ZSM-5分子筛疏水改性及催化H_2O_2氧化苯酚的性能研究

Hydrophobic Modification of ZSM-5 Molecular Sieve and Its Catalytic Performance for Phenol Oxidation with H_2O_2

以甲苯为溶剂、三甲基氯硅烷(TMCS)为表面改性剂,采用液相接枝的方法对ZSM-5分子筛进行疏水化改性,通过XRD、FTIR、N2吸附-脱附、TG、水静态吸附试验等手段对改性前后的ZSM-5分子筛进行了表征,并将其应用于苯酚的吸附及催化氧化研究。结果表明:改性后ZSM-5分子筛仍保持原有的孔道结构,-Si(CH3)3基团接枝到孔道表面,使比表面积和孔容、孔径均有下降;改性后ZSM-5分子筛水静态吸附率由3.82%降至1.12%,疏水性得到明显提高;改性后ZSM-5分子筛对苯酚的吸附机理符合Langmuir模型,吸附动力学符合准二级动力学模型,且对水中苯酚的饱和吸附量由30.7mg/g增加到36.9mg/g;疏水改性后的分子筛负载MnO2催化H2O2氧化降解苯酚的效率可达86.2%,且其吸附过程与催化氧化过程具有协同效应。

This paper conducts hydrophobic modification of ZSM-5molecular sieve using three trimethylchlorosilane（TMCS）as the surface modifier in toluene solvent by the liquid phase grafting method.Then,the paper characterizes the prepared ZSM-5molecular sieve by XRD,FTIR,N2adsorption-desorption,TG and water static adsorption experiment,and adopts it to the adsorption and catalytic oxidation of phenol.The results show that the modified molecular sieve still maintains the original pore structure with the surface area,pore volume and pore size decreasing due to the-Si（CH3）3 groups grafted onto the surface of molecular sieve pore entrances;the water static adsorption rate decreases from 3.82%to 1.12%,and the hydrophobic property obviously increases;the adsorption mechanism for phenol accords with the Langmuir model,and the kinetic model is in accordance with the pseudo-second order kinetic model,and the saturated adsorption capacity for phenol increases from 30.7mg/g to 36.9mg/g;the efficiency of oxidation degradation of phenol with H2O2 catalyzed by modified molecular sieve supported MnO2 is up to86.2%;the adsorption and catalytic oxidation have synergistic effect.