Prevention of Membrane Fouling Using Electric Pulse in Dead End Microfiltration of Titanium Suspensions

Abstract

Denyutan elektrik merupakan salah satu kaedah yang berkesan untuk menyingkirkan bahan–bahan endapan pada permukaan membran polimerik dan mampu mencegah permukaan daripada tersumbat. Hasil–hasil dapatan uji kaji pencegahan permukaan membran dari tersumbat menggunakan denyutan elektrik bagi proses penurasan mikroampaian titanium dibentangkan. Kesan beberapa pembolehubah proses seperti selang masa antara denyutan elektrik, jangkamasa sesuatu denyutan elektrik, pH larutan, kekuatan ionik bagi elektrolit dan kekuatan voltan sesuatu denyutan elektrik telah dikaji dari segi prestasi dan keberkesanannya dalam mencegah membran dari tersumbat. Didapati bahawa fluks meningkat secara ketara dengan adanya pergerakan elekroforetik butiran bahan endapan menjauhi permukaan membran dan berlakunya proses elektroosmosis di dalam bahan endapan itu sendiri. Keputusan–keputusan telah dianalisis dari segi purata fluks, purata kepekatan bahan endapan, peratus purata perolehan semula bahan endapan dan peratus perolehan semula air. Didapati bahawa sifat fizikal dan kimia larutan (pH dan kekuatan ionik elektrolit) memberi kesan yang besar ke atas kaedah pencegahan permukaan membran dari tersumbat. Ampaian titanium pada pH 8 dan dengan kekuatan ionik elektrolit 0.01M memberi prestasi terbaik dalam pembersihan permukaan membran. Selang masa antara dua denyutan yang singkat dan jangkamasa 10 saat sesuatu denyutan dengan kekutan voltan 100V merupakan keadaan optimum bagi denyutan elektrik untuk menyingkirkan bahan–bahan endapan dari permukaan membran menggunakan denyutan elektrik. Kata kunci: pemisahan membran; penurasan mikro; membran tersumbat; denyutan elektrik;titanium dioksida. Electric pulse in an effective means of removing particulate materials from polymeric membrane and preventing the membrane fouling. The experimental results for dead end microfiltration of titanium suspension to prevent membrane fouling using electric pulses are presented. The effect of processing variables such as the pulse interval, pulse duration, pH of the solution, ionic strength of the electrolyte and the strength of the applied voltage for dead end microfiltration of titanium suspensions were studied on the performance and effectiveness of this prevention of membrane fouling. The flux was significantly increased by both electrophoretic motion of particles away from the membrane surface and electroosmosis occurring in the filtercake. The results were analyzed for its average flux, average cake concentration, average percentage recovery of cake and average percentage recovery of water. It is found that the physical and chemical properties of the solution (pH and ionic strength of the electrolyte) have a great effect on this membrane fouling prevention method. Titanium suspension at pH 8 and ionic strength of 0.01M electrolyte strength gave the best membrane cleaning performance. Shorter pulse interval with 10 seconds pulse duration with 100V applied voltage were the optimum conditions to remove the filtercake from the membrane surface. Key words: membrane separation; microfiltration; membrane fouling; electric pulses; titanium dioxide