Manufacturing of tubular ceramic microfiltration membrane based on natural pozzolan for pretreatment of seawater desalination

This work describes manufacturing of low-cost tubular ceramic microfiltration membrane made from natural pozzolan. Firstly, the tubular ceramic support was prepared by extrusion technique followed by sintering at low temperature of 950 degrees C. The extruded paste is essentially composed of pozzolan powder (< 200 mu m), clay ( < 68 gm), some organic additives and water. This formulation is conducted to obtain a ceramic support with uniform porous structure and high water permeability. Secondly, the membrane layer was prepared by cross flow filtration of suspension containing the pozzolan powder ( < 45 gm), polyvinyl alcohol and water, thereafter the membrane was dried and sintered at 950 degrees C. Scanning electron microscope analysis showed that the membrane has homogenous structure and is free from any defect. In addition, the average pore size and water permeability parameters were respectively 0.36 mu m and 1444.7 L/h.m(2).bar. Manufactured membrane is expected to have challenge application in pretreatment of seawater for desalination. Membrane performance was evaluated by filtration of raw seawater in the aim of reducing its turbidity and its chemical oxygen demand. Experimental results showed a high rejection of turbidity (98.25%) as well as a good retention of chemical oxygen demand (70.77%).