Immobilization of Ion-imprinted Polymers on Biochar for Selective Lithium Ion Recovery

The growing demand for lithium-ion batteries emphasises the critical importance of sustainable extraction and recycling of lithium resources. In this work, biomass-derived biochar was employed as a support for lithium ion–imprinted polymers (Li-IPs) immobilized through surface imprinting polymerization. Prior to polymerization, biochar was activated using K2CO3 (K2CO3 : biochar mass ratio 1:2, 1:1, 2:1) at activation temperatures of 800 and 900°C. The Li-IPs were prepared with LiNO3 (template), α-methacrylic acid (functional monomer), dibenzo-14-crown-4 (chelating agent), and ethylene glycol dimethacrylate/2,2′-azobisisobutyronitrile as the initiator and cross-linker, respectively. exhibited a time-dependent behavior and was significantly affected by the solution pH. The maximum adsorption capacities (Qmax) at pH 6.0, determined using the Langmuir isotherm model, were 0.343, 0.399, and 0.569 mg/g for WC-KL, WC-800-1-KL, and WC-900-1-KL. The obtained results indicate that biochar can function as an effective support for Li-IPs in the recovery of lithium from aqueous solutions.