scholarly journals Rapid Solar-Light Driven Superior Photocatalytic Degradation of Methylene Blue Using MoS2-ZnO Heterostructure Nanorods Photocatalyst

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2254 ◽  
Author(s):  
Ritika ◽  
Manjot Kaur ◽  
Ahmad Umar ◽  
Surinder Mehta ◽  
Surinder Singh ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Performance ◽  
Hexagonal Phase ◽  
Rhombohedral Phase ◽  
Active Species ◽  
Charge Carriers ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Photocatalytic Removal ◽  
Wurtzite Hexagonal Phase

Herein, MoS2-ZnO heterostructure nanorods were hydrothermally synthesized and characterized in detail using several compositional, optical, and morphological techniques. The comprehensive characterizations show that the synthesized MoS2/ZnO heterostructure nanorods were composed of wurtzite hexagonal phase of ZnO and rhombohedral phase of MoS2. The synthesized MoS2/ZnO heterostructure nanorods were used as a potent photocatalyst for the decomposition of methylene blue (MB) dye under natural sunlight. The prepared MoS2/ZnO heterostructure nanorods exhibited ~97% removal of MB in the reaction time of 20 min with the catalyst amount of 0.15 g/L. The kinetic study revealed that the photocatalytic removal of MB was found to be in accordance with pseudo first-order reaction kinetics with an obtained rate constant of 0.16262 min−1. The tremendous photocatalytic performance of MoS2-ZnO heterostructure nanorods could be accredited to an effective charge transportation and inhibition in the recombination of photo-excited charge carriers at an interfacial heterojunction. The contribution of active species towards the decomposition of MB using MoS2-ZnO heterostructure nanorods was confirmed from scavenger study and terephthalic acid fluorescence technique.

Enhanced Photocatalytic Performance of Sn6SiO8 Nanoparticles and Their Reduced Graphene Oxide (rGO) Nanocomposite

2020 ◽  
Vol 20 (9) ◽  
pp. 5426-5432
Author(s):  
G. Gnanamoorthy ◽  
M. Muthukumaran ◽  
P. Varun Prasath ◽  
V. Karthikeyan ◽  
V. Narayanan ◽  
...  
Keyword(s):  
Visible Light ◽  
Photocatalytic Performance ◽  
Separation Efficiency ◽  
Dye Degradation ◽  
Hexagonal Phase ◽  
Active Species ◽  
Organic Chemical ◽  
Light Illumination ◽  
Sem Images ◽  
Radical Trapping

Photocatalysts provide excellent potential for the full removal of organic chemical pollutants as an environmentally friendly technology. It has been noted that under UV-visible light irradiation, nanostructured semiconductor metal oxides photocatalysts can degrade different organic pollutants. The Sn6SiO8/rGO nanocomposite was synthesized by a hydrothermal method. The Sn6SiO8 nanoparticles hexagonal phase was confirmed by XRD and functional groups were analyzed by FT-IR spectroscopy. The bandgap of Sn6SiO8 nanoparticles (NPs) and Sn6SiO8/GO composites were found to be 2.7 eV and 2.5 eV, respectively. SEM images of samples showed that the flakes like morphology. This Sn6SiO8/rGO nanocomposite was testing for photocatalytic dye degradation of MG under visible light illumination and excellent response for the catalysts. The enhancement of photocatalytic performance was mainly attributed to the increased light absorption, charge separation efficiency and specific surface area, proved by UV-vis DRS. Further, the radical trapping experiments revealed that holes (h+) and superoxide radicals (·O−2) were the main active species for the degradation of MG, and a possible photocatalytic mechanism was discussed.

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.

The influence of solution matrix on the photocatalytic removal of color from natural waters

1998 ◽  
Vol 38 (6) ◽  
pp. 155-162 ◽  
Author(s):  
M. Bekbölet ◽  
Z. Boyacioglu ◽  
B. özkaraova
Keyword(s):  
Reaction Kinetics ◽  
Natural Waters ◽  
Removal Rate ◽  
Color Removal ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Phosphate Ions ◽  
Photocatalytic Removal ◽  
Adsorption Data ◽  
Pseudo First Order

Photocatalytic color removal of humic acid was studied in the presence of common inorganic anions; namely, chloride, nitrate, sulfate and phosphate ions at pH 6.8. Color removal rates were explained in terms of pseudo-first order and Langmuir-Hinshelwood kinetics. The Freundlich adsorption data were also evaluated to assess a relationship between the adsorption data and the reaction kinetics. The presence of chloride, nitrate and sulfate ions exhibited different trends when the rate is expressed as pseudo-first order reaction kinetics. In case of Langmuir-Hinshelwood kinetics, the decolorization rates were decreased in the order of the anions as, chloride, nitrate and sulfate. The presence of phosphate ions strongly inhibited the color removal rate.

scholarly journals Design and Operation of a Photocataytic Reactor: A Study of Dye (Methylene Blue) Removal Process

2014 ◽  
Vol 28 (1) ◽  
pp. 41-44
Author(s):  
MA Islam ◽  
M Rakib Uddin ◽  
MSA Amin ◽  
MI Haque ◽  
MSR Molla
Keyword(s):  
Methylene Blue ◽  
Chemical Engineering ◽  
Feed Solution ◽  
Continuous Reactor ◽  
Catalyst Loading ◽  
Pseudo First Order Reaction ◽  
Photocatalytic Reactor ◽  
Initial Concentration ◽  
First Order ◽  
First Results

The degradation of Methylene Blue (MB) in aqueous solution has been investigated in a photocatalytic reactor under UV radiation and in presence of zinc oxide (ZnO). The photodegradation kinetics follows pseudo-first order reaction. The effect of process parameters such as catalyst loading and initial concentration of MB on the degradation is investigated. The results show that the degradation rate is affected insignificantly by the increases in the catalyst dosage. Batch test, however, shows that with an increase in the initial concentration the apparent rate constant gradually decreases. The first results with a continuous reactor with a diluted feed solution show inspiring dye removal. DOI: http://dx.doi.org/10.3329/jce.v28i1.18110 Journal of Chemical Engineering, Vol. 28, No. 1, December 2013: 41-44

scholarly journals BiOCOOH Microflowers Decorated with Ag/Ag2CrO4 Nanoparticles as Highly Efficient Photocatalyst for the Treatment of Toxic Wastewater

Catalysts ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 93 ◽  
Author(s):  
Shijie Li ◽  
Bing Xue ◽  
Jialin Chen ◽  
Wei Jiang ◽  
Yanping Liu
Keyword(s):  
Photocatalytic Performance ◽  
Wide Band ◽  
Active Species ◽  
Charge Carriers ◽  
The Novel ◽  
Wide Band Gap ◽  
Morphological Studies ◽  
Wide Band Gap Semiconductors ◽  
Suppressed Recombination

A novel flower-like Ag/Ag2CrO4/BiOCOOH heterojunction photocatalyst was synthesized by a facile in-situ precipitation strategy combined with photoreduction treatment. Morphological studies revealed that numerous Ag/Ag2CrO4 nanoparticles were evenly anchored on BiOCOOH microflowers, producing a novel heterojunction with the compactly interfacial contact. Optical absorption characterization demonstrated that Ag/Ag2CrO4/BiOCOOH possessed much better sunlight harvesting ability than Ag2CrO4/BiOCOOH and BiOCOOH. Photocatalytic experiments verified that compared with BiOCOOH, Ag2CrO4, Ag/Ag2CrO4, and Ag2CrO4/BiOCOOH, Ag/Ag2CrO4/BiOCOOH achieved remarkable efficiency by eliminating 100% of rhodamine B (RhB), 82.6% of methyl orange (MO) or 69.4% of ciprofloxacin (CIP) within 50 min at a catalyst dosage of 0.4 g/L. The high photocatalytic performance is likely owing to the improved sunlight response and the distinctly suppressed recombination of charge carriers arising from the formation of the novel 3D hierarchical heterostructure. The quenching test signified that h+, and •O2− were detected as the prevailing active species in wastewater treatment. This study may provide a viable strategy for enhancing the photocatalytic performance of wide band-gap semiconductors.

scholarly journals Facile Synthesis of Bi2MoO6 Microspheres Decorated by CdS Nanoparticles with Efficient Photocatalytic Removal of Levfloxacin Antibiotic

Catalysts ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 477 ◽  
Author(s):  
Shijie Li ◽  
Yanping Liu ◽  
Yunqian Long ◽  
Liuye Mo ◽  
Huiqiu Zhang ◽  
...  
Keyword(s):  
Light Absorption ◽  
Photocatalytic Performance ◽  
High Efficiency ◽  
Charge Carriers ◽  
Cds Nanoparticles ◽  
Efficient Removal ◽  
Photocatalytic Removal ◽  
Visible Light Driven ◽  
Calcination Method ◽  
Huge Challenge

Developing high-efficiency and stable visible-light-driven (VLD) photocatalysts for removal of toxic antibiotics is still a huge challenge at present. Herein, a novel CdS/Bi2MoO6 heterojunction with CdS nanoparticles decorated Bi2MoO6 microspheres has been obtained by a simple solvothermal-precipitation-calcination method. 1.0CdS/Bi2MoO6 has stronger light absorption ability and highest photocatalytic activity with levofloxacin (LEV) degradation efficiency improving 6.2 or 12.6 times compared to pristine CdS or Bi2MoO6. CdS/Bi2MoO6 is very stable during cycling tests, and no appreciable activity decline and microstructural changes are observed. Results signify that the introduction of CdS could enhance the light absorption ability and dramatically boost the separation of charge carriers, leading to the excellent photocatalytic performance of the heterojunction. This work demonstrates that flower-like CdS/ Bi2MoO6 is an excellent photocatalyst for the efficient removal of the LEV antibiotic.

Photocatalytic degradation of ofloxacin by ZnO/CsxWO3 composite synthesized by two-step method: A kinetic study

2019 ◽  
Vol 12 (05) ◽  
pp. 1950068 ◽  
Author(s):  
Wenwen Ning ◽  
Zhihuan Zhao ◽  
Honghong Chang ◽  
Zhanyong Gu ◽  
Bing Zhang ◽  
...  
Keyword(s):  
Degradation Rate ◽  
Photocatalytic Performance ◽  
Solvothermal Method ◽  
Active Species ◽  
Step Method ◽  
Full Spectrum ◽  
First Order ◽  
First Order Kinetics ◽  
Photogenerated Electrons ◽  
Prepared Composite

The composite of ZnO/CsxWO3 with heterojunction was prepared by a two-step solvothermal method and the degradation of ofloxacin solution under full-spectrum light irradiation was carried out to evaluate the performance. The composites were characterized by XRD, SEM, EDS and UV-Vis-NIR reflectance. The result shows that the prepared composite has an ideal optical absorption in the spectral region of 200–2500[Formula: see text]nm and higher photocatalytic performance compared with ZnO and CsxWO3. Moreover, [Formula: see text], [Formula: see text]OH and [Formula: see text][Formula: see text] radicals are determined to be the active species. It is suggested that the heterojunction between ZnO and CsxWO3 for ZnO/CsxWO3 composite is important for improving the charge separation and thus restraining the recombination of photogenerated electrons and holes. Photodegradation of ofloxacin catalyzed by ZnO/CsxWO3 followed the first-order kinetics and the degradation rate of ZnO/2CsxWO3 was about two times higher than those of CsxWO3 and ZnO.

scholarly journals ZnCDs/ZnO@ZIF-8 Zeolite Composites for the Photocatalytic Degradation of Tetracycline

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 934
Author(s):  
Yong Cheng ◽  
Xiuxiu Wang ◽  
Yu Mei ◽  
Dan Wang ◽  
Changchun Ji
Keyword(s):  
Catalytic Activity ◽  
Photocatalytic Degradation ◽  
Photocatalytic Performance ◽  
Active Species ◽  
Degradation Efficiency ◽  
Experimental Result ◽  
Porous Nanostructure ◽  
Resultant Material

Considering the photocatalytic performance of CDs, ZnO, and the unique porous nanostructure and stability of ZIF-8, we prepared ZnCDs/ZnO@ZIF-8 zeolite composites. The resultant material represented an enhanced ability for the photodegradation of TC compared with that of ZnCDs and ZnO. The photocatalytic degradation efficiency reached over 85%. The catalytic activity of the composites was maintained after four cycles. The experimental result indicated that ×O2 radical was the active species in the reaction.

scholarly journals Oxidative degradation of gentamicin present in water by an electro-Fenton process and biodegradability improvement

2019 ◽  
Vol 17 (1) ◽  
pp. 1017-1025
Author(s):  
Mohamed Réda Arhoutane ◽  
Muna Shueai Yahya ◽  
Miloud El Karbane ◽  
Kacem El Kacemi
Keyword(s):  
Chemical Oxygen Demand ◽  
Biological Process ◽  
Oxidative Degradation ◽  
Oxygen Demand ◽  
Polluted Water ◽  
Applied Current ◽  
Pseudo First Order Reaction ◽  
First Order ◽  
Appropriate Treatment ◽  
By Products

AbstractIn the context of environmental protection, where there is a need to develop effective operations for carrying out appropriate treatment of polluted water by pharmaceuticals. Therefore, the present study aims at evaluating the degradation for gentamicin through electro-Fenton (EF) operation, through taking into consideration the effect of several parameters of experimental in the process, namely, the concentration of initial gentamicin, the applied current and the Fe+2 (II) quantities. The (EF) operation employed involves a carbon-felt as cathode and platinum as anode at pH 3. Studies for the gentamicin kinetics is monitored by HPLC giving a pseudo-first order reaction following by a chemical oxygen demand, with a reached degree of mineralization 96% after of four hours of treatment through current 100 mA/cm2 with 0.1 mM of Fe+2. We find that the degradation for molecule of gentamicin is accompanied by an augmentation of the biodegradability, assesse through the Biochemical Oxygen Demand (BOD5) on chemical oxygen demand (COD) ratio, that augmentation from 0 to 0.41 before treatment after 30 min for EF treatment, showing that there is potential for conjugation of the EF process and the biological process. Furthermore, the by-products have been identified on the basis of HPLC-MS/MS results.

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