A strategy for industrial waste mitigation—thermal treatment of non-woven polyester fabric debris on ultrahigh-porosity MgO under CO2 atmosphere

Abstract

Unproperly treated industrial waste creates serious environmental pollution that requires immediate remediation strategies. Non-woven polyester fabrics are widely used in a variety of industrial applications; thus, their debris becomes a major portion of industrial waste. To contribute to advanced industrial waste treatment processes, this study investigated catalytic thermal treatment of non-woven polyester fabric debris on a novel ultrahigh-porosity MgO material under a CO2 environment. The ultrahigh-porosity MgO was synthesized from hydromagnesite via a series of thermal reactions, having a surface area of 208.8 m2 g−1, total pore volume of 0.34 cm3 g−1, and average pore diameter of 2.37 nm. Using the MgO as the catalyst for thermolysis of non-woven polyester fabric debris in CO2 promoted thermal cracking of volatilized species evolved from the non-woven polyester fabric debris thermolysis, thereby increasing the gas product yield and decreasing the liquid product and wax yields. In addition, dehydrogenation and reverse water gas reaction was promoted by the MgO catalyst, leading to more than higher syngas production (up to 16.1 wt% syngas yield) compared to non-catalytic thermolysis (up to 8 wt% syngas yield). The selectivity toward esters was increased, while the selectivities toward benzoic and phthalic acids were decreased, most likely due to the MgO promoting decarboxylation and esterification reactions during the thermolysis. Moreover, the ultrahigh-porosity MgO catalyst was reusable for at least two consecutive cycles. It is hoped that the applicability of the novel material as a catalyst is widened for advanced treatment processes to minimize negative effects of industrial wastes on the environment.