Coadsorption of gaseous xylene, ethyl acetate and water onto porous biomass carbon foam pellets derived from liquefied Vallisneria natans waste

BACKGROUND: Only a few studies have focused on the purification of waste gas containing a mixture of volatile organic compounds (VOCs) with engineered biochar. The adsorption behaviors of gaseous xylene and ethyl acetate (EA) individually and in binary mixture onto porous biomass carbon foam pellets (BCFPs) were studied by static headspace gas chromatography. RESULTS: The removal efficiency nearly reached 100% for 17.32 mg L⁻¹ xylene and 18.02 mg L⁻¹ EA within 120 min at a BCFP dosage of 0.2 g L⁻¹, a temperature of 40 °C and a relative humidity of 30%. The adsorption behavior followed the pseudo‐second‐order kinetic model for single and binary mixtures of xylene and EA. The coexistence of xylene had considerable influence on the adsorption performance of EA, whereas the coexistence of EA exhibited minimal effect on the adsorption performance of xylene. The monolayer adsorption capacities of sole xylene and EA were 250.63 and 206.61 mg g⁻¹ respectively. The total adsorption capacity reached 322.36 mg g⁻¹ for the binary mixture, but the adsorption capacity for sole xylene and EA decreased because of competitive adsorption. The adsorption process was spontaneous and endothermic. Pore filling was involved in the adsorption of xylene and EA onto BCFPs. Meanwhile, xylene adsorption was involved in the hydrophobic interaction and π–π electron dispersion interaction. CONCLUSION: BCFPs are an effective adsorbent for VOC adsorptive removal from waste gas. Competitive adsorption between xylene and EA on BCFPs was determined. Results indicated that the physicochemical properties of VOCs had an effect on the adsorption performance. © 2019 Society of Chemical Industry