Ag/TiNPS nanocatalyst: biosynthesis, characterization and photocatalytic activity

Abstract

Wastewater pollution by synthetic dyes has emerged as a serious environmental problem, causing a series of deleterious effects, since they have low biodegradability and considerable chemical stability, requiring advanced treatment technologies, such as Advanced Oxidative Processes (AOPs), such as heterogeneous photocatalysis. In this context, the present work aims to synthesize, characterize, and evaluate the photocatalytic activity of silver/titanium nanoparticles (Ag/TiNPs) using the biosynthesis method from Aloe vera extract for application in the removal of Rhodamine B dye (RhB) to propose an alternative to the problem of wastewater with dyes. Ag/TiNPs were characterized by N2 porosimetry (BET/BJ method), zeta potential (ZP), Field Emission Gun – Scanning Electron Microscope (FEG-SEM) and Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR). Ag/TiNPs showed SBET = 343 m2 g-1, Dp = 4.9 nm, Vp = 0.26 cm3 g-1, ZP = -15.1 mV and V-type isotherm with H1 hysteresis. ATR-FTIR showed the presence of characteristic functional groups of -OH, -C=O, -CH2, and -CH3. FEG-SEM micrographs presented a heterogeneous and porous surface with nanoparticle size around 12 nm. Regarding the heterogeneous photocatalysis, Ag/TiNPs showed 100% degradation of RhB (k = 0.0219 min-1) under visible irradiation after 120 minutes, with the possibility of reuse in 5 cycles and only 5% reduction in photocatalytic activity. Therefore, Ag/TiNPs showed promising characteristics for application as a nanocatalyst in the treatment of wastewater with dyes.