(2021) Green Chemistry_Use of CO2and nylon as the raw materials for flammable gas production through a catalytic thermo-chemical process

Lee S., Jung S., Lin K.-Y., Tsang Y.F., Kwon E.E.

(Royal Society of Chemistry) Green Chemistry ISSN: 14639262 Vol.23 Issue.22 Article No. DOI: 10.1039/d1gc02540f

Synthetic textiles have offered a chance to enhance the quality of life since their invention. Nonetheless, the massive generation/accumulation of synthetic textile waste (STW) indeed poses numerous environmental problems. To offer a strategic disposal platform to valorize STW into flammable gas, the thermo-chemical processing of STW was studied in this work. Pyrolysis of STW was particularly studied using CO₂as a raw material to produce more syngas (H₂and CO). To this end, prior to the pyrolysis test, the main constituents in STW were determined as nylon 6. This study also found that a monomer of nylon 6 (caprolactam) could be recovered from pyrolysis of STW. However, separation of caprolactam could be challenging considering the complex compositional matrixes of STW pyrolytic oil. To enhance the formation of CO stemming from CO₂, catalytic pyrolysis of STW over Ni/SiO₂was tested. The catalytic capability of Ni-based catalyst led to the enhanced conversion of CO₂into CO in line with H2production and degradation of pyrolytic oil. The production of syngas from CO₂-assisted catalytic pyrolysis was 7 times larger than the reference one arising from increased CO formation by catalytic reaction of CO₂with pyrolytic products over the catalyst. CO₂also offered a great chance to suppress catalyst deactivation by suppression of coke deposition or removal of coke deposited on the catalyst surface. All experimental findings of this study could offer an effective guideline for a thermo-chemical disposal platform for nylon while mitigating a hazardous potential in ecosystems. © The Royal Society of Chemistry 2021.

This work was supported by National Research Foundation of Korea (NRF) grants funded by the Korean government (MSIT) (NRF-2019R1A4A1027795 and NRF-2021R1I1A1A01052241).