Now showing 1 - 10 of 29
  • Publication
    Biotreatment of sulfonated dyestuffs with energy recovery in microbial fuel cell: Influencing parameters, kinetics, degradation pathways, mechanisms, and phytotoxicity assessment
    ( 2021-08-01)
    Tan S.M.
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    ; ;
    Wong Y.S.
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    Thung W.E.
    ;
    Teoh T.P.
    Removal of recalcitrant sulfonated dyestuff intermediates from wastewater has been an urgent challenge for environmental technologies. In this regard, the biodegradations of monoazo Methyl Orange (MO) and diazo dyes Reactive Black 5 (RB5) towards wastewater treatment and bioelectricity generation in microbial fuel cell were investigated and compared through the studies on azo dye concentration, aeration, sampling points arrays, and electrode spacings. The degradation of diazo RB5 yielded higher chemical oxygen demand removal, decolourization efficiencies, and power generation over monoazo MO. The decolourization efficiency of RB5 (97.62%) increased with an increase of RB5 concentration (50 mg/L), suggesting that the system has the capability of removing higher RB5 concentration. However, contrary results were obtained with MO due to its toxicity. This study also demonstrated that the decolourization rate of diazo RB5 (0.1533 h-1) was ≈ 53% higher than monoazo MO (0.0727 h-1). The findings revealed that the degradation kinetic was remarkably influenced by the chemical structure of dye, where dye with more electron-withdrawing groups at para position are more susceptible to be reduced. Higher output voltage (568.59 mV) and power generation (108.87 mW/m2) were attained with RB5 due to electron donor availability and electron-shuttling characteristics of RB5 decolourized intermediates. Furthermore, detailed degradation pathways of MO and RB5 were presented based on the UV-vis and GC-MS results. The phytotoxicity assessment via Sorghum bicolor seeds had further verified the reduction in toxicity after the treatment of azo dyes.
  • Publication
    Removal of dyes from industrial effluents using combination of Advanced Oxidation Processes (AOPs) and biological treatment
    Nowadays, the removal of dyes from industrial effluents is still far away to a satisfactory solution. Even though the AOPs are known strong technologies for wastewater treatment, it still requires further advancement and extent. Hence, a new promising treatment is their combination with biological treatment, by taking the advantages of the individual potentials. Therefore, this research evaluated four treatment techniques, namely ozonation, ozone/hydrogen peroxide (O3/H2O2), ultraviolet/hydrogen peroxide (UV/H2O2), and a combination of ozonation-biological for synthetic dyes, consist of monoazo Methyl Orange (MO), disazo Reactive Red 120 (RR120) and anthraquinone Reactive Blue 19 (RB19). Finally, the treatments are evaluated with batik wastewater as a real wastewater sample from industries. The finding revealed that ozonation, O3/H2O2, UV/H2O2, and ozonation-biological become an effective treatment for monoazo, disazo, anthraquinone, and real wastewater. The treatments accomplish, under appropriate conditions, a full decolourization and a substantial mineralization. However, O3/H2O2 and ozonation works well with the dyes, in contrast to UV/H₂O₂. It reveals that complete decolourization by ozonation and O3/H2O2, with less than 20 min contact. Two decolourization curves of ozonation and O3/H2O2 almost overlapped suggesting that H2O2 hardly affects decolourization rate. Contrariwise, it takes more than 60 min for complete decolourization with UV/H₂O₂ for RR120, but requires more than 120 min for MO and RB19. Nevertheless, there was a significant difference for COD and TOC removals. It is apparent that O₃/H₂O₂ showed higher removal, suggesting that the presence of H₂O₂ promote the oxidation reaction. The final COD removal of O₃/H₂O₂ reached 100% within less than 10 min for RR120 and RB19, while 15 min for MO. Likewise, the higher TOC removal was observed for O₃/H₂O₂ in comparison to ozonation and UV/H₂O₂. On the whole, the COD removal was similar to TOC removal for each treatment. It is obvious that high decolourization from the start of biological was contributed from ozonation pre-treatment. In addition, the results indicate that 59.6 and 69.4% COD removal from ozonation and ozonationbiological, respectively for MO. While, resulted about 40.7 and 72.9% removal for RR120, and 51.4 and 59.8% for RB19, respectively. Thus, it represents small organic molecules that contribute considerably to the COD that cannot be completely removed by ozonation-biological treatment. Similar to COD, the results indicate that 49.1 and 73.7% TOC removal from ozonation and ozonation-biological, respectively for MO. While it leads to 39.3 and 64.3% removal for RR120 and 37.5 and 70.8% removal for RB19, respectively. It is clear that the biological further degrades the dyes from ozonation. In addition, each dye shows different decolourization pattern and degradation behaviour according to its chemical structure. The change in UV-vis and FT-IR spectra indicated the evidence of dye structure cleavage and intermediates formation. While, the NO₃-, SO₄2- and Cl- anions formed indicate dye mineralization. The decolourization conform first-order kinetics, with R2 values greater than 0.92. The O₃/H₂O₂ performs better with the batik wastewater, as compared to ozonation and UV/H₂O₂. Therefore, the results for synthetic wastewater support its application for real wastewater, even though the batik wastewater was more difficult to be decolourized and degraded because of its complex composition.
      2  15
  • Publication
    Reactive Green 19 degradation using O3/S2 O8(2-) process: Intermediates and proposed degradation pathway
    ( 2022-01-01)
    Mohd Razali N.A.
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    ; ; ; ;
    Siti Nasuha Sabri
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    Kow Su Huan
    ;
    Safya Abdul Malik
    The massive drawbacks of conventional wastewater treatment have led to a demand investigation about new advanced wastewater treatment technology. The issue can be addressed via advanced oxidation processes (AOPs) as witnessed recently. Therefore, the objective of this study was to investigate the performance of ozone/persulfate ((Formula presented.)) process to assess its use as potential degradation of diazo dye which is Reactive Green 19 (RG19). In this work, efficiency, color, and COD removal were investigated over a range of initial pH, persulfate concentration and initial concentration of RG19. The amount of sodium persulfate ((Formula presented.)) was varied at different levels (20–100 mM) relative to precursor radical to assess the optimum usage of persulfate concentration for RG19 degradation. Evidence that RG19 could degrade efficiently had occurred at 100 mg/L, initial pH 9, 60 mM persulfate concentration was identified by FTIR and GC/MS analysis. The results revealed that RG19 could achieve complete decolorization easily as compared to mineralization. In addition, RG19 degradation pathway gave the best representation of level degradation. The GC/MS and FTIR results exhibited the proposed RG19 degradation pathway that involved the characteristic of sulfonic group, (Formula presented.) accompanied with (Formula presented.) became as an indicator of their structure broken down one by one. The degradation products such as oxalic acid, formic acids and others were analyzed and finally converted to carbon dioxide and water. The diazo dye structure itself aided with (Formula presented.) has its superior characteristic as an aid for the efficient degradation process.
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  • Publication
    Influence of leachate matrix on oxidation performance of ozonation and aops
    Landfill leachate is a critical environmental issue that should be adequately treated to prevent it from spreading to the environment. This study explored the influence of raw leachate matrix and treated leachate matrix on O3, O3/H2O2, and O3/PS performance. O3 and AOPs were conducted in a laboratory-scale batch reactor. The findings showed the degradation of p-cresol, COD, and humic substances was much slower in treated leachate matrix than in raw leachate matrix. However, color was found easier to remove in treated leachate. The results revealed a synergic effect between molecular O3 and dissolved organic matter in the raw leachate as the O3 performance was enhanced in the presence of raw leachate matrix, except for color removal. The highest degradation of more than 90% was achieved in O3 /H2 O2 to remove COD, p-cresol, and humic substances, although it is the most affected by the leachate matrix. This study provides vital insight into the notable performance of O3 /PS in color removal regardless of the influence of leachate matrix, suggesting that the sulfate radical-induced oxidation outperformed O3 and O3 /H2 O2 in reducing nitrogen-containing compounds.
      1  39
  • Publication
    The effect of iron doping on ZnO catalyst on dye removal efficiency
    Dyes often being use in many manufacturing processes. Hence, the wastewater resulted from the manufacturing process contain colour which need to be removed before being emitted into any water bodies. Photocatalysis is a method which effectively treating wastewater using photocatalyst. ZnO is an example of semiconductor material which is use as a photocatalyst in the treatment method. Doping with transition metals can improve its properties to maximize its photocatalytic efficiency. In this study, the effect of zinc oxide (ZnO) and zinc oxide doped Fe (ZnO/Fe) photocatalyst for dye removal efficiency were investigated. The photocatalysts were successfully synthesized through sol-gel method and characterized by SEM, FTIR and EDX. The photocatalytic efficiency of ZnO and ZnO/Fe was studied by degrading methylene blue (MB) under the exposure of 3 hours of sunlight with varies operational condition. Optimal photocatalytic efficiency operating parameters were performed by Design Expert 10 using the Response Surface Method (RSM). ZnO appeared as regular shape compared to ZnO/Fe which most of the particles had clumped together. The removal efficiency of MB was increase when the dosage of catalyst increased. However, once the optimum dosage of catalyst exceeded, the removal efficiency of MB reduced. During the experiment, 30 mg of ZnO was capable to remove 90% of MB from the solution. When while, ZnO/Fe exhibited better result as it could remove up to 95% of MB using only 10 mg of ZnO/Fe during the treatment. It can be concluded that doping the ZnO with Fe could improve the catalytic ability of ZnO to degrade MB in wastewater.
      29  2
  • Publication
    Preliminary screening oxidative degradation methyl orange using ozone/ persulfate
    ( 2018)
    Nur Aqilah Razali
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    ; ; ; ;
    Siti Nasuha Sabri
    ;
    Su Huan Kow
    The present study focusing on the performances of advanced oxidation process by using ozonation method towards Methyl Orange based on the efficiency of colour removal and Chemical Oxygen Demand (COD) removal. Factorial design with response surface methodology (RSM) was used to evaluate the interaction between operational conditions, such as pH, initial concentration, contact time and persulfate dosage to obtain the optimum range conditions using a semi-batch reactor. The range of independent variables investigated were pH (3-11), initial concentration (100-500mg/L), contact time (10-50min) and persulfate dosage (20-100mM) while the response variables were colour removal and COD removal of Methyl Orange. The experimental results and statistical analysis showed all the parameters were significant. Thus, from this findings, optimization of operational conditions that had been suggested from the ozone/persulfate RSM analysis were (pH 3, 100 mg/L, 50min, 60mM) that would be produced 99% Colour Removal and 80% COD Removal and help in promoting an efficient ozonation process. The effect list data that showed the most contributed effects to increase the percentages of colour removal were pH and persulfate dosage whereas the contact time and initial concentration had the highest positive effects on the COD removal. Other than that, the interaction between pH, contact time and persulfate dosage were found to be the most influencing interaction. Therefore the least influencing interaction was interaction between persulfate dosage and pH. In this study, the correlation coefficient value R2 for colour removal and COD removal of Methyl Orange were R2= 0.9976 and R2= 0.9924 which suggested a good fit of the first-order regression model with the experimental data.
      6  23
  • Publication
    A hybrid photocatalytic fuel cell integrated electro-Fenton system for Amaranth dye degradation and electricity generation
    A dual-chambered hybrid system of photocatalytic fuel cell (PFC) and electro-Fenton (EF) process has become an emerging sustainable green approach for organic pollutant degradation and electricity generation. This hybrid system of PFC and EF (PFC-EF hybrid system) is an integration of two popular organic pollutants treatment methods, PFC and EF process. The double-cathodes configuration of PFC-EF hybrid system enhanced the oxygen reduction reaction reactivity in both PFC and EF. PFC-EF hybrid system with double cathodes achieved colour removal efficiencies of 86.2% and 84.7% in PFC and EF. Power density of 1.2211 μW cm-2 was obtained in this PFC-EF hybrid system. Results revealed that this PFC-EF hybrid system was effective in the Amaranth dye degradation and power production simultaneously.
      4  15
  • Publication
    Unravelling the Performance of Microbial Fuel Cell for Simultaneous Binary Dyes Remediation and Bioelectricity Generation
    ( 2022-01-01)
    Tan S.M.
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    ;
    Wong Y.S.
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    ; ;
    Noor N.M.
    ;
    Moncea A.
    This study was to examine the bioremediation of wastewater containing a binary mixture of methyl orange (MO) and reactive black 5 (RB5), as well as bioelectricity generation in single chamber up-flow membrane-less microbial fuel cell (UFML-MFC). Decolourisation performance and power density of MFC were studied with different concentrations of binary dye (25, 50 and 75 mg/L) as influent. The colour removals evaluated from the standard curve of dye against optical density at its maximum absorption wavelength were 80.40%, 70.33% and 56.99%, respectively in the three phases of study. The decolourisation extent of RB5 is comparatively higher than MO in the binary mixture, due to the presence of more sulphonate groups in the molecular geometry of RB5. The reductive cleavage of azo bond was denoted by UV spectroscopic analysis.
      1  18
  • Publication
    Influence of leachate matrix on oxidation performance of ozonation and aops
    Landfill leachate is a critical environmental issue that should be adequately treated to prevent it from spreading to the environment. This study explored the influence of raw leachate matrix and treated leachate matrix on O3, O3/H2O2, and O3/PS performance. O3 and AOPs were conducted in a laboratory-scale batch reactor. The findings showed the degradation of p-cresol, COD, and humic substances was much slower in treated leachate matrix than in raw leachate matrix. However, color was found easier to remove in treated leachate. The results revealed a synergic effect between molecular O3 and dissolved organic matter in the raw leachate as the O3 performance was enhanced in the presence of raw leachate matrix, except for color removal. The highest degradation of more than 90% was achieved in O3 /H2 O2 to remove COD, p-cresol, and humic substances, although it is the most affected by the leachate matrix. This study provides vital insight into the notable performance of O3 /PS in color removal regardless of the influence of leachate matrix, suggesting that the sulfate radical-induced oxidation outperformed O3 and O3 /H2 O2 in reducing nitrogen-containing compounds.
      2  47
  • Publication
    Treatment of O3 with Na2S2O8 by ANOVA Interpretation towards degradation of azo dye
    Advanced oxidation processes (AOPs) especially ozonation method is widely studied in the wastewater treatmentfield. In this study, it highlighted about threemainenvironmental issues in the world such as1) proposing a method to overcome uncontrollable effluents from textile industriesby using syntheticdyes; 2)creating an improvementof previous conventional method; 3) reduced process time by using statistical approach.To address with this issue, analysis of variance (ANOVA)from Response Surface Methodology (RSM)to study the performance of O3with the help of persulfate (Na2S2O8) for treating one of azo dyes which is Reactive Green 19.This is due to there isvery limited work done by statistical analysis on this study. Hence, ANOVA data would proposestatistical models tailored to the data in 2D and 3D contour plots by knowing the three influenced parameterswhich is pH(6 to 10),persulfate concentration (30to 70mM) and contact time (4 to 20 min). Through the analysis, the result can be concluded that improvement of ozonation process with persulfate (Na2S2O8) werestatistically significant after allinteractive effectsgave a positive feedback towards responses.The obtained optimum conditions included a persulfate concentration (49mM), initial pH (8.89) and contact time (18 min) with fixed initial concentration 100mg/L. The experimental results were corresponded well with predicted models colour removal rates which is 99%.
      1  19