Preparation of hypercrosslinked porous polymer modified with paired thiol groups via in-situ disulfide bond cleavage for the rapid and efficient adsorption of mercury ions from water

A hypercrosslinked porous polymer (HCP) containing disulfide bonds (HCP-DS) was synthesized via a Friedel-Crafts alkylation reaction of benzyl disulfide. Subsequently, in-situ cleavage of the disulfide bonds by tris(2-carboxyethyl)phosphine hydrochloride in HCP-DS enhanced the specific surface area of the HCP, and resulted in numerous paired thiol groups in the HCP (HCP-PSH). As a reference, benzyl mercaptan was hypercrosslinked to produce HCP-ISH that thiol groups irregularly distributed in the HCP. HCP-PSH exhibited an impressive adsorption capacity and fast adsorption speed. The capacity reached 2221.2 mg·g −1 when [Hg 2+ ] = 600 mg·L −1 . The adsorption could rapidly reach 96 % of its equilibrium capacity within just 10 min. HCP-PSH showed great adsorption capacity in a wide pH range, even pH = 0.5, it also showed high adsorption capacity. Additionally, HCP-PSH demonstrated excellent selectivity for mercury ions, even in the presence of competing metal ions, underscoring its potential for practical applications. The material also showed outstanding reusability, maintaining its performance over five adsorption/desorption cycles. HCP-PSH demonstrated superior adsorption performance compared to HCP-ISH without the paired thiol groups in the same adsorption condition, indicating that paired thiols are more effective for mercury ion adsorption.