Turbidimetric method for evaluation of photocatalytic activities of suspended fine particles

Abstract

A spectrophotometer with special cuvette was developed for evaluating the photocatalytic activities of suspended fine particles. The spectrophotometer can continuously irradiate UV light using LED to the sample solution, and changes in the absorbance at 664 nm during photocatalytic degradation of methylene blue (MB) were monitored continuously. From the onset of MB degradation, the absorbance decreased and reached a steady value at the end of the reaction. This process was expressed by first order kinetics and the photocatalytic activities of various fine particles could be evaluated quantitatively based on the reaction rate constant (k). The effect of photocatalysis using various TiO₂ fine particles on the physiological activities of Euglena gracilis was related with k value.

Keywords:

• photocatalyst
• fine nano sized particles
• specialized spectrophotometer
• Euglena gracilis
• rate constant

Acknowledgments

This study was supported in part by a Grant-in-Aid for Exploratory Research (nr 20651006) from the Japan Society for the Promotion of Science (JSPS).

Disclosure

The authors report no conflicts of interest in relation to this paper.