Liquid-liquid phase separation as a regenerative framework for adaptive and sustainable pollution management

Liquid-liquid phase separation (LLPS) offers a new perspective for environmental management by transforming molecular self-organization into adaptive and regenerative pollutant control. Unlike static sorbents that rely on rigid surface adsorption, LLPS assemblies exploit weak multivalent interactions to selectively partition solutes, reorganize in response to external stimuli, and create confined microenvironments that can support catalysis or sensing. These features collectively enable capture-respond-recover loops, in which pollutants are selectively enriched, released under mild cues, and the phase-separated assemblies re-formed for repeated use. This review integrates current progress on LLPS mechanisms, tunable coacervate systems, and pollutant-specific interactions to illustrate how soft-matter dynamics can be scaled into system-level management strategies. As a case study, micro- and nanoplastics (MNPs) exemplify how pollutants can act both as pathological phase triggers and as functional separation cues. Our recent work demonstrates that carboxylated polystyrene nanoparticles (PS-COOH NPs) induce LLPS of proteins such as VGLL3 and avian antibodies in a clear size- and concentration-dependent manner, highlighting how MNPs modulate molecular phase behavior. Quantitative immunological studies further reveal up to 128-fold increases in IgG titers against polystyrene, indicating that strong and selective molecular recognition of MNPs is achievable. When considered alongside LLPS systems that already achieve >90-99 % removal of representative contaminants under mildly regenerable conditions, these findings begin to establish quantitative benchmarks and mechanistic constraints for engineering future MNP-targeted capture-respond-recover condensates. By reprogramming these interactions, proteins and antibodies can be designed to co-condense with MNPs, forming recyclable condensates for targeted capture and reuse. This inversion from toxicity to utility illustrates the adaptive potential of LLPS for next-generation pollution control. We further discuss challenges in droplet stability, material safety, and quantitative benchmarking, proposing future directions toward LLPS-integrated adaptive management systems. This conceptual synthesis bridges molecular thermodynamics with sustainable environmental engineering, reframing pollutant remediation as a regenerative and self-renewing process.