Synthesis of silver decorated silica nanoparticles with rough surfaces as adsorbent and catalyst for methylene blue removal

The discharge of dyes from industries to water reservoirs has attracted extensive attention worldwide, and it is of great importance to remove them efficiently. In this study, a series of silica nanoparticles with rough surfaces was prepared, and highly dispersed silver nanoparticles were loaded on its surface through a simple wet-impregnation method. The adsorption performance and catalytic activity of the as-prepared Ag/SiO2 for methylene blue (MB) removal was investigated. The results demonstrated that the Ag/SiO2 with smaller particle size and higher Ag loading amount shows high adsorption capacity and catalytic activity for MB. The maximum adsorption capacity was found to be ~55 mg/g, which is more than two times of pure silica nanoparticles. Besides, MB could be degraded by more than 99% of the initial concertation (40 mg/L) within 3 min and rate constant of the catalytic reduction achieved as high as 2.128 min−1. Moreover, the as-prepared Ag/SiO2 shows good stability in acidic environment and excellent reusability for at least eight successive cycles of adsorption and four cycles of catalytic reduction.