One-step synthesis of thiol-functionalized metal coordination polymers: effective and superfast removal of Hg (II) in the different matrices to ppb level

• Published in: Chemosphere (Oxford) Vol. 338; p. 139618
• Main Authors: Li, Mingzhi, Tuo, Yongjie, Wu, Qiuxia, Lin, Haiying, Feng, Qingge, Duan, Yu, Wei, Junqi, Chen, Zixuan, Lv, Jiatong, Li, Lianghong
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.10.2023
• Subjects: DFT calculation and molecular orbital theory; Mercury removal; Metal coordination polymers; Sulfur-containing ligands; Water decontamination; Mercury removal; Sulfur-containing ligands; Metal coordination polymers; Water decontamination; DFT calculation and molecular orbital theory
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2023.139618

The mercury in water bodies has posed a great threat to the environment and humans, and removing mercury and purifying wastewater has become a global environmental issue. Adopting Zn(II) coordination polymers (Zn-CPs) emerged as a new approach, however, the kind of Zn-CPs, which solely consisted of amino groups, exhibited unsatisfactory performance in capturing Hg(II) at a low level and causing the subsequent leaching of Zn(II) after adsorption. In this study, we fabricated the thiol-modified Zn-based coordination polymers (Zn-CPs-SH) through a one-step solvothermal reaction to efficiently capture Hg(II) from wastewater. Its preeminent adsorption performance could be maintained across a broad range of pH (2–7), ion strength (Cl−, SO42−, and NO3− at 0–10,000 mg/L), and dissolved organic matter (0–100 mg/L). The impressive properties, including fast kinetics (k2∼1.01 × 10−4 L/min), outstanding adsorption capacity (1278.72 mg/g, 298 K), superior selectivity (Kd∼2.3 × 104 mL/g), and excellent regeneration capability (Re = 93.54% after 5 cycles), were attributed to the ultra-abundance of adsorption sites donating from thiol groups, which was revealed by XPS analysis, DFT calculations, and molecular orbital theory. Noteworthy, the high practical application potential of Zn-CPs-SH was demonstrated by its outstanding Hg(II) removal efficiency (Re ≥ 99.10%) in various Hg(II)-spiked water matrices, e.g., tap water, river water, and industrial wastewater. Importantly, the residual Hg(II) in the treated water declined to the ppb level without any Zn(II) leaching. Overall, it is highly anticipated that the incorporation of Zn-CPs-SH would facilitate the practical implementation of highly efficient Hg(II) removal in wastewater treatment owing to its exhibiting high selective affinity, superior adsorption capacity, and enhanced efficiency. [Display omitted] •Zn-CPs-SH exhibited a prominent Hg (II) adsorption capacity of 1278.72 mg/g at 298 K.•The complexation of thiol groups was the dominante contributor.•Zn-CPs-SH achieved superior capture performance in various complex matrixes.•Zn-CPs-SH was synthesized via an easy-to-operate solvothermal reaction.•The mechanism was further revealed by DFT calculation and MO theory.