| Volatile Organic Compounds(VOCs)are gradually gaining importance because of their toxicity,carcinogenicity and pollution.Adsorption method has gradually become the focus of research on VOCs removal technology at home and abroad due to its low cost,low energy consumption,high efficiency and flexible and simple operation.Conventional activated carbon has a disordered structure and closed pore channels,which limits the rapid adsorption of VOCs.At the same time,the actual industrial flue gas contains a large amount of moisture,which will compete with VOCs for adsorption,thus reducing the adsorption efficiency of VOCs.Therefore,this paper firstly uses zeolite template carbon(ZTC)prepared by using β zeolite molecular sieve as a template with the advantages of large specific surface area and regular and ordered pore channels to improve the fast and large capacity adsorption of VOCs,and adopts hydrophobic polydivinylbenzene(PDVB)physically mixed with ZTC for high humidity environment to enhance the hydrophobic performance of the adsorbent surface and achieve the goal of selective adsorption of VOCs in high humidity environment.In this paper,PDVB/ZTC samples with good hydrophobic properties were prepared,and the morphological structure and hydrophobic properties of ZTC and PDVB/ZTC samples were characterized and analyzed by different characterization methods such as BET,XRD,SEM,water contact angle,and water vapor adsorption.The performance of benzene,toluene and m-xylene adsorption under high humidity environment was also investigated,and the mechanism of hydrophobic performance of PDVB/ZTC samples under aqueous environment was investigated at the microscopic molecular level by using computational simulations to further corroborate the experimental results.The study in this paper shows that:The adsorption capacity of the original ZTC samples was 140.856 mg/g for benzene,199.116 mg/g for toluene and 209.316 mg/g for m-xylene under dry conditions,and the regeneration performance of the ZTC samples was good,and the regeneration rate of the ZTC samples after five consecutive cycles of adsorption-desorption experiments still exceeded 95%.The adsorption effect of ZTC samples on VOCs was seriously inhibited by high humidity,and the 60 min cumulative adsorption capacities of the original ZTC samples on toluene,benzene and m-xylene decreased by 56.0%,45.2%and 56.1%,respectively,under 7%moisture content,and by 77.0%,77.9%and 80.7%,respectively,under 15%moisture content.The PDVB/ZTC samples modified by blending with PDVB significantly improved the adsorption of VOCs in high humidity environment,the adsorption capacities of PDVB/ZTC-3 for toluene,benzene and m-xylene under 15%moisture content increased by 205.2%,198.2%and 237.0%,respectively,compared with the original ZTC.And the water contact angle of the PDVB/ZTC-3 sample with the best hydrophobic performance was 138°,which was much higher than that of the original ZTC at 48°.The effect of water on the adsorption diffusion of VOCs was calculated using the giant canonical Monte Carlo method,and the results showed that the addition of water molecules decreased the adsorption density of VOCs in the ZTC model and inhibited the adsorption of VOCs by ZTC.The water contact angle was simulated by molecular dynamics,and the results showed that the water contact angle on the solid surface increased from 80° to 134° after carrying vinyl.The adsorption energy analysis results showed that the adsorption energy of unmodified ZTC to water was-5.077 eV,and the adsorption energy of hydrophobically modified ZTC to water was-4.787 eV,and the mutual gravitational force of ZTC to water was changed to mutual repulsive force.By simulating the diffusion process of water molecules in the hydrophilic/hydrophobic channels,it was shown that the hydrophobic group introduced by PDVB accelerated the diffusion rate of water molecules on its surface and promoted the behavior of water molecules escaping out of the channels. |
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