Abstract: Poly(arylene ether ketone)s with carboxylic groups (PAEK-COOH) is a good membrane fabrication material, a kind of polyacids, while polyethylenimine (PEI) is a weak organic base, a kind of polybases. Those polyacids and polybases would form ionic complexation at the interface of two liquid phases. In this paper, PAEK-COOH/N-methyl pyrrolidone (NMP)/1,4-dioxane (DO) mixture, employed as polymer casting solution and aqueous solution of PEI, used as coagulation bath, respectively. Then ion complexation induced phase inversion process is applied to prepare positively charged nanofiltration membrane with thinner but denser separation skin layer. The complexing reaction at the interface of two liquid phases has great influence on the kinetic aspects of phase inversion process, which in accordance would affect the morphology and performance of the membrane. The obtained membrane, fabricated via the ion complexation induced phase inversion method, is positively charged, has high water permeability, and possesses high rejection towards divalent cations, such as Mg²⁺, Ca²⁺, Pb²⁺ etc., which could be used for removal of heavy metals from polluted water. At the optimal condition, the pure water flux of the PAEK-COOH-PEI nanofiltration membrane is 24.3 L·m-2·h^-1, with MgCl₂ rejection of 92.2%.

Key words: Polyelectrolyte complex, Carboxylated polymer, Polyethylenimine, Nanofiltration, Water purification

摘要： Poly(arylene ether ketone)s with carboxylic groups (PAEK-COOH) is a good membrane fabrication material, a kind of polyacids, while polyethylenimine (PEI) is a weak organic base, a kind of polybases. Those polyacids and polybases would form ionic complexation at the interface of two liquid phases. In this paper, PAEK-COOH/N-methyl pyrrolidone (NMP)/1,4-dioxane (DO) mixture, employed as polymer casting solution and aqueous solution of PEI, used as coagulation bath, respectively. Then ion complexation induced phase inversion process is applied to prepare positively charged nanofiltration membrane with thinner but denser separation skin layer. The complexing reaction at the interface of two liquid phases has great influence on the kinetic aspects of phase inversion process, which in accordance would affect the morphology and performance of the membrane. The obtained membrane, fabricated via the ion complexation induced phase inversion method, is positively charged, has high water permeability, and possesses high rejection towards divalent cations, such as Mg²⁺, Ca²⁺, Pb²⁺ etc., which could be used for removal of heavy metals from polluted water. At the optimal condition, the pure water flux of the PAEK-COOH-PEI nanofiltration membrane is 24.3 L·m-2·h^-1, with MgCl₂ rejection of 92.2%.

关键词: Polyelectrolyte complex, Carboxylated polymer, Polyethylenimine, Nanofiltration, Water purification