Effect of washing conditions on adsorptive properties of mesoporous silica carbon composites by in-situ carbothermal treatment

摘要

Mesoporous silicon carbon (MSC) composites were prepared by in-situ carbothermal treatment of cetyl trimethyl ammonium bromide derived from mesoporous silica. MSC composites were used as adsorbent for methylene blue (MB) removal. Research was focused on investigating effect of washing conditions (deionized water or alkali) on surface properties and adsorption capacity of MSC composites. Results showed that best adsorption performance was given by the MSC composite washed by alkali at optimum pH 13.0. Adsorption mechanism for MB removal was systematically investigated by X-ray photoelectron spectrometer analysis, adsorption isotherms, adsorption kinetics and adsorption thermodynamics. MB adsorption by the MSC composites was found to be driven by three possible schemes: physical exothermic reaction, hydrogen bonds and n-interaction. The maximum adsorption capacity was 156.56 mg/g for MSCa13. The negative values of Delta G(0), Delta H-0 and Delta S-0 indicated that the adsorption process was a spontaneous exothermic reaction. The adsorbent can be regenerated for reuse.

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