Circular economy strategies for converting waste plastics into surfactants

Upcycling waste plastics into surfactants presents a new approach toward addressing environmental concerns. Depending on the type of plastic material and the planned surfactant nature, plastics like polyethylene terephthalate, polyethylene, polypropylene, and polystyrene are converted into amphiphilic molecules bearing surfactant characteristics by various methods such as hydrolysis, catalytic functionalization, or chemical modification. The obtained novel surfactants showed low critical micelle concentration and improved emulsification, detergency, and corrosion inhibition, making them active options compared to traditional surfactants. Catalytic depolymerization and oxidation resulted in high-market-value biodegradable surfactants. Pyrolysis, enzymatic hydrolysis, and thermolysis are some of the inevitable techniques for selective transformation into high-value intermediates such as fatty acids and alkylaromatics. Moreover, the microbial metabolism of plastic-derived alkanes results in biosurfactants that provide environmentally friendly solutions for different industrial applications. These processes thus provide economic and environmental benefits following the principles of the circular economy, reducing plastic waste while providing a sustainable alternative for fossil-derived surfactants.