Preparation of Bisfuran-Based Biopolythioureas via Multicomponent Polymerization and Its Performances as Biosorbent for Hg2+ Removal

Abstract Utilizing agro-industrial wastes/byproducts as feedstocks for functional polymers offers a promising approach to alleviating urgent resource shortages. Herein, elemental sulfur (an oil-refining byproduct) and renewable diisocyanide/diamine (agrowate derivatives) were employed as monomers to synthesize renewable polythioureas via a sustainable multicomponent polymerization (MCP) strategy, and the absorption ability of polythioureas toward mercury ions (Hg2+) was thoroughly studied. The diamine/diisocyanide monomer was prepared from the platform compound furfurylamine through a consecutive reaction. The effects of solvent and polymerization time on the molecular weight and yield of the polythioureas were systematically investigated, and ultrasonic irradiation was applied to accelerate the MCP rates. The thermal properties of polythioureas were investigated by using thermogravimetric analysis and differential scanning calorimetry. Cross-linked polythioureas were prepared through either the direct MCP or the postpolymerization modification strategy. The Hg2+ removal performances of the resulting polythioureas, including absorption kinetics, thermodynamics, mechanism, and reusability, were also studied. The polythioureas showed rapid Hg2+ absorption ability (nearly quantitative removal within 40 min) and over 99% selectivity for Hg2+ in electroplating wastewater which containing complex metal ions.