Study on the Catalytic Cracking and Deep Purification Process for High-concentration DMF Wastewater

High-concentration N,N-dimethylformamide (DMF) wastewater presents a major challenge in hazardous chemical waste treatment due to its chemical stability, poor biodegradability, and significant biotoxicity. To address the insufficient thermal stability of conventional catalyst supports, limited activity of single metals, and the lack of synergistic catalyst–reactor process studies in thermocatalytic oxidation, this thesis focuses on multiphase fluidized-bed catalytic cracking and establishes an integrated “catalyst–reactor–process” technical system. Transition metal-doped alumina aerogel catalysts were prepared via a sol–gel method, with Ni and Cu identified as the optimal active components. The optimized Ni 3 Cu 2 O x –Al 2 O 3 catalyst (Ni/Cu oxide mass ratio of 3:2, calcined at 550 °C for 5 h) achieved 99.96% DMF cracking and 98.66% chemical oxygen demand (COD) removal for 8000 mg/L DMF at 380 °C. Characterization revealed a three-dimensional mesoporous structure with a specific surface area of 236.44 m 2 /g. The fluidized-bed operating parameters were systematically optimized, and good catalytic performance was obtained over a DMF concentration range of 8000–32000 mg/L. No apparent competitive inhibition was observed in DMF–phenol mixed wastewater, demonstrating the general applicability of the catalytic process. The constructed fluidized-bed/fixed-bed two-stage series process achieved deep purification, with DMF cracking approaching 100% and a maximum COD removal of 99.33%. This study provides an efficient catalytic process scheme for the harmless treatment of high-concentration DMF wastewater. Graphical