Efficient selective uptake of Hg(Ⅱ) using a porous organic polymer rich in N and S atoms

Abstract

The escalating issue of mercury (II) ions (Hg2+) pollution in water, primarily due to human activities, poses a significant environmental and health risk. Addressing the urgent need for efficient Hg2+ removal, this study introduces a novel porous organic polymer (TpTHU) synthesized through Schiff base condensation of thiourea (THU) and 1,3,5-Triformylphloroglucinol (Tp). TpTHU, enriched with sulfur and nitrogen, facilitates soft–soft interaction with Hg2+, offering a potent solution for mercury contamination. Our experimental results demonstrate TpTHU's remarkable adsorption capacity for Hg2+, reaching 1250 mg/g, attributed to its dense complexation sites. The adsorption behavior aligns well with the Brouers-Sotolongo model. Notably, TpTHU achieves 99.25% mercury removal within 120 min over a broad pH range (4 to 10), underscoring its rapid action. Additionally, in fixed-bed column experiments, TpTHU effectively lowers Hg2+ concentrations in industrial wastewater from 10.0 mg/L to below 5 μg/L, surpassing industrial emission standards. Through XPS analysis and density functional theory calculations, we elucidate the adsorption mechanism, affirming TpTHU's efficiency. With its straightforward synthesis, high efficacy, and excellent reusability, TpTHU emerges as a promising candidate for mitigating Hg2+ pollution in industrial wastewater.