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Performance of Annealed Polyacrylonitrile Nanofiltration Membrane  

Lee Kew-Ho (Membrane and Separation Research Center, Korea Research Institute of Chemical Technology)
Kim In-Chul (Membrane and Separation Research Center, Korea Research Institute of Chemical Technology)
Publication Information
Membrane Journal / v.15, no.1, 2005 , pp. 15-21 More about this Journal
Abstract
The integrally skinned asymmetric PAN ultrafiltration membranes were annealed for reducing the pore size. The effect of the chemical structure of two PAN polymers (homo- and copolymer) on annealing was investigated. The annealing of PAN polymer was strongly affected by the chemical structure of the polymer. In other words, the annealing effect of the copolymer was much larger than that of the homopolymer due to its less rigid structure of the main chain. Before annealing, the membranes were usually preheated in water in terms of the complete removal of remained solvents in the membranes. The annealing effect was bigger when no preheating. However, the preheating of the membrane before annealing at high temperatures leads to an increase in the pore size of membranes. The surface of the membranes was slightly negative and the salt rejection of PAN nanofiltration membrane was in the following order: R(Na₂SO₄) > R(NaCl) > R(MgSO₄) > R(CaCl₂). This salt rejection behavior could be explained by the Donnan equilibrium and the electroneutrality.
Keywords
annealing; polyacrylonitrile; copolymer; nanofiltration; Donnan equilibrium;
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