Study of phytotoxicity, remarkable photocatalytic activity, recycling process and energy consumption cost of TiO 2 quantum dots photocatalyst for photodegradation of Coomassie brilliant blue R dye

The phytotoxicity experimental assessment revealed that the water used in the germination of Lycopersicon esculentum tomato seeds which was treated with TiO 2 quantum dots, TDs1 (2.7 nm), TDs2 (3.1 nm) and TiO 2 (Degussa) respectively, had no impact on the germination process. TiO 2 quantum dots with a high BET Specific surface area of 462.3 m 2 /g for TDs1 (2.7 nm) and 338.22 m 2 /g for TDs2 (3.1 nm) were synthesized through the sol-gel method using TiCl 4 in different polar solvents. The structure, shape, and size of the prepared TDs samples have been characterized by techniques such as XRD, FE-SEM, HRTEM, and EDX, confirming no additional phases or impurities in TDs. The optical band gaps of TDs samples were determined from their diffuse reflectance spectral data using Kubelka-Munk Equation. Photocatalytic activities of 91 and 89% were achieved in the mineralization of Coomassie brilliant blue R (CBBR), a model commercial dye, under direct sunlight and xenon lamp irradiation, respectively. The reactive species on the photodegradation mechanism for the TDs prepared samples were determined by different trapping agents. The photocatalytic activity of the TDs samples remained strong after eight repetitions with a Xenon photoreactor and direct solar light. The assessment of the photodegradation efficiency of CBBR dye in terms of its beneficial influence on energy consumption (E E/O ) and price estimates has been reported.