Agricultural Waste Derived Catalysts for Low Temperature SCR Process: Optimization of Preparation Process, Catalytic Activity and Characterization

Abstract

Carbon-based catalytic materials have received significant attention for low temperature flue gas denitrification (DeNO x ) process, due to their physicochemical properties and ease of modification. To improve the DeNO x efficiency, preparation of biochar catalyst supports was conducted that included the acid treatment of the agricultural wastes rice straw, corn cobs and lotus leaves. Taguchi experimental design (3 4 ) was employed to screen suitable carbon materials and optimize the preparation parameters of the biochar. All of the acid-modified and unmodified samples were evaluated to determine their performance and they were characterized by using SEM, BET and FT-IR analysis. The experimental and characterization results showed that acid modification of the biochars improved their DeNO x performance, which may have been due to the changes in the physical and chemical properties of the carbon material following the acid treatment. The optimum combination in the acid modification procedure was found to be the use of lotus leaf carbon treated with an acid/mass ratio of 1.50 and a pyrolysis temperature of 800°C. The biochar prepared using these optimum preparation parameters were then employed as a carrier to support an active catalyst component (MnO x ). The lotus leaf biochar supported 10 wt% manganese catalyst prepared using ultrasonic impregnation method exhibited nearly 90% NO x conversion at 250°C at a high space velocity of 45, 000 -1 , and it exhibited strong resistance to H 2 O. Additional studies showed that higher redox capacity and suitable surface acidity were two of the deciding factors in the improved low temperature SCR performance of the 10% Mn/LBC catalysts.

Lotus leaves‐derived MnOx/biochar as an efficient catalyst for low‐temperature NH3‐SCR removal of NOx: effects of modification methods of biochar

“…40,41 The peak at 1023 cm −1 was attributed to the stretching vibration of C O C. 42 The peaks at 872 cm −1 were assigned to C H out-of-plane bending vibrations. 43 For the HNO 3 modification, new peaks of 1382 cm −1 and 1243 cm −1 were attributed to the stretching vibration of C O or C-O-C 22,31 in the LBC-H samples. The LBC-N catalyst exhibited new peaks at 2923 cm −1 and 2853 cm −1 due to asymmetric C O stretching vibration and stretching vibration of N H, 22,31 respectively.…”

“…43 For the HNO 3 modification, new peaks of 1382 cm −1 and 1243 cm −1 were attributed to the stretching vibration of C O or C-O-C 22,31 in the LBC-H samples. The LBC-N catalyst exhibited new peaks at 2923 cm −1 and 2853 cm −1 due to asymmetric C O stretching vibration and stretching vibration of N H, 22,31 respectively. A peak at 1425 cm −1 was present in the spectrum of the surface of the LBC-OH samples, which was attributed to C OH bend/ O H deformation.…”

“…21 China is a large agricultural country and has a large amount of agricultural waste, which can be used for preparing biochar by a variety of methods. 22 Moreover, biochar is cheap, readily available, low cost and environmentally friendly. 23,24 These attributes make this material attractive for development into a catalyst for low-temperature NH 3 -SCR removal of NO x .…”

“…However, the high cost of these materials continues to be the main impediment to their widespread use in the NO x removal processes 21 . China is a large agricultural country and has a large amount of agricultural waste, which can be used for preparing biochar by a variety of methods 22 . Moreover, biochar is cheap, readily available, low cost and environmentally friendly 23,24 .…”

Photodegradation of Nitrogen Oxide under Solar Light Using a Facile Synthesis Catalyst

“…It contributes to acid rain, air pollution, and ozone depletion (Biswas & Mahajan, 2021;Biswas et al, 2021;Chen et al, 2017;Liu et al, 2019;Q. Wang et al, 2020;Yu et al, 2020).…”