scholarly journals Degradation and mineralization of violet-3B dye using C-N-codoped TiO2 photocatalyst

2019 ◽  
Vol 25 (4) ◽  
pp. 529-535 ◽  
Author(s):  
Reza Audina Putri ◽  
Safni Safni ◽  
Novesar Jamarun ◽  
Upita Septiani ◽  
Moon-Kyung Kim ◽  
...  
Keyword(s):  
Reaction Rate ◽  
Sol Gel ◽  
Organic Dye ◽  
Halogen Lamp ◽  
Acidic Ph ◽  
Initial Concentration ◽  
First Order ◽  
First Order Kinetics ◽  
Pseudo First Order ◽  
Catalyst Dosage

The present study investigated the photodegradation of synthetic organic dye; violet-3B, without and with the addition of C-N-codoped TiO<sub>2</sub> catalyst using a visible halogen-lamp as a light source. The catalyst was synthesized by using a peroxo sol-gel method with free-organic solvent. The effects of initial dye concentration, catalyst dosage, and pH solution on the photodegradation of violet-3B were examined. The efficiency of the photodegradation process for violet-3B dye was higher at neutral to less acidic pH. The kinetics reaction rate of photodegradation of violet-3B dye with the addition of C-N-codoped TiO<sub>2</sub> followed pseudo-first order kinetics represented by the Langmuir-Hinshelwood model, and increasing the initial concentration of dyes decreased rate constants of photodegradation. Photodegradation of 5 mg L<sup>-1</sup> violet-3B dye achieved 96% color removal within 240 min of irradiation in the presence of C-N-codoped TiO<sub>2</sub> catalyst, and approximately 44% TOC was removed as a result of the mineralization.

New insights on the UV/TiO2 photocatalytic treatment of thiomersal and its 2-sulfobenzoic acid product

2021 ◽  
Vol 02 ◽  
Author(s):  
Emmanuel M. de la Fournière ◽  
Jorge M. Meichtry ◽  
Graciela S. Custo ◽  
Eduardo A. Gautier ◽  
Marta I. Litter
Keyword(s):  
Degradation Products ◽  
Acidic Ph ◽  
Cosmetic Products ◽  
Acid Product ◽  
First Order ◽  
First Order Kinetics ◽  
Photocatalytic Destruction ◽  
Pseudo First Order ◽  
Mineralization Degree ◽  
Suitable Technique

Background: Thiomersal (TM), a complex between 2-mercaptobenzoic acid (2-MBA) and ethylmercury (C2H5Hg+), is an antimicrobial preservative used in immunological, ophthalmic, cosmetic products, and vaccines. Objective: TM has been treated by UV/TiO2 photocatalysis in the presence or absence of oxygen at acidic pH. C2H5Hg+, 2-MBA, and 2-sulfobenzoic acid (2-SBA) were found as products. A 2-SBA photocatalytic treatment was undertaken to study sulfur evolution. Methods: Photocatalytic runs were performed using a UVA lamp (λmax = 352 nm), open to the air or under N2. A suspension of the corresponding TM or 2-SBA salt and TiO2 was prepared, and pH was adjusted. Suspensions were stirred in the dark for 30 min and then irradiated. TM, 2-MBA, 2-SBA, and C2H5Hg+ were quantified by HPLC, sulfur by TXRF, and the deposits on the photocatalyst were analyzed by chemical reactions. The mineralization degree was followed by TOC. Sulfate was determined using BaCl2 at 580 nm. Results: Photocatalytic destruction of TM and total C2H5Hg+ was complete under N2 and air, but TM degradation was much faster in air. The evolution of TM and the products followed a pseudo-first-order kinetics. Conclusion: TiO2-photocatalytic degradation is a suitable technique for the treatment of TM and its degradation products. In contrast to other organomercurial compounds, TM degradation is faster in the presence of O2, indicating that the oxidative mechanism is the preferred pathway. A significant TM mineralization (> 60%, NPOC and total S) was obtained. TM was more easily degraded than 2-SBA. Sulfate was the final product.

Enhancement of decomposition of 2-chlorophenol with ultrasound/H2O2 process

1996 ◽  
Vol 34 (9) ◽  
pp. 41-48 ◽  
Author(s):  
Jih-Gaw Lin ◽  
Cheng-Nan Chang ◽  
Jer-Ren Wu ◽  
Ying-Shih Ma
Keyword(s):  
Ionic Strength ◽  
Reaction Rate ◽  
Order Reaction ◽  
Pseudo First Order Reaction ◽  
Initial Concentration ◽  
First Order ◽  
Toc Removal ◽  
Cp Decomposition ◽  
Effects Of Ph ◽  
Pseudo First Order

We investigated the effects of pH, ionic strength, catalyst, and initial concentration on both decomposition of 2-chlorophenol (2-cp) and removal of total organic carbon (TOC) in aqueous solution with ultrasonic amplitude 120 μm and H2O2 (200 mg/l). When the initial concentrations of 2-cp was 100 mg/l and the pH was controlled at 3, the rate of 2-cp decomposition was enhanced up to 6.6-fold and TOC removal up to 9.8-fold over pH controlled at 11. At pH 3, the efficiency of decomposition of 2-cp was 99% but the removal of TOC was only 63%; a similar situation applied at pH 7 and 11. Hence intermediate compounds were produced and 2-cp was not completely mineralized. When the concentration of ionic strength was increased from 0.001 to 0.1 M, the rate of 2-cp decomposition was enhanced only 0.3-fold, whereas the TOC removal was not enhanced. In comparison of the effects of pH and ionic strength, pH had greater influence on both 2-cp decomposition and TOC removal than ionic strength. The effect of a catalyst (FeSO4) on decomposition of 2-cp was insignificant comparing with direct addition of H2O2. The reaction rate at a smaller initial concentration of 2-cp (10 mg/l) was more rapid than at a greater one (100 mg/l). The rate of 2-cp decomposition and TOC removal appeared to follow pseudo-first-order reaction kinetics.

Solid Super Acid of S2O82- /FexOy-CuOx Catalytic Degradation of Orange IV

2011 ◽  
Vol 239-242 ◽  
pp. 182-185 ◽  
Author(s):  
Ying Jie Zhang ◽  
Guo Rui Liu ◽  
Da Peng Li ◽  
Yue Xiao Tian ◽  
Li Zhang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Heterogeneous Fenton ◽  
First Order ◽  
First Order Kinetics ◽  
Initial Ph ◽  
Good Catalytic Activity ◽  
Super Acid ◽  
Pseudo First Order

Solid super acid (S2O82-/FexOy-CuOx) was prepared and used as a heterogeneous Fenton-like catalyst to decompose H2O2for the degradation of refractory dye Orange IV in water. The factors that affected the degradation of Orange IV were discussed in this heterogeneous Fenton-like system. The catalytic activity of S2O82-/FexOy-CuOxwas evaluated by the degradation of Orange IV and the decomposition of H2O2. The results show that the catalyst S2O82-/FexOy-CuOxhas a good catalytic activity. The reaction follows pseudo-first-order kinetics; the reaction rate constant has a good relationship with the concentration of H2O2. The degradation rate of Orange IV and the decomposition rate of H2O2increase with the increase of temperature and the dosage of catalyst whereas it decreases with the increase of the initial concentration of Orange IV and the initial pH.

Photodegradation of organic matter in fresh garbage leachate using immobilized nano-sized TiO2 as catalysts

2013 ◽  
Vol 69 (6) ◽  
pp. 1219-1226
Author(s):  
C. Chen ◽  
Q. Xie ◽  
B. Q. Hu ◽  
X. L. Zhao
Keyword(s):  
Organic Matter ◽  
Activated Carbon ◽  
Degradation Rate ◽  
Sol Gel ◽  
Oxygen Demand ◽  
Solution Ph ◽  
First Order ◽  
First Order Kinetics ◽  
Catalyst Dosage ◽  
H2o2 Addition

Two immobilized nano-sized TiO2 catalysts, TiO2/activated carbon (TiO2/AC) and TiO2/silica gel (SG) (TiO2/SG), were prepared by the sol–gel method, and their use in the photocatalytic degradation of organic matter in fresh garbage leachate under UV irradiation was investigated. The influences of the catalyst dosage, the initial solution pH, H2O2 addition and the reuse of the catalysts were evaluated. The degradation of organic matter was assessed based on the decrease of the chemical oxygen demand (COD) in the leachate. The results indicated that the degradation of the COD obeyed first-order kinetics in the presence of both photocatalysts. The degradation rate of COD was found to increase with increasing catalyst dosage up to 9 g/L for TiO2/AC and 6 g/L for TiO2/SG, above which the degradation began to attenuate. Furthermore, the degradation rate first increased and then decreased as the solution pH increased from 2 to 14, and the degradation rate increased as the amount of H2O2 increased to 2.93 mM, after which it remained constant. No obvious decrease in the rate of COD degradation was observed during the first four repeated uses of the photocatalysts, indicating that the catalysts could be recovered and reused. Compared with TiO2/AC, TiO2/SG exhibited higher efficiency in photocatalyzing the degradation of COD in garbage leachate.

scholarly journals Photocatalytic Degradation of Erythrosin-B using Cadmium Cobaltite for Water Reuse: Efficiency and Degradation Pathway

2020 ◽  
Vol 32 (9) ◽  
pp. 2143-2148
Author(s):  
JAYANTI SAMOTA ◽  
SURAJ SHARMA ◽  
SHIPRA BHARDWAJ ◽  
KUMUD INTODIA
Keyword(s):  
Photocatalytic Degradation ◽  
Water Reuse ◽  
Reaction Rate ◽  
Degradation Pathway ◽  
Photochemical Degradation ◽  
Erythrosin B ◽  
First Order ◽  
First Order Kinetics ◽  
Pseudo First Order ◽  
The Impact

In present work, a photocatalytic degradation of Erythrosin-B has been studied using cadmium cobaltite. The impact of different parameters such as pH, amount of cadmium cobaltite, concentration of Erythrosin-B and light intensity have been observed on the reaction rate. Radical quenching experiments revealed that hydroxyl radicals are primarily responsible for the degradation of Erythrosin-B. The progress of reaction monitored spectrophotometrically and it followed pseudo first-order kinetics. An experimental mechanism is proposed for the photochemical degradation of Erythrosin-B.

scholarly journals Photocatalytic removal of cefazolin from aqueous solution by AC prepared from mango seed+ZnO under UV irradiation

2018 ◽  
Vol 20 (2) ◽  
pp. 399-407 ◽  
Keyword(s):  
Activated Carbon ◽  
Kinetic Model ◽  
Uv Irradiation ◽  
Advanced Oxidation ◽  
Beam Radiation ◽  
Initial Concentration ◽  
First Order ◽  
First Order Kinetics ◽  
Pseudo First Order ◽  
Mango Seed

Presence of antibiotics in the environment specially in aqueous environments is considered a major warning about health and environment. Thus, this study aims the efficiency of coupled process of Activated Carbon (AC) prepared from mango seed+ZnO under UV irradiation as an advanced oxidation process in removing cefazolin antibiotic from aqueous solutions. This experimental study was carried out in a discontinuous reaction chamber with volume of one liter. In this process, the effect of initial pH parameters of the environment (3– 9), initial concentration of cefazolin (20 – 200 mg/L), concentration of modified, photocatalyzer (20 – 100 mg/L) and reaction time (10 – 60 min) were studied. The pilot used consisted of a low pressure mercury lamp with a 55-watt beam radiation power inside the steel chamber. The kinetic of the process was studied based on pseudo first order kinetics. Results showed that the highest removal efficiency of cefazolin antibiotics in the reaction of UV/AC + ZnO, at optimal conditions of pH= 3, contact time of 60 min, initial concentration of 100 mg/L and modified photocatalyzer of 0.1 g/L was equal to 96%. The kinetic model determined for the process followed kinetic model of pseudo- first order kinetics with high correlation of (R2 = 0.99). Results of present study revealed that photocatalyzer process of nanoparticles oxidation on synthetic activated carbon can be effectively used as an advanced oxidation reaction to remove cefazolin and similar pollutants.

Enzymatic Nitrate Assay by a Kinetic Method Employing Escherichia coli Nitrate Reductase

1985 ◽  
Vol 40 (1-2) ◽  
pp. 134-137 ◽  
Author(s):  
Johannes Schild ◽  
Jobst-Heinrich Klemme
Keyword(s):  
Nitrate Reductase ◽  
Reaction Rate ◽  
Kinetic Method ◽  
Test System ◽  
Enzymatic Assay ◽  
E Coli ◽  
First Order ◽  
First Order Kinetics ◽  
Membrane Bound ◽  
Pseudo First Order

Abstract An enzymatic assay system for nitrate employing the membrane-bound nitrate reductase (EC 1.7.99.4) of E. coli is described. Contrary to previous enzymatic assay systems, the present method is a kinetic one, i.e. the substrate, nitrate, is assayed by measuring the reaction rate of the nitrate reductase-catalyzed reaction. Based on the observation that the nitrate reductase-catalyzed reaction obeys pseudo-first order kinetics, a test system is described allowing the assay of nitrate at a concentration as low as 1 ppm. The relatively high M ichaelis-M enten constant for nitrate (0.3 mᴍ) of the E. coli nitrate reductase favours nitrate assay by the kinetic method.

scholarly journals Photocatalytic degradation of caffeine in a slurry reactor with intermittent UV irradiation: optimization and response surface modelling

2021 ◽  
Author(s):  
C. Nirmala Rani
Keyword(s):  
Photocatalytic Degradation ◽  
Response Surface ◽  
Oxygen Demand ◽  
Surface Modelling ◽  
Initial Concentration ◽  
Design Expert ◽  
First Order ◽  
First Order Kinetics ◽  
Response Surface Modelling ◽  
Catalyst Dosage

Abstract This study focusses on the photocatalytic degradation of caffeine (CAF) a stimulating drug and environmental contaminant that pose threat to humans and the environment. The effect of operating parameters such as; CAF initial concentration (5–20 mg/L), catalyst dosage (0.1–0.9 g/L) and pH (3.0–9.0) were explored in detail. The experimental results showed the maximum CAF and chemical oxygen demand (COD) removals of 87.2% and 66.7% respectively. The optimized parameters were; CAF initial concentration – 5 mg/L, catalyst dosage – 0.5 g/L and pH – 7.2. The photocatalytic degradation of CAF followed pseudo-first order kinetics. The obtained experimental data were analysed with response surface methodology (RSM) using Design Expert Software.

scholarly journals Photodegradation of Sulfadiazine in Aqueous Solution and the Affecting Factors

2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
Xuesen Bian ◽  
Jibing Zhang
Keyword(s):  
Hydroxyl Radicals ◽  
Reaction Rate ◽  
Uv Light ◽  
Degradation Process ◽  
Acidic Ph ◽  
Affecting Factors ◽  
First Order ◽  
First Order Kinetics ◽  
Photodegradation Rate ◽  
Uv Lamp

Knowledge about photochemical behavior of sulfonamides under UV light is limited. In this study, photodegradation of sulfadiazine in water by ultraviolet (UV) light was studied using a 300 W, 365 nm UV lamp. The degradation process followed well the first-order kinetics, with a half-life of 9.76 min in water with air saturation. The photodegradation was slower at acidic pH 4.52 than at pH 6.98 and pH 8.90. Addition of H2O2and nitrate enhanced the photodegradation rate, while addition of ethanol, nitrite, sulfate, and bicarbonate depressed the reaction rate. This study suggested that sulfadiazine photodegradation under UV light is generally favored by the attack of hydroxyl radicals.

Photo-catalytic degradation of gaseous pollutants in paper mills of southern China

TAPPI Journal ◽  
2018 ◽  
Vol 17 (03) ◽  
pp. 167-178 ◽  
Author(s):  
Xin Tong ◽  
Jiao Li ◽  
Jun Ma ◽  
Xiaoquan Chen ◽  
Wenhao Shen
Keyword(s):  
Degradation Rate ◽  
Southern China ◽  
Catalytic Degradation ◽  
Pulp And Paper ◽  
Gaseous Pollutants ◽  
Pulp And Paper Mills ◽  
Paper Mills ◽  
Initial Concentration ◽  
First Order ◽  
First Order Kinetics

Studies were undertaken to evaluate gaseous pollutants in workplace air within pulp and paper mills and to consider the effectiveness of photo-catalytic treatment of this air. Ambient air at 30 sampling sites in five pulp and paper mills of southern China were sampled and analyzed. The results revealed that formaldehyde and various benzene-based molecules were the main gaseous pollutants at these five mills. A photo-catalytic reactor system with titanium dioxide (TiO2) was developed and evaluated for degradation of formaldehyde, benzene and their mixtures. The experimental results demonstrated that both formaldehyde and benzene in their pure forms could be completely photo-catalytic degraded, though the degradation of benzene was much more difficult than that for formaldehyde. Study of the photo-catalytic degradation kinetics revealed that the degradation rate of formaldehyde increased with initial concentration fitting a first-order kinetics reaction. In contrast, the degradation rate of benzene had no relationship with initial concentration and degradation did not conform to first-order kinetics. The photo-catalytic degradation of formaldehyde-benzene mixtures indicated that formaldehyde behaved differently than when treated in its pure form. The degradation time was two times longer and the kinetics did not reflect a first-order reaction. The degradation of benzene was similar in both pure form and when mixed with formaldehyde.

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