Photocatalytic degradation of explosives contaminated water

2002 ◽  
Vol 46 (11-12) ◽  
pp. 139-145 ◽  
Author(s):  
S.-J. Lee ◽  
H.-S. Son ◽  
H.-K. Lee ◽  
K.-D. Zoh
Keyword(s):  
Photocatalytic Degradation ◽  
Total Nitrogen ◽  
Contaminated Water ◽  
Ammonium Ions ◽  
Nitrate Ion ◽  
Photocatalytic Reactor ◽  
Initial Concentration ◽  
Initial Ph ◽  
Alkaline Conditions ◽  
The Impact

This study was undertaken to examine the degradation of TNT, RDX and HMX in a circular photocatalytic reactor with TiO2 as a photocatalyst. We examined the impact of parameters such as the initial concentration, initial pH of solution on rates of photocatalized transformation, and the mineralization. The results showed that photocatalysis is an effective process for the degradation of TNT, RDX and HMX. They could be completely degraded in 150 min with 1.0 g/L TiO2 at pH 7. An increase in the photocatalytic degradation of HMX was noticed with decreasing initial HMX. The rates of RDX and HMX degradation were greater in neutral pH than in acidic and alkaline conditions. In case of TNT degradation, the rate of degradation was the fastest at pH 11. Approximately 82% TOC decrease in the TNT degradation was achieved after 150 min, whereas TOC decrease in RDX and HMX was 24% and 59%, respectively. Nitrate, nitrite, and ammonium ions were detected as the nitrogen byproducts from the photocatalysis, and more than 50% of the total nitrogen was recovered as nitrate ion in every explosives.

scholarly journals PHOTOCATALYTIC SOLAR OXIDATION OF ACESULFAME-K. EFFECT OF INITIAL pH, CATALYST DOSE AND OXIDANT CONCENTRATION

2020 ◽  
Author(s):  
Julio César Morales Mejía ◽  
Karla Ibette Anselmo Cervantes ◽  
Iván García Mendoza ◽  
Rafael Almanza
Keyword(s):  
Concentration Ratio ◽  
Photocatalytic Oxidation ◽  
Research Work ◽  
Reaction Conditions ◽  
Photocatalytic Reactor ◽  
Initial Concentration ◽  
Oxidant Concentration ◽  
Initial Ph ◽  
Parabolic Collector ◽  
The Impact

Aqueous acesulfame-K was oxidized in a pilot solar photocatalytic reactor, equipped with a compound parabolic collector (CPC). The reactor has an area of 0.40 m2 of CPC collectors with geometrical concentration ratio of 1 and a simple mechanical configuration. The experiments of photocatalytic oxidation of acesulfame-K were performed by treating 2 L of water with an initial concentration of 15 mg/L. The photocatalyst used was P25 (Aeroxide TiO2) from Evonik. One of the goals of the research work was to find a set of conditions to efficiently remove this emerging concern pollutant. Results allowed proposing a set of reaction conditions that lead to a high removal of acesulfame-K. In addition, the experimental design allowed determining the effect of initial pH as well as the impact of initial concentrations of photocatalyst and chemical oxidant. The removal efficiency of acesulfame-K and related UV-absorbing species reached values up to 96-99 % and there was not a quantifiable amount of intermediate products (analyzed as UV absorbing species). Despite reaction time was fixed in 3 h for all the experiments, oxidation efficiencies higher than 95 % were reached at 2 h of reaction or even before.

scholarly journals PHOTOCATALYTIC SOLAR OXIDATION OF ACESULFAME-K. EFFECT OF INITIAL pH, CATALYST DOSE AND OXIDANT CONCENTRATION

2021 ◽  
Vol 37 ◽  
Author(s):  
Julio César Morales Mejía
Keyword(s):  
Concentration Ratio ◽  
Photocatalytic Oxidation ◽  
Research Work ◽  
Reaction Conditions ◽  
Photocatalytic Reactor ◽  
Initial Concentration ◽  
Oxidant Concentration ◽  
Initial Ph ◽  
Parabolic Collector ◽  
The Impact

Aqueous acesulfame-K was oxidized in a pilot solar photocatalytic reactor, equipped with a compound parabolic collector (CPC). The reactor has an area of 0.40 m2 of CPC collectors with geometrical concentration ratio of 1 and a simple mechanical configuration. The experiments of photocatalytic oxidation of acesulfame-K were performed by treating 2 L of water with an initial concentration of 15 mg/L. The photocatalyst used was P25 (Aeroxide TiO2) from Evonik. One of the goals of the research work was to find a set of conditions to efficiently remove this emerging concern pollutant. Results allowed proposing a set of reaction conditions that lead to a high removal of acesulfame-K. In addition, the experimental design allowed determining the effect of initial pH as well as the impact of initial concentrations of photocatalyst and chemical oxidant. The removal efficiency of acesulfame-K and related UV-absorbing species reached values up to 96-99 % and there was not a quantifiable amount of intermediate products (analyzed as UV absorbing species). Despite reaction time was fixed in 3 h for all the experiments, oxidation efficiencies higher than 95 % were reached at 2 h of reaction or even before.

Preparation of Visible Light Response K6SiW11O39SnII for Photocatalytic Degradation of Acid Brilliant Scarlet

2012 ◽  
Vol 476-478 ◽  
pp. 2005-2008
Author(s):  
Xiu Hua Zhu ◽  
Jia Huan Liu ◽  
Li Li Zhao ◽  
Peng Yuan Wang
Keyword(s):  
Aqueous Solution ◽  
Solar Radiation ◽  
Visible Light ◽  
Photocatalytic Degradation ◽  
Light Response ◽  
Photocatalytic Decomposition ◽  
Initial Concentration ◽  
Environmental Friendly ◽  
Visible Light Response ◽  
Initial Ph

Environmental friendly materials, K6SiW11O39SnⅡ(abbreviated as SiWSn), was synthesized, which is visible light response photocatalyst. The photocatalytic decomposition of Acid Brilliant Scarlet (abbreviated as ABS) aqueous solution with SiWSn was investigated using a broad spectrum of solar radiation. The results showed that the photocatalytic degradation efficiency of ABS with SiWSn was affected by the initial pH of ABS solution, the amount of SiWSn and the photolysis time. When the initial pH of ABS solution was 5, the initial concentration of that (20mL) was 3mg L-1, the concentration of SiWSn was 1.25g L-1, and it was irradiated 4h under the sunlight, the discoloration rate of which was 71.4%.

scholarly journals Influence of Operating Parameters on Photocatalytic Oxidation of 2,4-Dichlorofenol in Aqueous Solution by TiO2/Stainless Steel Photocatalytic Membrane

2021 ◽  
Vol 11 (24) ◽  
pp. 11664
Author(s):  
Liliana Bobirică ◽  
Constantin Bobirică ◽  
Giovanina Iuliana Lupu ◽  
Cristina Orbeci
Keyword(s):  
Stainless Steel ◽  
Photocatalytic Degradation ◽  
Photocatalytic Oxidation ◽  
Oxidation Process ◽  
Organic Substrate ◽  
Molar Ratio ◽  
Operating Parameters ◽  
Photocatalytic Reactor ◽  
Initial Concentration ◽  
Working Solution

The influence of some operating parameters of an UV photocatalytic reactor with TiO2/stainless steel photocatalytic membrane on the photocatalytic oxidation of 2,4-dichlorophenol from aqueous solutions was studied in this paper. It was shown that the pH of the working solution substantially influences the photocatalytic degradation of the organic substrate, with the degradation efficiency increasing with decreasing the pH of the working solution by a maximum corresponding to pH 3. The rate constant of the photocatalytic oxidation process is about twice as high at pH 3 comparative with pH 7 for the same initial concentration of the organic substrate. The molar ratio of hydrogen peroxide/organic substrate also influences the photocatalytic oxidation process of the organic substrate. The results obtained in this paper highlight the fact that a stoichiometric molar ratio is favorable for the photocatalytic degradation of 2,4-dichlorophenol. It has also been shown that the initial concentration of the organic substrate influences the rate of photocatalytic degradation. It appears that the rate of photocatalytic degradation decreases with the increasing of initial concentration of 2,4-dichlorophenol.

scholarly journals Influence of pH on the solubility of arsenic in heavily contaminated soils / Wpływ pH na rozpuszczalność arsenu w glebach silnie zanieczyszczonych

2013 ◽  
Vol 24 (3) ◽  
pp. 7-11 ◽  
Author(s):  
Leszek Gersztyn ◽  
Anna Karczewska ◽  
Bernard Gałka
Keyword(s):  
Contaminated Soils ◽  
Arsenic Concentration ◽  
Organic Matter Content ◽  
Matter Content ◽  
Soil Samples ◽  
Carbonate Content ◽  
Ore Processing ◽  
Initial Ph ◽  
Alkaline Conditions ◽  
The Impact

Abstract The aim of this study was to determine the impact of pH on arsenic solubility in soils heavily contaminated by the former arsenic industry. For the purpose of the study, three soil samples were collected from the area affected by ore processing in Złoty Stok. Soils differed in initial pH, calcium carbonate content, organic matter content and total arsenic concentration. The amounts of arsenic released from soils at various pH were measured using extraction tests, where soil samples were shaken with various doses of HCl and NaOH in the presence of 0.01 mol • dm−3 CaCl2 as the background solution. Arsenic solubility in soils was considerably low at neutral or slightly acidic pH and increased considerably in both strongly acidic and alkaline conditions. The importance of these effects for environmental risk was discussed.

scholarly journals Effects of KBr and KI on Photocatalytic Degradation of Dye W-7G with Nano-TiO2 as Catalyst

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Chao Zou ◽  
Qi-Jin Geng ◽  
Jing-Tuo Zhu ◽  
Chen Jing ◽  
Wen Zhong ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
Inorganic Salt ◽  
Ph Value ◽  
Nano Tio2 ◽  
Photocatalytic Reactor ◽  
Theoretical Support ◽  
Maximum Value ◽  
Degradation Of Dyes ◽  
Bubbling Fluidized Bed ◽  
Alkaline Conditions

To investigate the influence of inorganic salt on the photocatalytic degradation, the effects of KBr and KI at various concentrations and pH values on the photocatalytic degradation of dye W-7G using nanoscaled titanium dioxide as photocatalyst in a bubbling fluidized bed photocatalytic reactor (BFBPR) were studied. The results indicated that the degradation apparent rate constant ( K app ) of the system with KI was clearly higher than that with KBr under acidic or alkaline conditions. And the maximum value of K app (0.01127) appeared at the KI concentration of 0.075 g L-1 with a pH value of 9.37, meaning the highest degradation efficiency. Furthermore, the possible mechanism of photocatalytic degradation of W-7G in the presence of KBr and KI was proposed, which could provide a theoretical support for the further study of inorganic salt effects on the photocatalytic degradation of dyes.

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.

Enhanced Photocatalytic Degradation of Antibiotic and Hydrogen Production by Iron Doped Cerium(IV) Oxide

2021 ◽  
Vol 21 (5) ◽  
pp. 3099-3106
Author(s):  
Yang Hsu ◽  
Joy Thomas ◽  
Chang Tang Chang ◽  
Chih Ming Ma
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Production ◽  
Photocatalytic Degradation ◽  
Removal Rate ◽  
Emerging Contaminant ◽  
Total Removal ◽  
Initial Concentration ◽  
The Poor ◽  
Initial Ph ◽  
Pl Emission

Norfloxacin (NF) is an emerging antibiotic contaminant due to its significant accumulation in the environment. Photocatalytic degradation is an effective method for removing emerging contaminant compounds in aqueous solution; however, it is not commonly applied because of the poor solubility of contaminant compounds in water. In this study, a photocatalytic degradation experiment was carried out on NF using a self-made ceria catalyst. At an initial concentration of NF of 2.5 mg L−1, the dosage of CeO2 was 0.1 g L−1 photocatalyst in water, and the initial pH of the NF solution was 8.0. With a reaction time of 180 min, the total removal rate of NF could reach 95%. Additionally, the studies on hydrogen production show that the maximum hydrogen production with 2% Fe–CeO2 can reach 25,670 μmol h−1 g−1 under close to 8 W of 365 nm, a methanol concentration of 20%, and a catalyst dose of 0.1 g L−1 photocatalyst in water. Furthermore, the intensities of photoluminescence (PL) emission peaks decreased with increased Fe-doped amounts on CeO2, suggesting that the irradiative recombination seemed to be weakened.

Study on Fiber Optical Reactor Catalytic Degradation of Oxytetracycline

2013 ◽  
Vol 361-363 ◽  
pp. 1020-1023
Author(s):  
Ying Zheng ◽  
Lin Xia Gao
Keyword(s):  
Photocatalytic Degradation ◽  
Removal Rate ◽  
Catalytic Degradation ◽  
Photocatalytic Reaction ◽  
Positive Role ◽  
Fiber Optical ◽  
Effects Of Ph ◽  
Alkaline Conditions ◽  
The Impact ◽  
Degradation Effect

Antibiotics have played a positive role in human health and. But underutilized antibiotics can’t be removed by normal treatment. The paper study the impact of fiber optical reactor catalytic degradation of oxytetracycline and step to examine the degradation effect. The results show that: temperature increases within a certain range contribute to the degradation of the oxytetracycline. Effects of pH on the photocatalytic reaction were significant, and alkaline conditions is more conducive to oxytetracycline photocatalytic degradation. In the concentration range of the experimental study, oxytetracycline photocatalytic degradation was inhibited by the higher initial concentration. Catalyst promoted oxytetracycline degradation, its addition amount on photocatalytic reaction influence is relatively large, when the pH is 7, with the increase of nano-TiO2 dosage, removal rate was gradually increased. The degradation rate of oxytetracycline in different reaction process can be shown as: photocalysis＞photolysis＞hydrolysis in this research.

Photocatalytic degradation of methylene blue from aqueous solutions using nanopillars-TiO2 thin films: Batch reactor studies

2018 ◽  
Vol 18 (3) ◽  
pp. 81-91 ◽  
Author(s):  
C. Lalhriatpuia
Keyword(s):  
Thin Films ◽  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Organic Carbon ◽  
Photocatalytic Degradation ◽  
Batch Reactor ◽  
Tio2 Thin Films ◽  
Initial Concentration ◽  
Bet Specific Surface Area ◽  
Interfering Ions

Nanopillars-TiO2 thin films was obtained on a borosilicate glass substrate with (S1) and without (S2) polyethylene glycol as template. The photocatalytic behaviour of S1 and S2 thin films was assessed inthe degradation of methylene blue (MB) dye from aqueous solution under batch reactor operations. The thin films were characterized by the SEM, XRD, FTIR and AFM analytical methods. BET specific surface area and pore sizes were also obtained. The XRD data confirmed that the TiO2 particles are in its anatase mineral phase. The SEM and AFM images indicated the catalyst is composed with nanosized pillars of TiO2, evenly distributed on the surface of the substrate. The BET specific surface area and pore sizes of S1 and S2 catalyst were found to be 5.217 and 1.420 m2/g and 7.77 and 4.16 nm respectively. The photocatalytic degradation of MB was well studied at wide range of physico-chemical parameters. The effect of solution pH (pH 4.0 to 10.0) and MB initial concentration (1.0 to 10.0 mg/L) was extensively studied and the effect of several interfering ions, i.e., cadmium nitrate, copper sulfate, zinc chloride, sodium chloride, sodium nitrate, sodium nitrite, glycine, oxalic acid and EDTA in the photocatalytic degradation of MB was demonstrated. The maximum percent removal of MB was observed at pH 8.0 beyond which it started decreasing and a low initial concentration of the pollutant highly favoured the photocatalytic degradation using thin films and the presence of several interfering ions diminished the photocatalytic activity of thin films to some extent. The overall photocatalytic activity was in the order: S2 > S1 > UV. The photocatalytic degradation of MB was followed the pseudo-first-order rate kinetics. The mineralization of MB was studied with total organic carbon measurement using the TOC (total organic carbon) analysis.

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