The Synergistic Effect of Nitroprusside and CuNiDH as Electrocatalyst with High Performance for Electro-Oxidation of Sodium Sulfide in Alkaline Media

Due to the importance of sulfide removal from wastewater and waste streams, in this study, eight cost-effective electrocatalysts were designed and prepared by electrochemical technique and their performance was evaluated in the presence of a high concentration of sodium sulfide. According to the results, among the prepared electrocatalysts, CuNiDH-NP@G electrode (modified graphite with nitroprusside (vasodilator drug) and CuNi-double hydroxide) had the highest efficiency in sulfide electro-oxidation. Then, to improve the performance of the CuNiDH-NP@G electrode its structure was optimized and investigated by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS). Based on the results of electrochemical analyzes, in the presence of sulfide the process is controlled by diffusion. The diffusion coefficient, heterogeneous electron transfer rate constant and electron transfer coefficient for sulfide electrochemical oxidation were determined 2.85 × 10-5 cm2/s, 3.126 cm.s-1 and  0. 72 respectively. The use of non_noble metals as the electrocatalyst for sulfide electro-oxidation, the very easy, affordable, and fast preparation of the introduced electrode and high performance of it demonstrate important items for the use of this procedure and electrode in the subsequent investigation of a different material.