A bioinspired photothermal evaporator for enhanced salt separation during saline soil remediation

Abstract

Soil salinization is a major global challenge for agriculture and ecosystems, with current remediation methods limited by lengthy operation times, high costs, significant energy demands, risk of secondary pollution, and potential for increased soil degradation. Herein, a bioinspired photothermal evaporator (NW-PPy), created by polymerizing pyrrole to form a polypyrrole coating on a nonwoven fabric is introduced as a sustainable soil salinization reduction tool. This synthesis enhanced the material's photothermal efficiency, enabling rapid water evaporation and targeted salt extraction from soil. The NW-PPy evaporator facilitates salt migration from the soil matrix to the evaporator surface, where salt crystallization occurs above the soil surface, effectively isolating salts from the soil and reducing salinity. Under one-sun irradiation, the three-dimensional evaporator achieved a high evaporation rate of 2.47 kg m⁻² h⁻¹. A 10-day outdoor trial further demonstrated an 80 % reduction in overall soil salinity. Furthermore, plant cultivation tests to assess relative phytotoxicity indicated significant improvements in lettuce seed germination and stem growth in treated soil. Life cycle assessment (LCA) and techno-economic analysis (TEA) confirmed the evaporator's low environmental impact and economic viability, which underscored that this approach has significant potential as a sustainable solution for saline soil remediation.