A Dual‐Pathway Strategy for Upcycling Molybdenum Tailings Into Dual Adsorbents for High‐Efficiency Nutrient Control and Recovery

ABSTRACT

The large‐scale accumulation of molybdenum tailings (MT) presents a dual challenge: a significant environmental liability and a squandered resource of valuable aluminosilicates. To address this, we propose a dual‐pathway strategy that upcycles MT into two adsorbents for efficient nutrient control and recovery within a circular economy model. Initial characterization confirmed MT as a non‐hazardous, silica‐alumina‐rich precursor (Si avg. 45.8%). The strategy involves two concurrent pathways: (1) the solid residue of pretreated MT was hydrothermally converted into a FAU‐type zeolite (MTZ‐3), which achieved rapid ammonia adsorption (17.0 mg/g) and reached equilibrium within 30 min; and (2) the acidic leachate was reutilized to synthesize calcium‐iron metal oxides (CaFeMOs), exhibiting a phosphate adsorption capacity of 90.0 mg/g. CaFeMOs also reduced leachable phosphorus from phosphogypsum by more than 96% at a dosage of 2%. This “one‐waste, two‐products” approach valorizes mining waste while producing adsorbents for nutrient removal from eutrophic waters. Nutrient‐saturated adsorbents may further serve as low‐cost fertilizer carriers for nitrogen and phosphorus recovery and reuse. Overall, the strategy links molybdenum tailings valorization with aqueous nutrient capture, transforming a linear waste problem into a circular, value‐added resource recovery pathway.