Improving Photobioreactor wall Using Optical Brightener: Investigating the Photostability of Coated Layer and Algal Growth

In this work, photostability, absorption and emission intensity of coated polycarbonate (PC) sheets with optical brightener (OB) as a wavelength converter material have been investigated. In addition, this coated sheet was used as a wall for microalgae culture flask, as a small scale photobioreactor, for studying the spectral conversion of UV-A radiation to blue light region and its effect on the biomas productivity of microalga Chlorella sp. For this purpose, the PC sheets coated by different concentrations of OB dissolved in thermoplastic acrylic resin were prepared and placed between the UV-A radiation source and the culture flasks. Results showed that the photostability increases under UV-A and solar radiation by applying two coating systems. Also, higher surface concentration causes an increase in emission intensity of coated sheet. Furthermore, compared with the uncoated sheets, the sheet coated with OB layer exhibited up to 70% higher biomass production of microalga Chlorella sp.