scholarly journals Photocatalytic Degradation of a Systemic Herbicide: Picloram from Aqueous Solution Using Titanium Oxide (TiO2) under Sunlight

2020 ◽  
Vol 4 (4) ◽  
pp. 58
Author(s):  
Md. Rakibul Islam ◽  
Jahida Binte Islam ◽  
Mai Furukawa ◽  
Ikki Tateishi ◽  
Hideyuki Katsumata ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
Titanium Oxide ◽  
Irradiation Time ◽  
Degradation Mechanism ◽  
Chloride Ion ◽  
Reaction Rate Constant ◽  
Ammonium Ion ◽  
Light Reaction ◽  
First Order Kinetics ◽  
Initial Ph

The photocatalytic degradation of picloram (4-amino-3,5,6-trichloro-2-pyridincarboxylic acid), which is one of popular acidic herbicide, was investigated with the existence of titanium oxide (TiO2) under sunlight. The total photocatalytic degradation of 20 ppm of picloram was occurred within 30 min irradiation with TiO2, while a negligible degradation was found without TiO2 under sunlight. The influence of various parameters, like TiO2 dosage, solution initial pH, intensity of light, reaction temperature and irradiation time, was found during the photocatalytic degradation of picloram. The mineralization of picloram was proved by the deterioration of total organic carbon (TOC) of the photocatalytic process. The pseudo–first order kinetics of photocatalytic degradation was obtained according to the Langmuir–Hinshelwood model, and the reaction rate constant was 17.6 × 10−2 min−1. Chloride ion, ammonium ion, nitrate ion and CO2 were erected as the final products after completing the photocatalytic degradation of picloram. The intermediate products could not be determined by the GC–MS during the degradation of picloram. Therefore, the degradation mechanism of the picloram was proposed based on the frontier electron density and the point charge at each atom of the picloram molecule. The photocatalytic degradation method, using sunlight, may develop into as a pragmatic technique to purify picloram contaminated wastewater.

scholarly journals Enhanced Photocatalytic Degradation and Mineralization of Furfural Using UVC/TiO2/GAC Composite in Aqueous Solution

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Bahram Ghasemi ◽  
Bagher Anvaripour ◽  
Sahand Jorfi ◽  
Neematollah Jaafarzadeh
Keyword(s):  
Photocatalytic Degradation ◽  
Removal Efficiency ◽  
Irradiation Time ◽  
Titanium Dioxide Nanoparticles ◽  
Sol Gel ◽  
Total Pore Volume ◽  
Operational Parameters ◽  
Experimental Conditions ◽  
First Order Kinetics ◽  
Initial Ph

Titanium dioxide nanoparticles were immobilized on granular activated carbon (GAC) as a porous and low-density support for photocatalytic degradation of furfural. The TiO2/GAC composite was synthetized using the simple sol-gel method and fully characterized. The effects of the operational parameters of furfural concentration (200–700 mg/L), initial pH (2–12), TiO2/GAC composite dosage (1–3.5 g/L), and irradiation time (20–120 min) were studied. The synthetized TiO2/GAC composite exhibited a total pore volume of 0.13 cm3/g and specific surface area of 35.91 m2/g. Removal efficiency of up to 95% was observed at initial pH of 10, TiO2/GAC dosage of 2.5 g/L, irradiation time of 80 min, and initial furfural concentration of 500 mg/L. The photocatalyst could be reused at least four consecutive times with a mere 2% decrease in furfural removal efficiency. Mineralization efficiency of 94% was obtained within 80 min. Pseudo-first-order kinetics best fit the photocatalytic degradation of furfural under experimental conditions.

scholarly journals Electro-photocatalytic degradation of amoxicillin using calcium titanate

2018 ◽  
Vol 16 (1) ◽  
pp. 949-955 ◽  
Author(s):  
Lvshan Zhou ◽  
Xiaogang Guo ◽  
Chuan Lai ◽  
Wei Wang
Keyword(s):  
Photocatalytic Degradation ◽  
Reaction Rate ◽  
Irradiation Time ◽  
Oxygen Demand ◽  
Reaction Rate Constant ◽  
Calcium Titanate ◽  
Experimental Conditions ◽  
Exponential Factor ◽  
First Order ◽  
First Order Kinetics

AbstractThe electro-photocatalytic degradation of amoxicillin in aqueous solution was investigated using single factor test by the potassium permanganate method for measuring the values of chemical oxygen demand (CODMn). Batch experiments were carried out successfully under different conditions, including initial amoxicillin concentration, calcium titanate dosage, pH, UV irradiation time, electrolyte and temperature. The experimental results show that there is a great difference between electro-photocatalytic and photocatalitic degradation. The maximum electro-photocatalytic degradation efficiency can increase to 79% under the experimental conditions of 200 mL amoxicillin solution (100 mg L-1) with 0.5 g calcium titanate by pH=3 for 120 min irradiation and 0.058 g sodium chloride as electrolyte at 318.5K. In addition, the reaction rate constant of 0.00848~0.01349 min-1, activation energy of 9.8934 kJ mol-1 and the pre-exponential factor of 0.5728 were obtained based on kinetics studies, indicating that the electro-photocatalytic reaction approximately followed the first-order kinetics model.

Photocatalytic Degradation of 2,4,5–TCP in TiO2/UV/H2O2 System

2012 ◽  
Vol 518-523 ◽  
pp. 2649-2652
Author(s):  
Yan Ping Zong ◽  
Xian Hua Liu ◽  
Xi Wen Du ◽  
Yi Ren Lu ◽  
Xiao Xuan Shi
Keyword(s):  
Hydrogen Peroxide ◽  
Photocatalytic Degradation ◽  
Absorption Spectroscopy ◽  
Degradation Mechanism ◽  
Analysis Method ◽  
Photocatalytic System ◽  
Initial Ph ◽  
Effects Of Ph

The photocatalytic degradation of 2,4,5–Trichlorophenol(2,4,5–TCP) in TiO2/UV/ H2O2 photocatalytic system was examined using absorption spectroscopy and GC-MS. It was found that 2,4,5–TCP could be degraded almost completely within 100 min under the conditions of initial pH 3, C(H2O2) = 0.08 mol/L and C(TiO2) = 0.5 g/L. The effects of pH and the concentration of hydrogen peroxide on the degradation of 2,4,5–TCP were also studied. Besides, the degradation mechanism was concluded accorrding to convertional analysis method too.

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.

scholarly journals Photocatalytic Degradation of Bismarck Brown G Using Irradiated ZnO in Aqueous Solutions

2010 ◽  
Vol 7 (2) ◽  
pp. 540-544 ◽  
Author(s):  
Falah H. Hussein ◽  
Ahmed F. Halbus ◽  
Hussein A. K. Hassan ◽  
Wisam A. K. Hussein
Keyword(s):  
Zinc Oxide ◽  
Aqueous Solutions ◽  
Photocatalytic Degradation ◽  
Irradiation Time ◽  
Degradation Process ◽  
First Order ◽  
Photocatalytic Decolorization ◽  
First Order Kinetics ◽  
Decolorization Efficiency ◽  
Increasing Temperature

In this study, a homemade photoreactor equipped with 125w/542 high pressure mercury lamp as a source for near-UV radiation, was used for photocatalytic degradation of aqueous solutions of Bismarck brown G, (C18H20N8Cl2),4-[5-(2,4-Diamino-5-methylphenyl)diazenyl-2-methylphenyl] diazenyl -6-methylbenzol-1,3-diamin using zinc oxide. The disappearance of the original colored reactant concentrations with irradiation time was monitored spectrophotometrically by comparison with unexposed controls. It is noticed that the photocatalytic degradation process was high at the beginning and then decreased with time following pseudo first-order kinetics according to the Langmuir–Hinshelwood model. The effects of zinc oxide mass, dye concentration and temperature on photocatalytic decolorization efficiency (P.D.E.) were studied. P.D.E. reached 95.76% for Bismarck brown G after 50 minutes of irradiation at 293.15 K P.D.E. was found to increase with increasing temperature and the activation energy of photocatalytic degradation was calculated and found to be equal to 32±1 kJ mol-1.

Degradation of Orange IV Dye Solution Catalyzed by PVDF/Fe3+-TiO2 Catalytic Membrane in the Presence of H2O2

2010 ◽  
Vol 150-151 ◽  
pp. 1705-1709
Author(s):  
Ying Jie Zhang ◽  
Li Zhang ◽  
Xiao Fei Ma ◽  
Li Li ◽  
Jun Ma
Keyword(s):  
Reaction Rate ◽  
Removal Rate ◽  
Sol Gel ◽  
Reaction Rate Constant ◽  
Catalytic Membrane ◽  
Electron Hole ◽  
Membrane Area ◽  
First Order Kinetics ◽  
Initial Ph ◽  
Ph Range

A new heterogeneous PVDF/Fe3+-TiO2 catalytic membrane is prepared by sol-gel method, which had a well catalytic activity to decompose H2O2. The effect of initial pH, e initial concentration of H2O2 and Orange IV, temperature, and membrane area on the reaction rate is discussed. The PVDF/Fe3+-TiO2 catalytic membrane can effectively decolorize Orange IV in the pH range of 3.0-5.0. The optimal concentration of H2O2 is 15mmol/L. The reaction rate constant is proportional to the initial concentrations of Orange IV. The higher the temperature, the faster the reaction rate is, this reaction follows pseudo-first-order kinetics with activation energy of 1.54kJ/mol. Reuse of catalyst did not decrease the removal rate of Orange IV. The experiments of t-butanol, EDTA and XPS measurement showed that •OH, the electron hole and the ferryl are all the reactive species in the degradation of Orange IV.

scholarly journals Photocatalytic Degradation of Aniline Using TiO2Nanoparticles in a Vertical Circulating Photocatalytic Reactor

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
F. Shahrezaei ◽  
Y. Mansouri ◽  
A. A. L. Zinatizadeh ◽  
A. Akhbari
Keyword(s):  
Photocatalytic Degradation ◽  
Catalyst Concentration ◽  
Irradiation Time ◽  
Effect Of Temperature ◽  
Photo Degradation ◽  
Photocatalytic Reactor ◽  
Operational Conditions ◽  
Uv Illumination ◽  
Petroleum Refinery Wastewater ◽  
Initial Ph

Photocatalytic degradation of aniline in the presence of titanium dioxide (TiO2) and ultraviolet (UV) illumination was performed in a vertical circulating photocatalytic reactor. The effects of catalyst concentration (0–80 mg/L), initial pH (2–12), temperature (293–323 K), and irradiation time (0–120 min) on aniline photodegradation were investigated in order to obtain the optimum operational conditions. The results reveal that the aniline degradation efficiency can be effectively improved by increasing pH from 2 to 12 and temperature from 313 to 323 K. Besides, the effect of temperature on aniline photo degradation was found to be unremarkable in the range of 293–313 K. The optimum catalyst concentration was about 60 mg/L. The Langmuir Hinshelwood kinetic model could successfully elucidate the effects of the catalyst concentration, pH, and temperature on the rate of heterogeneous photooxidation of aniline. The data obtained by applying the Langmuir Hinshelwood treatment are consistent with the available kinetic parameters. The activated energy for the photocatalytic degradation of aniline is 20.337 kj/mol. The possibility of the reactor use in the treatment of a real petroleum refinery wastewater was also investigated. The results of the experiments indicated that it can therefore be potentially applied for the treatment of wastewater contaminated by different organic pollutants.

scholarly journals Simultaneous synthesis-immobilization of nano ZnO on perlite for photocatalytic degradation of an azo dye in semi batch packed bed photoreactor

2012 ◽  
Vol 14 (4) ◽  
pp. 69-76 ◽  
Author(s):  
Ali Khani ◽  
Mahmoud Reza Sohrabi
Keyword(s):  
Photocatalytic Degradation ◽  
Packed Bed ◽  
Acid Orange 7 ◽  
Operational Parameters ◽  
Kinetic Rate Constant ◽  
Nano Zno ◽  
First Order Kinetics ◽  
Initial Ph ◽  
On Line ◽  
Simultaneous Synthesis

Abstract A novel, simple and simultaneous synthesis-immobilization of nano ZnO on perlite (nZnO-P) as a photocatalyst for photocatalytic degradation of Acid orange 7 (AO7) in aqueous solution was investigated. The effect of operational parameters such as initial dye concentration, initial pH, flow rate, photocatalyst granule size, temperature and the kinetic of the removal of AO7 in terms of the Langmuir-Hinshelwood model in a designed semi batch packed bed photoreactor connected to an on-line sampling UV-Vis spectrophotometer was studied. The results showed that AO7 removal efficiency increased with nZnO-P using the designed setup and the proposed photocatalyst was more efficient than TiO2 as a standard catalyst. Our results confirmed the pseudo-first-order kinetics model. The values of the adsorption equilibrium constant, KAO7, the kinetic rate constant of surface reaction, kc, and the activation energy (Ea) were found to be 0.57 (mg.l−1)−1, 0.41 mg.l−1.min−1 and 11.44 kJ/mol, respectively.

Study of Photocatalytic Degradation Mechanism of Butyl Enzyl Phthalate Ester

2011 ◽  
Vol 374-377 ◽  
pp. 1017-1020
Author(s):  
Yan Lu ◽  
Li Ming Xi
Keyword(s):  
Ultraviolet Radiation ◽  
Photocatalytic Degradation ◽  
Degradation Mechanism ◽  
Degradation Process ◽  
Phthalate Ester ◽  
Initial Ph ◽  
New Material ◽  
Photocatalytic Degradation Mechanism

Under ultraviolet radiation, the photocatalytic degradation mechanism of Butyl enzyl phthalate ester (BBP) was studied with TiO2as the catalyst. As a result, BBP could be degraded efficiently, and the efficiency was 85% after 6h degradation. During the degradation process, the acidity of the degradation system changed obviously. The initial pH of the solution was 6.0, and it increased to 6.23 after 15min degradation, however it decreased to 3.89 after 6h degradation. Some photodegradation intermediates in the different photocatalytic steps were examined and analyzed by means of GC-MS. For the BBP, the photocatalytic degradation firstly reacted on the benzyloxy chain, and new material occured by the recomposition of the educts in the degradation.

Coupled reduction of chlorinated hydrocarbons and heavy metals by zerovalent silicon

2004 ◽  
Vol 50 (8) ◽  
pp. 89-96 ◽  
Author(s):  
R.-A. Doong ◽  
C.-C. Lee ◽  
K.-T. Chen ◽  
S.-F. Wu
Keyword(s):  
Heavy Metals ◽  
Ph Value ◽  
Degradation Mechanism ◽  
Chlorinated Hydrocarbons ◽  
Degradation Pathway ◽  
Reaction Rate Constant ◽  
Contaminated Sites ◽  
Divalent Metal Ions ◽  
First Order Kinetics ◽  
Removal Of Heavy Metals

The feasibility of using zerovalent silicon (Si0) as a novel reductant to remove chlorinated ompounds and heavy metals in contaminated sites was investigated. The kinetics and degradation mechanism of carbon tetrachloride (CT) by Si0 were also examined. Results showed that zerovalent silicon could effectively dechlorinate the chlorinated compounds. A nearly complete dechlorination of CT by Si0 was obtained within 14 h. The produced concentrations of chloroform (CF) accounted for 71-88% loss of CT, showing that reductive dechlorination is the major degradation pathway for the degradation of chlorinated hydrocarbons by Si0. The degradation followed pseudo first-order kinetics and the normalized surface reaction rate constant (ksa) for CT dechlorination ranged between 0.0342 and 0.0454 L m-2 h-1 when CT concentrations were in the range of 3-20 μM. A linear relationship between the ksa and pH value was also established. In addition, zerovalent silicon has a high capability in the removal of heavy metals. 83% of Cr(VI) was removed by 0.5g Si0 within 5 h, which is higher than that by Fe0. The removal efficiency of divalent metal ions by Si0 followed the order of Cu(II) > Pb(II) > Ni(II). This indicates that zerovalent silicon is an alternative reductant and can undergo coupled reduction of heavy metals and chlorinated hydrocarbons in contaminated groundwater.

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