Methanol-Promoted Oxidation of Nitrogen Oxide (NO_x) by Encapsulated Ionic Liquids

Abstract

The removal of nitrogen oxides (NO x) has been extensively studied due to their harmful effects to health and environment. In this work, Encapsulated Ionic Liquids (ENILs) are used as catalysts for the NO oxidation at humid conditions and low temperatures. Hollow carbon capsules (C Cap) were first synthetized to contain different amounts of 1-butyl-3-methylimidazolium nitrate IL ([bmim][NO 3 ]), responsible for the catalytic oxidation. Then, the materials were characterized using different techniques, by analyzing microstructure, porosity, elemental composition and thermal stability. The catalytic performance of ENIL materials was tested for NO conversion at different conditions. Thus, NO concentration was fixed at 2,000 ppm at dry and humid conditions. Then, the methanol promotion of the reaction was demonstrated, increasing the NO conversion values in all cases, and the alcohol/water ratio was optimized. The temperature effect was studied as well, using the optimal conditions based on the previous measurements. The results reflect that humid conditions do not have a negative effect in terms of NO conversion when using ENILs, opposite behavior as the observed for C Cap and traditional catalysts studied before. Low amount of IL inside the material (40% in mass) was found to be the optimum for the task, reaching conversions of almost 45% in near industrial conditions of temperature and O 2 and H 2 O concentrations in the flue gas with a GHSV = 10,000 h-1 .

Non-catalytic NOx reduction for marine Diesel engine: an experimental approach

“…In addition to their prevalent use as eco-sustainable solvents for organic reactions, they have been used very recently in very few studies also to lower the sulfur and nitrogen content of fuels [13], thus reducing SOx and NOx emissions in a pre-combustion strategy, or to oxidize NOx in exhaust gases (post-combustion strategy).…”

Continuous NO Upcycling into Ammonia Promoted by SO2 in Flue Gas: Poison Can Be a Gift

“…As for the synergetic treatment and recycling of NO and SO 2 , some attempts have been made. By application of the strong oxidative capacity from oxidants, the mixture of NO and SO 2 is converted into NO 3 – and SO 4 2– , respectively, in which the upcycling of the NO pollutant is not achieved. − Other than their co-oxidation for environmental remediation, new conversion routes are expected for resource recovery. It is known that the dissolution and oxidation of SO 2 are facile to proceed, which indicates that SO 2 can be utilized as a potential reducing agent.…”

Solid–Gas Sorption System for Ammonia Storage and Delivery Driven by Engine Waste Heat for NOx Reduction of Diesel Engine

“…As a low-cost and reversible absorbent, urea has been used in commercial de-NOx products, such as AdBlue, a eutectic 32.5 wt% urea-water that can be injected into the exhaust gas flow for NOx conversion [5]. In addition, ionic liquids (ILs) and deep eutectic solvents (DESs) are researched as alternative green solvents for NH 3 absorption, as they have adjustable structures, higher ammonia storage capacity, and lower volatility than traditional water-based urea solutions [4,6,7]. However, rather than ammonia storage and delivery for SCR reaction, more research focuses on using ILs and DESs to absorb and convert NOx directly [8,9].…”