基于催化臭氧氧化水溶液中氨氮的Mg/Mn催化剂制备研究

Preparation of Mg/Mn Catalyst for the Oxidization of Ammonium-nitrogen from Water Based on Catalytic Ozonation

采用均匀共沉淀法制备Mg/Mn复合金属氧化物催化剂,研究该催化剂对水中低浓度氨氮的催化降解性能。利用扫描电子显微镜(SEM)、氮吸附分析对制备的催化剂进行表征,研究制备工艺条件对催化剂微观结构、比表面积和对氨氮催化降解的影响,探讨了催化剂降解氨氮的机理。结果表明,500℃煅烧4 h得到的Mg∶Mn摩尔比为8∶2的催化剂表现出较高的催化活性,且对气态含氮物质的选择性最好,催化剂成絮状结构,表面蓬松且粗糙,比表面积为31.884 5 m2/g。Mg/Mn复合金属氧化物催化臭氧氧化氨氮的机理为Mg/Mn催化O3分解产生(·OH),从而降解氨氮。

Mg/Mn composite metal oxide catalyst was prepared by homogeneous coprecipitation method. Catalytic degradation of ammonium in its low concentration solution was studied. The prepared catalysts were characterized by SEM and nitrogen adsorption analysis to investigate the effects of preparation conditions on microstructure, specific surface area and catalytic oxidation on NH4^＋. The mechanism of ammonia nitrogen oxidation was then discussed. The experimental results show that the catalyst with Mg/Mn molar ratio of 8：2 calcined under 500 ℃ for 4 h had higher catalytic activity and the best selectivity for gaseous nitrogenous material. The catalyst had floeculent structure, fluffy and coarse surface with specific surface area of 31. 884 5 m^2/g. The mechanism of NH4^＋-N oxidation in water by Mg/Mn composite metal was thorough hydroxyl radicals produced by ozone＇s decomposition.