Publications

Membranes and Membrane Processes

This chapter presents the development of membranes and membrane processes. The first part of this chapter addresses the fundamental principle of the membrane, including the definition of a membrane and its performance parameters, i.e., flux and selectivity. The membrane processes are influenced by their classifications, i.e., membrane's material type, separation regime, and membrane geometry. The examples of membrane processes according to a driving force such as transmembrane pressure (microfiltration, ultrafiltration, nanofiltration, reverse osmosis), concentration gradient (forward osmosis), and vapor partial pressure gradient (gas separation, membrane distillation) are included. The chapter ends with a discussion on the fouling issues in membrane applications.

Overcoming challenges in water purification by nanocomposite ceramic membranes: A review of limitations and technical solutions

Water purification from various sources is crucial in mitigating global water shortage and ensuring universal access to clean and safe drinking water. Incorporation of nanoparticles, such as titania (TiO2) or zirconia (ZrO2) into/onto ceramic membranes (nanocomposite ceramic membranes) is a promising modified version of conventional ceramic membranes and has emerged as a highly viable solution for enhancing water purification processes due to their outstanding properties in improving membrane properties compared to conventional ceramic membranes. However, nanocomposite ceramic membranes encounter significant obstacles, including poor dispersion of nanoparticles within the membrane matrix, the potential for nanoparticle leaching during the purification process, and the accumulation of fouling agents. Despite the limited number of reviews on nanocomposite ceramic membranes in water purification applications, the uniqueness of this review is addressing these limitations and examines recent technical solutions, developments, and strategies to overcome these challenges and enhance their performance. By effectively addressing these limitations through improved nanoparticle dispersion and attachment in the membrane matrix and enhanced fouling resistance properties, cutting-edge strategies can be developed to optimize nanocomposite ceramic membranes and significantly improve their performance across various water purification applications. This review also discusses the research outlook of incorporating nanomaterials with ceramic membranes, modification techniques and the effect of nanomaterials on ceramic membrane properties. Although recent advancements in nanocomposite ceramic membranes for water purification, significant limitations persist. Therefore, this review also highlights the future research direction to enhance the properties and performance of nanocomposite ceramic membranes in water purification applications.

Effects of lanthanum strontium cobalt ferrite (LSCF) cathode properties on hollow fibre micro-tubular SOFC performances

No abstract is provided for this article.

Novel self-cleaning PVDF/MoO3/ZnO/GO dual layer hollow fiber photocatalytic membrane with excellent photocatalytic performance of EDCs removal and energy storage capability

Endocrine-disrupting chemicals (EDCs) have a wide range of detrimental effects on health, particularly on the human endocrine system. Efflux This research study involves the application of - molybdenum trioxide, zinc oxide and graphene oxide (MoO3/ZnO/GO) with polyvinylidene fluoride (PVDF) membrane as photocatalytic dual layer hollow fiber (DLHF) membrane as novel energy storage photocatalytic membrane towards efficient degradation of EDCs under visible light illumination. Ternary MoO3/ZnO/GO was synthesized using hydrothermal method and was embedded on the surface of dual layer hollow fiber membrane by dry-wet spinning method by varying the GO loading at 0.1, 0.25 and 0.5 wt%. The results indicated that the 0.5 PVDF/MoO3/ZnO/GO DLHF photocatalytic membrane exhibited improved wettability, high porosity, good water flux, and exceptional EDCs removal, achieving removal rates of 73.08%, 75.80%, 73.65%, 100%, 95.57%, and 53.50% for 1 mg/L BPA, 1 μg/L BPA, 2 μg/L gabapentin, 1 μg/L diclofenac, 10 μg/L caffeine, and 6 μg/L nonylphenol, respectively after 240 min of light exposure. Besides, energy storage capability achieved 96.07% rejection of 1 mg/L BPA in dark condition while stability and reusability test showed 0.5 PVDF/MoO3/ZnO/GO DLHF achieve 74.02% regeneration efficiency after 3 consecutive cycles. Furthermore, the photocatalytic properties of 0.5 PVDF/MoO3/ZnO/GO DLHF could assure a self-cleaning property and increase its lifetime. The PVDF/MoO3/ZnO/GO DLHF photocatalytic membrane served as a versatile 3-in-1 solution, enhancing photocatalytic degradation and rejection capabilities while also serving as a promising energy storage material with self-cleaning properties for removing EDCs from aquatic environments, regardless with or without the presence of light.

Fabrication, characterization, and application of ternary magnetic recyclable Bi2WO6/BiOI@Fe3O4 composite for photodegradation of tetracycline in aqueous solutions

We aim at fabricating a ternary magnetic recyclable Bi2WO6/BiOI@Fe3O4 composite that could be applied for photodegradation of tetracycline (TC) from synthetic wastewater. To identify any changes with respect to the composite's morphology and crystal structure properties, ΧRD, FTIR, FESEM-EDS, PL and VSM analyses are carried out. The effects of Fe3O4 loading ratio on the Bi2WO6/BiOI for TC photodegradation are evaluated, while operational parameters such as pH, reaction time, TC concentration, and photocatalyst's dose are optimized. Removal mechanisms of the TC by the composite and its photodegradation pathways are elaborated. With respect to its performance, under the same optimized conditions (1 g/L of dose; 5 mg/L of TC; pH 7; 3 h of reaction time), the Bi2WO6/BiOI@5%Fe3O4 composite has the highest TC removal (97%), as compared to the Bi2WO6 (63%). After being saturated, the spent photocatalyst could be magnetically separated from solution for subsequent use. In spite of three consecutive cycles with 71% of efficiency, the spent composite still has reasonable photocatalytic activities for reuse. Overall, this suggests that the composite is a promising photocatalyst for TC removal from aqueous solutions.

Improving Water Flux of Uio-66 Immobilized on Ceramic Hollow Fiber

The study focused on the development of a modified membrane using a zirconium-based metal–organic framework (UiO-66) to enhance the desalination process in the membrane distillation system. UiO-66 was successfully synthesised on an alumina hollow fiber before fluoroalkylsilane grafting. The effect of UiO-66 concentration loading during membrane fabrication was examined concerning membrane porosity, performance, wettability and surface roughness. Hydrophobic UiO-66 membranes with a contact angle ranging from 130.9° to 139.1° were obtained. The modified membranes were tested in direct contact membrane distillation. With increasing UiO-66 concentration, water fluxes increased from 1.30 to 12.01 kg/m2∙h, and the membrane with 0.4 M of UiO-66 achieved the highest water flux. The optimum membrane was further evaluated under direct contact membrane distillation for seawater desalination to investigate performance stability. The membrane demonstrated a water flux of 9.26 kg/m2∙h with 100% salt rejection. Moreover, the membrane powder maintained its crystallinity in seawater, demonstrating its long-term stability and substantial capabilities in terms of desalination.

Effect of triple-tail surfactant on the morphological properties of polyethersulfone-based membrane and its antifouling ability

No abstract is provided for this article.

The feasibility study of CAU-1 as an adsorbent for Cu, Zn, Pb, As, Fe and endocrine disrupting chemical bisphenol-A (BPA)

This work discusses the feasibility of CAU-1 as an adsorbent for both heavy metals and bisphenol A (BPA). CAU-1 was synthesised solvothermally at 120 °C for 8 h. Batch adsorption study was done to investigate the feasibility of CAU-1 as the adsorbent. The CAU-1 weight was constant throughout the study, 0.01 g. CAU-1 was characterised using zeta potential analysis, SEM, FTIR, TGA, and XRD. CAU-1 was only able to remove BPA and not able to adsorb heavy metals due to the repulsion forces between CAU-1 and the heavy metals. Thus, BPA was used as adsorbate for CAU-1 adsorption study. The optimum conditions for BPA adsorption on CAU-1 were at pH 7 and 3 h contact time. The adsorption capacity increased infinitely with increasing concentration of the BPA. The maximum equilibrium adsorption capacity (qe) of CAU-1 for BPA was 310.1 mg/g at 25 °C, and the adsorption followed the pseudo-second-order kinetic model. The thermodynamic studies indicate that the adsorption reaction is a spontaneous and endothermic process, a favourable reaction.

Photocatalytic degradation of nonylphenol using co-extruded dual-layer hollow fibre membranes incorporated with a different ratio of TiO2/PVDF

A photocatalytic reactor based on novel dual-layer hollow fibre membranes with immobilized titanium dioxide (TiO2) nanoparticles was proposed in this study and tested for the degradation of highly recalcitrant endocrine disrupting compound of nonylphenol (NP). The presence of TiO2 on the outer surface of dual-layer hollow fibres was confirmed by scanning electron microscopy (SEM), energy dispersion of X-ray (EDAX), and atomic force microscopy (AFM). The effect of TiO2 loading, where the mass fraction TiO2/PVDF was varied from 0 to 1, on the degradation of toxic NP was evaluated by high-performance liquid chromatography (HPLC). The addition of TiO2 nanoparticles showed a significant effect on the membrane pore size and NP degradation rate. The presence of TiO2 on the outer layer of dual-layer hollow fibre membranes actively functioned as a photocatalyst, with the hollow fibre of TiO2/PVDF ratio of 1 possessed the highest NP degradation rate.

Effect of operating temperature on the behavior of promising SPEEK/cSMM electrolyte membrane for DMFCs

The behavior of sulfonated poly (ether ether ketone) (SPEEK) with different degrees of sulfonation (DS) (60–76%) blended with charged surface modifying macromolecule (cSMM) at different operating temperatures as an electrolyte membrane for direct methanol fuel cell (DMFC) application has been studied. A good DMFC electrolyte membrane should possess high proton conductivity and low methanol permeability. In this work, the fabricated SPEEK/cSMM membranes were compared with pure SPEEK and commercial Nafion 112 membranes in terms of water uptake, proton conductivity, and methanol permeability at temperature range of room to 80°C. The water uptake of SPEEK/cSMM membranes increased with the temperature and it was higher than that of SPEEK and Nafion 112 membranes; however newly fabricated membranes with 68% and 76% DS were dissolved at high temperatures although showed the same trend at lower temperatures. In agreement with the result of water uptake, proton conductivity of SPEEK/cSMM membranes also increased with temperature and was higher as compared to the corresponding SPEEK membranes; however it was still lower than that of Nafion 112. The methanol permeability values of the SPEEK/cSMM membranes were lower at different temperatures as compared to corresponding SPEEK and Nafion 112 at the same condition. Owing to considerable proton conductivity and lower methanol permeability values, SPEEK60/cSMM exhibited the highest overall performance than other tested membranes at 60°C. These results indicated that SPEEK60/cSMM membrane is promising to be used as a polymer electrolyte membrane in direct methanol fuel cell.

Selective ultrasensitive FBG-SBL chemosensor for detection of copper ions in water resources based on plasmon resonance energy transfer

In this study, the gold (Au) coated fiber Bragg grating (FBG) probe decorated with Schiff base ligands (SBL) with variable denticity is proposed as a susceptible sensor for monitoring the copper ions (Cu2+) concentration in an aqueous solution. The sensing principle can be attributed to the interaction of the SBL coated on Au/FBG, which serves as anionic chelates with Cu2+, altering the environment refractive index and changing the surface plasmon resonance (SPR) condition. The sensitivity and limit of detection (LOD) through a Bragg wavelength shift are measured to be 23.1 pm/µM and 0.07 µM respectively, with a dynamic range of up to 4  µM (µM, 2.5 ppm), which is within the acceptable limit specified by the World Health Organization (WHO) for safe drinking water (1.3 ppm). The probe shows an assertive coordination behaviour towards Cu2+ for selective detection compared to other heavy metals. Excellent reusability (6 trial times) and specificity and portability make FBG-SBL chemosensor suitable for online monitoring of water resources.

The effect of deposition time on the morphology of CuS electrodes fabricated by chemical bath deposition for supercapacitor applications

This paper presents the synthesis of copper sulfide (CuS) electrode utilizing chemical bath deposition (CBD) and the study of the effect of complexing agent on the morphology of CuS electrode. The aim of this study is to find the ideal time for the synthesis of CuS and to find the capacitance and highest potential of the CuS electrode synthesized at the ideal time. In this project, CuS solution is formed using copper (II) sulphate (CuSO4) solution, thioacetamide solution, and a complexing agent which is citric acid. Homogeneous ultrathin nanospheres of CuS thin films have been successfully developed on nickel foam (NF) by simple and low-cost CBD method which is a promising electrode material for high-performance supercapacitors. The CBD process was carried out at different time intervals which are 30, 60, 90 and 120 min to find the ideal deposition time for CuS/NF electrode fabrication. The surface morphological analysis showed uniform growth of CuS nanospheres on NF surface. Structural analysis confirms the formation of hexagonal crystal structure of CuS. The electrochemical performances were tested by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance techniques. The best capacitance that was recorded by CuS fabricated at 60 min with a specific capacitance of 615 F/g at 1 A/g current density. Hence, the ideal deposition time of CuS/NF electrode fabrication for high supercapacitor performance is 60 min. The encouraging results suggest that CuS nanoflakes prepared by chemical bath deposition can serve as promising electrode materials for high performance supercapacitors in the future.

First demonstration of room temperature synthesized NH2-MIL-101(Fe) as a photo fenton catalyst: Comprehensive stability assessment via advanced characterisations

Porous polyether sulfone for direct methanol fuel cell applications: Structural analysis

Porous poly ether sulfone (PES) membranes were prepared using two different solvents which were N-methyl-2-pyrrolidone and dimethylacetamide (DMAc) via dry/wet non-solvent phase inversion (NIPS) techniques. PES with the compositions of 18 wt% is prepared for each dope solution. During the membrane casting process, 0 to 5 minutes delay prior to immersion in coagulant bath is set in order to allow solvent evaporation to take place. Water is used as the non-solvent for solvent exchange process. The prepared membranes are characterised based on their morphological aspect using scanning electron microscopy towards the effect of solvent evaporation time and solution viscosity. The changes in proton conductivity, methanol permeability, water uptake and hydrophilicity/hydrophobicity behaviours are also studied. Conclusively, the 18 wt% PES membranes prepared with DMAc as solvent at 3 minutes solvent evaporation time exhibited desirable pore size for proton conduction (0.04 × 10−3 Scm−1) and methanol resistant effect that consequently contribute to considerably low methanol permeability rate at 0.06 × 10−7 cm2 s−1 which could elevate the direct methanol fuel cell performance.

Membrane fouling in desalination and its mitigation strategies

Water scarcity at global level has called for attentions to establish new and innovative technologies that can be tapped to provide sustainable solutions to water crisis. Membrane-based desalination has been acknowledged as one of the promising approaches to resolve the global challenges. Currently, different membrane-based technologies have been deployed worldwide for clean water production. However, despite the great advances made in terms of the permeate flux and rejection, the practical application of membrane for desalination is still limited by the inevitable membrane fouling issue. Membrane fouling is known to be the major culprit to the elevated operating costs due to the deterioration of permeate flux, increasing transmembrane pressure, and frequent chemical cleaning which shorten the membrane's lifespan. This review provides insights into the recent advancement in mitigating membrane desalination fouling. The fouling control strategies which encompass the efforts made in the novel membrane development, feed water pretreatment, and membrane cleaning are highlighted. The advantages and limitations of these techniques are discussed and reviewed based on a substantial number of up-to-date literatures.

Future research perspectives in hemodialysis membrane technology

Hemodialysis is the prevailing approach in renal replacement therapy, critically required for eliminating uremic toxins from the blood of individuals suffering from end-stage renal disease (ESRD), but its efficacy is hindered by membrane biocompatibility and inadequate removal of uremic toxins. Blood-membrane interactions during HD trigger immune responses, impacting thrombogenesis, complement activation, leukocyte activation, coagulation, cytokine production, and oxygen radical generation. Despite research progress, membrane biocompatibility remains a global concern due to potential harm, morbidity, and mortality. This article reviews dialysis fundamentals, encompassing historical context, the evolution of configurations and materials, commercially available membranes, challenges, and recent advancements in HD membranes furthermore this review highlights the impacting clinical studies conducted for hemodailysis advancement. It emphasizes the critical need for improved hemocompatibility, discussing recent research and techniques like surface modifications and coating. These approaches aim to minimize platelet activation, coagulation, and enhance membrane performance, showcasing promising potential for future improvements in dialysis outcomes and patient comfort.

Round-the-Clock Pvdf/Cuo-Vs4 Dual Layer Hollow Fibre Photocatalytic Membrane for Bisphenol a Degradation

Endocrine disrupting compound (EDC) namely bisphenol A (BPA) is toxic and has capability to give adverse effect towards health. The outflow of BPA into water bodies raised concern and suitable water treatment is needed. Photocatalysis is promising method nowadays to move towards green technology. The combination of copper (II) oxide-vanadium tetrasulfide (CuO-VS4) incorporated with polyvinylidene fluoride (PVDF) membrane as photocatalytic dual layer hollow fibre membrane (DLHF) was chosen in this study as novel energy storage photocatalytic membrane towards efficient degradation of BPA under visible light illumination. CuO and CuO-VS4 was synthesized via sol-gel and hydrothermal method respectively at different drying temperature and hydrothermal time. PVDF/CuO-VS4 DLHF photocatalytic membrane was fabricated using co-extrusion method by varying the ratio of CuO-VS4 and characterized for the morphology and properties as well photocatalytic test by collecting the sample from photoreactor. CuO synthesized at room temperature while CuO-VS4 synthesized at 12 hours hydrothermal time was chosen to be depositing into PVDF membrane matrix. The 0.25 PVDF/CuO-VS4 DLHF exhibit the largest pore size and uniform distribution of CuO-VS4 while photocatalytic activity achieved 70.19% and 73.24% of photodegradation and removal of BPA respectively. Around 53.09% of BPA successfully degraded after 120 min of analysis in dark condition for efficient energy storage capability. A novel PVDF/CuO-VS4 DLHF can act as preferential photocatalytic membrane for BPA removal and as potential energy storage material for wastewater treatment.

Enhancement of organic solar cell efficiency by altering the zinc oxide photoanode nanostructure morphology

No abstract is provided for this article.