Ball milling assisted mechano-catalytic dye degradation using SrTiO3 nanoparticles†

Abstract

Ball milling stands as a versatile and widely used technique that involves the mechanical grinding of solid materials via ball mills. Conventionally employed for synthesizing nanomaterials and complex compounds, this method has now been harnessed directly for catalysis due to its capability for surface charge separation. Herein, in the present study, we have explored the potential of ball milling to activate material with low piezoelectric coefficient for catalysis by demonstrating the ball-milling-induced mechano-catalytic activity of SrTiO₃ (STO) nanoparticles for the degradation of toxic methylene blue (MB) dye. With the assistance of ball milling, STO nanoparticles (of 0.3 g dosage) were found capable of degrading 70% of 10 ppm MB dye at 400 rpm speed with 10 Zr balls in just 1 hour. A series of parametric studies were performed to analyze the effect of various process conditions, like catalyst dosage, initial concentration of dye, ball milling speed, and number of milling balls. Further, scavenging tests were carried out to detect the responsible reactive species for dye degradation. Moreover, the present ball milling process was compared with the trivial ultrasonication method where STO showed just 12% degradation in 1 hour. The results manifest the superiority of ball milling catalysis which not only offers precise control over reaction parameters but also encompasses scalability, simplicity, and better potential to conduct catalysis under environmentally benign conditions.