Remediation of Pb²⁺-contaminated groundwater in mining areas using zeolite derived from lithium porcelain clay...

The management of mine tailings and remediation of lead (Pb) pollution represent significant global challenges. This study presents a sustainable approach by converting lithium porcelain clay tailings (LPCT) into highly crystalline Na-faujasite zeolite for efficient Pb²⁺ removal. The synthesis conditions were optimized, and the framework evolution mechanism was elucidated: four-membered rings → six-membered rings → β-cages → faujasite supercages → crystalline faujasite. The synthesized zeolite exhibited a high Pb²⁺ adsorption capacity of 584.12 mg/g and a removal efficiency of 99.7%. In actual mining area groundwater, it achieved over 99% Pb²⁺ removal with a high distribution coefficient (K_d) of 3.3 × 10⁵ mL/g, demonstrating excellent selectivity. Mechanistic studies revealed that ion exchange serves as the primary adsorption mechanism (contributing approximately 78%), supplemented by electrostatic interactions and surface complexation. The zeolite structure remained stable and could be effectively regenerated using 1 M NaCl, maintaining a high adsorption capacity (>85%) after five consecutive cycles. Preliminary environmental benefit analysis indicates that this "waste-to-resource" approach not only reduces tailings disposal but also exhibits a significantly lower carbon footprint compared to conventional zeolites and activated carbon during synthesis, highlighting its circular economy and environmental synergies. The study further discusses the potential and challenges for the industrial-scale application of this technology. This work provides a dual-benefit strategy for tailings valorization and effective remediation of Pb²⁺-contaminated water.