Reduction of non-methane hydrocarbons in cooking oil fumes via adsorption on MFI: Effect of zeolitic framework composition

Abstract

The growth of public awareness of hazard from gaseous pollutants emitted by cooking activities spawned the implement of new laws & regulations as well as new technologies for cooking oil fumes emission control. Considering the emission characteristics of large air volume and intermittence of cooking fumes, in this work, TS-1 was firstly applied as an efficient adsorbent for enriching the low-concentrated complex humid volatile organic compounds (VOCs) from cooking oil fumes. In order to illustrate the superiority of Ti-O-Si framework as a cooking VOCs adsorbent, zeolites with the same MFI topology to TS-1 but different framework compositions of Si-O-Al (ZSM-5) and Si-O-Si (silicalite-1, hereinafter referred as S-1) were also investigated for comparison. Related characterizations were performed to reveal the difference among three zeolites. It was found that textural properties, surface silanol density and defect content significantly affect the adsorption site accessibility, water resistance as well as organophilicity of zeolites adsorbents, all of which play a decisive role in the adsorption process of cooking oil fumes. Both TS-1 and S-1 present much stronger water resistance than commercial ZSM-5 due to lacking hydrophilic Si-OH-Al groups (S-1 > TS-1 > ZSM-5), while TS-1 shows better organophilic property than both S-1 and ZSM-5 (in an order of TS-1 > ZSM-5 > S-1) due to the physical and electrical interaction between Ti-contained framework and organic molecular. These characteristics jointly make the zeolite with Ti-O-Si framework be a good adsorbent candidate for VOCs elimination from cooking fumes.