Synthesis of multicarboxylic hyperbranched polyglycerol (HPG) modified monodisperse superparamagnetic poly (glycidyl methacrylate) microspheres for capable dye adsorption
摘要
Monodisperse superparamagnetic poly (glycidyl methacrylate) microspheres (PGMA-HPG-COOH) with carboxyl group were synthesized and applied to treatment of cationic dyes wastewater. The composite adsorbent not only has good adsorption selectivity for cationic dyes (e.g., methylene blue (MB) and rhodamine 6G (R6G)), but also has convenient magnetic separation characteristics. The optimal pH for the adsorption of methylene blue was determined as pH 7, which was associated with the surface charge of adsorbent. Due to its ultra-high hydrophilicity, PGMA-HPG-COOH demonstrated a remarkably rapid adsorption rate for MB and R6G, and the adsorption saturation level of 95% can be achieved within just 10 min. The adsorption data showed nice correlation with pseudo-second-order kinetic model and Langmuir isotherm. The theoretical maximum adsorption capacity of PGMA-HPG-COOH for MB and R6G can reach 238.1 mg/g and 227.27 mg/g, respectively. Futhermore, PGMA-HPG-COOH can be effectively regenerated using a binary HCl-ethanol solution, maintaining the adsorption efficiency of 91.7% after five cycles of recycling. These findings substantiate the promising potential of the PGMA-HPG-COOH adsorbent for application in water treatment processes.