Preparation and performance evaluation of multi-template thermo-responsive imprinted polymers for simultaneous and proportional adsorption-desorption of Ga3+, In3+, and SeO32−

The recovery of valuable elements from spent copper–indium–gallium–diselenide solar cells has been a topic of considerable interest. In this study, based on the elemental ratios in the leachate of spent solar cells, a multi-template thermos-responsive imprinted polymer (GIS-TIIP) was prepared by combining thermo-responsive technology and imprinted technology. This polymer was used for the simultaneous and proportional selective separation and purification of gallium, indium, and selenium from the leachate. The structure and performance of GIS-TIIP were systematically characterized through Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy-Energy Dispersive Spectrometry, Transmission Electron Microscopy, Brunauer-Emmett-Teller surface area and pore size analysis, Thermogravimetric Analysis, X-ray Photoelectron Spectroscopy, and Inductively Coupled Plasma-Atomic Emission Spectroscopy. The structure of GIS-TIIP responded to temperature changes. At 35 °C, maximum adsorption capacities were 0.0162 mmol/g for Ga 3+ , 0.0671 mmol/g for In 3+ , and 0.1001 mmol/g for SeO 3 2− . At 25 °C, maximum desorption ratios were 72.65 % for Ga 3+ , 75.33 % for In 3+ , and 69.34 % for SeO 3 2− . The ratio of maximum adsorption capacities for the three target ions (1: 4.142: 6.179) was close to the ratio of the molar amounts of template substances added during the synthesis (1:4:8). The adsorption process of GIS-TIIP fitted better with the pseudo-first-order kinetic model and the Langmuir model. When GIS-TIIP was applied to the diluted leaching solution, the purity of the target elements increased from 55.99 % to 80.98 % after a single adsorption/desorption cycle. The ratio of gallium, indium, and selenium was found to be 1: 4.263: 5.509, indicating the potential for alloy recovery and recycling. After 10 cycles of repeated use, GIS-TIIP still retained 75.71 % of its original adsorption capacity.