CeO2改性MnO2/γ-Al2O3催化剂制备及对高浓度PNP废水微波催化氧化

Preparation of MnO_2/γ-Al_2O_3 catalysts modified by CeO_2 and its catalytic oxidation of p-nitrophenol wastewater under microwave

一步浸渍焙烧法制备了掺杂不同含量CeO2的MnO2/γ-Al2O3催化剂,考察了不同焙烧温度对催化剂活性的影响,通过XRD测定了晶型,在微波反应器中以滴流床的形式考察了其催化氧化降解对硝基酚(PNP)的效果,并对催化氧化过程进行了初步的探讨。结果表明,350、500℃焙烧的催化剂为无定形态,700℃为Mn2O3,在微波功率800W,催化剂加量15g,TOC3000mg/L、pH值为6的PNP废水滴流速度为3mL/min条件下,350℃合成CeO2含量为4%MnO2/γ-Al2O3对PNP最高去除率为92.9%,加入羟基自由基抑制剂叔丁醇(TBA)研究发现该催化氧化过程中可能有·OH产生。

A series of MnO2/γ-Al2O3 catalysts modified by different amount of CeO2 were pre-pared by one-step impregnation-calcinations’ process,the optimal combination were calcined at different temperature of 350,500,700℃,by the time, XRD was used to identify their crystallites.The effect of the catalysts on degradation of the refractory p-Nitrophenol was investigated in a trickle bed reactor in microwave oven.The results showed that the crystal forms of catalysts calcinated at 350,500°C were amorphous,and 700℃ was Mn2O3.The highest removal rate of PNP was 92.9%,while the catalyst 15g with the CeO2 content was 4% and TOC of PNP was 3000mg/L,pH6,and its dropping rate was 3ml/min under 800W power of microwave.Addition of inhibitor on free radical（tert-butyl alcohol） showed that the oxidation process maybe followed the free radical reaction mechanism.