Displaying publications 121 - 140 of 943 in total

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  1. Observation and explanation of two-dimensional interconversion of oximes with multiple heart-cutting using comprehensive multidimensional gas chromatography
    Kulsing C, Nolvachai Y, Wong YF, Glouzman MI, Marriott PJ
    J Chromatogr A, 2018 Apr 20;1546:97-105.
    PMID: 29548566 DOI: 10.1016/j.chroma.2018.02.035
    Real-time interconversion processes produce unconventional peak broadening in gas chromatography (GC), and can be used to generate kinetic and thermodynamic data. In this study, an unusual separation situation in comprehensive two dimensional GC where two dimensional interconversion (i.e. a raised plateau in both first and second dimension, 1D and 2D) was observed in analysis of oxime isomers. This resulted in a characteristic and unusual rectangular peak shape in the two dimensional result. A related theoretical approach was introduced to explain the peak shape supported by simulation results which can be varied depending on concentration profiles and kinetics of the process. The simulated results were supported by experimental results obtained by a comprehensive heart-cut multidimensional GC (H/C MDGC) approach which was developed to clearly investigate isomerisation of E/Z oxime molecules in both 1D and 2D separations under different isothermal conditions. The carrier gas flow and oven temperature were selected according to initial results for 1D interconversion on a poly(ethyleneglycol) stationary phase, which was further used in both 1D and 2D separations to result in broad zones of oxime interconversion in both dimensions. The method involved repetitive injections of oxime sample, then sampling contiguous fractions of sample into a long 2D column which is intended to promote considerable interconversion. Comprehensiveness arises from the fact that the whole sample is sampled from the 1D to the 2D column, with the long 2D column replacing the short 2D column used in classical comprehensive two-dimensional gas chromatography, where the latter will not promote sufficient interconversion. Data processing and presentation permits a 'rectangular' distribution corresponding to the separated compounds, characteristic of this experiment.
    Matched MeSH terms: Kinetics
  2. Growth and optimization of carbon nanotubes in powder activated carbon for an efficient removal of methylene blue from aqueous solution
    Alayan HM, Alsaadi MA, AlOmar MK, Hashim MA
    Environ Technol, 2019 Jul;40(18):2400-2415.
    PMID: 29451094 DOI: 10.1080/09593330.2018.1441911
    This work demonstrated the synthesis of carbon nanotubes (CNTs) on powder activated carbon (PAC) impregnated with Ni-catalyst through chemical vapour deposition. The optimized effects of reaction temperature, time and feedstock flow rates on CNT growth were examined. Potassium permanganate (KMnO4) and potassium permanganate in acidic solution (KMnO4/H2SO4) were used to functionalize CNTs samples. A primary screening of methylene blue (MB) adsorption was conducted. The chemical, physical and morphological properties of the adsorbent with the highest removal efficiency were investigated using FESEM, EDX, TEM, BET surface area, RAMAN, TGA, FTIR, and zeta potential. The resulting carbon nanotube-loaded activated carbons possessed abundant pore structure and large surface area. The MB removal by the as-synthesized CNTs was more remarkable than that by the modified samples. Adsorption studies were carried out to evaluate the optimum conditions, kinetics and isotherms for MB adsorption process. The response surface methodology-central composite design (RSM-CCD) was used to optimize the adsorption process parameters, including pH, adsorbent dosage and contact time. The investigation of the adsorption behaviour demonstrated that the adsorption was well fitted with the pseudo-second-order model and Langmuir isotherm with the maximum monolayer adsorption capacity of 174.5 mg/g. Meanwhile, the adsorption of MB onto adsorbent was driven by the electrostatic attraction and π-π interaction. Moreover, the as-obtained CNT-PAC exhibited good reusability after four repeated operations. In view of these empirical findings, the low-cost CNT-PAC has potential for removal of MB from aqueous solution.
    Matched MeSH terms: Kinetics
  3. Subcritical water extraction of low methoxyl pectin from pomelo (Citrus grandis (L.) Osbeck) peels
    Liew SQ, Teoh WH, Tan CK, Yusoff R, Ngoh GC
    Int J Biol Macromol, 2018 Sep;116:128-135.
    PMID: 29738869 DOI: 10.1016/j.ijbiomac.2018.05.013
    Low methoxyl (LM) pectin was extracted from pomelo peels using subcritical water in a dynamic mode. The effects of pressure and temperature were analyzed through a face-centred central composite design. Extraction yield and the rate of extraction were found to be predominantly influenced by temperature. Optimization of the subcritical water extraction (SWE) yielded an optimized operating condition of 120°C and 30bar with a predicted pectin yield of 18.8%. The corresponding experimental yield was 19.6%, which is in close agreement with the predicted data. The pectin obtained from the optimized condition was further analyzed for its physicochemical properties. The kinetics of the SWE was also evaluated whereby the one-site kinetic desorption model was found to be in good agreement with experimental data (R2>0.94).
    Matched MeSH terms: Kinetics
  4. Inhibition and kinetic studies of lignin degrading enzymes of Ganoderma boninense by naturally occurring phenolic compounds
    Surendran A, Siddiqui Y, Saud HM, Ali NS, Manickam S
    J Appl Microbiol, 2018 Sep;125(3):876-887.
    PMID: 29786938 DOI: 10.1111/jam.13922
    AIM: Lignolytic (lignin degrading) enzyme, from oil palm pathogen Ganoderma boninense Pat. (Syn G. orbiforme (Ryvarden)), is involved in the detoxification and the degradation of lignin in the oil palm and is the rate-limiting step in the infection process of this fungus. Active inhibition of lignin-degrading enzymes secreted by G. boninense by various naturally occurring phenolic compounds and estimation of efficiency on pathogen suppression was aimed at.

    METHODS AND RESULTS: In our work, 10 naturally occurring phenolic compounds were evaluated for their inhibitory potential towards the lignolytic enzymes of G. boninense. Additionally, the lignin-degrading enzymes were characterized. Most of the peholic compounds exhibited an uncompetitive inhibition towards the lignin-degrading enzymes. Benzoic acid was the superior inhibitor to the production of lignin-degrading enzymes, when compared between the 10 phenolic compounds. The inhibitory potential of the phenolic compounds towards the lignin-degrading enzymes are higher than that of the conventional metal ion inhibitor. The lignin-degrading enzymes were stable in a wide range of pH but were sensitive to higher temperature.

    CONCLUSION: The study demonstrated the inhibitor potential of 10 naturally occurring phenolic compounds towards the lignin-degrading enzymes of G. boninense with different efficacies.

    SIGNIFICANCE AND IMPACT OF THE STUDY: The study has shed a light towards a new management strategy to control basal stem rot disease in oil palm. It serves as a replacement for the existing chemical control.

    Matched MeSH terms: Kinetics
  5. Fulltext X-ray diffraction and TGA kinetic analyses for chemical looping combustion applications
    Tijani MM, Aqsha A, Mahinpey N
    Data Brief, 2018 Apr;17:200-209.
    PMID: 29876387 DOI: 10.1016/j.dib.2017.12.044
    Synthesis and characterization of supported metal-based oxygen carriers were carried out to provide information related to the use of oxygen carriers for chemical looping combustion processes. The Cu, Co, Fe, Ni metals supported with Al2O3, CeO2, TiO2, ZrO2 were prepared using the wetness impregnation technique. Then, the X-ray Diffraction (XRD) characterization of oxidized and reduced samples was obtained and presented. The kinetic analysis using Thermogravimetric analyzer (TGA) of the synthesized samples was conducted. The kinetics of reduction reaction of all samples were estimated and explained.
    Matched MeSH terms: Kinetics
  6. Kinetics and thermodynamic analysis in one-pot pyrolysis of rice hull using renewable calcium oxide based catalysts
    Gan DKW, Loy ACM, Chin BLF, Yusup S, Unrean P, Rianawati E, et al.
    Bioresour Technol, 2018 Oct;265:180-190.
    PMID: 29894912 DOI: 10.1016/j.biortech.2018.06.003
    Thermodynamic and kinetic parameters of catalytic pyrolysis of rice hull (RH) pyrolysis using two different types of renewable catalysts namely natural limestone (LS) and eggshells (ES) using thermogravimetric analysis (TG) approach at different heating rates of 10-100 K min-1 in temperature range of 323-1173 K are investigated. Catalytic pyrolysis mechanism of both catalysts had shown significant effect on the degradation of RH. Model free kinetic of iso-conversional method (Flynn-Wall-Ozawa) and multi-step reaction model (Distributed Activation Energy Model) were employed into present study. The average activation energy was found in the range of 175.4-177.7 kJ mol-1 (RH), 123.3-132.5 kJ mol-1 (RH-LS), and 96.1-100.4 kJ mol-1 (RH-ES) respectively. The syngas composition had increased from 60.05 wt% to 63.1 wt% (RH-LS) and 63.4 wt% (RH-ES). However, the CO2 content had decreased from 24.1 wt% (RH) to 20.8 wt% (RH-LS) and 19.9 wt% (RH-ES).
    Matched MeSH terms: Kinetics
  7. Fulltext The effect of Saccharin concentration on the electrochemical behaviour of electrodeposited Nanocrystalline Cobalt-Iron coating
    Nik Rozlin Nik Masdek, Wan Muhammad Aniq Aiman, Mardziah Che Murad, Zuraidah Salleh, Koay Mei Hyie
    Pertanika Journal of Science & Technology, 2017;25(103):191-200.
    MyJurnal
    In the electrodeposition system, adding saccharin alters the properties of the metal deposits by changing the electrode kinetics of the deposited surface. In this study, nanocrystalline cobalt-iron (CoFe) coating was synthesised using the electrodeposition technique with different saccharin concentrations. The results obtained showed that the coating thickness increased while the grain size decreased from 51 nm to 40 nm when the saccharin concentration increased from 0 to 2 g/L. The nanocrystalline CoFe coating produced with 2 g/L of saccharin concentration resulted in the smallest particle size of 71.22 nm and the highest microhardness of 251.86 HV. From the salt spray test (24 and 48 hours) it was found that the use of saccharin at higher concentration of 2 g/L improves the corrosion resistance of the nanocrystalline CoFe coating significantly due to the change of surface morphology as well as the decrease in grain size.
    Matched MeSH terms: Kinetics
  8. Fulltext The Effects of Leg Length Discrepancy on Stability and Kinematics-Kinetics Deviations: A Systematic Review
    Azizan NA, Basaruddin KS, Salleh AF
    Appl Bionics Biomech, 2018;2018:5156348.
    PMID: 30116295 DOI: 10.1155/2018/5156348
    Various studies have examined body posture stability, including postural sway and associated biomechanical parameters, to assess the severity effects of leg length discrepancy (LLD). However, various viewpoints have been articulated on the results of these studies because of certain drawbacks in the comprehensive analysis of the effect of variations in LLD magnitude. Therefore, this systematic review was performed to help focus on the current findings to help identify which biomechanical parameters are most relevant, commonly used, and able to distinguish and/or have specific clinical relevance to the effect of variations in LLD magnitude during static (standing) and dynamic (walking) conditions. Several electronic databases containing studies from the year 1983 to 2016 (Scopus, ScienceDirect, PubMed, PMC, and ProQuest) were obtained in our literature search. The search process yielded 22 published articles that fulfilled our criteria. We found most of the published data that we analyzed to be inconsistent, and very little data was obtained on the correlation between LLD severity and changes in body posture stability during standing and walking. However, the results of the present review study are in line with previous observational studies, which describe asymmetry in the lower limbs corresponding to biomechanical parameters such as gait kinematics, kinetics, and other parameters described during static (standing) postural balance. In future investigations, we believe that it might be useful to use and exploit other balance-related factors that may potentially influence body posture stability.
    Matched MeSH terms: Kinetics
  9. Fulltext Lunge as a sport-specific exercise: a mini review
    Ali Md Nadzalan, Muhammad Hannan Sazali, Mohamad Shahrul Azzfar
    Journal of Engineering and Science Research, 2018;2(1):6-10.
    MyJurnal
    As a way to enhance performance in sports, apart from in-field or in court training, athletes are recommended to adopt resistance training into their training routine. As an exercise that needs the performer to split their legs, lunge is suggested to be included as an exercise in a training session. Various researches had been conducted on lunge and several findings showed different methods or protocols of lunge affect the kinematics, kinetics muscle activation and fascicle behaviour response during the exercise. Although not much study conducted on the chronic adaptations, the existing studies suggested that performers should well plan the training protocols as this will cause different training adaptations.
    Matched MeSH terms: Kinetics
  10. Box-Behnken design to optimize the synthesis of new crosslinked chitosan-glyoxal/TiO2 nanocomposite: Methyl orange adsorption and mechanism studies
    Mohammad AT, Abdulhameed AS, Jawad AH
    Int J Biol Macromol, 2019 May 15;129:98-109.
    PMID: 30735780 DOI: 10.1016/j.ijbiomac.2019.02.025
    A crosslinked chitosan-glyoxal/TiO2 nanocomposite (CCG/TNC) was synthesized by loading different ratios of TiO2 nanoparticles into polymeric matrix of crosslinked chitosan-glyoxal (CCG) to be a promising biosorbent for methyl orange (MO). Box-Behnken design (BBD) in response surface methodology (RSM) was applied to optimize various process parameters, viz., loading of TiO2 nanoparticles into CCG polymeric matrix (A: 0%-50%), adsorbent dose (B: 0.04-0.14 g/50 mL), solution pH (C: 4-10), and temperature (D: 30-50 °C). The highest MO removal efficiency of 75.9% was observed by simultaneous interactions between AB, AC, and BC. The optimum TiO2 loading, adsorbent dosage, solution pH, and temperature were (50% TiO2: 50% chitosan labeled as CCG/TNC-50), 0.09 g/50 mL, 4.0, and 40 °C. The adsorption of MO from aqueous solution by using CCG/TNC-50 in batch mode was evaluated. The kinetic results were well described by the pseudo-first order kinetic, and the equilibrium data were in agreement with Langmuir isotherm model with maximum adsorption capacity of 416.1 mg/g. The adsorption mechanism included electrostatic attractions, n-π stacking interactions, dipole-dipole hydrogen bonding interactions, and Yoshida H-bonding.
    Matched MeSH terms: Kinetics
  11. High-performance porous biochar from the pyrolysis of natural and renewable seaweed (Gelidiella acerosa) and its application for the adsorption of methylene blue
    Ahmed MJ, Okoye PU, Hummadi EH, Hameed BH
    Bioresour Technol, 2019 Apr;278:159-164.
    PMID: 30685620 DOI: 10.1016/j.biortech.2019.01.054
    A high-performance porous biochar adsorbent prepared by facile thermal pyrolysis of seaweed (Gelidiella acerosa) is reported. The textural characteristics of the prepared seaweed biochar (SWBC) and the performance in the adsorption of methylene blue (MB) dye were evaluated. The batch experiment for the adsorption of MB was conducted under different parameters, such as temperature, pH, and initial concentration of MB in the range of 25-400 mg/L. The developed SWBC exhibited a relatively high surface area, average pore size, and pore volume of 926.39 m2/g, 2.45 nm, and 0.57 cm3/g, respectively. The high surface area and pristine mineral constituents of the biochar promoted a high adsorption capacity of 512.67 mg/g of MB at 30 °C. The adsorption isotherm and kinetics data best fitted the Langmuir and pseudo-second-order equations. The results indicate that SWBC is efficient for MB adsorption and could be a potential adsorbent for wastewater treatment.
    Matched MeSH terms: Kinetics
  12. A clean approach for functionalized carbon nanotubes by deep eutectic solvents and their performance in the adsorption of methyl orange from aqueous solution
    Ibrahim RK, El-Shafie A, Hin LS, Mohd NSB, Aljumaily MM, Ibraim S, et al.
    J Environ Manage, 2019 Apr 01;235:521-534.
    PMID: 30716672 DOI: 10.1016/j.jenvman.2019.01.070
    In this study two deep eutectic solvents (DESs) were prepared using ethylene glycol (EG) and two different ammonium-based salts. The potential of these DESs as novel agents for CNTs functionalization was examined by performing a comprehensive characterization study to identify the changes developing after the functionalization process. The impact of DESs was obvious by increasing the surface area of CNTs to reach 197.8 (m2/g), and by adding new functional groups to CNTs surface without causing any damage to the unique structure of CNTs. Moreover, CNTs functionalized with DESs were applied as new adsorbents for the removal of methyl orange (MO) from water. The adsorption conditions were optimized using RSM-CCD experimental design. The kinetics and the equilibrium adsorption data were analyzed using different kinetic and isotherm models. According to the regression results, adsorption kinetics data were well described by pseudo-second order model, whereas adsorption isotherm data were best represented by Langmuir isotherm model. The highest recorded maximum adsorption capacity (qmax) value was found to be 310.2 mg/g.
    Matched MeSH terms: Kinetics
  13. Adsorptive behaviour of palm oil mill sludge biochar pyrolyzed at low temperature for copper and cadmium removal
    Goh CL, Sethupathi S, Bashir MJ, Ahmed W
    J Environ Manage, 2019 May 01;237:281-288.
    PMID: 30802752 DOI: 10.1016/j.jenvman.2018.12.103
    In this work, the influence of pyrolysis temperature on the physicochemical properties of palm oil mill sludge biochar (POSB) and its adsorption properties towards cadmium (Cd) and copper (Cu) was investigated. Characterization experiments suggested that POSBs' surface functional groups play the major role in the adsorption process. POSB pyrolyzed at 400 °C showed the best characteristics for Cu and Cd removal. Adsorption study indicated that contact time and shaking speed enhances the adsorption capacity of POSB. It was affirmed that pH adjustment is not necessary for POSB to adsorb Cu and Cd. Mechanism studies fitted well with Langmuir and Pseudo-Second Order model. Thermodynamic parameters indicated that the adsorption was spontaneous, endothermic and correspond to chemical adsorption. The highest uptakes of Cu and Cd were recorded at 48.8 mg/g and 46.2 mg/g respectively. This work verifies that the temperature used for palm oil mill sludge (POS) pyrolysis and adsorption condition played the most prominent role in Cu and Cd removal from aqueous solutions.
    Matched MeSH terms: Kinetics
  14. Properties of immobilized Candida Antarctica lipase B on highly macroporous copolymer
    Handayani N, Achmad S, Miletic N, Loos K, Wahyuningrum D
    Sains Malaysiana, 2011;40.
    In spite of their excellent catalytic properties, enzymes should be improved before their implementation both in industrial and laboratorium scales. Immobilization of enzyme is one of the ways to improve their properties. Candida antarctica lipase B (Cal-B) has been reported in numerous publications to be a particularly useful enzyme catalizing in many type of reaction including regio- and enantio- synthesis. For this case, cross-linking of immobilized Cal-B with 1,2,7,8 diepoxy octane is one of methods that proved significantly more stable from denaturation by heat, organic solvents, and proteolysis than lyophilized powder or soluble enzymes. More over, the aim of this procedure is to improve the activity and reusability of lipase. Enzyme kinetics test was carried out by transesterification reaction between 4-nitrophenyl acetate (pNPA) and methanol by varying substrate concentrations, and the result is immobilized enzymes follows the Michaelis-Menten models and their activity is match with previous experiment. Based on the Vmax values, the immobilized enzymes showed higher activity than the free enzyme. Cross-linking of immobilized lipase indicate that cross-linking by lower concentration of cross-linker, FIC (immobilized lipase that was incubated for 24 h) gave the highest activity and cross-linking by higher concentration of cross-linker, PIC (immobilized lipase that was incubated for 2 h) gives the highest activity. However, pore size and saturation level influenced their activity.
    Matched MeSH terms: Kinetics
  15. Equilibrium, kinetic and thermodynamic study of pesticides removal from water using novel glucamine-calix[4]arene functionalized magnetic graphene oxide
    Nodeh HR, Kamboh MA, Wan Ibrahim WA, Jume BH, Sereshti H, Sanagi MM
    Environ Sci Process Impacts, 2019 Apr 17;21(4):714-726.
    PMID: 30869668 DOI: 10.1039/c8em00530c
    A novel nanocomposite of MGO-NGC, composed of magnetic Fe3O4 nanoparticles (M), graphene oxide (GO), and N-methyl-d-glucamine functionalized calix[4]arene (NGC), was synthesized and applied as an effective adsorbent for the removal of two selected pesticides, namely hexaconazole and chlorpyrifos from water samples. The adsorbent was characterized by FTIR, SEM, EDX, TEM, and XRD. The main parameters affecting the adsorption process such as adsorbent dosage, pH of sample solution, salt effect, pesticide concentration, and adsorption time were investigated. The data from kinetic studies fitted well to the pseudo-second order kinetic model with R2 > 0.99. Among the isotherm models of Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich, the Langmuir isotherm fitted well to the adsorption process and demonstrated the monolayer adsorption pattern of the pesticides. Moreover, high adsorption capacities of 78.74 and 93.46 mg g-1 were obtained for chlorpyrifos and hexaconazole, respectively. Thermodynamic and free energy data indicated the physisorption mechanism for the adsorption process. The new adsorbent can be employed as an efficient, environment friendly, and highly reusable alternative for the removal of chlorinated pesticides from aqueous media.
    Matched MeSH terms: Kinetics
  16. Fulltext The adsorption of reactive orange 16 and basic blue 3 from aqueous solution using quaternized blue swimmer crab carapace
    Chuah, Y.J., Tan, Y.P., Abdullah, H.A.
    Pertanika Journal of Science & Technology, 2018;26(4):2045-2062.
    MyJurnal
    The crab carapace is a waste which cannot be decomposed. This waste was used to
    remove the Reactive Orange 16 (RO16) and Basic Blue 3 (BB3) from aqueous solution
    at different operational parameters such as pH, mass load, the concentrations of dye and
    the temperature. The crab collected was modified to obtain quaternized crab (QC) using
    (3-chloro-2-hydroxypropyl) trimethylammonium chloride solution (C6H15Cl2NO, 65% w/w
    in water). The pH of the dyes solution was varied from pH 4 to 10. The highest adsorption
    percentage was achieved at pH 7 for both dyes. Increasing the QC mass for the adsorption
    process had granted an increase of dyes removal percentage. The highest adsorption
    percentage was achieved at 91.00% for RO16 and 29.40% for BB3 dyes with 7.5 g/L QC
    used. However, the adsorption capacity of QC decreased with higher QC mass because the
    dye molecules occupied on the surface and prevented other molecules to diffuse into the
    QC. At higher concentration beyond 20 mg/L and 10 mg/L of RO16 and BB3, respectively,
    the maximum adsorption was achieved at 2.5362 mg/g and 0.6812 mg/g. The adsorption of
    both dyes by QC was best fitted using Langmuir isotherm model, explaining the adsorption
    mainly occurred as a single layer on the surface of QC. Comparison to the results obtained
    from the kinetic models, the adsorption was
    chemisorption in nature. According to the
    thermodynamic studies, the adsorption of
    RO16 was an exothermic, while BB3 was
    an endorthermic process.
    Matched MeSH terms: Kinetics
  17. Absorption, distribution and elimination behaviours of cadmium treated by in vitro DIN from WLP residue using SAAM II modeling
    Yasmin Mohd Idris Perama, Nur Shahidah Abdul Rashid, Syazwani Mohd Fadzil, Khoo Kok Siong
    Sains Malaysiana, 2018;47:611-618.
    Mathematically, the human alimentary tract organs were simplified in the model structure as separate compartments with
    pathways of transfer that are kinetically homogenous and equally distributed. The development of gastro-compartment
    model follows the first order kinetics of differential equations to describe cadmium absorption, distribution and elimination
    in the human digestive system. With the aid of in vitro DIN assay, an artificial gastric and gastrointestinal fluid were
    prepared using water leach purification (WLP) residue as a sample that contained toxic metals cadmium. The Simulation,
    Analysis and Modelling II (SAAM II) V2.1 software is employed to design models easily, simulate experiments quickly and
    analyze data accurately. Based on the experimental inputs and fractional transfer rates parameter incorporated to the
    gastro-compartment model, the concentration of cadmium against time profile curves were plotted as the model output.
    The curve presented concentration of cadmium in both gastric and gastrointestinal fluid where initially absorption phase
    (first hour) occurred followed by the distribution phase (second to third hours) and elimination process (third to fifth
    hours). The concentration of cadmium obtained from the simulated model structures was in good agreement with the
    fitted model predicted measurements as statistical t-test conducted showed the values were not significantly different.
    Therefore, modeling approach with SAAM II software gave realistic and better estimation of cadmium dissolution into
    the human gastrointestinal tract.
    Matched MeSH terms: Kinetics
  18. Adsorption of heavy metal ions on surface of functionalized oil palm empty fruit bunch fibers: single and binary systems
    Mohd Shaiful Sajab, Chin HC, Sarani Zakaria, Mika Sillanpaa
    Sains Malaysiana, 2017;46:157-165.
    The functionalization of surface charges on oil palm empty fruit bunch (EFB) fibers was modified by grafted carboxylic
    acid and polymer amine groups. Single and binary adsorption of Cu(II), Ni(II), Mo(VI) and As(V) were investigated
    by competitiveness in the adsorbents. The mechanism of each metal ion was deliberately studied on kinetics-diffusion
    (intraparticle diffusion) and isotherm adsorption models (Langmuir and Freundlich). Competitiveness of metal ions was
    found in the selectivity of Cu(II) > Ni(II) and Mo(VI) > As(V) in the binary solution. The regeneration of adsorbents
    was performed up to five cycles of an adsorption/desorption process and the reduction of adsorption performance was
    less than 14.5%. Therefore, this promises low-cost adsorbents for metal ion uptake, showing potential for removal and
    recovery in industrial wastewater treatment.
    Matched MeSH terms: Kinetics
  19. Catalytic pyrolysis of Chlorella vulgaris: Kinetic and thermodynamic analysis
    Fong MJB, Loy ACM, Chin BLF, Lam MK, Yusup S, Jawad ZA
    Bioresour Technol, 2019 Oct;289:121689.
    PMID: 31252316 DOI: 10.1016/j.biortech.2019.121689
    In the present study, catalytic pyrolysis of Chlorella vulgaris biomass was conducted to analyse the kinetic and thermodynamic performances through thermogravimetric approach. HZSM-5 zeolite, limestone (LS), bifunctional HZSM-5/LS were used as catalysts and the experiments were heated from 50 to 900 °C at heating rates of 10-100 °C/min. Iso-conversional model-free methods such as Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), Starink's, and Vyazovkin (V) were employed to evaluate the kinetic parameters meanwhile the thermodynamic parameters were determined by using FWO and KAS methods. The calculated EA values of non-catalytic and catalytic pyrolysis of HZSM-5 zeolite, LS, and bifunctional HZSM-5/LS were determined to be in the range of 156.16-158.10 kJ/mol, 145.26-147.84 kJ/mol, 138.81-142.06 kJ/mol, and 133.26 kJ/mol respectively. The results have shown that catalytic pyrolysis with the presence of bifunctional HZSM-5/LS resulted to a lower average EA and ΔH compared to HZSM-5, and LS which indicated less energy requirement in the process.
    Matched MeSH terms: Kinetics
  20. Storage stability and degradation kinetics of bioactive compounds in red palm oil microcapsules produced with solution-enhanced dispersion by supercritical carbon dioxide: A comparison with the spray-drying method
    Lee WJ, Tan CP, Sulaiman R, Hee YY, Chong GH
    Food Chem, 2020 Jan 30;304:125427.
    PMID: 31494501 DOI: 10.1016/j.foodchem.2019.125427
    Solution-enhanced dispersion by supercritical carbon dioxide (SEDS) and spray drying (SD) were used to microencapsulate red palm oil (RPO) to prolong the functionality of carotenes and vitamin E. The protective effects provided by SEDS and SD were evaluated in terms of the oxidative stability (65 °C for 35 days), fatty acid compositions, color change and degradation kinetics of carotenes and vitamin E (25 °C, 45 °C, 65 °C, and 85 °C for up to 198 days). SEDS microcapsules (SEDS-M) were the most oxidatively stable (total oxidation (Totox): 26.5), followed by SD microcapsules (SD-M) (34.9) and RPO (56.7). Degradation of carotenes and vitamin E fitted well a first-order kinetic model (average absolute relative deviation = 2-16%). SEDS-M offered better protection to vitamin E (Ea = 36 kJ/mol), whereas SD-M provided better protection for α + β carotene (Ea = 29 kJ/mol). Overall, encapsulation protected RPO during storage, with SEDS-microencapsulated RPO performing better than SD-microencapsulated RPO.
    Matched MeSH terms: Kinetics
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