Development and characterization of sulfonated polysulfone membrane for proton exchange membrane fuel cell (PEMFC)

Sulfonated polysulfone membranes with varying degree of sulfonation have been successfully synthesized by electrophilic substitution via sulfonation process in this study. Sulfonated dense membranes were fabricated using locally available pneumatically controlled casting machine. Characterizations of different degree of sulfonated polysulfone membranes were conducted through swelling effects, ion exchange capacity (IEC), Thermal Gravimetric Analysis (TGA), Differential Scanning Calorimeter (DSC), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and proton conductivity measurement. It was observed that an increase in the degree of sulfonation increases the water uptake of the membranes and sulfonic acid group in the polymer membrane. From FTIR, it was clearly confirmed the occurrence of sulfonation in the polymer structure as the evidence of the SO3 stretching band was noticed at frequency of 1027 cm-1. It was found from TGA that the sulfonic acid group started to decompose at 250ºC and decomposition of the polymer main chain decreases by increasing the degree of sulfonation. The Tg value detected in this study was increased accordingly with the degree of sulfonation though some hindrance was found to decrease the Tg value during the experiments. Proton conductivity measurement of sulfonated polysulfone membrane was found to increase with operating temperature and degree of sulfonation. It was found that at higher temperature (80ºC), SPSU10 membrane exhibits proton conductivity value at par with that of Nafion 117 membrane. It was also observed from XRD analysis that dimethylformamide solvent was prone to form hydrogen bonding with sulfonic groups hence allows formation of a more regular structure which leads to an incipient crystalline character of the material structure. SEM micrographs showed clearly the altered microstructure of polysulfone polymer before and after the sulfonation process

Smart photocat reactor for remote CECs removal

The product powered by photovoltaic solar panel is an efficient system which can be remotely installed in any onsite location for CECs removal. Photocatalyts combined with superior adsorptive nanocomposite to degrade the contaminant from any source of wastewater at faster rate

Nanocomposite ultrafiltration membranes incorporated with zeolite and carbon nanotubes for enhanced water separation

The objective of this work is to develop a new class of nanocomposite ultrafiltration (UF) membranes with excellent solute rejection rate and superior water flux using zeolitic imidazolate framework-8 (ZIF-8) and multi-walled carbon nanotubes (MWCNTs). The effect of ZIF-8 and MWCNTs loadings on the properties of polyvinyldifluoride (PVDF)-based membrane were investigated by introducing respective nanomaterial into the polymer dope solution. Prior to filtration tests, all the membranes were characterized using several important analytical instruments, i.e., SEM-EDX and contact angle analyzer. The addition of the nanoparticles into the membrane matrix has found to increase the membrane pore size and improve its hydrophilicity compared to the pristine membrane. The separation performance of membranes was determined with respect to pure water flux and rejections against bovine serum albumin (BSA) and humic acid (HA).The experimental findings indicated that the nanocomposite membranes in general demonstrated higher permeation flux and solute rejection compared to the pristine membrane and the use of ZIF-8 was reported to be better than that of MWCNTs in preparing nanocomposite UF membranes owing to its better flux and high percentage of solute rejection

Comprehensive evaluation of the integrated membrane contactor-microalgae photobioreactor system for simultaneous H2 purification and CO2 treatment from biomass fermented gases

Biohydrogen (H2) has been identified as a potential renewable energy source to substitute energy-based fossil fuel that can be produced from biomass fermentation. However, carbon dioxide (CO2) is also commonly present in the biogas mixture and must be properly treated as it could contribute to the climate change phenomenon. In this study, an integrated membrane contactor-microalgae photobioreactor system is applied to allow simultaneous H2/CO2 treatment from biomass fermented biogases. A comprehensive evaluation of the effectiveness of the integrated system was investigated by screening the essential operating parameters of the system using One Factor at a Time (OFAT) technique followed by optimization Response Surface Methodology (RSM). Serial investigations of the process parameters, the optimum condition was at a pH of 10 with gas and liquid flow rates at the respective levels of 0.1 L/min and 0.5 L/min, while the microalgae concentration was 0.6 g/L. At these optimum conditions, the H2 purity was found to have increased remarkably, from 69.4% to 83.2%. In a long-term separation performance using the optimized conditions, microalgae solution was found to be capable of sustaining its performance at a longer time with only 2% performance dropped observed within 540 min of the operational time. In conclusion, the use of microalgae in a membrane contactor system could be a promising technique for treating these fermented gases, in a move towards carbon neutrality

Recent progress and challenges in hollow fiber membranes for wastewater treatment and resource recovery

Membrane processes have been extensively employed in diverse applications, specifically in industrial wastewater treatment. The technological development in membrane processes has rapidly advanced and accelerated beyond its common principle and operation. Tremendous efforts have been made in the advancement of membrane materials, fabrication method, membrane modification and integration with other technologies that can augment the existing membrane processes to another level. This review presents the recent development of hollow fiber membranes applied in wastewater treatment and resource recovery. The membrane working principles and treatment mechanism were discussed thoroughly, with the recent development of these hollow fiber membranes highlighted based on several types of membrane application. The current challenges and limitations which may hinder this technology from expanding were critically described to offer a better perspective for this technology to be adopted in various potential applications

Insights into membrane distillation application for textile wastewater treatment – A review

Textile wastewater must be effectively treated with the best available technology prior to release to receiving water bodies to prevent its impact on the environment. Apparently, membrane distillation shows great potential in treating textile wastewater a part of the complexity of the textile wastewater composition. This membrane process enables the water vapour to pass through its porous hydrophobic membrane and retains the concentrated pollutants to be transported. This paper provides data and information from previous studies using membrane distillation to treat textile wastewater. An overview of the development of membrane distillation as well as the fundamental theory is presented. Recent progress in the application of membrane distillation in textile wastewater is then discussed. The final part of the paper looked at the future orientation of this technology to be acceptable in the industrial sector, especially for the textile industry

Recent progress and challenges in hollow fiber membranes for wastewater treatment and resource recovery

Membrane processes have been extensively employed in diverse applications, specifically in industrial wastewater treatment. The technological development in membrane processes has rapidly advanced and accelerated beyond its common principle and operation. Tremendous efforts have been made in the advancement of membrane materials, fabrication method, membrane modification and integration with other technologies that can augment the existing membrane processes to another level. This review presents the recent development of hollow fiber membranes applied in wastewater treatment and resource recovery. The membrane working principles and treatment mechanism were discussed thoroughly, with the recent development of these hollow fiber membranes highlighted based on several types of membrane application. The current challenges and limitations which may hinder this technology from expanding were critically described to offer a better perspective for this technology to be adopted in various potential applications

Comparison of separation performance of absorption column and membrane contactor system for biohydrogen upgraded from palm oil mill effluent fermentation

The adverse effects of ammonia found in wastewater streams lead to the development of advanced water treatment technology, i.e. membrane contactor (MC). In this study, single layer hollow fibre membrane (SLZK) and dual layer hollow fibre membrane (DLZK) were prepared from zirconia and kaolin and modified into hydrophobic membrane through simple grafting process via fluoroalkylsilane (FAS) agent. The properties of membranes such as morphology, surface roughness, mechanical strength, wettability and liquid entry pressure were analysed through scanning electron microscopy (SEM), atomic force microscopy (AFM), 3-point bending strength, contact angle and LEPw setup. Finally, the performance of the membranes was also investigated towards ammonia removal via membrane contactor system. Our findings showed that hydrophobicity properties significantly improved for both SLZK and DLZK membranes after grafting modification process as indicated by the increase of contact angle value from 5° and 1° to 132.7° and ~180.0° respectively. Based on the morphological analysis, the surface of DLZK showed more porous structure as compared to the SLZK. In addition, DLZK also displayed the highest mechanical strength and contact angle reading of 125 MPa and ~180° respectively. This suggests that the DLZK showed an excellent membrane contactor performance with highest value of mass transfer coefficient (3.77 x 10-5 ms-1) and almost complete removal of ammonia removal (91%). Overall, these results implied that dual layer ceramic membrane developed from kaolin and zirconia could provide the basis for the development of alternative ceramic membrane with excellent properties for membrane contactor system

Fabrication of nanocomposite membrane via combined electrospinning and casting technique for direct methanol fuel cell

Emergence of nanotechnology has resulted in the introduction of the electrospinning process in fabricating and characterising the polymer electrolyte membrane from the sulfonated poly (ether ether ketone) (SPEEK) nanocomposite membrane comprised of electrospun Cloisite15A® (e-spun CL) for direct methanol fuel cell (DMFC). Poly (ether ether ketone) polymer is sulfonated up to 63% by sulfuric acid. SPEEK63/e-spun CL nanofibers were fabricated via electrospinning in which SPEEK63 was used as carrier polymer while the SPEEK63/e-spun CL nanocomposite membrane was obtained by the casting method. Characterizations on physical, morphological and thermal properties of SPEEK63/e-spun CL were conducted and compared to the SPEEK membrane fabricated by casting simple mixing 2.5wt.% Cloisite15A® and 5.0wt.% triaminopyrimidine solution (SPEEK63/2.5CL/5.0TAP). Scanning electron microscopy (SEM) showed well electrospun Cloisite15A® with an average diameter nanofiber around 187.4 nm. Moreover, field emission scanning electron microscopy (FESEM) revealed that Cloisite15A® particles at a nanometer range were uniformly distributed and 66% smaller than those in SPEEK63/2.5CL/5.0TAP. Furthermore, x-ray diffraction proved that the dispersion state of Cloisite15A® fell into an intercalated phase. A very small amount of Cloisite15A® (0.05wt.%) in SPEEK63/e-spun CL successfully enhanced the proton conductivity up to 50%, whereas, unfortunately the methanol permeability value was 27 times higher than SPEEK63/2.5CL/5.0TAP. Proton conductivity and methanol permeability of SPEEK63/e-spun CL were 24.49 x 10-3 Scm-1 and 3.74 x 10-7 cms-1, respectively. Even though this study contributed to 95% selectivity lower than SPEEK63/2.5CL/5.0TAP, electrospinning showed a promising technique to further reduce original sized Cloisite15A® particles from mixed size (μm and nm) to nanometer sized. In addition, by fine tuning, the dispersion of Cloisite15A® enhances the SPEEK63/e-spun CL performance in DMFC

Fabrication and characterisation of superhydrophobic bio-ceramic hollow fibre membranes prepared from cow bone waste

Superhydrophobic membranes have great potential towards various application, especially for thermal-based membrane system such as membrane distillation. In this study, bioceramic hollow fibre membranes derived from cow bone waste were prepared by phase inversion/sintering method, followed by surface modification via immersion grafting with fluoroalkylsilane (FAS) agent. Interestingly, the grafting process led to the formation of hydroxyapatite nanorods, mimicking the unique structure of electrospun nanofiber membranes. The hydrophobicity of the modified membranes was assessed by measuring the water contact angle and showed excellent improvement from hydrophilic property to superhydrophobic with the highest value of 174° After the modification, the water entry pressure also improved from 0 to 1 bar. In addition, the presence of FAS agent on the membrane surface was observed using X-ray photoelectron spectroscopy (XPS). A correlation between pore size, porosity, and mechanical strength of the modified membrane was discussed; the increment of membrane pore size after grafting process is synonym to the dental erosion mechanism. The result indicates that the superhydrophobic bioceramic hollow fibre membranes derived from cow bone waste have significant potential to be developed for membrane distillation application in treating water and wastewater