Preparation and characterization of membrane supports for microfiltration and ultrafiltration using kaolin (DD2) and CaCO₃

Abstract

A B S T R A C TThe 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. This work is mainly focussed on ceramic supports rather than its deposited membranes because it constitutes about 99% of the filter mass. Therefore, replacing the more expensive starting materials (Al 2 O 3 ) by other low cost raw materials (kaolin and calcite) for supports fabrication is significantly important. Consequently, the supports for microfiltration (MF), ultrafiltration, and nanofiltration were prepared with local kaolin (DD2) and calcite mixtures. The choice of these raw materials is based on their natural abundance (low price). These supports were made by extrusion technique order to obtain tubular supports which were afterward sintered at 1,150˚C for 2 h. It has been found that supports had interesting characteristics; an average pore size of about 4 μm, a porosity ratio around 50.5%, and a three-point flexural strength ≈28 MPa. Moreover, the pore size distribution was almost mono-modal type. The surface and the cross-section morphologies observed through a scanning electron microscope were also homogeneous and do not present any possible macro defects (cracks, etc.) These supports were selected to be substrates for the membrane layers used in MF.

Effect of kaolin particle size and loading on the characteristics of kaolin ceramic support prepared via phase inversion technique

“…Related to this work, Harabi and co-workers [37][38][39][40][41][42][43][44][45][46][47][48] have investigated most of the ceramic support fabrication from kaolin and reported mechanical strength value and porosity. Based on the Table 3 Gas permeation performance of kaolin ceramic support at different kaolin particle sizes and contents.…”

Study of Ceramic Membrane from Naturally Occurring-Kaolin Clays for Microfiltration Applications

“…This technique relies on the penetration of mercury into a membrane's pores under pressure [21,23,37]. The intrusion volume is recorded as a function of the applied pressure and then the pore size was determined.…”

“…Recently, the development of low cost ceramic membranes based on natural materials such as apatite powder [13], natural raw clay [14][15][16], graphite [17], phosphates [18,19], dolomite, kaolin [20][21][22][23][24] and waste materials such as fly ash [25][26][27][28][29], appeared as an efficient solution to treat waste water at a low cost. The properties of the ceramic membranes are mainly determined by their composition, the pore-former content and the sintering temperature.…”

Development and characterization of tubular composite ceramic membranes using natural alumino-silicates for microfiltration applications

“…Algeria is one of the countries in the world that have abundantly available raw materials, such as calcium carbonates (CaCO 3 )(CC), dolomite (CaCO 3 ·MgCO 3 ), bones (natural derived hydroxyapatite (HA): Ca 10 (PO 4 ) 6 (OH) 2 ), kaolin, feldspar and quartz. Many works have already been published for valorizing these native raw materials, for the production of advanced ceramics [1][2][3][4][5][6][7], ceramic membranes [8][9][10][11][12][13][14][15][16][17][18][19] and bioceramics [20][21][22][23][24][25][26][27]. In particular, in the membrane field the possibility of replacing the more expensive starting materials by cheaper raw materials to be used as a support (which constitutes about 99% of the filter mass) is significantly important from economic and energetic points of view.…”

“…Several materials are usually employed for the preparation of ceramics membranes, such as alumina, zirconia and titania. However, natural raw materials, such as kaolin (chemical structure: [57,58] are more and more used for preparing porous ceramics membranes [9][10][11][12][59][60][61][62][63][64][65][66][67][68] and it has been used in this work as a starting material.…”