Norhaniza Yusof

A review on the fabrication of electrospun polymer electrolyte membrane for direct methanol fuel cell

Proton exchange membrane (PEM) is an electrolyte which behaves as important indicator for fuel cells performance. Research and development (R&;D) on fabrication of desirable PEM have burgeoned year by year, especially for direct methanol fuel cell (DMFC). However, most of the R&;Ds only focus on the parent polymer electrolyte rather than polymer inorganic composites. This might be due to the difficulties faced in producing good dispersion of inorganic filler within the polymer matrix, which would consequently reduce the DMFCs performance. Electrospinning is a promising technique to cater for this arising problem owing to its more widespread dispersion of inorganic filler within the polymer matrix, which can reduce the size of the filler up to nanoscale. There has been a huge development on fabricating electrolyte nanocomposite membrane, regardless of the effect of electrospun nanocomposite membrane on the fuel cells performance. In this present paper, issues regarding the R&;D on electrospun sulfonated poly (ether ether ketone) (SPEEK)/inorganic nanocomposite fiber are addressed.

Effect of evaporation time on cellulose acetate membrane for gas separation

Throughout this decades, membrane technology has been the desirable option among the others gas separation technologies. However, few issues have been raised regarding the membrane gas separation application including the trade-off between its permeability and selectivity and also its effects towards environment. Therefore, for this research, a biopolymer membrane for gas separation application will be developed with reasonably high on both permeability and selectivity. The main objective of this research is to study the effect of solvent evaporation time on the flat sheet asymmetric membrane morphology and gas separation performance. The membranes were produced by a simple dry/wet phase inversion technique using a pneumatically controlled casting system. The dope solution for the membrane casting was prepared by dissolving the cellulose acetate (CA) polymer in N-Methyl-2-pyrrolidone (NMP) and the solvent evaporation time was varied. Permeability and selectivity of the membrane was performed by using pure gases of carbon dioxide, CO2 and methane, CH4. The increase in solvent evaporation time had improved the membrane morphologies as the porosity of the membrane surface decrease and formation of a more mature skin layer. The gas permeation tests determined that increasing in solvent evaporation time had increased the selectivity of CO2/CH4 but reduce the permeability of both gases

Efficient reduction of graphene oxide nanosheets using Na2C2O4 as a reducing agent

The efficient synthesis of reduced graphene oxide (RGO) nanosheets via chemical reduction process of exfoliated graphene oxide (GO) nanosheets was performed by introducing sodium oxalate (Na2C2O4) as a reducing agent. To study the effects of the reduction time on the synthesized RGO, the GO was reduced within -1/2, 1 and 2 h for RGO-1, RGO-2 and RGO-3, respectively. The C/O atomic ratio of the synthesized RGO-3 has increased from 2.16 to 6.32 after reduction as determined by X-ray photoelectron spectroscopy (XPS). The morphology analysis of the RGO-3 was determined by high-resolution transmission electron microscopy (HRTEM) almost revealed the formation of single layer. The number of RGO layers decreases as the time of the reduction increases. Based on these analysis results, sodium oxalate plays an important role in the efficient removal of the oxygen containing groups in the GO to produce high quality of RGO.

Enhancement in photocatalytic degradation of methylene blue by LaFeO3-GO integrated photocatalyst-adsorbents under visible light irradiation

Perovskite LaFeO3 photocatalyst prepared by using sol-gel glucose method was assembled on graphene oxide sheets to produce integrated photocatalyst-adsorbents (IPCA) and investigated as photocatalyst for the degradation of methylene blue under visible light irradiation. The prepared photocatalyst was characterized by FTIR, XRD, FESEM, BET specific surface area measurement, TEM/HRTEM and UV-Vis spectroscopy analysis. The FTIR, FESEM and TEM analysis has suggested that the photocatalyst LaFeO3 has been successfully embedded at the surface of the graphene oxide (GO) sheets due to a strong interaction between the photocatalyst and the adsorbents matrix. Methylene blue degradation shows that IPCA possesses higher photodegradation kinetics compared to bare LaFeO3 photocatalyst. The resultant photocatalyst also possesses magnetic properties which can overcome the difficulty in recollecting and removal of photocatalyst suspension in water after photocatalytic treatment.

Penyediaan dan pencirian gentian-nano karbon teraktif pada kepekatan zink oksida yang berbeza

The study deals on the modified PAN-based activated carbon nanofibers (ACNFs) embedded with different amount of zinc oxides (ZnO) (0, 5, 10, and 15% relative to PAN wt.) to be used as adsorbents for natural gas adsorption. The nanofibers (NFs) were successfully fabricated via electrospinning process at optimize parameters. The resultant NFs underwent three steps of pyrolysis process which are stabilization, carbonization and activation at optimum parameters. The morphological structure and diameter of pure and modified ACNFs were characterized using SEM while the existences of chemical bonds were analyzed by FTIR analysis. XRD analysis was done to identify the crystallinity of the ACNFs. BET method was used to identify the specific surface area (SSA) and nitrogen adsorption isotherm of the samples. The results showed that the SSA of ACNF5 (163.04 m2/g) is significantly higher compared to the pristine and other modified ACNFs, nevertheless the obtained results is much lower compared to average theoretical value. SEM micrograph depicted that all ACNF samples possessed average diameter of 300-500 nm with smooth and aligned structure. The presence of white spots as ZnO alongside the NFs has been confirmed with FTIR and XRD analysis. From these findings, it is believed that ACNFs/ZnO will become a new adsorbent with great potential for gas adsorption and storage in the near future applications.

Methane adsorption capacity on graphene derived from glucose and ferric chloride

This study examines the methane adsorption capacity using graphene derived from glucose and ferric chloride (FeCl3). The graphene was prepared via simple method by dissolution of glucose and FeCl3 in water, vaporization of water in oven, and calcination process in quartz furnace. Graphene was successfully produced with impregnation ratio of glucose and FeCl3 at 1:1 and calcination temperature of 650 °C. The prepared graphene subsequently underwent a volumetric adsorption setup, to measure the adsorption capacity of methane (CH4). The highest CH4 adsorption capacity obtained was 6.37 mmol/g at 3.5 bar and 298 K for 40 minutes. These result shows that the prepared graphene displayed good adsorption characteristic for CH4.This study examines the methane adsorption capacity using graphene derived from glucose and ferric chloride (FeCl3). The graphene was prepared via simple method by dissolution of glucose and FeCl3 in water, vaporization of water in oven, and calcination process in quartz furnace. Graphene was successfully produced with impregnation ratio of glucose and FeCl3 at 1:1 and calcination temperature of 650 °C. The prepared graphene subsequently underwent a volumetric adsorption setup, to measure the adsorption capacity of methane (CH4). The highest CH4 adsorption capacity obtained was 6.37 mmol/g at 3.5 bar and 298 K for 40 minutes. These result shows that the prepared graphene displayed good adsorption characteristic for CH4.

Carbon-Based Polymer Nanocomposites for Dye and Pigment Removal

Abstract This chapter discusses carbon-based polymer nanocomposites including carbon nanotubes, carbon nanofibers, graphene, graphene oxide, and reduced graphene oxide as filler elements in the nanocomposites for the removal of various dyes and pigments. The carbon-based nanocomposites are discussed in general followed by critical review of their performance on dye and pigment removal via adsorption, membrane separation, and photocatalytic processes in which the advantages and limitations of each processes are addressed. At the end of this chapter, the future direction of the application of these nanocomposites is also included.

Carbon-Based Polymer Nanocomposites as Electrolytes

Abstract Proton exchange membrane fuel cells (PEMFCs) have been extensively developed as a promising candidate as an alternative power source and for energy storage because of their zero emissions and high power density. Nafion is widely employed as an electrolyte due to several advantages if possesses. Nevertheless, the drawbacks of Nafion have drawn attention to developing alternative carbon-based polymers with high proton conductivity, excellent thermal and mechanical properties, and low cost. Among several approaches for the modification of carbon-based polymers, incorporating carbon-based polymers with nanocomposites has been found to be an effective way to elevate the fuel cell properties. These nanocomposites are not only able to overcome the limitations of carbon-based polymer but also enhanced the proton conductivity and improve the mechanical and thermal properties of the composite membrane. This review briefly discusses the effect of nanomaterials, particularly carbon-based nanomaterials, on the resultant PEMFC composite with respect to proton conductivity.

Performance of PES/LSMM-OGCN Photocatalytic Membrane for Phenol Removal: Effect of OGCN Loading

In designing a photocatalytic oxidation system, the immobilized photocatalyst technique becomes highly profitable due to its promising capability in treating organic pollutants such as phenols in wastewater. In this study, hydrophilic surface modifying macromolecules (LSMM) modified polyethersulfone (PES) hybrid photocatalytic membranes incorporated with oxygenated graphitic carbon nitride (OGCN) was successfully developed using phase inversion technique. The effectiveness of the hybrid photocatalytic membrane was determined under different loading of OGCN photocatalyst (0, 0.5, 1.0, 1.5, 2.0, and 2.5 wt%). The best amount of OGCN in the casting solution was 1.0 wt% as the agglomeration did not occur considering the stability of the membrane performance and morphology. The highest flux of 264 L/m2·h was achieved by PES/LSMM-OGCN1.5wt% membrane. However, the highest flux performance was not an advantage in this situation as the flux reduced the rejection value due to open pores. The membrane with the highest photocatalytic performance was obtained at 1.0 wt% of OGCN loading with 35.78% phenol degradation after 6 h. Regardless of the lower rejection value, the performance shown by the PES/LSMM-OGCN1.0wt% membrane was still competent because of the small difference of less than 1% to that of the PES/LSMM-OGCN0wt% membrane. Based on the findings, it can be concluded that the optimisation of the OGCN loading in the PES hybrid photocatalytic membrane indeed plays an important role towards enhancing the catalyst distribution, phenol degradation, and acceptable rejection above all considerations.

Photocatalytic degradation of oilfield produced water using graphitic carbon nitride embedded in electrospun polyacrylonitrile nanofibers

Separation and purification of oilfield produced water (OPW) is a major environmental challenge due to the co-production of the OPW during petroleum exploration and production operations. Effective capture of oil contaminant and its in-situ photodegradation is one of the promising methods to purify the OPW. Based on the photocatalytic capability of graphitic carbon nitride (GCN) which was recently rediscovered, photodegradation capability of GCN for OPW was investigated in this study. GCN was synthesized by calcination of urea and further exfoliated into nanosheets. The GCNs were incorporated into polyacrylonitrile nanofibers using electrospinning, which gave a liquid-permeable self-supporting photocatalytic nanofiber mat that can be handled by hand. The photocatalytic nanofiber demonstrated 85.4% degradation of OPW under visible light irradiation, and improved the degradation to 96.6% under UV light. Effective photodegradation of the photocatalytic nanofiber for OPW originates from synergetic effects of oil adsorption by PAN nanofibers and oil photodegradation by GCNs. This study provides an insight for industrial application on purification of OPW through photocatalytic degradation under solar irradiation.