Regulable surface hydroxyl group content in disperse ultrafine amorphous SiO2 nanoparticles

Abstract

AbstractAmorphous silica (SiO2) nanoparticles (NPs) can be applied in environmental pollutant remediation, element removal, and water purification. The content of surface silanol groups in amorphous SiO2 NPs affects the characteristics of SiO2 NPs. However, the regulation of surface silanol group content in amorphous SiO2 NPs below 10 nm remains a challenge. Herein, tunable surface silanol group content was achieved in disperse ultrafine amorphous SiO2 NPs by controlling calcination and rehydroxylation. The surface silanol group content in amorphous SiO2 NPs is low (10 nm) and can be tuned from 0% to 2.5%. The amount of naphthalene adsorbed by the SiO2 NPs increases with increasing surface silanol group content. The surface silanol group content in SiO2 NPs can be an effective means to tune their adsorption performance and applications.