Displaying publications 1 - 20 of 99 in total

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  1. Metal(loid) Analysis of Commercial Rice from Malaysia using ICP-MS: Potential Health Risk Evaluation
    Navaretnam R, Hassan HN, Isa NM, Aris AZ, Looi LJ
    Environ Sci Pollut Res Int, 2023 Aug;30(37):87695-87720.
    PMID: 37423935 DOI: 10.1007/s11356-023-28459-z
    Rice is a predominant staple food in many countries. It is a great source of energy but can also accumulate toxic and trace metal(loid)s from the environment and pose serious health hazards to consumers if overdosed. This study aims to determine the concentration of toxic metal(loid)s [arsenic (As), cadmium (Cd), nickel (Ni)] and essential metal(loid)s [iron (Fe), selenium (Se), copper (Cu), chromium (Cr), cobalt (Co)] in various types of commercially available rice (basmati, glutinous, brown, local whites, and fragrant rice) in Malaysia, and to assess the potential human health risk. Rice samples were digested following the USEPA 3050B acid digestion method and the concentrations of metal(loid)s were analyzed using an inductively coupled plasma mass spectrometry (ICP-MS). Mean concentrations (mg/kg as dry weight) of metal(loid)s (n=45) across all rice types were found in the order of Fe (41.37)>Cu (6.51)>Cr (1.91)>Ni (0.38)>As (0.35)>Se (0.07)>Cd (0.03)>Co (0.02). Thirty-three percent and none of the rice samples surpassed, respectively, the FAO/WHO recommended limits of As and Cd. This study revealed that rice could be a primary exposure pathway to toxic metal(loid)s, leading to either noncarcinogenic or carcinogenic health problems. The non-carcinogenic health risk was mainly associated with As which contributed 63% to the hazard index followed by Cr (34%), Cd (2%), and Ni (1%). The carcinogenic risk to adults was high (>10-4) for As, Cr, Cd, and Ni. The cancer risk (CR) for each element was 5 to 8 times higher than the upper limit of cancer risk for an environmental carcinogen (<10-4). The findings from this study could provide the metal(loid)s pollution status of various types of rice which are beneficial to relevant authorities in addressing food safety and security-related issues.
    Matched MeSH terms: Cobalt/analysis
  2. Eco-friendly fabrication of nonenzymatic electrochemical sensor based on cobalt/polymelamine/nitrogen-doped graphitic-porous carbon nanohybrid material for glucose monitoring in human blood
    Elancheziyan M, Prakasham K, Eswaran M, Duraisamy M, Ganesan S, Lee SL, et al.
    Environ Res, 2023 Apr 15;223:115403.
    PMID: 36754108 DOI: 10.1016/j.envres.2023.115403
    The design and development of eco-friendly fabrication of cost-effective electrochemical nonenzymatic biosensors with enhanced sensitivity and selectivity are one of the emerging area in nanomaterial and analytical chemistry. In this aspect, we developed a facile fabrication of tertiary nanocomposite material based on cobalt and polymelamine/nitrogen-doped graphitic porous carbon nanohybrid composite (Co-PM-NDGPC/SPE) for the application as a nonenzymatic electrochemical sensor to quantify glucose in human blood samples. Co-PM-NDGPC/SPE nanocomposite electrode fabrication was achieved using a single-step electrodeposition method under cyclic voltammetry (CV) technique under 1 M NH4Cl solution at 20 constitutive CV cycles (sweep rate 20 mV/s). Notably, the fabricated nonenzymatic electroactive nanocomposite material exhibited excellent electrocatalytic sensing towards the quantification of glucose in 0.1 M NaOH over a wide concentration range from 0.03 to 1.071 mM with a sensitive limit of detection 7.8 μM. Moreover, the Co-PM-NDGPC nanocomposite electrode with low charge transfer resistance (Rct∼81 Ω) and high ionic diffusion indicates excellent stability, reproducibility, and high sensitivity. The fabricated nanocomposite materials exhibit a commendable sensing response toward glucose molecules present in the blood serum samples recommends its usage in real-time applications.
    Matched MeSH terms: Cobalt
  3. Catalytic oxidative desulfurisation over Co/Fe-γAl2O3 catalyst: performance, characterisation and computational study
    Nazmi NASM, Razak FIA, Mokhtar WNAW, Ibrahim MNM, Adam F, Yahaya N, et al.
    Environ Sci Pollut Res Int, 2022 Jan;29(1):1009-1020.
    PMID: 34341936 DOI: 10.1007/s11356-021-15733-1
    The world faces the challenge to produce ultra-low sulfur diesel with low-cost technology. Therefore, this research emphasised on production of low sulfur fuel utilising nanoparticle catalyst under mild condition. A small amount of cobalt oxide (10-30 wt%) was introduced into the Fe/Al2O3 catalyst through the wet impregnation method. Cobalt modification induces a positive effect on the performance of the iron catalyst. Hence, the insertion of cobalt species into Fe/Al2O3 led to the formation of lattice fringes in all directions which resulted in the formation of Co3O4 and Fe3O4 species. The optimised catalyst, Co/Fe-Al2O3, calcined at 400 °C with a dopant ratio of 10:90 indicating the highest desulfurisation activity by removing 96% of thiophene, 100% of dibenzothiophene (DBT) and 92% of 4,6-dimethyl dibenzothiophene (4,6-DMDBT). Based on the density functional theory (DFT) on Co/Fe-Al2O3, two pathways with the overall energy of -40.78 eV were suggested for the complete oxidation of DBT.
    Matched MeSH terms: Cobalt
  4. Hierarchical ZIF-decorated nanoflower-covered 3-dimensional foam for enhanced catalytic reduction of nitrogen-containing contaminants
    Lin JY, Lee J, Oh WD, Kwon E, Tsai YC, Lisak G, et al.
    J Colloid Interface Sci, 2021 Nov 15;602:95-104.
    PMID: 34118608 DOI: 10.1016/j.jcis.2021.05.098
    Metal Organic Frameworks (MOFs) represent a promising class of metallic catalysts for reduction of nitrogen-containing contaminants (NCCs), such as 4-nitrophenol (4-NP). Nevertheless, most researches involving MOFs for 4-NP reduction employ noble metals in the form of fine powders, making these powdered noble metal-based MOFs impractical and inconvenient for realistic applications. Thus, it would be critical to develop non-noble-metal MOFs which can be incorporated into macroscale and porous supports for convenient applications. Herein, the present study proposes to develop a composite material which combines advantageous features of macroscale/porous supports, and nanoscale functionality of MOFs. In particular, copper foam (CF) is selected as a macroscale porous medium, which is covered by nanoflower-structured CoO to increase surfaces for growing a cobaltic MOF, ZIF-67. The resultant composite comprises of CF covered by CoO nanoflowers decorated with ZIF-67 to form a hierarchical 3D-structured catalyst, enabling this ZIF-67@Cu foam (ZIF@CF) a promising catalyst for reducing 4-NP, and other NCCs. Thus, ZIF@CF can readily reduce 4-NP to 4-AP with a significantly lower Ea of 20 kJ/mol than reported values. ZIF@CF could be reused over 10 cycles and remain highly effective for 4-NP reduction. ZIF@CF also efficiently reduces other NCCs, such as 2-nitrophenol, 3-nitrophenol, methylene blue, and methyl orange. ZIF@CF can be adopted as catalytic filters to enable filtration-type reduction of NCCs by passing NCC solutions through ZIF@CF to promptly and conveniently reduce NCCs. The versatile and advantageous catalytic activity of ZIF@CF validates that ZIF@CF is a promising and practical heterogeneous catalyst for reductive treatments of NCCs.
    Matched MeSH terms: Cobalt
  5. Borosilicate glass 60Co high dose rate brachytherapy thermoluminescence dosimetry
    Nazeri AAZA, Sani SFA, Ung NM, Almugren KS, Alkallas FH, Bradley DA
    Appl Radiat Isot, 2021 Oct;176:109814.
    PMID: 34175543 DOI: 10.1016/j.apradiso.2021.109814
    Brachytherapy is commonly used in treatment of cervical, prostate, breast and skin cancers, also for oral cancers, typically via the application of sealed radioactive sources that are inserted within or alongside the area to be treated. A particular aim of the various brachytherapy techniques is to accurately transfer to the targeted tumour the largest possible dose, at the same time minimizing dose to the surrounding normal tissue, including organs at risk. The dose fall-off with distance from the sources is steep, the dose gradient representing a prime factor in determining the dose distribution, also representing a challenge to the conduct of measurements around sources. Amorphous borosilicate glass (B2O3) in the form of microscope cover slips is recognized to offer a practicable system for such thermoluminescence dosimetry (TLD), providing for high-spatial resolution (down to 
    Matched MeSH terms: Cobalt Radioisotopes/administration & dosage*
  6. Correlation analysis of CT-based rectal planning dosimetric parameters with in vivo dosimetry of MOSkin and PTW 9112 detectors in Co-60 source HDR intracavitary cervix brachytherapy
    Jamalludin Z, Malik RA, Ung NM
    Phys Eng Sci Med, 2021 Sep;44(3):773-783.
    PMID: 34191272 DOI: 10.1007/s13246-021-01026-x
    Intracavitary cervical brachytherapy delivers high doses of radiation to the target tissue and a portion of these doses will also hit the rectal organs due to their close proximity. Rectal dose can be evaluated from dosimetric parameters in the treatment planning system (TPS) and in vivo (IV) dose measurement. This study analyzed the correlation between IV rectal dose with selected volume and point dose parameters from TPS. A total of 48 insertions were performed and IV dose was measured using the commercial PTW 9112 semiconductor diode probe. In 18 of 48 insertions, a single MOSkin detector was attached on the probe surface at 50 mm from the tip. Four rectal dosimetric parameters were retrospectively collected from TPS; (a) PTW 9112 diode maximum reported dose (RPmax) and MOSkin detector, (b) minimum dose to 2 cc (D2cc), (c) ICRU reference point (ICRUr), and (d) maximum dose from additional points (Rmax). The IV doses from both detectors were analyzed for correlation with these dosimetric parameters. This study found a significantly high correlation between IV measured dose from RPmax (r = 0.916) and MOSkin (r = 0.959) with TPS planned dose. The correlation between measured RPmax with both D2cc and Rmax revealed high correlation of r > 0.7, whereas moderate correlation (r = 0.525) was observed with ICRUr. There was no significant correlation between MOSkin IV measured dose with D2cc, ICRUr and Rmax. The non-significant correlation between parameters was ascribable to differences in both detector position within patients, and dosimetric volume and point location determined on TPS, rather than detector uncertainties.
    Matched MeSH terms: Cobalt Radioisotopes
  7. Synthesis, characterization and multiple targeting with selectivity: Anticancer property of ternary metal phenanthroline-maltol complexes
    Ng CH, Tan TH, Tioh NH, Seng HL, Ahmad M, Ng SW, et al.
    J Inorg Biochem, 2021 07;220:111453.
    PMID: 33895694 DOI: 10.1016/j.jinorgbio.2021.111453
    The cobalt(II), copper(II) and zinc(II) complexes of 1,10-phenanthroline (phen) and maltol (mal) (complexes 1, 2, 3 respectively) were prepared from their respective metal(II) chlorides and were characterized by FT-IR, elemental analysis, UV spectroscopy, molar conductivity, p-nitrosodimethylaniline assay and mass spectrometry. The X-ray structure of a single crystal of the zinc(II) analogue reveals a square pyramidal structure with distinctly shorter apical chloride bond. All complexes were evaluated for their anticancer property on breast cancer cell lines MCF-7 and MDA-MB-231, and normal cell line MCF-10A, using (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and morphological studies. Complex 2 was most potent for 24, 48 and 72 h treatment of cancer cells but it was not selective towards cancer over normal cells. The mechanistic studies of the cobalt(II) complex 1 involved apoptosis assay, cell cycle analysis, dichloro-dihydro-fluorescein diacetate assay, intracellular reactive oxygen species assay and proteasome inhibition assay. Complex 1 induced low apoptosis, generated low level of ROS and did not inhibit proteasome in normal cells. The study of the DNA binding and nucleolytic properties of complexes 1-3 in the absence or presence of H2O2 or sodium ascorbate revealed that only complex 1 was not nucleolytic.
    Matched MeSH terms: Cobalt/chemistry
  8. Metal-complexed covalent organic frameworks derived N-doped carbon nanobubble-embedded cobalt nanoparticle as a magnetic and efficient catalyst for oxone activation
    Nguyen HT, Lee J, Kwon E, Lisak G, Thanh BX, Oh WD, et al.
    J Colloid Interface Sci, 2021 Jun;591:161-172.
    PMID: 33601102 DOI: 10.1016/j.jcis.2021.01.108
    While Cobalt nanoparticles (Co NPs) are useful for catalytic Oxone activation, it is more advantageous to embed/immobilize Co NPs on nitrogen-doped carbon substrates to provide synergy for enhancing catalytic performance. Herein, this study proposes to fabricate such a composite by utilizing covalent organic frameworks (COF) as a precursor. Through complexation of COF with Co, a stable product of Co-complexed COF (Co-COF) can be synthesized. This Co-COF is further converted through pyrolysis to N-doped carbon in which cobaltic NPs are embedded. Owing to its well-defined structures of Co-COF, the pyrolysis process transforms COF into N-doped carbon with a bubble-like morphology. Such Co NP-embedded N-doped carbon nanobubbles (CoCNB) with pores, magnetism and Co, shall be a promising catalyst. Thus, CoCNB shows a much stronger catalytic activity than commercial Co3O4 NPs to activate Oxone to degrade toxic Amaranth dye (AMD). CoCNB-activated Oxone also achieves a significantly lower Ea value of AMD degradation (i.e., 27.9 kJ/mol) than reported Ea values in previous literatures. Besides, CoCNB is still effective for complete elimination of AMD in the presence of high-concentration NaCl and surfactants, and CoCNB is also reusable over five consecutive cycles.
    Matched MeSH terms: Cobalt
  9. Sulfur-doped graphitic carbon nitride incorporated bismuth oxychloride/Cobalt based type-II heterojunction as a highly stable material for photoelectrochemical water splitting
    Vinoth S, Ong WJ, Pandikumar A
    J Colloid Interface Sci, 2021 Jun;591:85-95.
    PMID: 33592528 DOI: 10.1016/j.jcis.2021.01.104
    Cobalt incorporated sulfur-doped graphitic carbon nitride with bismuth oxychloride (Co/S-gC3N4/BiOCl) heterojunction is prepared by an ultrasonically assisted hydrothermal treatment. The heterojunction materials have employed in photoelectrochemical (PEC) water splitting. The PEC activity and stability of the materials are promoted by constructing an interface between the visible light active semiconductor photocatalyst and cocatalysts. The photocurrent density of Co-9% S-gC3N4/BiOCl has attained 393.0 μA cm-2 at 1.23 V vs. RHE, which is 7-fold larger than BiOCl and ~3-fold higher than 9% S-gC3N4/BiOCl. The enhanced PEC activity can be attributed to the improved electron-hole charge separation and the boosted charge transfer is confirmed by photoluminescence (PL) and electrochemical impedance spectroscopy (EIS) analysis. The fabricated Co/S-gC3N4/BiOCl nanohybrid material has exhibited high stability of up to 10,800 s (3 h) at 1.23 V vs. RHE during PEC water splitting reaction and the obtained photo-conversion efficiency is 3.7-fold greater than S-gC3N4/BiOCl and 17-fold higher than BiOCl. The FESEM and HRTEM images have revealed the formation of heterojunction interface between S-gC3N4 and BiOCl and the elemental mapping has confirmed the presence of cobalt over S-gC3N4/BiOCl. The heterojunction interface has facilitated the photo-excited charge separation and transport across the electrode/electrolyte interface and also the flat-band potential, which is confirmed by Mott-Schottky analysis.
    Matched MeSH terms: Cobalt
  10. An investigation on the relationship between physicochemical characteristics of alumina-supported cobalt catalyst and its performance in dry reforming of methane
    Khairudin NF, Mohammadi M, Mohamed AR
    Environ Sci Pollut Res Int, 2021 Jun;28(23):29157-29176.
    PMID: 33550559 DOI: 10.1007/s11356-021-12794-0
    This study deals with the development of alumina-supported cobalt (Co/Al2O3) catalysts with remarkable performance in dry reforming of methane (DRM) and least carbon deposition. The influence of Co content, calcination, and reduction temperatures on the physicochemical attributes and catalyst activity of the developed catalysts was extensively studied. For this purpose, several characterization techniques including ICP-MS, H2 pulse chemisorption, HRTEM, H2-TPR, N2 adsorption desorption, and TGA were implemented, and the properties of the developed catalysts were carefully analyzed. The impact of reaction temperature, feed gas ratio, and gas hourly space velocity (GHSV) on the reactants conversion and products yield was investigated. Use of 10%Co/Al2O3 catalyst, calcined at 500°C and reduced under H2 at 900°C in DRM reaction at 850°C, CH4/CO2 ratio of 1:1, and GHSV of 6 L.g-1.h-1 resulted in a remarkable catalytic activity and sustainable performance in long-term operation where great CO2 (96%) and CH4 (98%) conversions and high H2 (83%) and CO (91%) yields with a negligible carbon deposition (3 wt%) were attained in 100-h on-stream reaction. The good performance of the developed catalyst in DRM reaction was attributed to the small Co particle size with well-dispersion on the alumina support which increased the catalytic activity and also the strong metal-support interaction which inhibited any serious metal sintering and enhanced the catalyst stability.
    Matched MeSH terms: Cobalt
  11. Fulltext Waste Fiber-Based Poly(hydroxamic acid) Ligand for Toxic Metals Removal from Industrial Wastewater
    Rahman ML, Wong ZJ, Sarjadi MS, Joseph CG, Arshad SE, Musta B, et al.
    Polymers (Basel), 2021 May 06;13(9).
    PMID: 34066308 DOI: 10.3390/polym13091486
    Toxic metals in the industrial wastewaters have been liable for drastic pollution hence a powerful and economical treatment technology is needed for water purification. For this reason, some pure cellulosic materials were derived from waste fiber to obtain an economical adsorbent for wastewater treatment. Conversion of cellulose into grafting materials such as poly(methyl acrylate)-grafted cellulose was performed by free radical grafting process. Consequently, poly(hydroxamic acid) ligand was produced from the grafted cellulose. The intermediate products and poly(hydroxamic acid) ligand were analyzed by FT-IR, FE-SEM, TEM, EDX, and XPS spectroscopy. The adsorption capacity (qe) of some toxic metals ions by the polymer ligand was found to be excellent, e.g., copper capacity (qe) was 346.7 mg·g-1 at pH 6. On the other hand, several metal ions such as cobalt chromium and nickel also demonstrated noteworthy sorption capacity at pH 6. The adsorption mechanism obeyed the pseudo second-order rate kinetic model due to the satisfactory correlated experimental sorption values (qe). Langmuir model isotherm study showed the significant correlation coefficient with all metal ions (R2 > 0.99), indicating that the single or monolayer adsorption was the dominant mode on the surface of the adsorbent. This polymer ligand showed good properties on reusability. The result shows that the adsorbent may be recycled for 6 cycles without any dropping of starting sorption capabilities. This polymeric ligand showed outstanding toxic metals removal magnitude, up to 90-99% of toxic metal ions can be removed from industrial wastewater.
    Matched MeSH terms: Cobalt
  12. Antimicrobial properties of multifunctional polypyrrole-cobalt oxide-silver nanocomposite against pathogenic bacteria and parasite
    Masri A, Abdelnasir S, Anwar A, Iqbal J, Numan A, Jagadish P, et al.
    Appl Microbiol Biotechnol, 2021 Apr;105(8):3315-3325.
    PMID: 33797573 DOI: 10.1007/s00253-021-11221-1
    BACKGROUND: Conducting polymer based nanocomposites are known to be effective against pathogens. Herein, we report the antimicrobial properties of multifunctional polypyrrole-cobalt oxide-silver nanocomposite (PPy-Co3O4-AgNPs) for the first time. Antibacterial activities were tested against multi-drug-resistant Gram-negative Escherichia coli (E. coli) and Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) bacteria, while antiamoebic effects were assessed against opportunistic protist Acanthamoeba castellanii (A. castellanii).

    RESULTS: The ternary nanocomposite containing conducting polymer polypyrrole, cobalt oxide, and silver nanoparticles showed potent antimicrobial effects against these pathogens. The antibacterial assay showed that PPy-Co3O4-AgNPs exhibited significant bactericidal activity against neuropathogenic E. coli K1 at only 8 μg/mL as compared to individual components of the nanocomposite, whereas a 70 % inhibition of A. castellanii viability was observed at 50 μg/mL. Moreover, PPy-Co3O4-AgNPs were found to have minimal cytotoxicity against human keratinocytes HaCaT cells in vitro even at higher concentration (50 μg/mL), and also reduced the microbes-mediated cytopathogenicity against host cells.

    CONCLUSION: These results demonstrate that PPy-Co3O4-AgNPs hold promise in the development of novel antimicrobial nanomaterials for biomedical applications.

    KEY POINTS: •Synthesis of polypyrrole-cobalt oxide-silver (PPy-Co3O4-AgNPs) nanocomposite. •Antimicrobial activity of nanocomposite. •PPy-Co3O4-AgNPs hold promise for biomedical applications.

    Matched MeSH terms: Cobalt
  13. Fulltext Optical Properties and Conductivity of PVA-H3PO4 (Polyvinyl Alcohol-Phosphoric Acid) Film Blend Irradiated by γ-Rays
    Susilawati S, Prayogi S, Arif MF, Ismail NM, Bilad MR, Asy'ari M
    Polymers (Basel), 2021 Mar 28;13(7).
    PMID: 33800592 DOI: 10.3390/polym13071065
    This study assesses the optical properties and conductivity of PVA-H3PO4 (polyvinyl alcohol-phosphoric acid) polymer film blend irradiated by gamma (γ) rays. The PVA-H3PO4 polymer film blend was prepared by the solvent-casting method at H3PO4 concentrations of 75 v% and 85 v%, and then irradiated up to 25 kGy using γ-rays from the Cobalt-60 isotope source. The optical absorption spectrum was measured using an ultraviolet-visible spectrophotometer over a wavelength range of 200 to 700 nm. It was found that the absorption peaks are in three regions, namely two peaks in the ultraviolet region (310 and 350 nm) and one peak in the visible region (550 nm). The presence of an absorption peak after being exposed to hυ energy indicates a transition of electrons from HOMO to LUMO within the polymer chain. The study of optical absorption shows that the energy band gap (energy gap) depends on the radiation dose and the concentration of H3PO4 in the polymer film blend. The optical absorption, absorption edge, and energy gap decrease with increasing H3PO4 concentration and radiation dose. The interaction between PVA and H3PO4 blend led to an increase in the conductivity of the resulting polymer blend film.
    Matched MeSH terms: Cobalt Radioisotopes
  14. Fulltext Tool Wear and Surface Evaluation in Drilling Fly Ash Geopolymer Using HSS, HSS-Co, and HSS-TiN Cutting Tools
    Ghazali MF, Abdullah MMAB, Abd Rahim SZ, Gondro J, Pietrusiewicz P, Garus S, et al.
    Materials (Basel), 2021 Mar 26;14(7).
    PMID: 33810517 DOI: 10.3390/ma14071628
    This paper reports on the potential use of geopolymer in the drilling process, with respect to tool wear and surface roughness. The objectives of this research are to analyze the tool life of three different economy-grade drill bit uncoated; high-speed steel (HSS), HSS coated with TiN (HSS-TiN), and HSS-cobalt (HSS-Co) in the drilling of geopolymer and to investigate the effect of spindle speed towards the tool life and surface roughness. It was found that, based on the range of parameters set in this experiment, the spindle speed is directly proportional to the tool wear and inversely proportional to surface roughness. It was also observed that HSS-Co produced the lowest value of surface roughness compared to HSS-TiN and uncoated HSS and therefore is the most favorable tool to be used for drilling the material. For HSS, HSS coated with TiN, and HSS-Co, only the drilling with the spindle speed of 100 rpm was able to drill 15 holes without surpassing the maximum tool wear of 0.10 mm. HSS-Co exhibits the greatest tool life by showing the lowest value of flank wear and produce a better surface finish to the sample by a low value of surface roughness value (Ra). This finding explains that geopolymer is possible to be drilled, and therefore, ranges of cutting tools and parameters suggested can be a guideline for researchers and manufacturers to drill geopolymer for further applications.
    Matched MeSH terms: Cobalt
  15. Fulltext Electrodeposited Hybrid Biocathode-Based CO2 Reduction via Microbial Electro-Catalysis to Biofuels
    Anwer AH, Khan N, Umar MF, Rafatullah M, Khan MZ
    Membranes (Basel), 2021 Mar 22;11(3).
    PMID: 33810075 DOI: 10.3390/membranes11030223
    Microbial electrosynthesis is a new approach to converting C1 carbon (CO2) to more complex carbon-based products. In the present study, CO2, a potential greenhouse gas, was used as a sole carbon source and reduced to value-added chemicals (acetate, ethanol) with the help of bioelectrochemical reduction in microbial electrosynthesis systems (MES). The performance of MES was studied with varying electrode materials (carbon felt, stainless steel, and cobalt electrodeposited carbon felt). The MES performance was assessed in terms of acetic acid and ethanol production with the help of gas chromatography (GC). The electrochemical characterization of the system was analyzed with chronoamperometry and cyclic voltammetry. The study revealed that the MES operated with hybrid cobalt electrodeposited carbon felt electrode yielded the highest acetic acid (4.4 g/L) concentration followed by carbon felt/stainless steel (3.7 g/L), plain carbon felt (2.2 g/L), and stainless steel (1.87 g/L). The alcohol concentration was also observed to be highest for the hybrid electrode (carbon felt/stainless steel/cobalt oxide is 0.352 g/L) as compared to the bare electrodes (carbon felt is 0.22 g/L) tested, which was found to be in correspondence with the pH changes in the system. Electrochemical analysis revealed improved electrotrophy in the hybrid electrode, as confirmed by the increased redox current for the hybrid electrode as compared to plain electrodes. Cyclic voltammetry analysis also confirmed the role of the biocatalyst developed on the electrode in CO2 sequestration.
    Matched MeSH terms: Cobalt
  16. CoS2 engulfed ultra-thin S-doped g-C3N4 and its enhanced electrochemical performance in hybrid asymmetric supercapacitor
    Vinoth S, Subramani K, Ong WJ, Sathish M, Pandikumar A
    J Colloid Interface Sci, 2021 Feb 15;584:204-215.
    PMID: 33069019 DOI: 10.1016/j.jcis.2020.09.071
    This work demonstrates a high-performance hybrid asymmetric supercapacitor (HASC) workable in very high current density of 30 A g-1 with in-situ pyrolytic processed sulfur-doped graphitic carbon nitride/cobalt disulfide (S-gC3N4/CoS2) materials and bio-derived carbon configuration and achievement of high electrochemical stability of 89% over 100,000 cycles with the coulombic efficiency of 99.6%. In the electrochemical studies, the S-gC3N4/CoS2-II electrode showed a high specific capacity of 180 C g-1 at 1 A g-1 current density in the half-cell configuration. The HASC cell was fabricated using S-gC3N4/CoS2-II material and orange peel derived activated carbon as a positive and negative electrode with a maximum operating cell potential of 1.6 V, respectively. The fabricated HASC delivered a high energy density of 26.7 Wh kg-1 and power density of 19.8 kW kg-1 in aqueous electrolyte. The prominent properties in specific capacity and cycling stability could be attributed to the CoS2 nanoparticles engulfed into the S-gC3N4 framework which provides short transport distance of the ions, strong interfacial interaction, and improving structural stability of the S-gC3N4/CoS2-II materials.
    Matched MeSH terms: Cobalt
  17. Co3O4 nanocube-decorated nitrogen-doped carbon foam as an enhanced 3-dimensional hierarchical catalyst for activating Oxone to degrade sulfosalicylic acid
    Lin XR, Kwon E, Hung C, Huang CW, Oh WD, Lin KA
    J Colloid Interface Sci, 2021 Feb 15;584:749-759.
    PMID: 33176929 DOI: 10.1016/j.jcis.2020.09.104
    As sulfosalicylic acid (SUA) is extensively used as a pharmaceutical product, discharge of SUA into the environment becomes an emerging environmental issue because of its low bio-degradability. Thus, SO4--based advanced oxidation processes have been proposed for degrading SUA because of many advantages of SO4-. As Oxone represents a dominant reagent for producing SO4-, and Co is the most capable metal for activating Oxone to generate SO4-, it is critical to develop an effective but easy-to-use Co-based catalysts for Oxone activation to degrade SUA. Herein, a 3D hierarchical catalyst is specially created by decorating Co3O4 nanocubes (NCs) on macroscale nitrogen-doped carbon form (NCF). This Co3O4-decorated NCF (CONCF) is free-standing, macroscale and even squeezable to exhibit interesting and versatile features. More importantly, CONCF consists of Co3O4 NCs evenly distributed on NCF without aggregation. The NCF not only serves as a support for Co3O4 NCs but also offers additional active sites to synergistically enhance catalytic activities towards Oxone activation. Therefore, CONCF exhibits a higher catalytic activity than the conventional Co3O4 nanoparticles for activating Oxone to fully eliminate SUA in 30 min with a rate constant of 0.142 min-1. CONCF exhibits a much lower Ea value of SUA degradation (35.2 kJ/mol) than reported values, and stable catalytic activities over multi-cyclic degradation of SUA. The mechanism of SUA degradation is also explored, and degradation intermediates of SUA degradation are identified to provide a possible pathway of SUA degradation. These features validate that CONCF is certainly a promising 3D hierarchical catalyst for enhanced Oxone activation to degrade SUA. The findings obtained here are also insightful to develop efficient heterogeneous Oxone-activating catalysts for eliminating emerging contaminants.
    Matched MeSH terms: Cobalt
  18. Fulltext Field demonstration of irradiated sodium alginate as tea production booster
    Hossain MA, Islam JMM, Hoque MM, Nahar S, Khan MA
    Heliyon, 2021 Jan;7(1):e05881.
    PMID: 33458447 DOI: 10.1016/j.heliyon.2020.e05881
    Sodium alginate oligomers were tested for tea plant growth promoter and anti-fungal agent in this experiment. Sodium alginate solutions were irradiated by Co-60 gamma radiation with different radiation doses to produce the oligomers. Irradiated solutions were then diluted into 150, 300 and 500 ppm prior to foliar application. Solutions were applied through foliar spraying at 7 days interval and the best response of tea plants in terms of various attributes were recorded. Tea buds were collected in 10 days of interval and the growth attributes like- total number of buds, fresh weight of buds, average leaf area and weight per bud, weight of made tea etc. were calculated. The experiment was continued up to 12 weeks and the attributes were averaged to get results per plucking. 12 kGy radiation doses along with 300ppm solution showed the best results and about 36% increase in productivity was found based on the fresh weight of buds. Total fungal count in tea leaves was also found to be reduced greatly. Based on the present study, irradiated sodium alginate could be used as safe and environmentally friendly agent to increase tea production.
    Matched MeSH terms: Cobalt Radioisotopes
  19. Fulltext Investigation of attributes of bourbon oil and cobalt nitrate constituted electrospun nanoscaffolds for blood compatibility and in vitro bone formation
    Jaganathan SK, Mani MP
    An Acad Bras Cienc, 2021;93(4):e20201140.
    PMID: 34705943 DOI: 10.1590/0001-3765202120201140
    This work aims to fabricate scaffold using polyurethane (PU) integrated with bourbon oil (BB) and cobalt nitrate (CoNO3) using the electrospinning technique. Morphological investigation signified a fall in fibre diameter for the PU/BB and PU/BB/CoNO3 nanocomposite than the PU. Spectral analysis indicated that BB and CoNO3 were added within the PU matrix. Wettability analysis insinuated an increase in the hydrophobic nature of the PU/BB than the PU. PU/BB/CoNO3 turned to be hydrophilic due to the integration of CoNO3 in the polymer matrix. Mechanical testing of PU/BB and PU/BB/CoNO3 indicated an increase in the tensile strength of the fabricated composites. Atomic force microscopy (AFM) portrayed the reduction in the roughness of the PU/BB and PU/BB/CoNO3 compared to the PU. The coagulation studies invariably documented the improved anticoagulant behaviour and less toxic nature of the PU/BB and PU/BB/CoNO3 in comparison with the PU. Further, bone mineralization testing revealed the enhanced apatite formation of the nanocomposite. Nanocomposite scaffolds with the fore-mentioned properties hold good potential for bone tissue engineering.
    Matched MeSH terms: Cobalt
  20. Fulltext Convergent patterns of tissue-level distribution of elements in different tropical woody nickel hyperaccumulator species from Borneo Island
    Abubakari F, Mesjasz-Przybyłowicz J, Przybyłowicz WJ, van der Ent A
    AoB Plants, 2020 Dec;12(6):plaa058.
    PMID: 33408845 DOI: 10.1093/aobpla/plaa058
    The Malaysian state of Sabah on the Island of Borneo has recently emerged as a global hotspot of nickel hyperaccumulator plants. This study focuses on the tissue-level distribution of nickel and other physiologically relevant elements in hyperaccumulator plants with distinct phylogenetical affinities. The roots, old stems, young stems and leaves of Flacourtia kinabaluensis (Salicaceae), Actephila alanbakeri (Phyllanthaceae), Psychotria sarmentosa (Rubiaceae) and young stems and leaves of Glochidion brunneum (Phyllanthaceae) were studied using nuclear microprobe (micro-PIXE and micro-BS) analysis. The tissue-level distribution of nickel found in these species has the same overall pattern as in most other hyperaccumulator plants studied previously, with substantial enrichment in the epidermal cells and in the phloem. This study also revealed enrichment of potassium in the spongy and palisade mesophyll of the studied species. Calcium, chlorine, manganese and cobalt were found to be enriched in the phloem and also concentrated in the epidermis and cortex of the studied species. Although hyperaccumulation ostensibly evolved numerous times independently, the basic mechanisms inferred from tissue elemental localization are convergent in these tropical woody species from Borneo Island.
    Matched MeSH terms: Cobalt
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