Non-piezoelctric SiO2 amorphous nanomaterials for highly tribocatalytic water purification

Abstract

Being widely available in the rock layers of the earth, SiO2 is among the earth's most thoroughly distributed natural mineral resources. Here, the non-piezoelectric amorphous SiO2 mineral nanoparticles have been experimentally designed for the efficiently tribocatalytic dye degradation under mechanical friction provided by the 400~1200 rpm low-velocity stirring. The friction between the catalysts’ surface and the stirring rod leads to the generation of these positive and negative charges to respectively react with the hydroxide and oxygen in the dye solution to produce some active substances, yielding to tribocatalytic organic dye degradation. After being mechanically stirred at 1000 rpm for 6 h using amorphous SiO2 mineral nanoparticle catalysts, ~95.2% Rhodamine B dye can be obviously degraded. These radical trapping experiments show that ·OH and ·O2- are the main active substances. Furthermore, increasing the contact area or the friction contact interface's roughness is helpful for enhancing the tribocatalytic performance. After 3 recycling cycles, the SiO2 nanoparticles can still degrade ~89.2% RhB dye. The low-cost SiO2 mineral nanoparticles, with these advantages of being widely distributed, are potential to harvest environmental common mechanical friction energy for the application of organic pollution degradation.