Valorization of synthetic textile waste using CO2 as a raw material in the catalytic pyrolysis process

Abstract

Since an invention of synthetic fibers (textiles), our life quality has been improved. However, the cumulative production and disposal of them have perceived as significant since they are not biodegradable and hard to be upcycled/recycled. From washing textiles, microplastics are released into the environment, which are regarded as emerging contaminants. As a means for source reduction of microplastics, this study proposed a rapid disposal platform for waste textiles (WTs), converting them into value-added products. To this end, catalytic pyrolysis of WT was studied. To offer more environmentally sound process, CO2 was used as a raw material for WT pyrolysis. Thermal cracking of WT led to the production of syngas and CH4 under the CO2 environment. CO2 resulted in additional CO production via gas phase reaction with volatile compounds evolved from pyrolysis of WT. To expedite the reaction kinetics for syngas formation, catalytic pyrolysis was done over Co-based catalyst. Comparing to non-catalytic pyrolysis, CO2-assisted catalytic pyrolysis had 3- and 8-times higher production of H2 and CO, respectively. This process also suppressed catalyst deactivation, converting more than 80 wt% of WT into syngas and CH4. The more generation of CO from the use of CO2 as a raw material offers an effective means to minimize the formations of harmful chemical species, such as benzene derivatives and polycyclic aromatic hydrocarbons.