Rapid Synthesis of Silver Nanoparticles and Their Decoration on TiO2 by Plasma-Over-Liquid Process: Characterization and Application for Tetracycline Antibiotic Degradation

Authors

• Margarita Skiba * ¹
• Victoria Vorobyova ²

1. Department of Inorganic Materials Technology and Ecology, Ukrainian State University of Chemical Technology, Ukrine
2. Department of Physical Chemistry, National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", Kyiv, Ukrine

Abstract

The results of studies on obtaining and characterization of silver nanoparticles aqueous solution under the action of the contact non-equilibrium low-temperature plasma and stabilizing agent (sodium citrate) are presented in the paper. The influence of the basic parameters on the synthesis of silver nanoparticles was studied. Different physicochemical characteristics were investigated: initial precursor concentration, reagent ratio, duration of plasma discharge treatment. [Ag⁺]:[Cit] ratio as 1:1 at silver ion concentrations of Ag⁺ 0.1-3.0 mmol/L and treatment of the reaction system for 4-5 minutes was found to be appropriate. Under these conditions, the surface plasmon resonance (SPR) was observed at 405-420 nm on UV-Vis spectra. Particles with the average diameter of 35.0 ± 2.0 nm, spherical shape and polydispersity index of 0.032 ± 0.01 are typical amongst synthesized nanoparticles at [1]:[1] molar ratio. It was found that the reaction of nanoparticle dispersion formation was a pseudo-first order reaction with the reaction rate constant of 0.61 min^-1. It has been established that sodium citrate is the capping agent and acts only as the stabilizer of Ag NPs. To prepare the nanocomposite material (TiO₂/Ag NPs), silver nanoparticles have been deposited on photocatalyst (TiO₂ rutile phase) by plasma discharge. EDS and SEM analysis showed that composite material has core–shell structure including Ag nanoparticles (NPs) shell with size of 15-25 nm. The results indicated that TiO₂/Ag exhibited good photoactivity under ultraviolet radiation. It was found that 98.7% of tetracycline was decomposed at photocatalyst TiO₂/Ag NPs under the light irradiation. The experimental data of photochemical decomposition of tetracycline under the light irradiation at 430 nm showed that reaction is described by the pseudo first order kinetic model with rate constant (k value) of (3.6)×10⁻³ min⁻¹.

Keywords

• Silver nanoparticles
• Citrate
• Plasma-liquid phase
• Photocatalys. Tetracycline
• Degradation
• Titanium dioxide