scholarly journals Ag2O and NiO Decorated CuFe2O4 with Enhanced Photocatalytic Performance to Improve the Degradation Efficiency of Methylene Blue

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4760
Author(s):  
Lu Liu ◽  
Nan Hu ◽  
Yonglei An ◽  
Xingyuan Du ◽  
Xiao Zhang ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Rate Constant ◽  
Fenton Reaction ◽  
Degradation Rate ◽  
Photocatalytic Performance ◽  
Reaction System ◽  
Dye Wastewater ◽  
Degradation Rate Constant ◽  
Degradation Effect ◽  
High Degradation Rate

Dye wastewater is a serious threat to human health and life. It is an important task for researchers to treat it efficiently. Among many treatment methods, the photo-Fenton method can rapidly degrade organic pollutants. In this study, a ternary photocatalyst, Ag2O-NiO/CuFe2O4, was prepared and applied for a photo-Fenton reaction to degrade methylene blue (MB). MB had the best degradation effect when 10 mg of the catalyst were used in an 80 mL reaction system for measurement. The degradation rate of MB was up to 96.67% in 60 min with a high degradation rate constant k=5.67×10−2min−1. The total organic carbon (TOC) degradation rate was 78.64% with a TOC degradation rate constant of k=2.57×10−2min−1. Therefore, this study fully proves that Ag2O-NiO/CuFe2O4 can catalyze the photo-Fenton reaction and effectively degrade MB.

Sensitivity analysis using a diffuse pollution hydrologic model to assess factors affecting pesticide concentrations in river water

2010 ◽  
Vol 62 (11) ◽  
pp. 2579-2589 ◽  
Author(s):  
Koji Tani ◽  
Yoshihiko Matsui ◽  
Kentaro Narita ◽  
Koichi Ohno ◽  
Taku Matsushita
Keyword(s):  
Sensitivity Analysis ◽  
River Water ◽  
Rate Constant ◽  
Degradation Rate ◽  
Hydrologic Model ◽  
Adsorption Coefficient ◽  
Pesticide Concentration ◽  
Artificial Drainage ◽  
Degradation Rate Constant ◽  
Intermittent Irrigation

We quantitatively evaluated the factors that affect the concentrations of rice-farming pesticides (an herbicide and a fungicide) in river water by a sensitivity analysis using a diffuse pollution hydrologic model. Pesticide degradation and adsorption in paddy soil affected concentrations of the herbicide pretilachlor but did not affect concentrations of the fungicide isoprothiolane. We attributed this difference to the timing of pesticide application in relation to irrigation and drainage of the rice paddy fields. The herbicide was applied more than a month before water drainage of the fields and runoff was gradual over a long period of time, whereas the fungicide was applied shortly before drainage and runoff was rapid. However, the effects of degradability-in-water on the herbicide and fungicide concentrations were similar, with concentrations decreasing only when the rate constant of degradation in water was large. We also evaluated the effects of intermittent irrigation methods (irrigation/artificial drainage or irrigation/percolation) on pesticide concentrations in river water. The runoff of the fungicide, which is applied near or in the period of intermittent irrigation, notably decreased when the method of irrigation/artificial drainage was changed to irrigation/percolation. In a sensitivity analysis evaluating the synergy effect of degradation and adsorbability in soil, the degradation rate constant in soil greatly affected pesticide concentration when the adsorption coefficient was small but did not affect pesticide concentration when the adsorption coefficient was large. The pesticide concentration in the river water substantially decreased when either or both the degradation rate constant in soil and adsorption coefficient was large.

Research on the Photocatalytic Degradability of Methylene Blue Solution by Photocatalysis Bamboo Charcoal Fiber Knitted Fabric

2011 ◽  
Vol 332-334 ◽  
pp. 1040-1044 ◽  
Author(s):  
Qiu Mei Wang ◽  
Lei Tan ◽  
Rong Wen Zhou ◽  
Zhi Wei Zou ◽  
Xue Mei Xu
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Degradation ◽  
Degradation Rate ◽  
Liquid Level ◽  
Knitted Fabric ◽  
Bamboo Charcoal ◽  
Methylene Blue Solution ◽  
Initial Concentration ◽  
Blue Solution ◽  
Degradation Effect

In this paper, the photocatalytic degradation of methylene blue solution by photocatalysis bamboo charcoal fiber knitted fabric was studied. The relationships were analyzed between the photocatalytic degradation rate and the reaction time, the initial concentration, pH of methylene blue solution, and the distance between the UV light centre and liquid level. The results indicates that there is an remarkable photocatalytic degradation effect of methylene blue solution by photocatalysis bamboo charcoal fiber knitted fabric under UV-irradiation, even the degradation rate could reach to 67.02%. The degradation effect was better with lower initial concentration of methylene blue solution, higher initial pH，and the shorter distance between light centre and liquid level.

scholarly journals pH effect on stability and kinetics degradation of nitazoxanide in solution

2020 ◽  
Vol 4 (1) ◽  
pp. 12-17
Author(s):  
Fábio Barbosa ◽  
Leonardo Pezzi ◽  
Julia Sorrentino ◽  
Martin Steppe ◽  
Nadia Volpato ◽  
...  
Keyword(s):  
Rate Constant ◽  
Degradation Product ◽  
Degradation Rate ◽  
Degradation Kinetics ◽  
Ph Effect ◽  
Degradation Rate Constant ◽  
Main Degradation Product ◽  
Wide Ph Range ◽  
The Stability ◽  
Ph Range

Stability studies correspond to a set of tests designed to assess changes in the quality of a given drug over time and under the influence of a number of factors. Among these factors, pH plays an important role, due to the catalytic effect that hydronium and hydroxide ions can play in several reactions. In the present study, the degradation kinetics of nitazoxanide was evaluated over a wide pH range, and the main degradation product generated was identified by LC-MS/MS. Nitazoxanide showed first-order degradation kinetics in the pH range of 0.01 to 10.0 showing greater stability between pH 1.0 and 4.0. The degradation rate constant calculated for these pH was 0.0885 x 10-2 min-1 and 0.0689 x 10-2 min-1, respectively. The highest degradation rate constant value was observed at pH 10.0 (0.7418 x 10-2 min-1) followed by pH 0.01 (0.5882 x 10-2 min-1). A major degradation product (DP-1) was observed in all conditions tested. Through LC-MS/MS analysis, DP-1 was identified as a product of nitazoxanide deacetylation. The effect of pH on the stability of nitazoxanide and the kinetic data obtained contribute to a better understanding of the intrinsic stability characteristics of nitazoxanide.

scholarly journals The Composite of ZrO2-TiO2 Produced from Local Zircon Sand Used as A Photocatalyst for The Degradation of Methylene Blue in A Single Batik Dye Wastewater

2016 ◽  
Vol 11 (2) ◽  
pp. 133 ◽  
Author(s):  
Ita Permadani ◽  
Dhini A. Phasa ◽  
Andini W. Pratiwi ◽  
Fitria Rahmawati
Keyword(s):  
Waste Water ◽  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Rate Constant ◽  
Weight Ratio ◽  
Reaction Engineering ◽  
Kinetics Study ◽  
Dye Wastewater ◽  
Heat Treated ◽  
Zircon Sand

<p>In this research, a composite of ZrO<sub>2</sub>-TiO<sub>2</sub> was used as a photocatalyst in the degradation of dye wastewater. The dye waste water is a single Methylene Blue, MB, wastewater from Batik industry. Meanwhile, the ZrO<sub>2</sub> was prepared from zircon sand founded from Bangka Island, Indonesia. The composite was prepared at various weight ratio and heat treated at 500 <sup>o</sup>C. The result shows that the purity of ZrO<sub>2</sub> from zircon sand is only 66.46 %. However, the addition of ZrO<sub>2</sub> into TiO<sub>2</sub> able to increase the photocatalytic activity proven by 88.75 % degradation of MB at a ZrO<sub>2</sub>-TiO<sub>2</sub> weight ratio of 1:1. The result is higher than the degradation with anatase TiO<sub>2</sub>; that is only 62.67 %. The kinetics study found that the photocatalytic degradation of MB with single TiO<sub>2</sub> has the rate constant of 1.85x10<sup>-2</sup> minutes<sup>-1</sup>. Meanwhile, the rate constant of the MB degradation with the composite ZrO<sub>2</sub>-TiO<sub>2</sub> is 16.73x10<sup>-2</sup> minutes<sup>-1</sup>. Copyright © 2016 BCREC GROUP. All rights reserved</p><p><em>Received: 20<sup>th</sup> August 2015; Revised: 13<sup>rd</sup> December 2015; Accepted: 30<sup>th</sup> December 2015</em></p><p><strong>How to Cite:</strong> Permadani, I., Phasa, D.A., Pratiwi, A.W., Rahmawati, F. (2016). The Composite of ZrO<sub>2</sub>-TiO<sub>2</sub> Produced from Local Zircon Sand Used as A Photocatalyst for The Degradation of Methylene Blue in A Single Batik Dye Wastewater. <em>Bulletin of Chemical Reaction Engineering &amp; Catalysis</em>, 11 (2): 133-139. (doi:10.9767/bcrec.11.2.539.133-139)</p><p> <strong>Permalink/DOI</strong>: http://dx.doi.org/10.9767/bcrec.11.2.539.133-139</p>

Modified graphene quantum dots-zinc oxide nanocomposites for photocatalytic degradation of organic dyes and commercial herbicide

2019 ◽  
Vol 39 (3-4) ◽  
pp. 81-94 ◽  
Author(s):  
Suchada Phophayu ◽  
Pichitchai Pimpang ◽  
Sawitree Wongrerkdee ◽  
Supphadate Sujinnapram ◽  
Sutthipoj Wongrerkdee
Keyword(s):  
Quantum Dots ◽  
Photocatalytic Degradation ◽  
Rate Constant ◽  
Degradation Rate ◽  
Carrier Lifetime ◽  
Organic Dyes ◽  
Graphene Quantum Dots ◽  
High Crystallinity ◽  
Degradation Rate Constant ◽  
Photocatalytic Material

The high crystallinity of graphene quantum dots-ZnO nanocomposites is considered to have a significant effect in improving the carrier lifetime for enhanced photocatalytic degradation. The graphene quantum dots-ZnO nanocomposites were synthesized by adding graphene quantum dots solution into starting precursors during the precipitation. Characterization was performed using various techniques. High crystallinity of graphene quantum dots-ZnO nanocomposites is obtained in terms of increased crystal size and decreased dislocation density. The improved crystallinity increases the carrier lifetime on the material surface for the functional improvement of photocatalytic material. Photocatalytic test of methylene blue and methyl orange was performed under UV irradiation. Degradation rate constant reaches the maximum value for both organic dyes for the appropriate preparing condition of graphene quantum dots-ZnO nanocomposites. The graphene quantum dots-ZnO nanocomposites were then applied to degrade commercial glyphosate herbicide contaminants for an agricultural wastewater treatment investigation. The investigation aims to demonstrate a facile useful way of herbicide contaminant reduction for the better health of farmers. The graphene quantum dots-ZnO nanocomposites show an enhancement of the photocatalytic process with improved degradation rate constant (23% increased) in comparison to pure ZnO. Therefore, this work demonstrates that graphene quantum dots-ZnO nanocomposites can be used as a photocatalytic material for degrading organic dyes and commercial herbicide contaminants owing to its low-cost and environmental-friendly properties.

Intensification of a Pond System by Fibrous Carriers

1993 ◽  
Vol 28 (7) ◽  
pp. 117-123 ◽  
Author(s):  
Qi Peishi ◽  
Wang Boazhen ◽  
Ma Fang ◽  
Zhang Jinsong ◽  
Li Tingjun
Keyword(s):  
Mathematical Model ◽  
Microbial Communities ◽  
Flow Pattern ◽  
Rate Constant ◽  
Degradation Rate ◽  
Heilongjiang Province ◽  
Conventional System ◽  
Mixed Flow ◽  
Pond System ◽  
Degradation Rate Constant

A study was carried out on the intensification of a pond system, consisting of an anaerobic pond, a facultative pond and a polishing pond, in Anda City, Heilongjiang Province, by fibrous carriers packed in the anaerobic pond, by means of which the performance of the pond system was remarkably improved with higher removal capacities and efficiencies for SS, BOD5, COD, TN, TP and bacteria, compared with the conventional system. The mechanism for the intensified effect was found to be ascribed to the increase of biomass in the form of biofilm attached to the surface of the fibrous carriers and more even distribution of the biomass in the pond. A mathematical model based on the complete mixed flow pattern was developed both for the intensified and conventional anaerobic pond, and the organic degradation rate constant value K in the former was found to be much greater than that in the latter. The microbial communities in both the ponds were also observed.

scholarly journals Enhanced Photocatalytic Performance of NiO-Decorated ZnO Nanowhiskers for Methylene Blue Degradation

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
I. Abdul Rahman ◽  
M. T. M. Ayob ◽  
S. Radiman
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Uv Irradiation ◽  
Degradation Rate ◽  
Photocatalytic Performance ◽  
Nio Nanoparticles ◽  
Methylene Blue Degradation ◽  
Maximal Peak ◽  
P Type

ZnO nanowhiskers were used for photodecomposition of methylene blue in aqueous solution under UV irradiation. The rate of methylene blue degradation increased linearly with time of UV irradiation. 54% of degradation rate was observed when the ZnO nanowhiskers were used as photocatalysts for methylene blue degradation for 80 min under UV irradiation. The decoration of p-type NiO nanoparticles on n-type ZnO nanowhiskers significantly enhanced photocatalytic activity and reached 72% degradation rate of methylene blue by using the same method. NiO-decorated ZnO was recycled for second test and shows 66% degradation from maximal peak of methylene blue within the same period. The increment of photocatalytic activity of NiO-decorated ZnO nanowhiskers was explained by the extension of the electron depletion layer due to the formation of nanoscale p-n junctions between p-type NiO and n-type ZnO. Hence, these products provide new alternative proficient photocatalysts for wastewater treatment.

Impact of transverse and longitudinal dispersion on first-order degradation rate constant estimation

2004 ◽  
Vol 73 (1-4) ◽  
pp. 3-14 ◽  
Author(s):  
Greg A. Stenback ◽  
Say Kee Ong ◽  
Shane W. Rogers ◽  
Bruce H. Kjartanson
Keyword(s):  
Rate Constant ◽  
Degradation Rate ◽  
Longitudinal Dispersion ◽  
First Order ◽  
Degradation Rate Constant

scholarly journals PENGARUH INTENSITAS CAHAYA TERHADAP DEGRADASI WARNA AGARAGAR YANG DIWARNAI SARI UMBI BIT MERAH (Beta vulgaris L. var. rubra L.)

Agric ◽  
2016 ◽  
Vol 25 (1) ◽  
pp. 42
Author(s):  
Lydia Ninan Lestario ◽  
Noviana Gunawan ◽  
Yohanes Martono
Keyword(s):  
Light Intensity ◽  
Beta Vulgaris ◽  
Rate Constant ◽  
Degradation Rate ◽  
Color Stability ◽  
Fluorescent Light ◽  
Beetroot Juice ◽  
Constant Rate ◽  
Degradation Rate Constant ◽  
Color Degradation

<p>The aims of this research were to determine the concentration of beetroot juice in jelly which panelists like best; to determine the color degradation rate constant in jelly colored with beetroot juice caused by sunlight and fluorescent light; and color degradation rate constant of jelly colored with synthetic colorant.</p><p>The organoleptic test used 2,5 percent; 5 percent; 7,5 percent; 10 percent; and 12,5 percent beetroot juice and permitted synthetic colorant for food. The light intensity to test the beetroot color stability in jelly were 879,06 lux, 1.688,54 lux, 2.342,2 lux and 6.752,2 lux.</p><p>The results showed that the concentration of beetroot juice which panelists like best was 5 percent.; The color degradation rate constant of jelly colored by 5 percent beetroot juice on intensity 879,06 lux was 0,0468 hour-1; 1.688,54 lux was 0,0565 hour-1; 2.342,2 lux was 0,0653 hour-1;<br />6.752,2 lux was 0,0887 hour-1. The higher the light intensity, the higher the degradation constant rate.</p>

Study on Preparation of a New-Type Catalyst and its Catalytic Activity

2014 ◽  
Vol 955-959 ◽  
pp. 2705-2708
Author(s):  
Qin Fang Lu ◽  
Tao Yang
Keyword(s):  
Methylene Blue ◽  
Catalytic Activity ◽  
Visible Light ◽  
Degradation Rate ◽  
Catalyst Activity ◽  
Utilization Rate ◽  
Dye Wastewater ◽  
Calcination Time ◽  
New Type

To improve the utilization rate of visible light in the degradation of the dye wastewater, the supported mesoporous TiO2 catalyst with perlite as the carrier was prepared. The effect of the calcination time and the loading time on the degradation of the methylene blue by the catalyst was analyzed. The result showed that: as the calcination time exceeded 1.5h, the catalyst activity decreased with the calcination time increasing; under the condition of the optimal calcination time of 1.5h, the degradation rate of methylene blue by visible light reached 71.59%; the multi-loading was in favor of increasing the catalyst activity, of which 3-time loading was the optimal.

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