Effect of Cationic Surfactant in the Synthesis Process of Nano γ-Alumina for Petroleum Industry Application

Nanotechnology is widely used in industries, including catalyst synthesis for oil and gas industries to enhance and perform new Characteristics of materials. Cetyl tri methyl ammonium bromide (CTAB) cationic surfactant was used in the synthesis of spherical nanostructured γ-alumina to enhance the morphology of the prepared nano gamma alumina which is used as a catalyst support in the naphtha reforming process. The preparation was carried out by co-precipitation method by adding drop wise of ammonium hydroxide solution and aluminum nitrate nonahydrate solution simultaneously to a solution of surfactant medium, PH and temperature of reaction were kept at 8 and 30 cᵒ respectively. The gamma alumina obtained were characterized by X-Ray Diffraction (XRD), nitrogen adsorption-desorption analysis (ASAP 2020, Micromeretics) and atomic force microscope (AFM). The sample of synthesized gamma alumina with the CTAB cationic surfactant showed that surface are (314 m2/g), pore volume (0.37 cm3/g), and pore size (3.6 nm).


Introduction
Aluminum oxide is useful in petroleum industry because of their excellent properties, such as high abrasion resistance, good insulation, high hardness, excellent dielectric strength at high voltage, thermal stability with a melting point of 2050 c o , and high resistance to chemical attack. As a result of its own textural properties and morphology, gamma alumina is commonly used as a catalyst support and adsorption. This is due to its improved properties, which include high thermal stability, surface area, pore volume, pore size, amphoteric and hydrolytic properties [1]. gamma alumina (γ -Al 2 O 3 ) is possibly the most important transition aluminas known, with applications as a catalyst and catalyst support in the oil and gas industries. This oxide's usefulness can be attributed to a favorable combination of its textural properties, such as surface area, pore volume, and pore size distribution, and its acidity and basicity properties, which are primarily related to surface chemical components, structure, and phase composition. as fuel with varies surfactants. Gamma alumina has a fairly uniform spherical morphology with a lower size distribution of (40-60 nm). The specific surface area obtained was (160-240 m 2 /g) [6]. Wen Qian Jiao prepared mesoporous gamma alumina by using Al(NO 3 ) 3 .9H 2 O and NaAlO 2 as aluminum sources, and a template of cationic and anionic surfactants (CTAB) and dodecyl sodium sulfate (SDS) by using cationic-anionic double hydrolysis (CADH) method. The obtained gamma Al 2 O 3 made up of nanoparticles with lengths ranging from 50 to 100 nm.
Other characteristics include a high specific surface area (261 m 2 /g), a large pore volume (0.79 cm 3 /g), and a large pore size (12.1 nm) with a narrow pore size distribution [7]. Ming Bo Yue et al synthesized -alumina using CTAB as a surfactant, Al(NO 3 ) 3 .9H 2 O and NaAlO 2 as aluminum sources, citric acid and sodium citrate as structure direct agents, the resulting mesoporous gamma alumina with high specific surface area (398 m 2 /g) and large pore volume (0.59 cm 3 /g) [8]. Ming Bo Yue et al. also synthesized mesoporous alumina using (CTAB) and structure direct agents like sodium tartrate, citrate, or succinate. Aluminium Sulfate Octadecahydrate Al 2 (SO 4 ) 3 .18H2O as an aluminum source, and urea as a precipitating agent.
For the high importance of gamma-alumina in the preparation of catalysts that are used in the many petroleum industries. moreover, nano gamma-alumina has unique specifications that were synthesized by the Co-precipitation method and characterized it to achieve this goal.

Experimental Procedure of Preparation:
Nano γ-Al 2 O 3 was synthesized as follows: hours. Nano Gamma alumina was obtained from calcination powder for 2 hours at 550°C at a rate of 10° C/min.

Results and Discussions:
The synthesized materials have been characterized by XRD (x-ray diffraction), AFM (atomic force microscope), and N2 adsorption-desorption. Apparently spherical nano-sized particles were obtained with crystallite size in the range (nm) by peaks broadening calculation.

XRD Patterns:
The XRD patterns of all samples shown below in (Figure 2  The difference between values examined by AFM and XRD were illustrated in Table (2) i.e.
due to the principle of measuring the AFM would be more accurate than XRD results.

N 2 Physisorption Characterization
Catalytic performance was examined using Nitrogen adsorption isotherm at boiling temperature  to determine catalyst surface area and porous texture. According to IUPAC (International Union of Pure and Applied Chemistry) classification all synthesized samples were in mesopous (IV type) [12]. BET (Brunauer, Emmet and Teller) specific surface areas and pore volume were measured with an automatic sorptometer on a Micromeritics ASAP 2020 apparatus. Surface area and pore volume obtained were (314 m 2 /g) and (0.37 cm 3 /g) respectively at CTAB concentration of 0.005 molary (figure 4).
All results were tabulated in table (3) below, at different concentration of CTAB the optimum concentration is 0.035 M (run C) because surface area reach the best value and pore volume enlarged, above this concentration the CTAB solution tends to aggregate and surface tension be greater [13]. Also all samples were in narrow pore size distribution (figure 5).

Conclusion
Nano Gamma alumina successfully prepared by co-precipitation method in presence of CTAB as a surfactant. Essential parameters were studied in our research, isotherm behavior, surface area, pore volume, and pore size. The properties of our synthesized nano gamma alumina and the commercial one specified by Eugene et al and antos, were matches in surface area and pore size while pore volume should be more than 0.5 cm 3 /g to achieve excellent dispersion of active metals. Surface area enhancement from 234-314 m 2 /g while pore volume enlarged by approximately 13%.