Displaying publications 1 - 20 of 66 in total

  1. Bhatia S, Kohli S
    Br Dent J, 2020 12;229(12):760-761.
    PMID: 33339909 DOI: 10.1038/s41415-020-2516-4
  2. Mashitah, Zulfadhly Z, Bhatia S
    PMID: 10595446
    Non-living biomass of Pycnoporus sanguineus has an ability to take up lead,copper and cadmium ions from an aqueous solution. The role played by various functional groups in the cell wall and the mechanism uptake of lead, copper and cadmium by Pycnoporus sanguineus were investigated. Modification of the functional groups such as lipids, carboxylic and amino was done through chemical pretreatment in order to study their role in biosorption of metal ions. Results showed that the chemical modification of these functional groups has modified the ability of biomass to remove lead, copper and cadmium ions from the solution. Scanning electron microscopy was also used to study the morphological structure of the biomass before and after adsorption. The electron micrograph indicated that the structure of biomass changed due to the adsorption of the metals onto the cell walls. Furthermore, the X-ray energy dispersion analysis (EDAX) showed that the calcium ion present in the cell wall of biomass was released and replaced by lead ions. This implied that an ion exchange is one of the principal mechanisms for metal biosorption.
  3. Mashitah, Zulfadhly Z, Bhatia S
    Artif Cells Blood Substit Immobil Biotechnol, 1999 Sep-Nov;27(5-6):429-33.
    PMID: 10595444
    The equilibrium sorption capacity of a macro-fungi, Pycnoporus sanguineus biomass was studied using a single-metal system comprising copper ions. The rate and extent for the removal of copper were subjected to environmental parameters such as pH, biomass loading, temperature, and contact time. Results showed that the uptake of copper increased as the pH increased. However, as the biomass loading increased, the amount of metal uptake decreased. Instead, temperature does not have a significant effect on the metal uptake, especially between 30 to 40 degrees C. A maximum adsorption of copper ions was also observed within 15 minutes of reaction time for the entire sample tested. Furthermore, pre-treatment with sodium bicarbonate and boiling water significantly improved the sorption capacity of copper by Pycnoporus sanguineus.
  4. Kohli S, Bhatia S
    Biomed J, 2015 May-Jun;38(3):244-9.
    PMID: 25355393 DOI: 10.4103/2319-4170.143519
    Proper function, esthetics, and cost are the prime factors to be considered while selecting bridge veneering materials. The purpose of the study is to evaluate color durability of acrylic veneer materials after immersion in common beverages at different time intervals.
  5. Chew TL, Bhatia S
    Bioresour Technol, 2008 Nov;99(17):7911-22.
    PMID: 18434141 DOI: 10.1016/j.biortech.2008.03.009
    In Malaysia, there has been interest in the utilization of palm oil and oil palm biomass for the production of environmental friendly biofuels. A biorefinery based on palm oil and oil palm biomass for the production of biofuels has been proposed. The catalytic technology plays major role in the different processing stages in a biorefinery for the production of liquid as well as gaseous biofuels. There are number of challenges to find suitable catalytic technology to be used in a typical biorefinery. These challenges include (1) economic barriers, (2) catalysts that facilitate highly selective conversion of substrate to desired products and (3) the issues related to design, operation and control of catalytic reactor. Therefore, the catalytic technology is one of the critical factors that control the successful operation of biorefinery. There are number of catalytic processes in a biorefinery which convert the renewable feedstocks into the desired biofuels. These include biodiesel production from palm oil, catalytic cracking of palm oil for the production of biofuels, the production of hydrogen as well as syngas from biomass gasification, Fischer-Tropsch synthesis (FTS) for the conversion of syngas into liquid fuels and upgrading of liquid/gas fuels obtained from liquefaction/pyrolysis of biomass. The selection of catalysts for these processes is essential in determining the product distribution (olefins, paraffins and oxygenated products). The integration of catalytic technology with compatible separation processes is a key challenge for biorefinery operation from the economic point of view. This paper focuses on different types of catalysts and their role in the catalytic processes for the production of biofuels in a typical palm oil and oil palm biomass-based biorefinery.
  6. Chew TL, Bhatia S
    Bioresour Technol, 2009 May;100(9):2540-5.
    PMID: 19138514 DOI: 10.1016/j.biortech.2008.12.021
    Catalytic cracking of crude palm oil (CPO) and used palm oil (UPO) were studied in a transport riser reactor for the production of biofuels at a reaction temperature of 450 degrees C, with residence time of 20s and catalyst-to-oil ratio (CTO) of 5 gg(-1). The effect of HZSM-5 (different Si/Al ratios), beta zeolite, SBA-15 and AlSBA-15 were studied as physically mixed additives with cracking catalyst Rare earth-Y (REY). REY catalyst alone gave 75.8 wt% conversion with 34.5 wt% of gasoline fraction yield using CPO, whereas with UPO, the conversion was 70.9 wt% with gasoline fraction yield of 33.0 wt%. HZSM-5, beta zeolite, SBA-15 and AlSBA-15 as additives with REY increased the conversion and the yield of organic liquid product. The transport riser reactor can be used for the continuous production of biofuels from cracking of CPO and UPO over REY catalyst.
  7. Tamunaidu P, Bhatia S
    Bioresour Technol, 2007 Dec;98(18):3593-601.
    PMID: 17208441
    Oil palm is widely grown in Malaysia. Palm oil has attracted the attention of researchers to develop an 'environmentally friendly' and high quality fuel, free of nitrogen and sulfur. In the present study, the catalytic cracking of palm oil to biofuel was studied over REY catalyst in a transport riser reactor at atmospheric pressure. The effect of reaction temperature (400-500 degrees C), catalyst/palm oil ratio (5-10) and residence time (10-30s) was studied over the yield of bio-gasoline and gas as fuel. Design of experiments was used to study the effect of operating variables over conversion of palm oil and yield of hydrocarbon fuel. The response surface methodology was used to determine the optimum value of the operating variables for maximum yield of bio-gasoline fraction in the liquid product obtained.
  8. Ahmad AL, Ismail S, Bhatia S
    Environ Sci Technol, 2005 Apr 15;39(8):2828-34.
    PMID: 15884382
    The coagulation-flocculation process incorporated with membrane separation technology will become a new approach for palm oil mill effluent (POME) treatment as well as water reclamation and reuse. In our current research, a membrane pilot plant has been used for POME treatment where the coagulation-flocculation process plays an important role as a pretreatment process for the mitigation of membrane fouling problems. The pretreated POME with low turbidity values and high water recovery are the main objectives to be achieved through the coagulation-flocculation process. Therefore, treatment optimization to serve these purposes was performed using jar tests and applying a response surface methodology (RSM) to the results. A 2(3) full-factorial central composite design (CCD) was chosen to explain the effect and interaction of three factors: coagulant dosage, flocculent dosage, and pH. The CCD is successfully demonstrated to efficiently determine the optimized parameters, where 78% of water recovery with a 20 NTU turbidity value can be obtained at the optimum value of coagulant dosage, flocculent dosage, and pH at 15 000 mg/L, 300 mg/L, and 6, respectively.
  9. Kohli S, Bhatia S
    Eur J Prosthodont Restor Dent, 2016 12;24(4):170.
    PMID: 28510369 DOI: 10.1922/EJPRD_01650kohli01
    Sir, I write in regard to Nayar S et al article 'The Effect of a Radiation Positioning Stent (RPS) in the Reduction of Radiation Dosage to the Opposing Jaw and Maintenance of Mouth opening after Radiation Therapy'. I wholeheartedly agree to that patients undergoing radio-therapy who had an Radiation Positioning Stent (RPS) would show a significant reduction in radiation dosage to the opposing jaw and maintained their mouth opening in the short-term. As we know that oral cancer has emerged to be one of most deadliest cancer nowadays.
  10. Yus Azila Y, Mashitah MD, Bhatia S
    Bioresour Technol, 2008 Dec;99(18):8549-52.
    PMID: 18599293 DOI: 10.1016/j.biortech.2008.03.056
    A central composite design (CCD) was employed to optimize the biosorption of Pb(II) ions onto immobilized cells of Pycnoporus sanguineus. The independent variables were initial Pb(II) concentration, pH and biomass loading. The combined effects of these variables were analyzed by response surface methodology (RSM) using quadratic model for predicting the optimum point. Under these conditions the model predicted a maximum of 97.7% of Pb(II) ions removal at pH 4, 200mg/L of initial Pb(II) concentration with 10g/L of biosorbent. The experimental values are in good agreement with predicted values within +0.10 to +0.81% error.
  11. Mashitah MD, Yus Azila Y, Bhatia S
    Bioresour Technol, 2008 Jul;99(11):4742-8.
    PMID: 17981460
    Biosorption of cadmium (II) ions from aqueous solution onto immobilized cells of Pycnoporus sanguineus (P. sanguineus) was investigated in a batch system. Equilibrium and kinetic studies were conducted by considering the effect of pH, initial cadmium (II) concentration, biomass loading and temperature. Results showed that the uptake of cadmium (II) ions increased with the increase of initial cadmium (II) concentration, pH and temperature. Langmuir, Freundlich and Redlich-Peterson isotherm models were used to analyze the equilibrium data at different temperatures. Langmuir isotherm model described the experimental data well followed by Redlich-Peterson and Freundlich isotherm models. Biosorption kinetics data were fitted using pseudo-first, pseudo-second-order and intraparticle diffusion. It was found that the kinetics data fitted well the pseudo-second-order followed by intraparticle diffusion. Thermodynamic parameters such as standard Gibbs free energy (Delta G0), standard enthalpy (Delta H0) and standard entropy (Delta S0) were evaluated. The result showed that biosorption of cadmium (II) ions onto immobilized cells of P. sanguineus was spontaneous and endothermic nature.
  12. Zulfadhly Z, Mashitah MD, Bhatia S
    Environ Pollut, 2001;112(3):463-70.
    PMID: 11291452
    The ability of Pycnoporus sanguineus to adsorb heavy metals from aqueous solution was investigated in fixed-bed column studies. The experiments were conducted to study the effect of important design parameters such as column bed height, flow rate and initial concentration of solution. The breakthrough profiles were obtained in these studies. A mathematical model based on external mass transfer and pore diffusion was used for the prediction of mass transfer coefficient and effective diffusivity of metals in macro-fungi bed. Experimental breakthrough profiles were compared with the simulated breakthrough profiles obtained from the mathematical model. Bed Depth Service Time (BDST) model was used to analyse the experimental data and evaluated the performance of biosorption column. The BDST model parameters needed for the design of biosorption columns were evaluated for lead, copper and cadmium removal in the column. The columns were regenerated by eluting the metal ions using 0.1 M hydrochloric acid solution after the adsorption studies. The columns were subjected to repeated cycles of adsorption of same metal ions and desorption to evaluate the removal efficiency after adsorption-desorption.
  13. Taufiqurrahmi N, Mohamed AR, Bhatia S
    Bioresour Technol, 2011 Nov;102(22):10686-94.
    PMID: 21924606 DOI: 10.1016/j.biortech.2011.08.068
    The catalytic cracking of waste cooking palm oil to biofuel was studied over different types of nano-crystalline zeolite catalysts in a fixed bed reactor. The effect of reaction temperature (400-500 °C), catalyst-to-oil ratio (6-14) and catalyst pore size of different nanocrystalline zeolites (0.54-0.80 nm) were studied over the conversion of waste cooking palm oil, yields of Organic Liquid Product (OLP) and gasoline fraction in the OLP following central composite design (CCD). The response surface methodology was used to determine the optimum value of the operating variables for maximum conversion as well as maximum yield of OLP and gasoline fraction, respectively. The optimum reaction temperature of 458 °C with oil/catalyst ratio=6 over the nanocrystalline zeolite Y with pore size of 0.67 nm gave 86.4 wt% oil conversion, 46.5 wt% OLP yield and 33.5 wt% gasoline fraction yield, respectively. The experimental results were in agreement with the simulated values within an experimental error of less than 5%.
  14. Fan MS, Abdullah AZ, Bhatia S
    ChemSusChem, 2011 Nov 18;4(11):1643-53.
    PMID: 22191096
    A series of bimetallic catalysts containing nickel supported over MgO-ZrO2 were tested for activity in the dry reforming of carbon dioxide. A nickel-cobalt bimetallic catalyst gave the best performance in terms of conversion and coke resistance from a range of Ni-X bimetallic catalysts, X=Ca, K, Ba, La, and Ce. The nitrogen-adsorption and hydrogen-chemisorption studies showed the Ni-Co bimetallic supported catalyst to have good surface area with high metal dispersion. This contributed to the high catalytic activity, in terms of conversion activity and stability of the catalyst, at an equimolar methane/carbon dioxide feed ratio. The kinetics of methane dry reforming are studied in a fixed-bed reactor over an Ni-Co bimetallic catalyst in the temperature range 700-800 °C by varying the partial pressures of CH4 and CO2. The experimental data were analyzed based on the proposed reaction mechanism using the Langmuir-Hinshelwood kinetic model. The activation energies for methane and carbon dioxide consumption were estimated at 52.9 and 48.1 kJ mol(-1), respectively. The lower value of CO2 activation energy compared to the activation energy of CH4 indicated a higher reaction rate of CO2, which owes to the strong basicity of nanocrystalline support, MgO-ZrO2.
  15. Hashim SM, Mohamed AR, Bhatia S
    Adv Colloid Interface Sci, 2010 Oct 15;160(1-2):88-100.
    PMID: 20813344 DOI: 10.1016/j.cis.2010.07.007
    There has been tremendous progress in membrane technology for gas separation, in particular oxygen separation from air in the last 20 years. It provides an alternative route to the existing conventional separation processes such as cryogenic distillation and pressure swing adsorption as well as cheaper production of oxygen with high purity. This review presents the recent advances of ceramic membranes for the separation of oxygen from air at high temperature. It covers the issues and problems with respect to the selectivity and separation performance. The paper also presents different approaches applied to overcome these challenges. The future directions of ceramic-based membranes for oxygen separation from air are also presented.
  16. Sim JH, Kamaruddin AH, Bhatia S
    Bioresour Technol, 2010 Dec;101(23):8948-54.
    PMID: 20675129 DOI: 10.1016/j.biortech.2010.07.039
    The objective of this research is to investigate the potential of transesterification of crude palm oil (CPO) to biodiesel at 30 degrees C. The mass transfer limitations problem crucial at 30 degrees C due to the viscosity of CPO has been addressed. The process parameters that are closely related to mass transfer effects like enzyme loading, agitation speed and reaction time were optimized. An optimum methanol to oil substrate molar ratio at 6.5:1 was observed and maintained throughout the experiments. The optimum operating condition for the transesterification process was found at 6.67 wt% of enzyme loading and at 150 rpm of agitation speed. The corresponding initial reaction and FAME yield obtained at 6 h were 89.29% FAME yield/hr and 85.01%, respectively. The 85% FAME yield obtained at 30 degrees C operation of CPO transesterification shows that the process is potentially feasible for the biodiesel synthesis.
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