膜過濾技術是一個可以處理大量廢水的處理技術,但是其高能耗是一個待解決的重要瓶頸。在本研究中,我們嘗試以檸檬酸改質纖維素濾紙,透過Donnan效應製備一低能耗過濾系統。實驗結果顯示,檸檬酸改質濾紙在1 ppm鈷離子錯流條件下,在100 L/m2h通量下仍可以維持95%的去除率。這是因為改質過程中在膜表面引入高親和力的Lewis酸吸附位置,並透過在這些吸附位置所建立的Donnan效益達到去除鈷離子的結果。後續的實驗數據發現,儘管檸檬酸改質膜具有優越的鈷離子去除效果,但會因為不可避免的表面濃度極化現象降低其鈷離子去除效率,因此現階段僅適合處理低濃度的鈷離子廢水,其穩定性是值得後續努力的方向。
Membrane filtration is a promising water treatment technique, but its high energy consumption hinders its universal application. We herein introduce a low energy consumption filtration system, in which the cobalt rejection rate is greatly enhanced through Donnan exclusion from 10% to 95%. This is achieved by grafting citric acid onto the cellulose filter paper through esterification. The incorporated acid sites exhibits high cobalt affinity which enhances the Donnan exclusion effect. Most importantly, the filtration was conducted at atmospheric pressure yet still achieving permeate flux of 100 L/m2h. In conclusion, we demonstrate a new low energy consumption filtration system with high cobalt rejection through Donnan exclusion effect, which may have promising potential in various heavy metal contaminated waters.