Flow-through catalytic membrane reactors for the destruction of a chemical warfare simulant: Dynamic performance aspects

• We fabricated multilayer alumina membranes impregnated with platinum.
• Catalytic activity and membrane pore size affect the rate of membrane pore blockage.
• Initial activity of the catalytic membrane can be restored to an acceptable extent.
• We developed a mathematical model to describe the dynamic performance of a FTCMR.
• Flow-through catalytic membrane reactors (FTCMR) are promising to destroy CWAs in air.

A model was developed to describe the dynamic performance of a flow-through catalytic membrane reactor (FTCMR) used for the destruction of a chemical warfare agent (CWA) simulant, specifically dimethyl methylphosphonate (DMMP). For such a reactor, after a certain time period during which it provides full protection, its performance begins to decline, as manifested by a gradual decline in the thermocatalytic destruction rate of the DMMP and discernible changes in the membrane's throughput. The model ascribes these phenomena to changes in the catalytically active membrane surface area and in the accessible membrane pore volume, which are brought upon by the deposition of phosphorous-containing by-products of the DMMP's thermocatalytic decomposition reaction. Such a hypothesis is supported by experimental data for both fresh and aged membranes that substantiate significant losses in surface area and pore volume, and indicate the presence of phosphorous in the aged membranes. The model was used to fit the experimental data from a FTCMR operating under a total flow-through (100% stage-cut) mode of operation, and was shown to describe well the experimental data. In addition, the model was utilized in a predictive mode to describe the performance of a FTCMR employing another membrane from the same batch and catalytically activated under the same procedure, but operating under different operating conditions (0% stage-cut). The model was shown to provide an adequate fit to the experimental data. Following such validation, the model has been used to gain further insight into the impact of the various reactor parameters on FTCMR performance. Its use has, subsequently, led to the development of a novel reactor configuration that significantly expands the operating performance window of the FTCMR for the thermocatalytic CWA destruction.

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