Precise regulation of acid pretreatment for red mud SCR catalyst: Targeting on optimizing the acidity and reducibility

Highlights

• The optimum SCR activity was realized by tuning the acid pretreatment.

• Optimized catalysts showed NO_x conversion above 90%.

• The NH₃ and NO adsorption capacity of Al-O₃-Fe is stronger than Fe-O₃-Fe.

• The formation of almandine consumes Fe³⁺ and Al³⁺ and weakens their interaction.

Abstract

Red mud (RM), as an alkaline waste, was recently proved to be a promising substitute for the SCR catalyst. Dealkalization could improve the acidity and reducibility of red mud, which were critical for SCR reaction. However, the dealkalization effect depended on the reaction between acid solution and red mud. In this study, we realized the directional control of the chemical state of active sites through tuning the acid pretreatment (dealkalization) process. The pretreatment endpoint was controlled at pH values of 3–5 with diluted nitric acid. When the pH values of red mud were 3 and 5 (CRM-3 and CRM-5), activated catalysts showed NO_x conversion above 90% at 275°C–475°C. The high initial reaction rate, Ce³⁺/(Ce³⁺ + Ce⁴⁺) ratio, and surface acidity accounted for the excellent SCR performance of CRM-5 catalyst. Meanwhile, more Fe³⁺ on the CRM-3 surface improved the NH₃ adsorption. There was a strong interaction between Al and Fe in both CRM-5 and CRM-3 catalysts. DFT results showed that the adsorption capacity of the Al-O₃-Fe for NH₃ and NO is stronger than that of Fe-O₃-Fe, which enhanced the NO_x conversion of the catalyst. However, the almandine was formed in CRM-4, consumed part of Fe³⁺ and Al³⁺, and the interaction between Al and Fe was weakened. Also, deposited almandine on the catalyst surface covered the active sites, thus leading to lower NH₃-SCR activity.

Graphical abstract

Keywords

Air pollution control / Nitrogen oxides / Selective catalytic reduction / Red mud / Solid waste utilization

References

[1] Chen Q Z, Zhang X, Li B, Niu S L, Zhao G J, Wang D, Peng Y, Li J H, Lu C M, Crittenden J (2021). Insight into the promotion mechanism of activated carbon on the monolithic honeycomb red mud catalyst for selective catalytic reduction of NO_x. Frontiers of Environmental Science & Engineering, 15(5): 92

[2] Gao F Y, Tang X L, Yi H H, Li J Y, Zhao S Z, Wang J G, Chu C, Li C L (2017). Promotional mechanisms of activity and SO₂ tolerance of Co- or Ni-doped MnO_x-CeO₂ catalysts for SCR of NO_x with NH₃ at low temperature. Chemical Engineering Journal, 317: 20–31

[3] Gong Z Q, Ma J, Wang D, Niu S L, Yan B H, Shi Q L, Lu C M, Crittenden J (2020). Insights into modified red mud for the selective catalytic reduction of NO_x: Activation mechanism of targeted leaching. Journal of Hazardous Materials, 394: 122536

[4] Guo R T, Li M Y, Sun P, Pan W G, Liu S M, Liu J, Sun X, Liu S W (2017). Mechanistic investigation of the promotion effect of Bi modification on the NH₃-SCR performance of Ce/TiO₂ catalyst. Journal of Physical Chemistry C, 121(49): 27535–27545

[5] Han L P, Cai S X, Gao M, Hasegawa J Y, Wang P L, Zhang J P, Shi L Y, Zhang D S (2019a). Selective catalytic reduction of NO_x with NH₃ by using novel catalysts: State of the art and future prospects. Chemical Reviews, 119(19): 10916–10976

[6] Han L P, Gao M, Feng C, Shi L Y, Zhang D S (2019b). Fe₂O₃-CeO₂@Al₂O₃ nanoarrays on Al-mesh as SO₂-tolerant monolith catalysts for NO_x reduction by NH₃. Environmental Science & Technology, 53(10): 5946–5956

[7] Hu H, Cai S X, Li H R, Huang L, Shi L Y, Zhang D S (2015). Mechanistic aspects of deNO_x processing over TiO₂ supported Co-Mn oxide catalysts: Structure-activity relationships and in situ DRIFTs analysis. ACS Catalysis, 5(10): 6069–6077

[8] Jia H Z, Shi Y F, Nie X F, Zhao S, Wang T C, Sharma V K (2020). Persistent free radicals in humin under redox conditions and their impact in transforming polycyclic aromatic hydrocarbons. Frontiers of Environmental Science & Engineering, 14(4): 73

[9] Jiang Y, Xing Z M, Wang X C, Huang S B, Wang X W, Liu Q Y (2015). Activity and characterization of a Ce-W-Ti oxide catalyst prepared by a single step sol-gel method for selective catalytic reduction of NO with NH₃. Fuel, 151(1): 124–129

[10] Lee T Y, Bai H L (2018). Metal sulfate poisoning effects over MnFe/TiO₂ for selective catalytic reduction of NO by NH₃ at low temperature. Industrial & Engineering Chemistry Research, 57(14): 4848–4858

[11] Liu J, Li G Q, Zhang Y F, Liu X Q, Wang Y, Li Y (2017a). Novel Ce-W-Sb mixed oxide catalyst for selective catalytic reduction of NO_x with NH₃. Applied Surface Science, 401: 7–16

[12] Liu J X, Liu J, Zhao Z, Tan J B, Wei Y C, Song W Y (2018). Fe/Beta@SBA-15 core-shell catalyst: Interface stable effect and propene poisoning resistance for NO abatement. AIChE Journal, 64(11): 3967–3978

[13] Liu J X, Zhao Z, Xu C M, Liu J (2019). Structure, synthesis, and catalytic properties of nanosize cerium-zirconium-based solid solutions in environmental catalysis. Chinese Journal of Catalysis, 40(10): 1438–1487

[14] Liu S, Lin Q J, Liu J Y, Xu S H, Wang Y, Xu H D, Wang J L, Chen Y Q (2020). Enhancement of the hydrothermal stability of WO₃/Ce_0.68Zr_0.32O₂ catalyst by silica modification for NH₃-SCR. ACS Applied Energy Materials, 3(1): 1161–1170

[15] Liu Z M, Ihl Woo S (2006). Recent advances in catalytic deNO_x Science and Technology. Catalysis Reviews. Science and Engineering, 48(1): 43–89

[16] Liu Z, Yu R T, Dong Y P, Li W, Lv B L (2017b). The adsorption behavior and mechanism of Cr (VI) on 3D hierarchical a-Fe₂O₃ structures exposed by (0 0 1) and non-(0 0 1) planes. Chemical Engineering Journal, 309: 815–823

[17] Lyu F, Hu Y H, Wang L, Sun W (2021). Dealkalization processes of bauxite residue: a comprehensive review. Journal of Hazardous Materials, 403: 123671

[18] Lyu Z K, Niu S L, Lu C M, Zhao G J, Gong Z Q, Zhu Y (2020). A density functional theory study on the selective catalytic reduction of NO by NH₃ reactivity of α-Fe₂O₃ (0 0 1) catalyst doped by Mn, Ti, Cr and Ni. Fuel, 267: 117147

[19] Ma S B, Tan H S, Li Y S, Wang P Q, Zhao C, Niu X Y, Zhu Y J (2020). Excellent low-temperature NH₃-SCR NO removal performance and enhanced H₂O resistance by Ce addition over the Cu_0.02Fe_0.2-Ce_yTi_1−xO_x (y= 0.1, 0.2, 0.3) catalysts. Chemosphere, 243: 125309

[20] Meng Y, Liu W V, Fiedler H, Zhang J L, Wei X R, Liu X H, Peng M, Zhang T T (2021). Fate and risk assessment of emerging contaminants in reclaimed water production processes. Frontiers of Environmental Science & Engineering, 15(5): 104

[21] Qiu S J, Liu J J, Zhang L, Zhang Q, Peng Y Z (2021). Sludge fermentation liquid addition attained advanced nitrogen removal in low C/N ratio municipal wastewater through short-cut nitrification-denitrification and partial anammox. Frontiers of Environmental Science & Engineering, 15(2): 26

[22] Sun F W, Liu H B, Shu D B, Chen T H, Chen D (2019). The characterization and SCR performance of Mn-containing α-Fe₂O₃ derived from the decomposition of siderite. Minerals, 9(7): 393–404

[23] Wang B, Ma J, Wang D, Gong Z Q, Shi Q L, Gao C, Lu C M, Crittenden J (2021). Acid-pretreated red mud for selective catalytic reduction of NO with NH₃: Insights into inhibition mechanism of binders. Catalysis Today, 376: 247–254

[24] Wang D, Peng Y, Yang Q, Xiong S, Li J, Crittenden J (2018). Performance of modified La_xSr_1−xMnO₃ perovskite catalysts for NH₃ oxidation: TPD, DFT, and kinetic studies. Environmental Science & Technology, 52(13): 7443–7449

[25] Wang D, Yang Q L, Yang G P, Xiong S C, Li X S, Peng Y, Li J H, Crittenden J (2020). Rational tuning towards A/B-sites double-occupying cobalt on tri-metallic spinel: Insights into its catalytic activity on toluene catalytic oxidation. Chemical Engineering Journal, 399: 125792

[26] Wang P, Sun H, Quan X, Chen S (2016). Enhanced catalytic activity over MIL-100(Fe) loaded ceria catalysts for the selective catalytic reduction of NO_x with NH₃ at low temperature. Journal of Hazardous Materials, 301: 512–521

[27] Wu J K, Gong Z Q, Lu C M, Niu S L, Ding K, Xu L T, Zhang K (2018). Preparation and performance of modified red mud-based catalysts for selective catalytic reduction of NO_x with NH₃. Catalysts, 8(1): 35–50

[28] Yi H, Huang Y, Tang X, Zhao S, Gao F, Xie X, Wang J, Yang Z (2019). Mn-CeO_x/MeO_x(Ti, Al)/cordierite preparation with ultrasound-assisted for non-methane hydrocarbon removal from cooking oil fumes. Ultrasonics Sonochemistry, 53: 126–133

[29] Zha K W, Cai S X, Hu H, Li H R, Yan T T, Shi L Y, Zhang D S (2017). In situ DRIFTs investigation of promotional effects of tungsten on MnO_x-CeO₂/meso-TiO₂ catalysts for NO_x reduction. Journal of Physical Chemistry C, 121(45): 25243–25254

[30] Zhang H, Jin M, Xia Y (2012). Enhancing the catalytic and electrocatalytic properties of Pt-based catalysts by forming bimetallic nanocrystals with Pd. Chemical Society Reviews, 41(24): 8035–8049

[31] Zhang L, Li L L, Cao Y, Xiong Y, Wu S G, Sun J F, Tang C J, Gao F, Dong L (2015). Promotional effect of doping SnO₂ into TiO₂ over a CeO₂/TiO₂ catalyst for selective catalytic reduction of NO by NH₃. Catalysis Science & Technology, 5(4): 2188–2196

[32] Zhang Q L, Zhang Y Q, Zhang T X, Wang H M, Ma Y P, Wang J F, Ning P (2020). Influence of preparation methods on iron-tungsten composite catalyst for NH₃-SCR of NO: The active sites and reaction mechanism. Applied Surface Science, 503: 144190

[33] Zhao W, Zhong Q, Pan Y X, Zhang R (2013). Systematic effects of S-doping on the activity of V₂O₅/TiO₂ catalyst for low-temperature NH₃-SCR. Chemical Engineering Journal, 228(6): 815–823

Acknowledgements

This work was financially supported by the National Natural Science Foundation of China (Grant No. 21906090), the National Key Research and Development Program of China (Nos. 2017YFC0210200 and 2017YFC0212800), and the Primary Research & Development Project of Shandong Province (China) (Nos. 2018GSF117034 and 2019JZZY020305). The scientific calculations in this paper have been done on the HPC Cloud Platform of Shandong University (China).

Electronic Supplementary Material

Supplementary material is available in the online version of this article at https://doi.org/10.1007/s11783-021-1447-x and is accessible for authorized users.

RIGHTS & PERMISSIONS

2022 Higher Education Press