An electrodeposition of Cu-MOF on platinum electrode for efficient electrochemical degradation of tartrazine dye with parameter control and degradation mechanisms: Experimental and theoretical findings

Abstract

Electrochemical oxidation is a low-toxicity, fast-reacting technology that is easy to employ. This technology has great promise for improving the sustainability and efficiency of wastewater treatment by eliminating dyes and other organic contaminants. In this study, a cathodic electrodeposition technique was used to effectively synthesize pure Cu-MOF on a Pt electrode. Fourier-Transform Infrared Spectroscopy (FTIR), Ultraviolet -Visible Spectroscopy (UV-Vis), Scanning Electron Microscopy (SEM), Energy-Dispersive X-Ray (EDX), and X-Ray Diffraction (XRD) were used to evaluate the synthesized Copper-Metal Organic Framework (Cu-MOF). The electrochemical degradation of tartrazine dye in an aqueous KCl solution under various conditions was used to evaluate the electrochemical efficiency of the Cu-MOF/Pt electrode. Tartrazine (Tz) degradation as a function of time has been adjusted for the influence of operational parameters such as the type of supporting electrolyte, pH of the solution, accumulation time, and applied potential. Based on the results, the acid medium (pH=3) was the most beneficial medium for the active degradation of Tz dye at optimal operating conditions. It was found that 99 % of the dye had disappeared following 20 min of electrolysis. The optimal potential for the degradation of Tz was 1.4 V of the applied potential since it has no negative impacts on the energy consumption or stability and durability of the electrodes. The Tz degradation was fitted to pseudo-first-order kinetics with a rate constant of 0.124 min-1. The findings demonstrated that Cu-MOF/Pt has a good electrochemical efficiency of 99 %, and the electrode recovery, reproducibility, and reusability have all been researched. A computational investigation used the Lee/Yang/Parr (B3LYP) level, 6-311++ G(d,p), as the basis for function set calculation to demonstrate the electrochemical destruction of Tz by the HClO radical. The results showed that the experimentally predicted mechanism and the theoretically determined mechanism agreed remarkably well. According to the proposed mechanism, Cu-MOF functions as a catalyst in the degradation of Tz, where it discharges water to produce HO• radicals, which are physically adsorbed on the Cu-MOF/Pt surface. Cu-MOF(HO•) combines with Cl− ions presence in water to form Cu-MOF(HClO) which attacks Tz dye in the azo bond (–N=N–) and degrades it into CO2 and H2O.

Keywords

• Electrochemical degradation
• Cu-MOF
• Tartrazine dye
• Chronoamperometry
• DFT calculation