Ceramic membranes offer considerable promise for future industrial applications due to their superior chemical, mechanical, and thermal stabilities, resistance to harsh operating conditions, and long‐term operating processes. However, several bottlenecks still limit their commercial scale‐up in filtration and separation applications, including brittleness, the high costs of conventional ceramic materials, and fouling. Despite several articles in the literature on ceramic membranes, this review focuses on recent progress, technical strategies, and methods to mitigate these limitations that significantly impact their separation and filtration performance. The use of alternative naturally occurring ceramic materials to mitigate the high costs of conventional ceramic materials is discussed, as well as strategies to improve the mechanical strength of brittle ceramic membranes by increasing sintering temperatures and using support materials. Additionally, advanced techniques to mitigate fouling accumulation and wetting in the pores and on the ceramic membrane surface, such as increasing membrane hydrophilicity and surface modification, are addressed. Despite progress in technical solutions for mitigating the bottlenecks of ceramic membranes, these limitations persist. Therefore, the present limitations and future research directions are highlighted.
A co‐extrusion technique was employed to fabricate a novel dual layer NiO/NiO‐YSZ hollow fiber (HF) precursor which was then co‐sintered at 1,400 °C and reduced at 700 °C to form, respectively, a meshed porous inner Ni current collector and outer Ni‐YSZ anode layers for SOFC applications. The inner thin and highly porous “mesh‐like” pure Ni layer of approximately 50 μm in thickness functions as a current collector in micro‐tubular solid oxide fuel cell (SOFC), aiming at highly efficient current collection with low fuel diffusion resistance, while the thicker outer Ni‐YSZ layer of 260 μm acts as an anode, providing also major mechanical strength to the dual‐layer HF. Achieved morphology consisted of short finger‐like voids originating from the inner lumen of the HF, and a sponge‐like structure filling most of the Ni‐YSZ anode layer, which is considered to be suitable macrostructure for anode SOFC system. The electrical conductivity of the meshed porous inner Ni layer is measured to be 77.5 × 10 5 S m –1 . This result is significantly higher than previous reported results on single layer Ni‐YSZ HFs, which performs not only as a catalyst for the oxidation reaction, but also as a current collector. These results highlight the advantages of this novel dual‐layer HF design as a new and highly efficient way of collecting current from the lumen of micro‐tubular SOFC.
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In this study, low-cost magnesium bentonite (MB) was used for the fabrication of bentonite hollow fibre (BHF) membrane with high pure water flux. MB powder was initially characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), particle size distribution (PSD) analyser, Brunnauer -Emmett- Teller (BET) method, and field emission scanning electron microscope (FESEM). The BHF membrane obtained was then fabricated through dope suspension mixing, phase inversion and sintering process. The dope suspension was prepared by mixing MB, dispersant, polymer binder, and solvent using a planetary ball mill. While the spinning process was carried out at the extrusion rate of 8 mL/min, a fluid bore rate of 10 mL/min and air gap of 5 cm, and this was followed by sintering operation at 950 °C, 1000 °C, 1050 °C, and 1100 °C. The resulting BHF membrane was characterized by scanning electron microscopy (SEM) and XRD; the porosity test, water flux and oil rejection were also examined. The SEM surface morphology of BHF at sintering temperature of 950 °C showed spongy-like and nested macrovoids structure; the porosity was 49.09% with a mean pore size of 3.9 µm. The performance test on the bentonite-based hollow fibre membrane showed that the membrane prepared at 20 wt% and sintering temperature of 1000 °C, which induced high and stable permeate water flux and oil rejection of BHFC membrane were 544 L/m2 h and 97%, respectively. The results have shown that the presence of magnesium in bentonite can enhance and promote the needed support material for the fabrication of hollow fibre ceramic membrane.
In this study, polyethersulfone (PES) hollow fiber membranes (HFM) were fabricated with different weight percentage (wt. %) of polymer at 16 wt. %, 18 wt. % and 20 wt. %, in order to study the impact of polymer weight percentages on membrane properties and its dye rejection performance. Microfiltration HFM were fabricated by using the laboratory dry-wet spinning method. In order to improve the pore structure of the polymer membrane, 3 wt. % of (PVP) of 8000 M.W. was added in the dope solution. All the fabricated PES hollow fiber membranes were characterized using the Scanning Electron Microscopy (SEM), Atomic Force Microscope (AFM), Fourier Transform Infrared Spectroscopy (FTIR) and the contact angle. The HFM’s performance was evaluated in terms of dye rejection, by using Direct Red 80 dye as substitute of organic dye in wastewater. The results ed that the membrane with higher weight percentage of PES polymer (20 % PES) had thicker separation layer, smoother membrane surface and uniform like pore structures. The membrane with the higher weight percentage of polymer (20% PES) had higher dye rejection percentage (67.33%) and higher permeate flux (10.024 L/m2h) compared to 16 wt. % and 18 wt. %. The results of this study revealed that the weight percentage of polymer in the membrane did affect the membrane properties and its performance.
This paper reports the preparation of the dual layer ceramic hollow fiber membrane that made of alumina and a mixed ion electron conducting (MIEC) material for simultaneous reaction and separation applications. Alumina hollow fiber membrane was prepared using the phase inversion process followed by a sintering technique at elevated temperature. The alumina hollow fiber membrane was used as membrane support onto which a thin and dense layer of lanthanum strontium cobalt ferrite (LSCF) was deposited. The main objective of this study was to investigate the LSCF coating formulations used in the deposition of LSCF layer onto alumina substrate membrane. The sintering temperature of thin LSCF layer was varied to investigate gas-tightness properties of LSCF membrane. A series of characterizations were conducted for both the support and the LSCF membrane. The result showed that the thin layer membranes with thicknesses ranging from 3 to 20 μm were successfully deposited on the surface of alumina hollow fiber support. The sintering process improved the gas-tightness properties but the sintering temperature above 1150°C caused defects on the surface of LSCF membrane.
The paper describes the preparation of lignin filled natural rubber latex composite and its subsequent use to obtain lignin modified rubber. Two types of lignin i.e.: rubber wood and commercial alkali lignin were used as rubber filler. Gum rubber sheets were prepared from the lignin modified rubber and their properties were compared to Standard Malaysian Rubber (SMR 20) and a type of rubber obtained from the coagulation of high ammonia latex. Rubber morphology was investigated using Scanning Electron Microscope on the cross-sectional area of cryo-fractured samples. Oil resistance of the rubber sheets was determined by measuring the mass change before and after ASTM IRM 903 oil immersion, while the tensile strengths were determined according to ASTM D412 standard. Low values of tensile strength obtained for the commercial alkali lignin modified rubber sheet relative to the rest of the rubber samples was attributed to poor lignin dispersion. This occurrence was substantiated by the SEM analysis of cryo-fractured samples where crazes and inhomogeneity was observed. Nonetheless, both lignin modified rubbers exhibited higher level of oil resistance compared to SMR 20. This is due to the nature of lignin as a hydrophilic component and its presence in the rubber matrix complicates the oil diffusion process into rubber.
The Majallah al-Aḥkām al-‘Adliyyah belongs to the Ottoman Empire has been introduced in Johor, Malaysia during the reign of Sultan Abdul Hamid II (1876-1908). The book was brought to the Johor Government in 1893 during the reign of Johor’s Sultan Abu Bakar (1862-1895) in its Arabic language and it was translated later into Malay language and Jawi script during the reign of Sultan Ibrahim (1895-1959) in 1913. The translation was done by the Mufti of Johor and it is known as the Majalah Ahkam Johor. The book is a legal reference comprises the civil matters of muamalat, for example sale and purchase, rent and hibah, besides of containing court proceedings too. There are previous studies which affirmed that the Majalah Ahkam Johor was rarely used as a reference in court due to the expansion of colonial British in Malaya. The objective of this paper is to discuss and analyse the challenges of the use of the book in Johor and the obstacles in it’s implementation. The methodology of this study is based on qualitative design with historical research approach and document analysis from primary and contemporary data. The findings of this study shows that the use of the Majalah Ahkam Johor at the court level faced obstacles due to the British administration policy of interfering with the state legal and judicial system. Furthermore, the introduction of British law led to the abandonment of the use of Majalah Ahkam Johor as a reference on Islamic matters in Johor.
