Reusable SnS₂-Based Cotton Fabric Composites for Efficient Decontamination of Water from Lead Ions under Continuous...

Lead is a toxic heavy metal that pollutes the environment and accumulates in the human body, causing many severe health issues. Metal sulfides have emerged as promising sorbents for rapidly decontaminating Pb²⁺-containing wastewater, showing exceptional sorption kinetics, capacities, and selectivity against common competitive ionic species. In this study, we present modified SnS₂ phases, namely, SnS₂(DMA)_0.7(H₂O)_0.3 (SnS₂/DMA, DMA = dimethylamine) and Sn_1-xS₂·yH₂O (SnS₂/acid), which demonstrated efficient removal of Pb²⁺ ions from aqueous solutions. Both materials exhibited fast kinetics (≤4 min), high sorption capacities (838.0 mg g^-1 for SnS₂/DMA and 190.0 mg g^-1 for SnS₂/acid), remarkable selectivity toward Pb²⁺ over several competing cations and in various pH values, because of strong Pb-S covalent interactions. Aiming for practical wastewater treatment, we immobilized SnS₂/DMA and SnS₂/acid on cotton fabrics, marking this as the initial application of metal sulfides immobilized onto cotton substrates. The metal sulfide-fabric composites were utilized to remove Pb²⁺ under continuous flow conditions, showing significant Pb²⁺ sorption properties. Significantly, the metal sulfide-based composites can be regenerated and reused over several Pb²⁺ sorption cycles. This feature, demonstrated for the first time in metal sulfide materials, constitutes a breakthrough for this class of sorbents.