Hasrinah Hasbullah

Antifouling polyethersulfone hemodialysis membranes incorporated with poly (citric acid) polymerized multi-walled carbon nanotubes

Poly (citric acid)-grafted-MWCNT (PCA-g-MWCNT) was incorporated as nanofiller in polyethersulfone (PES) to produce hemodialysis mixed matrix membrane (MMM). Citric acid monohydrate was polymerized onto the surface of MWCNTs by polycondensation. Neat PES membrane and PES/MWCNTs MMMs were fabricated by dry-wet spinning technique. The membranes were characterized in terms of morphology, pure water flux (PWF) and bovine serum albumin (BSA) protein rejection. The grafting yield of PCA onto MWCNTs was calculated as 149.2%. The decrease of contact angle from 77.56° to 56.06° for PES/PCA-g-MWCNTs membrane indicated the increase in surface hydrophilicity, which rendered positive impacts on the PWF and BSA rejection of the membrane. The PWF increased from 15.8Lm(-2)h(-1) to 95.36Lm(-2)h(-1) upon the incorporation of PCA-g-MWCNTs due to the attachment of abundant hydrophilic groups that present on the MWCNTs, which have improved the affinity of membrane towards the water molecules. For protein rejection, the PES/PCA-g-MWCNTs MMM rejected 95.2% of BSA whereas neat PES membrane demonstrated protein rejection of 90.2%. Compared to commercial PES hemodialysis membrane, the PES/PCA-g-MWCNTs MMMs showed less flux decline behavior and better PWF recovery ratio, suggesting that the membrane antifouling performance was improved. The incorporation of PCA-g-MWCNTs enhanced the separation features and antifouling capabilities of the PES membrane for hemodialysis application.

Tapioca starch biocomposite for disposable packaging ware

Tapioca Starch Biocomposite for Disposable Packaging Ware Roshafima R. Ali*, Wan A. W. A. Rahman, Rafiziana M. Kasmani, Norazana Ibrahim, Siti N. H. Mustapha, Hasrinah Hasbullah Department of Polymer Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia. Gas Engineering Department, FPREE, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia. roshafima@cheme.utm.my

Development of biocompatible and safe polyethersulfone hemodialysis membrane incorporated with functionalized multi-walled carbon nanotubes

A novel approach in the design of a safe, high performance hemodialysis membrane is of great demand. Despite many advantages, the employment of prodigious nanomaterials in hemodialysis membrane is often restricted by their potential threat to health. Hence, this work focusses on designing a biocompatible polyethersulfone (PES) hemodialysis membrane embedded with poly (citric acid)-grafted-multi walled carbon nanotubes (PCA-g-MWCNTs). Two important elements which could assure the safety of the nanocomposite membrane, i.e. (i) dispersion stability and (ii) leaching of MWCNTs were observed. The results showed the improved dispersion stability of MWCNTs in water and organic solvent due to the enriched ratio of oxygen-rich groups which subsequently enhanced membrane separation features. It was revealed that only 0.17% of MWCNTs was leached out during the membrane fabrication process (phase inversion) while no leaching was detected during permeation. In terms of biocompatibility, PES/PCA-g-MWCNT nanocomposite membrane exhibited lesser C3 and C5 activation (189.13 and 5.29ng/mL) and proteins adsorption (bovine serum albumin=4.5μg/cm2, fibrinogen=15.95μg/cm2) as compared to the neat PES membrane, while keeping a normal blood coagulation time. Hence, the PES/PCA-g-MWCNT nanocomposite membrane is proven to have the prospect of becoming a safe and high performance hemodialysis membrane.

Hemocompatibility evaluation of poly(1,8-octanediol citrate) blend polyethersulfone membranes

In this study, poly (1,8-octanediol citrate) (POC) was used to modify polyethersulfone (PES)-based membrane to enhance its hemocompatibility. Different compositions of POC (0-3%) were added into the polyethersulfone (PES) dope solutions and polyvinylpyrrolidone (PVP) was used as pore forming agent. The hemocompatible POC modified PES membranes were fabricated through phase-inversion technique. The prepared membranes were characterized using attenuated total reflectance-Fourier transform infrared (ATR-FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), Atomic-force microscopy (AFM), contact angle, Zeta-potential, membrane porosity and pore size and pure water flux (PWF) and BSA rejection. The hemocompatibility of the modified PES membranes was evaluated by human serum fibrinogen (FBG) protein adsorption, platelet adhesion, activated partial thromboplastin time (APTT) and prothrombin time (PT), and thrombin-antithrombin III (TAT), complement (C3a and C5a) activation and Ca2+ absorption on membrane. Results showed that by increasing POC concentration, FBG adsorption was reduced, less platelets adhesion, prolonged APTT and PT, lower TAT, C5a and C3a activation and absorb more Ca2+ ion. These results indicated that modification of PES with POC has rendered improved hemocompatibility properties for potential application in the field of blood purification, especially in hemodialysis.

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

Biodegradable Gas Separation Membrane Preparation by Manipulation of Casting Parameters

Poly(lactic acid) PLA that derived from renewable resources can help our society to reduce the dependence to non-renewable fossil resources. When come to human contact, this polymer and its degradation product are neither toxic nor carcinogenic to human body. The use of poly(lactic acid) (PLA), a biodegradable polymer, as a membrane material would assist the reduction of depending to petroleum-based polymer that will assist in disposal issues on non-biodegradable polymer. This study investigated the effect of evaporation time to the gas separation performance of PLA membrane. Membrane prepared from polymer solution consists of PLA and dichloromethane (DCM) as solvent was fabricated using pneumatically controlled casting system with dry/wet phase inversion method. Permeation test was conducted using pure oxygen and nitrogen gas. The results revealed that as the evaporation time increased, the pore size and surface porosity decreased, while the skin layer thickness increased. Although the morphology of the prepared membranes showed the desirable structure, the gas separation performance of the membrane prepared with polymer concentration of 15 wt% and 60s evaporation time was found to be promising but not yet commercially ready.

The Effect of Catalyst Loading (ni-ce/al2o3) on Coconut Copra Pyrolysis via Thermogravimetric Analyzer

The aim of this study is to investigate the influence of catalyst weight loading on pyrolysis of coconut copra via thermogravimetric analyser (TGA). The pyrolysis process is conducted up to 700 °C at a heating rate of 10 °C/min in nitrogen (N2) atmosphere flowing at 150 mL/min. The catalyst was successfully prepared via wet impregnation method, with alumina (Al2O3) used as support, while cerium (Ce) and nickel (Ni) act as promoter. The feedstock samples for TGA were prepared accordingly with biomass to catalyst weight loading ratio as follows: CC-1 (1 : 0.05), CC-2 (1 : 0.10), CC-3 (1 : 0.15), CC-4 (1 : 0.20), CC-5 (1 : 0.50), and CC-6 (1 : 1). For comparison, the pyrolysis of coconut copra without catalyst is also determined at the same operating condition and labelled as CC-7 (1 : 0). The TGA-DTG curves shows that, the presences of catalyst significantly affect the degradation rate of volatile matter than lignin degradation. In this study, the CC-3 sample has achieved high mass loss at 83.27 % and also high degradation rate at 0.0107 mg/s. For lignin decomposition, it shows that, CC-1 to CC-6 samples has achieved lignin mass loss percentage below 12.7 %. The non-catalytic sample (CC-7) has exhibited 80.33 % of volatile matter of mass loss and 13.92 % of lignin mass loss. The optimum catalyst loading was observed at 1 : 0.15 (CC-3) that work best to degrade volatile matter at highest mass loss, in which attributes to higher yield of pyrolysis oil.

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.

Design and Fabrication of Bench-Scale Flash Pyrolysis Reactor for Bio-Fuel Production

The purpose of this paper is to present the construction and testing of a bench-scale flash pyrolysis reactor for bio fuel production from local biomasses such as empty fruit bunches (EFB) and rice husk. The reactor is intended for a mobile application where it can be brought into the fields. The design is based on ablative reactor technology so that larger feed size can be processed. The moving rotor is equipped with helical strips to create optimum centrifugal and mechanical force inside the system. In order to provide a sustainable heat source, the resulting syngas is burned and recycled back into the reactor. This reactor will operate with reactor temperature ranges from 450 to 600 °C, 300 - 1,000 °C/s heating rates and 5 - 20 g/min biomass processing capacity. This study can provide an important basis in designing a mobile fast pyrolysis reactor for Malaysia’s biomass which in general consists of higher cellulose content