scholarly journals Electrochemical Degradation of Methylene Blue using a Ni-Co-oxide Anode

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 793
Author(s):  
Emmanuel Onyekachi Nwanebu ◽  
Xiaocheng Liu ◽  
Elmira Pajootan ◽  
Viviane Yargeau ◽  
Sasha Omanovic
Keyword(s):  
Methylene Blue ◽  
Organic Contaminants ◽  
Uv Spectroscopy ◽  
Organic Pollutant ◽  
Oxygen Demand ◽  
Active Species ◽  
Chloride Ions ◽  
Blue Dye ◽  
Electrochemical Degradation ◽  
Oxide Anode

The potential of using thermally prepared Ni0.6Co0.4-oxide for the electrochemical degradation of organic contaminants was investigated using methylene blue (MB) in an aqueous solution, as a model pollutant. The results of UV spectroscopy obtained during galvanostatic electrolyses at the anode indicated the complete removal of the methylene blue dye. The high removal of chemical oxygen demand (COD) and total organic carbon (TOC) suggested a high level of mineralization of its intermediates. It was found that the electrocatalytic performance of the electrode in the anodic degradation of the organic pollutant was significantly enhanced by the presence of chloride ions in the solution. The improvement in the degradation rate of MB was attributed to the in situ electrogeneration of chlorine active species. The results show that Ni0.6Co0.4-oxide anode can be employed as a stable energy-efficient electrocatalyst in the electrochemical purification of wastewater.

Influence of chloride ions on organic contaminants decolorization through the Fe0-activated persulfate oxidation process: efficiency and intermediates

2019 ◽  
Vol 80 (3) ◽  
pp. 563-574 ◽  
Author(s):  
Feng Ding ◽  
Yong Xie ◽  
Tengyan Wu ◽  
Na Liu
Keyword(s):  
Organic Contaminants ◽  
Oxidation Process ◽  
Operating Cost ◽  
Oxygen Demand ◽  
Transformation Products ◽  
Chloride Ions ◽  
Process Efficiency ◽  
Persulfate Oxidation ◽  
By Products ◽  
Activated Persulfate

Abstract This study was conducted to evaluate the influence of chloride ions (Cl−) on organic contaminants decolorization by the Fe0-activated persulfate process (PS/Fe0), as well as the generation of transformation products. Orange II (OII) was chosen as the target pollution. The results indicated that Cl− influenced the OII decolorization by PS/Fe0 system, resulting in the generation of chlorine-containing by-products. OII containing Cl− solution can be efficiently decolorized by PS/Fe0 process, and the decolorization efficiencies changed depending on Cl− concentration due to the reaction between Cl− and sulfate radicals (SO4–•). The operating cost for 94% color and 64% chemical oxygen demand (COD) removal of the OII dye was estimated at 0.73 USD/m3. The chlorine-containing by-products, such as chlorobenzene, 3,5-dichloro-benzene-1,2-diol, and 2,3-dichloro-2,3-dihydro-1,4-naphthoquinone, were generated during the reaction. The results further indicated that increasing both PS concentration and temperature enhanced OII decolorization and reduced the generation of chlorine-containing intermediates. The addition of ultrasound can further decrease the generation of chlorine-containing intermediates under high-temperature conditions. The proposed pathways of decolorization of OII containing Cl− also indicated that SO4–• dominated the OII degradation, while the presence of Cl− led to the generation of chlorine-containing intermediates.

Assessing the effectiveness of green synthetized silver nanoparticles with Cryptocarya alba extracts for remotion of the organic pollutant methylene blue dye

2019 ◽  
Vol 26 (15) ◽  
pp. 15115-15123 ◽  
Author(s):  
Gonzalo Recio-Sánchez ◽  
Ricardo Tighe-Neira ◽  
Claudia Alvarado ◽  
Claudio Inostroza-Blancheteau ◽  
Noelia Benito ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Silver Nanoparticles ◽  
Organic Pollutant ◽  
Blue Dye ◽  
Methylene Blue Dye

scholarly journals Bifunctional g-C3N4/WO3 Thin Films for Photocatalytic Water Purification

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2439 ◽  
Author(s):  
Maria Antoniadou ◽  
Michalis K. Arfanis ◽  
Islam Ibrahim ◽  
Polycarpos Falaras
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Dye Degradation ◽  
Active Species ◽  
Blue Dye ◽  
Pseudo First Order Reaction ◽  
Uv Illumination ◽  
Bilayered Structure ◽  
Reaction Constants

A bifunctional thin film photocatalyst consisting of graphitic carbon nitride on tungsten trioxide (g-C3N4/WO3) is introduced for the improvement of photocatalytic activity concerning hexavalent chromium reduction and methylene blue dye removal in water, compared to the bare, widely used WO3 semiconductor. A bilayered structure was formed, which is important for the enhancement of the charge carriers’ separation. The characterization of morphological, structural, optoelectronic, and vibrational properties of the photocatalysts permitted a better understanding of their photocatalytic activity for both dye degradation and Cr+6 elimination in water and the analysis of the photocatalytic kinetics permitted the determination of the corresponding pseudo-first-order reaction constants (k). Trapping experiments performed under UV illumination revealed that the main active species for the photocatalytic reduction of Cr+6 ions are electrons, whereas in the case of methylene blue azo-dye (MB) oxidation, the activation of the corresponding photocatalytic degradation comes via both holes and superoxide radicals.

One-step Solvothermal Synthesis of rGO/TiO2 Nanocomposite for Efficient Solar Photocatalytic Degradation of Methylene Blue Dye

2018 ◽  
Vol 15 (2) ◽  
pp. 157-162 ◽  
Author(s):  
Valerie Ling Er Siong ◽  
Chin Wei Lai ◽  
Joon Ching Juan ◽  
Kian Mun Lee ◽  
Bey Fen Leo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Methylene Blue ◽  
Graphene Oxide ◽  
Organic Contaminants ◽  
Primary Objective ◽  
Blue Dye ◽  
Light Illumination ◽  
Potential Candidate ◽  
Adsorption Sites ◽  
One Step

Background: The discharge of effluents from the textile and dyeing industries has been a worldwide concern. Although reduced graphene oxide/titanium dioxide (rGO/TiO2) nanocomposite is a potential candidate for wastewater treatment, the influence of graphene oxide (GO) content on its physico-chemical characteristics and its subsequent photocatalytic capabilities in degrading the organic contaminants has not been well established. Objective: The primary objective of this study was to assess the use of rGO/TiO2 nanocomposites with various GO contents for the removal of toxic methylene blue (MB) dye from aqueous solution. Method: In the present study, rGO/TiO2 nanocomposites were fabricated using various GO contents through a one-step solvothermal method. The effect of GO content on the nanocomposite formation was investigated by using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy. The resulting nanocomposites were evaluated against MB degradation under artificial solar light illumination. Results: Based on the photocatalytic results, the highest removal percentage of MB was achieved by 0.15rGO/TiO2, which was about 1.7 times higher than that of 0.01rGO/TiO2. The enhanced removal efficiency of MB by the nanocomposite with the highest GO content (0.15 g) was attributed to the increased active adsorption sites, which greatly promoted the π- π interaction between the aromatic rings of MB dye and the graphitic skeleton of rGO, as well as the electrostatic interaction between the cationic center of MB molecules and the residual oxygen functionalities of rGO.

scholarly journals Photocatalytic Porous Silica-Based Granular Media for Organic Pollutant Degradation in Industrial Waste-Streams

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 258
Author(s):  
Hannah M. McIntyre ◽  
Megan L. Hart
Keyword(s):  
Methylene Blue ◽  
Organic Contaminants ◽  
Granular Media ◽  
Pore Space ◽  
Organic Pollutant ◽  
Salt Content ◽  
Porous Silica ◽  
Cost Effective ◽  
High Porosity ◽  
Activation Temperature

Photocatalytic treatment of organic contaminants in industrial wastewaters has gained interest due to their potential for effective degradation. However, photocatalytic slurry reactors are hindered by solution turbidity, dissolved salt content, and absorbance of light. Research presented here introduces the development and application of a novel, photocatalytic, porous silica-based granular media (SGM). SGM retains the cross-linked structure developed during synthesis through a combination of foaming agent addition and activation temperature. The resultant media has a high porosity of 88%, with a specific surface area of ~150 m2/gram. Photocatalytic capabilities are further enhanced as the resultant structure fixes the photocatalyst within the translucent matrix. SGM is capable of photocatalysis combined with diffusion of nucleophiles, electrophiles, and salts from pore space. The photocatalytic efficiencies of SGM at various silica contents were quantified in batch reactors using methylene blue destruction over time and cycles. Methylene blue concentrations of 10 mg/L were effectively degraded (>90%) within 40 min. This effectiveness was retained over multiple cycles and various methylene blue concentrations. SGM is a passive and cost-effective granular treatment system technology which can translate to other organic contaminants and industrial processes.

scholarly journals Cobalt Oxide on a Nanoporous TUD-1 Catalyst for Methylene Blue Dye Interaction DFT Studies and Degradation

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1754
Author(s):  
Muthusamy Poomalai Pachamuthu ◽  
Sambath Baskaran ◽  
Chandrakumar Manivannan ◽  
Somasundaram Chandra Kishore ◽  
Stefano Bellucci ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Wastewater Treatment ◽  
Organic Contaminants ◽  
Density Functional ◽  
High Surface ◽  
Partial Density ◽  
Blue Dye ◽  
Spectroscopic Techniques ◽  
Amorphous Sio2 ◽  
Uniform Dispersion

Fenton and Fenton-like advanced oxidation processes (AOP) have been substantially utilized in wastewater treatment for the removal of organic contaminants. The present investigation explores the catalytic activity of cobalt dispersed over nanoporous silicate material (CoO/TUD-1), TUD-1, for the Fenton-type degradation of methylene blue (MB) dye present in wastewater, with hydrogen peroxide (H2O2) as an oxidant. The catalyst, which was prepared using the hydrothermal method, was characterized using analytical and spectroscopic techniques, such as X-ray diffraction (XRD), N2 adsorption–desorption isotherms, UV-visible diffuse reflectance (DR), scanning electron microscope (SEM), transmission electron microscopy (TEM) and Fourier transform infrared (FTIR). The results indicated that the CoO/TUD-1 possessed three-dimensional structures with a high surface area and a pore diameter capable of the uniform dispersion of cobalt species. Density functional theory (DFT) simulations were performed to study the most stable tetra coordinate adsorption configuration of a single Co atom on amorphous SiO2. To understand the geometric and electronic structure of this configuration, electron density differences, Bader charge, and partial density of states were examined. The results obtained from the DFT calculations confirmed the occurrence of electron transfer from the Co atom to the amorphous SiO2. The calculated adsorption energy was found to be -1.58 eV, which indicated that the MB dye was strongly adsorbed by parallel configuration mode and degraded more easily. Further, the addition of a 0.1g/L dose of the prepared CoO /TUD degraded the MB dye effectively (~95%) within 240 min of contact. Thus, CoO/TUD-1 is a potential material for the removal of organic contaminants and the degradation of dyes in wastewater treatment.

scholarly journals Preparation and Application of ZnFe2O4/α-Al2O3 for Photocatalytic Degradation of Methylene Blue Dye and Real Textile Effluent

2019 ◽  
Vol 8 (2) ◽  
pp. 68-75
Author(s):  
Abdulhamid Hamza ◽  
Alhaji Saleh Zanna Umara ◽  
Diya'uddeen Basheer Hasan
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Degradation ◽  
Oxygen Demand ◽  
Textile Wastewater ◽  
Precipitation Method ◽  
Blue Dye ◽  
Methylene Blue Dye ◽  
Al2o3 Support ◽  
Α Al2o3 ◽  
Co Precipitation

Present work was aimed at the development of α-Al2O3 supported ZnFe2O4 visible-light responsive photocatalysts. ZnFe2O4 and α-Al2O3 supported ZnFe2O4 were synthesized using co-precipitation method followed by calcination at 500 °C. The synthesized photocatalysts were characterized using x-ray diffraction (XRD) and scanning electron microscopy (SEM). The synthesized ZnFe2O4 has low crystallinity.  The particle size of ZnFe2O4 is much smaller than that of the α-Al2O3 support, and ZnFe2O4 particles are dispersed on the surface of the crystalline α-Al2O3 support. 30 wt % ZnFe2O4/α-Al2O3 exhibited the highest photocatalytic activity for degradation of methylene blue dye than ZnFe2O4 and other α-Al2O3 supported photocatalysts containing 10 wt%, 20 wt% and 40 wt% ZnFe2O4. Kinetics of photocatalytic degradation of methylene blue dye using 30 wt% ZnFe2O4/Al2O3 obeys Langmuir–Hinshelwood kinetic model. Photocatalytic treatment of real textile wastewater resulted in more effective (when compared to photolytic treatment) in the reduction of wastewater’s chemical oxygen demand (COD), pH, conductivity and total dissolved solids (TDS). 30 wt% ZnFe2O4/Al2O3 was found to be more effective than unsupported ZnFe2O4 for the reduction of wastewater’s COD, pH, conductivity and TDS.

scholarly journals Synthesis of Metal/Silica/Titania Composites for the Photocatalytic Removal of Methylene Blue Dye

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
Sana Ahmad ◽  
Arfa Saeed
Keyword(s):  
Methylene Blue ◽  
Organic Pollutant ◽  
Sol Gel ◽  
Blue Dye ◽  
Methylene Blue Dye ◽  
Reaction Conditions ◽  
Structure Morphology ◽  
Photocatalytic Removal ◽  
Ft Ir ◽  
Metal Doped

The present work deals with the synthesis of the metal-doped titanium dioxide/silica composite by using the sol-gel method. The structure, morphology, and composition of the prepared samples were characterized by using Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The prepared composites were used for the photodegradation of methylene blue dye in sunlight. Different parameters like pH, time, and catalytic concentration were varied to optimize the reaction conditions. Maximum 99.8% degradation was observed with the Ni-doped composite. The results indicate extraordinary efficiency of all metal-doped composites for the removal of the harmful organic pollutant like methylene blue.

Synthesis and Characterization of BaAl2O4 Catalyst and its Photocatalytic Activity Towards Degradation of Methylene Blue Dye

2019 ◽  
Vol 233 (8) ◽  
pp. 1161-1181 ◽  
Author(s):  
Shifa Wang ◽  
Huajing Gao ◽  
Leiming Fang ◽  
Yong Wei ◽  
Yanwu Li ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Gamma Ray ◽  
Energy Gap ◽  
Active Species ◽  
High Photocatalytic Activity ◽  
Blue Dye ◽  
Optical Energy Gap ◽  
Optical Fluorescence ◽  
Flake Structure

Abstract Hexagonal BaAl2O4 catalyst has been prepared using a gamma-ray irradiation assisted polyacrylamide gel method. The catalysts synthesized at different calcining temperatures were analyzed to insight into their effects on the structural, crystalline, surface morphology, color, optical, fluorescence and photocatalytic properties of the hexagonal BaAl2O4 catalyst. Increasing the calcining temperature has obvious influences on the crystallinity, color, optical properties and the formation of the hexagonal BaAl2O4 catalyst. The optical energy gap (Eg) value of the hexagonal BaAl2O4 catalyst increases with the increasing of calcining temperature. TEM image of the pure hexagonal BaAl2O4 catalyst shows a morphology of flake structure and aggregation. Raman spectroscopy of the pure hexagonal BaAl2O4 catalyst exhibits four luminescent background peaks at 400, 415, 428 and 445 nm mainly due to the oxygen vacancies (VO), Ba vacancies (VBa) and some color centers exists in the BaAl2O4 sample. A comparison of photocatalytic activity among samples for degradation of methylene blue (MB) dye indicates that the pure hexagonal BaAl2O4 catalyst exhibits highest photocatalytic activity under the irradiation of both visible and ultraviolet light. Based on the fluorescence experiment, electrochemical and active species tests, the high photocatalytic activity of the pure hexagonal BaAl2O4 catalyst to be related to hole (h+) and hydroxyl radical (⋅OH) and also to the defects in the sample.

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