Preparation And Adsorption And Catalytic Properties Of Hydrophobic ZSM-5 Zeolites

Adsorption of phenol from aqueous by ZSM-5 molecular sieve with hydrophobicity was investigated. Hydrophobic ZSM-5 molecular sieve loaded with active ingredient was prepared to study the catalytic activities in the wet catalytic peroxide oxidation reaction.The hydrophobic ZSM-5 molecular sieve was prepared by organic modification of silica. The effects of methods of modification and organic reagent species as well as the reaction conditions(including temperature, reaction time, the amount of organic reagent) were investigated. The physical properties of the hydrophobic ZSM-5 molecular sieve were characterized by X-ray diffraction, N2 adsorption-desorption and FT-IR. Experimental results showed that the hydrophobicity increased significantly due to the grafted —Si(CH3)3 group within pore. The hydrophobic ZSM-5 molecular sieve was prepared with trimethylchlorosilane in toluene solvent. And at 50℃, when the modified time was 5 hours and the amount of organic reagent was 30 mL, the absorption rate for the vapour of water was 1.12%.The adsorption properties of this material toward phenol were studied. The hydrophobic ZSM-5 molecular sieve showed a higher adsorption rate toward phenol, and with the hydrophobicity improved, the adsorption capacity was higher. Hydrophobic material for the adsorption of organics in wastewater had a certain applications.The equilibrium isotherm for phenol uptake corresponds closely to the Langmuir model. The adsorption of phenol occured at the surface and adsorption energy on surface was the same. The adsorption process attributes to pseudo secondorder kinetics model, and the adsorption capacity obtained fitting with pseudo secondorder kinetics model and the actual measured qe(measured) were very close.The degradation efficiency of phenol with hydrophobic ZSM-5 molecular sieve loaded with MnO2 compared with the pure ZSM-5 increased from 60.2% to 80.1%, increased by 19.9%, compared with hydrogen peroxide oxidation of phenol increased by 73.2%, and compared with single adsorption of phenol increased by 59.1%. TOC conversion rate was up to 60% by the hydrophobic ZSM-5 molecular sieve loaded with MnO2. The hydrophobic material showed a better catalytic activity in the wet catalytic peroxide oxidation reaction, making it a possibility for the practical wastewater treatment.