物氧化降解的中间产物,与臭氧反应速率很低,难以直接氧化去除。本研究通过热解法煅烧不同摩尔比例的三聚氰胺与醋酸锰(Ⅲ)二水合物,制备出不同负载量的载锰氮化碳催化剂,并研究了不同条件下载锰氮化碳催化臭氧法对草酸的降解效果,考察三聚氰胺与醋酸锰摩尔比、催化剂投加量、p H值、臭氧浓度等因素以及叔丁醇对草酸去除效果的影响。实验结果表明:相对于单独臭氧氧化而言,载锰氮化碳催化臭氧法可以极大的提高草酸的去除率,在投加0.15 g/L三聚氰胺与醋酸锰20∶1的催化剂后,草酸在60 min的TOC去除率可达到89.1%。叔丁醇加入对草酸的去除率影响较小,表明·OH在载锰氮化碳催化氧化草酸的过程中起作用但不是唯一因素。

Oxalic acid is an intermediate product of a variety of organic matters degraeed in wastewater, it is difficult to remove directly by oxidization because of its low reaction rate with ozone. A series of Manganese nitride carbon catalysts with different loadings were prepared using different molar ratios of melamine and manganese （ Ⅲ ） acetate dehydrate through the pyrolysis calcination. The degradation effects of oxalic acid by catalytic ozone with MnOx/g -C3N4 on different conditions were studied. The effects of the molar ratio of melamine and manganese（ Ⅲ ） acetate dihydrate, catalyst dosage, the pH of solution, ozone concentration and TBA on degradation of oxalic acid by catalytic ozone were investigated. The resuhs showed that, compared with ozone alone, the removal rate of oxalic acid improved greatly by catalytic ozone with MnOx/g - C3N4. The removal rate of TOC was 89.1% in 60 minute when 0.15g/L of catalytic was added, which is prepared with the mole ratio of melamine and Manganese （Ⅲ） acetate dehydrate being 20： 1. The removal rate of oxalic acid decreased slightly when tert butyl alcohol was added into aqueous solution, which proved that · OH was involved in the process of catalytic ozonation of oxalic acid but it was not the only factor to make oxalic acid degraded.