Comparative boron removal performance of monodisperse-porous particles with molecular brushes via "click chemistry" and direct coupling

A new sorbent based on micron-size, monodisperse-porous particles is proposed for boron removal by a hybrid process involving "adsorption" and "membrane separation". In the synthesis of sorbent, a multi-stage polymerization protocol involving the production of monodisperse polymer particles and the generation of dextran based molecular brushes on the particles via "click chemistry" was followed. The monodisperse porous poly(glycidyl methacrylate-co-ethylene dimethacrylate), poly(GMA-co-EDM), particles 6 mu m in size were obtained by "modified seeded polymerization". Dextran was attached onto the particles via "click chemistry". In this derivatization, the azide groups were obtained on the particles by the reaction between NaN3 and the epoxypropyl functionality. An alkyne carrying ligand, propiolic acid was covalently linked to the dextran via activation with a water soluble carbodiimide. The molecular brushes on the particle surface were then obtained by clicking alkyne modified-dextran onto the azide functionalized particles. A second sorbent was synthesized by the direct covalent attachment of dextran onto the poly(GMA-co-EDM), particles. Boron sorption capacities of both sorbents were investigated using model boron solutions and compared with the commercial resins. Monodisperse-porous particles with dextran based molecular brushes can be used for boron-removal from water. (C) 2010 Elsevier B.V. All rights reserved.