Novel hydroxyapatite-based bio-ceramic hollow fiber membrane derived from waste cow bone for textile wastewater treatment

Industrial textile wastewater is toxic due to the presence of recalcitrant color pigments and poisonous heavy metals. In this study, the hydroxyapatite (HAp)-based bio-ceramic hollow fiber membranes (h-bio-CHFM) were developed via the combined phase inversion and sintering technique. It was found that the properties of the developed h-bio-CHFMs were greatly affected by the HAp content of the ceramic suspension, and sintering temperature. The h-bio-CHFM with the sintering temperature of 1200 degrees C exhibited the long rod-shaped HAp particles and the smallest pore size (0.013 mu m). High removals of color (99.9%), COD (80.1%), turbidity (99.4%) and conductivity (30.1%) were achieved using the h-bio-CHFM sintered at 1200 degrees C with stable high flux of 88.3 L/m(2)h. Remarkably, the h-bio-CHFM sintered in the temperature range of 1000-1200 degrees C also demonstrated excellent adsorption ability towards heavy metals with 100% removals. The results of this study show the potential of the h-bio-CHFM for the efficient industrial textile wastewater treatment applications

A low cost, superhydrophobic and superoleophilic hybrid kaolin-based hollow fibre membrane (KHFM) for efficient adsorption-separation of oil removal from water

Inspired by the lotus leaf surface structure, which possesses a hydrophobicity behaviour, a low cost, high performance superhydrophobic and superoleophilic kaolin hollow fibre membrane (KHFM) was obtained by a simple sol-gel grafted method using tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES) for oil removal from water. The KHFM was grafted at various grafting times ranging from 1 to 5 coating cycles. Prior to the calcination process at 400 °C, the grafted KHFM was dried in an oven at 100 °C for 1 hour for each grafting coating cycle. The grafting process efficiency was measured by the contact angle of water and hexane. Scanning electron microscopy (SEM) and Atomic Force Microscopy (AFM) were used to study the morphology and surface roughness, respectively, of the grafted KHFM. The oil removal was conducted by using the homogeneous mixture of hexane and water. The highest hydrophobicity and oleophilicity was obtained for the KHFM grafted at 2 coating cycles with a contact angle value equal to 157° and 0°, respectively. In fact, the mechanical strength of KHFM was also improved from 16.21 MPa to 72.33 MPa after grafting. In terms of performance, KHFM grafted for 2 coating cycles obtained an almost 99.9% absorption of oil. Thereby, KHFMs were assembled into a module for a filtration study. A high oil flux of 102 L m-2 h-1 was obtained for superhydrophobic and superoleophilic KHFM with 2 grafting coating cycles of 2, and this result is in agreement with the trend of the adsorption result

Preparation and characterization of inexpensive kaolin hollow fibre membrane (khfm) prepared using phase inversion/sintering technique for the efficient separation of real oily wastewater

A low-cost kaolin hollow fiber membrane (KHFM) with unique finger-like and spongelike structures was successfully fabricated by utilizing cheap and abundantly available kaolin clay as the starting material via phase inversion/sintering technique. In this study, mixing kaolin particles prepare the ceramic suspension, dispersant, polymer binder, and solvent using a planetary ball mill. This process is then followed by extrusion at various kaolin contents, bore fluid flow rates, and sintering temperatures ranging from 1200 to 1500 degrees C. The effect of calcium carbonate (CaCO3) content and polyethylene glycol (PEG) molecular weight as a function of pore agents are also discussed. Membrane characterizations were performed in terms of morphology, pore size distribution, porosity, mechanical strength, contact angle value, and pure water flux. The performance of membranes towards oil-in-water separation was conducted using oily wastewater samples taken from three points in Johor, Malaysia which were Kluang Oil Palm Mill Sdn. Bhd. in Kluang district, a car wash in Taman Skudai Baru in Johor Bahru district, and Meranti cafe, Universiti Teknologi Malaysia (UTM). The optimum parameters in fabricating the inexpensive KHFM were identified. It was found that the increase of kaolin content, bore fluid flow rate, and sintering temperature gave insignificant effect in the formation of finger-like structure but the process can be used to find a defect-free (i.e., rounded lumen and sufficient thickness) hollow fiber membrane shape. Interestingly, the finger-like structure can be controlled by the addition of PEG as a pore agent at different molecular weights. KHFM prepared with PEG 30,000 as a pore agent offered the highest oil rejection of 99.99% of turbidity and total organic carbon (TOC), and 91.8% of chemical oxygen demand (COD) with stable high flux of 320 L/m(2)h for all oily wastewater samples

Stability study of triple layer hollow fiber in solid oxide fuel cell with methane as fuel

Solid oxide fuel cell (SOFC) is an attractive device that can convert chemical into energy. Recently, the triple layer hollow fiber (TLHF) opens up a new discovery of higher power output. This study investigates the fabrication of TLHF in solid oxide fuel cell consisting anode/anode functional layer (AFL)/electrolyte (NiO-YSZ/NiO-YSZ/YSZ) via single-step phase inversion-based co-extrusion combined with co-sintering technique using methane as fuel. TLHF formed sandwich-like structure that corresponds to the anode and AFL with dense electrolyte. Initially, the open circuit voltage (OCV) was 1.1 V, after 90 min, the OCV dropped to 0.2 V due to the carbon deposits that caused poisoning. Meanwhile, the power density also reduces from 0.8 to 0.33 Wcm−2. SEM image carbon shows the carbon deposited causing crack and reached electrolyte layer. TEM of the Ni catalyst indicates there are multilayer of graphite exhibit at the Ni particle courtesy of the carbon deposits. The results showed the graphite causing the performance to decrease which is corresponding to the usage of methane as fuel

Antifouling polysulfone membranes blended with green SiO2 from rice husk ash (RHA) for humic acid separation

This study investigated the effects of silica prepared from rice husk (RHA) as an antifouling additive in the polysulfone (PSf) membrane. The ultrafiltration mixed matrix PSf/rice husk silica (RHS) flat-sheet membrane was prepared via phase inversion technique at different percentages of silica concentration. The characterization and performance test were conducted on the prepared membrane. The thermal stability of the membrane was observed by using thermogravimetric analysis (TGA). The cross section area and particles distribution of additive were carried out by using the scanning electron microscope (SEM) while the surface morphology was investigated via field emission scanning electron microscope (FESEM). The surface roughness and hydrophilicity were also determined by using atomic force microscopy (AFM) and contact angle measurement respectively. The performance of the membrane was evaluated in terms of pure water flux (PWF), humic acid rejection and antifouling properties. The results of SEM, FESEM and AFM revealed that the incorporating of RHS improved the microstructure of the membrane especially at top layer and sub layer. The results also demonstrated that the mean pore size decreased and the hyrophilicity increased with an increase of RHS particles in PSf membrane. The performance result was found that the addition of RHS in the PSf membrane significantly improved the PWF, rejection and antifouling properties. The results indicated that the addition of 4 g RHS give the highest flux at 300.50 L/m2 h (LMH) and excellent mitigating fouling. The highest rejection was found at 3 g of RHS with a value of 98% for ultraviolet light (UV254) and 96% for Dissolved Organic Carbon (DOC)

Preparation and characterization of low cost porous ceramic membrane support from kaolin using phase inversion/sintering technique for gas separation: effect of kaolin content and non-solvent coagulant bath

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

Ceramic membrane distillation for desalination

Membrane distillation (MD) is a thermally driven membranous process and in the recent years, it has received increasing attention in desalination. Generally, polymeric membranes have dominated the MD studies due to their intrinsic hydrophobic properties and high availability. On the other hand, the development of ceramic membranes for MD desalination is developing, gradually replacing their polymeric counterparts due to superior properties in terms of thermal, chemical and mechanical stabilities, as well as potentially longer service terms. This review describes and evaluates the fabrication methods of ceramic membranes as well as discusses the latest discoveries of ceramic membranes for MD desalination. Despite outstanding properties, the efforts in developing ceramic membranes as a replacement for polymeric membranes in MD desalination are meeting challenges and obstacles; hence, in the last part of this article, the current challenges and future research opportunities of ceramic membrane development will also be addressed

Superhydrophobic ceramic hollow fibre membranes for trapping carbon dioxide from natural gas via the membrane contactor system

The membrane contactor system is one of the most important technologies to trap CO2 from natural gas. To apply this technology, hollow fibre membranes with a superhydrophobic surface must be used, where membranes were prepared from kaolin clay through the phase inversion/sintering technique and modified by three types of fluoroalkylsilane (FAS) molecules (C6, C8, C10) at different immersion times (6, 24, 48,72 h) to capture CO2 from natural gas via contacting the gas-liquid system. The kaolin was chosen due to its abundant availability at an affordable price as well as the high amount of the hydroxyl (OH) group in the surface which easily reacts with FAS during the grafting process. Superhydrophobicity was distinguished by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), liquid entry pressure of water (LEPw) measurement, and contact angle (CA). The lowest pore size of the grafted membrane obtained for C8 was about 1.32 μm; it was considered the perfect target for high membrane resistance. The chosen superhydrophobic kaolin membrane was tested for carbon dioxide (CO2) capture via the membrane contactor system. With increasing time of immersion, the hydrophobicity phenomena rose gradually until superhydrophobicity property was obtained. Forty-eight hours was proven as sufficient time to obtain the desired superhydrophobicity property to avoid wetting pores of the membranes. Besides, the perfect type of FAS for separating CO2 was C8 based on the sufficient LEPw and contact angle. The reduction of pH was observed after testing the performance of using a membrane contactor to separate CO2 by using water as absorbent where pH value decreased from 6.6 to 4.3 within 1 h, which concludes the success of the gas-liquid system into removing CO2 from natural gas

Carbon dioxide capture using a superhydrophobic ceramic hollow fibre membrane for gas-liquid contacting process

This work initiates the development of clean technology in carbon dioxide (CO2) capture using ceramic membrane inspired by gas–liquid contacting system. A low cost, high performance superhydrophobic kaolin-alumina hollow fibre membrane was prepared via phase inversion-based extrusion and sintering techniques, followed by a grafting with fluoroalkylsilane (FAS). The membrane was characterized by scanning electron microscopy (SEM), gas permeation test, contact angle, wetting resistance, X-ray photoemission spectroscopy (XPS), X-ray diffraction (XRD) and thermal gravimetric analysis (TGA). The fabricated membrane was highly porous, thus increasing the gas permeation rate. By surface modification, the membrane contact angle was increased from 0° to 142°. In fact, wettability resistance of the membrane was also improved. The membrane was subsequently applied in membrane contactor for carbon dioxide (CO2) absorption. The CO2 absorption flux as high as 0.18 mol m−2 s−1 was achieved at the liquid flow rate of 100 mL min−1 which was far above the fluxes of some commercial and in-house made polymeric and ceramic membranes. In conclusion, the modified kaolin-alumina hollow fibre membrane with the superhydrophobic surface, high permeance, and absorption flux is suitable for CO2 post-combustion capture, due to its outstanding chemical and thermal stabilities