Carboxyl and amino acid functionalized indole-based polymer for ultrafast uranium extraction in aqueous solution

High-efficient and fast extraction of uranium is of great significance not only for environmental remediation, but also meeting the shortage of uranium storage. A novel type of porous indole-based polymer (PHTPIAAs) decorating with amino acid and carboxyl groups was fabricated by a simple Friedel-Crafts acylation reaction. The as-prepared PHTPIAAs possessed encouraging and effective elimination properties for uranium in aqueous solution by taking advantages of the cooperativity of cation-p interaction and complexation. The experimental results showed that the PHTPIAA-2 exhibited ultrafast uptake rate (50.0 min) to uranium with a high removal efficiency of 97.2%, and the maximal uptake capacity was up to 457 mg g(-1) calculated by Langmuir model at 298 K. The regeneration of PHTPIAA-2 was fulfilled expediently with hydrochloric acid (HCl, 0.1 mol L-1) as eluant, and the removal efficiency of the reborn PHTPIAA-2 maintained 80.2% after 5 cycles. These findings demonstrated that this new indole-based polymer could be considered as a valuable material in the extraction and recovery of uranium from various uranium-containing aqueous solutions.