In this study, the catalyst activity of Fe2O3 supported on Graphene for Iraqi gas oil oxidation desulfurization (ODS) by hydrogen peroxide (H2O2) was investigated. The prepared catalyst was synthesized by wet impregnation for ferric nitrate as a Fe2O3 precursor while Graphene represented as catalyst support. The synthesized catalyst was characterized by XRD, FTIR, and EDS analysis. The experiments were designed according to three-level for three variables by Box-Behnken experimental design; Stirring time, catalyst dosage and temperature while the sulfur removal efficiency acts as experiment response. Catalyst activity was studied by ODS reaction for Iraqi gas oil (sulfur content 9400 ppm) at temperature range (40-60 ºC), stirring time (160-240 minutes) and catalyst dosage (0.5-2.5 g), the results show maximum sulfur removal efficiency 90% at stirring time, catalyst dosage and temperature 240 min, 1.5 g, and 60 ºC, respectively. ANOVA analysis shows the important effect of each independent variable on sulfur removal efficiency (response) as following influential order; stirring time, reaction temperature and catalyst dosage. Kinetics calculation showed that the ODS reaction obeys pseudo first-order reaction with reaction rate constant equal 1.0837, 1.5893, and 2.5053 at temperature 40, 50, and 60 ºC, respectively, while activation energy equal 36.26 kJ/mol. Copyright © 2020 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

This study used the adsorption method to remove sulfur compounds from light naphtha fuel by using calcite and modified calcite as adsorbents. The calcite was prepared from chicken eggshells by heating and activation methods. It was modified by mixing it with commercial activated carbon as a new adsorbent. XRD and FTIR were used to characterize the adsorbents. Light naphtha fuel from the Al-Diwaniyah refinery, with a sulfur concentration of 776 ppm, was used in batch adsorption studies. Various operation conditions that affect the adsorption process were studied such as temperature (20–40 °C), weight of the adsorbent (1-3 g), and contact time (15–45 min) at constant mixing speed (300 rpm). In this study, the Minitab Program-Box-Behnken design was used to design experiments in batch adsorption studies of light naphtha, which is considered more straightforward and accurate because it shows the effect of each dependent factor on the adsorption efficiency and removal ratio. Results and analysis showed that the increase in temperature, the amount of adsorbent, and contact time would increase the removal efficiency. The analysis of adsorption equilibrium isotherms shows that the experimental data follows the Freundlich isotherm model for adsorbents. According to the results of the study, the highest removal percentages of sulfur content of light naphtha using calcite and modified calcite were 61% and 79%, respectively.