Electro-dissolution of metal scrap anodes for nickel ion removal from metal finishing effluent

Abstract

This contribution reports a novel and cost efficient strategy for nickel ion removal from metal finishing effluents by electro-dissolution of scrap aluminium and iron sacrificial anodes. Electro-coagulation of effluent was carried out at 30 mA/cm 2 current density for 60 min. The nickel ion concentration of electroplating effluent was analysed by Atomic Absorption Spectroscopy. SEM images of iron and aluminium scrap anodes were critically analysed. Parameters such as heavy metal removal, anode dissolution rate with respect to heavy metal removal, reaction kinetics and cost estimation have been elaborately studied. Electro-coagulation at 30 mA/cm 2 for 60 min using iron and aluminium scrap anodes resulted in 95.9 and 94.1 % nickel ion reduction, respectively, with 0.0094 and 0.0053 g/ppm dissolution rates. The energy consumption for scrap aluminium and iron anodes was 0.0547 kWh/L. Loose internal bonding and spongy surface morphology of used metal scrap render high porosity and active surface area, enhancing reaction rate. Low cost and ready availability of waste scrap makes the process of electro-coagulation economically viable. Thus, the findings from this contribution point decisively at the superiority of waste metal scrap-based anodes for economic and environmentally sustainable heavy metal ion removal from metal finishing effluent.

Removal of arsenic in groundwater from western Anatolia, Turkey using an electrocoagulation reactor with different types of iron anodes

“…Since sacrificial metal anodes in the EC process are usually used of iron and aluminum plates, these electrodes have a relatively low surface area and high manufacturing costs, making EC technology economically impractical. On the other hand, the waste-scrap electrodes have a larger surface area than the other two-dimensional electrodes, thus presenting a significant contact are between the contaminants and anodes in EC reactor, enhancing the practical application of EC process owing to its low cost ( Vignesh et al., 2017 ; Elazzouzi et al., 2021 ). Moreover, even the available literature studies on arsenic removal by EC process using a plate, ball, and scrap electrodes are generally synthetically prepared As solutions, and very limited studies with real As-contaminated groundwater samples have been performed ( Kobya et al., 2015 , 2017 ; Amrose et al., 2013 ; Garcia-Lara and Montero-Ocampo, 2010 ).…”