A Biophysicochemical Model for NO Removal by the Chemical Absorption-Biological Reduction Integrated Process

The chemical absorption-biological reduction (CABR) integrated process is regarded as a promising technology for NO_x removal from flue gas. To advance the scale-up of the CABR process, a mathematic model based on mass transfer with reaction in the gas, liquid, and biofilm was developed to simulate and predict the NO_x removal by the CABR system in a biotrickling filter. The developed model was validated by the experimental results and subsequently was used to predict the system performance under different operating conditions, such as NO and O₂ concentration and gas and liquid flow rate. NO distribution in the gas phase along the biotrickling filter was also modeled and predicted. On the basis of the modeling results, the liquid flow rate and total iron concentration were optimized to achieve >90% NO removal efficiency. Furthermore, sensitivity analysis of the model revealed that the performance of the CABR process was controlled by the bioreduction activity of Fe(III)EDTA. This work will provide the guideline for the design and operation of the CABR process in the industrial application.