K(Ⅰ)离子印迹双极膜的制备及对海水中钾的富集

Preparation of Potassium( Ⅰ) Ion Imprinted Bipolar Membrane and the Accumulation towards Potassium from Seawater

以羧甲基纤维素钠（CM C）为功能单体,K N O3为模板分子,18-冠醚-6（18-C-6）为致孔剂,去除模板离子（K（C））后制备了钾离子印迹膜层（K-IIM）.以戊二醛（G A）改性壳聚糖（CS）得到阴膜液,将阴膜液流延于上述K-IIM上形成了K（C）离子印迹双极膜（K-IIBPM）.采用扫描电镜（SEM）观察了K-IIBPM的形貌.K-IIM具有沟壑状的孔穴结构,孔穴半径约为0.130~0.170 nm,与K（C）的半径（0.137~0.164 nm）和形状相匹配,且具有规则性;经戊二醛改性后的阴膜层具有不规则的粗糙纹理.采用已循环使用十次的K-IIBPM富集海水中的钾,当海水中N a：K：Ca：M g的质量浓度（g L-1）比为10.70：0.41：0.42：1.32,压力差为0.03 M Pa,渗透时间为60 m in时,K（C）的透过率高达96%,其它被分离离子的截留率均在85%以上,从而实现富集海水中钾的目的.

Using sodium carboxymethyl cellulose （CMC） as the functional monomer, KNO3 as the template molecule, 18-C-6 as porogen, the potassium ion-imprinted membrane （K-IIM） layer was prepared after the template ion （ K（ Ⅰ ） ） was removed. Chitosan （CS） modified by glutaralde- hyde （GA） as an anionic membrane solution was cast on the K-IIM to form potassium ion-imprinted bipolar membrane （ K （ Ⅰ ） -IIBPM）. The morphology of K （Ⅰ） -IIBPM was observed by scanning electron microscopy （SEM）. The K-IIM layer had a gully shape cavity structure, the cavity radius was about 0. 130 - 0. 170 nm, which matched with the size and shape of K （ ionic radiu was 0. 137 -0. 164 nm） and had a regularity. Cation layer modified by GA had a rough irregular texture. The K（ Ⅰ ）-IIBPM recycled ten times was applied in enriching potassium from the seawater, when the mass concentration （g · L^-1） of Na： K： Ca： Mg was 10. 70： 0. 41： 0. 42：1.32 in seawater; the pressure difference was 0. 03 MPa; the penetration time was 60 minutes, the penetration rate of potassium ion was up to 96% ; the retention rate of other separated ions were above 85%, thus, which achieved the purpose of enriching potassium from the seawater.