Development of Three-Dimensional Electrodes Based on Biochar and Their Application in Wastewater Treatment

1,4-Dioxane is a toxic and harmful refractory organic pollutant. If the sewage containing 1,4-dioxane is not treated properly, it will cause environmental pollution and endanger human health. In this experiment, corncob and sodium alginate were used as biochar carriers, and Fe and Ce were loaded to prepare a gel spherical particle electrode, which was applied to the three-dimensional (3D) electrochemical system. The wastewater was simulated with 100 mg/L 1,4-dioxane solution, and the effects of different electrochemical systems, voltage, pH value, electrolyte concentration and other factors on the degradation efficiency were studied. The best treatment conditions of 1,4-dioxane solution are as follows: Voltage 18 V, pH = 5, electrolyte concentration 0.15 mol/L, particle dosage 50 g/L, and the removal rate can reach 62.14%. Compared with the removal rate of 15.82% in a simple two-dimensional (2D) electrochemical system, the effect is obviously improved, and the material has good repeatability, which is suitable for engineering applications. The results of scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) show that both Fe and Ce elements are loaded on the modified Fe3O4/CCBC@SA/Ce gel sphere, and the morphology retains the structural characteristics of the original SA gel sphere. The surface presents irregular folds, collapses and pores, and the interior presents a typical porous sheet structure. This structure enables the material to obtain higher conductivity and adsorption.