Displaying publications 161 - 180 of 896 in total

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  1. 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
  2. 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
  3. 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
  4. 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
  5. 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
  6. 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
  7. 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
  8. Valorization of Technical Lignin for the Production of Desirable Resins with High Substitution Rate and Controllable Viscosity
    Pang B, Lam SS, Shen XJ, Cao XF, Liu SJ, Yuan TQ, et al.
    ChemSusChem, 2020 Sep 07;13(17):4446-4454.
    PMID: 32118355 DOI: 10.1002/cssc.202000299
    The valorization of lignin to replace phenol is significant in the production of phenolic resins. However, a great challenge is to produce lignin-based resin (LR) with a suitable viscosity and high substitution rate of lignin to phenol. In this study, LRs were produced using hardwood technical lignin derived from the pulping industry. Structural analysis of the LRs indicated that the unsubstituted para and ortho carbon atoms of the aromatic ring influenced the curing temperature and activation energy of the resins. The curing kinetics and thermal decomposition study implied that urea and methylene groups in cured LRs were significant factors that affected the thermal stability negatively. The prepared LRs showed desirable features if used as adhesives to make plywood. This is the first approach in which a substitution rate of up to 65 % is achieved for low-reactive-site hardwood lignin, which provides a solution to the challenge of the simultaneous realization of the high addition of lignin and the adaptive viscosity of resins.
    Matched MeSH terms: Kinetics
  9. New efficient chitosan derivative for Cu(II) ions removal: Characterization and adsorption performance
    Sutirman ZA, Rahim EA, Sanagi MM, Abd Karim KJ, Wan Ibrahim WA
    Int J Biol Macromol, 2020 Jun 15;153:513-522.
    PMID: 32142849 DOI: 10.1016/j.ijbiomac.2020.03.015
    A new crosslinked chitosan grafted with methyl methacrylate (M-CTS) adsorbent was synthesized via free radical polymerization for effective removal of Cu(II) ions from aqueous solution. Crosslinked chitosan (1 g) was grafted with 29.96 × 10-1 M methyl methacrylate in the presence of 2.63 × 10-1 M ammonium persulfate as initiator at 60 °C for 2 h to give grafting and yield percentages of 201% and 67%, respectively. Batch adsorption experiment was performed as a function of solution pH, initial metal ion concentration and contact time. The isotherm data were adequately described by Langmuir model, while kinetic study revealed that the pseudo-second order rate model best fitted for the experimental data. The maximum adsorption capacity for M-CTS at pH 4 was 192.31 mg g-1. Furthermore, the reusability of over six adsorption-desorption cycles suggested that M-CTS is a durable adsorbent and good candidate for metal ions treatment.
    Matched MeSH terms: Kinetics
  10. 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
  11. 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
  12. 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
  13. 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
  14. Characterization of slowly-biodegradable organic compounds and hydrolysis kinetics in tropical wastewater for biological nitrogen removal
    How SW, Sin JH, Wong SYY, Lim PB, Mohd Aris A, Ngoh GC, et al.
    Water Sci Technol, 2020 Jan;81(1):71-80.
    PMID: 32293590 DOI: 10.2166/wst.2020.077
    Many developing countries, mostly situated in the tropical region, have incorporated a biological nitrogen removal process into their wastewater treatment plants (WWTPs). Existing wastewater characteristic data suggested that the soluble chemical oxygen demand (COD) in tropical wastewater is not sufficient for denitrification. Warm wastewater temperature (30 °C) in the tropical region may accelerate the hydrolysis of particulate settleable solids (PSS) to provide slowly-biodegradable COD (sbCOD) for denitrification. This study aimed to characterize the different fractions of COD in several sources of low COD-to-nitrogen (COD/N) tropical wastewater. We characterized the wastewater samples from six WWTPs in Malaysia for 22 months. We determined the fractions of COD in the wastewater by nitrate uptake rate experiments. The PSS hydrolysis kinetic coefficients were determined at tropical temperature using an oxygen uptake rate experiment. The wastewater samples were low in readily-biodegradable COD (rbCOD), which made up 3-40% of total COD (TCOD). Most of the biodegradable organics were in the form of sbCOD (15-60% of TCOD), which was sufficient for complete denitrification. The PSS hydrolysis rate was two times higher than that at 20 °C. The high PSS hydrolysis rate may provide sufficient sbCOD to achieve effective biological nitrogen removal at WWTPs in the tropical region.
    Matched MeSH terms: Kinetics
  15. Influence of parameters and radical scavengers on the visible-light-induced degradation of ciprofloxacin in ZnO/SnS2 nanocomposite suspension: Identification of transformation products
    Makama AB, Salmiaton A, Choong TSY, Hamid MRA, Abdullah N, Saion E
    Chemosphere, 2020 Aug;253:126689.
    PMID: 32304862 DOI: 10.1016/j.chemosphere.2020.126689
    Removal of ciprofloxacin (CIP) pollutant from wastewater using conventional process is particularly challenging due to poor removal efficiency. In this work, CIP was photocatalytically degraded using a porous ZnO/SnS2 photocatalyst prepared via microwaves. The influence of process parameters (e.g., pH, catalyst mass and initial CIP concentration) and radical scavengers on visible-light induced degradation of CIP on the catalyst was investigated. From the study, it was found that visible-light induced degradation of CIP on ZnO/SnS2 is a surface-mediated process and the reaction kinetics followed the Langmuir-Hinshelwood first-order kinetics. It was found that the optimum condition for CIP degradation was at pH of 6.1 and catalyst dosage of 500 mg L-1. Higher catalyst dosage however led to a decline in reaction rate due to light scattering effect and reduction in light penetration.
    Matched MeSH terms: Kinetics
  16. 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
  17. 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
  18. 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
  19. Dosimetric features and kinetic parameters of a glass system dosimeter
    Mhareb MHA, Alajerami YSM, Alqahtani M, Alshahri F, Saleh N, Alonizan N, et al.
    Luminescence, 2020 Jun;35(4):525-533.
    PMID: 31883298 DOI: 10.1002/bio.3761
    Lithium borate (LB) glasses doped with dysprosium oxide (Dy2 O3 ) have been prepared by utilizing the conventional melt-quench technique. The prepared glass samples were exposed to 60 Co to check their dosimetric features and kinetic parameters. These features involve glow curves, annealing, fading, reproducibility, minimum detectable dose (MDD), and effective atomic number (Zeff ). Kinetic parameters including the frequency factors and activation energy were also determined using three methods (glow curve analysis, initial rise, and peak shape method) and were thoroughly interpreted. In addition, the incorporation of Dy impurities into LB enhanced the thermoluminescence sensitivity ~170 times. The glow from LB:Dy appeared as a single prominent peak at 190°C. The best annealing proceeding was obtained at 300°C for 30 min. Signal stability was reported for a period of 1 and 3 months with a reduction of 26% and 31%, respectively. The proposed glass samples showed promising dosimeter properties that can be recommended for personal radiation monitoring.
    Matched MeSH terms: Kinetics
  20. Facile synthesis of xanthan biopolymer integrated 3D hierarchical graphene oxide/titanium dioxide composite for adsorptive lead removal in wastewater
    Lai KC, Lee LY, Hiew BYZ, Thangalazhy-Gopakumar S, Gan S
    Bioresour Technol, 2020 Aug;309:123296.
    PMID: 32330800 DOI: 10.1016/j.biortech.2020.123296
    Xanthan integrated graphene oxide functionalized by titanium dioxide was successfully prepared through facile, eco-friendly and cost effective ice-templating technique. The three-dimensional (3D) graphene composite demonstrated relatively high temperature stability, chemical functionalities and porous sponge-like structure. The adsorption of lead was favored by high initial concentration and shaking speed at the operational solution pH. The process equilibrium and kinetic adhered to the Langmuir and pseudo-second-order correlations, respectively. The biomass integrated graphene composite showed maximum adsorption capacities ranging from 132.18 to 199.22 mg/g for 30-70 °C. Moreover, it was highly regenerable under mild conditions (0.1 M hydrochloric acid, 30 °C) and used repeatedly while retaining 84.78% of its initial adsorption capacity at the fifth adsorption-regeneration cycle. With comparatively high lead adsorption capacities, adequate recyclability and environmentally friendliness, the as-prepared 3D graphene composite has high application potential in heavy metal-wastewater separation for protection of the environment and human health.
    Matched MeSH terms: Kinetics
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