RESUMO
This study investigates a combined photocatalytic and adsorption system to maximize the removal of 1,4 dioxane from hazardous landfill leachate (HLL). The production of transformation products was also investigated to obtain a comprehensive evaluation of the treatment system. Copper/iron doped zinc oxide (Cu-Fe-ZnO) was introduced to biochar to form a hybrid materials and used to treat HLL contaminated with 1,4 dioxane of 355.0 ± 11.7 mg/L. The Cu-Fe-ZnO/biochar removed 93.1 ± 8.7% of 1,4 dioxane at a dose of 0.6 g/L within 90 min, as compared with only 42.7 ± 3.3% by 1.2 g/L of bare biochar within 210 min. The Cu-Fe-ZnO/biochar degraded 1,4 dioxane into ethylene glycol, glycolic acid, and formic acid. The 1,4 dioxane removal mechanisms were investigated using the density functional theory, demonstrating that doping of ZnO with metal atoms (Cu-Fe) narrowed the bandgap from 3.307 eV to 2.736 eV. The enhanced photocatalytic activity of ZnO was also supported by the role of biochar in increasing the reactive species and adsorbing the pollutant molecules. The high degradation efficiency of 1,4 dioxane using small catalyst doses with short reaction times would reduce the treatment cost and improve the system's applicability for treating HLL and industrial effluents.