Preparation and characterization of novel SnO2-GO/TiO2NTs electrode for the degradation of electroplating effluents

Abstract

A novel SnO2-loaded GO/TiO2NTs (nanotubes) electrode was synthesized by an anodization method for the electrochemical oxidation (EO) of heavy metals in the synthetic electroplating solution to improve the electrode's stability. The electrode morphology, structure, and characteristics were characterized with various spectroscopic and microscopic approaches to confirm the synthesis of the intended nanotube electrode material. The successful electrochemical deposition of GO on the TiO2 plate and subsequent SnO2 loading on the GO/TiO2NTs electrode was observed by FESEM analysis. EDS analysis confirmed that 3.76%wt of tin (Sn) nanoparticles were formed over the GO/TiO2 substrate. The crystallite size of SnO2-loaded GO/TiO2NTs, i.e., 16.90 nm, was confirmed by XRD analysis. For the first time, the performance of SnO2-loaded GO/TiO2NTs electrode was tested for the reduction of the aqueous solution, containing chromium (Cr)(VI), zinc (Zn), and citric acid (CA) as model pollutants. The effect of operating parameters like solution pH and current density (j) on degradation efficacy was studied. EO using SnO2-loaded GO/TiO2NTs led to > 98% degradation of heavy metal ions and > 88% degradation of chemical oxygen demand (COD) after 130 min of oxidation under optimized conditions (50.16 mA/cm2 current and pH 4). Furthermore, a reusability study of the synthesized electrode has also been conducted. The electrodes were durable enough to be used even after thirty cycles. Hence, this study demonstrates that combining titanium dioxide (TiO2) and graphene oxide (GO) embellished with tin oxide (SnO2) nanoparticles can be an efficient and cost-effective electrode for removing electroplating effluents.