A single-step upcycling of PVC-containing municipal solid waste compositions for greener chemicals and clean solids as fuel or oil absorbent

Abstract

Polyvinyl chloride (PVC) containing municipal solid waste (MSW) streams are difficult to recycle and mostly landfilled due to various detrimental effects PVC causes to waste recycling. In this work, a single-step upcycling of PVC-containing commingled wastes in tetrahydrofuran was investigated using cellulose, PVC, polyethylene (PE), polypropylene (PP), and polystyrene (PS) to model the wastes. During the co-conversion, in-situ produced HCl derived from PVC decomposition acted as an acid catalyst to selectively decompose cellulose into liquid mainly containing levoglucosan (LGA) and furfural. It was also found that the presence of PE, PP, and PS in the mixture synergistically enhanced the cellulose-derived monomer productions and increased the reaction rate for producing the monomers by suppressing secondary reactions of HCl in the solvent. The maximum LGA yield from co-conversion of cellulose, PVC, and PS was 35.4% after a 5 min reaction compared to the 31.7% obtained without PS in the mixture. In addition to converting cellulose to chemicals, PVC-derived polyaromatics and partly decomposed PE, PP, and PS were recovered as solids. The dechlorinated solids had higher heating values up to 46.11 MJ/kg, achieved by co-converting cellulose, PVC, and PP. When used as oil absorbents in water, the solid recovered from converting cellulose, PVC, and PE mixture showed the highest absorption capability. Overall, the presented approach offers a promising way for upcycling PVC-containing wastes in which PVC properties and its molecular structure are leveraged to enhance the conversion.