Crown Ethers “clicked” on Fibrous Polyglycidyl Methacrylate for Selective Li+ Retrieval from Aqueous Sources

Increase in lithium (Li) demand has motivated the development of simple yet very effective materials for its recovery from aqueous resources. In this work, a microfibrous (MF) composite Li+ adsorbent tethered with dibenzo-14-crown-ether-4 (DB14CE4) as ligand was successfully fabricated. Polyglycidyl methacrylate (PGMA) was electrospun as MF support, rich with epoxy groups as reactive sites for DB14CE4 functionalization. PGMA MF was subsequently azidated (N-3-PGMA) and covalently attached with alkyne terminated DB14CE4 (PPL-DB14CE4) via azide-alkyne cyclo-addition "click" chemistry. Characterization results confirm successful preparation of the final adsorbent DB14CE/PGMA MF. The Li+ adsorption mechanism is well described by Redlich-Peterson, Hill (n(H) similar to 1) and Langmuir isotherm models with capacity q(m) similar to 12.45 mg g(-1). The Li+ uptake rate follows a pseudo-second order model. DB14CE4/PGMA MF preferentially captures Li+ in different aqueous sources (seawater, simulated rubber wastewater, simulated leachates from coal fly ash and lithium-ion battery waste). Li+ uptakes ranged q(e) similar to 345-1428 mu mol g(-1) against competing ions (Na+, K+, Ba2+, Mg2+, Ca2+ Zn2+, Co2+, Cu2+, Al-3(+)) having q(e) values < 16 mu mol g(-1). DB14CE4/PGMA MF is regenerable and highly stable with consistent performance in cycled adsorption/desorption runs. Overall results demonstrate the reliability of DB14CE4/PGMA MF for selective Li+ mining in complex aqueous sources.