Resource utilization and catalytic pyrolysis conversion mechanism of polyacrylate solid waste

Abstract

It is a great challenge for the sustainable production and application of water-based coatings and inks in terms of realizing the green resource utilization of polyacrylate solid waste (PSW) and avoid its secondary pollution. In this paper, the pyrolysis of PSW catalyzed by HZSM-5 in a fixed bed was investigated, and its reaction conditions were optimized by a Box-Behnken design. The results indicated that PSW could be translated into benzene, toluene and xylene (BTX) with a molar carbon yield of up to 51.24 % at the optimized conditions, which is much higher than those of the solid waste catalytic pyrolysis by HZSM-5 reported in existing literatures. The yield and composition of BTX products were significantly influenced by the structural characteristics of PSW. TG-MS indicated that the conversion process of PSW to BTX through monomer cracking, dealkylation of aromatic hydrocarbons, dehydrogenation of alkanes and aromatization of alkynes/alkenes. Among them, the catalytic effect of HZSM-5 on the dealkylation reaction of catalytic pyrolysis of PSW was proposed for the first time. Benzene was mainly derived from dealkylation and aromatization, whereas toluene and xylene were mainly derived from aromatization. The results enriched the existing mechanism of solid-waste catalytic pyrolysis using HZSM-5 to prepare BTX.