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  1. Fulltext (E)-1-(2,4,6-Trihy-droxy-benzyl-idene)-4-ethyl-thio-semicarbazide dihydrate
    Shawish HB, Tan KW, Maah MJ, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2010;66(Pt 9):o2230.
    PMID: 21588600 DOI: 10.1107/S1600536810030783
    In the title mol-ecule, C(10)H(13)N(3)O(3)S·2H(2)O, the thio-semi-carbazide =N-NH-C(=S)-NH- fragment [torsion angle = 0.2 (1)°] is nearly coplanar with the benzene ring [dihedral angle = 2.4 (1)°]. The benzene ring and semicarbazide moiety are located on opposite sites of the C=N bond, showing an E configuration. The hy-droxy, imino and water H atoms are engaged in extensive hydrogen bonding, forming a three-dimensional network.
  2. Fulltext 5-Ethyl-5-methyl-4-phenyl-5H-1,2,4-triazol-3(4H)-thione
    Tan KW, Maah MJ, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2010;66(Pt 9):o2224.
    PMID: 21588595 DOI: 10.1107/S1600536810030503
    The five-membered ring of the title compound Δ(1)-1,2,4-triazoline-5-thione, C(11)H(13)N(3)S, is almost planar (r.m.s. deviation = 0.009 Å); the phenyl ring is aligned at 84.6 (2)° with respect to the five-membered ring. The crystal studied was a racemic twin with an approximate 20% minor twin component. Weak inter-molecular C-H⋯N hydrogen bonding is present in the crystal structure.
  3. A computational and experimental study on acoustic pressure for ultrasonically formed oil-in-water emulsion
    Tiong TJ, Chu JK, Lim LY, Tan KW, Hong Yap Y, Asli UA
    Ultrason Sonochem, 2019 Sep;56:46-54.
    PMID: 31101285 DOI: 10.1016/j.ultsonch.2019.03.026
    In the field of ultrasonic emulsification, the formation and cavitation collapse is one major factor contributing to the formation of micro- and nano-sized emulsion droplets. In this work, a series of experiments were conducted to examine the effects of varying the ultrasonic horn's position to the sizes of emulsion droplets formed, in an attempt to compare the influence of the simulated acoustic pressure fields to the experimental results. Results showed that the intensity of the acoustic pressure played a vital role in the formation of smaller emulsion droplets. Larger areas with acoustic pressure above the cavitation threshold in the water phase have resulted in the formation of smaller emulsion droplets ca. 250 nm and with polydispersity index of 0.2-0.3. Placing the ultrasonic horn at the oil-water interface has hindered the formation of small emulsion droplets, due to the transfer of energy to overcome the interfacial surface tension of oil and water, resulting in a slight reduction in the maximum acoustic pressure, as well as the total area with acoustic pressures above the cavitation threshold. This work has demonstrated the influence of the position of the ultrasonic horn in the oil and water system on the final emulsion droplets formed and can conclude the importance of generating acoustic pressure above the cavitation threshold to achieve small and stable oil-in-water emulsion.
  4. A rhodamine based chemosensor for solvent dependent chromogenic sensing of cobalt (II) and copper (II) ions with good selectivity and sensitivity: Synthesis, filter paper test strip, DFT calculations and cytotoxicity
    Chan WC, Saad HM, Sim KS, Lee VS, Ang CW, Yeong KY, et al.
    Spectrochim Acta A Mol Biomol Spectrosc, 2021 Jun 23;262:120099.
    PMID: 34198119 DOI: 10.1016/j.saa.2021.120099
    A new chemosensor 1 was synthesized by reacting rhodamine B hydrazide and 2,3,4-trihydroxybenzaldehyde, which was then characterized by spectroscopic techniques and single crystal X-ray crystallography. Sensor 1 has the ability to sense Co2+/Cu2+ ions by "naked-eye" with an apparent colour change from colourless to pink in different solvent system, MeCN and DMF respectively. Furthermore, it can selectively detect Co2+/Cu2+ among wide range of different metal ions, and it exhibits low detection limit of 4.425 × 10-8 M and 1.398 × 10-7 M respectively. Binding mode of the two complexes were determined to be 1:1 stoichiometry for Co2+ complex and 1:2 stoichiometry for Cu2+ complex through Job's plot, IR spectroscopy, mass spectrometry and 1H NMR spectroscopy. Moreover, reversibility of the sensor 1 as copper (II) ion detector was determined by using EDTA and the results showed that sensor 1 can be reused for at least 6 cycles. Other than that, a low cost chemosensor test strips were fabricated for the convenient "naked-eye" detection of Co2+ and Cu2+ in pure aqueous media. The MTT assay was conducted in order to determine the cytotoxicity of sensor 1 towards human cell lines.
  5. Fulltext An outbreak of methicillin-resistant Staphylococcus aureus in a neonatal intensive care unit in Singapore: a 20-month study of clinical characteristics and control
    Tan KW, Tay L, Lim SH
    Singapore Med J, 1994 Jun;35(3):277-82.
    PMID: 7997904
    Methicillin resistant Staphylococcus aureus (MRSA) is a major infection control problem in many countries. There have been many reports of outbreaks in neonatal nurseries including, in our part of the world, Australia, Hong Kong and Malaysia. A recent outbreak of MRSA in the neonatal intensive care unit in the Kandang Kerbau Hospital, Singapore, presented us with the opportunity to study the clinical characteristics of the outbreak and the effects of infection control measures. Neonates admitted to the neonatal intensive care unit were studied over a 20-month period. They were all screened for nasal colonisation on admission and weekly thereafter. Infections were documented. Over this period there were altogether 2,576 admissions of which 85 infants had nasal colonisation with MRSA (3.3%) and 28 developed infections (1%). Although the majority of infants colonised by MRSA suffered no ill effects, 3 had septicaemia and 2 had septicaemia with osteomyelitis. There were no deaths. Standard infection control measures with barrier nursing and the use of mupirocin nasal ointment were ineffective, and control was achieved only after strict cohorting together with the use of mupirocin was instituted. This was done without additional costs to the department and without additional nurses or doctors.
  6. Bilateral External Oblique Intercostal Catheter for Post-operative Analgesia After Open Pancreaticoduodenectomy: A Case Report
    Chan WK, Tan KW, Chong KP, Lim ACC, Khalid I
    Cureus, 2023 Oct;15(10):e47189.
    PMID: 38021569 DOI: 10.7759/cureus.47189
    Open pancreaticoduodenectomy, also known as Whipple surgery, is a complex and painful procedure that requires a multi-modal analgesic approach for successful post-operative rehabilitation and recovery. While thoracic epidural analgesia (TEA) remains the gold standard for pain relief after open upper abdominal surgery, it carries many risks that may outweigh the potential benefits of the technique. Furthermore, in laparoscopic converted to open pancreaticoduodenectomy cases, post-operative placement of a thoracic epidural catheter is inconvenient to the patient due to pain and positioning. The external oblique intercostal (EOI) block is a novel method that provides somatic analgesia to the upper abdomen. We present a case of bilateral EOI block with catheter insertion for post-operative analgesia in a patient who underwent laparoscopic converted to open Whipple surgery.
  7. Fulltext Bis[(4-chloro-benz-yl)triphenyl-phospho-nium] tetra-chloridozincate(II) trihydrate
    Tan KW, Maah MJ, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2010;66(Pt 6):m690.
    PMID: 21579329 DOI: 10.1107/S1600536810018325
    The crystal structure of the title compound, (C(25)H(21)ClP)(2)[ZnCl(4)]·3H(2)O, consists of tetra-hedral phosphonium cations and tetra-hedral zincate anions; the water mol-ecules form weak hydrogen bonds to the anions. Two of the water mol-ecules are disordered over three sites in a 0.68:0.55:0.77 ratio.
  8. Cavitation technology - a greener processing technique for the generation of pharmaceutical nanoemulsions
    Sivakumar M, Tang SY, Tan KW
    Ultrason Sonochem, 2014 Nov;21(6):2069-83.
    PMID: 24755340 DOI: 10.1016/j.ultsonch.2014.03.025
    Novel nanoemulsion-based drug delivery systems (DDS) have been proposed as alternative and effective approach for the delivery of various types of poorly water-soluble drugs in the last decade. This nanoformulation strategy significantly improves the cell uptake and bioavailability of numerous hydrophobic drugs by increasing their solubility and dissolution rate, maintaining drug concentration within the therapeutic range by controlling the drug release rate, and reducing systemic side effects by targeting to specific disease site, thus offering a better patient compliance. To date, cavitation technology has emerged to be an energy-efficient and promising technique to generate such nanoscale emulsions encapsulating a variety of highly potent pharmaceutical agents that are water-insoluble. The micro-turbulent implosions of cavitation bubbles tear-off primary giant oily emulsion droplets to nano-scale, spontaneously leading to the formation of highly uniform drug contained nanodroplets. A substantial body of recent literatures in the field of nanoemulsions suggests that cavitation is a facile, cost-reducing yet safer generation tool, remarkably highlighting its industrial commercial viability in the development of designing novel nanocarriers or enhancing the properties of existing pharmaceutical products. In this review, the fundamentals of nanoemulsion and the principles involved in their formation are presented. The underlying mechanisms in the generation of pharmaceutical nanoemulsion under acoustic field as well as the advantages of using cavitation compared to the conventional techniques are also highlighted. This review focuses on recent nanoemulsion-based DDS development and how cavitation through ultrasound and hydrodynamic means is useful to generate the pharmaceutical grade nanoemulsions including the complex double or submicron multiple emulsions.
  9. Colour detection thresholds in faces and colour patches
    Tan KW, Stephen ID
    Perception, 2013;42(7):733-41.
    PMID: 24344549
    Human facial skin colour reflects individuals' underlying health (Stephen et al 2011 Evolution & Human Behavior 32 216-227); and enhanced facial skin CIELab b* (yellowness), a* (redness), and L* (lightness) are perceived as healthy (also Stephen et al 2009a International Journal of Primatology 30 845-857). Here, we examine Malaysian Chinese participants' detection thresholds for CIELab L* (lightness), a* (redness), and b* (yellowness) colour changes in Asian, African, and Caucasian faces and skin coloured patches. Twelve face photos and three skin coloured patches were transformed to produce four pairs of images of each individual face and colour patch with different amounts of red, yellow, or lightness, from very subtle (deltaE = 1.2) to quite large differences (deltaE = 9.6). Participants were asked to decide which of sequentially displayed, paired same-face images or colour patches were lighter, redder, or yellower. Changes in facial redness, followed by changes in yellowness, were more easily discriminated than changes in luminance. However, visual sensitivity was not greater for redness and yellowness in nonface stimuli, suggesting red facial skin colour special salience. Participants were also significantly better at recognizing colour differences in own-race (Asian) and Caucasian faces than in African faces, suggesting the existence of cross-race effect in discriminating facial colours. Humans' colour vision may have been selected for skin colour signalling (Changizi et al 2006 Biology Letters 2 217-221), enabling individuals to perceive subtle changes in skin colour, reflecting health and emotional status.
  10. Copper complexes with phosphonium containing hydrazone ligand: topoisomerase inhibition and cytotoxicity study
    Chew ST, Lo KM, Lee SK, Heng MP, Teoh WY, Sim KS, et al.
    Eur J Med Chem, 2014 Apr 9;76:397-407.
    PMID: 24602785 DOI: 10.1016/j.ejmech.2014.02.049
    Four new copper(II) complexes containing phosphonium substituted hydrazone (L) with the formulations [CuL]Cl(3), [Cu(phen)L]Cl(4), [Cu(bpy)L]Cl(5), [Cu(dbpy)L]Cl(6), (where L = doubly deprotonated hydrazone; phen = 1,10'-phenanthroline; bpy = 2,2'-bipyridine; dbpy = 5,5'-dimethyl-2,2'-bipyridine) have been synthesized. The compounds were characterized by elemental analysis, spectroscopic methods and in the case of crystalline products by X-ray crystallography. The cytotoxicity and topoisomerase I (topo I) inhibition activities of these compounds were studied. It is noteworthy that the addition of N,N-ligands to the copper(II) complex lead to the enhancement in the cytotoxicity of the compounds, especially against human prostate adenocarcinoma cell line (PC-3). Complex 4 exhibits the highest activity against PC-3 with the IC₅₀ value of 3.2 μΜ. The complexes can also inhibit topo I through the binding to DNA and the enzyme.
  11. Crystal structure, DNA binding studies, nucleolytic property and topoisomerase I inhibition of zinc complex with 1,10-phenanthroline and 3-methyl-picolinic acid
    Seng HL, Von ST, Tan KW, Maah MJ, Ng SW, Rahman RN, et al.
    Biometals, 2010 Feb;23(1):99-118.
    PMID: 19787298 DOI: 10.1007/s10534-009-9271-y
    Crystal structure analysis of the zinc complex establishes it as a distorted octahedral complex, bis(3-methylpicolinato-kappa(2) N,O)(2)(1,10-phenanthroline-kappa(2) N,N)-zinc(II) pentahydrate, [Zn(3-Me-pic)(2)(phen)]x5H(2)O. The trans-configuration of carbonyl oxygen atoms of the carboxylate moieties and orientation of the two planar picolinate ligands above and before the phen ligand plane seems to confer DNA sequence recognition to the complex. It cannot cleave DNA under hydrolytic condition but can slightly be activated by hydrogen peroxide or sodium ascorbate. Circular Dichroism and Fluorescence spectroscopic analysis of its interaction with various duplex polynucleotides reveals its binding mode as mainly intercalation. It shows distinct DNA sequence binding selectivity and the order of decreasing selectivity is ATAT > AATT > CGCG. Docking studies lead to the same conclusion on this sequence selectivity. It binds strongly with G-quadruplex with human tolemeric sequence 5'-AG(3)(T(2)AG(3))(3)-3', can inhibit topoisomerase I efficiently and is cytotoxic against MCF-7 cell line.
  12. Fulltext Daily Consumption of a Fruit and Vegetable Smoothie Alters Facial Skin Color
    Tan KW, Graf BA, Mitra SR, Stephen ID
    PLoS One, 2015;10(7):e0133445.
    PMID: 26186449 DOI: 10.1371/journal.pone.0133445
    Consumption of dietary carotenoids or carotenoid supplements can alter the color (yellowness) of human skin through increased carotenoid deposition in the skin. As fruit and vegetables are the main dietary sources of carotenoids, skin yellowness may be a function of regular fruit and vegetable consumption. However, most previous studies have used tablets or capsules to supplement carotenoid intake, and less is known of the impact of increased fruit and vegetable consumption on skin color. Here, we examined skin color changes in an Asian population (Malaysian Chinese ethnicity) over a six week dietary intervention with a carotenoid-rich fruit smoothie. Eighty one university students (34 males, 47 females; mean age 20.48) were assigned randomly to consuming either a fruit smoothie (intervention group) or mineral water (control group) daily for six weeks. Participants' skin yellowness (CIELab b*), redness (a*) and luminance (L*) were measured at baseline, twice during the intervention period and at a two-week follow-up, using a handheld reflectance spectrophotometer. Results showed a large increment in skin yellowness (p<0.001) and slight increment in skin redness (p<0.001) after 4 weeks of intervention for participants in the intervention group. Skin yellowness and skin redness remained elevated at the two week follow up measurement. In conclusion, intervention with a carotenoid-rich fruit smoothie is associated with increased skin redness and yellowness in an Asian population. Changes in the reflectance spectrum of the skin suggest that this color change was caused by carotenoid deposition in the skin.
  13. Fulltext Diaqua-(1,4,8,11-tetra-aza-cyclo-tetra-decane-κN,N,N,N)copper(II) bis-(2,3,4,5,6-penta-fluoro-benzoate) dihydrate
    Ahmad Tajidi NS, Abdullah N, Arifin Z, Tan KW, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2010;66(Pt 8):m889.
    PMID: 21588134 DOI: 10.1107/S1600536810025705
    The Cu(II) atom in the title salt, [Cu(C(10)H(24)N(4))(H(2)O)(2)](C(6)F(5)CO(2))(2)·2H(2)O, is chelated by the four N atoms of the 1,4,8,11-tetra-aza-cyclo-tetra-decane (cyclam) ligand and is coordinated by two water mol-ecules in a Jahn-Teller-type tetra-gonally distorted octa-hedral geometry. The Cu(II) atom lies on a center of inversion. The cations, anions and uncoordinated water mol-ecules are linked by N-H⋯O and O-H⋯O hydrogen bonds, forming a layer structure parallel to (001).
  14. Fulltext Diaqua-(1,4,8,11-tetra-aza-cyclo-tetra-decane-κN,N,N,N)copper(II) bis-(4-methyl-benzoate) monohydrate
    Ahmad Tajidi NS, Abdullah N, Arifin Z, Tan KW, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2010;66(Pt 8):m890.
    PMID: 21588135 DOI: 10.1107/S1600536810026012
    The Cu(II) atom in the title salt, [Cu(C(10)H(24)N(4))(H(2)O)(2)](C(8)H(7)O(2))(2)·H(2)O, is chelated by the four N atoms of the 1,4,8,11-tetra-aza-cyclo-tetra-decane (cyclam) ligand and is coordinated by two water mol-ecules in a Jahn-Teller-type of tetra-gonally distorted octa-hedral geometry. The cations, anions and lattice water mol-ecules are linked by N-H⋯O and O-H⋯O hydrogen bonds to form a layer structure parallel to (001).
  15. Fulltext Diaqua-(1,4,8,11-tetra-aza-cyclo-tetra-decane-κN,N,N,N)copper(II) dideca-noate dihydrate
    Ahmad Tajidi NS, Abdullah N, Arifin Z, Tan KW, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2010;66(Pt 8):m888.
    PMID: 21588133 DOI: 10.1107/S1600536810025699
    The Cu(II) atom in the title salt, [Cu(C(10)H(24)N(4))(H(2)O)(2)][CH(3)(CH(2))(8)CO(2)](2)·2H(2)O, is chelated by the four N atoms of the 1,4,8,11-tetra-aza-cyclo-tetra-decane (cyclam) ligand and is coordinated by two water mol-ecules in a Jahn-Teller-type tetra-gonally distorted octa-hedral geometry. The Cu(II) atom lies on a center of inversion. The cations, anions and uncoordinated water mol-ecules are linked by N-H⋯O and O-H⋯O hydrogen bonds, forming a layer structure parallel to (001).
  16. Fulltext Diaqua-(1,4,8,11-tetra-aza-cyclo-tetra-decane-κN,N,N,N)copper(II) dihepta-noate dihydrate
    Ahmad Tajidi NS, Abdullah N, Arifin Z, Tan KW, Ng SW
    Acta Crystallogr Sect E Struct Rep Online, 2010;66(Pt 8):m887.
    PMID: 21588132 DOI: 10.1107/S1600536810025687
    The Cu(II) atom in the title salt, [Cu(C(10)H(24)N(4))(H(2)O)(2)][CH(3)(CH(2))(5)CO(2)](2)·2H(2)O, is chelated by the four N atoms of the 1,4,8,11-tetra-aza-cyclo-tetra-decane (cyclam) ligand and is coordinated by two water mol-ecules in a tetra-gonally Jahn-Teller-distorted octa-hedral geometry. The Cu(II) atom lies on a center of inversion. The cations, anions and uncoordinated water mol-ecules are linked by N-H⋯O and O-H⋯O hydrogen bonds, forming a layer structure parallel to (100). The alkyl chain of the anion is disordered over two positions in a 0.82 (1):0.18 (1) ratio.
  17. Fulltext Dinuclear and mononuclear metal(II) polypyridyl complexes against drug-sensitive and drug-resistant Plasmodium falciparum and their mode of action
    Lai JW, Maah MJ, Tan KW, Sarip R, Lim YAL, Ganguly R, et al.
    Malar J, 2022 Dec 17;21(1):386.
    PMID: 36528584 DOI: 10.1186/s12936-022-04406-0
    BACKGROUND: Malaria remains one of the most virulent and deadliest parasitic disease in the world, particularly in Africa and Southeast Asia. Widespread occurrence of artemisinin-resistant Plasmodium falciparum strains from the Greater Mekong Subregion is alarming. This hinders the national economies, as well as being a major drawback in the effective control and elimination of malaria worldwide. Clearly, an effective anti-malarial drug is urgently needed.

    METHODS: The dinuclear and mononuclear copper(II) and zinc(II) complexes were synthesized in ethanolic solution and characterized by various physical measurements (FTIR, CHN elemental analysis, solubility, ESI-MS, UV-Visible, conductivity and magnetic moment, and NMR). X-ray crystal structure of the dicopper(II) complex was determined. The in vitro haemolytic activities of these metal complexes were evaluated spectroscopically on B+ blood while the anti-malarial potency was performed in vitro on blood stage drug-sensitive Plasmodium falciparum 3D7 (Pf3D7) and artemisinin-resistant Plasmodium falciparum IPC5202 (Pf5202) with fluorescence dye. Mode of action of metal complexes were conducted to determine the formation of reactive oxygen species using PNDA and DCFH-DA dyes, JC-1 depolarization of mitochondrial membrane potential, malarial 20S proteasome inhibition with parasite lysate, and morphological studies using Giemsa and Hoechst stains.

    RESULTS: Copper(II) complexes showed anti-malarial potency against both Pf3D7 and Pf5202 in sub-micromolar to micromolar range. The zinc(II) complexes were effective against Pf3D7 with excellent therapeutic index but encountered total resistance against Pf5202. Among the four, the dinuclear copper(II) complex was the most potent against both strains. The zinc(II) complexes caused no haemolysis of RBC while copper(II) complexes induced increased haemolysis with increasing concentration. Further mechanistic studies of both copper(II) complexes on both Pf3D7 and Pf5202 strains showed induction of ROS, 20S malarial proteasome inhibition, loss of mitochondrial membrane potential and morphological features indicative of apoptosis.

    CONCLUSION: The dinuclear [Cu(phen)-4,4'-bipy-Cu(phen)](NO3)4 is highly potent and can overcome the total drug-resistance of Pf5202 towards chloroquine and artemisinin. The other three copper(II) and zinc(II) complexes were only effective towards the drug-sensitive Pf3D7, with the latter causing no haemolysis of RBC. Their mode of action involves multiple targets.

  18. Fulltext Editorial: Perceptions of People: Cues to Underlying Physiology and Psychology
    Sulikowski D, Tan KW, Jones AL, Welling LLM, Stephen ID
    Front Psychol, 2020;11:643.
    PMID: 32322229 DOI: 10.3389/fpsyg.2020.00643
  19. Fulltext Estimating direct and spill-over impacts of political elections on COVID-19 transmission using synthetic control methods
    Lim JT, Maung K, Tan ST, Ong SE, Lim JM, Koo JR, et al.
    PLoS Comput Biol, 2021 May;17(5):e1008959.
    PMID: 34043622 DOI: 10.1371/journal.pcbi.1008959
    Mass gathering events have been identified as high-risk environments for community transmission of coronavirus disease 2019 (COVID-19). Empirical estimates of their direct and spill-over effects however remain challenging to identify. In this study, we propose the use of a novel synthetic control framework to obtain causal estimates for direct and spill-over impacts of these events. The Sabah state elections in Malaysia were used as an example for our proposed methodology and we investigate the event's spatial and temporal impacts on COVID-19 transmission. Results indicate an estimated (i) 70.0% of COVID-19 case counts within Sabah post-state election were attributable to the election's direct effect; (ii) 64.4% of COVID-19 cases in the rest of Malaysia post-state election were attributable to the election's spill-over effects. Sensitivity analysis was further conducted by examining epidemiological pre-trends, surveillance efforts, varying synthetic control matching characteristics and spill-over specifications. We demonstrate that our estimates are not due to pre-existing epidemiological trends, surveillance efforts, and/or preventive policies. These estimates highlight the potential of mass gatherings in one region to spill-over into an outbreak of national scale. Relaxations of mass gathering restrictions must therefore be carefully considered, even in the context of low community transmission and enforcement of safe distancing guidelines.
  20. Evaluation of carbon-based nanosorbents synthesised by ethylene decomposition on stainless steel substrates as potential sequestrating materials for nickel ions in aqueous solution
    Lee XJ, Lee LY, Foo LP, Tan KW, Hassell DG
    J Environ Sci (China), 2012;24(9):1559-68.
    PMID: 23520862
    The present work covers the preparation of carbon-based nanosorbents by ethylene decomposition on stainless steel mesh without the use of external catalyst for the treatment of water containing nickel ions (Ni2+). The reaction temperature was varied from 650 to 850 degrees C, while reaction time and ethylene to nitrogen flow ratio were maintained at 30 min and 1:1 cm3/min, respectively. Results show that nanosorbents synthesised at a reaction temperature of 650 degrees C had the smallest average diameter (75 nm), largest BET surface area (68.95 m2/g) and least amount of impurity (0.98 wt.% Fe). A series of batch-sorption tests were performed to evaluate the effects of initial pH, initial metal concentration and contact time on Ni2+ removal by the nanosorbents. The equilibrium data fitted well to Freundlich isotherm. The kinetic data were best correlated to a pseudo second-order model indicating that the process was of chemisorption type. Further analysis by the Boyd kinetic model revealed that boundary layer diffusion was the controlling step. This primary study suggests that the prepared material with Freundlich constants compared well with those in the literature, is a promising sorbent for the sequestration of Ni2+ in aqueous solutions.
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