Natural Vermiculite Slice Modified by CTAB and Zirconium for Selective Adsorption of Phosphate

This study delves into the potential of vermiculite-based adsorbents for phosphate removal from aqueous solutions. CTAB and zirconium-modified natural vermiculite slices (CZV) were employed, with XRF analysis confirming successful zirconium loading. The Langmuir model indicated monolayer adsorption behavior, suggesting a preferential adsorption characteristic. The presence of coexisting ions showed varied effects on phosphate removal, with increasing CO 3 2− concentrations slightly inhibiting phosphate removal by CZV, while increasing NO 3 − , SO 4 2− , and Cl − concentrations improved phosphate removal by all adsorbents. Notably, the vermiculite adsorbents, despite their larger particle size, demonstrated a competitive adsorption capacity when compared to other adsorbents. The practicality of these adsorbents is further emphasized by their potential direct application in artificial wetlands and lakes without posing ecological risks. Moreover, the reutilization of used vermiculite adsorbents is highlighted as a sustainable approach, considering their beneficial effects on the growth of submerged macrophytes and sediment microecological environments. The adsorption mechanism is attributed to surface complexation and ligand exchange. This research underscores the efficacy of modified natural vermiculite slices in phosphate adsorption, paving the way for broader environmental applications and offering a promising solution to water purification challenges.