Preparation of carbon quantum dots/fly ash/steel slag particle electrodes and their performance in rhodamine B removal

Abstract Fly ash and steel slag are industrial wastes, and their resourceful treatment has been challenging. This study generated fly ash/steel slag particle electrodes (FA/SS PEs) using fly ash and steel slag as raw materials. Carbon quantum dots (CQDs) fabricated from semi-coke were then loaded onto their surface to produce CQDs/FA/SS PEs. The samples were characterized by SEM, nitrogen adsorption, XRD, and electrochemical measurements. The results show that FA/SS PEs present a favorable electrocatalytic performance for rhodamine B (RhB) in the three-dimensional reaction system owing to their rich pore structures and an active component (Fe 2 O 3 ), the other metal oxides in FA and SS become the backbone of FA/SS PEs during the preparation process. CQDs could promote the electrocatalytic performance of the FA/SS PEs due to their defect-rich surface and high specific surface area. The RhB degradation rate over CQDs/FA/SS PEs increased by approximately 10% compared to that over FA/SS PEs at a reaction time of 60 min, and it could reach 100% at pH 2 and a reaction time of 45 min over CQDs/FA/SS PEs. The RhB degradation process mainly involves a three-dimensional electrochemical-Fenton process over CQDs/FA/SS PEs, and CQDs/FA/SS PEs act as both the particle electrode of the three-dimensional reaction system and the catalyst for Fenton oxidation.