Nanocrystalline FeNi alloy powder prepared by electrolytic synthesis; characterization and its high efficiency in removing Remazol Red dye from aqueous solution

Abstract

The electrodeposition technique used for the preparation of nanostructure powder looks to be advantageous since it is simple, quick to apply, inexpensive, works at room temperature, and enables chemical structure prediction. The galvanostatic electrochemical synthesis of ncFeNi alloy powder from an aqueous sulphate solution containing NO3􀀀 ions is successfully achieved. The effect of operating conditions, like current density, pH, temperature, and NO3􀀀 anion concentrations on the electrodeposition process was investigated. EDX analysis showed a wide range of Fe content in the ncFeNi powder, it was ranging from 47 to 71% depending on the operating conditions and the Fe2+/Ni2+ ratio. For example, the Fe content in the powder alloy increase with increasing the applied current density or decreasing the bath temperature. At all ratios of [Fe2+]/[Ni2+] in the bath, the Fe content is permanently greater than Ni content indicating anomalous codeposition. Powdered ncFeNi alloy synthesized at current densities and overpotentials around the limiting diffusion current density plateau and/or at greater, where the concurrent H2 evolution reaction takes place. The presence of NO3􀀀 ions enhance the appearance of diffusion current. Instantaneous nucleation accompanied by 3D growth under charge transfer control has characterized the deposit of ncFeNi powder. The powder is a crystalline phase of FeNi3. TEM analysis of the resulting ncFeNi discovered a particle size average of 12.11 nm. The greater the concentration of Fe in the bath the high the decrease in coercivity and the higher the saturation magnetization. On the other hand, the ncFeNi powder is used as an efficient adsorbent for Remazol Red dye (RRD) removal. Moreover, the powder obtained from bath 1 exhibited higher removal efficiency than that obtained from bath 3 owing to its larger pore volume and surface area. The adsorption kinetics followed Freundlich isotherm and were well suited to the pseudo-second-order model.