LHHW/RSM reaction rate modeling for Co-Mn/SiO2 nanocatalyst in Fishcher-Tropsch synthesis.

This study aims to assess the kinetics of Fischer-Tropsch (FT) reaction over the cobalt-manganese nanoparticles supported by silica oxide. Nanoparticles were synthesized by the thermal decomposition method using "[Co(NH3)4CO3]MnO4" complex and characterized by XRD, TEM, and BET techniques. The kinetics of the process were evaluated using a combination of Langmuir-Hinshelwood-Hougen-Watson (LHHW) and response surface methodology. Correlation factors of 0.9902 and 0.962 were obtained for the response surface method (RSM) and LHHW, respectively. The two methods were in good agreement, and the results showed that the rate-determining step was the reaction of the adsorbed methylene with the adsorbed hydrogen atom, and only carbon monoxide molecules were the most active species on the catalyst surface. A temperature of 502.53 K and a CO partial pressure of 2.76 bar are proposed as the optimal conditions by RSM analysis. The activation energy of CO consumption reaction was estimated to be 61.06 kJ/mol.

Enhanced photocatalytic performance of UiO-66-NH2/TiO2 composite for dye degradation.

In this study, the performance of TiO2, ZnO, UiO-66-NH2 and UiO-66-NH2/TiO2 nanoparticles was investigated. They apply as photocatalysts for the destruction of organic reactive red dye 120 (RR120) under UV light. In order to determine the optimal conditions, effects of different catalysts and initial dye concentration, H2O2 content and catalyst loading parameters were examined. Taguchi-designed experimental method was used to obtain optimal test conditions. The physical and chemical properties of synthetic photocatalysts were investigated by SEM, XRD, EDX, BET and DRS. SEM images show that the globular particles of titania are well placed on the surface of the metal-organic framework (MOF). XRD and EDX analyses also confirmed the presence of titania in the synthesised UiO-66-NH2/TiO2 photocatalyst. Optimal values of H2O2, pH, the amount of catalyst, the dye concentration and the type of available photocatalyst to remove the RR120 dye, were obtained by 80 µl/l, 3 mg/l, 5 mg/l and 20 mg/l, UiO-66-NH2/TiO2 catalyst, respectively. The required time for complete removal of RR120 dye under detection limit of 0.136 mg/l in optimal conditions was 10 min. The RR120 photocatalytic degradation followed the first-order kinetic equation according to the Langmuir-Hinshelwood model (kapp = 0.407 min-1). The result of optimisation showed the 20 wt% of the titania on MOF (UiO-66-NH2) photocatalyst can be used in advanced oxidation processes, and it can be used as a suitable option for cleaning coloured effluent.