A bifunctional MnO_x@PTFE catalytic membrane for efficient low temperature NO_x-SCR and dust removal

Low-temperature selective catalytic reduction of NO_x combined with dust removal technique due to its energy conservation characteristic has been attracted much attention for fume purification. In this work, the MnO_x wrapped PTFE membrane with efficient dust removal and low-temperature NH₃-SCR has been prepared with a facile route. MnO_x with different crystal structures was uniformly grown around the PTFE fibrils through water bath. The flower-sphere-like MnO_x@PTFE(O-MnO_x@PTFE) and lamellar-interlaced ripple-like MnO_x@PTFE(W-MnO_x@PTFE) have large specific surface area which is favorable for enhancing catalytic performance. Also, the uniformly wrapped W-MnO_x around the PTFE fibrils optimized the pore structure for ultrafine dust capture. The membrane can almost 100% reject particles that are smaller than 1.0 μm with a low filtration resistance. Meanwhile, W-MnO_x@PTFE with more surface chemisorbed oxygen has the best NO conversion efficiency of 100% at a comparatively low and wide activity temperature window of 160–210 °C, which is far to the thermal limitation of the PTFE. Therefore, this efficient and energy conserving membrane has a bright application prospects for tail gas treatment compared to the original treatment process.