Superhydrophilic photothermal adsorption material for efficient lithium extraction from seawater enhanced by synergistic effect of photovaporization and adsorption

The ocean contains abundant water and lithium resources, and extracting lithium from natural seawater is regarded as one of the most effective methods to address the shortage of lithium resources. Adsorption is a highly effective method for capturing lithium. However, traditional adsorption materials are hindered by low capacity, slow kinetics, and poor selectivity. Therefore, this paper developed a novel strategy of solar-driven for enhancing lithium-ion adsorption by synthesizing a new type of adsorbent (ACT-Li). This approach increases the temperature and lithium concentration in the micro-environment at the interface between the adsorbent and seawater, thereby improving both the lithium adsorption capacity and rate while simultaneously generating freshwater from seawater. Experimental results demonstrate that ACT-Li achieves a photothermal conversion efficiency of 97.61 % under single solar irradiation. Furthermore, light significantly increases both the diffusion rate and adsorption capacity of lithium ions, and compared to dark conditions, the adsorption capacity of lithium ions in ACT-Li increased by 35.28 %. In simulated seawater, the adsorption capacity for lithium ions can reach 31.83 mg/g, indicating strong selectivity of ACT-Li for lithium ions. The developed ACT-Li features a simple preparation process, high photothermal conversion efficiency, strong water transport capabilities, and high lithium extraction efficiency from seawater, providing a novel strategy for lithium extraction and opening new avenues for the utilization of marine resources.