在聚砜微滤膜表面接枝聚合叔胺单体DMAEMA及接枝膜对水介质中毒性阴离子的吸附与分离特性

Graft-Polymerization of Tertiary Amine Monomer DMAEMA on Micro-Filtration Membrane and Adsorption and Separation Characteristics of Grafted Membrane for Toxic Anions in Water

采用相转化法制得了氯甲基化聚砜(CMPSF)微孔滤膜,以乙二胺为试剂对CMPSF膜进行化学改性,膜表面的伯胺基与水溶液中的过硫酸铵构成表面引发体系-NH_2/S_2O_8^(2-),使叔胺单体甲基丙烯酸二甲基氨基乙酯(DMAEMA)发生接枝聚合,获得了多孔接枝膜PSF-g-PDMAEMA。考察了接枝聚合的规律,对接枝膜进行了充分表征,考察研究了接枝膜对2种毒性阴离子CrO_4^(2-)及MoO_4^(2-)离子的吸附性能和膜分离去除行为。研究结果表明,控制水溶液中过硫酸铵的质量分数为1%,温度为50℃,可制得PDMAEMA接枝度为0.64 mg/cm^2的接枝膜。在酸性及中性水溶液中,凭借强烈的静电相互作用,多孔接枝膜PSF-g-PDMAEMA对毒性阴离子CrO_4^(2-)离子及MoO_4^(2-)离子均会产生强吸附作用;以该多孔接枝膜为滤膜进行膜分离过程,通过选择性吸附,可有效地去除水介质中的CrO_4^(2-)离子。

Micro-filtration membrane of chloromethylated polysulfone （CMPSF） was first prepared by phase inversion method, and then CMPSF membrane was chemically modified with ethidene diamine. A surface-initiated system -NH2/S2O8^2- was constituted by using the primary amino group on the membrane surface and the ammonium persulfate in the aqueous solution, and the tertiary amine monomer N, N-dimethylaminoethyl methacrylate（DMAEMA） was made to produce graft-polymerization, resulting in the porous grafted membrane PSF- g-PDMAEMA. The effects of the main factors on the graft-polymerization, were examined, and the grafted membrane was fully characterized. The adsorption abilities of the grafted membrane for two toxic anions, chromate and molybdate, were examined, and the membrane separation and removal behavior of the grafted membrane for CrO4^2- ion was studied. The experimental results show that the grafted membrane PSF-g-PDMAEMA with a grafted degree of 0.64 mg/cm2 of PDMAEMA can be obtained by controlling the concentration of ammonium persulfate as 1% and the reaction tempera.ture at 50 ℃. In acidic and neutral solution, by right of the strong electrostatic interaction, the grafted membrane PSF-g-PDMAEMA has strong adsorption ability for CIO4^2- and MoO4^2- anions. As the membrane separation process is carried out by using the grafted membrane PSF-g- PDMAEMA as filter membrane, CrO4^2- ion in water can be effectively removed by selective adsorption.