MnO_2陶粒臭氧氧化催化剂的制备及其性能

以凹凸棒土为载体、MnO_2为活性组分,制备了MnO_2陶粒臭氧氧化催化剂,并以草酸为模拟污染物,采用响应面法对催化剂的制备条件进行了优化。实验结果表明:各因素对草酸去除率影响的显著性顺序为MnO_2投加量盐酸溶液质量分数煅烧时间煅烧温度。催化剂的最佳制备条件为:MnO_2投加量200 mg/g,盐酸溶液质量分数20%,煅烧时间2 h,煅烧温度400℃。在初始草酸质量浓度150 mg/L、溶液pH 3.11、臭氧投加量8.10 mg/min、臭氧-氧气曝气量400 m L/min的条件下,最佳条件制备的催化剂在反应30 min时的草酸去除率达66.99%。催化剂具有良好的活性稳定性,且催化过程中Mn~(2+)溶出量低。催化剂具有较大的比表面积,负载的MnO_2类型为α-MnO_2和β-MnO_2。

Preparation of MnO2 ceramsite and its catalytic activity for ozone oxidation

MnO₂ ceramsite catalyst was prepared using attapulgite as carrier and MnO₂ as active component. The preparation conditions were optimized by response surface methodology using oxalic acid as simulated contaminant. The experimental results showed that the significant factors affecting oxalic acid removal rate were in the order of MnO₂ amount,hydrochloric acid solution mass fraction,calcination time and calcination temperature. The optimum conditions for catalyst preparation were as follows：MnO₂ amount 200 mg/g,hydrochloric acid solution mass fraction 20%,calcination time 2 h and calcination temperature 400 ℃. Under the conditions of initial oxalic acid mass concentration 150 mg/L,solution pH 3.11,ozone amount 8.10 mg/min,ozone-oxygen aeration rate 400 mL/min and reaction time 30 min,the removal rate of oxalic acid was 66.99%. The catalyst had good activity stability with low Mn²⁺ dissolution. Moreover,the catalyst had a large specific surface area and the types of MnO₂ supported on the catalyst were α-MnO₂ and β-MnO₂.