Preparation of Supported Bimetallic Ce/Fe activated carbon for Desulfurization reaction

Activated carbon is loaded with 2 totally different metals: Ce and iron. The catalyst was characterised by Brunauer Emmett Teller (BET) and Fourier rework Infrared (FTIR). The discharged conditioner had the best area and pore volume of 1100 m 2 /g and 0.3 cm 3 /g, respectively.AC/Ce/Fe achieved the best kerosene adsorption performance (75%) though the lowest surface area and pore volume of 965.7608 m 2 /g and 0.39 cm 3 /g due to the acidic sites required for adsorption of sulfur compounds. Batch experiments with AC/Ce/Fe showed a high adsorption capacity. These experiments were designed by Minitab Response Surface Methodology RSM 2019. The Analysis of variance ANOVA shows that the concentration of H2O2 has most significant effect on the sulfur removal followed by reaction time and temperature, respectively. The model optimization was set its parameters additives 10 ml H2O2, temperature 80 0 C and time 5 hr.


Introduction
In recent years, rising global energy demand, stringent environmental legislation on transportation fuels and depleted oil reserves together have formed a triangle of constraints that pose significant challenges to refineries. Increased emissions in the form of SO X will increase with increased energy demand due to fuel combustion in transportation or in oil refineries.
These emissions are harmful because emitted sulfur dioxide (SO X ) can react with water in the atmosphere, forming acid rain that is harmful to soils, buildings, forests and ecosystems. Sulfur emissions also exacerbate heart disease, respiratory diseases, cause asthma, and contribute to the formation of atmospheric particles.
Crude oil and distillated petroleum contain undesirable sulfur due to the following reasons: [2]  Organic sulfur compounds can cause the emission of sulfur oxides (SO X ) as a result of the combustion of fuel used in transportation, which leads to acid rain.
 Many corrosion problems occur in pipes, pumps, and other refining units due to sulfur compounds. Sulfur emissions also cause respiratory diseases, exacerbate heart disease, cause asthma and contribute to the formation of atmospheric particles.
 In reforming process, organic sulfur compounds caused poisoning for the catalyst. Therefore, fuel desulfurization may be a terribly necessary method within the oil industry, and there's a necessity to search out new strategies that are a lot of economical and efficient and meet the expectations of environmental rules and purification requirements. many methods are applied to get rid of sulfur compounds from fuel oil, like hydrodesulfurization (HDS), extractive distillation, selective adsorption, bio desulfurization, and oxidative desulfurization (ODS).
ODS is taken into account a promising desulfurization technology as a result of it is operated at temperature and low and doesn't need the employment of hydrogen. Also, ODS will simply take away the refractory sulfur compounds due to their high lepton density. ODS method can enhance the potency of sulfur removal while not destroying and poisoning catalyst [3].
On the contrary, acetonitrile has good physical properties such as low boiling point (82 o C), so the separation of sulfones is easily achieved by distillation process [4].

Gao et al. (2018)
Studied the oxidative desulfurization process of a model fuel using oxygen as an oxidizer and CNTs/MOF-199-Mo16V2 as a catalyst. The test results indicate that the CNTs/MOF-199-Mo16V2 catalyst possesses superior catalytic activity, with a desulfurization efficiency of 98.30% obtained. Also, the CNTs/MOF-199-Mo16V2 shows excellent reusability and the catalytic efficiency is slightly reduced after 7 times recycling [5]. showed that the catalytic activity of HPA/C were found to decrease in the order of HPA: H 3 PMo12O40>H3PW12O40 >H4SiW12O40. The most active catalyst is H 3 PMo12O40/C and has exhibited 100% of benzothiophenes (BT) removal from diesel fuel at 60 °C [6].  The results indicated that the removal efficiency of DBT, BT and TH were achieved to be 97, 98, and 99%, respectively. Also, the evaluation of reusability of the heterogeneous nanocatalyst showed that the Fe2W18Fe 4 /FeTiO 3 could be reused up to five runs conveniently [9].

Experimental Work
Materials and chemicals

Oil feedstock
Kerosene is used as a feedstock with sulfur content (0.2244 wt. %) supplied by the Midland refinery /Al-Dura refinery. The physical properties of the Kerosene are illustrated in Table   (1).

Catalysts
Activated carbon AC used in the present work, mean partial size of AC was 300 mesh (0.048 mm). The AC dried in an oven at 110 0 C for 4 h to remove any moisture and stored in a desiccator. It was supplied by Central Drug House, India to the Iraqi local markets.

Chemicals
The chemical compounds that used in this study are listed in Table (2): 6-Re-flow the air at 90°C, 330 rpm for 2 hours, leave until the second day.
7-The precipitate was filtered, washed and dried at 110°C in an oven for 18 hours to remove water and salt crystallization at the pore surface.
8-The dried catalyst was calcined at 350 °C in an oven for 4 h to ensure that the metals were adequately localized on the surface of the air conditioner.

Experimental Design
In this work, the experimental work includes carrying out different experiments process by using the following operating conditions: 1-Reaction time (2, 5 and 24) hr.

Oxidative Desulfurization Process Batch Reactor
The oxidisation reaction of the sulfur compound is applied during a batch reactor. A fifty ml single-neck circular flask is employed for the reaction. The neck is connected to a vertical condenser to condense fuel vapor. The round flask is placed round the neck on a beaker full of water to confirm even heat distribution. A thermometer is placed to measure the temperature. The batch reactor is heated and mixed by a magnetic stirrer.

Oxidation of Sulfur Experimental Procedure
The raw material for oil is kerosene containing sulfur compound. The following steps are performed in each run: 1. 25 mL of feedstock is shipped to the round bottom flask along with 0.5 g of catalyst.
2. A specified amount of hydrogen peroxide is added.
3. The flask was placed in the heating mantle motor and connected to the condenser. The flow of cooling water through the condenser is ensured to prevent any evaporation of kerosene. A thermometer is inserted to measure the reaction temperature. 6. At the end of the operation, the heating mantle motor was turned off and the product material was filtered.
7. The sulfur content was tested in all the drawn samples.

Catalysts Characterization
The textural characteristics of the original and modified activated carbon are presented in Table (3).

FTIR
The FTIR spectra of all the adsorbents are appeared in Figure (

Effect of Reaction Temperature
The impact of response temperature on desulfurization effectiveness was explored for 5 h response time at 25°C, 50°C, and 80°C utilizing distinctive sums of hydrogen peroxide; (0, 1, 5, and 10) ml as appeared in Figure (3). The gotten comes about demonstrated that the oxidation of thiophene compounds and their subsidiaries was upgraded to sulfone oxide and sulfonate when the response temperature was expanded from 25°C to 80°C and the desulfurization proficiency was made strides. As seen at 25°C, desulfurization was underneath 50°C and 80°C. Expanding the response temperature improves the oxidation of lamp fuel. This may be related to the deterioration of hydrogen peroxide in parallel with an increment within the response, temperature creates hydroxyl radicals that act as a solid oxidizing specialist. The same behavior has moreover been watched by a few analysts, such as Lanju et al., 2006[19].   [20]. Similar behavior was obtained by Yanxiu et al., 2013 [21] for the oxidative desulfurization of a normal sulfur compound by the nearness of a phosphorous molybdic corrosive catalyst in which the remaining sulfur substance was found to diminish with expanding oxidation time. The response was near to harmony and the leftover sulfur substance was nearly unaltered.

Optimization Design by Using Response Surface Methodology
To investigate the intuitive impacts of parameters on desulfurization, reaction surface technique (RSM) was utilized to optimize the impacts of H2O2 concentration, temperature,    The effects of the interaction of two agents on desulfurization were illustrated by twodimensional contour plots of the three-dimensional response surface, as shown in Figure