Waste-derived activated carbons for control of nitrogen oxides

Abstract

Activated carbons were produced from waste and investigated for their efficiency for the removal of mono-nitrogen oxides (NO x ) in simulated flue gases at a low temperature. The wastes used were waste biomass (date seeds), processed municipal solid waste in the form of refuse-derived fuel and waste tyres. The morphology, porous texture and surface chemistry of the prepared activated carbons were evaluated by scanning electron microscopy, energydispersive X-ray spectrometry, nitrogen adsorption and Boehm titration, and were compared with several commercial activated carbons. The carbons were then investigated in terms of their use in adsorbing NO x at a low temperature.The waste-derived activated carbons had NO x adsorption efficiencies at 50°C which were between 50 and 70% of those achieved for the commercial activated carbons. Increasing the adsorption temperature from 25 to 100°C significantly reduced nitrogen oxide (NO) adsorption. It was also shown that the NO adsorption efficiency depends on the porous structure, particularly the presence of micropores in the activated carbon, but to a lesser extent on the surface area of the carbons and acid-base surface groups on the carbon surface.

Influence of Carbonisation Temperature on the Surface Pore Characteristics of Acid-Treated Oil Palm Empty Fruit Bunch Activated Carbon

“…The size and the shape of the pores can greatly influence the accessibility to the carbon's internal area, thereby improving the mass transport of reacting gas from the exterior surface to an active site beneath the surface and transport of products in the opposite direction [36]. The significance of microporous structure for NO removal is also supported by several previous studies including a study on waste-derived activated carbons for control of nitrogen oxides [37].…”

Thermal decomposition and gasification of biomass pyrolysis gases using a hot bed of waste derived pyrolysis char

“…The tyre char had a higher number of acidic groups than date stones and RDF char which were found to be basic in nature. (Al-Rahbi et al, 2015).…”

“…The ash composition and the type of metal present in the ash could play a role in enhancing tar reduction due to catalytic effects. The significant reactivity of tar with tyre char could be due to the catalytic effects of the minerals such as Zn, which was present in quite a high percentage of 2.95 wt.% for the raw tyre sample used in this work (Al-Rahbi, et al, 2015).…”

Editorial

“…The paper by Al-Rahbi et al (2016) also looks at the energy sector and the need to remove and reduce the nitrogen oxide gases (NO x ) generated by combustion processes, irrespective of whether the combusted materials are fossil-based or renewable. Reduction of NO x is a regulatory requirement because NO x is a greenhouse gas as well as a health hazard.…”