Comparison of H2O2/UV and Heterogeneous Photocatalytic Processes for the Degradation of Dichloroacetic Acid In Water

AbstractThe importance of discovering the true catalytically active species involved in photocatalytic systems allows for a better and more general understanding of photocatalytic processes, which eventually may help to improve their efficiency. Bi2O3 has been used as a heterogeneous photocatalyst and is able to catalyze several synthetically important visible-light-driven organic transformations. However, insight into the operative catalyst involved in the photocatalytic process is hitherto missing. Herein, we show through a combination of theoretical and experimental studies that the perceived heterogeneous photocatalysis with Bi2O3 in the presence of alkyl bromides involves a homogeneous BinBrm species, which is the true photocatalyst operative in the reaction. Hence, Bi2O3 can be regarded as a precatalyst which is slowly converted in an active homogeneous photocatalyst. This work can also be of importance to mechanistic studies involving other semiconductor-based photocatalytic processes.

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Glossary of terms used in photocatalysis and radiation catalysis (IUPAC Recommendations 2011)

Pure and Applied Chemistry ◽

10.1351/pac-rec-09-09-36 ◽

2011 ◽

Vol 83 (4) ◽

pp. 931-1014 ◽

Cited By ~ 185

Author(s):

Silvia E. Braslavsky ◽

André M. Braun ◽

Alberto E. Cassano ◽

Alexei V. Emeline ◽

Marta I. Litter ◽

...

Keyword(s):

Electromagnetic Radiation ◽

Fast Moving ◽

Quantitative Description ◽

Radiation Chemistry ◽

Industrial Applications ◽

Clear Distinction ◽

Photocatalytic Processes ◽

Up Scaling

This glossary of terms covers phenomena considered under the very wide terms photocatalysis and radiation catalysis. A clear distinction is made between phenomena related to either photochemistry and photocatalysis or radiation chemistry and radiation catalysis. The term “radiation” is used here as embracing electromagnetic radiation of all wavelengths, but in general excluding fast-moving particles. Consistent definitions are given of terms in the areas mentioned above, as well as definitions of the most important parameters used for the quantitative description of the phenomena. Terms related to the up-scaling of photocatalytic processes for industrial applications have been included. This Glossary should be used together with the Glossary of terms used in photochemistry, 3rd edition, IUPAC Recommendations 2006: (doi:10.1351/pac200779030293) as well as with the IUPAC Compendium of Chemical Terminology, 2nd ed. (the “Gold Book”, 2006– doi:10.1351/goldbook) because many terms used in photocatalysis are defined in these documents.

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Photocatalysis of Coomassie Brilliant Blue Using Clay Mineral

Materials Science Forum ◽

10.4028/www.scientific.net/msf.869.765 ◽

2016 ◽

Vol 869 ◽

pp. 765-767 ◽

Cited By ~ 3

Author(s):

Layane Rodrigues Almeida ◽

João Sammy Nery Souza ◽

Edson Cavalcanti Silva Filho ◽

Josy Anteveli Osajima

Keyword(s):

Organic Pollutants ◽

Uv Light ◽

Brilliant Blue ◽

Blue Dye ◽

Secondary Treatment ◽

Toxic Compounds ◽

Coomassie Brilliant Blue ◽

Kinetics Of ◽

Coomassie Brilliant ◽

Photocatalytic Processes

The presence of organic pollutants, which cannot be eliminated by conventional processes of primary and secondary treatment, can be problematic. Photocatalytic processes offer an efficient breakdown of organic pollutants into non-toxic compounds such as CO2 and H2O. This paper proposes the use of the titanium dioxide embedded in palygorskite as a photoactive material in the degradation of cationic dye, Coomassie Brilliant Blue. The system was irradiated using UV light for a maximum time of 120 minutes. The concentration of the dye used was 1.0x10-4 mol L-1 in 0.5 g L-1 of the photoactive material. The kinetics of the system was monitored by UV-Vis spectrophotometry. In 120 minutes of radiation, the process of photocatalysis reduced the initial concentration of the Coomassie Brilliant Blue dye in half.

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