Solution-processable polymers of intrinsic microporosity for selective silver removal from aqueous solution and subsequent disinfection by silver-laden coatings

Abstract

Silver ions (Ag+) in waterways pose a growing threat to the environment and living organisms. Achieving an effective and green process for Ag+ removal requires an adsorbent with excellent specificity for silver ions and easy recoverability after fouling or blocking. However, this remains a major challenge. To address this concern, we developed a high-performance adsorbent by grafting polymers of intrinsic microporosity (PIM) with thioamide groups. This thioamide-modified PIM (TPIM-1) adsorbent exhibited an exceptional adsorption capacity of 656 mg g−1 and high selectivity (distribution coefficient of 833.3 mL g−1, selectivity coefficient of 346 over Cd2+) for aqueous Ag+ removal. TPIM-1 also features good solubility in selected solvents, allowing regeneration through a dissolution separation precipitation (DSP) procedure once fouling or blocking occurs. Over 80 % of the adsorption capacity was recovered after nine continuous regeneration cycles, showcasing potential cost-effective reusability. Density Functional Theory (DFT) results reveal that the grafted thioamide groups play a critical role in selective Ag+ adsorption, with a binding energy of 54 kcal mol−1. In addition, the Ag+-loaded PIM-coated glass surface showed excellent antibacterial ability, inhibiting the growth of Bacillus subtilis and E. coli. This study provides a viable strategy for the development of a low-carbon footprint silver removing adsorbent from wastewater.