Displaying publications 61 - 80 of 104 in total

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  1. Adeyi AA, Jamil SNAM, Abdullah LC, Choong TSY, Lau KL, Alias NH
    Molecules, 2020 Jun 07;25(11).
    PMID: 32517324 DOI: 10.3390/molecules25112650
    Proper remediation of aquatic environments contaminated by toxic organic dyes has become a research focus globally for environmental and chemical engineers. This study evaluates the adsorption potential of a polymer-based adsorbent, thiourea-modified poly(acrylonitrile-co-acrylic acid) (T-PAA) adsorbent, for the simultaneous uptake of malachite green (MG) and methylene blue (MB) dye ions from binary system in a continuous flow adsorption column. The influence of inlet dye concentrations, pH, flow rate, and adsorbent bed depth on adsorption process were investigated, and the breakthrough curves obtained experimentally. Results revealed that the sorption capacity of the T-PAA for MG and MB increase at high pH, concentration and bed-depth. Thomas, Bohart-Adams, and Yoon-Nelson models constants were calculated to describe MG and MB adsorption. It was found that the three dynamic models perfectly simulate the adsorption rate and behavior of cationic dyes entrapment. Finally, T-PAA adsorbent demonstrated good cyclic stability. It can be regenerated seven times (or cycles) with no significant loss in adsorption potential. Overall, the excellent sorption capacity and multiple usage make T-PAA polymer an attractive adsorbent materials for treatment of multicomponent dye bearing effluent in a fixed-bed column system.
    Matched MeSH terms: Coloring Agents/chemistry
  2. Chan GF, Gan HM, Rashid NA
    J Bacteriol, 2012 Oct;194(19):5485-6.
    PMID: 22965102 DOI: 10.1128/JB.01285-12
    Citrobacter sp. strain A1, isolated from a sewage oxidation pond, is a facultative aerobe and mesophilic dye-degrading bacterium. This organism degrades azo dyes efficiently via azo reduction and desulfonation, followed by the successive biotransformation of dye intermediates under an aerobic environment. Here we report the draft genome sequence of Citrobacter sp. A1.
    Matched MeSH terms: Coloring Agents/chemistry
  3. Goudarzi M, Mir N, Mousavi-Kamazani M, Bagheri S, Salavati-Niasari M
    Sci Rep, 2016 09 01;6:32539.
    PMID: 27581681 DOI: 10.1038/srep32539
    In this work, two natural sources, including pomegranate peel extract and cochineal dye were employed for the synthesis of silver nanoparticles. The natural silver complex from pomegranate peel extract resulted in nano-sized structures through solution-phase method, but this method was not efficient for cochineal dye-silver precursor and the as-formed products were highly agglomerated. Therefore, an alternative facile solid-state approach was investigated as for both natural precursors and the results showed successful production of well-dispersed nanoparticles with narrow size distribution for cochineal dye-silver precursor. The products were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy dispersive X-ray microanalysis (EDX), and Transmission Electron Microscopy (TEM).
    Matched MeSH terms: Food Coloring Agents/chemistry*
  4. Jawad AH, Azharul Islam M, Hameed BH
    Int J Biol Macromol, 2017 Feb;95:743-749.
    PMID: 27914966 DOI: 10.1016/j.ijbiomac.2016.11.087
    Fabrication of an immobilized cross-linked chitosan-epichlorohydrine thin film (CLCETF) onto glass plate for adsorption of reactive orange 16 (RO16) dye was successfully studied using the direct casting technique. Adsorption experiments were performed as a function of contact time, initial dye concentration (25mg/L to 350mg/L), and pH (3-11). The adsorption isotherm followed the Langmuir model. The adsorption capacity of CLECTF for RO16 was 356.50mg/g at 27±2°C. The kinetics closely followed the pseudo-second-order model. Results supported the potential use of an immobilized CLECTF as effective adsorbent for the treatment of reactive dye without using filtration process.
    Matched MeSH terms: Coloring Agents/chemistry*
  5. Liew RK, Azwar E, Yek PNY, Lim XY, Cheng CK, Ng JH, et al.
    Bioresour Technol, 2018 Oct;266:1-10.
    PMID: 29936405 DOI: 10.1016/j.biortech.2018.06.051
    A micro-mesoporous activated carbon (AC) was produced via an innovative approach combining microwave pyrolysis and chemical activation using NaOH/KOH mixture. The pyrolysis was examined over different chemical impregnation ratio, microwave power, microwave irradiation time and types of activating agents for the yield, chemical composition, and porous characteristic of the AC obtained. The AC was then tested for its feasibility as textile dye adsorbent. About 29 wt% yield of AC was obtained from the banana peel with low ash and moisture (<5 wt%), and showed a micro-mesoporous structure with high BET surface area (≤1038 m2/g) and pore volume (≤0.80 cm3/g), indicating that it can be utilized as adsorbent to remove dye. Up to 90% adsorption of malachite green dye was achieved by the AC. Our results indicate that the microwave-activation approach represents a promising attempt to produce good quality AC for dye adsorption.
    Matched MeSH terms: Coloring Agents/chemistry*
  6. Ahmad NA, Yook Heng L, Salam F, Mat Zaid MH, Abu Hanifah S
    Sensors (Basel), 2019 Nov 05;19(21).
    PMID: 31694284 DOI: 10.3390/s19214813
    A developed colorimetric pH sensor film based on edible materials for real-time monitoring of food freshness is described. The mixed natural dyes from edible plants Clitoria sp and Brassica sp were extracted and incorporated into ι-carrageenan film as a colorimetric pH sensor film for monitoring food spoilage and its freshness. The color changes of the developed colorimetric sensor film were measured with chromametry and UV-vis spectroscopy, respectively. Experimental results show that colorimetric pH sensor film demonstrated statistically significant differences (p < 0.05) between CIE-L*a*b* coordinates color system indicated that the developed colorimetric sensor film was able to give a gradual change in color over a wide pH range. The color of the colorimetric sensor film also changes discretely and linearly with factors that contribute to food spoilage using shrimp and durian samples. Moreover, the developed colorimetric pH sensor film has the potential to be used as a safe, non-destructive testing and also a flexibly visual method for direct assessment of food freshness indicator during storage.
    Matched MeSH terms: Coloring Agents/chemistry
  7. Oyekanmi AA, Ahmad A, Hossain K, Rafatullah M
    PLoS One, 2019;14(5):e0216878.
    PMID: 31091269 DOI: 10.1371/journal.pone.0216878
    The adsorption of rhodamine B (RhB) using acid modified banana peels has been examined. Chemical characteristics of the adsorbents were observed in order to determine active functional groups. The major functional groups on the surface were OH, C = O, C = C and C-O-C. Interactions between operational parameters were studied using the central composite design (CCD) of response surface methodology (RSM). The predictions of the model output indicated that operational factors influenced responses at a confidence level of 95% (P<0.05). The optimum conditions for adsorption were pH 2 at a 0.2 g/L dose within 60 minutes of contact time. Isotherm studies were carried out using the optimized process variables. The data revealed that RhB adsorption fitted the Langmuir isotherm equation while the reduction of COD followed the Freundlich isotherm. Kinetic experiments fitted the pseudo second order model for RhB removal and COD reduction. The adsorption mechanism was not the only rate controlling step. Diffusion through the boundary layer described the pattern of adsorption.
    Matched MeSH terms: Coloring Agents/chemistry*
  8. Wicaksono DH, Syazwani IN, Ratnarathorn N, Sadir S, Shahir S, Ruckthong L, et al.
    Bioanalysis, 2019 May;11(9):855-873.
    PMID: 31084195 DOI: 10.4155/bio-2018-0190
    Aim: Time-based microfluidic absorption sampling was proposed using cotton fiber-based device made in swab stick. The assay was optimized and compared with conventional pipetted drop sampling using the same device. Materials & methods: Reagents were integrated into cotton fiber device for assessing concentration of analytes by the colorimetric detection method through time-based absorption sampling microfluidic system. All assay parameters were first optimized using conventional pipette-based drop sampling. Results: The color intensity is linear in the relevant concentration range of the analytes. The LOD are 0.189 mM for glucose and 6.56 μM for nitrite, respectively. These values are better than conventional drop sampling. The fiber-containing swab itself functions as sampling, assay and calibration device. Conclusion: Microfluidic cotton fiber-based assay device was fabricated and can determine analyte concentration in artificial salivary samples, colorimetrically, by time-based absorption sampling without the need of complex equipments.
    Matched MeSH terms: Food Coloring Agents/chemistry
  9. Jawad AH, Norrahma SSA, Hameed BH, Ismail K
    Int J Biol Macromol, 2019 Aug 15;135:569-581.
    PMID: 31150675 DOI: 10.1016/j.ijbiomac.2019.05.127
    In this work, chitosan (Chi) was cross-linked with glyoxal (Gly) and deposited onto glass plate to be a superior adsorbent film for two structurally different reactive orange 16 (RO-16) and methyl orange (MO) dyes by using non-conventional adsorption system without filtration process. The characterizations indicate that the cross-linked chitosan-glyoxal (Chi-Gly) film has a low swelling index, high adherence strength on glass plate, amine group (NH2) content was 32.52%, and pHpzc of ∼6.0 indicating a negative surface charge occurs above pHpzc. The adsorption isotherm data of RO-16 and MO by Chi-Gly film were in agreement with Langmuir isotherm, with maximum adsorption capacities of 1554.3 mg/g and 1451.9 mg/g, respectively. The pseudo-first-order kinetic model best described the kinetic data. The adsorption process was spontaneous and exothermic in nature at Chi-Gly film thickness of 8.55 μm, and pH ~3. The mechanism of adsorption included mainly electrostatic attractions, dipole-dipole hydrogen bonding interactions, n-π stacking attractions, and Yoshida H-bonding. This study reveals that immobilized Chi-Gly film as a good candidate for adsorption of reactive and acid dyes as it does not require any filtration process and adsorbent recovery during and post-adsorption process.
    Matched MeSH terms: Coloring Agents/chemistry*
  10. Sadiq AC, Olasupo A, Ngah WSW, Rahim NY, Suah FBM
    Int J Biol Macromol, 2021 Nov 30;191:1151-1163.
    PMID: 34600954 DOI: 10.1016/j.ijbiomac.2021.09.179
    The presence of dyes in the aquatic environment as a result of anthropogenic activities, especially textile industries, is a critical environmental challenge that hinders the availability of potable water. Different wastewater treatment approaches have been used to remediate dyes in aquatic environments; however, most of these approaches are limited by factors ranging from high cost to the incomplete removal of the dyes and contaminants. Thus, the use of adsorption as a water treatment technology to remove dyes and other contaminants has been widely investigated using different adsorbents. This study evaluated the significance of chitosan as a viable adsorbent for removing dyes from water treatment. We summarised the literature and research results obtained between 2009 and 2020 regarding the adsorption of dyes onto chitosan and modified chitosan-based adsorbents prepared through physical and chemical processing, including crosslinking impregnation, grafting, and membrane preparation. Furthermore, we demonstrated the effects of various chitosan-based materials and modifications; they all improve the properties of chitosan by promoting the adsorption of dyes. Hence, the application of chitosan-based materials with various modifications should be considered a cutting-edge approach for the remediation of dyes and other contaminants in aquatic environments toward the global aim of making potable water globally available.
    Matched MeSH terms: Coloring Agents/chemistry*
  11. Samrot AV, Saigeetha S, Mun CY, Abirami S, Purohit K, Cypriyana PJJ, et al.
    Sci Rep, 2021 12 31;11(1):24511.
    PMID: 34972829 DOI: 10.1038/s41598-021-03328-2
    Latex, a milky substance found in a variety of plants which is a natural source of biologically active compounds. In this study, Latex was collected from raw Carica papaya and was characterized using UV-Vis, FTIR and GC-MS analyses. Super Paramagnetic Iron Oxide Nanoparticles (SPIONs) were synthesized, coated with C. papaya latex (PL-Sp) and characterized using UV-Vis, FT-IR, SEM-EDX, XRD, VSM and Zeta potential analyses. SPIONs and latex coated SPIONs (PL-Sp) were used in batch adsorption study for effective removal of Methylene blue (MB) dye, where (PL-Sp) removed MB dye effectively. Further the PL-Sp was used to produce a nanoconjugate loaded with curcumin and it was characterized using UV-Vis spectrophotometer, FT-IR, SEM-EDX, XRD, VSM and Zeta potential. It showed a sustained drug release pattern and also found to have good antibacterial and anticancer activity.
    Matched MeSH terms: Coloring Agents/chemistry*
  12. García JR, Sedran U, Zaini MAA, Zakaria ZA
    Environ Sci Pollut Res Int, 2018 Feb;25(6):5076-5085.
    PMID: 28391459 DOI: 10.1007/s11356-017-8975-8
    Palm oil mill wastes (palm kernel shell (PKS)) were used to prepare activated carbons, which were tested in the removal of colorants from water. The adsorbents were prepared by 1-h impregnation of PKS with ZnCl2 as the activating agent (PKS:ZnCl2 mass ratios of 1:1 and 2:1), followed by carbonization in autogenous atmosphere at 500 and 550 °C during 1 h. The characterization of the activated carbons included textural properties (porosity), surface chemistry (functional groups), and surface morphology. The dye removal performance of the different activated carbons was investigated by means of the uptake of methylene blue (MB) in solutions with various initial concentrations (25-400 mg/L of MB) at 30 °C, using a 0.05-g carbon/50-mL solution relationship. The sample prepared with 1:1 PKS:ZnCl2 and carbonized at 550 °C showed the highest MB adsorption capacity (maximum uptake at the equilibrium, q max = 225.3 mg MB / g adsorbent), resulting from its elevated specific surface area (BET, 1058 m2/g) and microporosity (micropore surface area, 721 m2/g). The kinetic experiments showed that removals over 90% of the equilibrium adsorptions were achieved after 4-h contact time in all the cases. The study showed that palm oil mill waste biomass could be used in the preparation of adsorbents efficient in the removal of colorants in wastewaters.
    Matched MeSH terms: Coloring Agents/chemistry*
  13. 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: Coloring Agents/chemistry*
  14. Razak IS, Latif MT, Jaafar SA, Khan MF, Mushrifah I
    Environ Sci Pollut Res Int, 2015 Apr;22(8):6024-33.
    PMID: 25382497 DOI: 10.1007/s11356-014-3781-z
    This study was conducted to determine the composition of surfactants in atmospheric aerosols and rainwater in the vicinity of Lake Chini, Malaysia. Samples of atmospheric aerosol and rainwater were collected between March and September 2011 using a high volume air sampler (HVAS) and glass bottles equipped with funnel. Colorimetric analysis was undertaken to determine the concentration of anionic surfactants as methylene blue active substances (MBAS) and cationic surfactants as disulphine blue active substances (DBAS). The water-soluble ionic compositions were determined using inductively coupled plasma mass spectrometry for cations (Na, K, Mg and Ca) and ion chromatography equipped with a conductivity detector for anions (F(-), Cl(-), NO3(-), and SO4(2-)) and the Nessler Method was used to obtain the NH4(+) concentrations. The source apportionment of MBAS and DBAS in atmospheric aerosols was identified using a combination of principal component analysis (PCA) and multiple linear regression (MLR). The results revealed that the concentrations of surfactants in atmospheric aerosols and rainwater were dominated by anionic surfactants as MBAS. The concentration of surfactants as MBAS and DBAS was dominated in fine mode compared to coarse mode aerosols. Using PCA/MLR analysis, two major sources of atmospheric surfactants to Lake Chini were identified as soil dust (75 to 93%) and biomass burning (2 to 22%).
    Matched MeSH terms: Coloring Agents/chemistry
  15. Harivaindaran KV, Rebecca OP, Chandran S
    Pak J Biol Sci, 2008 Sep 15;11(18):2259-63.
    PMID: 19137837
    The peel of Hylocereus polyrhizus is often regarded as a waste hence this study was aimed at exploring the feasibility of using the peel as a natural colorant using simple water extraction method. Samples were subjected to a series of temperatures: Room temperature (RT), 50, 80 and 100 degrees C; varied length of heating time from 1, 2, 3, 4, 5 and 10 min and a varied range of pH using 1 M of citric acid solution. The best condition to obtain highest betacyanin content was heating samples at 100 degrees C for 5 min in a pH 5 citric acid solution. The next part of this study involved the stability test of the pigments obtained through the best method determined earlier. The pigments were dried and resuspended in distilled water. The samples were then exposed to light to monitor pigment changes. Initial resuspension of the dried pigments yielded a comparable high content of betacyanins to its juice counterpart. The results showed that resuspended pigments had high pigment retention and were stable up to 7 days. These initial findings must be further studied in more controlled conditions to understand the stability of betacyanin. Nevertheless, the results show that betacyanin obtained from the peel of dragon fruit has a high potential to be used as a natural dye.
    Matched MeSH terms: Food Coloring Agents/chemistry*
  16. Hapiz A, Jawad AH, Wilson LD, ALOthman ZA
    Int J Phytoremediation, 2024 Feb;26(3):324-338.
    PMID: 37545130 DOI: 10.1080/15226514.2023.2241912
    In this investigation, microwave irradiation assisted by ZnCl2 was used to transform pineapple crown (PN) waste into mesoporous activated carbon (PNAC). Complementary techniques were employed to examine the physicochemical characteristics of PNAC, including BET, FTIR, SEM-EDX, XRD, and pH at the point-of-zero-charge (pHpzc). PNAC is mesoporous adsorbent with a surface area of 1070 m2/g. The statistical optimization for the adsorption process of two model cationic dyes (methylene blue: MB and, crystal violet: CV) was conducted using the response surface methodology-Box-Behnken design (RSM-BBD). The parameters include solution pH (4-10), contact time (2-12) min, and PNAC dosage (0.02-0.1 g/100 mL). The Freundlich and Langmuir models adequately described the dye adsorption isotherm results for the MB and CV systems, whereas the pseudo-second order kinetic model accounted for the time dependent adsorption results. The maximum adsorption capacity (qmax) for PNAC with the two tested dyes are listed: 263.9 mg/g for CV and 274.8 mg/g for MB. The unique adsorption mechanism of MB and CV dyes by PNAC implicates multiple contributions to the adsorption process such as pore filling, electrostatic forces, H-bonding, and π-π interactions. This study illustrates the possibility of transforming PN into activated carbon (PNAC) with the potential to remove two cationic dyes from aqueous media.
    Matched MeSH terms: Coloring Agents/chemistry
  17. Ho LN, Ong SA, Osman H, Chong FM
    J Environ Sci (China), 2012;24(6):1142-8.
    PMID: 23505883
    Fish scale (FS) loaded TiO2 composites were investigated as photocatalysts in degradation of Methyl Orange under solar light irradiation. Composites were prepared through sol-gel method by varying mass ratio of TiO2/FS at 90:10, 70:30 and 50:50, respectively. The catalysts prepared in this study were characterized by using XRD, SEM, FT-IR and nitrogen sorption. The effects of solar irradiation, mass ratio of TiO2/FS composites, irradiation time and catalyst loadings were studied. Synergistic effect was found in TiO2/FS of 90:10 composite which performed higher photocatalytic degradation than synthesized TiO2 under solar light irradiation. However, further increasing fish scale content in the composites reduced the photocatalytic activity drastically. Under solar light irradiation, all the catalysts in this study exhibited photocatalytic activity, except TiO2/FS of 50:50 composite that only acted as a weak biosorbent without performing any photocatalytic property. Photocatalytic degradation increased with increasing catalyst loading and irradiation time but decreased with increased of initial dye concentration.
    Matched MeSH terms: Coloring Agents/chemistry*
  18. Ahmad AA, Hameed BH
    J Hazard Mater, 2010 Mar 15;175(1-3):298-303.
    PMID: 19883979 DOI: 10.1016/j.jhazmat.2009.10.003
    In this work, the adsorption potential of bamboo waste based granular activated carbon (BGAC) to remove C.I. Reactive Black (RB5) from aqueous solution was investigated using fixed-bed adsorption column. The effects of inlet RB5 concentration (50-200mg/L), feed flow rate (10-30 mL/min) and activated carbon bed height (40-80 mm) on the breakthrough characteristics of the adsorption system were determined. The highest bed capacity of 39.02 mg/g was obtained using 100mg/L inlet dye concentration, 80 mm bed height and 10 mL/min flow rate. The adsorption data were fitted to three well-established fixed-bed adsorption models namely, Adam's-Bohart, Thomas and Yoon-Nelson models. The results fitted well to the Thomas and Yoon-Nelson models with coefficients of correlation R(2)>or=0.93 at different conditions. The BGAC was shown to be suitable adsorbent for adsorption of RB5 using fixed-bed adsorption column.
    Matched MeSH terms: Coloring Agents/chemistry*
  19. Hameed BH
    J Hazard Mater, 2009 Jan 30;161(2-3):753-9.
    PMID: 18499346 DOI: 10.1016/j.jhazmat.2008.04.019
    In the present study, spent tea leaves (STL) were used as a new non-conventional and low-cost adsorbent for the cationic dye (methylene blue) adsorption in a batch process at 30 degrees C. Equilibrium sorption isotherms and kinetics were investigated. The experimental data were analyzed by the Langmuir, Freundlich and Temkin models of adsorption. The adsorption isotherm data were fitted well to the Langmuir isotherm and the monolayer adsorption capacity was found to be 300.052mg/g at 30 degrees C. The kinetic data obtained at different initial concentrations were analyzed using pseudo-first-order, pseudo-second-order and intraparticle diffusion equations. The results revealed that the spent tea leaves, being waste, have the potential to be used as a low-cost adsorbent for the removal of methylene blue from aqueous solutions.
    Matched MeSH terms: Coloring Agents/chemistry
  20. Hameed BH, El-Khaiary MI
    J Hazard Mater, 2008 Jun 15;154(1-3):237-44.
    PMID: 18022316
    Oil palm trunk fibre (OPTF)--an agricultural solid waste--was used as low-cost adsorbent to remove malachite green (MG) from aqueous solutions. The operating variables studied were contact time, initial dye concentration, and solution pH. Equilibrium adsorption data were analyzed by three isotherms, namely the Freundlich isotherm, the Langmuir isotherm, and the multilayer adsorption isotherm. The best fit to the data was obtained with the multilayer adsorption. The monolayer adsorption capacity of OPTF was found to be 149.35 mg/g at 30 degrees C. Adsorption kinetic data were modeled using the Lagergren pseudo-first-order, Ho's pseudo-second-order and Elovich models. It was found that the Lagergren's model could be used for the prediction of the system's kinetics. The overall rate of dye uptake was found to be controlled by external mass transfer at the beginning of adsorption, then for initial MG concentrations of 25, 50, 100, 150, and 300 mg/L the rate-control changed to intraparticle diffusion at a later stage, but for initial MG concentrations 200 and 250 mg/L no evidence was found of intraparticle diffusion at any period of adsorption. It was found that with increasing the initial concentration of MG, the pore-diffusion coefficient increased while the film-diffusion coefficient decreased.
    Matched MeSH terms: Coloring Agents/chemistry*
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