Preparation of Tin–Antimony anode modified with carbon nanotubes for electrochemical treatment of coking wastewater

Abstract

To improve the electrocatalytic activity, carbon nanotubes (CNTs) were used to modify a titanium-supported tin–antimony anode (Ti/SnO2–Sb). Compared to a Ti/SnO2–Sb anode, the Ti/SnO2–Sb-CNTs anode exhibited a higher oxygen evolution potential (1.62 V), smaller crystalline volume (71.23 Å3), larger active surface area (0.371 mC cm−2), lower charge transfer resistance (8.24 Ω), and longer service life (291 h). The CNTs provided the Ti/SnO2–Sb anode with effective electrocatalytic activity, conductivity and stability. To evaluate its performance, the Ti/SnO2–Sb-CNTs anode was utilized for the treatment of coking wastewater. The chemical oxygen demand (COD) and total organic carbon (TOC) removal yields of the coking wastewater reached 83.05% and 74.56% under the optimal current density of 25 mA m−2, Na2SO4 concentration of 35 mM, and plate spacing of 10 mm. UV254, ultraviolet–visible absorption spectroscopy, excitation–emission matrix spectra spectroscopy, and Fourier-transform infrared spectroscopy analyses showed that the aromatic and nitrogenous compounds in the coking wastewater were degraded. Furthermore, the electrochemical treatment could effectively reduce the toxicity of the coking wastewater. The energy consumption of the coking wastewater treatment was reduced to 396.56 kWh (kg COD)−1. This study provides a basis engineering application of the electrochemical oxidation of coking wastewater.