Displaying publications 101 - 120 of 146 in total

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  1. Decolorization and biotransformation pathway of textile dye by Cylindrocephalum aurelium
    Mostafa AA, Elshikh MS, Al-Askar AA, Hadibarata T, Yuniarto A, Syafiuddin A
    Bioprocess Biosyst Eng, 2019 Sep;42(9):1483-1494.
    PMID: 31076865 DOI: 10.1007/s00449-019-02144-3
    Due to environmental concern, the research to date has tended to focus on how textile dye removal can be carried out in a greener manner. Therefore, this study aims to evaluate the decolorization and biotransformation pathway of Mordant Orange-1 (MO-1) by Cylindrocephalum aurelium RY06 (C. aurelium RY06). Decolorization study was conducted in a batch experiment including the investigation of the effects of physio-chemical parameters. Enzymatic activity of C. aurelium RY06 during the decolorization was also investigated. Moreover, transformation and biodegradation of MO-1 by C. aurelium RY06 were observed using the gas chromatography-mass spectrometry. Manganese peroxidase, lignin peroxidase, laccase, 1,2-dioxygenase, and 2,3-dioxygenase enzymes were detected during the decolorization. In general, the present work concluded that the MO-1 was successfully degraded by C. aurelium RY06 and transformed to be maleic acid and to be isophtalic acid.
    Matched MeSH terms: Azo Compounds/metabolism*
  2. Degradation of methyl orange and congo red by using chitosan/polyvinyl alcohol/TiO2 electrospun nanofibrous membrane
    Habiba U, Lee JJL, Joo TC, Ang BC, Afifi AM
    Int J Biol Macromol, 2019 Jun 15;131:821-827.
    PMID: 30904531 DOI: 10.1016/j.ijbiomac.2019.03.132
    In this study, chitosan/polyvinyl alcohol/TiO2 nanofiber was fabricated via electrospinning at a pump rate of 1.5 mL/h and voltage 6 kV. Field-emission scanning electron microscopic images showed bead free finer nanofiber. Fourier transform infrared spectra proved the formation of strong bond among chitosan, polyvinyl alcohol and TiO2. X-ray powder diffraction showed that TiO2 became amorphous in the composite nanofiber. Toughness and thermal stability of the chitosan/PVA nanofibrous membrane was increased with addition TiO2. The chitosan/PVA/TiO2 nanofibrous membrane was stable at basic medium. But degraded in acidic and water medium after 93 and 162 h, respectively. The adsorption mechanism of congo red obeyed the Langmuir isotherm model. On the other hand, adsorption characteristic of methyl orange fitted well with both Langmuir and Freundlich isotherm models. The maximum adsorption capacity of the resulting membrane for congo red and methyl orange is 131 and 314 mg/g, respectively. However, a high dose of adsorbent was required for congo red.
    Matched MeSH terms: Azo Compounds/chemistry*
  3. Fulltext Decolourisation Capabilities of Ligninolytic Enzymes Produced by Marasmius cladophyllus UMAS MS8 on Remazol Brilliant Blue R and Other Azo Dyes
    Sing NN, Husaini A, Zulkharnain A, Roslan HA
    Biomed Res Int, 2017;2017:1325754.
    PMID: 28168194 DOI: 10.1155/2017/1325754
    Marasmius cladophyllus was examined for its ability to degradatively decolourise the recalcitrant dye Remazol Brilliant Blue R (RBBR) and screened for the production of ligninolytic enzymes using specific substrates. Monitoring dye decolourisation by the decrease in absorbance ratio of A592/A500 shows that the decolourisation of RBBR dye was associated with the dye degradation. Marasmius cladophyllus produces laccase and lignin peroxidase in glucose minimal liquid medium containing RBBR. Both enzyme activities were increased, with laccase activity recorded 70 times higher reaching up to 390 U L-1 on day 12. Further in vitro RBBR dye decolourisation using the culture medium shows that laccase activity was correlated with the dye decolourisation. Fresh RBBR dye continuously supplemented into the decolourised culture medium was further decolourised much faster in the subsequent round of the RBBR dye decolourisation. In vitro dye decolourisation using the crude laccase not only decolourised 76% of RBBR dye in just 19 hours but also decolourised 54% of Orange G and 33% of Congo red at the same period of time without the use of any exogenous mediator. This rapid dye decolourisation ability of the enzymes produced by M. cladophyllus thus suggested its possible application in the bioremediation of dye containing wastewater.
    Matched MeSH terms: Azo Compounds/metabolism*
  4. Degradation reaction of Diazo reactive black 5 dye with copper (II) sulfate catalyst in thermolysis treatment
    Lau YY, Wong YS, Ang TZ, Ong SA, Lutpi NA, Ho LN
    Environ Sci Pollut Res Int, 2018 Mar;25(7):7067-7075.
    PMID: 29275478 DOI: 10.1007/s11356-017-1069-9
    The theme of present research demonstrates performance of copper (II) sulfate (CuSO4) as catalyst in thermolysis process to treat reactive black 5 (RB 5) dye. During thermolysis without presence of catalyst, heat was converted to thermal energy to break the enthalpy of chemical structure bonding and only 31.62% of color removal. With CuSO4 support as auxiliary agent, the thermally cleaved molecular structure was further destabilized and reacted with CuSO4. Copper ions functioned to delocalize the coordination of π of the lone paired electron in azo bond, C=C bond of the sp2 carbon to form C-C of the sp3 amorphous carbon in benzene and naphthalene. Further, the radicals of unpaired electrons were stabilized and RB 5 was thermally decomposed to methyl group. Zeta potential measurement was carried out to analyze the mechanism of RB 5 degradation and measurement at 0 mV verified the critical chemical concentration (CCC) (0.7 g/L copper (II) sulfate), as the maximum 92.30% color removal. The presence of copper (II) sulfate catalyst has remarkably increase the RB 5 dye degradation as the degradation rate constant without catalyst, k1 is 6.5224 whereas the degradation rate constant with catalyst, k2 is 25.6810. This revealed the correlation of conversion of thermal energy from heat to break the chemical bond strength, subsequent fragmentation of RB 5 dye molecular mediated by copper (II) sulfate catalyst. The novel framework on thermolysis degradation of molecular structure of RB 5 with respect to the bond enthalpy and interfacial intermediates decomposition with catalyst reaction were determined.
    Matched MeSH terms: Azo Compounds/analysis*
  5. Solar photocatalytic degradation of mono azo methyl orange and diazo reactive green 19 in single and binary dye solutions: adsorbability vs photodegradation rate
    Ong SA, Min OM, Ho LN, Wong YS
    Environ Sci Pollut Res Int, 2013 May;20(5):3405-13.
    PMID: 23114839 DOI: 10.1007/s11356-012-1286-1
    The objective of this study was to examine the effects of adsorbability and number of sulfonate group on solar photocatalytic degradation of mono azo methyl orange (MO) and diazo Reactive Green 19 (RG19) in single and binary dye solutions. The adsorption capacity of MO and RG19 onto the TiO₂ was 16.9 and 26.8 mg/g, respectively, in single dye solution, and reduced to 5.0 and 23.1 mg/g, respectively, in the binary dye solution. The data obtained for photocatalytic degradation of MO and RG19 in single and binary dye solution were well fitted with the Langmuir-Hinshelwood kinetic model. The pseudo-first-order rate constants of diazo RG19 were significant higher than the mono azo MO either in single or binary dye solutions. The higher number of sulfonate group in RG19 contributed to better adsorption capacity onto the surface of TiO₂ than MO indicating greater photocatalytic degradation rate.
    Matched MeSH terms: Azo Compounds/chemistry*
  6. Fulltext Thermodynamic and spectroscopic investigation of interactions between reactive red 223 and reactive orange 122 anionic dyes and cetyltrimethyl ammonium bromide (CTAB) cationic surfactant in aqueous solution
    Irfan M, Usman M, Mansha A, Rasool N, Ibrahim M, Rana UA, et al.
    ScientificWorldJournal, 2014;2014:540975.
    PMID: 25243216 DOI: 10.1155/2014/540975
    The present study describes the conductometric and spectroscopic study of the interaction of reactive anionic dyes, namely, reactive red 223 and reactive orange 122 with the cationic surfactant cetyltrimethyl ammonium bromide (CTAB). In a systematic investigation, the electrical conductivity data was used to calculate various thermodynamic parameters such as free energy (ΔG), enthalpy (ΔH), and the entropy (ΔS) of solubilization. The trend of change in these thermodynamic quantities indicates toward the entropy driven solubilization process. Moreover, the results from spectroscopic data reveal high degree of solubilization, with strong interactions observed in the cases of both dyes and the CTAB. The spontaneous nature of solubilization and binding was evident from the observed negative values of free energies (ΔG p and ΔG b).
    Matched MeSH terms: Azo Compounds/analysis*; Azo Compounds/metabolism
  7. Decolourisation of Acid Orange 7 recalcitrant auto-oxidation coloured by-products using an acclimatised mixed bacterial culture
    Bay HH, Lim CK, Kee TC, Ware I, Chan GF, Shahir S, et al.
    Environ Sci Pollut Res Int, 2014 Mar;21(5):3891-906.
    PMID: 24293297 DOI: 10.1007/s11356-013-2331-4
    This study focuses on the biodegradation of recalcitrant, coloured compounds resulting from auto-oxidation of Acid Orange 7 (AO7) in a sequential facultative anaerobic-aerobic treatment system. A novel mixed bacterial culture, BAC-ZS, consisting of Brevibacillus panacihumi strain ZB1, Lysinibacillus fusiformis strain ZB2, and Enterococcus faecalis strain ZL bacteria were isolated from environmental samples. The acclimatisation of the mixed culture was carried out in an AO7 decolourised solution. The acclimatised mixed culture showed 98 % decolourisation within 2 h of facultative anaerobic treatment using yeast extract and glucose as co-substrate. Subsequent aerobic post treatment caused auto-oxidation reaction forming dark coloured compounds that reduced the percentage decolourisation to 73 %. Interestingly, further agitations of the mixed culture in the solution over a period of 48 h significantly decolourise the coloured compounds and increased the decolourisation percentage to 90 %. Analyses of the degradation compounds using UV-visible spectrophotometer, Fourier transform infrared spectroscopy (FTIR) and high performance liquid chromatography (HPLC) showed complete degradation of recalcitrant AO7 by the novel BAC-ZS. Phytotoxicity tests using Cucumis sativus confirmed the dye solution after post aerobic treatment were less toxic compared to the parent dye. The quantitative real-time PCR revealed that E. faecalis strain ZL was the dominant strain in the acclimatised mix culture.
    Matched MeSH terms: Azo Compounds/metabolism*; Azo Compounds/toxicity
  8. Biosorption and biodegradation of Acid Orange 7 by Enterococcus faecalis strain ZL: optimization by response surface methodological approach
    Lim CK, Bay HH, Aris A, Abdul Majid Z, Ibrahim Z
    Environ Sci Pollut Res Int, 2013 Jul;20(7):5056-66.
    PMID: 23334551 DOI: 10.1007/s11356-013-1476-5
    Reactive dyes account for one of the major sources of dye wastes in textile effluent. In this study, decolorization of the monoazo dye, Acid Orange 7 (AO7) by the Enterococcus faecalis strain ZL that isolated from a palm oil mill effluent treatment plant has been investigated. Decolorization efficiency of azo dye is greatly affected by the types of nutrients and the size of inoculum used. In this work, one-factor-at-a-time (method and response surface methodology (RSM) was applied to optimize these operational factors and also to study the combined interaction between them. Analysis of AO7 decolorization was done using Fourier transform infrared (FTIR) spectroscopy, desorption study, UV-Vis spectral analysis, field emission scanning electron microscopy (FESEM), and high performance liquid chromatography (HPLC). The optimum condition via RSM for the color removal of AO7 was found to be as follows: yeast extract, 0.1% w/v, glycerol concentration of 0.1% v/v, and inoculum density of 2.5% v/v at initial dye concentration of 100 mg/L at 37 °C. Decolorization efficiency of 98% was achieved in only 5 h. The kinetic of AO7 decolorization was found to be first order with respect to dye concentration with a k value of 0.87/h. FTIR, desorption study, UV-Vis spectral analysis, FESEM, and HPLC findings indicated that the decolorization of AO7 was mainly due to the biosorption as well as biodegradation of the bacterial cells. In addition, HPLC analyses also showed the formation of sulfanilic acid as a possible degradation product of AO7 under facultative anaerobic condition. This study explored the ability of E. faecalis strain ZL in decolorizing AO7 by biosorption as well as biodegradation process.
    Matched MeSH terms: Azo Compounds/analysis; Azo Compounds/metabolism*
  9. Fulltext Extraction, Analytical and Advanced Methods for Detection of Allura Red AC (E129) in Food and Beverages Products
    Rovina K, Siddiquee S, Shaarani SM
    Front Microbiol, 2016;7:798.
    PMID: 27303385 DOI: 10.3389/fmicb.2016.00798
    Allura Red AC (E129) is an azo dye that widely used in drinks, juices, bakery, meat, and sweets products. High consumption of Allura Red has claimed an adverse effects of human health including allergies, food intolerance, cancer, multiple sclerosis, attention deficit hyperactivity disorder, brain damage, nausea, cardiac disease and asthma due to the reaction of aromatic azo compounds (R = R' = aromatic). Several countries have banned and strictly controlled the uses of Allura Red in food and beverage products. This review paper is critically summarized on the available analytical and advanced methods for determination of Allura Red and also concisely discussed on the acceptable daily intake, toxicology and extraction methods.
    Matched MeSH terms: Azo Compounds
  10. A highly efficient single chambered up-flow membrane-less microbial fuel cell for treatment of azo dye Acid Orange 7-containing wastewater
    Thung WE, Ong SA, Ho LN, Wong YS, Ridwan F, Oon YL, et al.
    Bioresour Technol, 2015 Dec;197:284-8.
    PMID: 26342340 DOI: 10.1016/j.biortech.2015.08.078
    Single chambered up-flow membrane-less microbial fuel cell (UFML MFC) was developed to study the feasibility of the bioreactor for decolorization of Acid Orange 7 (AO7) and electricity generation simultaneously. The performance of UFML MFC was evaluated in terms of voltage output, chemical oxygen demand (COD) and color removal efficiency by varying the concentration of AO7 in synthetic wastewater. The results shown the voltage generation and COD removal efficiency decreased as the initial AO7 concentration increased; this indicates there is electron competition between anode and azo dye. Furthermore, there was a phenomenon of further decolorization at cathode region which indicates the oxygen and azo dye are both compete as electron acceptor. Based on the UV-visible spectra analysis, the breakdown of the azo bond and naphthalene compound in AO7 were confirmed. These findings show the capability of integrated UFML MFC in azo dye wastewater treatment and simultaneous electricity generation.
    Matched MeSH terms: Azo Compounds
  11. Improvement of the butanol production selectivity and butanol to acetone ratio (B:A) by addition of electron carriers in the batch culture of a new local isolate of Clostridium acetobutylicum YM1
    Nasser Al-Shorgani NK, Kalil MS, Wan Yusoff WM, Shukor H, Hamid AA
    Anaerobe, 2015 Dec;36:65-72.
    PMID: 26439644 DOI: 10.1016/j.anaerobe.2015.09.008
    Improvement in the butanol production selectivity or enhanced butanol:acetone ratio (B:A) is desirable in acetone-butanol-ethanol (ABE) fermentation by Clostridium strains. In this study, artificial electron carriers were added to the fermentation medium of a new isolate of Clostridium acetobutylicum YM1 in order to improve the butanol yield and B:A ratio. The results revealed that medium supplementation with electron carriers changed the metabolism flux of electron and carbon in ABE fermentation by YM1. A decrease in acetone production, which subsequently improved the B:A ratio, was observed. Further improvement in the butanol production and B:A ratios were obtained when the fermentation medium was supplemented with butyric acid. The maximum butanol production (18.20 ± 1.38 g/L) was gained when a combination of methyl red and butyric acid was added. Although the addition of benzyl viologen (0.1 mM) and butyric acid resulted in high a B:A ratio of 16:1 (800% increment compared with the conventional 2:1 ratio), the addition of benzyl viologen to the culture after 4 h resulted in the production of 18.05 g/L butanol. Manipulating the metabolic flux to butanol through the addition of electron carriers could become an alternative strategy to achieve higher butanol productivity and improve the B:A ratio.
    Matched MeSH terms: Azo Compounds
  12. Fulltext Hydrothermal preparation of silver telluride nanostructures and photo-catalytic investigation in degradation of toxic dyes
    Gholamrezaei S, Salavati-Niasari M, Ghanbari D, Bagheri S
    Sci Rep, 2016;6:20060.
    PMID: 26805744 DOI: 10.1038/srep20060
    Different morphologies of Ag2Te nanostructures were synthesized using TeCl4 as a new precursor and hydrazine hydrate as reducing agent by a hydrothermal method. Various parameters that affect on morphology and purity of nanostructures were optimized. According to our experiments the best time and temperature for preparation of this nanostructure are 12 h and 120 °C. The photo-catalytic behaviour of nanostructures in presence of UV-visible light for degradation of methyl orange was investigated. Results show that the presence of UV light is necessary for an efficient degradation of dye in aqueous solution. On the other hand, as observations propose the Ag2Te reveal a strong photoluminescence peak at room temperature that could be attributed to high level transition in the semiconductor. Nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) techniques and UV-visible scanning spectrometer (UV-Vis).
    Matched MeSH terms: Azo Compounds
  13. Design, Synthesis, SAR Study, Antimicrobial and Anticancer Evaluation of Novel 2-Mercaptobenzimidazole Azomethine Derivatives
    Tahlan S, Narasimhan B, Lim SM, Ramasamy K, Mani V, Shah SAA
    Mini Rev Med Chem, 2020;20(15):1559-1571.
    PMID: 30179132 DOI: 10.2174/1389557518666180903151849
    BACKGROUND: Various analogues of benzimidazole are found to be biologically and therapeutically potent against several ailments. Benzimidazole when attached with heterocyclic rings has shown wide range of potential activities. So, from the above provided facts, we altered benzimidazole derivatives so that more potent antagonists could be developed. In the search for a new category of antimicrobial and anticancer agents, novel azomethine of 2-mercaptobenzimidazole derived from 3-(2- (1H-benzo[d]imidazol-2-ylthio)acetamido)benzohydrazide were synthesized.

    RESULTS AND DISCUSSION: The synthesized analogues were characterized by FT-IR, 1H/13C-NMR and MS studies as well C, H, N analysis. All synthesized compounds were evaluated for in vitro antibacterial activity against Gram-positive (B. subtilis), Gram-negative (E. coli, P. aeruginosa, K. pneumoniae and S. typhi) strains and in vitro antifungal activity against C. albicans and A. niger strains by serial dilution method, the minimum inhibitory concentration (MIC) described in μM/ml. The in vitro anticancer activity of synthesized compounds was determined against human colorectal carcinoma cell line (HCT- 116) using 5-fluorouracil as standard drug.

    CONCLUSION: In general, most of the synthesized derivatives exhibited significant antimicrobial and anticancer activities. Compounds 8, 10, 15, 16, 17, 20 and 22 showed significant antimicrobial activity towards tested bacterial and fungal strains and compound 26 exhibited significant anticancer activity.

    Matched MeSH terms: Azo Compounds/chemical synthesis; Azo Compounds/pharmacology; Azo Compounds/chemistry*
  14. Physicochemical Properties of a Highly Efficient Cu-Ion-Doped TiO₂ Nanotube Photocatalyst for the Degradation of Methyl Orange Under Sunlight
    Razali MH, Noor AFM, Yusoff M
    J Nanosci Nanotechnol, 2020 02 01;20(2):965-972.
    PMID: 31383093 DOI: 10.1166/jnn.2020.16944
    In this study, a series of copper-ion-doped titanium dioxide (Cu-ion-doped TiO₂) nanotubes (NTs) were synthesized via a hydrothermal method by the concentration variation of doped Cu ions (0.00, 0.50, 1.00, 2.50, and 5.00 mmol). In addition, the samples were characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), nitrogen gas adsorption measurements, and ultraviolet-visible (UV-Vis) diffuse-reflectance spectroscopy. The photocatalytic activity of the Cu-iondoped TiO₂ NTs was investigated for the degradation of methyl orange (MO) under sunlight. The results obtained from the structural and morphological studies revealed that, at low concentrations of Cu-doped TiO₂ NTs, Cu is incorporated into the interstitial positions of the TiO₂ lattice, affording a new phase of TiO₂ (hexagonal) instead of the anatase TiO₂ (tetragonal) observed for undoped TiO₂ NTs. EDX analysis confirmed the presence of Cu in the TiO₂-based photocatalyst. All of the investigated samples exhibited a hollow fibrous-like structure, indicative of an NT morphology. The inner and outer diameters of the NTs were 4 nm and 10 nm, respectively. The photocatalysts exhibited a large surface area due to the NT morphology and a type IV isotherm and H3 hysteresis, corresponding to the mesopores and slit-shaped pores. The Cu-ion-doped TiO₂ NTs were excited by sunlight because of their low bandgap energy; and after the incorporation of Cu ions into the interstitial positions of the TiO₂ lattice, the NTs exhibited high visible-light activity owing to the low bandgap.
    Matched MeSH terms: Azo Compounds
  15. Decolorization and mineralization of Amaranth dye using multiple zoned aerobic and anaerobic baffled constructed wetland
    Lehl HK, Ong SA, Ho LN, Wong YS, Saad FNM, Oon YL, et al.
    Int J Phytoremediation, 2017 Aug 03;19(8):725-731.
    PMID: 28448169 DOI: 10.1080/15226514.2017.1284748
    The objective of this study is to determine the reduction efficiency of Chemical Oxygen Demand (COD) as well as the removal of color and Amaranth dye metabolites by the Aerobic-anaerobic Baffled Constructed Wetland Reactor (ABCW). The ABCW reactor was planted with common reed (Phragmite australis) where the hydraulic retention time (HRT) was set to 1 day and was fed with synthetic wastewater with the addition of Amaranth dye. Supplementary aeration was supplied in designated compartments of the ABCW reactor to control the aerobic and anaerobic zones. After Amaranth dye addition the COD reduction efficiency dropped from 98 to 91% while the color removal efficiency was 100%. Degradation of azo bond in Amaranth dye is shown by the UV-Vis spectrum analysis which demonstrates partial degradation of Amaranth dye metabolites. The performance of the baffled unit is due to the longer pathway as there is the up-flow and down-flow condition sequentially, thus allowing more contact of the wastewater with the rhizomes and micro-aerobic zones.
    Matched MeSH terms: Azo Compounds
  16. Fulltext Adsorption of acid dyes onto Zinc Chloride-Modified Cocoa (Theobroma Cacao) pod Husk-based carbon
    Nur Aqilah Zainal, Shariff Ibrahim, Borhannuddin Arifin
    Pertanika Journal of Science & Technology, 2017;25(103):129-138.
    MyJurnal
    An agricultural waste, the cocoa pod husk was chemically modified using a dehydrating agent, zinc chloride (ZnCl2), carbonised and used for the remediation of acid dyes in an aqueous solution. The targeted acid dyes are: (i) Acid Violet 17 (AV17); (ii) Acid Yellow 36 (AY36); and (iii) Acid Blue 29 (AB29). The physicochemical properties of the zinc chloride-modified cocoa pod husk-based carbon (ZCPHC) were characterised by ash content, bulk density, pH slurry, pHpzc and Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-Ray (EDX) analysis. The bulk density and ash content of the prepared carbon is 0.55 g cm-1 and 7.0% respectively. The photograph of SEM shows distinct changes at the ZCPHC carbon surface as it has large pores formed due to ZnCl2 modification. The adsorption tests were performed in a batch adsorption system using an aqueous solution of the understudy acid dyes. The influence of pH and dose of an adsorbent on the acid dye uptake was investigated and discussed. The adsorption was in favour at acidic condition with maximum removal observed at pH 2. The removal efficiency of the aqueous acid dye solution increased with the increase in adsorbent dosage. The kinetic experiment showed equilibrium time is less than 40 minutes and the kinetic data for all three understudy acid dyes fitted well with the pseudo-second-order model with a correlation coefficient (R2) values above 0.98.
    Matched MeSH terms: Azo Compounds
  17. Effect of degree of deacetylation of chitosan on adsorption capacity and reusability of chitosan/polyvinyl alcohol/TiO2 nano composite
    Habiba U, Joo TC, Siddique TA, Salleh A, Ang BC, Afifi AM
    Int J Biol Macromol, 2017 Nov;104(Pt A):1133-1142.
    PMID: 28690164 DOI: 10.1016/j.ijbiomac.2017.07.007
    The chitosan/polyvinyl alcohol/TiO2 composite was synthesized. Two different degrees of deacetylation of chitosan were prepared by hydrolysis to compare the effectiveness of them. The composite was analyzed via field emission scanning electron microscopy, Fourier transform infrared, X-ray diffraction, thermal gravimetric analysis, weight loss test and adsorption study. The FTIR and XRD results proved the interaction among chitosan, PVA and TiO2 without any chemical reaction. It was found that, chitosan with higher degree of deacetylation has better stability. Furthermore, it also showed that higher DD of chitosan required less time to reach equilibrium for methyl orange. The adsorption followed the pseudo-second-order kinetic model. The Langmuir and Freundlich isotherm models were fitted well for isotherm study. Adsorption capacity was higher for the composite containing chitosan with higher DD. The dye removal rate was independent of the dye's initial concentration. The adsorption capacity was increased with temperature and it was found from reusability test that the composite containing chitosan with higher DD is more reusable. It was notable that adsorption capacity was even after 15 runs. Therefore, chitosan/PVA/TiO2 composite can be a very useful material for dye removal.
    Matched MeSH terms: Azo Compounds
  18. Fulltext Free standing zirconia nanotubes formation and their photocatalytic properties
    Syahriza Ismail, Nurul Izza Soaid, Suriyati Mohamed Ansari, Nurulhuda Bashirom, Monna Rozana, Tan, Wai Kian, et al.
    Malaysian Journal of Microscopy, 2016;12(1):20-23.
    MyJurnal
    In the formation of ZrO2 (zirconia) nanotubes (ZNTs) by anodisation of zirconium, a balance between chemical etching at the surface of the nanotubes and inward growth inside the nanotubes is required. This can be achieved by using fluorinated organic electrolyte like ethylene glycol with the addition of small volume of oxidant. In this work, carbonate was selected as the oxidant and NH4F as the source of fluoride for chemical etching process. Two sets of electrolytes were studied EG/fluoride/Na2CO3 and EG/fluoride/K2CO3. It appears that in the presence of carbonate evolution of gas at the anode during the anodisation process was rather severe. The gas which is likely to be CO2 was found to weaken the adherence between the oxide film with the underlying Zr foil. This induced the formation of free standing ZNTs. High Resolution Transmission Electron Microscope (HRTEM) was used to investigate the crystallinity of the nanotubes where the majority crystal phase of ZNTs was tetragonal/cubic. The ZNTs were used as photocatalysts to oxidize methyl orange dye.
    Matched MeSH terms: Azo Compounds
  19. Fulltext Isolation and characterization of a molybdenum-reducing and Orange G-decolorizing Enterobacter sp. strain Zeid-6 in soils from Sudan
    Othman, A.R., Rahman, M.F., Shukor, M.Y., Abu Zeid, I.M., Ariffin, F.
    Bioremediation Science and Technology Research, 2015;3(2):13-19.
    MyJurnal
    Chemical toxins and organic contaminants such as hydrocarbons and dyes are major global
    contaminants with countless tones of those chemicals are created yearly with a significant
    amount release to the environment. In this work we screen the ability of a molybdenum-reducing
    bacterium isolated from contaminated soil to decolorize various azo and triphenyl methane dyes
    independent of molybdenum reduction. Biochemical analysis resulted in a tentative identification
    of the bacterium as Enterobacter sp. strain Zeid-6. The bacterium was able to decolorize the azo
    dye Orange G. The bacterium reduces molybdate to Mo-blue optimally at pH between 5.5 and
    8.0 and temperatures of between 30 and 37 oC. Other requirements include a phosphate
    concentration of 5 mM and a molybdate concentration of 20 mM. The absorption spectrum of the
    Mo-blue produced was similar to previous Mo-reducing bacterium, and closely resembles a
    reduced phosphomolybdate. Molybdenum reduction was inhibited by copper, lead, mercury and
    silver which showed 36.8, 16.9, 64.9 and 67.6% inhibition to Mo-reducing activity of
    Enterobacter sp. strain Zeid-6, respectively. The resultant molybdenum blue spectrum closely
    resembles the spectrum of molybdenum blue from the phosphate determination method. The
    ability of this bacterium to detoxify molybdenum and decolorize azo dye makes this bacterium
    an important tool for bioremediation.
    Matched MeSH terms: Azo Compounds
  20. Fulltext Removal of methyl orange dye by manganese/aluminium-layered double hydroxide
    Mamat, M., Abdullah, M.A.A., Jaafar, A.M., Soh, S.K.C., Lee, C.E.
    ASM Science Journal, 2018;11(101):105-113.
    MyJurnal
    As textile production flourishes nowadays, the amount of dyed wastewater entering the
    water body has also increased. Dyes could have serious negative impacts to the environment
    and also the human health, hence, they need to be removed from the water body. In this
    study, layered double hydroxide (LDH) of manganese/aluminium (MnAl) was synthesised
    to be used as a potential adsorbent to remove methyl orange (MO) dye due to its unique
    lamellar structure which provides LDH with high anion adsorption and exchange ability.
    MnAl was synthesized by using co-precipitation method and characterized by powder X-ray
    diffraction (PXRD), Fourier-Transform Infrared Spectroscopy (FTIR), Inductively coupled
    plasma atomic emission spectroscopy (ICP-AES) and Carbon, Hydrogen, Nitrogen, Sulphur
    (CHNS) elemental analysers, and Accelerated Surface Area and Porosity Analyzer (ASAP).
    Adsorption studies were conducted at different contact times and dosages of MnAl to evaluate
    the performance of MnAl in removing MO from water. Kinetic and isotherm models were
    tested using pseudo-first order, pseudo-second order, Langmuir isotherm and Freundlich
    isotherm. MnAl LDH was found to be perfectly fitted into pseudo-second order and Langmuir
    isotherm.
    Matched MeSH terms: Azo Compounds
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