Detoxification of Aqueous Solutions Containing the Commercial Pesticide Metasystox by TiO2-Mediated Solar Photocatalysis

2005 ◽  
Vol 129 (1) ◽  
pp. 74-79 ◽  
Author(s):  
A. Arques ◽  
A. García-Ripoll ◽  
R. Sanchís ◽  
L. Santos-Juanes ◽  
A. M. Amat ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Surface Tension ◽  
Titanium Dioxide ◽  
Active Species ◽  
Test Laboratory ◽  
Solar Irradiation ◽  
Complete Elimination ◽  
Solar Photocatalysis ◽  
Order Of Magnitude ◽  
Commercial Pesticide

A commercial pesticide, namely metasystox, has been chosen to study its detoxification in aqueous solution by means of solar photocatalysis employing titanium dioxide. Initial toxicity/biodegradability has been checked by means of active sludges respirometry and the Zahn–Wellens test. Laboratory scale experiments indicate that significant detoxification (by approximately one order of magnitude) of a 0.05g∕L solution of the active species can be achieved in only 3h of solar irradiation due to the nearly complete elimination of the active compound, methyloxydemeton. In this case, total organic carbon (TOC) measurements cannot be used to evaluate the process as nonactive organic excipients interfere in the measurement. The experiment has been scaled-up to 25L in a solar pilot plant; also in this case more than 75% elimination of methyloxydemeton is achieved in 5h irradiation (∼1400kJ). Besides detoxification (80% initial inhibition of the active sludges and 20% at the end of the experiments), and moderate TOC reduction (∼20%) are observed together with an increase of the surface tension of the solutions, probably due to elimination of excipients having surfactant properties.

scholarly journals Modeling and optimization of the photocatalytic degradation of Tartrazine in aqueous solution

2021 ◽  
pp. 133-145
Author(s):  
Mirvet Assassi ◽  
Farid Madjene ◽  
Sara Harchouche ◽  
Hind Boulfiza
Keyword(s):  
Aqueous Solution ◽  
Reaction Time ◽  
Photocatalytic Degradation ◽  
Batch Reactor ◽  
Heterogeneous Photocatalysis ◽  
Active Species ◽  
Influential Factor ◽  
Solar Irradiation ◽  
Uv Lamp ◽  
Positive Effect

The application of heterogeneous photocatalysis process using ZnO photocatalyst for the degradation of Tartrazine (TRZ) dye in aqueous solution was investigated in a batch reactor. The estimation, the comparison of the parameter?s effects and the optimization of the removal yield of TRZ were realized by using Box-Behnken experimental design (BBD). The results suggested that the most influential factor on the photocatalytic degradation of the dye was the initial TZR concentration with an effect of (-23.24), the second in the order was the amount of the catalyst with an effect of (+18.09), the third was the reaction time with an effect of (+15.38) and the fourth was stirring speed with a positive effect of (+4.41). The model obtained by BBD led to the following optimal conditions for degradation yield of TRZ: initial concentration of TZR equal to 20.035 mg/L, reaction time equal to 88.635 min, 0.6409 mg/L of ZnO amount and 404.9 rpm for the stirring speed, which gave 98.576% of degradation efficiency. The study of irradiation type effect shows that a solar irradiation gave higher yield than photocatalysis by UV lamp. The O2?- radicals were the principal active species responsible of the degradation of TRZ. The BOD5/COD ratio increased from 0.26 to 0.41 after 60 minutes of photocatalysis under solar light, indicating the feasibility of coupling the photocatalysis process to biological treatment for the removal of TRZ.

Photodegradation of New Methylene Blue N in Aqueous Solution Using Zinc Oxide and Titanium Dioxide as Catalyst

2012 ◽  
Author(s):  
Rusmidah Ali ◽  
Boon Siew Ooi
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Zinc Oxide ◽  
Titanium Dioxide ◽  
Optimum Condition ◽  
Metal Ion ◽  
Optimum Ratio ◽  
Photodegradation Rate ◽  
Uv Visible ◽  
Uv Lamp

Dalam kajian ini, ZnO dan TiO2 digunakan sebagai fotomangkin dalam pendegradasian pewarna New Methylene Blue N (NMBN). Kadar fotodegradasi diukur menggunakan alat spektrofotometer UV-Vis. Dalam kajian ini, New Methylene Blue N menunjukkan nilai serapan pada λ = 590 nm dan λ = 286 nm. Lampu UV (λ = 354 nm) digunakan dalam proses fotodegradasi. Dalam proses degradasi menggunakan ZnO menunjukkan 81.42% NMBN terdegradasi pada λ = 590 nm dan 77.75% pada λ = 286 nm. Sebaliknya, degradasi menggunakan TiO2 adalah 25.68% pada λ = 590 nm dan 26.37% pada λ = 286 nm. Peratus degradasi New Methylene Blue N ialah 88.89% dan 68.94% pada masing-masing λ = 590 nm dan λ = 286 nm apabila ditambahkan dengan H2O2. Campuran ZnO dan TiO2 dalam nisbah 85: 15 (0.085 g; 0.015 g) merupakan campuran fotomangkin yang paling optimum iaitu dengan peratus degradasi NMBN sebanyak 96.97% dan 93.61% pada λ = 590 nm dan λ = 286 nm. Penambahan ion logam Cu2+ memberikan peratus degradasi tertinggi berbanding ion logam lain iaitu 83.83% pada λ = 590 nm. Penambahan ion logam Pb2+ memberikan peratus degradasi tertinggi pada λ = 286 nm iaitu 81.25% pewarna terdegradasi. Keadaan optimum dicapai pada pH 5.90, dengan peratus degradasi tertinggi iaitu 92.84% dan 89.30% pada masing-masing λ = 590 nm dan λ = 286 nm. Kata kunci: New Methylene Blue N; fotodegradasi; larutan; ZnO; TiO2 In this study, ZnO and TiO2 are used as photocatalyst to degrade the dye, New Methylene Blue N (NMBN). The photodegradation rate was measured using UV-Visible spectrophotometer. In this study, New Methylene Blue N showed absorption values at λ = 590 nm and λ = 286 nm. UV lamp (λ = 354 nm) is used in the photodegradation process. Results showed that ZnO is a better photocatalyst compared to TiO2. The degradation by ZnO showed that 81% of NMBN was degraded at λ = 590 nm and 77.75% at λ = 286 nm. In contratst, the degradation using TiO2 was 25.68% at λ = 590 nm and 26.37% at λ = 286 nm. The percent degradation of New Methylene Blue N is 88.89% and 68.94% at λ = 590 nm and λ = 286 nm respectively when H2O2 was added. A mixture of ZnO and TiO2 in the ratio of 85: 15 (0.085 g: 0.015 g) is the most optimum ratio for the mixed photocatalyst where the degradation percentage of NMBN are 96.97% and 93.61% at λ = 590 nm and λ = 286 nm. The addition of Cu2+ metal ion gave the highest percentage of degradation (83.83% at λ = 590 nm) compared to other metal ions. The addition of Pb2+ gave the highest percentage of degradation at λ = 286 nm with 81.25% degradation of the dye. The optimum condition was achieved at pH 5.90, which gave the highest percentage degradation, 92.84% and 89.30% at λ = 590 nm and λ = 286 nm respectively. Key words: New Methylene Blue N; photodegradation; aqueous; ZnO; TiO2

scholarly journals Succinic acid in aqueous solution: connecting microscopic surface composition and macroscopic surface tension

2014 ◽  
Vol 16 (39) ◽  
pp. 21486-21495 ◽  
Author(s):  
Josephina Werner ◽  
Jan Julin ◽  
Maryam Dalirian ◽  
Nønne L. Prisle ◽  
Gunnar Öhrwall ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Surface Tension ◽  
Succinic Acid ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Md Simulations ◽  
Vapor Interface ◽  
X Ray ◽  
Ph Values ◽  
Microscopic Surface

The water–vapor interface of aqueous solutions of succinic acid, where pH values and bulk concentrations were varied, has been studied using surface sensitive X-ray photoelectron spectroscopy (XPS) and molecular dynamics (MD) simulations.

Instability waves on the air–sea interface

1993 ◽  
Vol 248 ◽  
pp. 363-381 ◽  
Author(s):  
G. H. Wheless ◽  
G. T. Csanady
Keyword(s):  
Surface Tension ◽  
Growth Rate ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Surface Velocity ◽  
Instability Waves ◽  
Interface Surface ◽  
Fluid Properties ◽  
Compound Matrix Method ◽  
Order Of Magnitude

We used a compound matrix method to integrate the Orr–Sommerfeld equation in an investigation of short instability waves (λ < 6 cm) on the coupled shear flow at the air–sea interface under suddenly imposed wind (a gust model). The method is robust and fast, so that the effects of external variables on growth rate could easily be explored. As expected from past theoretical studies, the growth rate proved sensitive to air and water viscosity, and to the curvature of the air velocity profile very close to the interface. Surface tension had less influence, growth rate increasing somewhat with decreasing surface tension. Maximum growth rate and minimum wave speed nearly coincided for some combinations of fluid properties, but not for others.The most important new finding is that, contrary to some past order of magnitude estimates made on theoretical grounds, the eigenfunctions at these short wavelengths are confined to a distance of the order of the viscous wave boundary-layer thickness from the interface. Correspondingly, the perturbation vorticity is high, the streamwise surface velocity perturbation in typical cases being five times the orbital velocity of free waves on an undisturbed water surface. The instability waves should therefore be thought of as fundamentally different flow structures from free waves: given their high vorticity, they are akin to incipient turbulent eddies. They may also be expected to break at a much lower steepness than free waves.

IMMOBILIZATION OF STRONTIUM FROM AN AQUEOUS SOLUTION USING THE CRYSTALLINE HYDROUS TITANIUM DIOXIDE FIBERS

1981 ◽  
Vol 10 (7) ◽  
pp. 957-960 ◽  
Author(s):  
Takayoshi Sasaki ◽  
Yu Komatsu ◽  
Yoshinori Fujiki
Keyword(s):  
Aqueous Solution ◽  
Titanium Dioxide ◽  
Titanium Dioxide Fibers
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