Physico-chemical properties and adsorption characteristics of chars produced in the co-pyrolysis of biomass, plastic and tire wastes

The present work aims to perform a multistep upgrading of chars obtained during the co-pyrolysis of plastics, biomass and tire wastes and evaluate the quality of the upgraded chars by measuring some of their physico-chemical and textural properties. The chars were submitted to a sequential solvent extraction with organic solvents of increasing polarity followed by a heat treatment and finally the char samples were subjected to an acidic demineralization procedure in order to reduce the ash content. The quality of the upgraded char was evaluated by measuring both the iodine and methylene blue numbers and by the estimation of the surface area, pore volume and pore size parameters. The results showed that the acid treatment is complementary of the solvent decontamination in the upgrading of pyrolysis chars. The upgraded char reveals itself as a mesoporous material having sufficient quality to be reused as adsorbent or as precursor for high value activated carbon.