DEVELOPMENT OF A CERAMIC MICRO FILTERATON MEMBRANE USING NATURALLY OCCURING CLAY AND KAOLIN BASE

Abstract

This research concentrates on the fabrication of ceramic microfiltration membranes using local clay (kaolin and bulk clay) as the raw material. The raw material was pre-processed and paste casting method was used for fabrication. Three different membranes were successfully fabricated: membrane A, membrane B and membrane C. The three ceramic microfiltration membranes of diameter 320 mm and thickness of 10 mm each which was fabricated by the paste casting method from different percentage compositions of clay, kaolin, calcium carbonate and binding agent (sodium carbonate). The fabricated membranes were sintered at 1000oC and characterized. Scanning Electron Microscopy (SEM) was conducted by optical electro machine. Fourier Transform Infra-Red Microscopy (FTIR) tests were conducted on the membranes. Water absorption, bulk density tests and porosity tests were measured by Digital Electronic Scale. Membrane A fabricated, have compositions of 38% ball clay, 38% kaolin, 23% CaCo3 and 1% binding agent (Na2So3), membrane B have compositions of 51% kaolin, 26% ball clay, 23% CaCo3 and 1% binding agent (Na2So3),membrane C have composition of 51% ball clay, 26% kaolin, 23% CaCo3 and 1% binding agent( Na2So3). It was observed that increase in the percentage composition of kaolin and decrease percentage composition of clay, the filtration rate decreased from 33.66% to 4.045% and the percentage value of porosity also decreased from 108.8% to 80%.During the firing process, the calcium carbonate (CaCo3) burns and disintegrate into calcium oxide and carbon dioxide, this leaves the system creating a system of pores within the ceramic, allowing water to flow slowly through the vessel wall and the calcium oxide enhances the ceramic stability and mechanical strength. It was also found that bulk density increased with increases in amount of kaolin in the prepared membranes, but reverse was the case in term percentage of water absorption. Body compositions containing higher amounts of kaolin showed lowest water absorption and highest strength due to better densification.SEM showed uniformly distributed pores and no cracks was seen around them. The porosity, percentage of water absorption and mechanical properties depend on the content of kaolin composition which had an effect on the membrane performance. The membrane flux was measured during experimentation and membrane C was found with the highest flux at 0.54 L/hr.m2, while membrane A has flux output of 0.47 L/hr.m2 and membrane C flux output was recorded to be the lowest at 0.35 L/hr.m2. A removal efficiency of 92% was observed with membrane Ain removal of Cu, Fe removal efficiency of membrane A was 88%, Pb removal efficiency of membrane A was 84%, while 100% removal efficiency of Ni was recorded in membrane A heavy metal removal studies. Membrane B and membrane C removal efficiency was also recorded at different heavy metals removal percentage. The performance of the membrane was reasonably well in the physico-chemical analysis carried out. All the membranes were studied for their regeneration and reusability.