화학공학소재연구정보센터
Journal of Membrane Science, Vol.510, 112-121, 2016
Synthesis of hyperbranched polymers towards efficient boron reclamation via a hybrid ultrafiltration process
Two hyperbranched polymers, hyperbranched polyglycidol (HPG) and 2, 3-Dihydroxypropyl-hyperbranched polyethylenimine (Diol-HPEI), were synthesized and studied as polychelatogens for boron reclamation via a hybrid ultrafiltration process, with the objectives of evaluating the key factors for polymer-boron chelation and improving boron rejection efficiency. Their chemical structures were unveiled by FTIR and XPS analyses whilst molecular weights were carefully tailored in order to be fully retained by a commercial ultrafiltration (UF) membrane. The chelation capacity of the two polymers was compared under different operating conditions i.e., chelating temperature, polymer loading and pH. It appears that Diol-HPEI prominently outperforms HPG because the tertiary amine group may be more competent than the ether group in terms of their protonation capability. Eventually, a rejection of 66-91% was achieved with a Diol-HPEI polymer loading of 100 g per g boron in the pH range of 6.9-9.0. Besides, the effects of interfering ions, i.e., Na+, Mg2+, Cl- and SO42- on polymer-boron interactions were examined in the Diol-HPEI/boron solution at the neutral condition. Results reveal that divalent cations may exert more negative influence on boron rejection owing to the competition between them and boron to form complexes with chelating polymers. These findings may provide useful insights in design of efficient boron-chelating polymers. (C) 2016 Elsevier B.V. All rights reserved.