Crescent-shaped micromotor sorbents with sulfonic acid functionalized convex surface: The synthesis by A Janus emulsion strategy and adsorption for Li+

Self-propelled micromotor (SPM) plays a vital role in recycling of lithium (Li + ) from wastewater in battery industry. In this work, a crescent-shaped micromotor sorbent (CSMSs) with sulfonic group on convex surface was prepared by Janus emulsion to extract Li + . Using sodium p-styrene sulfonate as a functional monomer , well-designed CSMSs was prepared by UV-induced monomer interfacial polymerization, and their pit size can be controlled by adjusting the ratio of two incompatible oils (ethoxylated trimethylolpropane triacrylate and liquid paraffin). In addition, MnO 2 nanoparticles , which embedded into concave interface, generated O 2 bubbles in the presence of H 2 O 2 , and constant circular or line motion of CSMSs was observed. Zeta potential of CSMSs was −51.66 eV at pH = 10, and strong electrostatic attraction between sulfonate groups and Li + endowed the maximum monolayer adsorption capacity of 31 mg g −1 at 25 °C. Self-propelled effect further enhanced kinetic performance for Li + , and equilibrium time can be reduced from original 10–6.0 h, suggesting autonomous movement achieves rapid mixing and mass transportation. After three adsorption/desorption cycles, the adsorption capacity of the material remains above 90%. This simple and large-scale preparation strategy provided a synthetic method for functional and Janus SPM, as well as sorbents for Li + enrichment.