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

2002 ◽  
Vol 2 (1) ◽  
pp. 181-190 ◽  
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.

Studies on photocatalytic activity of the synthesised TiO2 and Ag/TiO2 photocatalysts under UV and sunlight irradiations

2011 ◽  
Vol 63 (3) ◽  
pp. 377-384 ◽  
Author(s):  
R. Vaithiyanathan ◽  
T. Sivakumar
Keyword(s):  
Uv Light ◽  
Sol Gel ◽  
Solar Light ◽  
Light Sources ◽  
Tio2 Photocatalysts ◽  
First Order ◽  
First Order Kinetics ◽  
Radiation Sources ◽  
Silver Metal ◽  
Comprehensive Study

Photocatalytic decolorisation and degradation of Reactive Red 120 (RR 120) has been investigated under UV (365 nm) and solar light as radiation sources using synthesised nano titania catalyst prepared via sol-gel method. The study encompassed calcination of synthesised titania catalyst at a range of temperature up to 1,000°C. The effects of calcination temperature on titania catalyst have been evaluated on the decolorisation of RR 120. The analysis revealed complete decolorisation of dye solution in 100 min under UV light with the TiO2 catalyst calcined at 200°C. Only a maximum of 47% dye decolorisation was achieved under sunlight in 4 h with no improvement even after prolonged irradiation. In an endeavour to improve the catalytic activity, bare titania was modified with silver metal and a comprehensive study on the characteristics of silver modified catalyst was made. The result was an enhancement of the rate of decolorisation of dye under both UV and solar light sources. All the catalysts were characterised by XRD and BET analyses. Optimisation of the degradation of RR 120 has been carried out using the unmodified catalyst by varying the amount of catalyst, substrate concentration, pH of dye solution. Effects of addition of small amounts of various oxidants such as H2O2, KBrO3 and (NH4)2S2O8 have also been studied. Pseudo first order kinetics was observed in the photocatalytic decolorisation of dye. The mineralisation of RR 120 was monitored by TOC analysis.

Photocatalytic Discolouration of Solutions of Reactive Dyes in the Presence of H2O2

1995 ◽  
Vol 30 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Deng Nansheng ◽  
Tian Shizhong ◽  
Xia Mei
Keyword(s):  
Photochemical Reaction ◽  
Uv Light ◽  
Reactive Dyes ◽  
Solar Light ◽  
Rate Equations ◽  
Oh Radical ◽  
Test Results ◽  
Dye Molecules ◽  
First Order ◽  
Dye Solutions

Abstract Tests for the photocatalytic degradation of solutions of three reactive dyes, Red M-5B, Procion Blue MX-R and Procion Black H-N, in the presence of H2O2 were carried out. When the solutions of the three reactive dyes were irradiated by UV or solar light, the colour of the solutions disappeared gradually. A statistical analysis of the test results indicated a linear relation between the concentration of dyes and the time of irradiation. The discolouration reaction of the solutions was of the first order. Rate equations for the discolouration reactions of dye solutions were developed. The dark reactions or the dye solutions containing H2O2 were very slow, illustrating that the photochemical reaction played a very important role. It was demonstrated that UV light and solar light (300 to 380 nm) photolyzes the HO and that the resulting OH radical reacts with the dye molecules and destroys the chromophore.

UV Based Advanced Oxidation Process for Degradation of Ciprofloxacin: Reaction Kinetics, Effects of Interfering Substances and Degradation Product Identification

2021 ◽  
Author(s):  
Bijoli Mondal ◽  
Shib Sankar Basak ◽  
Arnab Das ◽  
Sananda Sarkar ◽  
Asok Adak
Keyword(s):  
Organic Compounds ◽  
Advanced Oxidation Process ◽  
Oxidation Process ◽  
Uv Light ◽  
Degradation Products ◽  
Irradiation Time ◽  
Advanced Oxidation ◽  
Quantum Yields ◽  
Photon Flux ◽  
First Order

Abstract In the photochemical UV-H2O2 advanced oxidation process, H2O2 absorbs UV light and is decomposed to form hydroxyl radicals (OH·), which are highly excited and reactive for electron-rich organic compounds and hence can degrade organic compounds. In the present work, the UV-H2O2 process was investigated to degrade ciprofloxacin (CIP), one of India's widely used antibiotics, from aqueous solutions using a batch type UV reactor having photon flux = 1.9 (± 0.1) ×10-4 Einstein L-1 min-1. The effects of UV irradiation time on CIP degradation were investigated for both UV and UV-H2O2 processes. It was found that about 75% degradation of CIP was achieved within 60 s with initial CIP concentration and peroxide concentration of 10 mg L-1 and 1 mol H2O2/ mol CIP, respectively, at pH of 7(±0.1) and fluence dose of 113 mJ cm-2. The experimental data were analyzed by the first-order kinetics model to find out the time- and fluence-based degradation rate constants. Under optimized experimental conditions (initial CIP concentration, pH and H2O2 dose of 10 mg L-1, 7(±0.1) and 1.0 mol H2O2 / mol CIP, respectively), the fluence-based pseudo-first-order rate constant for the UV and UV-H2O2 processes were determined to be 1.28(±0.0) ×10-4 and 1.20(±0.04) ×10-2 cm2 mJ-1 respectively. The quantum yields at various pH under direct UV were calculated. The impacts of different process parameters such as H2O2 concentration, solution pH, initial CIP concentration, and wastewater matrix on CIP degradation were also investigated in detail. CIP degradation was favorable in acidic conditions. Six degradation products of CIP were identified. Results clearly showed the potentiality of the UV-H2O2 process for the degradation of antibiotics in wastewater.

scholarly journals Removal of Polyvinyl Alcohol Using Photoelectrochemical Oxidation Processes Based on Hydrogen Peroxide Electrogeneration

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Kai-Yu Huang ◽  
Chih-Ta Wang ◽  
Wei-Lung Chou ◽  
Chi-Min Shu
Keyword(s):  
Hydrogen Peroxide ◽  
Light Intensity ◽  
Removal Efficiency ◽  
Flow Rate ◽  
Current Density ◽  
Uv Light ◽  
Supporting Electrolyte ◽  
Oxygen Flow Rate ◽  
Oxygen Flow ◽  
Solution Ph

This study investigates the removal efficiency of PVA from aqueous solutions using UV irradiation in combination with the production of electrogenerated hydrogen peroxide (H2O2) at a polyacrylonitrile-based activated carbon fiber (ACF) cathode. Three cathode materials (i.e., platinum, graphite, and ACF) were fed with oxygen and used for the electrogeneration of H2O2. The amount of electrogenerated H2O2produced using the ACF cathode was five times greater than that generated using the graphite cathode and nearly 24 times greater than that from platinum cathode. Several parameters were evaluated to characterize the H2O2electrogeneration, such as current density, oxygen flow rate, solution pH, and the supporting electrolyte used. The optimum current density, oxygen flow rate, solution pH, and supporting electrolyte composition were found to be 10 mA cm−2, 500 cm3 min−1, pH 3, and Na2SO4, respectively. The PVA removal efficiencies were achieved under these conditions 3%, 16%, and 86% using UV, H2O2electrogeneration, and UV/H2O2electrogeneration, respectively. A UV light intensity of 0.6 mW cm−2was found to produce optimal PVA removal efficiency in the present study. A simple kinetic model was proposed which confirmed pseudo-first-order reaction. Reaction rate constant (kap) was found to depend on the UV light intensity.

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

2015 ◽  
Vol 43 (1) ◽  
pp. 5-11 ◽  
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

<p>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.</p>

Radicals induced from peroxomonosulfate by nanoscale zero-valent copper in the acidic solution

2016 ◽  
Vol 74 (8) ◽  
pp. 1946-1952 ◽  
Author(s):  
Peng Zhou ◽  
Bei Liu ◽  
Jing Zhang ◽  
Yongli Zhang ◽  
Gucheng Zhang ◽  
...  
Keyword(s):  
Advanced Oxidation Process ◽  
Oxidation Process ◽  
Acidic Solution ◽  
Butyl Alcohol ◽  
First Order ◽  
First Order Kinetics ◽  
Tert Butyl Alcohol ◽  
Initial Ph ◽  
Reactive Radicals ◽  
Reactive Oxidant

A highly efficient advanced oxidation process for the degradation of benzoic acid (BA) during activation of peroxomonosulfate (PMS) by nanoscale zero-valent copper (nZVC) in acidic solution is reported. BA degradation was almost completely achieved after 10 min in the nZVC/PMS process at initial pH 3.0. PMS could accelerate the corrosion of nZVC in acidic to release Cu+ which can further activate PMS to produce reactive radicals. Both sulfate radical (SO4−•) and hydroxyl radical (•OH) were considered as the primary reactive oxidant in the nZVC/PMS process with the experiments of methyl (MA) and tert-butyl alcohol quenching. Acidic condition (initial pH ≤ 3.0) facilitated BA degradation and pH is a decisive factor to affect the oxidation capacity in the nZVC/PMS process. Moreover, BA degradation in the nZVC/PMS process followed the pseudo-first-order kinetics, and BA degradation efficiency increased with the increase of the nZVC dosage.

scholarly journals Use of semi-conducting bismuth sulfide as a photocatalyst for degradation of rose bengal

2011 ◽  
Vol 30 (2) ◽  
pp. 229 ◽  
Author(s):  
Shweta Sharma ◽  
Rakshit Ameta ◽  
R. K. Malkani ◽  
Suresh C. Ameta
Keyword(s):  
Light Intensity ◽  
Rose Bengal ◽  
Bismuth Sulfide ◽  
Optimum Conditions ◽  
First Order ◽  
First Order Kinetics ◽  
Degradation Of Dyes ◽  
Textile Dyeing ◽  
Rate Of Reaction ◽  
Pseudo First Order

Different methods have been adopted for the removal and degradation of dyes from effluents of textile, dyeing and printing industries. These methods have their own merits and drawbacks. In the present investigation, bismuth sulfide has been used as a photocatalyst for the degradation of rose Bengal. The effect of different parameters like the pH, concentration of dye solution, amount of semiconductor and light intensity on the rate of reaction has been investigated. The reaction follows pseudo-first order kinetics. The optimum conditions were obtained as: [rose Bengal] = 1.60·10–5 M; Bi2S3 = 0.10 g; pH = 8.5, and light intensity = 50.0 mW·cm–2. The rate constant was 4.68·10–5 sec–1. A mechanism has been proposed for the degradation of rose Bengal involving hydroxyl radicals.

scholarly journals Decolourization of Congo Red Dye using Solar/H2O2 Process

2021 ◽  
Vol 33 (6) ◽  
pp. 1294-1298
Author(s):  
R. Raja ◽  
A. Rose Venis ◽  
R. Tamil Selvan ◽  
T. Mohandas
Keyword(s):  
Light Intensity ◽  
Congo Red ◽  
Advanced Oxidation Process ◽  
Kinetic Studies ◽  
Solar Light ◽  
H2o2 Concentration ◽  
Congo Red Dye ◽  
Toc Removal ◽  
Red Dye ◽  
Removal Studies

The Congo red dye was decolourized by advanced oxidation process using solar/H2O2 method and the effect of various parameters on decolourization like pH, H2O2 concentration, dye concentration, solar light intensity, additives, COD and TOC removal studies and kinetic studies were investigated. The photodegradation process was done by exposing dye solutions with the concentration of 100 mg/L treated with 50% H2O2 to sunlight with the lux intensity range of 60,000-90,000 lux. The best possible pH 2 with an optimal H2O2 concentration of 1000 mM to achieve 100% decolourization within the period of 5 h. The kinetic studies done on H2O2 concentration also proved that the high solar light intensity leads to higher decolourization and low solar light intensity leads to lesser decolourization. Addition of additives like H2PO4 – and Cl– leads to a decrease in the rate of decolourization. The removal of COD and TOC removal was found to be 83.26% and 5.18%, respectively.

scholarly journals Abomasal emptying in sheep as related to the amount of protein entering the abomasums

1984 ◽  
Vol 52 (1) ◽  
pp. 123-129 ◽  
Author(s):  
J. Van Bruchem ◽  
T. Van Der Lende ◽  
J. G. De Swart ◽  
G. A. Bangma
Keyword(s):  
Sodium Chloride ◽  
Liquid Phase ◽  
Flow Rate ◽  
Retention Time ◽  
Soya Bean ◽  
Mean Retention Time ◽  
First Order ◽  
First Order Kinetics ◽  
Infusion Tube ◽  
Bean Protein

1. In sheep, provided with re-entrant cannulas in the caudal duodenum and with an infusion tube into the abomasal fundus, emptying of the liquid phase of the abomasal contents was studied with [57Co]EDTA. Radioactivity was measured continuously with Geiger-Müller counters placed along the re-entrant cannulas.2. It appeared that first-order kinetics could be applied to the elimination of [57Co]EDTA from the abomasum. Mean retention time of this label in the abomasum was 40–50 min.3. Infusion of a suspension of soya-bean protein in saline (9 g sodium chloride/l) caused an initially decreased rate of abomasal emptying, but after 48 h an adaptation had occurred to the original rate of emptying producing an increased volume of abomasal contents and increased flow-rate of digesta into the duodenum.

scholarly journals Photodegradation of lincomycin in aqueous solution

2006 ◽  
Vol 2006 ◽  
pp. 1-6 ◽  
Author(s):  
Agatino Di Paola ◽  
Maurizio Addamo ◽  
Vincenzo Augugliaro ◽  
Elisa García-López ◽  
Vittorio Loddo ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Uv Light ◽  
Heterogeneous Systems ◽  
Degradation Pathways ◽  
Direct Photolysis ◽  
First Order ◽  
First Order Kinetics ◽  
Pseudo First Order ◽  
Complete Mineralization

Aqueous solutions of lincomycin were irradiated with UV light in homogeneous and heterogeneous systems. Lincomycin disappeared in both systems but the presence ofTiO2noticeably accelerated the degradation of the antibiotic in comparison with direct photolysis. The rate of decomposition was dependent on the concentration of lincomycin and followed a pseudo-first-order kinetics. Photolysis involved only the oxidation of lincomycin without mineralization. Differently, the treatment withTiO2and UV light resulted in a complete mineralization of the antibiotic. The degradation pathways involved S- and N-demethylation and propyldealkylation. The mineralization of the molecule led to the formation of sulfate, ammonium, and nitrate ions.

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