Investigation on the effect of sintering temperature on kaolin hollow fibre membrane for dye filtration

Abstract

Despite its extraordinary price, ceramic membrane can still be able to surpass polymeric membrane in the applications that require high temperature and pressure conditions, as well as harsh chemical environment. In order to alleviate the high cost of ceramic material that still becomes one of the major factors that contributes to the high production cost of ceramic membrane, various attempts have been made to use low cost ceramic materials as alternatives to well-known expensive ceramic materials such as alumina, silica, and zirconia in the fabrication of ceramic membrane. Thus, local Malaysian kaolin has been chosen as the ceramic material in this study for the preparation of kaolin hollow fibre membrane since it is inexpensive and naturally abundant in Malaysia. Due to the fact that the sintering process plays a prominent role in obtaining the desired morphology, properties, and performances of prepared ceramic membrane, the aim of this work was to study the effect of different sintering temperatures applied (ranging from 1200 to 1500 °C) in the preparation of kaolin hollow fibre membrane via dry/wet phase inversion-based spinning technique and sintering process. The morphology and properties of membrane were then characterised by SEM, AFM, FTIR, XRD, and three-point bending test, while the performances of membrane were investigated by conducting water permeation and Reactive Black 5 (RB5) dye rejection tests. From the experimental results obtained, the sintering temperature of 1400 °C could be selected as the optimum sintering temperature in preparing the kaolin hollow fibre membrane with the dense sponge-like structure of separation layer that resulted in the good mechanical strength of 70 MPa with the appreciable water permeation of 75 L/h m bar and RB5 rejection of 68%.

Adsorptive Removal of Phosphate from Aqueous Solution by Magnetic-Supported Kaolinite: Characteristics, Isotherm and Kinetic Studies

“…A. A. Adeyi et al DOI: 10.4236/ojapps.2019.97043 550 Open Journal of Applied Sciencescomparison with the standard pattern of kaolin as reported by[13] [29]. In contrast, the XRD pattern of MK(Figure 1(b) revealed the presence of Fe 3 O 4 and the following peaks were observed: at 2θ = 18.60˚, 31.59˚, 35.32˚, 43.08˚, 62.39˚, corresponding to the peaks of Fe 3 O 4[17].…”

Materials and Applications for Low-Cost Ceramic Membranes

“…Kaolin (Al 2 Si 2 O 5 (OH) 4 ) is a type of widely occurring clay that has been studied as the basis of components in inorganic membranes, including support layers [17,18,19], microfiltration (MF) layers [20,21,22], and ultrafiltration (UF) layers [23]. Hubadillah et al discussed kaolin membranes in detail in their recently published review paper, focused on the fabrication and application of kaolin-based low-cost membranes [13].…”

“…Kaolin membranes without any reactive additives presented only mullite (3Al 2 O 3 ·2SiO 2 ) and cristobalite (SiO 2 ) phases following processing at temperatures higher than 1200 °C [21]. The use of yet higher temperatures further enhances mechanical strength through the formation of needle-like mullite structures, i.e., mullite whiskers, and densification of membranes [22,25]. However, it is possible to obtain different phase assemblages by including a various solid-state inorganic component with the propensity to react at high temperatures.…”

“…The mechanical strength of kaolin-based membranes is governed by porosity and mineralogy, which are determined by additives and sintering temperature. Higher sintering temperatures lead to glass formation and improved bonding between ceramic particles, producing more stable membranes [22,29,35]. Usually, high temperatures, above 1200 °C, are required to obtain mullite-rich membranes with sufficient mechanical robustness for water treatment applications, as shown in Figure 2.…”

“…However, the comparison of the mechanical strength of different membranes fabricated using kaolin, with or without additives, is rendered complex owing to the diversity of mechanical testing methods and sample geometries. For example, in many papers, three-point bending test is used [10,17,22,28,43], while in some cases, compression [21,33], biaxial flexural strength [26], and diametral compression tests are used [18,23,42]. It should be noted that, in general, while a three-point bending test is more appropriate for facilitating comparative analysis, mechanical stability tests should be designed according to the membrane shape (configuration).…”