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Graphical abstract Highlights • Natural porous minerals were used as VOCs adsorbents. • Adsorption capacity of mineral is linearly related to its specific surface area. • Models fit breakthrough curves, isotherm and kinetic processes well. • The acid stellerite could be a promising adsorbent for VOC adsorption. Abstract The abundance of natural porous minerals and their low cost make them the potential adsorbents for VOCs (volatile organic compounds). In this paper, three natural minerals (diatomite, stellerite and vitric tuff) and their corresponding acid-treated minerals were used as adsorbents. The adsorption performances of minerals were investigated by the adsorption breakthrough curves of VOCs. The results indicated that the properties of organic compounds such as boiling point and polarity and the surface area and pore volume of minerals had obvious effects on the adsorption of VOCs over minerals. Increasing adsorption temperature and relative humidity would have negative effects on the VOC adsorption of minerals. The adsorption capacity of 2-heptanone over acid stellerite decreased by 7.2% as the temperature rose from 25°C to 45°C. The adsorption capacity of acid stellerite for 2-heptanone reduced by 60.9% when relative humidity increased from 0% to 75%. Minerals were tested for five adsorption-regeneration cycles to study the reusability. Better fittings of Thomas model, pseudo-first order kinetics model, and Freundlich model were showed in fitting the adsorption. Overall, porous minerals with high specific surface area and pore volume have promising prospect in VOCs adsorption. [ABSTRACT FROM AUTHOR]

Mesoporous silica MCM-41 was synthesized by a facile hydrothermal treatment using sodium silicate extracted from natural Opoka as the Si source. The dynamic adsorption and desorption of organic vapors mixture on the MCM-41 were investigated. Characterization of the textural properties of the samples showed that the sample synthesized with a molar ratio of CTAB/Si = 0.16 possessed the largest specific surface area (988 m2/g) and pore volume (1.02 cm3/g), also uniform pore size distribution centered at 2.8 nm. The adsorption capacity of this sample for organic vapors mixture improved remarkably over raw Opoka and reached 158.5 mg/g at 20 ℃, which is comparable to that of commercial activated carbon. The reusability of the adsorbent was tested by 5 adsorption and regeneration cycles. Obtained results demonstrate that the MCM-41 adsorbent can be easily regenerated by thermal desorption in air, and the cumulative heel on the adsorbent can be markedly reduced by increasing the desorption temperature, making it a promising adsorbent for VOCs abatement. ga1 • MCM-41 was prepared from natural Opoka via hydrothermal treatment. • Effect of template on the microstructure of MCM-41 was studied. • Synthesized MCM-41 has a much higher surface area compared to the raw opoka. • MCM-41′s VOC adsorption capacity is comparable to activated carbon. • MCM-41 can be regenerated more efficiently and easily than activated carbon. [ABSTRACT FROM AUTHOR]