Applications of TiO₂–CeO₂/bamboo-biochar particle electrodes to enhanced treatment of phenol wastewater in a three-dimensional electrochemical reactors

Phenolic compounds in wastewater are highly biotoxic and harmful to the environment and human health. Due to the shortcomings of traditional treatment methods, the three-dimensional electrochemical reactors (3DERs) have been widely studied in phenol wastewater treatment due to their high efficiency, simple operation and low chemical addition. Particle electrodes are crucial, and TiO₂-modified particle electrodes have been shown to contribute to the oxidation of pollutants. The TiO₂–CeO₂ modified bamboo biochar particle electrodes (BCPEs) were newly prepared by sol–gel and calcination two-step method, and their surface microscopic morphologies, crystal structures, physical and chemical properties were determined by characterization. Electrochemical experiments showed that the mass transfer rate (ν = 15.47 × 10^–3) and the electrochemically active surface area (ECSA) of TiO₂–CeO₂ modified BCPEs were larger than that of TiO₂/BC and BCPEs. Optimal electrolysis conditions were obtained by the corresponding surface model: the Ti/Ce molar ratio of 10, current density (j) of 32 mA/cm², the initial phenol concentration of 100 mg L⁻¹, and the phenol removal reached 83.02%. After 120 min electrolysis of phenol wastewater with an initial concentration of 100 mg L⁻¹ at j = 30 mA/cm² in the 3DERs, the phenol removal reached 81.69%. The experimental results showed that the TO₂–CeO₂ modified BCPEs realized the efficient treatment of phenol wastewater in the 3DERs. This study provides theoretical and technical support for the application of three-dimensional electrodes to the advanced treatment of phenol wastewater.