Novel SO₄^2‐/ Tin (IV) Phosphate Nanomaterial for Selective Pb²⁺ Removal and Efficient Synthesis of Dihydropyrimidinone and Xanthene Derivatives

From a sustainable chemistry perspective, the development of materials with multiple functionalities for solving both environmental and pharmaceutical challenges is critical. This study presents a series of ammonium sulfate-supported tin (IV) phosphate (AS/SnP) composites with different loadings of AS, intended for two purposes: wastewater treatment and environmentally friendly catalysis. Various techniques, TGA, FTIR, XRD, TEM, XPS, and EDX, were utilized to investigate thermal stability, structural integrity, morphology, and functional groups. TGA analysis confirmed the high thermal stability of AS/SnP, while XRD revealed that the composites retained their amorphous nature, preserving the original SnP structure. TEM images reflected the morphological changes by the incorporation of AS, leading to more spherical and smaller nanoparticles. 25AS/SnP-II composite displayed the highest acid strength as the optimal composition, enabling efficient catalytic synthesis of 3,4-dihydropyrimidinones and 14-aryl-14H-dibenzoxanthenes. Furthermore, the adsorption behavior of AS/SnP-II for Pb²⁺ removal from aqueous solutions was systematically evaluated under varying conditions, involving contact time, initial ion concentration, adsorbent amount, and pH. 10AS/SnP-II exhibited the highest Pb²⁺ removal efficiency (98.4 %) with the process following a pseudo-second-order model (R² = 0.9923). The chemical stability of SnP-II was demonstrated by its activity within five successive cycles. These results indicate the dual functionality of AS/SnP composites as effective materials for wastewater purification and catalytic applications, providing an eco-friendly solution for environmental restoration.