Farhana Aziz

Development of Polysulfone (PSF)-Carbon Molecular Sieve (CMS) Mixed Matrix Membrane (MMM) For O2/N2 Gas Separation

Mixed matrix membranes (MMMs) comprising polysulfone (PSF) Udel® P‐1700 and synthesized carbon molecular sieve (CMS) particles (<25 μm) have been fabricated and characterized. CMS were synthesized by using polyacrylonitrile (PAN) as polymer precursor. The casting process was performed at the processing temperature close to Tg of PSF in order to maintain the flexibility of polymer during film formation. This study investigated the effects of CMS loadings (10, 20, 30 and 35 wt%) on the morphology and the gas separation performance of PSF‐CMS MMMs. The fabricated MMMs were characterized using TGA, DSC, FESEM and single gas permeation test using high purity O2 and N2. Based on FESEM micrograph, a good polymer‐sieve adhesion was achieved in MMMs using the combination of PSF‐CMS even at high sieve loading (up to 35 wt%). The formation of ‘sieve‐in‐the‐cage’ morphology in PSF‐CMS MMMs has been minimized to a great extend by implementing casting procedure at the operating temperature close to the Tg of polymer ma...

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.

Graft copolymerization of acrylonitrile onto recycled newspapers cellulose pulp

The extraction of recycled newspapers (RNP) cellulose pulp began by a series of chemical alkali extraction, 5 wt% NaOH at 125°C for 2 h. Subsequently, the bleaching of alkalized pulp was carried out by using 2 wt% NaClO2 solutions in the presence of 60 wt% of nitric acid, for 4 h at 100°C. The graft copolymerization of acrylonitrile onto the bleached cellulose pulp was initiated by using ceric ammonium nitrate. The grafting conditions were optimized by varying the ceric ammonium nitrate (CAN) initiator concentration, acrylonitrile (ACN) concentration and reaction time. The successfully of the grafting process were determined by calculating the grafting yield (%GY) and grafting efficiency (%GE). The morphological and chemical structure of resulting grafted and ungrafted recycled newspaper cellulose pulp were characterized by using scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy.The extraction of recycled newspapers (RNP) cellulose pulp began by a series of chemical alkali extraction, 5 wt% NaOH at 125°C for 2 h. Subsequently, the bleaching of alkalized pulp was carried out by using 2 wt% NaClO2 solutions in the presence of 60 wt% of nitric acid, for 4 h at 100°C. The graft copolymerization of acrylonitrile onto the bleached cellulose pulp was initiated by using ceric ammonium nitrate. The grafting conditions were optimized by varying the ceric ammonium nitrate (CAN) initiator concentration, acrylonitrile (ACN) concentration and reaction time. The successfully of the grafting process were determined by calculating the grafting yield (%GY) and grafting efficiency (%GE). The morphological and chemical structure of resulting grafted and ungrafted recycled newspaper cellulose pulp were characterized by using scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy.

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.

Carbon-Based Polymer Nanocomposite for Photovoltaic Devices

Abstract In this chapter, an overview of the applications of carbon-based polymer nanocomposites for photovoltaic applications is presented. The structures and properties of carbon-based materials are properly introduced. The available methods to prepare carbon-based polymer nanocomposites such as solution mixing, melt blending and melt processing, and in situ polymerization are extensively discussed. In addition, the discussions are also focused on the physical properties of carbon-based polymer nanocomposites. Additionally, the applications of carbon-based polymer nanocomposites in the electrode and active layer of PV devices are also described. The future outlook of carbon-based polymer nanocomposite studies are also discussed to further broaden the perspective of this technology.

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.

The morphology effect on the selectivity of SPEEK/ENR membranes for direct methanol fuel cell

The objective of this study is to investigate the morphology effect of ENR-50 content on the conductivity and methanol permeability of SPEEK/ENR-50 membranes for DMFC application. Three different ratios (9.5:0.5, 8.5:1.5 and 7.5:2.5) of blended SPEEK/ENR-50 membranes were prepared via solution intercalation method. The cross sectional images of the all SPEEK/ENR-50 membranes studied by SEM shows an existence of ENR-50 droplets in SPEEK matrix which decrease in size with an increasing of ENR-50 content from 1.5 wt% to 2.5 wt%. The study of the performances of the blended membranes shows that the proton conductivity and methanol permeability of the membranes decrease with an increasing of ENR-50 content. However, the proton conductivity of the blended membrane with 0.5 wt% ENR-50 content (9.66x10-3 S cm-1) proven higher than pristine SPEEK but lower than Nafion 117. The barrier performance of all SPEEK/ENR-50 membranes was enhanced compared to the expensive Nafion 117 membrane and pristine SPEEK. Consequently, by incorporating ENR-50 content into SPEEK membrane, the selectivity of the membranes has considerably increased.

Pengaruh suhu karbonisasi kepada pembangunan membran karbon dengan kesan pemisahan gas CO2/CH4 yang cemerlang

In this study, P84 - based carbon tubular membranes were fabricated and characterized in terms of their structural morphology and gas permeation properties, by using Scanning Electron Microscopy (SEM) and pure gas permeation system, respectively. The polymer tubular membranes were then carbonized under nitrogen atmosphere at different carbonization temperatures of 600, 700, 800 and 900 °C, with heating rate of 3°C/min and thermal soak time of 30 minutes. The manipulation of carbonization temperatures was requ ired to see if it could enhance the permeation properties as desired. Pure gas permeation tests were performed using CO 2 and CH 4 gases. The CO 2 /CH 4 selectivity was found increasing as the carbonization temperature was increased from 600 to 800 °C. The carb on membrane carbonized at 800°C showed the most promising result for CO 2 /CH 4 selectivity, rendering 69.48 and CO 2 permeance of 206.1 GPU.