Publications

Omniphobic PTFE based Hollow Fiber Membrane with ZnO Nanoparticles Deposition via Universal Spray Technique

This investigation aimed to enhance the hydrophobicity of a polytetrafluoroethylene (PTFE) hollow fiber membrane, transforming it into an omniphobic surface. This was achieved by coating the membrane with a mixture of zinc oxide nanoparticles (ZnO-NPs) and polyvinylidene fluoride-cohexafluoropropylene (PVDF-HFP) using the universal spray technique. The membrane's morphology and performance were evaluated based on the number of spray cycles, which influenced the coating thickness on the membrane surface. The spraying process was varied up to 4 cycles to determine the membrane with the most effective deposition of ZnO NPs in terms of water contact angle and liquid entry pressure (LEPw). Results indicated that the membrane spray-coated up to 4 cycles, denoted as PTFE-4, exhibited a rough hierarchical re-entrant morphology, imparting omniphobic characteristics. The optimized membrane demonstrated a high water contact angle of 170° and a liquid entry pressure of 2.6 bar. Fourier-transform infrared (FTIR) and energy dispersive analysis of X-rays (EDX) confirmed the successful chemical integration of ZnO NPs onto the commercial membrane. This research holds significance for the future of membrane distillation in treating wastewater containing low surface tension pollutants.

Structure formation in anode and its effect on the performance of micro-tubular SOFC: a brief review

Anode-supported micro-tubular solid oxide fuel cell (SOFC) offers many advantages over the electrolyte and cathode-supported configurations in terms of simplicity, reliability, and efficiency. In such design, the anode substrates should possess a highly porous structure, provide active sites reaction as well as serving good mechanical strength. This structure is desired to provide enough fuel, which in turn increases the reaction rate and reduces the concentration polarisation. Hence, pore formation in anode become a key parameter in producing high performance micro-tubular SOFC. This review is mainly focusing on the fabrication of anode substrate for micro-tubular SOFC, the types of pores in anode structure and its effect to the cell performance.

Electrospun membranes for UF/NF/RO/FO/PRO membranes and processes

Membrane technology has been deployed in wastewater treatment and downstream processes in various industrial applications. Recently, electrospun nanofibrous membranes (ENMs) have gained interest due to their broad range of filtration applications owing to interconnected pore structure, high surface area as well as porosity, and ease of functionalization. This chapter provides a comprehensive review of ENMs on the novel applications for both pressure-driven and osmotically driven membrane separation processes. The study primarily outlines the principles of membrane separation processes. The significance of functionalized ENMs is discussed by their application for desalination, wastewater treatment, and bioseparation via ultrafiltration (UF), nanofiltration (NF), forward osmosis (FO), and reverse osmosis (RO). ENMs fouling is also discussed in the individual membrane separation process. The challenges of ENMs for industrial-scale applications are also addressed. Overall, this study would provide a hint on the recent development of ENMs in water treatment and bioseparation applications.

Fixed-Bed Studies of Landfill Leachate Treatment Using Chitosan-Coated Carbon Composite

The feasibility of a chitosan-coated coconut-shell (CS) carbon composite for landfill leachate treatment in a fixed-bed study was investigated in terms of COD and NH3-N removal. The surface of the composite was characterized using SEM, FT-IR, and XRD to assess any changes before and after column operations. To enhance its cost-effectiveness, the saturated composite was regenerated using NaOH. The results showed that the composite had significantly better removal of both COD and NH3-N, as compared to CS and/or chitosan (p ≤ 0.05; ANOVA test), respectively. The breakthrough curve obtained from the fixed-bed studies exhibited an ideal “S” shape. The breakthrough points for the adsorbents followed the order of CS at BV 76 < chitosan at 200 BV < composite at BV 305. It was also found that a low flow rate and deeper bed depth of the packed adsorbent were necessary for achieving optimal column operations. The composite achieved 96% regeneration in the first cycle. However, even with the enhanced adsorption of target pollutants by the composite through chitosan coating, the treated effluents still could not meet the required COD and NH3-N effluent limits of less than 200 and 5 mg/L, respectively, as mandated by legislation. Nonetheless, the findings suggest that low-cost composites derived from unused resources can be employed as effective adsorbents for wastewater treatment.

A novel imogolite-reinforced sulfonated polyphenylsulfone as proton exchange membrane in fuel cell applications

The high ion exchange capacity of sulfonated polyphenylsulfone (SPPSU) consists of nanotubular inorganic clay that was developed as a proton exchange membrane for fuel cell application. The nanotubular imogolite (Im) was incorporated into SPPSU polymer matrix under various loading (0.5 wt%, 1 wt%, and 2 wt%) and subjected to thermal annealing up to 180 ºC. Upon heat treating at 180 ºC, SPPSU-Im nanocomposite membranes showing homogenous membrane structure and improved water uptake at higher water temperature compare to pristine SPPSU membrane. The strength of the nanocomposite membrane is decreasing upon the incorporation of the imogolite fillers. Hence, at lower relative humidity conditions, the SPPSU-Im nanocomposite membrane resulting in six times higher proton conductivity than the SPPSU membrane. Furthermore, at 80 °C under fully hydrated conditions, 1 wt% of Im incorporate into the SPPSU matrix can achieve the maximum power density up to 89.8 mW/cm2, which is about 16% higher than the maximum power density produce by SPPSU membrane in single-cell proton exchange membrane fuel cell (PEMFC) system. The results indicating that the imogolite reinforced SPPSU polymer matrix shows significant improvements on the SPPSU polymer matrix as PEM in fuel cell applications.

Continuous monitoring of crude oil movement in an electromagnetic-assisted enhanced oil recovery process using a modified fiber Bragg grating sensor

The Fiber Bragg grating (FBG) sensor used for distinguishing the oil movement offers detailed insights about the reservoir oil and is the key to quantifying the impact on improvement and the integrity and efficiency of the wells. The modified FBG sensors proposed in this paper through a partially un-cladding process and magnetostrictive nanolayer coating could advantageously monitor the crude oil mobility in electromagnetic-assisted enhanced oil recovery operations. The remaining ∼400 nm thickness of cladding after partial removal was coated with ∼100 nm magnetostrictive Ni-Fe nanolayer. The structures of Ga-doped magnetite and Ga-doped hematite were found orthorhombic with Pnma space group and rhombohedral with R3C space group, with the corresponding remnant magnetization (retentivity) value of 94 Oe and 150 Oe, respectively. The magnetization values at 1.5 T were 30 for Ga-doped magnetite and 21 emu/g for Ga-doped hematite nanoparticles. The interfacial tension of crude oil and brine dropped for 16.9 % and 4.1 % when the Ga-doped magnetite and the Ga-doped hematite nanofluid were injected, respectively. The correlated contact angle for the Ga-doped magnetite was 65.2˚, while for the Ga-doped hematite, it was 57.4˚. The FBG’s responses to different nanofluids and surfactant injection at the presence of electromagnetic field indicated the high sensitivity of the probe against the induced magnetic field, which was varied as a function of distance, nanofluids type, and nanoparticles accumulation near the FBG sensing point. The increase in the wavelength shift of FBG by flowing the nanofluids through the sandstone and opposite behavior was recorded by surfactant flowing. The maximum wavelength shift was 0.21 nm when Ga-doped magnetite nanofluid was injected, whereas it was 0.14 when Ga-doped hematite was injected.

Treatment of As(III)-Laden Contaminated Water Using Iron-Coated Carbon Fiber

This work presents the fabrication, characterization, and application of iron-coated carbon fiber (Fe@CF), synthesized in a facile in situ iron reduction, for As(III) removal from an aqueous solution. The physico-chemical properties of the composite were characterized using Brunauer-Emmett-Teller (BET) surface area, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) spectroscopy. Adsorption studies were evaluated in batch experiments with respect to reaction time, the dose of adsorbent, As(III) initial concentration, pH, and co-existing ions. The results showed that the BET surface area and pore volume of Fe@CF slightly decreased after Fe coating, while its pore size remained, while the SEM and XRD analyses demonstrated that the Fe was successfully anchored on the CF. A maximum As(III) adsorption of 95% was achieved with an initial As concentration of 1.5 mg/L at optimum conditions (30 min of reaction time, 1 g/L of dose, 1 mg/L of As(III) concentration, and pH 3.5). Since the treated effluents could not meet the strict discharge standard of ≤10 μg/L set by the World Health Organization (WHO), a longer reaction time is required to complete the removal of remaining As(III) in the wastewater effluents. As compared to the other adsorbents reported previously, the Fe@CF composite has the highest As(III) removal. Overall, the findings suggested that the use of Fe@CF as an adsorbent is promising for effective remediation in the aquatic environment.

Enhanced hydrophilic polysulfone hollow fiber membranes with addition of iron oxide nanoparticles

Membranes are at the heart of hemodialysis treatment functions to remove excess metabolic waste such as urea. However, membranes made up of pure polymers and hydrophilic polymers such as polyvinylpyrrolidone suffer problems of low flux and bio-incompatibility. Hence, this study aimed to improve polysulfone (PSf) membrane surface properties by the addition of iron oxide nanoparticles (IONPs). The membrane surface properties and separation performance of neat PSf membrane and membrane filled with IONPs at a loading of 0.2 wt% were investigated and compared. The membranes were characterized in terms of morphology, pure water permeability (PWP) and protein rejection using bovine serum albumin (BSA). A decrease in contact angle value from 66.62° to 46.23° for the PSf/IONPs membrane indicated an increase in surface hydrophilicity that caused positive effects on the PWP and BSA rejection of the membrane. The PWP increased by 40.74% to 57.04 L m−2 h−1 bar−1 when IONPs were incorporated due to the improved interaction with water molecules. Furthermore, the PSf/IONPs membrane rejected 96.43% of BSA as compared to only 91.14% by the neat PSf membrane. Hence, the incorporation of IONPs enhanced the PSf hollow fiber membrane hydrophilicity and consequently improved the separation performance of the membrane for hemodialysis application. © 2017 Society of Chemical Industry

Microbial Fuel Cells (MFC): A Potential Game-Changer in Renewable Energy Development

Currently, access to electricity in the cities of the Global South is so limited that electrification remains low in rural areas. Unless properly tackled, one-third of the world’s cities will suffer from energy scarcity. The emergence of microbial fuel cell (MFC) technology accelerates the deployment of decentralized and sustainable energy solutions that can address the looming energy shortage. This review consolidates scattered knowledge into one article about the performance of MFC in optimizing electricity generation from phosphorus (P)-laden wastewater, while removing the target nutrient from wastewater simultaneously. It is obvious from a literature survey of 108 published articles (1999–2022) that the applications of MFC for building a self-powered municipal water treatment system represents an important breakthrough, as this enables water treatment operators to generate electricity without affecting the atmospheric balance of CO2. Using a pyrite-based wetland MFC, about 91% of P was removed after operating 180 days, while generating power output of 48 A/m2. Unlike other techniques, MFCs utilize bacteria that act as micro-reactors and allow substrates to be oxidized completely. The Earth’s tiniest inhabitants can efficiently transform the chemical energy of organic matter in unused wastewater either into hydrogen gas or electricity. This facilitates wastewater treatment plants powering themselves in daily operation or selling electricity on the market. This MFC technology radically changes how to treat wastewater universally. By exploring this direction along the water–energy–food nexus, MFC technology could transform wastewater treatment plants into a key sustainability tool in the energy sector. This suggests that MFCs provide a practical solution that addresses the need of global society for clean water and electricity simultaneously.

A review study of nanofibers in photocatalytic process

Clean water resources are dwindling due to the rapid development of industrialization, population growth and long-term drought has become an issue worldwide. With this growing demand, various practical strategies and solutions have been adopted to yield more viable water resources. Over the last decades, a great deal of interest has been focused on the membrane and photocatalytic process of organic compounds present in water and wastewaters by using a catalyst in the form of nanoparticles or nanofibers. The paper presents an overview of the photocatalytic process and the application of using nanofibers in the process. Different modifications of photocatalyst are described. Advantages of the nanofiber application for photocatalytic process are discussed. Moreover a short introduction of producing the nanofibers using an electrospinning process is given.

A Brief Review on Utilization of Hybrid Nanofluid in Heat Exchangers: Theoretical and Experimental

No abstract is provided for this article.

Tailoring the oxidative stability of magnetically oriented polybenzimidazole-based membrane and proton conductivity performances for fuel cell applications

Recent development of mixed matrix membrane as a membrane bioreactor for wastewater treatment: A review

Wastewater treatment has emerged as the most effective method for addressing the scarcity of clean water, which is expected to cause a worldwide crisis in the near future. The membrane bioreactor (MBR) is a cutting-edge technology that combines membrane filtration with biological activity in the form of microorganisms. MBR has been considered the most efficient approach so far owing to its high effluent and relatively small space requirements. The membrane constituent material is an important aspect of producing MBR with maximum process performance. This study extensively evaluated the application of polymers, ceramics, and mixed matrix membranes (MMM) in wastewater treatment performance. MMM has better performance due to its hydrophilic nature, good chemical, mechanical, and thermal stability, and ease of synthesis. Various types of filler in MMM for MBR applications are also discussed, including metals, metal oxides, carbon, MOF, silica, and zeolite. The addition of fillers in the polymer matrix has been able to improve the characteristics of the membrane, including water flux, rejection of pollutants, and resistance to fouling. Subsequently, several important parameters of MMM that affect the performance of MBR, including hydrophilicity, surface charge, surface roughness, module, pore characteristics, and filler charge, have been reviewed. An investigation of the performance of the MBR, such as activated sludge characteristics, operating conditions, and fouling phenomena, is presented. Lastly, this review describes the challenges and perspectives of developing MMM-based MBR in the future.

Effects of hydrophilic surface macromolecule modifier loading on PES/O-g-C3N4 hybrid photocatalytic membrane for phenol removal

HydrophiLic surface modifying macromolecules (LSMM) modified polyethersulfone (PES) based photocatalytic membranes have been successfully prepared. This hybrid photocatalytic membrane applying oxygen-doped graphitic carbon nitride (g-C3N4) as a photocatalyst was successfully fabricated via phase inversion technique in flat sheet form at ambient temperature. The potential of LSMM as membrane modifier was explored in detail under various loadings (1–5 wt%). The results show that the LSMM addition successfully increased the membrane hydrophilicity which may consequently prevent the membrane from comprehensive fouling. More appearance of g-C3N4 on the membrane surface was observed by Scanning Electron Microscopy (SEM) and Atomic Force Microscope (AFM) analyses upon the LSMM addition. However, the trend tended to decline at the loading beyond 4 wt% of LSMM. At 4 wt% of LSMM, the PES/g-C3N4 membrane successfully decreased phenol concentration up to 35.78% and rejected 14.73% of phenol. From the water flux result, the application of LSMM in water treatment application was hindered by the flux deterioration but a considerably high flux for an ultrafiltration membrane. The results indicate that the introduction of LSMM in the PES/g-C3N4 hybrid photocatalytic membrane showed the great potential of LSMM as a membrane surface modifier for photocatalytic activities and membrane separation performance.

Photoreactor-ultrafiltration hybrid system for oily bilge water photooxidation and separation from oil tanker

A novel design of hybrid system consisting of photoreactor (PR) combined with ultrafiltration (UF) membrane was investigated for oily bilge water degradation and separation from oil tanker. Initially, the bilge organic compounds were photooxidized using ultraviolet type A (UVA) light irradiation on 100, 200 and 300ppm of TiO2. Further TiO2 and oxidized oily bilge water was filtered using hollow fiber membrane separator, which was prepared by polyvinylidene fluoride (PVDF) and halloysite nanotubes. The hollow fiber membranes were characterized by ATR-IR spectrum, thermal gravimetric analysis (TGA), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and X-ray photoelectron spectroscope (XPS). Individual hydrocarbon of oily bilge water was identified by using gas chromatography–mass spectrometry (GC–MS) analysis. According to the GC–MS analysis, over 90% decomposition of oil in bilge water has occurred by 200 and 300ppm of TiO2 suspension. On the other hand, pH meter showed that, decomposed oily bilge water was more acidic, which increased to pH7 after UF system process. Moreover, over 99% of degraded oil in bilge water was filtered by this promising hybrid system.

Magnetite thin films grown on different flexible polymer substrates at room temperature: Role of antiphase boundaries in electrical and magnetic properties

Currently, there is an enormous need for flexible electronic devices given their astonishing competencies. In this view, we investigated the structural, electrical, and magnetic characterstics of magnetite (Fe3O4) thin films with a thickness of 100 nm prepared using a reactive RF sputtering technique at 300 K on polycarbonate (PC), polymethyl methacrylate (PMMA), and polythene terephthalate (PET) flexible substrates. The structural properties showed that the films grown on PC, PMMA, and PET substrates exhibited the pure form of Fe3O4 nanostructures by flowing oxygen with a flow rate of 3.5 sccm. The Verwey transition temperatures (T v ) of ∼123 K, ∼124 K, and ∼126 K; saturation magnetization (Ms) values of ∼220 emu/cm3, ∼235 emu/cm3, and ∼261 emu/cm3; and magnetoresistance (MR) values of −7.1%, −7.3%, and −7.8% under the H ∥ Film plane below 60 kOe at 300 K for 100-nm-thick Fe3O4 film on PC, PMMA, and PET substrates respectively were observed. These remarkable results were interpreted and the effect of antiferromagnetically (AFM) coupled antiphase boundaries (APBs) was explained, which suggested that Fe3O4/PET heterostructure can be a most promising component for flexible spintronics.

Influence of mesoporous phosphotungstic acid on the physicochemical properties and performance of sulfonated poly ether ether ketone in proton exchange membrane fuel cell

This study demonstrates the successful development of hybrid mesoporous siliceous phosphotungstic acid (mPTA-Si) and sulfonated poly ether ether ketone (SPEEK) as a proton exchange membrane with a high performance in hydrogen proton exchange membrane fuel cells (PEMFC). SPEEK acts as a polymeric membrane matrix and mPTA-Si acts as the mechanical reinforcer and proton conducting enhancer. Interestingly, incorporating mPTA-Si did not affect the morphological aspect of SPEEK as dense membrane upon loading the amount of mPTA-Si up to 2.5 wt%. The water uptake reduced to 14% from 21.5% when mPTA-Si content increases from 0.5 to 2.5 wt% respectively. Meanwhile, the proton conductivity increased to 0.01 Scm−1 with 1.0 wt% mPTA-Si and maximum power density of 180.87 mWcm−2 which is 200% improvement as compared to pristine SPEEK membrane. The systematic study of hybrid SP-mPTA-Si membrane proved a substantial enhancement in the performance together with further improvement on physicochemical properties of parent SPEEK membrane desirable for the PEMFC application.

The Effect of Temperature, Sulfonation, and PEG Addition on Physicochemical Characteristics of PVDF Membranes and Its Application on Hemodialysis Membrane

Polyvinylidene fluoride (PVDF) membrane and its derivative have been investigated the permeation ability for creatinine and urea. The membrane was made by an inversion precipitation system in N,N-dimethyl acetamide (DMAc) and water as non-solvents. In this study, the modification of PVDF membrane permeability with PEG additives, CBT variations, and sulfonation was successfully carried out. The membrane solidification process was carried out on three variations of the coagulation bath temperature (CBT): 30, 45, and 60 °C. Eight types of membranes were characterized by using FT-IR and TGA/DSC, followed by the analysis of their porosity, hydrophilicity, water uptake, swelling degree, tensile strength, and permeability of creatinine and urea. The FT-IR spectra indicate that PVDF modification has been successfully carried out. The porosity, hydrophilicity, water uptake, and swelling degree values increase with the modification of functional groups. Furthermore, improvements in creatinine and urea permeability and clearances are achieved by increasing CBT and sulfonation in the PVDF/PEG membrane. The presence of sulfonate groups improves the membrane permeability through the interaction of intermolecular hydrogen with water and dialysate compounds. The existence of PEG as a porogen enhanced membrane porosity. Creatinine and urea clearance values increase from 0.29–0.58 and 6.38–20.63 mg/dL, respectively.