This in vitro study presents a novel, cost-effective method for synthesizing MER zeolite from natural stellerite to remove toxic heavy metals like lead (Pb²⁺) and cadmium (Cd²⁺) from wastewater. The synthesized MER zeolite demonstrated outstanding removal efficiencies—99.7% for Pb²⁺ and 99.9% for Cd²⁺—across a broad pH range and in the
