Affinity Membrane Based On Surface Glycosylation For Boron Removal

A novel affinity membrane is proposed for boron removal by microporous polypropylene membrane (MPPM) functionalized with glycopolymer containing saccharide polyols as ligands. The affinity is based on specific complexation between the saccharide ligand and boric acid. A two-step procedure was used to prepare this glycopolymer-functionalized affinity membrane. 2-Aminoethyl methacrylate hydrochloride (AEMA) was tethered on the surface and in the pores of MPPM by UV-induced graft polymerization. Grafting in the membrane pores was visualized by dying the cross-section of poly(AEMA)-grafted MPPM with fluorescein disodium and imaging with CLSM. It is reasonable to conclude that glycopolymer can also be formed both on the membrane surface and in the membrane pores by the subsequent coupling of the AEMA unit with lactobionic acid (LA). Physical and chemical properties of the affinity membrane were characterized by FESEM and FT-IR/ATR.Boron removal from water was carried out by a single piece of glycopolymer-functionalized MPPM in a dynamic filtration system, and 3-aminophenylboronic acid was chosen as a typical model boric acid. The optimun operation condition was investigated. The results show that the highest removal efficiency is 39.64%. Regeneration of this affinity membrane was easily realized through washing with 0.3 M HCl. The membrane can thus be reused without significant loss of binding capability. Furthermore, the boron removal efficiency can be improved with the aid of magnesian ion, and the highest removal efficiency is 66.01%. The glycopolymer-functionalized MPPM with glucose pendant as the ligand was also applied to remove boron from water. The results show that the glucose-immobilized MPPM can not remove boron from water as effective as the lactose-immobilized MPPM. Complexometric titrition test was also carried out to confirm the results.