NH2-pectin/sorghum stalk composite solar evaporator for efficient microplastics removal and sustainable freshwater generation via interfacial engineering

Microplastics (MPs) pollution and freshwater scarcity have emerged as one of the most severe global environmental crises, while conventional removal methods often suffer from inefficiency and secondary pollution. Here we developed an interfacial solar evaporator composed of a functional pectin-NH 2 /sorghum stalk (PUS) hydrogel for simultaneous freshwater production and MPs removal. The PUS system achieved evaporation rates of 3.48 ± 0.15 and 3.29 ± 0.07 kg·m −2 ·h −1 in realistic seawater and influent wastewater, respectively. Notably, flow cytometry and in-situ Raman analysis confirmed the effective removal of MPs in seawater (90.24 %) and wastewater (87.14 %). Further long-term experiments (30 d) exhibited evaporation rates of 19.45 ± 1.61 and 19.19 ± 1.43 kg m −2 ·d −1 in seawater and wastewater, respectively. Density functional theory (DFT) and molecular dynamics (MD) simulations identified that van der Waals interactions and hydrogen bonding (NH…O=C and NH…O–C) synergistically govern MPs capture and PUS structural stabilization. Techno-economic analysis (TEA) confirmed a competitive freshwater production cost of 0.12 USD/kg, underscoring the feasibility of large-scale MPs-removing solar evaporation technique. This study reveals the industrial potential of natural functional polysaccharide hydrogels and lignocellulose in freshwater production and deeps the adsorption mechanisms of functional pectin with MPs, which provides new strategies to remove MPs and produce fresh water.