Multi-carboxylic magnetic gel from hyperbranched polyglycerol formed by thiol-ene photopolymerization for efficient and selective adsorption of methylene blue and methyl violet dyes.

Synthesis of adsorbents that simultaneously possess high adsorption performance and convenient separation characteristic remains a big challenge. Herein, we report a viable strategy to prepare hyperbranched polyglycerol (HPG)-based multi-carboxylic magnetic gel (MMG) based on the thiol-ene click chemistry. The obtained HPG-based MMG adsorbent with porous structure and multiple carboxylic groups not only exhibited fast adsorption rate, superior adsorption capacity, and favorable adsorption selectivity towards cationic dyes (e.g., methylene blue (MB) and methyl violet (MV)) but also presented convenient magnetic separation characteristic. The adsorption data showed nice correlation with pseudo-second-order kinetic model and Langmuir isotherm. The optimal adsorption capacity of HPG-based MMG for MB and MV can reach as high as 458.7 and 400.0 mg g-1, respectively. Moreover, the dye-adsorbed HPG-based MMG could be regenerated in ethanol for reuse without obvious decline of removal efficiency. On the basis of the superior adsorption property of HPG-based MMG, this work offers an effective strategy to prepare advanced adsorbent for dye removal from wastewater.