Enhancement of antifouling properties using rice husk silica particles in polysulfone membrane and optimization of its operating condition

This study investigates the effects of rice husk silica (RHS) as additive in the polysulfone membrane to enhance antifouling properties in membrane separation process. The flat sheet PSf/RHS membrane was prepared via phase inversion technique. The characterization and performance test were conducted on PSf ultrafiltration membrane prepared from a different additive concentration. The thermal stability of prepared 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. Meanwhile, the performance was evaluated in term of pure water flux (PWF), rejection and antifouling properties. The optimized of normalized flux (Jf /Jo) at different parameter filtration condition (pH, ionic strength and tranmembranepressure) was carried out by using the response surface methodology (RSM). From the analysis of SEM, FESEM and AFM, results showed that the microstructure of the membrane especially at top layer and sub layer obviously changed with the incorporation of RHS. The results also demonstrated that the mean pore size was decreased and hyrophilicity was increased as increased RHS particles in PSf membrane. The performance of the membrane was analyzed by using distilled water for permeation test and humic acid for the rejection test. The results also showed that the hydrophilic PSf/RHS membrane has significantly improved the permeation and rejection performance after the addition of RHS. The results showed that the addition of 4 wt. % RHS give the highest flux at 300.50 L/m².hour (LMH). The highest rejection was found at 3 wt. % of RHS membrane with value 98% for UV254 and 96% for TOC. The optimal value of Jf/Jo was found at 0.62 with the parameter condition pH: 6.10, ionic strength: 0.05 mol/L and transmembrane-pressure: 2.67 bars. Optimize of RSM analysis also proved that the error of model is less than 0.05% which indicates that the model is significant

Sugarcane green ceramic hollow fibre membrane for oily wastewater separation

Oily wastewater is one of the greatest problems in the world and needs an urgent solution. Therefore, this work describes the preparation of green ceramic hollow fiber membranes derived from waste sugarcane bagasse ash (WSBA) using phase inversion and sintering techniques. The first step in the production of WSBA was the calcination process of sugarcane bagasse at 800 °C followed by characterization 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 WSBA 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 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/m2h at the beginning of the filtration process. The investigation was further towards development of superhydrophobic and superoleophilic green ceramic hollow fibre membrane (ss-CHFM/WSBA) grafted with TEOS and MTES through sol-gel method for separation oily wastewater. Various grafting parameters such effect of grafting time, grafting cycle and calcination temperature were conducted towards membrane performance and morphology. The newly-developed ss-CHFM/WSBA induced excellent wettability properties with contact angle value of 161.1° at 60 min of grafting time, 3 cycle of grafting cycle and calcination temperature at 400 °C. In addition, it was also found that these parameters gave evenly nano-silica particle distribution on the surface. As a result, excellent oil flux (134.2 L/m2h ) and oil separation efficiency (99.9%). Therefore, the optimization of oil condition in term of pH, oil concentration and oil temperature on the ss-CHFM/WSBA performance (oil flux and oil separation efficiency) was evaluated by using response surface methodology (RSM). The optimum ss-CHFM/WSBA performance was predicted at pH 10, 10.01 ppm for oil concentration and 69.04 °C for oil temperature. The verification result was found in acceptable average error at 4.71% for oil flux and 0.746% for oil separation efficiency

Novel superhydrophobic and superoleophilic sugarcane green ceramic hollow fibre membrane as hybrid oil sorbent-separator of real oil and water mixture

The frequent oil spill accidents in nowadays has aroused great attention all over the world. Superhydrophobic and superoleophilic grafted on various substrates have attracted much attention to treat oil and water mixture because of their unique performance that can effectively separate oil and water mixture. At the same time, ceramic membrane also shows potential substrates to be used in treating oil and water mixture. However, conventional ceramic membrane that made from alumina show drawbacks in term of its high cost production. Herein, we report a new ceramic membrane that derived from agricultural-sugarcane bagasse waste and modified into superhydrophobic and superoleophilic to act as hybrid oil sorbent and separator. In this study, we successfully treat three types of real oil and water mixture from palm oil mill effluent (POME), restaurant and car wash with oil rejection and flux up to 99% and 134 L/m2h, respectively. In summary, this work demonstrates a facile, economic and effective method to fabricate superhydrophobic and superoleophilic substrates for oil and water separation

Novel superhydrophobic and superoleophilic sugarcane green ceramic hollow fibre membrane as hybrid oil sorbent-separator of real oil and water mixture

The frequent oil spill accidents in nowadays has aroused great attention all over the world. Superhydrophobic and superoleophilic grafted on various substrates have attracted much attention to treat oil and water mixture because of their unique performance that can effectively separate oil and water mixture. At the same time, ceramic membrane also shows potential substrates to be used in treating oil and water mixture. However, conventional ceramic membrane that made from alumina show drawbacks in term of its high cost production. Herein, we report a new ceramic membrane that derived from agriculturalsugarcane bagasse waste and modified into superhydrophobic and superoleophilic to act as hybrid oil sorbent and separator. In this study, we successfully treat three types of real oil and water mixture from palm oil mill effluent (POME), restaurant and car wash with oil rejection and flux up to 99% and 134 L/m2 h, respectively. In summary, this work demonstrates a facile, economic and effective method to fabricate superhydrophobic and superoleophilic substartes for oil and water separation

Hydrophobic ceramic membrane for membrane distillation: A mini review on preparation, characterization, and applications

Membrane distillation (MD) is one of the emerging separation technologies with extremely high separation factor, especially in desalination application. MD utilizes the hydrophobic membrane which only allows the passage of vapor through the membrane pores. Recent years have witnessed great progress in the development of hydrophobic ceramic membranes for MD applications due to their superior properties over the polymeric counterparts. However, ceramic membranes are hydrophilic in nature; hence, membrane surface modification process is required to acquire hydrophobic properties for MD applications. Direct grafting using silane agents is the most widely used ceramic membrane hydrophobization method. Hence, this mini review provides a complete summary of the research progress on the preparation and characterization of the hydrophobic ceramic membranes through silane agent grafting, as well as their applications in MD. Finally, future research directions have also been addressed

Effect of Kaolin Particle Size Towards Preparation of Kaolin Ceramic Membrane

The purpose of this work is to study the effect of kaolin particle size for the preparation of low cost ceramic membrane suspension and ceramic membrane structure. Kaolin particle size is categorized into two categories; i) ≤ 1µm and ii) ≥ 1 µm. The suspension is prepared via stirring technique under 1000 rpm at 60°C. The particle size of kaolin is characterized using field emission scanning electron microscope (FESEM) and the prepared suspension is characterized in term of its viscosity. Results indicate that the particle size gave significant effect to the viscosity of ceramic membrane suspension. Preliminary data showed that kaolin with particle size ≤ 1µm resulted ceramic membrane with dense structure

High strength and antifouling metakaolin-based ceramic membrane for juice clarification

Key lime, watermelon, and kiwifruit juices were successfully clarified by using a novel high strength and antifouling metakaolinbased ceramic membranes prepared via combination of phase inversion and sintering technique. The fabricated membrane was characterized by utilizing scanning electron microscopy (SEM) analysis, three-point bending strength, juice permeation, and fouling behavior analysis. In this work, the fouling behavior of the membrane was studied using Darcy’s law for cross-flow filtration system. Analysis of the fouling mechanism revealed that the membranes’ fouling was most influenced by the cake filtration mechanism and can be solved easily by applying high operating pressure. Membranes prepared at a sintering temperature of 1300 °C were found to be optimum membranes for juice clarification as it possessed excellent mechanical strength (176.8 MPa) and pure water flux of 273 L/m2 h at 500 kPa. Interestingly, it was also found that the membrane could endure high operating pressure up to 700 kPa, which consequently solved the fouling issue. Thereby, the precious juice properties, such as total suspended solid (TSS), pH, acidity, and density for all juices, were found to be almost unaffected

Removal of As(III) and As(V) from water using green, silica-based ceramic hollow fibre membranes via direct contact membrane distillation

Arsenite [As(III)] and arsenate [As(V)] removal by direct contact membrane distillation (DCMD) using novel hydrophobic green, silica-based ceramic hollow fibre membranes derived from agricultural rice husk was investigated in this work. The green ceramic hollow fibre membranes were prepared from amorphous (ASHFM) and crystalline (CSHFM) silica-based rice husk ash and modified to be hydrophobic via immersion fluoroalkylsilane (FAS) grafting of 1H,1H,2H,2H-perfluorodecyltriethoxysilane. Superhydrophobic contact angle values up to 157° and 161° were obtained for ASHFM and CSHFM, respectively. Remarkably, the membrane surface morphology mimicked a look-alike lotus-leaf structure with decrement in pore size after grafting via the silane agent for both membranes. The effect of arsenic pH (3–11), arsenic concentration (1–1000 ppm) and feed temperature (50–80 °C) were studied and it was found that feed temperature had a significant effect on the permeate flux. The hydrophobic CSHFM, with a flux of 50.4 kg m−2 h−1 for As(III) and 51.3 kg m−2 h−1 for As(V), was found to be the best of the tested membranes. In fact, this membrane can reject arsenic to the maximum contaminant level (MCL) limit of 10 ppb under any conditions, and no swelling mechanism of the membranes was observed after testing for 4 hours

Facile fabrication of superhydrophobic and superoleophilic green ceramic hollow fiber membrane derived from waste sugarcane bagasse ash for oil/water separation

Green ceramic hollow fiber membranes with superhydrophobic and superoleophilic surfaces (ss-CHFM/WSBA) were successfully fabricated via facile sol–gel process using tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES) as precursors. In this work, silica solution was prepared using the modified Sto¨ber method. This process was followed by dipping the pristine membranes into the sol–gel solution at various grafting times (0–90 min), grafting cycles (0–4 cycles), and calcination temperatures (400–600⁰ͦC). The wettability, surface morphology, and chemical composition of the pristine and ss-CHFM/WSBA membranes were investigated. The results showed that increasing the grafting time has increased the wettability of ss-CHFM/WSBA with high contact angle of up to 163.9⁰. Similarly, increasing grafting cycle has enhanced the hydrophobicity of ss-CHFM/WSBA due to the formation of hierarchical structure of grafting cycle which were more than one. The optimum calcination temperature for ss-CHFM/WSBA was identified. It was found that increasing the calcination temperature has degraded the sol template on the surface of ss-CHFM/WSBA, hence decreasing the wettability. The preliminary performance tests showed that ss-CHFM/WSBA grafted at 60 min, 3 cycles, and calcined at 400 ⁰C showed excellent oil/water separation efficiency of 99.9% and oil flux of 137.2 L/m2 h

Toughening of ceramic shell mould with rice husk fiber (CSm-RH) to improve strength property and mould performance

For ages, ceramic shell mould (CSm) have been extensively applied in investment casting industry. The formation of CSm requires multiple steps of dipping, layering drying and firing stages. The later steps are very crucial as the solidification thin layer CSm that consist of loose ceramic particles easily cracks when exposed to the higher thermal effect. The inclusion of fiber or any reinforces phases is able to enhance fired ceramic body and also strengthen the green ceramic structure. Thus, the feasibility of rougher NaOH treated rice husk fiber (RHT) prior embedded into composited structure has shown a significant CSm improvement by induced a better adhesion properties and larger bonding area with brittle ceramic matrix, resulted in increased green strength (1.34 MPa) and fired body strength (4.32 MPa). Owing to the decomposed of lignin layer in CSm with untreated rice husk fiber (CSm-RHU) exhibited a higher porosity that provide a better permeation paths of air flow during molten metal pouring as increased 30 % from the standard CSm permeability, giving an enormous benefit for investment casting cooling process. Overall, the incorporation of RHT fiber in a CSm matrix of both green and fired body governed in toughening of brittle ceramic body, hence avoid failure to the casting mould