pH-engineered TiO₂ nanoparticles with enhanced photocatalytic degradation of malachite green

This study examines how changing the pH engineering, as a green and simple strategy, morphological, optical, and photocatalytic properties of titanium dioxide nanoparticles (TiO₂). The Debye-Scherrer equation yields an average crystalline size of 13-16 nm at pH values of 2, 5, 9, and 12. The average particle size of TiO₂ nanoparticles measured by HR-TEM was 15 nm. The photocatalytic test requires adjusting several factors, including the time of the light exposure, the initial dye concentration, the pH, and the amount of catalyst used to break down the malachite green (MG). When exposed to visible light, the maximum malachite green dye removal rate (98.14%) is obtained with 100 ppm dye concentration, pH-12, and 0.05 g catalyst in 250 mL of malachite green dye solution over 240 min. The photostability and reusability of the synthesized photocatalyst are also tested.