Use of CO2 and nylon as the raw materials for flammable gas production through a catalytic thermo-chemical process

Abstract

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 CO2 as a raw material to produce more syngas (H-2 and 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/SiO2 was tested. The catalytic capability of Ni-based catalyst led to the enhanced conversion of CO2 into CO in line with H-2 production 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 CO2 with pyrolytic products over the catalyst. CO2 also 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.