Method for desulfurizing diesel fuel

Abstract

Alumina/NiO/ZnO and Alumina/ZnO are synthesized via a novel modified hydrothermal method and investigated for the desulfurization activities. Sulfur compounds such as thiophene, benzothiophene (BT) and dibenzothiophene (DBT) are tested for their removal from model diesel fuel. The prepared composite materials were examined by the means of N.sub.2-adsorption, X-ray diffraction and Fourier transform infrared spectroscopy.

Claims

1. A method for desulfurizing diesel fuel, comprising: passing the diesel fuel through a fluidized bed reactor, a transport bed reactor, or a moving bed reactor containing an adsorbent, wherein the adsorbent comprises an alumina/NiO/ZnO material, contacting the alumina/NiO/ZnO material with the diesel fuel to adsorb one or more sulfur compounds present in the diesel fuel on the alumina/NiO/ZnO material; wherein the alumina/NiO/ZnO material has a surface area of 10-15 m.sup.2/g.

2. The method of claim 1 wherein the sulfur compounds are selected from the group consisting of dibenzothiophene, benzothiophene, and thiophene.

3. The method of claim 1 wherein the method has an adsorption time of 50 minutes.

4. The method of claim 1 wherein the one or more sulfur compounds are adsorbed at an adsorption rate that follows a pseudo second-order reaction rate.

5. The method of claim 1 wherein a concentration of the one or more sulfur compounds in the diesel fuel is 450-650 mg/L.

6. The method of claim 1 wherein the alumina/NiO/ZnO material is contacted with the diesel fuel at room temperature.

7. The method of claim 1 wherein the alumina/NiO/ZnO material has a pore volume of 0.1-0.8 cm.sup.3/g.

8. The method of claim 1 wherein the/NiO/ZnO material has an adsorption average pore width of 500-600 .

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) A more complete appreciation of the disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

(2) FIG. 1 is an XRD for alumina/NiO/ZnO;

(3) FIG. 2 is a graph of the percentage removal of thiophene, BT and DBT on alumina\NiO\ZnO and alumina/ZnO;

(4) FIG. 3 is a graph of the effect of alumina/NiO/ZnO composite dosages on the adsorption of thiophene, BT and DBT;

(5) FIG. 4 is a graph of the percentage removal of thiophene, BT and DBT;

(6) FIG. 5 is a graph of the effect of adsorption time on the adsorptive capacity of alumina/NiO/ZnO at ambient conditions;

(7) FIG. 6 is a graph of the first order Pseudo kinetics for adsorption of thiophene, BT and DBT by alumina/NiO/ZnO; and

(8) FIG. 7 is a graph of the second order Pseudo kinetics for adsorption of thiophene, BT and DBT by alumina/NiO/ZnO.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(9) Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views.

(10) The present invention relates to a hydrothermal method for obtaining an alumina/NiO/ZnO material. The hydrothermal method may further include thermal, chemical, and mechanical treatments to obtain the desired material.

(11) First, a metal oxide is dispersed in a solution. The following can include one or more of (1) a refractory inorganic oxide such as an alumina, a magnesia, a titania, a zirconia, a chromia, a zinc oxide, a thoria, a boria, a silica-alumina, a silica-magnesia, a chromia-alumina, an alumina-boria, and a silica-zirconia; (2) a ceramic, a porcelain, and a bauxite; (3) a silica, a silica gel, a silicon carbide, a clay and a synthetically prepared or naturally occurring optionally acid-treated silicate; (4) a crystalline zeolitic aluminosilicate, such as an X-zeolite, a Y-zeolite, a mordenite, and an L-zeolite, either in hydrogen form or preferably in nonacidic form; and (5) a non-zeolitic molecular sieve, such as an aluminophosphate or a silico-alumino-phosphate. Preferably, the metal oxide is alumina (aluminium (III) oxide) with the chemical composition of Al.sub.2O.sub.3. A suitable alumina material may include a crystalline alumina known as the gamma-, eta-, and theta-alumina, with gamma- or eta-alumina being the most preferred. Alumina is dispersed in a solution comprising water and a hydrocarbon based molecule with a single OH functional group (e.g. an alcohol compound). The alcohol compound includes but is not limited to methanol (CH.sub.3CH.sub.2OH), propanol (CH.sub.3CH.sub.2CH.sub.2OH), butanol (C.sub.4H.sub.9OH), pentanol (C.sub.5H.sub.11OH), hexanol (C.sub.6H.sub.13OH), heptanol (CH.sub.3(CH.sub.2).sub.6OH), octanol (CH.sub.3(CH.sub.2).sub.7OH), nonanol (CH.sub.3(CH.sub.2).sub.8OH), decanol (C.sub.10H.sub.21OH) and any isomers thereof. Preferably, the alcohol compound is ethanol.

(12) The metal oxide may be added to the solution at a mass range of 0.01-15.0 g, 2.0-10.0 g, and 3-8 g per a volume of solution in the range of 5-30 mL, 8-20 mL or 12-15 mL. Preferably, 5.0 g of the metal oxide is added to a solution containing a volume of 10 mL. The water and alcohol-containing solution may be prepared in a volume to volume (water to alcohol) ratio of 10:1, 5:2 and 1:1. Preferably, the water to alcohol ratio is a 1:1 volume ratio. Preferably the alcohol is at least 100%, 20%, 30%, 40%, or 50% in water based on the total amount of water and alcohol. Preferably, the alcohol is 50% in water. Further, the solution contains a mass concentration of metal oxide in the range of 0.01-0.5 g/mL. Preferably, the mass concentration of the metal oxide in the water and alcohol solution is 0.5 g/mL. As a separate step, a zinc compound and a nickel compound, e.g., Zn(NO.sub.3).sub.2.6H.sub.2O and Ni(NO.sub.3).sub.2.6H.sub.2O, are mixed to form a solution. Other Zn compounds include zinc carbonate (ZnCO.sub.3), zinc sulfate (ZnSO.sub.4) and zinc chloride (ZnCl.sub.2). Zn(NO.sub.3).sub.2.6H.sub.2O is added in the range of 1-10 g, 2-8 g, and 3-6 g per a volume of solution in the range of 20-100 mL, 30-80 mL, or 35-50 mL. Preferably 5 g of Zn(NO.sub.3).sub.2.6H.sub.2O is added to the solution containing a volume of 40 mL. Ni(NO.sub.3).sub.2.6H.sub.2O is added in the range of 0.1-5 g, 0.5-4 g, and 0.8-3 g. Preferably 2 g of Ni(NO.sub.3).sub.2.6H.sub.2O is added in the solution.

(13) The mixed solution of Zn(NO.sub.3).sub.2.6H.sub.2O and Ni(NO.sub.3).sub.2.6H.sub.2O is then mixed with an aqueous solution. Adding the Zn(NO.sub.3).sub.2.6H.sub.2O and Ni(NO.sub.3).sub.2.6H.sub.2O to an aqueous solution dissolves both the Zn(NO.sub.3).sub.2.6H.sub.2O and Ni(NO.sub.3).sub.2.6H.sub.2O. Further, the solution contains a mass concentration in the range of 0.01-0.5 g/mL. Preferably, the mass concentration of the Zn(NO.sub.3).sub.2.6H.sub.2O and Ni(NO.sub.3).sub.2.6H.sub.2O in the aqueous solution is 0.175 g/mL.

(14) Next, the Zn(NO.sub.3).sub.2.6H.sub.2O and Ni(NO.sub.3).sub.2.6H.sub.2O in the aqueous solution is mixed with the dissolved metal oxide-containing solution. Ammonia or another base is added to the solution to maintain the pH of the liquid mixture. The volume of ammonia added is such that the pH of the mixed solution is no less than 6. The solution is mixed to create a homogeneous mixture of the compounds. Manual methods and mechanical methods may be used to mix the solution. Manual methods of mixing may be used to mix the solution including but not limited to swirling the solution by hand and by placing a magnetic stir bar in the solution and stirring with a magnetic stir plate. Mechanical methods include but are not limited to sonicating the solution using an ultrasonic bath or an ultrasonic probe or ultrasonicating the solution. Preferably, ultrasonication is used. Ultrasonication in the presence of a solvent enhances the absorbivity of the Zn(NO.sub.3).sub.2.6H.sub.2O and Ni(NO.sub.3).sub.2.6H.sub.2O nanoparticles by improving their dispersion within the solvent and optimizes conditions for removal of the sulfur-containing compounds once they react with the solution during desulfurization. The solution is ultrasonicated at a frequency of >20 kHz, more preferably between 20-30 kHz. The ultrasonicator functions at a power within the range of 100-1500 W, 200-1300 W, or 300-800 W. More preferably, the ultrasonicator functions at a power between 300-800 W. The solution is ultrasonicated for a time period ranging from 30-100 minutes, 40-80 minutes, and 50-65 minutes. Preferably the solution is ultrasonicated for 60 minutes.

(15) Following the method of mixing, the solution undergoes a heating treatment. The solution is heated at a temperature range of 50-98 C., 60-95 C., or 70-90 C. over a time period ranging from 10-20 hours, 11-18 hours, or 12-15 hours. Preferably the solution is heated at 90 C. and over a time period of 12 hours.

(16) Following the heating treatment, the sample is dried. Methods of drying include allowing the sample to air dry over a time period of no more than twelve hours and drying the sample in an oven. Preferably, the sample is dried in an oven at a temperature ranging from 20-80 C., 30-70 C., and 40-55 C. Preferably the sample is heated at 50 C.

(17) Following drying, the sample undergoes calcination. Calcination can be carried out in shaft furnaces, rotary kilns, multiple hearth furnaces, and/or fluidized bed reactors. Calcination is conducted over a time period of 1-4 hours, 1.25-3 hours, or 1.5-2.5 hours at a temperature ranging from 300-600 C., 325-650 C., or 350-500 C. Preferably calcination is conducted over 2 hours at a temperature ranging from 350-500 C. Calcination allows for thermal treatment of the sample in which the desired alumina/NiO/ZnO material is separated from the organic material of the sample.

(18) The resulting material contains a mixture of a metal oxide/NiO/ZnO, preferably alumina/NiO/ZnO. The preferred material composition includes but is not limited to the following compositional ranges: 5-25% alumina, 50-95% NiO, and 0-25% ZnO or 10-50% alumina, 50-100% NiO, and 40-50% ZnO or 15-30% alumina, 70-95% NiO, and 15-30% ZnO or 5-20% alumina, 80-95% NiO, and 5-20% ZnO or 0-20% alumina, 80-100% NiO, and 0-20% ZnO. The surface area of the alumina/NiO/ZnO material is in the range of 10-15 m.sup.2/g, 11-14 m.sup.2/g, and 12-13 m.sup.2/g. Preferably the surface area of the alumina/NiO/ZnO material is about 12.4 m.sup.2/g. The pore volume as defined as the spaces in a material, and the fraction of the volume of voids over the total volume of the alumina/NiO/ZnO is in the range of 0.05-1 cm.sup.3/g, 0.1-0.8 cm.sup.3/g, and 0.15-0.4 cm.sup.3/g. Preferably, the pore volume of the alumina/NiO/ZnO is about 0.162 cm.sup.3/g. The adsorption average pore width of the alumina/NiO/ZnO material is 500-600 , 510-590 , and 515-530 . Preferably, the adsorption average pore width of the alumina/NiO/ZnO material is 520 .

Example: Preparation of Alumina/NiO/ZnO Adsorbent

(19) The composite adsorbent (alumina/NiO/ZnO) was prepared via thermal precipitation method. One example is presented here. 5.0 g of alumina was dispersed in water and ethanol 1:1 (v:v) solution. On the other side, a mixed solution of 5.0 g of Zn(NO.sub.3).sub.2.6H.sub.2O and 2.0 g of Ni(NO.sub.3).sub.2.6H.sub.2O was dissolved in water. The solution was added into the dispersed alumina solution and mixed under sonication for 60 min followed by heating at 90 C. for 12 h. Then, it was cooled to room temperature and filtered. The sample was finally dried in oven at 50 C. Calcination of the material was conducted for 2 h at 350-500 C. Different ratio of the three components were investigated.

(20) In another embodiment of the invention, a hydrothermal method is used for obtaining an alumina/ZnO material. The hydrothermal method may further include thermal, chemical, and mechanical treatments to obtain the desired material.

(21) First, a metal oxide is dispersed in a solution. The following The following can include one or more of (1) a refractory inorganic oxide such as an alumina, a magnesia, a titania, a zirconia, a chromia, a zinc oxide, a thoria, a boria, a silica-alumina, a silica-magnesia, a chromia-alumina, an alumina-boria, and a silica-zirconia; (2) a ceramic, a porcelain, and a bauxite; (3) a silica, a silica gel, a silicon carbide, a clay and a synthetically prepared or naturally occurring optionally acid-treated silicate; (4) a crystalline zeolitic aluminosilicate, such as an X-zeolite, a Y-zeolite, a mordenite, and an L-zeolite, either in hydrogen form or preferably in nonacidic form; and (5) a non-zeolitic molecular sieve, such as an aluminophosphate or a silico-alumino-phosphate. Preferably, the metal oxide is alumina (aluminium (III) oxide) with the chemical composition of Al.sub.2O.sub.3. A suitable alumina material may include a crystalline alumina known as the gamma-, eta-, and theta-alumina, with gamma- or eta-alumina being the most preferred. Alumina is dispersed in a solution comprising water and a hydrocarbon based molecule with a single OH functional group (e.g. an alcohol compound). The alcohol-containing compound includes but is not limited to methanol (CH.sub.3CH.sub.2OH), propanol (CH.sub.3CH.sub.2CH.sub.2OH), butanol (C.sub.4H.sub.9OH), pentanol (C.sub.5H.sub.11OH), hexanol (C.sub.6H.sub.13OH), heptanol (CH.sub.3(CH.sub.2).sub.6OH), octanol (CH.sub.3(CH.sub.2).sub.7OH), nonanol (CH.sub.3(CH.sub.2).sub.8OH), decanol (C.sub.10H.sub.21OH) and any isomers thereof. Preferably, the alcohol compound is ethanol.

(22) The metal oxide may be added to the solution at a mass range of 0.01-15.0 g, 2.0-10.0 g, and 3-8 g per a volume of solution in the range of 5-30 mL, 8-20 mL or 12-15 mL. Preferably, 5.0 g of the metal oxide is added to a solution containing a volume of 10 mL. The water and alcohol-containing solution may be prepared in a volume to volume (water to alcohol) ratio of 10:1, 5:2 and 1:1. Preferably, the water to alcohol ratio is a 1:1 volume ratio. Preferably the alcohol is at least 10%/a, 20%, 30%, 40%, or 50% in water. Preferably, the alcohol is 50% in water based on the total amount of water and alcohol. Further, the solution contains a mass concentration of metal oxide in the range of 0.01-0.5 g/mL. Preferably, the mass concentration of the metal oxide in the water and alcohol solution is 0.5 g/mL.

(23) As a separate step, a zinc compound, e.g. Zn(NO.sub.3).sub.2.6H.sub.2O, is dissolved in water. Other Zn compounds include zinc carbonate (ZnCO.sub.3), zinc sulfate (ZnSO.sub.4) and zinc chloride (ZnCl.sub.2). Zn(NO.sub.3).sub.2.6H.sub.2O is added in the range of 1-10 g, 2-8 g, and 3-6 g per a volume of solution in the range of 20-100 mL, 30-80 mL, or 35-50 mL. Preferably 5 g of Zn(NO.sub.3).sub.2.6H.sub.2O is added to the solution containing a volume of 40 mL. Preferably 5 g of Zn(NO.sub.3).sub.2.6H.sub.2O is added to water. The volume of water is such that the pH of the mixed solution of Zn(NO.sub.3).sub.2.6H.sub.2O and water is no less than 6.

(24) Next, the Zn(NO.sub.3).sub.2.6H.sub.2O in the aqueous solution is mixed with the dissolved metal oxide-containing solution. The solution is mixed to create a homogeneous mixture of the compounds. Manual methods and mechanical methods may be used to mix the solution. Manual methods of mixing may be used to mix the solution including but not limited to swirling the solution by hand and by placing a magnetic stir bar in the solution and stirring with a magnetic stir plate. Mechanical methods include but are not limited to sonicating the solution using an ultrasonic bath or an ultrasonic probe or ultrasonicating the solution. Preferably, ultrasonication is used. Ultrasonication in the presence of a solvent enhances the absorbivity of the Zn(NO.sub.3).sub.2.6H.sub.2O and nanoparticles by improving their dispersion within the solvent and optimizes conditions for removal of the sulfur-containing compounds once they react with the solution during desulfurization. The solution is ultrasonicated at a frequency of >20 kHz, more preferably between 20-30 kHz. The ultrasonicator functions at a power within the range of 100-1500 W, 200-1300 W, or 300-800 W. More preferably, the ultrasonicator functions at a power between 300-800 W. The solution is ultrasonicated for a time period ranging from 30-100 minutes, 40-80 minutes, and 50-65 minutes. Preferably the solution is ultrasonicated for 60 minutes.

(25) Following the method of mixing, the solution undergoes a heating treatment. The solution is heated at a temperature range of 50-98 C., 60-95 C., or 70-90 C. over a time period ranging from 10-20 hours, 11-18 hours, or 12-15 hours. Preferably the solution is heated at 90 C. and over a time period of 12 hours.

(26) Following the heating treatment, the sample is dried. Methods of drying include allowing the sample to air dry over a time period of no more than twelve hours and drying the sample in an oven. Preferably, the sample is dried in an oven at a temperature ranging from 20-80 C., 30-70 C., and 40-55 C. Preferably the sample is heated at 50 C.

(27) Following drying, the sample undergoes calcination. Calcination can be carried out in shaft furnaces, rotary kilns, multiple hearth furnaces, and/or fluidized bed reactors. Calcination is conducted over a time period of 1-4 hours, 1.25-3 hours, or 1.5-2.5 hours at a temperature ranging from 300-600 C., 325-650 C., or 350-500 C. Preferably calcination is conducted over 2 hours at a temperature ranging from 350-500 C. Calcination allows for thermal treatment of the sample in which the desired alumina/NiO/ZnO material is separated from the organic material of the sample.

(28) The resulting material contains a mixture of a metal oxide/ZnO, preferably alumina/ZnO. The preferred material composition includes but is not limited to the following compositional ranges: 1-25% alumina and 75-99% ZnO or 1-50% alumina and 50-99% ZnO or 25-50% alumina and 50-75% ZnO or 50-75% alumina and 25-50% ZnO or 10-20% alumina and 80-90% ZnO. The surface area of the alumina/ZnO material is in the range of 10-20 m.sup.2/g, 11-18 m.sup.2/g, and 12-17 m.sup.2/g. Preferably the surface area of the alumina/ZnO material is 12.4 m.sup.2/g. The pore volume as defined as the spaces in a material, and the fraction of the volume of voids over the total volume of the alumina/ZnO is in the range of 0.05-1 cm.sup.3/g, 0.1-0.8 cm.sup.3/g, and 0.15-0.4 cm.sup.3/g. Preferably, the pore volume of the alumina/ZnO is about 0.211 cm.sup.3/g. The adsorption average pore width of the alumina/ZnO material is 500-600 , 510-590 , and 515-550 . Preferably, the adsorption average pore width of the alumina/ZnO material is 540 .

Example: Preparation of Alumina/ZnO Adsorbent

(29) The alumina/ZnO composite adsorbent was prepared via thermal precipitation method. This was realized by dispersion of 5.0 g of alumina in water and ethanol 1:1 (v:v) solution. On the other side, a mixed solution of 5.0 g of Zn(NO.sub.3).sub.2.6H.sub.2O was dissolving in water and its pH was controlled at higher than 6. The solution was added into the dispersed alumina solution and mixed under sonication for 60 min followed by heating at 90 C. for 12 h. Then, it was cooled to room temperature and filtered. The sample was finally dried in oven at 50 C. Calcination of the material was conducted for 2 h.

(30) The characterizations of composite adsorbents were performed by using different techniques. Specific surface areas and pore volumes were determined by N.sub.2 adsorption (BET). The characterization of the surface chemistry of the adsorbents and the surface morphology were performed X-ray diffraction spectroscopy (XRD) and Fourier Transform Infrared spectroscopy (FT-IR). Nitrogen sorption isotherms were performed at liquid nitrogen temperature (196 C.) on a Micromeritics ASAP 2020 volumetric instrument to determine surface area (BET), pore volume and pore size distribution in the tested sorbents. The FT-IR analyses were done on the powdered samples with KBr addition. Spectra were recorded using a Nicolet 6700 spectrometer equipped with OMNIC program and (DTGS Br) detector. The spectra of the samples were recorded in transmission mode and the wavenumber range (4000-400 cm.sup.1). FTIR spectra were obtained by adding 64 scans with a resolution of 2 cm.sup.1 and corrected for the background noise. X-ray diffraction data were obtained on a Shimadzu XRD Model 6000 diffractometer using K radiation of Cu and was operated at 40 kV and 30 mA. EDX patterns were obtained using (FESEM, Nova NanoSEM Ultra-High Resolution) operating at 20 kV with different magnification powers.

(31) In another embodiment of the invention, the alumina/NiO/ZnO and alumina/ZnO materials are used as sorbents to adsorb sulfur-containing compounds by a method of desulfurization. The adsorption of sulfur-containing compounds includes but are not limited to dibenzothiopene (DBT), benzothiopene (BT), and thiopene.

(32) In the method, the sulfur-containing compounds are adsorbed from model diesel fuel. A model diesel fuel solution is prepared by dissolving the sulfur containing compounds into a solvent. The solvent is prepared by mixing an aromatic-containing compound with an alkane. Preferably, the aromatic-containing compound contains at least one six-membered hydrocarbon ring with a C.sub.1-C.sub.6 alkyl group selected from the group consisting of methyl (CH.sub.3), ethyl (C.sub.2H.sub.5), propyl (C.sub.3H.sub.7), butyl (C.sub.4H.sub.9), pentyl (C.sub.5H.sub.11), or hexyl (C.sub.6H.sub.13) where said alkyl unit is attached to one of the carbon units of said hydrocarbon ring. Preferably, the alkyl group is methyl and more preferably the aromatic solvent used is toluene. The alkane is selected from a C.sub.1-C.sub.6 group consisting of methane (CH.sub.4), ethane (C.sub.2H.sub.6), propane (C.sub.3H.sub.8), butane (C.sub.4H.sub.10), pentane (C.sub.5H.sub.12), and hexane (C.sub.6H.sub.14). More preferably, the alkane used is hexane.

(33) Once the solvent is mixed, different amounts of the sorbents are introduced to a model diesel fuel solution. Preferably, 100-300 mg, 110-250 mg, and 150-200 mg of DBT, BT and thiopene is used per about 4 mL of solvent. The desired sorbent is then introduced into the model fuel solution containing the sulfur-containing compounds DBT, BT, and thiopene with an initial concentration in the range of 450-650 mg/L, 500-600 mg/L, or 550-595 mg/L. Preferably, the initial concentration of sulfur-containing compounds in the model diesel fuel is 577 mg/L.

(34) The resultant mixture is then induced into equilibrium by shaking at room temperature. Samples are then taken from the mixture at time intervals of 0, 10, 30, 50, and 70 minutes of time to be analyzed by GC-SCD method.

(35) The alumina/NiO/ZnO sorbent proved to be more effective in removing sulfur-containing compounds in the process of desulfurization when compared to the alumina/ZnO sorbent. The alumina/NiO/ZnO has a smaller surface area and pore volume, but the presence of nickel enhances the efficiency of the particular sorbent in desulfurization.

(36) The adsorption of DBT, BT and thiophene from model diesel on the newly developed sorbents was performed using batch modes. Different amounts, in the range between 0.1 to 1 g of adsorbent were introduced into 50 mL of the model fuel solution. The total DBT, BT and thiophene initial concentrations was 577 mg/L, prepared by dissolving 197 mg DBT, 190 mg BT and 190 mg Thiophene in 1 L solvent (762 ml toluene+238 ml hexane). Thus, the amount of sulfur calculated in the fuel was 34.28 ppm, 45.39 ppm and 72.43 ppm, respectively. The resulting mixture was continuously shaken at room temperature until equilibrium. Aliquots were taken from the system at the pre-determined time intervals and analyzed by GC-SCD method.

(37) The percentage removal of sulfur was calculated using the following Equation:

(38) $\%\mathrm{Removal}=\frac{C_o-C_e}{C_o}100$
Where C.sub.0 is the initial sulfur concentration (mg/L), Ce is the sulfur concentration (mg/L) at equilibrium.
The adsorption (qe, mg/g) at equilibrium, was calculated by

(39) $q_e=\left(C_o-C_e\right)\frac{V}{w}$

(40) Where, Co (mg/L) and Ce (mg/L) are the sulfur compound concentrations contained in the initial solution and at equilibrium, respectively; V (L) is the volume of the fuel solution; and w (mg) represents the weight of adsorbents.

(41) FT-IR spectroscopy is a useful tool for showing the presence of functional groups in organic compounds. The absorption band at 435 cm.sup.1 is the characteristic band of NiO stretching vibrational mode, and absorption bands at 3400 cm.sup.1 represent OH mode; those at 2900 cm.sup.1 are CH mode; those at 1380 and 1600 cm.sup.1 are the asymmetric and symmetric CO stretching modes of zinc acetate; and that at 490 cm.sup.1 is the stretching mode of ZnO.

(42) For comparing 1 g from each adsorbent was added to two flasks contain 577 ppm sample and stirred for 80 minutes. The percent removal of thiophene, BT and DBT using alumina\NiO\ZnO and Alumina\ZnO adsorbents found to be significant. Although, alumina\ZnO has larger BET surface area and pore volume, it is clear that Alumina\NiO\ZnO exhibited higher adsorption capacity for the three compounds which means that, the metal species located contribute to enhanced interactions. These results agree with previously reported data that Nickel has an affinity to the organic sulfur compounds and it is the active sites on Ni/ZnO for desulfurization process. FIG. 1 shows a typical Alumina\NiO\ZnO x-ray diffractogram of composite.

(43) The results indicate that the amount of these compounds adsorbed by Alumina\NiO\ZnO is increased with the increasing amount of the adsorbent. Experimental results showed that the percent removal increased with increasing the amount of adsorbent. This can be attributed to the increase in surface area resulting from the increase in adsorbent mass or higher adsorption sites. Percentage removal of thiophene, BT and DBT on Alumina\NiO\ZnO and Alumina\ZnO is given in FIG. 2, where FIG. 2 is a graph illustrating the percentage removal of thiophene, BT and DBT on Alumina\NiO\ZnO and Alumina\ZnO (dosage 1 g, time 50 min, initial concentration 190, 190 and 197 ppm respectively).

(44) FIG. 3 is a graph illustrating the effect of Alumina\NiO\ZnO composite dosages on the adsorption of thiophene, BT and DBT (with initial concentration 190, 190 and 197 ppm respectively) in 50 min. time.

(45) The sulfur adsorbed increased with time in the first 50 min as shown in FIG. 4, where FIG. 4 illustrates a graph of the percentage removal of thiophene, BT and DBT, versus time on 1 g Alumina \NiO\ZnO (with initial concentration 190,190 and 197 ppm respectively). After that, the adsorbed amount almost did not change, indicating the equilibrium was reached. The fast adsorption at the initial stages may be due to availability of the uncovered surface and active sites on the adsorbent surface.

(46) The effects of adsorption time on the adsorptive capacity of Alumina\NiO\ZnO composite at ambient conditions were also studied as shown in FIG. 5, where FIG. 5 illustrates the effect of adsorption time on the adsorptive capacity of Alumina\NiO\ZnO at ambient conditions, employing a model fuel/adsorbent ratio of 50 mL/1 g. The sulfur absorbed increased with time in the first 50 min. After that, no significant adsorption was observed, indicating the equilibrium was reached and the equilibrium adsorption capacity was 6.5 mg-S/g-A (milligram of sulfur per gram of adsorbent).

(47) Three kinetic models were applied for analysis of experimental kinetic data. The pseudo-first order, second-order kinetics and intraparticle diffusion model.

(48) The pseudo-first-order equation was first given by Lagergrer. The Lagergren rate equation is expressed in the following equation:
ln(q.sub.eq.sub.t)=1nq.sub.ek.sub.1t
where, qe (mg/g) and qt (mg/g) are the amounts of analyte adsorbed at equilibrium and time t (min), respectively; and k.sub.1 (min.sup.1) is the rate constant of the Lagergren-first-order kinetics model.

(49) The k.sub.1 and qe were calculated from the slope and intercept The plot of ln(qeqt) versus t, respectively. The calculated qe are lower than the experimental values. As well as, The R.sup.2 of the pseudo first order model are lower than the pseudo second order model, indicating that the adsorption of thiophene, BT and DBT on Alumina\NiO\ZnO does not obey the pseudo first order kinetic. The data is shown in FIG. 6, where FIG. 6 illustrates the first order Pseudo kinetics for adsorption of thiophene, BT and DBT by Alumina\NiO\ZnO.

(50) The pseudo-second-order kinetics can be expressed as the following equation:

(51) $\frac{t}{q_t}=\frac{1}{k_2{q}_e^2}+\frac{t}{q_e}$

(52) Where qt is the amount of adsorption THIO, BT and DBT (mg/g) at time t (min) and k.sub.2 (g/(mg min)) is the adsorption rate constant of pseudo-second-order adsorption. The slope and intercept of the linear plots of t/qt against t yield the values of 1/qe and 1/k.sub.2qe.sup.2. Where k.sub.2qe.sup.2 (mg/g.Math.min) term is the initial adsorption rate at t=0.

(53) The k.sub.2 and qe can be obtained from the slope and intercept of plot of t/qt versus t. The pseudo second order model is based on the assumption that the rate limiting step may be chemisorption which involves valence forces by sharing or electron exchange between the adsorbent and the adsorbate.

(54) The maximum adsorption capacities qe calculated from the pseudo second order model are in accordance with the experimental values and higher correlation coefficient (R.sup.2) indicate that the adsorption obeys a pseudo second order model. FIG. 7 displays the results obtained from pseudo-second-order model.

(55) In the Intra-particle diffusion model, the time dependent intra-particle diffusion of components is described by Weber's kinetic model.

(56) The experimental data for the adsorption of thiophene, BT, DBT onto Alumina\NiO\ZnO were fitted by the intraparticle diffusion model to identify the mechanism involved in the sorption process, which model is expressed as:
q.sub.t=k.sub.idt.sup.1/2+C
Where C is the intercept and k.sub.id is the intraparticle diffusion rate constant (mg/g h.sup.1/2) which can be evaluated from the slope of the linear plot of qt versus t1/2.

(57) The calculated intraparticle diffusion coefficient k.sub.id values are listed in the Table 1, as shown below.

(58) TABLE-US-00001 Pseudo-first order Pseudo-second order Intraparticle q.sub.e,exp qe, qe, diffusion model compound (mg/g) k1 cal R.sup.2 k2 cal R.sup.2 ki C R.sup.2 THIO 6.49 0.033 1.12 0.976 0.107 6.6 0.999 0.113 5.52 0.954 BT 5.73 0.035 1.66 0.992 0.05 5.8 0.999 0.2 3.99 0.983 DBT 5.83 0.039 2.18 0.961 0.034 6.2 0.998 0.28 3.5 0.922

(59) The larger the intercept, the greater the contribution of the surface sorption in the rate controlling step. If the regression of qt versus t.sup.1/2 is linear and passes through the origin, then intraparticle diffusion is the sole rate-limiting step. However, the linear plots at each compound did not pass through the origin. This indicates that the intraparticle diffusion was not only rate controlling step.

(60) A method is reported for preparing alumina\NiO\ZnO and Alumina\ZnO for desulfurization and removal of thiophene, benzothiophene (BT) and dibenzothiophene (DBT) from model diesel at ambient conditions. Alumina\NiO\ZnO has higher adsorption capacity which may be attributed to the present of NiO and zinc oxide and the interaction between the components. The results suggest that Alumina loaded with transition metal oxides may prove to be promising adsorbents for deep desulphurization processes. Further, the kinetic studies indicated that the adsorption process of Thiophene, BT and DBT on Alumina\NiO\ZnO follows the pseudo-second-order.

(61) Thus, the foregoing discussion discloses and describes merely exemplary embodiments of the present invention. As will be understood by those skilled in the art, the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the disclosure of the present invention is intended to be illustrative, but not limiting of the scope of the invention, as well as other claims. The disclosure, including any readily discernible variants of the teachings herein, define, in part, the scope of the foregoing claim terminology.