Solvothermal Preparation of Microporous Polyureas for Au(III) Adsorption

The enrichment and recovery of gold from wastewater are an alternative method to obtain this noble metal, which benefits reducing hazardous emissions from the conventional ore mining process and reserving natural gold for sustainable development. Inspired by our previous work (Lei et al., Macromol. Rapid Comm. 2022, 2200712), four families of microporous polyureas (mPPUs) with a large surface area (690 m² g^-1) and abundant heteroatom sites have been prepared via the factor-optimized solvothermal protocol. The resultant sample NPU-A starting from 1,5-naphthalene diisocyanate (NDI) and tri(4-aminophenyl) amine (TAPA) exhibits the maximum Au(III) adsorption capacity of 1300 mg g^-1 and high selectivity even when the Au(III) concentration is as low as 0.1 mg L^-1. This study not only demonstrates the robustness of the high-throughput synthetic strategy but also promotes the investigation of the structure-activity correlation between the mPPU chemical structure and Au(III) adsorption performance.