Photocatalytic degradation of dye pollutants in the presence of acetone

2001 ◽  
Vol 44 (6) ◽  
pp. 173-180 ◽  
Author(s):  
S.-M. Tsui ◽  
W. Chu
Keyword(s):  
Quantum Yield ◽  
Critical Factor ◽  
Reactive Dye ◽  
Optimum Conditions ◽  
Decay Kinetics ◽  
Triplet Energy ◽  
First Order ◽  
Dye Pollutants ◽  
Initial Ph ◽  
Reactive Red 2

The photodegradation of textile azo dyes in aqueous solution containing acetone (ACE) photosensitizer was investigated at 253.7 nm. In this study, a typical azo reactive dye (C I Reactive Red 2 - RR2) is used as the probe compound. ACE is a powerful photosensitizer that possesses high triplet energy, and the presence of ACE significantly enhances the overall photodegradation reaction through simultaneous sensitization. In the UV/ACE system, at the optimum conditions, over 97% of RR2 can be successfully decomposed and decolored within 300 seconds of retention time. The photodegradation mechanisms of RR2 involve both photodechlorination and photoreduction, which follow pseudo first-order decay kinetics. The quantum yield of the photolysis system has been evaluated as a function of ACE concentration and the initial pH. RR2 contains the chlorotriazinyl group, which undergoes hydrolysis and results in the formation of hydrochloric acid, indicating that the photodechlorination process is the dominant reaction mechanism. The photo-product, H+, is likely to retard the quantum yield of dye decay, suggesting that the initial pH is a critical factor in changing the photodecolorization rates of dye. Generally, this system is more favorable at higher pH levels.

scholarly journals Degradation of Methyl Violet over Fenton-Like Hydroxyapatite Catalysts, Kinetics and Thermodynamics Studies

2021 ◽  
Author(s):  
Yasmina Roumila ◽  
Djaafar Meziani ◽  
Saadia Debaghi ◽  
Kaïssa Abdmeziem
Keyword(s):  
Dye Degradation ◽  
Methyl Violet ◽  
Active Species ◽  
Precipitation Method ◽  
Maximum Efficiency ◽  
Fenton Process ◽  
Optimal Conditions ◽  
Optimum Conditions ◽  
First Order ◽  
Initial Ph

Abstract Hydroxyapatite (HA), a calcium hydroxyphosphate was prepared via precipitation method and used as a catalyst in a Fenton like process for methyl violet (MV) dye degradation. This study is aimed to evaluate the effect of hydrogen peroxide concentration, HA dose, initial pH, temperature and MV concentration on the catalyst performance to find out the optimum conditions leading to maximum efficiency of the Fenton process. The results showed that MV dye with a concentration of 20 mg L-1 can be removed within just 10 minutes at the optimal conditions of 36 mmol L–1 H2O2 and 2.5 g L–1 HA at pH of 6.65 and T = 48 °C). The experimental outcome of this study also demonstrates that HA displayed a good recyclability over three cycles; while the use of scavenger highlighted that the hydroxyl radical HO• was the main active species for MV degradation. The catalytic tests result of MV dye degradation were analyzed by the first-order, second-order and Benhnajady-Modirshahla-Ghanbery (BMG) kinetic models, those showing that the Fenton like reaction follows the first-order and BMG models. The activation energy of the reaction and the values of thermodynamic parameters such as standard enthalpy (ΔH*0), entropy (ΔS*0) and Gibbs free energy (ΔG*0) were also evaluated. Those results revealed that the degradation of MV over the as-synthesized material is an endothermic and non-spontaneous process.

scholarly journals Pyrite/H2O2/hydroxylamine system for efficient decolorization of rhodamine B

2021 ◽  
Author(s):  
Guang-Jun He ◽  
Deng-Jie Zhong ◽  
Yun-Lan Xu ◽  
Peng Liu ◽  
Si-Jing Zeng ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Rhodamine B ◽  
Textile Wastewater ◽  
Oh Radical ◽  
Pyrite Surface ◽  
Optimum Conditions ◽  
Dye Pollutants ◽  
Initial Ph ◽  
Degradation Reaction ◽  
Textile Wastewater Treatment

Abstract To improve the efficiency of the Fe(II)/Fe(III) cycle and continuous reactivity of pyrite, a pyrite/H2O2/hydroxylamine (HA) system was proposed to treat rhodamine B (RhB). The results showed that near-complete decolorization and 52.8% mineralization 50 mg L−1 RhB were achieved under its optimum conditions: HA 0.8 mM, H2O2 1.6 mM, pyrite 0.4 g L−1, and initial pH 4.0. The degradation reaction was dominated by an •OH radical produced by the reaction of Fe2+ with H2O2 in solution. HA primarily had two roles: in solution, HA could accelerate the Fe(II)/Fe(III) cycle through its strong reducibility to enhance RhB decolorization; on the pyrite surface, HA could improve the continuous reactivity of pyrite by inhibiting the oxidation of pyrite. In addition, the dosing manner of HA had a significant effect on RhB decolorization. In addition, the high decolorization and mineralization efficiency of other dye pollutants suggested that the pyrite/H2O2/HA system might be widely used in textile wastewater treatment.

Degradation of chlorpyriphos in water by advanced oxidation processes

2010 ◽  
Vol 10 (1) ◽  
pp. 1-6 ◽  
Author(s):  
R. Murillo ◽  
J. Sarasa ◽  
M. Lanao ◽  
J. L. Ovelleiro
Keyword(s):  
Reaction Time ◽  
Light Source ◽  
Advanced Oxidation Processes ◽  
Advanced Oxidation ◽  
The Other ◽  
Molar Ratio ◽  
Optimum Conditions ◽  
Oxidation Processes ◽  
Other Hand ◽  
Initial Ph

The degradation of chlorpyriphos by different advanced oxidation processes such as photo-Fenton, TiO2, TiO2/H2O2, O3 and O3/H2O2 was investigated. The photo-Fenton and TiO2 processes were optimized using a solar chamber as light source. The optimum dosages of the photo-Fenton treatment were: [H2O2]=0.01 M; [Fe3 + ]=10 mg l−1; initial pH = 3.5. With these optimum conditions total degradation was observed after 15 minutes of reaction time. The application of sunlight was also efficient as total degradation was achieved after 60 minutes. The optimum dosage using only TiO2 as catalyst was 1,000 mg l−1, obtaining the maximum degradation at 20 minutes of reaction time. On the other hand, the addition of 0.02 M of H2O2 to a lower dosage of TiO2 (10 mg l−1) provides the same degradation. The ozonation treatment achieved complete degradation at 30 minutes of reaction time. On the other hand, it was observed that the degradation was faster by adding H2O2 (H2O2/O3 molar ratio = 0.5). In this case, total degradation was observed after 20 minutes.

Screening and Desilication of a Silicate Bacteria

2011 ◽  
Vol 236-238 ◽  
pp. 253-257
Author(s):  
Xian Zhen Zhang ◽  
De Si Sun ◽  
Hai Lin
Keyword(s):  
Particle Size ◽  
Incubation Time ◽  
Ph Value ◽  
Solution Temperature ◽  
Optimum Conditions ◽  
Initial Ph ◽  
Silicate Bacteria ◽  
Bauxite Ore

The strain Jgj-1 was isolated from Gaoan bauxite ore. The relations of desilication of the strain Jgj-1 and the pH of solution, temperature, shaking speed, incubation time, particle size were investigated. The results shows the optimum conditions of bioleaching are as following: at 28°C, initial pH value is 7.2, particle size 0.056mm, 200rpm shaking speed, incubation 5-7 days.

Decolorization of Reactive Black 5 using Peroxymonosulfate in Fentonlike Process

2013 ◽  
Vol 16 (2) ◽  
Author(s):  
Gülin Ersöz ◽  
Süheyda Atalay
Keyword(s):  
Advanced Oxidation Processes ◽  
Catalytic Effect ◽  
Industrial Effluents ◽  
Operating Parameters ◽  
Reactive Black 5 ◽  
Process Performance ◽  
Optimum Conditions ◽  
Oxidation Processes ◽  
Wide Availability ◽  
Initial Ph

AbstractOne of the advanced oxidation processes, the Oxone process, was studied to determine its effects on the decolorization of Reactive Black 5 (RB5) in an aqueous solution. Ferrous ion was chosen as the transition metal due to its potential catalytic effect and wide availability in dye containing industrial effluents. The effects of the operating parameters such as Fe(II) and Oxone concentration, initial pH, and temperature on the process performance were investigated. The optimum conditions were determined as: 0.5 mM of Oxone concentration, 0.5 mM of Fe

scholarly journals Biogas Production from Combined Irish Potato and Poultry Wastes: Optimization and Kinetic Studies

2018 ◽  
Vol 7 (3.36) ◽  
pp. 170
Author(s):  
Umar M. Ibrahim ◽  
Saeed I. Ahmed ◽  
Babagana Gutti ◽  
Idris M. Muhammad ◽  
Usman D. Hamza ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Kinetic Parameters ◽  
Ph Value ◽  
Biogas Production ◽  
Irish Potato ◽  
Coefficient Of Determination ◽  
Optimum Conditions ◽  
Biogas Yield ◽  
Potato Waste ◽  
Initial Ph

The combination of Irish potato waste (IPW) and poultry waste (PW) can form a synergy resulting into an effective substrate for a better biogas production due to some materials they contain. In this work, optimization and kinetic study of biogas production from anaerobic digestion of IPW and PW was investigated. Response surface methodology (RSM) was applied to optimize conditions such as initial pH, solids concentrations and waste ratios. The anaerobic digestion of the two wastes was carried out in the mesophilic condition and Box-Behnken design (BBD) was used to develop and analyze a predictive model which describes the biogas yield. The results revealed that there is a good fit between the experimental and the predicted biogas yield as revealed by the coefficient of determination (R2) value of 97.93%. Optimization using quadratic RSM predicts biogas yield of 19.75% at the optimal conditions of initial pH value 7.28, solids concentration (w/v) 9.85% and waste ratio (IPW:PW) 45:55%. The reaction was observed to have followed a first order kinetics having R2 and relative squared error (RSE) values of 90.61 and 9.63% respectively. Kinetic parameters, such as rate constant and half-life of the biogas yield were evaluated at optimum conditions to be 0.0392 day-1 and 17.68 days respectively. The optimum conditions and kinetic parameters generated from this research can be used to design real bio-digesters, monitor substrate concentrations, simulate biochemical processes and predict performance of bio-digesters using IPW and PW as substrate.  

Cobalt Ion Extraction from Wastewater by P204 Microemulsion Saponified

2012 ◽  
Vol 496 ◽  
pp. 407-410
Author(s):  
Du Shu Huang ◽  
Jin Gang Yu ◽  
Rui Min Xiao ◽  
Zi Jing Li ◽  
Li Da Sun
Keyword(s):  
Organic Phase ◽  
Volume Ratio ◽  
Extraction Process ◽  
Microemulsion System ◽  
Optimum Conditions ◽  
Extraction Coefficient ◽  
Initial Concentration ◽  
Ion Extraction ◽  
Initial Ph ◽  
Cobalt And Nickel

The extraction process of cobalt using microemulsion system saponified with P204 as extracting agent was studied. The influence of initial concentration, the concentration of P204, initial pH, the extracting time and the concentration of cobalt and nickel on extraction coefficient were also studied. Experimental results show that the saponification microemulsion system using P204 as extractant is thermodynamic stable, and it can separate cobalt better. The optimum conditions were achieved as: the initial concentration is 0.05 mol/L, pH is 2; The concentration of P204 is 10%, extraction time is 10 min; The volume ratio of organic phase to water phase is 2:1.

Improvement of delta-endotoxin production from local Bacillus thuringiensis Se13 using Taguchi’s orthogonal array methodology

2018 ◽  
Vol 43 (6) ◽  
pp. 662-670 ◽  
Author(s):  
Ardahan Eski ◽  
Zihni Demirbağ ◽  
İsmail Demir
Keyword(s):  
Bacillus Thuringiensis ◽  
Incubation Period ◽  
Orthogonal Array ◽  
Incubation Temperature ◽  
Taguchi Methods ◽  
Optimum Level ◽  
Optimum Conditions ◽  
Delta Endotoxin ◽  
Initial Ph ◽  
Four Levels

Abstract Objective The insecticidal activity of Bacillus thuringiensis directly depends on the yield of delta-endotoxins. In this study, various nutritional and cultural parameters influencing delta-endotoxin synthesis by a local isolate of B. thuringiensis Se13 were investigated using Taguchi methods. Methods In the first experiment, four factors, incubation period, incubation temperature, initial pH and medium, each at four levels, were selected and an orthogonal array layout of L16 was carried out. In the second experiment, Taguchi’s orthogonal array method of L27 was used to evaluate the effects of the different concentration of medium components. Taguchi’s signal–noise ratio and variance analysis were applied to determine the effect of the factors. After each experiment, verification studies were carried out using determined optimum conditions. Results The optimum conditions for incubation period, incubation temperature, initial pH, and medium determined as 72 h, 30°C, pH 9, and M4 medium, respectively. In the second experiment, soybean flour (5%), glucose (5%), KH2PO4 (0.3%), K2HPO4 (0.1%), MgSO4 (0.4%) were determined as the optimum conditions. The delta-endotoxin yield was elevated to 1559.25 μg mL−1 when the factors were adjusted to optimum level. Conclusion Optimization using the Taguchi method appeared to be a good choice for the overproduction of delta-endotoxin.

Photocatalytic Efficiency for Dye Decolorization of the UV/TiO2, UV/TiO2 + In2O3 and UV/TiO2-In2O3 Systems

2013 ◽  
Vol 831 ◽  
pp. 263-266
Author(s):  
Chung Hsin Wu ◽  
Chao Yin Kuo ◽  
Chih Hao Lai ◽  
Wei Yang Chung
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sol Gel ◽  
Dye Decolorization ◽  
X Ray Diffraction ◽  
First Order ◽  
First Order Kinetics ◽  
Vis Spectroscopy ◽  
Reactive Red 2

This study explored the decolorization of C.I. Reactive Red 2 (RR2) by the ultraviolet (UV)/TiO2, UV/TiO2 + In2O3, and UV/TiO2-In2O3 systems. The TiO2-In2O3 was generated by the sol-gel method and TiO2 + In2O3 was created by mixing TiO2 and In2O3 powders. The surface properties of TiO2, In2O3, and TiO2-In2O3 were analyzed by X-ray diffraction, a specific surface area analyzer, UV-vis spectroscopy, and scanning electron microscopy. The specific surface area of TiO2, In2O3, and TiO2-In2O3 was 29.5, 44.6, and 35.7 m2/g, respectively; additionally, the band gap of TiO2, In2O3, and TiO2-In2O3 was 2.95, 2.64, and 2.91 eV; respectively. The decolorization rate constant fit pseudo-first-order kinetics and that of the UV/TiO2, UV/TiO2 + In2O3, and UV/TiO2-In2O3 systems was 0.0023, 0.0031, and 0.0072 min-1; respectively.

The Production of Vitamin B6 by Microorganisms in Corn Meal1

1989 ◽  
Vol 52 (11) ◽  
pp. 827-828
Author(s):  
KITIMAL VAJARANANT ◽  
MARION L. FIELDS
Keyword(s):  
Bacillus Licheniformis ◽  
Vitamin B6 ◽  
Ph Effect ◽  
Lactobacillus Brevis ◽  
Corn Meal ◽  
Optimal Temperature ◽  
Optimum Conditions ◽  
Streptococcus Faecalis ◽  
Initial Ph

Five microorganisms out of 22 cultures previously isolated from fermenting corn meal produced vitamin B6. These included Hansenula subpelliculosa (strain 1), Moraxella sp. (strain 4), and Bacillus licheniformis (strains 6, 9, and 10). Microorganisms not producing vitamin B6 were: Streptococcus faecalis (strains 3, 8, 25, and 34); Lactobacillus brevis (strains 11, 12, 14, 15, 16, 3, 38, 41, 43, 44, and 45); Agrobacter spp. (strains 22 and 23). B. licheniformis strains 6 and 10 were studied further to establish optimum conditions for vitamin B6 production in corn meal. For strain 6, optimal initial pH and temperature were 7 and 45°C, respectively. For B. licheniformis strain 10, there was no initial pH effect and the optimal temperature was also 45°C.

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