Composites derived from co-pyrolysis of residual biomass with aluminium slag as effective materials for volatile organic compounds removal

Abstract

Co-pyrolysis is an important method to transform hazardous waste into new materials, and composites based on biochar and metal oxides could constitute new types of adsorbents for volatile organic compounds (VOCs). In this study, residual biomass (corn cob, rapeseed and walnut shell) was co-pyrolyzed at 650OC with aluminum slag (AlS), and different composites were synthesized. Biocomposites have been used as adsorbents for the removal of VOCs (such as acetone and toluene). The results showed that the biocomposite obtained from corn cob and AlS has a higher adsorption capacity for acetone, while the composite obtained from walnut shell and AlS showed a higher adsorption capacity for toluene. All prepared composites showed a higher adsorption rate than the corresponding pure biochars. After eighth cycles of adsorption/desorption, the results obtained showed the sample AlS650-Na/BCCC presented a good adsorption performance for acetone ( 318 mg/ g) in the first three cycles, and then the adsorption capacity decreased slowly, with the increase in the number of adsorption cycles. However,the adsorption capacity of 254.41 mg/g was still high after the eighth cycles.A similar behavior was presented by the AlS325-Na/BCWS composite for toluene adsorption.Therefore,AlS/BC composites could be used as a potential adsorbents in VOCs removal.