Photodegradation of Sulfadiazine in Aqueous Solution and the Affecting Factors

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.

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Photodegradation of sulphadimethoxine in water by medium pressure UV lamp

Water Science & Technology ◽

10.2166/wst.2008.668 ◽

2008 ◽

Vol 58 (5) ◽

pp. 1147-1154 ◽

Cited By ~ 16

Author(s):

Y. Lester ◽

I. Gozlan ◽

D. Avisar ◽

H. Mamane

Keyword(s):

Reaction Rate ◽

Uv Light ◽

Acid Base ◽

Direct Photolysis ◽

Medium Pressure ◽

Ph Values ◽

Photodegradation Rate ◽

Photodegradation Products ◽

Uv Lamp ◽

The Impact

The photodegradation rate of sulphadimethoxine (SMT) in water was studied under polychromatic UV light, in a bench scale apparatus. SMT photolysis was carried out at pH levels of 2.5, 6.5 and 10 to study the impact of acid base properties on the degradation of SMT. The highest SMT photolysis fluence based rate was found at pH = 2.5 (k=7.22 × 10−4 cm2/mJ) and the lowest rate at pH = 10 (k=4.72 × 10−4 cm2/mJ), thus the reaction rate decreases with an increase in pH between pH values of 2.5–10. Results indicated that direct photolysis is not satisfactory for degradation of SMT by polychromatic UV lamp as a fluence of approximately 7,000 mJ/cm2 is needed to break down 99% of SMT at pH 6.5. The photodegradation products of SMT were studied at various pH values. Photodegradation of SMT results in dissimilar relative amounts of intermediates formed at different pH values which may exert a photon demand and impact on SMT photodegradation rate.

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Effect of Sunlight and Ultraviolet Light on Dissipation of Fipronil Insecticide in Two Soils and Effect of pH on its Persistence in Aqueous Medium

Air Soil and Water Research ◽

10.4137/aswr.s14847 ◽

2014 ◽

Vol 7 ◽

pp. ASWR.S14847 ◽

Cited By ~ 2

Author(s):

Ankita Verma ◽

Anjana Srivastava ◽

Shailendra Singh Chauhan ◽

Prakash Chandra Srivastava

Keyword(s):

Aqueous Medium ◽

Half Life ◽

Uv Light ◽

Light Exposure ◽

Clay Loam ◽

Sandy Clay Loam ◽

First Order ◽

First Order Kinetics ◽

Sandy Clay ◽

Uv Lamp

In a laboratory investigation, the effect of natural sunlight and UV light exposure on dissipation of fipronil insecticide from two soils (clay loam and sandy clay loam) and the effect of pH on the persistence of fipronil in aqueous medium were studied. Dissipation of fipronil insecticide under sunlight followed biphasic first order kinetics in both soils. The half-life of the insecticide in sandy clay loam type soil was found to be 5.71 days for the first faster phase and 23.88 days for the second slower phase, whereas, in clay loam soil, the corresponding half-lives were 4.02 and 8.38 days, respectively. Under the UV light exposure, the dissipation of fipronil followed a single phase first order kinetics in both the soils with a half-life of 3.77 days in clay loam and 5.37 days in sandy clay loam, respectively. Residues of fipronil dissipated faster in clay loam than in sandy clay loam under both sunlight and UV lamp light. As compared to sunlight, dissipation was found to be faster under UV lamp light. Persistence of fipronil in aqueous medium under different pH conditions revealed that fipronil residues were below the limit of detection (LOD), <0.05 μg g−1, after 40 days of sampling at all the three pH. The dissipation of fipronil from aqueous medium increased with increasing pH from 5.0 to 9.0; the corresponding half-lives were 14.12, 9.83, and 6.76 days at pH 5.0, 7.0, and 9.0, respectively.

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

Environmental Engineering Research ◽

10.4491/eer.2019.196 ◽

2019 ◽

Vol 25 (4) ◽

pp. 529-535 ◽

Cited By ~ 1

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 TiO2 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 TiO2 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-1 violet-3B dye achieved 96% color removal within 240 min of irradiation in the presence of C-N-codoped TiO2 catalyst, and approximately 44% TOC was removed as a result of the mineralization.

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

Journal of Photocatalysis ◽

10.2174/2665976x02666210629104521 ◽

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.

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Photocatalysed Oxidation of Toxic Organics

Water Science & Technology ◽

10.2166/wst.1987.0218 ◽

1987 ◽

Vol 19 (3-4) ◽

pp. 381-390 ◽

Cited By ~ 8

Author(s):

M. Brett Borup ◽

E. Joe Middlebrooks

Keyword(s):

Hydrogen Peroxide ◽

Ultraviolet Radiation ◽

Organic Compounds ◽

Hydroxyl Radicals ◽

Reaction Rate ◽

Oxidation Process ◽

Dimethyl Phthalate ◽

First Order ◽

Toxic Organics ◽

Catalyzed Oxidation

The feasibility of treating water contaminated by two toxic organic compounds with an ultraviolet light catalyzed oxidation process using hydrogen peroxide as an oxidant is investigated. In this process hydrogen peroxide is decomposed by ultraviolet radiation producing hydroxyl radicals. The hydroxyl radicals will then oxidize organic compounds via a complex chain of radical reactions. Tests showed that this photooxidation process could successfully remove isophorone and dimethyl phthalate from contaminated waters. A reaction rate expression which adequately describes the process was developed. The reaction rate was found to be first order with respect to hydrogen peroxide concentration, zero order with respect to organic concentration and a function of ultraviolet radiation intensity. The reaction did not exhibit autocatalytic characteristics.

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Estudios fotoquímicos y electroquímicos de complejos lantánidos de 6-(hidroximetil)piridin- 2-carboxaldehído[2- metilpirimidina-4,6-diil] bishidrazona

Revista Colombiana de Química ◽

10.15446/rev.colomb.quim.v43n1.50540 ◽

2015 ◽

Vol 43 (1) ◽

pp. 5-11 ◽

Cited By ~ 8

Author(s):

María Alejandra Fernandez ◽

Juan Camilo Barona ◽

Dorian Polo-Cerón ◽

Manuel N. Chaur

Keyword(s):

Uv Light ◽

Condensation Reaction ◽

Quantum Yields ◽

Consecutive Reaction ◽

Metal Centers ◽

First Order ◽

Fluorescence Quantum Yields ◽

H Nmr ◽

First Order Kinetics ◽

Uv Light Irradiation

Herein we report the synthesis of the 6-(hydroxymethyl)pyridine-2- carboxaldehyde[2-methyl-pyrimidine- 4,6-diyl]bis-hydrazone by a condensation reaction between 6-(hydroxymethyl) picolinaldehyde with 4,6-(bis-hydrazino)-2- methylpyrimidine. This bis-hydrazone can be visualized as a two-arm system which exhibits photochemical induced [E,E]/[E,Z]/[Z,Z’] isomerizations and double coordination to metal centers. Configurational changes, upon UV light irradiation, were followed over time by 1 H NMR, establishing that isomerization, in both arms, is a consecutive reaction that follows first-order kinetics (k1 = 4.06 x 10-4 s-1 and k2 = 2.80 x 10-4 s-1). Furthermore, the synthesis of bis-hydrazone metal complexes with La (III) and Sm (III) ions was achieved; subsequently, the absorption and emission properties of these complexes were studied, determining the fluorescence quantum yields, 𝟇La= 0.2024 and 𝟇Sm= 0.1413. Electrochemical studies of the complexes were conducted by square wave voltammetry, demonstrating that the bis-hydrazone and its complexes are electroactive species between +1.5 and -2.5 V.

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Kinetics and mechanism of the osmium-tetroxide-catalysed oxidation of mandelate ion by hexacyanoferrate(III) ion

Australian Journal of Chemistry ◽

10.1071/ch9682913 ◽

1968 ◽

Vol 21 (12) ◽

pp. 2913 ◽

Cited By ~ 13

Author(s):

NP Singh ◽

VN Singh ◽

MP Singh

Keyword(s):

Benzoic Acid ◽

Oxidation Product ◽

Osmium Tetroxide ◽

Reaction Rate ◽

Zero Order ◽

Ion Concentration ◽

First Order ◽

First Order Kinetics ◽

Catalysed Oxidation ◽

Hydroxyl Ion

The osmium-tetroxide-catalysed oxidation of mandelate ion by hexacyanoferrate(111) ion has been studied kinetically. The reaction rate has been found to be independent of hexacyanoferrate(111) ion while the order with respect to both osmium tetroxide and mandelate ion comes out to be unity. The reaction rate follows first-order kinetics at low hydroxyl ion concentration and becomes zero order at higher concentrations. The course of the reaction has been considered to proceed through the formation of an activated mandelate-OsO4, complex which decomposes in alkaline medium giving reduced osmium(V1) followed by a fast oxidation by hexacyanoferrate(111) ion. The probable course of the reactions is also described with the help of its oxidation product, benzoic acid.

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Disinfection effects on E. coli using TiO2/UV and solar light system

Water Science & Technology Water Supply ◽

10.2166/ws.2002.0023 ◽

2002 ◽

Vol 2 (1) ◽

pp. 181-190 ◽

Cited By ~ 8

Author(s):

I.-H. Cho ◽

I.-Y. Moon ◽

M.-H. Chung ◽

H.-K. Lee ◽

K.-D. Zoh

Keyword(s):

Light Intensity ◽

Flow Rate ◽

Alternative Energy ◽

Advanced Oxidation Process ◽

Uv Light ◽

Solar Light ◽

Survival Ratio ◽

E Coli ◽

First Order ◽

First Order Kinetics

First, a continuous flow TiO2/UV reactor was designed and developed in order to examine E. coli disinfection effect using UV light. The optimum conditions for disinfection such as flow rate, light intensity, TiO2 concentration, initial E. coli concentration were examined. The results are as follow (i) The use of the quartz device and TiO2 (anatase) resulted in killing of E. coil within minutes. (ii) Photocatalytic disinfection with UV light in the presence of TiO2 more effectively killed E. coli than UV or TiO2 adsorption only. (iii) As flow rate increased, the survival ratio of E. coli decreased, but over 3 L/min of flow rate, the efficiency was limited. (iv) E. coli survival ratio decreased linearly with increasing UV light intensity. (v) The dosage of TiO2 affected the E. coli disinfection efficiency, and above 0.1 wt% TiO2 concentration, the disinfection was less effective because TiO2 particles may result in screening off the light. (ri) The disinfection reaction follows first-order kinetics. Secondly, outdoor experiments with natural sunlight instead of artificial UV light in TiO2 reactors were also conducted to investigate alternative energy source applicability on E. coli disinfection. It is found that the presence of clouds in the sky markedly increased the time required for killing E. coli and the bacteria cells also disappeared with a first-order kinetics. On the basis of these experimental observations, the disinfection of E. coli using TiO2 under solar light irradiation can be a feasible application of the advanced oxidation process.

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Macrokinetics and Mechanism of Phenol Solution Degradated by Fe3+/Ce4+ Doped TiO2 Particles

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.955-959.411 ◽

2014 ◽

Vol 955-959 ◽

pp. 411-414

Author(s):

Yu Fei Wang ◽

Long Yan ◽

Jian Li

Keyword(s):

Degradation Process ◽

Isobutyric Acid ◽

Phenol Solution ◽

First Order ◽

Degradation Reactions ◽

First Order Kinetics ◽

Before And After ◽

Mechanism Of Degradation ◽

Butanedioic Acid ◽

Dynamic Cycle

Fe3+/Ce4+doped TiO2particles was prepared and used for degradation of phenol solution, the macrokinetics and mechanism of degradation process was proposed by GC-MS, and Fe3+/Ce4+-doped TiO2particles before and after treated phenol was also compared by TEM. The experimental results showed that COD degradation reactions in static and dynamic cycle process are in accordance with first-order kinetics from the macro effects, phenol can be oxidized to intermediates, such as isobutyric acid, malonic acid, para-benzoquinone, butenic acid, ethanedioic acid, maleic acid, butanedioic acid, o-dihydroxybenzene, paradioxybenzene and dioxybenzene, indicating that Fe3+/Ce4+-doped TiO2particles are beneficial to some oxidation formation. Moreover, the shapes of Fe3+/Ce4+-doped TiO2particles after treated phenol displays aggregated.

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Photodegradation of amoxicillin in aqueous solution under simulated irradiation: influencing factors and mechanisms

Water Science & Technology ◽

10.2166/wst.2013.033 ◽

2013 ◽

Vol 67 (7) ◽

pp. 1605-1611 ◽

Cited By ~ 10

Author(s):

Qian Zhao ◽

Li Feng ◽

Xiang Cheng ◽

Chao Chen ◽

Liqiu Zhang

Keyword(s):

Aqueous Solution ◽

Singlet Oxygen ◽

Natural Waters ◽

Pure Water ◽

Chemical Species ◽

Xenon Lamp ◽

First Order ◽

First Order Kinetics ◽

Photodegradation Rate ◽

Pseudo First Order

This paper investigated the effects of selected common chemical species in natural waters (HCO3−, NO3− and humic acids (HA)) on the photodegradation of amoxicillin (AMO) under simulated irradiation using a 300 W xenon lamp. Quenching experiments were carried out to explore the mechanisms of AMO photodegradation. The results indicated that AMO photodegradation followed pseudo-first-order kinetics. Increasing AMO concentration from 100 to 1,000 μg L−1 led to the decrease in the photodegradation rate constant from 0.2411 to 0.1912 min−1. The presence of NO3− and HA obviously inhibited the photodegradation rate of AMO because they can compete for photons with AMO. Bicarbonate, as a hydroxyl radical (·OH) scavenger, also adversely affected AMO photodegradation. Quenching experiments in pure water suggested that AMO could undergo self-sensitized photooxidation via ·OH and singlet oxygen (1O2), accounting for AMO removal of 34.86 and 8.26%, respectively. In HA solutions, the indirect photodegradation of AMO was mostly attributed to the produced ·OH (22.37%), 1O2 (24.12%) and 3HA* (20.80%), whereas the contribution of direct photodegradation was to some extent decreased.

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