Enhanced pretreatment of tert-butyl acrylate production wastewater by fluidized/fixed bed treatment system

Purifying wastewater and saving energy have become important prerequisites for global sustainable development. Currently, the application of various wastewater treatment processes for tert-butyl acrylate production wastewater is still restricted by energy-intensive factors. Aiming at addressing the trade-offs in water-energy nexus in purification of tert-butyl acrylate production wastewater, this study proposed a fluidized/fixed bed treatment system for catalytic oxidation purification of tert-butyl acrylate production wastewater. A high calorific value of rectification residue produced by the production of tert-butyl acrylate was introduced to simultaneously achieve low energy consumption and efficient purification of tert-butyl acrylate production wastewater and rectification residue. The effects of the operating conditions of fluidized and fixed beds and their coupling process on the purification effect of tert-butyl acrylate production wastewater were evaluated. Results showed that the efficiency of purifying tert-butyl acrylate production wastewater and rectification residue using the fluidized/fixed bed treatment system was considerable. The calculation results showed that the thermal balance of the system was enhanced due to the introduction of rectification residue, and the energy-saving rate reached 18%. Tert-butyl acrylate production wastewater was oxidized to small-molecule chemicals by proton transfer and demethylation during degradation process which was investigated by gas chromatography–mass spectrometry. Stability experiments indicated that the average removal efficiency of chemical oxygen demand in fluidized/fixed bed treatment system was 97.0%–98.5% for 600 h of continuous operation. The Cu/Ce/Mn catalyst exhibited good stability. Therefore, fluidized/fixed bed treatment system can effectively purify high-concentration organic wastewater and is a promising technology.