Copper and iron sulfide on hydroxyapatite-based adsorbents for mercury removal from contaminated environments
摘要
Mercury is extensively used in artisanal and small-scale gold mining activities through amalgam formation, despite being widely recognized as a global pollutant due to its high toxicity and mobility. Responding to the urgent need for environmental remediation, highly effective adsorbents were developed by incorporating copper and iron sulfide into a hydroxyapatite matrix via coprecipitation and ion exchange methods, followed by sulfidation. These metals were successfully integrated into the hydroxyapatite structure, occupying vacancies at calcium sites. The resulting materials exhibited high specific surface areas, ranging from 79.4 to 166.1 m2 g−1, and copper and iron mass contents ranging from 4.6 to 15 wt%. Results of bath adsorption experiments revealed mercury adsorption capacities of 135.5 mg g−1 for iron sulfide-hydroxyapatite and 197.7 mg g−1 for copper sulfide-hydroxyapatite, considerably surpassing the performance of pure hydroxyapatite, which adsorbed only 2.2 mg g−1. Mercury temperature-programmed desorption confirmed the adsorbed mercury remained immobilized up to 110 °C, underscoring the material’s potential for both mercury capture and thermally stable containment. These results demonstrate the effectiveness of the synthesized adsorbents in reducing atmospheric mercury emissions from areas with elevated mercury concentrations.