Iron Oxide Nanoflower–Based Screen Print Electrode for Enhancement Removal of Organic Dye Using Electrochemical Approach

In this study, for the first time, we developed a novel platform for the removal of the synthetic organic dye Reactive Blue 52 based on a screen-printed electrode (SPCE). Additionally, SPCE was supported on a nanocomposite obtained by decoration of reduced graphene oxide (RGO) with iron oxide nanoflowers (IONFs), labeled as IONF@RGO/SPCE. IONFs were synthesized by polyol-mediated reduction of iron (III) chloride and characterized. Nanocomposite was prepared using a microwave hydrothermal-assisted procedure. The high stability (service life) of the IONF@RGO/SPCE electrode was measured, and it remained almost unchanged over time, achieving the same removal efficiency after 50 cycles of usage. Electrical impedance spectroscopy (EIS) tests indicated the synergetic effect of the used IONF@RGO by reducing resistivity of the system and improving its catalytic activity, which was confirmed with cyclic voltammetry (CV tests) where the great increase of the electrochemically active surface area sites was obvious. The results clearly indicate that with this approach, the optimum removal time of the selected pollutant was only 30 min, at a working potential of 3 V and with potassium chloride as the supporting electrolyte, with color removal efficiency of 99%, while chemical oxygen demand (COD) of more than 40%, total organic carbon (TOC) decrease of around 20%, and biochemical oxygen demand (BOD5), i.e., biodegradability (BOD5/COD ratio) significantly increased were measured after only 1 h of the treatment. Overall, the electrochemical removal procedure proposed in this study could be a reliable novel system, opening a new approach to using screen print–based electrodes