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A new application of green ceramic hollow fiber membrane (CHFM) derived from rice husk ash (RHA) for efficient heavy metals removal has been developed. A common and advanced fabrication method, i.e. combined phase inversion and sintering technique was used to produce the membrane with high flux. Thereby, the membrane can effectively act, as both adsorbent and separator for heavy metals in single-step process with high separation efficiency up to 99% removal of zinc [Zn(II)], lead [Pb(II)] and nickel [Ni(II)]. The kinetic data of these heavy metals show the best fit for pseudo-first order for Ni (II) [R 2 =0.981] and intraparticle diffusion kinetic model for Zn (II) [R 2 =0.913] and Pb (II) [R 2 =0.914]. Thus, this study convinced that the ceramic membrane from waste rice husk ash proved to be an attractive, effective and environmentally friendly both adsorbent and separator for heavy metals removal from aqueous solution. [ABSTRACT FROM AUTHOR]

Ceramic hollow fibre membranes (CHFMs) are known to have superior characteristics including excellent thermal, mechanical, and chemical stability. Major limitations include their high cost and brittleness, traits which have hindered the commercial adoption of this technology. This paper studies the effects of three main fabrication parameters, i.e. ceramic content, bore fluid flowrate, and sintering temperature, on morphology and mechanical strength of low-cost CHFM from a well-known material in producing high strength concrete, i.e. metakaolin. The novel CHFM from metakaolin was prepared via a combined phase inversion and sintering technique. Scanning electron microscopy (SEM) and three-point bending strength were employed to examine the hollow fibre's morphology and mechanical strength. Response surface methodology (RSM) based on historical data design (HDD) was used to further verify experimental and predicted values for mechanical strength in terms of the three operating parameters mentioned above. The highest mechanical strength of 225.8 MPa was obtained with 37.5 wt% metakaolin content and 3 mL/min of BF flowrate at a sintering temperature of 1500 °C. The desirability of this work is 0.985, indicating that RSM is a suitable approach to validate the effects of fabrication parameters on the mechanical strength of metakaolin-based CHFM. [ABSTRACT FROM AUTHOR]

Asymmetric alumina hollow fiber membranes were prepared using the phase inversion technique followed by the sintering process at high temperatures. The ceramic suspensions were formulated by mixing alumina powder with polyethersulfone (PESf), polyethylene glycol-30-dipolyhydroxystearate and N-methyl-2-pyrrolidone (NMP) as the polymer binder, dispersant and solvent, respectively. The objectives of this study were (i) to investigate the effects of spinning parameters, namely, ceramic loading, ceramic to polymer binder ratio, different internal coagulant temperatures and air gap variation on asymmetric structure formation and (ii) to study the self-cleaning properties of alumina hollow fiber membranes. The ceramic hollow fiber membrane was characterized in terms of its viscosity, structural morphology and mechanical strength using a scanning electron microscope (SEM). The results showed that the finger-like structures in alumina hollow fiber membranes could be formed but their patterns were influenced by the ceramic suspension and spinning parameters. Variations in their morphology resulted in significant effects on the mechanical properties and permeability of ceramic hollow fiber membranes. A CuO/CeO 2 catalyst was deposited onto the alumina membrane support with the catalyst distribution determined by SEM/EDX. Self-cleaning properties were examined by comparing normal cleaning and self-cleaning properties with irradiation of UV for protein rejection. The result of self-cleaning by UV showed higher bovine serum albumin (BSA) permeation due to super-hydrophilicity of the CuO/CeO 2 catalyst. [ABSTRACT FROM AUTHOR]

This work describes the preparation of yttria-stabilized zirconia (YSZ) hollow fibre membranes using the phase inversion and sintering process. The study aims to provide generic information on the effects of membrane preparation on the morphology and mechanical properties of YSZ hollow fibre membranes. In this work, ceramic suspensions were prepared by mixing YSZ particles, dispersant, polymer binder and organic solvent using a planetary ball milling machine. This process was followed by extrusion into a coagulation bath via an air gap, drying and sintering process at temperatures ranging from 1250 °C to 1400 °C. The results show that by varying the YSZ loading and YSZ/PESf ratio, different morphologies of ceramic hollow fiber membranes can be obtained due to variations in the viscosities of ceramic suspensions. Similarly, air-gap length between the spinneret and coagulant surface was found to affect the growth of the finger-like structures and sponge-like regions. Varying these parameters also gave significant effects on the mechanical strength of the ceramic membrane due to the change in membrane thickness and compactness. The sintering process had insignificant effects on the membrane morphology but the process can be used to enhance the mechanical strength of ceramic hollow fiber membranes. The optimum temperature of the sintering process was identified. It was found that increasing the sintering temperature further caused a reduction in the mechanical strength due to crack formation in the ceramic hollow fiber membrane. The preliminary performance tests showed that the ceramic hollow fiber membrane sintered at 1300 °C has a pure water flux of 118.4 L/m 2 h. It also has a high PEG rejection with molecular weight cut off (MWCO) of 60 kDa. [ABSTRACT FROM AUTHOR]