Co-blending modification of activated coke using pyrolusite and titanium ore for low-temperature NOx removal

Abstract

Activated coke (AC) has great potential in the field of low-temperature NO removal (DeNOx), especially the branch prepared by blending modification. In this study, the AC-based pyrolusite and/or titanium ore blended catalysts were prepared and applied for DeNOx. The results show blending pyrolusite and titanium ore promoted the catalytic performance of AC (Px@AC, Tix@AC) clearly, and the co-blending of two of them showed a synergistic effect. The (P/Ti-1/2)15@AC performed the highest NO conversion of 66.4%, improved 16.9% and 16.0% respectively compared with P15@AC and Ti15@AC. For the (P/Ti-1/2)15@AC DeNOx, its relative better porous structure (SBET = 364 m2/g, Vmic = 0.156 cm3/g) makes better mass transfer and more active sites exposure, stronger surface acidity (C–O, 19.43%; C=O, 4.16%) is more favorable to the NH3 adsorption, and Ti, Mn and Fe formed bridge structure fasted the lactic oxygen recovery and electron transfer. The DeNOx of (P/Ti-1/2)15@AC followed both the E–R and L–H mechanism, both the gaseous and adsorbed NO reacted with the activated NH3 due to the active sites provided by both the carbon and titanium.

Low-Temperature Selective Catalytic Reduction of NO with NH3 over a Biochar-Supported Perovskite Oxide Catalyst

“…When NO was fed again, the NO outlet concentration increased in a short time of 13 min in stage B 4 and then performed a gradual increase and reached a steady state in 20 min in stage B 5 . The total time span of stage B 4 and stage B 5 was longer than that of stage B 1 (25 min), indicating that part of NO participated in the reaction presented in the adsorption state; similar phenomena were also observed for other carbon-based SCR catalysts …”

“…The total time span of stage B 4 and stage B 5 was longer than that of stage B 1 (25 min), indicating that part of NO participated in the reaction presented in the adsorption state; similar phenomena were also observed for other carbon-based SCR catalysts. 49 As for NH 3 variation, Figure 12c shows the transient response of NO with NH 3 . When NH 3 was shut off, the NO outlet concentration quickly increased in stage C 2 in 33 min and then slowly increased to 494 ppm in stage C 3 in 86 min, suggesting that the adsorbed NH 3 on the LMO/BCNA surface participated in the NO reduction.…”