Super stable evaporators based on upcycled self-healing adsorbents for wastewater regeneration

Abstract

Interfacial evaporation systems have enormous potential for wastewater treatment and freshwater generation. However, a technological gap remains in achieving a sustainable solar-driven water purification system that combines rapid evaporation rates with enhanced stability. With this research, we investigated a self-healing water purification platform that incorporates cellulose nanocrystals that encapsulate polyaniline into a PVA–borax dynamic crosslinked network, which is capable of effectively enriching heavy metal ions and generating clean water. The wastewater regeneration system was developed to remove heavy metal ions through adsorption, then the hydrogel was recovered through self-healing for use as an interface evaporator for secondary purification of the wastewater. Combining an exhausted self-healing gel with different substrates using the self-adhesive properties, a dual-layer evaporator with excellent water evaporation performance was fabricated. A cotton thread evaporator achieved a high evaporation rate of 2.19 kg m⁻² h⁻¹ under 1 sun. Subsequent, purification of wastewater meets with the WHO drinking water standards following the adsorption–evaporation purification process. This strategy provides an efficient, green, and sustainable approach for achieving wastewater regeneration and heavy metal-free drinking water.