The Study On Zeolite From Coal Fly Ash For VOCs Adsorption

The main content of this paper is the study of application of coal fly ash for VOCs control,and a new solution for VOCs adsorption to alleviate the pressure of environment and then achieve the purpose of waste treatment effect,which was brought by coal fly ash pollution.Coal fly ash can be converted into zeolite for its similar chemical composition with zeolites.The article included synthesizing zeolite from coal fly ash,characterizing the crystal morphology,surface features and chemical composition of zeolite,and analyzing the adsorption capacity,adsorption mechanism of VOCs on zeolites.The article explored the influence of acid solution,crystallization time,crystallization temperature and NaOH alkali solution on zeolite and analyzed the characterization of synthetic results.1.According to the characterization results,the main component of the synthetic samples is the SAPO zeolite.The specific surface area and pore volume of the synthesized sample are significantly increased compared to coal fly ash.The zeolite has the largest specific surface area and pore volume,when the concentration of hydrochloric acid is 25wt%,the crystallization time is 7h,the crystallization temperature is 120°C,and the NaOH alkali is 8mol/L.2.Adsorption measurements for benzene and xylene were tested on synthetic samples and coal fly ash.Adsorption results showed that the adsorption capacity of each sample was greatly improved compared to coal fly ash.The adsorption capacity of benzene and xylene was the largest,when the concentration of hydrochloric acid is25wt%,the crystallization time is 7h,the crystallization temperature is 120°C,and the concentration of NaOH alkali is 8mol/L.The maximum adsorption of benzene was87.246mg/g,and the adsorption amount of xylene was 120.664 mg/g.3.The adsorption capacity of xylene on zeolite is larger than that of benzene,and the adsorption process is more consistent with Lagergren's second-order kinetic model.Besides,the adsorption isotherm is more aligned with the Freundlich adsorption isotherm.