Dehydrochlorination of polyvinylchloride using Al-modified graphitic-C3N4

Abstract

One of the efficient chemical recycling processes for waste polyvinylchloride (PVC) is the dehydrochlorination reaction using an environmentally benign solvent such as polyethylene glycol. Hydrogen chloride (HCl) is simultaneously formed through the unzipping degradation mechanism of PVC due to its lower thermal stability, this causes severe corrosion problems for the operating equipment. For the dehydrochlorination of PVC, a novel graphitic carbon nitride (g-C₃N₄) possessing a large amount of basic sites was prepared via melem-based thermal synthesis with an aluminum species structural modifier during the g-C₃N₄ preparation to verify the dehydrochlorination activity for PVC according to the aluminum content in the g-C₃N₄ matrix. The optimal 10 wt% aluminum modified g-C₃N₄ catalyst showed an excellent dehydrochlorination activity for PVC in an environmentally benign polyethylene glycol solvent due to the superior characteristics of the large amount of basic sites in g-C₃N₄. The positive effects of Al₂O₃ were mainly attributed to the incorporation of the structural modifier Al₂O₃ in the matrix of g-C₃N₄, where Al₂O₃ was a chemically inert material that enhanced the basicity of g-C₃N₄.