Synthesis of N-methylglucamine modified macroporous poly(GMA-co-TRIM) and its performance as a boron sorbent

A chelating polymeric sorbent was developed by functionalizing poly(glycidyl methacrylate-co-trimethylolpropane trimethacrylate), poly(GMA-co-TRIM), with N-methylglucamine (MG) via a simple post-grafting route. The resulting well-defined millimeter-sized spheres of poly(GMA-co-TRIM)-MG had permanent macropore structures and low swelling degree, with accessible ligands of 1.84 mmol/g. The boron adsorption behavior of the sorbent was studied in batch mode by varying different parameters like the pH value, the initial concentration of boron and the adsorption time under noncompetitive conditions. It was found that the sorbent always maintained the high capacity between pH 2.6 and 8.6, in which the optimum pH was 7.5. The adsorption behavior of the sorbent obeyed the Langmuir isotherm well. The adsorption capacity of the sorbent for boron was in the same level as that of a commercially available N-methylglucamine-type polystyrene resin. However, it adsorbed boron more quickly. The sorbent also showed good durability and reusability through the fixed-bed adsorption tests. The study on the separation of boron from brine of salt lake showed a high selectivity of the sorbent, though the capacity for boron decreased due to the interference of diverse ions in brine.