Novel application of cotton stalk as a waste derived catalyst in the low temperature SCR-deNOx process

Abstract

The use of activated carbon derived from cotton stalk as a potential catalytic support material in the application of NO removal from coal combusted flue gas was experimentally investigated utilizing the SCR-deNOx process. Cotton stalk samples infused with phosphoric acid were chemically activated (CACS) and co-activated (CO-ACS) and impregnated with the metal configuration Mn/Ce (1:2M ratio) representing 4wt.% relative to the support material. The CACSx–Mn/Ce and CO-ACSx–Mn/Ce catalysts provided NO conversion efficiencies ranging between ∼10% and 68%. The addition of phosphoric acid significantly increased the BET surface area (m2g−1) of the respective CACSx–Mn/Ce and CO-ACSx–Mn/Ce catalysts. However based on the experimental and analytical findings this study suggests that the NO conversions efficiencies of the CACSx–Mn/Ce and CO-ACSx–Mn/Ce catalysts are far more dependent on the wt.% of the metal loading than the physical parameters such as the pore size, pore structure and surface area. The relatively lower NO conversion efficiencies may also be further due to the neutralization of the Lewis and Brönsted acid sites of the catalysts by the presence of any alkali metals within the cotton stalk. The cotton stalk derived catalytic support has shown a great potential for possible application within the SCR-deNOx process. It is further suggested that higher NO conversion efficiencies can be realized by an increase in the metal loadings of Mn/Ce for the CACSx–Mn/Ce and CO-ACSx–Mn/Ce catalysts.