表面改質之醋酸纖維素微孔濾膜吸附廢水中之二價銅離子

Surface Functionalization of Cellulose Acetate Microfiltration Membranes for Sorption of Cupric Ion from Wastewater

本研究之目的係利用表面改質之醋酸纖維素微孔濾膜吸附廢水中之二價銅離子。濾膜表面改質係將能與二價銅離子產生螯合鍵結反應之肟基，引入醋酸纖維素濾膜表面結構，以吸附廢水中之二價銅離子。本研究使用之表面改質反應包括鹼性水解、過碘酸根氧化與席夫置換三個化學反應，將醋酸纖維素濾膜表面結構之部份雙羥基與乙醯基轉換成為肟基。表面改質反應造成濾膜官能基之含量變化並經化學定量與反應動力學分析，估計經過表面改質之濾膜單位面積之肟基含量為7.8 × 10-7 mol/cm2。平衡吸附實驗結果顯示，對於濃度50 mg/L 之二價銅離子酸性廢水，經表面改質之濾膜單位面積吸附之二價銅離子平均重量為0.082 mg/cm2；單位重量之濾膜吸附之二價銅離子平均重量為12.4 mg/g。

The objective of the present study is to utilize a surface-functionalizedcellulose acetate microfiltration membrane to remove cupric ion fromwastewater. The surface functionalization of the cellulose acetatemembrane was achieved by chemically transforming the membrane surfacefunctional groups into oxime groups capable of chelating cupric ion.Three reactions were employed for the surface functionalization includingalkaline hydrolysis, periodate oxidation, and Schiff’s replacement reactions.The variations in the functional groups of the membrane due to the threereactions were quantified chemically and analyzed kinetically. Theaverage amount of oxime groups after the surface functionalization wasestimated to be 7.8 × 10-7 mol/cm2 of the membrane area. By performing equilibrium sorption experiments for acidic wastewater having a cupric ionconcentration of 50 mg/L, it was found that the membrane is capable ofcollecting cupric ion 0.082 mg/cm2 of the membrane area, corresponding to12.4 mg/g of the membrane weight.