Authors : Bhishma Karki, Jeevan Jyoti Nakarmi and Mukesh Jerambhai Keshavani
Abstract: Water treatment scheme is proposed where two variables are taken. BiVO4 photoanode combined with a thin film silicon solar cell. It has a band gap energy of 2.4 eV which has good catalytic properties for the degradation of phenol and chloroform. Applying an external bias voltage in order to reach the required potentials for pollutant degradation. To cover the voltage needs, an a-Si:H/nc-Si:H solar cell was coupled with the BiVO4. This solar cell was specifically designed to work under the transmitted spectrum of the BiVO4 with thicknesses of 200 and 1000 nm for the top and bottom cell, respectively. This device has successfully been fabricated and tested for removal of organic contaminants from an aqueous solution. The device with the solar cell performed better than, the BiVO4 photoanode alone with a similar external bias voltage applied, suggesting that the solar cell does not only act as a voltage source but also as a current source. To compare the performance of this device to the commercially available ZnO photoanode illuminated by UV light, an energy balance for phenol removal was performed. The energy needed for phenol removal was reduced from 1.83 Wh/mg with the ZnO/UV device to 0.79 Wh/mg with the BiVO4 with a solar cell indicating the potential of the proposed device to improve the water treatment of organic pollutants by using Earth-abundant materials and solar energy.
Bhishma Karki, Jeevan Jyoti Nakarmi and Mukesh Jerambhai Keshavani, 2019. Water Purification from Organic Pollutants using a Photo-Oxidation. Research Journal of Applied Sciences, 14: 192-197.