Effect of an Alumina Supported Palladium Catalyst on the Magnesium Sulfate Decomposition Kinetics

Abstract

The sulfur related thermochemical water-splitting cycles are an important class of chemical processes considered for hydrogen production. Recently, the magnesium sulfate thermal decomposition has been reported as a potential unit operation in one of these cycles. Therefore, some interest has been observed in the use of catalysts to lower the activation energy of such reactions. In this context, the present manuscript reports the thermodynamics and kinetics modeling results associated with this reaction system in the presence of a Pd catalyst supported over γ-Al 2 O 3 . The presence of such species is responsible for shifting the decomposition temperature to lower values in at least 100 °C. It was observed that the magnesium content is still oriented towards MgO formation. The obtained results indicate that the Pd/Al 2 O 3 catalyst could be a good alternative in reducing the thermal decomposition temperature as its presence was responsible for diminishing the process activation energy from 368.2 to 258.8 kJ.mol −1 .

Thermodynamics and Kinetic Modeling of the ZnSO4·H2O Thermal Decomposition in the Presence of a Pd/Al2O3 Catalyst

“…For each analysis, the modeling quality was determined by the value of the correlation coefficient (R 2 ) calculated for each dataset. This methodology was recently successfully applied for the thermal decomposition modeling of MgSO 4 [40] and potassium alum [46] reaction systems.…”

“…In the work of Mello et al [40], who also used the Pd/Al 2 O 3 catalyst, it was observed that palladium tended to oxidize and initiate the formation of PdO up to approximately 900 • C in the reaction system and then dissociate, returning to the metallic form at higher temperatures. According to O'Keefe et al [54] and Barbarossa et al [17], the oxide's catalytic activity forms in the decomposition of sulfur trioxide.…”

“…However, there is a paucity of information on the effects of incorporating catalytic materials on the kinetic parameters of these thermal decomposition processes. Consequently, there is a lack of information about the behavior of the reaction system through a more quantitative approach, with one reported work so far for MgSO 4 .7H 2 O thermal decomposition [40]. Nevertheless, this sulfate tends to decompose directly into its oxide in a manner that is novel to systems in which an intermediate is formed (e.g., ZnO•2ZnSO 4 from ZnSO 4 and FeSO 4 from Fe 2 (SO 4 ) 3 ).…”

Simulação Termodinâmica E Modelagem Cinética Do Processo De Decomposição De Sulfatos Com Diferentes Níveis De Estabilidade Térmica Na Presença De Catalisadores

“…All the calculations were made using Python 3.8.2. This methodology was recently successfully applied for the thermal decomposition modeling of ZnSO 4 [27], MgSO 4 [28] and potassium alum [57] reaction systems. shows the mass loss curves of pure ammonium sulfate from 25 to 500°C for three heating rates (10,15 and 20°C.min -1 ).…”

“…In industrial processes, the leach residue is generally not pure since it contains smaller amounts of other sulfates, such as iron, aluminum, and manganese. The decomposition of the eventually precipitated sulfates can be a route to obtain sulfur dioxide and metal oxides [27,28].…”