Hatijah Basri

Biophysical characteristics of cells cultured on cholesteryl ester liquid crystals

This study aimed at examining the biophysical characteristics of human derived keratinocytes (HaCaT) cultured on cholesteryl ester liquid crystals (CELC). CELC was previously shown to improve sensitivity in sensing cell contractions. Characteristics of the cell integrin expressions and presence of extracellular matrix (ECM) proteins on the liquid crystals were interrogated using various immunocytochemical techniques. The investigation was followed by characterization of the chemical properties of the liquid crystals (LC) after immersion in cell culture media using Fourier transform infrared spectroscopy (FTIR). The surface morphology of cells adhered to the LC was studied using atomic force microscopy (AFM). Consistent with the expressions of the integrins α2, α3 and β1, extracellular matrix proteins (laminin, collagen type IV and fibronectin) were found secreted by the HaCaT onto CELC and these proteins were also secreted by cells cultured on the glass substrates. FTIR analysis of the LC revealed the existence of spectrum assigned to cholesterol and ester moieties that are essential compounds for the metabolizing activities of keratinocytes. The immunostainings indicated that cell adhesion on the LC is mediated by self-secreted ECM proteins. As revealed by the AFM imaging, the constraint in cell membrane spread on the LC leads to the increase in cell surface roughness and thickness of cell membrane. The biophysical expressions of cells on biocompatible CELC suggested that CELC could be a new class of biological relevant material.

An acid functionalized MWCNT/PVP nanocomposite as a new additive for fabrication of an ultrafiltration membrane with improved anti-fouling resistance

Membrane fouling is one of the main challenges encountered in ultrafiltration (UF) processes and the use of nanoparticles for the improvement of UF performance is a recent trend in membrane technology. In this study, in order to improve surface characteristics of polyethersulfone (PES)-based membranes for greater resistance against biofouling, PES was incorporated with a new type of nanocomposite (NC) in which the NC could be synthesized by blending acid functionalized multiwalled carbon nanotubes (f-MWCNT) with polyvinylpyrrolidone (PVP) in dimethylformamide (DMF). The chemistry of the NCs embedded within the PES membrane matrix was analysed by FTIR, whereas the fabricated membranes were characterized by FESEM, contact angle, water absorption tests, surface profile studies and their filtration performances with respect to pure water permeation, antifouling resistance against proteins and flux recovery rate. The results revealed that, compared to the pristine PES membrane, the antifouling ability of the PES membrane incorporated with f-MWCNT/PVP NC is greater, recording 81.7% flux recovery and 80.2% total resistance (>76% were reversible one). The protein separation results indicated that, the NCs based membrane was able to reject 93.4%, 74.7%, 59.4% and 28.5% for bovine serum albumin (66 kDa), pepsin (34.6 kDa), trypsin (20 kDa) and (14.6 kDa), respectively.

Effects of water as non-solvent additive on performance of polysulfone ultrafiltration membrane

In this work, polysulfone ultrafiltration membranes were prepared via simple phase inversion with distilled water as non-solvent additive. The main reason for the addition of water in polysulfone dope solution preparation was to enhance the membranes structure. In the dope, 15 wt. % of polysulfone was used and water was varied up to 6 wt. %. The effects of water on morphology, porosity and tensile properties were investigated in detail. From the porosity test, results showed that the addition of water has improved membrane porosity up to 53 %. The FESEM images revealed that membrane morphology has also been modified. However, the tensile properties of membrane decreased as water content increased which may be due to the porosity interaction between polysulfone/NMP with water.

Performance Studies of Polysulfone-Based Membrane: Effect of Silica Morphology

In the present work, polysulfone (PSf) ultrafiltration membranes were prepared by solution casting. The effects of rice husk silica (RHS) on the surface properties of the PSf/Polyethylene glycol (PEG) membrane were observed and investigated. Characterizations were conducted to determine the membrane cross-section area and RHS distribution. The structure of RHS and morphology of membrane were analyzed by using X-ray diffractometer (XRD) and scanning electron microscope (SEM). XRD pattern showed that the amorphous silica was produced from rice husk ash (RHA). The analysis of SEM indicates that the addition of RHS obviously changed the microstructure of the membrane especially at top layer and sub layer.

Preparation and Characterization of Green Porous Palm Shell Based Activated Carbon by Two Step Chemical Activation Using KOH

The large quantity of agricultural waste materials that poses disposal challenge to our environment could be converted into useful products such as activated carbon (AC). Palm oil shell based porous AC was prepared by two step process using KOH as the chemical activant. Palm oil shell was carbonized at 800°C for 2 hours and activated using CO2 at same temperature for 1 hour which yield 23.27% fixed carbon. The AC was characterized by Langmuir surface area, BET surface area and pore volume of 410.7 m2/g, 350 m2/g and 0.2 cm3/g respectively, the FTIR analysis identified the presence of alkanes, carbonyls and hydroxyls as the main functional groups in the AC. Scanning electron microscopy images illustrates the gradual formation of pores from the precursor to the produced AC due to elimination of volatiles and contaminants in the material. However, the AC produced showed basic properties suitable for the removal of hydrophobic organic contaminants in water and wastewater.

Synthesis and Characterization of Low-Cost Porous Carbon from Palm Oil Shell via K2CO3 Chemical Activation Process

The abundant fraction of agricultural waste materials in the environment that poses disposal challenge could be converted into useful value added products such as activated carbon. Palm oil shell based carbon was prepared by two step process using K2CO3 as the chemical activant. The Langmuir surface area, BET surface area and pore volume were 817 m2/g, 707m2/g and 0.31cm3/g. From the FTIR analysis, carbonyls, alkenes and hydroxyls were identified. The SEM image shows gradual formation of pores due to elimination of volatiles and contaminants. Carbonization at 800°C for 2 hours and activation at same temperature for 1h has the highest yield of 23.27%. The proximate and ultimate analysis shows high percentage of carbon and low percentage of ash which is an indication of a good material for production of porous carbon. The activated carbon produced showed basic properties suitable for removal of organic contaminants in aqueous solutions. However, the aim of this study is to produce a green and porous carbon with controlled pores and surface properties for organic contaminants removal from water and wastewater.

Effects of calcination factors on the composite cathode powder LSCF-SDC carbonate by using dry milling

The effects of calcination factors on the La0.6Sr0.4Co0.2Fe0.8O3-δ-SDCC (LSCF-SDCC) composite cathodes powder were investigated. LSCF-SDCC has been prepared using high energy ball milling technique via dry milling method. The resultant LSCF-SDCC composite cathodes powder then were calcined at 700, 750 and 800 °C with soaking time of 1, 2 and 3 hours. The findings reveal that different calcinations temperature and soaking time gives effects to the composite cathodes powder. Clear peak intensity demonstrate from calcination temperature 750 °C as confirm via XRD analysis indicates that crystalline structure has been improved. FESEM investigation demonstrate the presence of large particles in the resultant powder resulting from the increased calcination temperature and soaking time. LSCF-SDCC composite cathodes powder calcined at a temperature of 750oC for soaking time 1, 2 and 3 hours demonstrates good crystallite structure to be served as composite cathode SOFCs compared to samples calcined at 700oC and 800oC with soaking time 1, 2 and 3 hours.

Modelling of cadmium (II) uptake from aqueous solutions using treated rice husk: Fixed - Bed studies

Rice husk is an agricultural waste material obtained mainly from rice mills. Treated rice husk was evaluated as a sorbent for cadmium (II) ions removal from solutions by utilising fixed-bed adsorption mode. In this study, the influence of flow rate (3 and 9 mL/min), adsorbent heights of (0.9, 1.8 and 2.8 cm) and influent cadmium ions concentration of (5 and 20 mg/L) on the sorption capacity of the adsorbent in a fixed-bed column were explored. The highest uptake of 87 % was obtained using 20 mg/L initial Cd (II) solution was achieved at high flow rate of 9 mL/min and a bed height of 2.8 cm. The experimental results obtained from the column adsorption studies were correlated with the Thomas, Yoon–Nelson and Adams–Bohart models. The modelling results for the adsorption indicated that the Adams–Bohart model fitted well over the other models.

Effects of Milling Techniques and Calcinations Temperature on the Composite Cathode Powder LSCF-SDC Carbonate

Composite cathode La0.6Sr0.4Co0.2Fe0.8O3-δ-SDC carbonates (LSCF-SDCC) for applications of low temperature solid oxide fuel cell (LTSOFC) were developed. LSCF-SDCC were mixed using high energy ball milling technique via dry and wet milling method followed by calcinations at 700, 750 and 800 °C. The findings reveal that different calcinations temperature and milling techniques gives effects to the composite cathodes powder. Clear peak intensity demonstrate from wet milling technique as confirm via XRD analysis indicates that crystalline structure has been improved. FESEM investigation demonstrate the presence of large particles in the resultant powder resulting from the increased calcination temperature. LSCF-SDCC composite cathodes powder produced via wet milling technique have good fine fraction and demonstrates good crystallite structure to be served as cathode of LTSOFC compared to dry milling technique.

Effect of operating condition on polysulfone/PEG/silica membrane fouling in wastewater separation

Adjustment of operation and membrane materials are key points to minimize the membrane fouling. Therefore, this study explored the effect of operating condition such as pH, wastewater, ionic strength, and membrane pressure on polysulfone/ silica. The study conducted using cross flow ultrafiltration membrane test rig. Optimization was done via Taguchi method (L9) using the larger the better signalto- noise (S/N) ratio. The best result were obtained at pH: 7, dilution of wastewater concentration at 75%, ionic strength: 0%, transmembrane pressure: 4 bar. Ionic strength was negligible in this study due to low signal ratio. The highest contribution in this study was found from membrane pressure as compared to other factors. Level of pH showed the lowest effect on membrane fouling.