Hydrolysis of Plastic Waste as a Sustainable Pathway for Polymer Recovery and Material Regeneration

Plastic waste has become an issue of serious concern because it is persistent, not biodegradable, and greatly inefficient to recycle. The traditional mechanical type of recycling is restrained by the degradation and contamination of plastics, whereas the thermochemical process typically requires large energy inputs and yields complicated by-products. Hydrolysis also presents a scientifically viable alternative, which will allow chemical depolymerization of condensation-type plastics (polyethylene terephthalate (PET), polyamides (PA), polyurethanes (PU)). The reaction works through cleavage of the ester, amide, or urethane bonds in the presence of water, acids, or bases as reactants to generate high-purity monomers that can be repolymerized or used in industry. In this paper, the performance of hydrolysis-based plastic waste recycling has been reviewed, including the mechanisms, catalyst development, process parameters, and relative environmental performance. According to life-cycle and techno-economic analysis, hydrolysis will prove to be capable of generating significant carbon reductions and energy savings compared to pyrolysis and incineration with the optimization of reaction conditions and solvent recovery systems. Although scaling, reactivity, and purification of monomers are still problematic, heterogeneous catalysis, solvent engineering, and integration of renewable heat development all increase the promise of using heterogeneous catalysis as an effective tool in ensuring sustainable polymer recycling and material recycling.