Polyacrylonitrile-Based Carbon Fiber as Anode for Manganese Electrowinning: Anode Slime Emission Reduction and Metal Dendrite Control

Abstract

The traditional lead-based anodes used in industrial electrolysis process trigger the high energy consumption, lead pollution and hazardous anode slime discharge. In this work, an original undecorated Polyacrylonitrile (PAN)-based carbon fiber was employed as anode material (CF anode) to evaluate its electrochemical performance and feasibility, aiming at fundamentally reducing the energy consumption and pollution emissions for the manganese electrolysis. The results shown that the CF anode exhibited excellent electrocatalytic activity and delivered a current density of 350 A m–2 at an overpotential decreased by 112 mV for oxygen evolution reaction (OER) compared with commercial lead-based alloy anode (Pb anode). We also found CF anode exhibited favorable performance with average current efficiency increased by 4.30%, energy consumption decreased by 8.36%, and a noteworthy abatement of anode slime by 80% compared with Pb anode in MnSO4 electrolyte. Additionally, the growth of manganese dendrites on the cathode edge which directly affected the electrolytic efficiency has also been effectively controlled and the possible mechanisms were also discussed. This work displayed the excellent electrocatalytic effect of CF anode serviced as a promising candidate for green and efficient electrolysis process.