Sustainable recovery of Te(IV)/Se(IV) from mixed solutions via selective adsorption-desorption on amorphous hydrous zirconium oxides: Synergistic purification and enrichment

The absorber layers of end-of-life thin-film solar cells represent valuable sources of tellurium and selenium, necessitating efficient separation and recovery strategies for sustainable resource utilization. In this work, amorphous hydrous zirconium oxides (AHZOs) were synthesized via the sol-gel method, featuring abundant surface hydroxyl groups, and enhanced specific surface area for effective Te(IV)/Se(IV) adsorption. The maximum adsorption capacities reached 743.8 mg/g for Te(IV) at pH 8 and 375.5 mg/g for Se(IV) at pH 2, driven by spontaneous endothermic processes involving synergistic mechanisms of electrostatic attraction, hydrogen bonding, ion exchange, and surface complexation. Competitive adsorption studies revealed Te(IV)’s superior binding affinity, achieving a separation coefficient up to 1609 through the selective displacement of adsorbed Se(IV). Both single and mixed solutions can be treated as wastewater with appropriate amounts of AHZOs to achieve emission standards. A stepwise adsorption-desorption strategy yielded 99.6 %-pure Se(IV)-enriched and 95.9 %-pure Te(IV) solutions, enabling effective separation and purification. Volume-controlled desorption further facilitated resource enrichment, producing concentrated solutions containing 2324 mg/L Te(IV) and 2000 mg/L Se(IV). Through adsorption and desorption, the separation and recovery of Te(IV) and Se(IV) were achieved in the simulated leaching solution with recoveries of 90.8 % and 73.9 %, respectively. This study establishes AHZOs as a promising material for sustainable metal recovery from waste photovoltaic cells, demonstrating significant potential for resource recovery in renewable energy systems.