The selective dissolution-precipitation recycling: A review on this alternative approach for the recovery of nylon-based waste materials

The Selective Dissolution-Precipitation (SDP) technique is emerging as a promising and sustainable method for recycling polyamide (PA) from mixed polymer waste streams. This review explores solvents reported in the literature, industrial solutions described in patents, and case studies on various PA-containing waste materials, including carpets, films, airbags, tires, and textiles. SDP addresses the challenge of recycling mixed-material waste, which cannot be processed through mechanical methods or depolymerization, and would otherwise be destined to landfills or incineration. A key advantage of SDP is its ability to preserve the intrinsic properties of recycled PA, leading to higher quality and purity compared to conventional mechanical recycling. Its versatility is supported by a range of solvents that selectively dissolve PA; however, economic and environmental sustainability remain critical considerations. Advances in bio-based solvents and solvent recovery systems further reduce the global warming potential (GWP) of SDP processes compared to virgin polymer production. Despite its potential, further research is needed to optimize solvent systems, energy efficiency, and process scalability, ensuring the feasibility and adoption of this innovative recycling technology on an industrial scale.