PREPARATION OF ELECTRODELESS

            DISCHARGE LAMPS

Staff:

Vladimír Církva, Stanislav Relich, Hana Žabová, Leona Vlková

Co-workers:

Milan Hájek

External co-workers:

Petr Klán (Masaryk University in Brno, Department of Organic chemistry)
 

 

 

Financing, funding:

GACR (104/06/0992) Preparation of the electrodeless discharge lamps for photochemical applications

 

          The project is concerning on preparation of the electrodeless discharge lamps (EDLs) as suitable source of UV/VIS light for photochemical reactions. The EDL consists of a glass tube filled under a lower pressure with an inert gas and an excitable (filling) substance, i.e. mercury or other element, and generates UV/VIS radiation when placed into the microwave field. The utilization of other filling materials than mercury (i.e. sulfur) will be practical, new, original and environmental-safety in the EDL performance, according to our preliminary research. The effect of operating EDL parameters (i.e. mass and chemical form of the filling material, nature and pressure of filling gas), the microwave power output and medium properties (i.e. transmittance, polarity, boiling point) on spectral characteristics (relative intensity vs. wavelength) will be studied. The prepared EDLs with suitable operating parameters and spectral characteristics will be applied for selected photochemical (cis-trans photoisomerization of stilbene derivates) and photocatalytical (titanium oxide) reactions, according to the required absorption output. The results of the project will be exploitable in the synthetic organic photochemistry as well as in environmental applications (i.e. photodegradation of the persistent organic pollutants, PCB, PCP, PCDD/PCDF).

 

 

What is the electrodeless discharge lamp (EDL)?

 

     Electrodeless discharge lamp (EDL) consist of a glass envelope (Pyrex, quartz) filled with an noble gas (argon) under a low pressure and filling material (Hg, Cd, P, I2, S, Se). Microwave field can trigger gas discharge causing the emission of UV/VIS radiation.

more ...

 

 

Preparation of electrodeless discharge lamps

 

     The lab preparation of EDLs was elaborated and the method was publicated [8], the scheme of apparatus.

 

 

 

Solved problematics:

 

Effect of operating parameters on EDL output

 

Measurement of EDL spectral characteristic

 

Evaluation of EDL output

 

 

Publications:

[1] Klán, P.; Církva, V.: Microwave Photochemistry. In Microwaves in Organic Synthesis, Chap. 14, (Loupy, A., Ed.), pp. 463-486, John Wiley, Weinheim 2002.

[2] Církva, V.; Kurfürstová, J.; Hájek, M.: Chem. Listy 96 (2002) 939. Fotochemie v mikrovlnné troubě. (Photochemistry in microwave oven)

[3] Müler, P.; Klán, P.; Církva, V.: J. Photochem. Photobiol. A 158 (2003) 1-5. The electrodeless discharge lamp: a prospective tool for photochemistry. Part 4: Temperature- and envelope material-dependent emission characteristics.

[4] Müler, P.; Klán, P.; Církva, V.: J. Photochem. Photobiol. A 171 (2005) 51-57. The electrodeless discharge lamp: a prospective tool for photochemistry. Part 5: Fill material-dependent emission characteristics.

[5] Církva V.: Microwave Photochemistry. 1st Avogadro Symposium Quo Vadis Chemistry ?, Sorisole, Italy, 9-11 September 2005.

[6] Církva V., Relich S., Vlková L., Hájek M.: Microwave Photochemistry: Preparation of the Electrodeless Discharge Lamps and their Photochemical Applications. 10th International Conference on Microwave and High Frequency Heating, Proceedings Book, p. 183-186, Modena, Italy, 12-15 September 2005.

[7] Církva V., Relich S., Vlková L., Hájek M.: Microwave Photochemistry: Preparation of the Electrodeless Discharge Lamps and their Photochemical Applications. 40th Conference Pokroky v organické, bioorganické a farmaceutické chemii, Chem. Listy 99(11), 864, 2005], Nymburk, Czech Republic, 18-20 November 2005.

[8] Církva, V.; Vlková, L.; Relich, S.; Hájek, M.: J. Photochem. Photobiol. A 179 (2006) 229-233. Microwave photochemistry IV. Preparation of the electrodeless discharge lamps for photochemical applications.

[9] Klán, P., Církva, V.: Microwaves in Photochemistry. In: Microwaves in Organic Synthesis. (Loupy, A., Ed.), pp. 860-897, WILEY-VCH Verlag, Weinheim, 2006 (ISBN 3-527-31452-0).

[10] Církva, V.: Photochemistry in the Microwave Oven. 3rd International Conference on Microwave Chemistry, Book of Abstracts, p. OC-4, Brno, Czech Republic, 03-07 September 2006.

[11] Relich, S., Církva, V., Vlková, L., Hájek, M.: Photochemistry in the Microwave Oven: Preparation, Evaluation and Applications of the Electrodeless Discharge Lamps. 3rd International Conference on Microwave Chemistry, Book of Abstracts, p. PO-21, Brno, Czech Republic, 03-07 September 2006.

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