Preparation of inorganic supports for liquid waste treatment

The ceramic products are extremely interesting in the field of the membrane supports because of their mechanical resistance, chemical inertia, long working life and thermal stability. Research is currently directed towards the exploitation of materials at a lower cost. The purpose of this work is the development of microporous ceramic materials based on clay for liquid waste processing. Tests of filtration of saccharose solutions (10−2 M), sodium chloride (10−2 M) and Evans blue solutions (10−4 M) were performed on membane supports, which were synthesized starting from a natural local barbotine consisting of clay (21%), various kaoline kinds (35%), feldspath (20%) and finally sand (24%). Four different tubular membrane supports were prepared by mixing barbotine with activated carbon (1%), then barbotine with alumina-γ (3%) and finally with oxide titanium “anatase variety” (3%). The supports were thermally treated at a heating rate of 10 °C/h up to 1100 °C. Volumes of 5 L of the various solutions were filtered tangentially for 3 h under an applied pressure of 3.5 bar. The study of the liquid filtration and flow through these supports showed that the retention rate depends on support composition and pore diameter, and solute molecular weight. The anatase containing support gave a 70% retention rate for blue Evans and flux of 33 L/m2 h, while the double layer support resulted in 98% retention rate and a flux of 8 L/m2 h for the same solution. The maximum retention rate obtained varied from 50% for saccharose solution with barbotine and anatase containing supports to 98% for Evans blue solution.