Carbon Residue from Copyrolysis of Cartons and Plastics As an Efficient H₂O₂ Activator

Abstract

The recent significant increase in the amount of municipal solid waste (MSW) is a remarkable environmental issue. Pyrolysis is a promising thermal treatment process, as it can reduce MSW and produce some valuable products as well. This study evaluated the potential of the carbon residue (CR) as an efficient H 2 O 2 activator. The CR was produced from the copyrolysis of a mixture of abandoned cartons and plastic wraps, which are becoming increasingly dominant in MSW. The results show an interesting interaction between cartons and PVC, that the introduction of PVC into the carton greatly enhanced the activation rates of H 2 O 2 by CR below the ratio of 0.2:1 (PVC/ carton, w/w), whereas higher PVC content lowered its activation ability. EPR signals under different conditions revealed that CR directly activated H 2 O 2 to mainly produce • O 2 − , which was responsible for pollutant degradation. A mechanistic study suggested that the rates of H 2 O 2 activation were mainly governed by two factors: the amount of oxidative sites on CR and the conductivity of CR, which both were also quantitatively correlated with the activation rates of H 2 O 2 . Surface defects and surface-bound radicals were attributed to the two factors, respectively. The introduction of a limited amount of PVC to the carton greatly increased both factors mainly contributed from the generation of HCl during pyrolysis of PVC. In summary, this study may provide some new insights on the catalytic features of CRs, which are generated from the pyrolysis of a mixture of abandoned plastic wraps and cartons.