Synthesis of N,S-rich amorphous coordination polymers and the efficient CH3Hg+adsorption performance in water

In aquatic environments, CH 3 Hg + represents a persistent neurotoxin that proves challenging to eliminate. Despite the extensive efforts made by countries in mercury pollution control, it still poses a significant threat to ecological health in some underdeveloped countries and regions. This study introduces a novel amorphous coordination polymer (BD-ACP-A), synthesized through a coordination reaction involving bis(4-hydroxyphenyl) disulfide, adenine, and Cr(NO 3 ) 3 ·9H 2 O. The resulting material exhibited exceptional adsorption performance for CH 3 Hg + across a wide pH range of 2 to 11. At an initial concentration of 300 ppb, adsorption equilibrium was reached within 30 min, with an adsorption capacity exceeding 1460 μg·g −1 and a removal rate surpassing 98.0 %. BD-ACP-A also demonstrated remarkable anti-interference capabilities, maintaining high adsorption efficiency in the presence of elevated concentrations of humic acid or NaCl, as well as in various real water samples. Furthermore, it exhibited excellent reusability; at an initial concentration of 160 ppb, it retained an adsorption capacity of 718 μg·g −1 and a removal rate exceeding 89.8 % after 10 adsorption-desorption cycles. The adsorption process was well described by the Langmuir isotherm and pseudo-second-order kinetic models, yielding a maximum adsorption capacity of 138 mg·g −1 . Mechanistic investigations utilizing FT-IR, XPS analysis and DFT calculations revealed that the adsorption is primarily driven by the synergistic chelation of sulfur atoms and covalent interactions with nitrogen atoms. This work not only provides a highly efficient adsorbent for CH 3 Hg + pollution control but also presents a novel strategy for designing amorphous polymers with broad pH adaptability and rapid adsorption kinetics.