Search

Low-cost green ceramic hollow fiber membranes (CHFM) were successfully designed and fabricated from the industrial waste ash, palm oil fuel ash (POFA) via phase inversion-based extrusion/sintering techniques for water filtration application. The extrusion process parameters such as suspension viscosity, air gap distance, and bore fluid flow rate were systematically explored to produce the membrane with desired morphology. A high suspension viscosity would result in a small macro-voids structure. Moreover, a high air gap distance would induce fiber with long macro-voids structure, while a low bore fluid flow rate would lead to the formation of distorted lumen structure. The effect of sintering temperature toward CHFM was also studied and characterized. An increase in the sintering temperature improved the membrane bending strength, but also afflicted the flux performance due to lower porosity and higher tortuosity. The developed membranes achieved excellent bending strengths of >75 MPa at lower sintering temperatures than the alternative ceramic counterparts, due to the formation of the eutectic liquid during sintering. The relatively low sintering temperature of POFA-derived CHFMs could reduce the energy consumption and sintering duration, which could be more economically attractive than their ceramic counterparts, thus benefiting industrial users. [ABSTRACT FROM AUTHOR]

The application of low cost ceramic membrane from kaolin has attracted much interest due to its excellent mechanical stability, chemical and thermal resistivity and most importantly, because it is cost effective, in some cases, compared to polymeric membranes. The advantage of kaolin based ceramic membrane is its thermal properties that allow sintering at much lower temperature than alumina. Although many studies have been made on the application of kaolin based ceramic membranes, detailed discussions were scarcely made and the information on the fabrication of ceramic membrane from kaolin is very limited. This article is aimed to make a comprehensive review on ceramic membrane from kaolin for its fabrication methods and applications. An attempt is also made to show the future direction of the R and D on the kaolin based ceramic membrane. [ABSTRACT FROM AUTHOR]

The objective of this study is to produce superhydrophilic, low cost kaolin-based ceramic hollow fibre membrane (KHFM) for efficient oily-wastewater separation. The asymmetric KHFMs with short finger-like voids were successfully prepared via a combined phase inversion and sintering technique. It was observed that the increase in sintering temperature enhanced membrane mechanical strength and promoted significant changes on membrane morphology. The combination of hydrophilic characteristic (contact angle of 33°) and small pore size (0.35 μm) of the kaolin KHFM sintered at 1500 °C resulted in excellent oily wastewater separation, with a 100% success rate, thus indicating that KHFM is able to repel most of the oil and allow only water to pass through its pores. In conclusion, the developed KHFM can be regarded as a promising medium for oily wastewater separation. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate the feasibility of using kaolin as a starting material in ceramic membrane support preparation using phase inversion/sintering technique at different kaolin content and non-solvent coagulant bath. The ceramic suspension was prepared by mixing the kaolin, polyethersulfone (PESf) as binder, N-methyl-2-pyrrolidone (NMP) as solvent and Arlacel as dispersant using a magnetic stirrer; drying and sintering process at temperature of 1200 °C. By varying the kaolin contents, different morphologies of ceramic support were obtained due to the variations in viscosity of ceramic suspensions. Similarly, different non-solvent coagulant bath was found to affect the membrane support structure through liquid–liquid demixing process and at the same time affected membrane support's roughness, porosity, pore size distribution and strength. All ceramic supports possessed high gas permeation with no separation capability, proven the suitability as ceramic membrane support. The cost for the prepared ceramic membrane support in this work is as low as $5.97, prepared at 54.0 g kaolin content and immersed into distilled water. [ABSTRACT FROM AUTHOR]

Abstract Pretreatment of produced water using ceramic membrane is considered promising due to its excellent separation performance and thermal and mechanical stabilities, however, the high cost of ceramic membranes discourages industries for large scale applications. The purpose of this work is to fabricate ceramic hollow fibre membranes from alumina-spinel composite powder synthesized from low-cost aluminium dross waste for the pretreatment of oily saline produced water. The hollow fibre membranes were prepared via phase inversion-based extrusion and sintering technique. Aluminium dross (less than 50 µm) was subjected to pre-treatment via water leaching and calcination, resulting in alumina (Al 2 O 3) and spinel (MgAl 2 O 4) as major constituents. Subsequently, the as-prepared alumina-spinel composite powder was used as a ceramic material in fabricating the hollow fibres. The effect of sintering temperatures on the morphology, crystalline phase, pore size and porosity, mechanical properties, and removal efficiencies of the alumina-spinel composite hollow fibre membranes were investigated. The microfiltration test of the hollow fibres was assessed using produced-water feed of 200 mg L−1 at 1 bar. The hollow fibre sintered at 1275 °C offers 92.41% rejection percentage of oil, the highest after 50 min of stable flux. Furthermore, turbidity was found to decrease from 378 NTU to 28.5 and 22.5 NTU for hollow fibres sintered at 1250 and 1275 °C after 2 h of filtration. In this work, the alumina-spinel composite hollow fibre membranes are found to be an effective tool as an alternative for the pretreatment of oily saline produced water. Graphical abstract fx1 [ABSTRACT FROM AUTHOR]

This work describes the preparation of green ceramic hollow fiber membranes derived from waste sugarcane bagasse ash (WSBA) using phase inversion and sintering techniques as membrane support for water filtration. The first step consisted in the production of WSBA is by the calcination process of sugarcane bagasse at 800 °C and followed characterizing of the microstructure, phases present, and thermal behavior using transmission electron microscopy (TEM), X-ray fluorescence (XRF), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and Fourier-transform infrared spectroscopy (FTIR). This process was followed by the preparation of ceramic dope suspension consisting of WSBA powder as the main material, NMP as the solvent, PESf as the binder, and Arlacel P135 as the dispersant. In this work, various spinning parameters (effect of SWBA contents, bore fluid flow rate, air gap, and sintering temperature) were evaluated. By varying these parameters, significant effects on the membrane structure and mechanical strength were observed. The different sintering temperatures resulted in wormlike pores in the membrane structure due to neck growth and melting mechanism. The preliminary performance tests show that the green ceramic hollow fiber membrane prepared with a WSBA content of 60 wt%, bore fluid flow rate of 10 mL/min, air gap of 10 cm, and sintering temperature of 1000 °C induced a stable permeate water flux (PWF) of ~ 466.2 L/m 2 h at the beginning of the filtration process. [ABSTRACT FROM AUTHOR]

Graphical abstract The present study revealed the evolution of dynamic drying variables in the hygroscopic and non-hygroscopic multi-layer ceramic structure is strongly associated to the different properties of both layer structures. A strong relationship between drying variables and the possibility of deformation or cracking in the multilayer dried body was presented by correlating the drying variables evolution in the fully coupled model with the strain mechanism. Highlights • Simulation of the convective drying for ceramic membrane multi-layer structure. • Fully coupled model of heat, mass and gas transport was proposed. • Ceramic membrane with hygroscopic at top layer and non-hygroscopic at bottom layer. • Correlation of the drying variables evolution to the cracking mechanism. Abstract In ceramic membrane preparation, the understanding of drying phenomena is very important to ensure no defects and failures that may present in the membrane layers. The combination of hygroscopic and non-hygroscopic multilayer systems that possess different properties is always associated with the failure of the consolidated structure of ceramics during the drying and sintering process. Hence, a two-dimensional mathematical model that coupled mass, heat, and gas transfer was employed to describe the drying process as a whole multilayer ceramic membranes structure. The finite element method was used to solve the model and computation was carried out using a Skyline solver to capture the highly nonlinear and transient process. This study emphasises on the evolution of transport variables during the drying that can be correlated to shrinkage mechanism. The side surface heating boundary was performed with a conclusion that hygroscopic materials have low drying rate due to the material characteristic which inherent higher water retention in a solid matrix. This characteristic also causes higher pore water pressure and gas pressure. The drying of hygroscopic layer has resulted in higher moisture gap which in turn increased the possibilities of cracking. The results obtained from this study enable the optimisation with respect to drying time and material selection thus significantly contributes to the energy saving as well as reducing the environmental effect via less waste energy loss. [ABSTRACT FROM AUTHOR]