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Both the performance and regenerability of SO 2 adsorbents made of CuO supported on SBA-15 ordered mesoporous silica were studied for a cyclic DeSOx process under wet and dry conditions. H 2 O vapor decreases the performance of a 16 wt% loading CuO/SBA-15 (16CuO/SBA-15) adsorbent along the adsorption/regeneration cycles performed at 400 °C. Indeed, the SO 2 breakthrough adsorption capacity of this adsorbent after ten adsorption- regeneration cycles under wet conditions (5 vol% of H 2 O) decreases of 61% compared to the SO 2 performance obtained under dry conditions. The impact of the temperature as well as the CuO loading on the performance and regenerability of CuO/SBA-15 sorbents were also investigated under dry and wet conditions. XRD, TEM/EDX, N 2 physisorption characterizations of the adsorbents were performed after the last cycle to correlate the structural and textural properties of the adsorbents and therefore the copper species, with the performance of the adsorbents. Increasing the temperature up to 450 °C with or without water increases the SO 2 adsorption capacity of the 16CuO/SBA-15 adsorbent with higher SO 2 adsorption capacity at 450 °C with water than without water. In the presence of water vapor, the 8CuO/SBA-15 adsorbent presents the highest average loss of SO 2 adsorption capacity at the breakthrough of around 71% when expressed in mg SO 2 / g CuO , compared to the ones obtained with the 16CuO/SBA-15 and the 26CuO/SBA-15 adsorbents. The increase of the CuO loading up to 26 wt%, shows that the contribution of the surface copper active phase highlighted by the desorption curves, decreases significantly for the highest CuO loading under wet conditions. Moreover, with or without water, the highest total SO 2 adsorption capacities obtained after the tenth cycle are observed for the lowest CuO loading (8 wt% of CuO: 547 and 495 mg SO 2 / g CuO without and with H 2 O, respectively). These higher total SO 2 adsorption capacities could be explained by a better CuO phase dispersion on the SBA-15 support, which makes the copper active species more reactive especially with H 2 O. [Display omitted] • SO 2 adsorption capacity of CuO/SBA-15 adsorbents decreases with water vapour at 400 °C. • Blocking of the Cu-based active sites by competitive physisorption of H 2 O and SO 2. • Agglomeration of the CuO active phase is intensified in presence of water vapor. • Increase of the SOx trapping performance with H 2 O at high temperature 450 °C. [ABSTRACT FROM AUTHOR]

[Display omitted] • Partially reversible negative impact of H 2 O vapor on SO 2 trapping with CuO/SBA–15. • Competitive adsorption of H 2 O versus SOx on copper active sites. • H 2 O vapor probably generates highly stable hydroxy-sulfate species of copper. • Migration/coalescence of copper active phase enhanced with H 2 O vapor in gas phase. • The harmful effects of H 2 O at 450 °C is reduced with the decrease of the CuO loading. The effect of water vapor on the DeSOx performance of regenerable CuO/SBA-15 adsorbent was investigated for different temperatures of adsorption/regeneration cycles and CuO loadings. At 400 °C a significant decrease of both dynamic and total SO 2 adsorption capacity compared to the ones measured without water was observed. This decrease could be related to a faster migration and aggregation of the CuO active phase, an adsorption competition between water and SO 2 molecules on the active sites and/or the formation of copper based sulfate/oxysulfate/hydroxy-oxysulfate species difficult to decompose during the reductive regeneration step. On the other hand, at 450 °C water vapor leads to an increase of the total SO 2 adsorption capacity by more than 20%, which might be due to an acceleration of the oxidation of SO 2 , a faster chemisorption of the sulfur species on the active sites and a more efficient regeneration step with regard to 400 °C. The decrease of the CuO loading from 15 to 7 wt% leads to a lower deactivation (i.e loss of SO 2 adsorption capacity) at the breakthrough of the adsorbent under wet conditions. Whatever the temperature and the CuO loading, once the water vapor is removed from the gas stream, the dynamic SO 2 adsorption capacities are totally or partially recovered. This behavior shows that the deactivation of the CuO/SBA–15 adsorbent induced by water vapor is a reversible or partially reversible phenomenon. It appears that during the DeSOx process a migration towards the pore mouth and an aggregation of the CuO active phase occur faster under water vapor conditions with the formation of large particles of CuO. [ABSTRACT FROM AUTHOR]

• SO 2 adsorption capacity of CuO/SBA-15 greatly increases with NO 2 in gas phase. • CO oxidation catalysed by CuO species. • Partial reduction of NO 2 into NO catalysed by copper oxide. • Reaction SO 2 + NO 2 → SO 3 + NO seems to play a major role in the increased DeSOx performance. • In gas phase: oxidation of SO 2 by NO 2 to form SO 3 is catalysed by copper active sites. SOx (i.e. SO 2 and SO 3) compounds are known to be a major source of atmospheric pollution and to be responsible of adverse effects on the human health and on the environment. To reduce the SOx emissions, numerous abatement technologies were developed and applied. Nowadays, the most attractive one seems to be the process that use a regenerable SOx adsorbent. In this respect, a CuO (15 wt.%)/SBA-15 regenerable type SOx adsorbent has been developed. Under standard conditions (a gaseous mixture of N 2 , SO 2 and O 2), the adsorbent exhibits a stable adsorption capacity around 50 mg SO 2 /g ads along 10 cycles at 400 °C (for a 75 ppm of SO 2 exhaust concentration). The main aim of this work is to study the impact of various regulated pollutants such as CO, CO 2 , NO and NO 2 on the SO 2 adsorption capacity of the CuO (15 wt.%)/SBA-15 adsorbent. In the presence of CO and CO 2 , the SO 2 adsorption performance of the CuO/SBA adsorbent is similar to the one observed under standard conditions. On the other hand, under NO and NO 2 atmosphere, the dynamic and total adsorption capacities of the adsorbent are enhanced up to 25% and no deactivation occurs along the cycles. The increase may be related with the synergetic effect between NO 2 and SO 2 towards the sulphate formation. The CuO/SBA-15 adsorbent before and after multicycle SO 2 adsorption in the presence of regulated pollutants and regeneration under 0.5 vol.% of H 2 have been characterized by XRD and N 2 physisorption. No significant structural and textural change is observed compared to the CuO/SBA-SO 2 adsorbent. [ABSTRACT FROM AUTHOR]