Thiazolo[5,4-d]thiazole conjugated microporous polymers for efficient removal of Hg(II) from wastewater

With mercury pollution causes serious threats to ecosystems and human health because of its extreme toxicity and bioaccumulation, the development of efficient removal technologies has become an urgent environmental priority. This study introduces a novel adsorbent thiazolo[5,4-d]thiazole conjugated microporous polymer (TzTzCMP) for efficient Hg(II) removal from wastewater. TzTzCMP synthesized via condensation of dithiocarbamate and triformyl-phenol, exhibits a coral-like porous structure with a high specific surface area of 436.86 m²/g and sulfur-rich active sites containing 15.15 wt% sulfur, enabling exceptional Hg(II) adsorption. Experiments demonstrated rapid kinetics, reaching equilibrium within 10 min, and a maximum adsorption capacity of 1050 mg/g. The adsorption kinetics and isotherm data for Hg(II) on TzTzCMP are well described by the pseudo-second-order and Langmuir models, respectively, indicating that chemical interactions dominate the adsorption process. The material maintained >95 % efficiency over five regeneration cycles and showed good selectivity under coexisting ion interference, attributed to Hg(II) coordination with N/S atoms in TzTzCMP, as confirmed by X-ray Photoelectron Spectroscopy (XPS) analysis and density functional theory (DFT) calculations. Fixed-bed column tests achieved 99.99 % removal, reducing effluent concentration to 1 μg/L and meeting drinking water standards. Combining high adsorption capacity and removal rate, rapid adsorption efficiency, good stability and reusability, TzTzCMP presents a promising solution for industrial Hg(II)-contaminated wastewater treatment.