WO2008030540A2

WO2008030540A2 - Oxidatively regenerable adsorbents for sulfur removal

Info

Publication number: WO2008030540A2
Application number: PCT/US2007/019482
Authority: WO
Inventors: Chunshan Song; Xiaoliang Ma; Shingo Watanabe; Fuxia Sun
Original assignee: The Penn State Research Foundation
Priority date: 2006-09-08
Filing date: 2007-09-07
Publication date: 2008-03-13
Also published as: WO2008030540A3

Abstract

Compositions and processes are disclosed for removing sulfur and sulfur compounds from hydrocarbon fuel feedstocks. The feedstock is contacted with a regenerable sorbent such as a compound of the formula TixCeyO2 where 0 < x/y ≤ 1 and where 0 < x ≤ l and 0 < y ≤ 1 capable of selectively adsorbing sulfur compounds present in the hydrocarbon feedstock at about 0 °C to about 100 °C such as at about 25 °C.

Description

TITLE OF THE INVENTION

Oxidatively Regenerable Adsorbents for Sulfur Removal

FIELD OF THE INVENTION The disclosed invention relates to adsorbents for removing sulfur and sulfur compounds from liquid and gaseous hydrocarbon streams such as but not limited to gasoline, jet fuel, diesel fuel, naphtha, kerosene, gas oil, vacuum gas oil and cycle oil.

BACKGROUND OF THE INVENTION

Use of ultra deep desulfurization of liquid hydrocarbon fuels such as gasoline, diesel, and jet fuel to satisfy new environmental regulations and fuel cell applications is receiving increased attention worldwide. Conventional hydrodesulfurization (HDS) technology is difficult and costly to use to remove sulfur compounds from liquid hydrocarbon fuels to levels suitable for use in fuel cells, particularly for removal of refractory sulfur compounds such as 4,6-dimethyl-dibenzothiophene (4,6-DMDBT). Several non-HDS-based desulfurization technologies for use with liquid fuels have been proposed. These technologies include adsorptive desulfurization biodesulfurization, oxidative desulfurization and extraction desulfurization. Various desulfurization processes are known or have been proposed. For example, U.S. Pat. No. 3,063,936, issued on Nov. 13, 1962 to Pearce et al. discloses that sulfur reduction can be achieved for straight-run naphtha feedstocks from 357 ppmw to 10-26 ppmw levels by hydrotreating at 380 ⁰C. using an alumina-supported cobalt molybdate catalyst. According to Pearce et al., a similar degree of desulfurization may be achieved by passing the straight- run naphtha with or without hydrogen, over a contact material comprising zinc oxide, manganese oxide, or iron oxide at 350 to 45O ⁰C. Pearce et al. propose to increase sulfur removal by treating the straight run naphtha feeds in a three- stage process in which the hydrocarbon oil is treated with sulfuric acid in the first step, a hydrotreating process employing an alumina-supported cobalt molybdate catalyst is used in the second step, and an adsorption process, preferably using zinc oxide is used for removal of hydrogen sulfide formed in the hydrotreating step as the third step. The process is said to be suitable only for treating feedstocks that are substantially free from ethylenically or acetylenically unsaturated compounds. In particular, Pearce et al. disclose that the process is not suitable for treating feedstocks, such as hydrocarbons obtained as a result of thermal cracking processes that contain substantial amounts of ethylenically or acetylenically unsaturated compounds such as full- range FCC naphtha, which contains about 30% olefins.

A challenge in development of an effective adsorptive desulfurization process is development of an adsorbent which has high sulfur capacity, high selectively to the sulfur compounds over other aromatic and olefinic compounds coexisting in the fuels, and high regenerability and stability during recycle.

A need therefore exists for adsorbents which may be effectively used in adsorptive desulfurization processes.

SUMMARY OF INVENTION

In a first aspect, the disclosed invention relates to novel metal oxide- CeO₂-based adsorbents of the formula MO-CeO₂ where M is any of Ag, Au, Ba, Be, Ca, Co, Cr, Cu, Fe, Ge, Hf, Ir, La, Mg, Mo, Ni, Os, Pb, Pd, Pt, Rh, Ru, Sc, Sn, Sr, Ti, W, Y₂, Zr and mixtures thereof such as AgO-CeO₂-based adsorbents such as Ag_{0 1}Ce₀₉O₂, AuO-CeO₂ -based adsorbents such as Au_{0 1}Ce₀₉O₂, BaO_x-CeO₂- based adsorbents where I^ x^ 2 such as Ba_{0 1}Ce₀₉O₂, BeO_x-CeO₂-based adsorbents where 1 =≤ x≤ 2 such as Be₀₁Ce₀₉O₂, CaO-CeO₂-based adsorbents such as Ca_{0 1}Ce₀₉O₂, CoO-CeO₂-based adsorbents such as Co_{0 1}Ce₀₉O₂, CrO_x- CeO₂-based adsorbents where 1 =≤ x^ 3 such as Cr₀₁Ce₀₉O₂, CuO-CeO₂-based adsorbents such as Cu_{0 J}Ce₀₉O₂, FeO-CeO₂-based adsorbents such as Fe_{0 1}Ce₀₉O₂, GeO_x-CeO₂ -based adsorbents where 1 ≤Ξ x^ 2 such as Ge_{0 1}Ce₀₉O₂, HfO_x- CeO₂-based adsorbents where 1 ^ x=≤ 2 such as Hf_{0 1}Ce₀₉O₂, IrO₂-CeO₂ -based adsorbents such as Ir_{0 1}Ce₀₉O₂, La₂O₃-CeO₂-based adsorbents such as La_{0 1}Ce₀₉O₂, MgO_x-CeO₂-based adsorbents where 1=≤ x^ 2 such as Mg_{0 1}Ce₀₉O₂, MoO_x-CeO₂ -based adsorbents where 1 ≤ x=≤ 3 such as Mo_{0 1}Ce₀₉O₂, NiO-CeO₂-based adsorbents such as Ni_{0 1}Ce₀₉O₂, OsO₂-CeO₂-based adsorbents such as Os_{0 1}Ce₀₉O₂, PbO-CeO₂ -based adsorbents such as Pb_{0 1}Ce₀₉O₂, PdO_x-CeO₂-based adsorbents where 0 < x ≤Ξ 1 such as

as Sc_{0 1}Ce₀₉O₂, SnO_x-CeO₂-based adsorbents where 0 <x≤Ξ 2 such as

adsorbents such as Ti_xCe_yO₂ where 0<x/y <_. 1 and where 0<x<l and 0<y<l such as Ti_{0 1}Ce₀₉O₂, Ti_{0 5}CeO ₅O₂, and Ti₀₉Ce₀ iθ₂, WO₃-CeO₂-based adsorbents such as W_{0 1}Ce₀₉O₂, Y₂O₃-CeO₂-based adsorbents such as Yf_nCe₀₉O₂, and ZrO_x- CeO₂-based adsorbents where 0<x^2 such as Zr_{0 1}Ce₀₉O₂.

The novel adsorbents have high adsorptive selectivity and capacity for sulfur compounds in the presence of aromatics.

In a second aspect, the invention relates to the use of these novel adsorbents in, such as, devices such as fixed-bed type absorbers, fluidized-bed type absorbers, moving-bed type absorbers, and rotating type absorbers to

\ remove sulfur and sulfur compounds such as thiols, disulfides, sulfides and thiophenic compounds from hydrocarbon streams such as hydrocarbon fuels, lubricant oils and hydrocarbon solvents and mixtures thereof, preferably hydrocarbon fuels such as gasoline, jet fuel, diesel fuel, naphtha, kerosene, gas oil and vacuum gas oil and mixtures thereof.

In this second aspect, a hydrocarbon stream contacts any one or more of the adsorbents over a temperature range of about O ⁰C to about 100 ⁰C, preferably about 5⁰C to about 70 ⁰C, more preferably at about 25 ⁰C, and at a pressure of about 0.05 MPa to about 0.20 MPa, preferably at about 0.10 MPa to about 0.15 MPa, more preferably at about atmospheric pressure, for a time sufficient to enable the adsorbent to adsorb sulfur and sulfur compounds such as thiols, disulfides, sulfides and thiophenic compounds and mixtures thereof, which may present in the hydrocarbon streams.

Use of these adsorbents to remove any one or more of sulfur and sulfur compounds from the hydrocarbon streams advantageously may be performed without hydrogen to produce clean liquid and gaseous hydrocarbon streams having less than about 1 ppmw sulfur to about 50 ppmw sulfur, typically about 10 ppmw sulfur or less, and clean hydrocarbon fuels having less than about 1 ppmw sulfur to about 50 ppmw sulfur, typically about 1 ppmw sulfur or less. The clean liquid and gaseous hydrocarbon streams may be used for fuel processing as well as directly in fuel cells.

The invention is further described in detail below by reference to the following detailed description and non-limiting examples.

DETAILED DESCRIPTION OF THE INVENTION Method of Manufacture of Adsorbents

Generally, the novel adsorbents are made by mixing an aqueous solution of a cerium oxide precursor that has a concentration range of about 0.02 M to about 1.0 M, preferably about 0.05 M to about 0.5 M, more preferably about 0.10 M to about 0.20 M with an aqueous metal salt solution that has a concentration range of about 0.002 M to about 0.10 M, preferably about 0.005 M to about 0.05 M, more preferably about 0.01 M to about 0.02 M to form a first solution. Useful aqueous solutions of cerium oxide precursors include but are not limited to any one or more of ammonium cerium nitrate, cerium nitrate hexahydrate, cerium acetylacetonate hydrate, cerium sulfate hydrate, and mixtures thereof. Useful aqueous metal salt solutions include but are not limited to aqueous solutions of a metal oxide precursor such metal chlorite hydrates such as osmium chlorite hydrate, metal nitrate hydrates such as lanthanum nitrate hydrate, ferrous nitrate hydrate, cobalt nitrate hydrate, nickel nitrate hydrate, gold chloride hydrate and mixtures thereof, metal chlorides such as ruthenium chloride, iridium chloride, rhodium chloride, hafnium chloride, tin chloride, germanium chloride, platinum chloride, palladium chloride and mixtures thereof, metal nitrates such as lead nitrate, strontium nitrate, silver nitrate, barium nitrate, beryllium nitrate, calcium nitrate and mixtures thereof, chromium nitrate nonahydrate, ammonium molybdate tetrahydrate, magnesium nitrate hexahydrate, zirconyl nitrate titanium oxysulfate-sulfuric acid complex hydrate and mixtures of any one or more of the above.

The first solution is mixed with an aqueous urea solution that has a concentration range of about 10 M to about 0.1 M, preferably about 2.0 M to about 0.2 M, more preferably about 1.0 M to about 0.5 M to produce a mixed solution. The mixed solution is heated to form precipitates, and then cooled to room temperature to produce a cooled slurry solution. The cooled slurry solution is filtrated to generate precipitates which are heated to form dried precipitates. The dried precipitates then are calcined, such as at about 400 ⁰C to about 600 ° C in an oxidizing atmosphere such as air and to produce the adsorbent.

The adsorbents may include one or more oxidation catalysts such as Pt, Pd, V₂O₅, CuO, CrO_x, Ag₂O, MoO₃, WO₃, MnO, Nb₂O₅, CoO, Fe₂O₅, ZnO and NiO to accelerate oxidation of the adsorbed sulfur and sulfur compounds and to enable use of lower oxidation temperatures. The catalysts may be present in an amount of about 0.2 wt.% to about 25 wt.%, preferably about 0.5 wt.% to about 2.0 wt.%, based on the weight of the adsorbent. The oxidation catalysts may be incorporated into the adsorbent by loading the catalyst onto adsorbent by, such as, the incipient wetness impregnation method.

Method of use of Adsorbents

In use, an influent liquid or gaseous hydrocarbon stream to be desulfurized is passed through a bed of adsorbent, such as a fixed bed of the adsorbent to produce a desulfurized hydrocarbon stream. A liquid hydrocarbon stream typically is passed at a temperature of about 0 ⁰C to about 100 ⁰C, preferably about 5°C to about 70°C, more preferably about 2O⁰C to about 30°C, even more preferably at about 25 ⁰C, and at a pressure of about 0.05 MPa to about 0.20 MPa, preferably about 0.10 MPa to about 0.15 MPa, more preferably at about atmospheric pressure. A gaseous influent hydrocarbon stream is passed at a temperature of about 0 ⁰C to about 100 ⁰C and at a pressure of about 0.1 MPa to about 5.0 MPa, preferably about 0.1 MPa to about 10 MPa. Typically, the adsorbent is at a temperature of about 0⁰C to about 100° C.

Adsorbent saturated with sulfur and sulfurized compounds may be regenerated and then reused.

Regeneration Regeneration of the saturated adsorbent may be performed by passing an oxidizing agent, such an oxidizing gas or an oxidizing liquid, over the adsorbent. Oxidizing gases which may be used include air, ozone, N₂O, O₂- containing gas, N₂O-containing gas or ozone-containing gas, or mixtures thereof. Oxidizing liquids which may be employed include H₂O₂, nitric acid, alkyl hydroperoxides such as tert-butyl hydroperoxide and cumene hydroperoxide , or mixtures thereof.

Oxidizing gases used for regeneration have an oxidizing gas partial pressure of about 5 v % to about 100 v %, preferably about 10 v % to about 90 v %, more preferably about 20v % to about 8Ov %. When an oxidizing gas or gases is passed through the adsorbent, the oxidizing gases are heated to about 100⁰C to about 700 °C, preferably about 200⁰C to about 600°C, more preferably about 350⁰C to about 600°C. The oxidizing gases are passed over the adsorbent for a time sufficient to achieve the regeneration, i.e., to remove about 90 % or more of adsorbed sulfur and sulfur compounds from the adsorbent. This time is typically about 10 min to about 120 min. During regeneration, the adsorbed sulfur and sulfur compounds react with O₂, or ozone or N₂O to form SO_x and CO₂ which leave the adsorbent. When oxidizing liquids are used, they typically are at a temperature of about 50 ⁰C to about 300 ⁰C, preferably about 80⁰C to about 250⁰C, more preferably about 80 ⁰C to about 200 ⁰C. After oxidation by using oxidizing liquids, the adsorbent is dried under a flow of air, N₂ or oxygen- containing gas at about 100° C to about 700 ⁰C, preferably about 200° C to about 600°C, more preferably about 350°C to about 500°C. After regeneration, the adsorbent is cooled to room temperature for use in a next cycle of adsorptive desulfurization of hydrocarbon streams.

The invention is further described below by reference to the following non-limiting examples.

Example 1: Manufacture Of La₀₁Ce₀₉O₂ Adsorbent

Urea in an amount of 35 g is placed in a glass beaker, and 800 ml deionized water is added to make 800 ml of 0.728 M aqueous urea solution. 8.22 g of 99.99 % pure ammonium cerium nitrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.149 M ammonium cerium nitrate solution.

0.8403 g of 99.99 % pure lanthanum nitrate hydrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.0259 M lanthanum nitrate solution.

100 mL of the lanthanum nitrate hydrate complex solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

All of the first solution is mixed with 800 ml of the aqueous solution and vigorously mixed by magnetic stirrer to produce a mixed solution. The mixed solution is heated at 2 °C/min to 90⁰C, maintained at 90⁰C for 8 hours to produce precipitates, and then cooled at 10 °C/min to room temperature to produce a cooled slurry solution.

The cooled slurry solution is filtrated to separate the precipitates. The precipitates then are dried at 100 ⁰C under air flow to produce dried precipitates. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to produce La_{0 1}Ce₀₉O₂ adsorbent. Example 2: Manufacture Of Y₀₁Ce₀₉O₂ Adsorbent

Urea in an amount of 35 g is placed in a glass beaker, and 800 ml deionized water is added to make 800 ml of 0.728 M aqueous urea solution.

8.22 g of 99.99 % pure ammonium cerium nitrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.149 M ammonium cerium nitrate solution.

0.5795 g of 99.9 % pure yttrium nitrate hydrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.013 M yttrium nitrate solution. 100 mL of the yttrium nitrate hydrate solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

All of the first solution is mixed with 800 ml of the aqueous solution and vigorously mixed by magnetic stirrer to produce a mixed solution.

The mixed solution is heated at 2 °C/min to 9O⁰C, maintained at 90⁰C for 8 hours to produce precipitates, and then cooled at 10 °C/min to room temperature to produce a cooled slurry solution. The cooled slurry solution is filtrated to separate the precipitates.

The precipitates then are dried at 100 ⁰C under air flow to produce dried precipitates. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Y₀ ,Ce₀₉O₂

Example 2A: Manufacture of Sc₀₁Ce₀₉O₂ Adsorbent

0.388 g of 99% pure scandium nitrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.017 M scandium nitrate solution. 100 mL of the scandium nitrate solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution. All of the first solution is mixed with 800 ml of the aqueous solution and vigorously mixed by magnetic stirrer to produce a mixed solution. The mixed solution is heated at 2 °C/min to 9O⁰C, maintained at 9O⁰C for 8 hours to produce precipitates, and then, cooled at 10 °C/min to room temperature to produce a cooled slurry solution.

The cooled slurry solution is filtrated to separate the precipitates. The precipitates are dried at 100 ⁰C under air flow. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Sc_{0 J}Ce₀₉O₂ adsorbent.

Example 3: Manufacture Of Cu₀₁Ce₀₉O₂ Adsorbent

0.4142 g of 98 % pure copper nitrate hydrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.016 M copper nitrate -solution. 100 mL of the copper nitrate hydrate solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

All of the first solution is mixed with 800 ml of the aqueous solution and vigorously mixed by magnetic stirrer to produce a mixed solution. The mixed solution is heated at 2 °C/min to 90⁰C, maintained at 9O⁰C for 8 hours to produce precipitates, and then, cooled at 10 °C/min to room temperature to produce a cooled slurry solution.

The cooled slurry solution is filtrated to separate the precipitates. The precipitates are dried at 100 ⁰C under air flow. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Cu_{0 1}Ce₀₉O₂ adsorbent. Example 3A: Manufacture OfAu₀₁Ce₀₉O₂ Adsorbent

0.5663 g of 99.999 % pure gold chloride hydrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.015 M gold chloride solution. 100 mL of the gold chloride solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

All of the first solution is mixed with 800 ml of the aqueous solution and vigorously mixed by magnetic stirrer to produce a mixed solution. The mixed solution is heated at 2 °C/min to 9O⁰C, maintained at 90⁰C for 8 hours to produce precipitates, and then, cooled at 10 °C/min to room temperature to produce a cooled slurry solution.

The cooled slurry solution is filtrated to separate the precipitates. The precipitates then are dried at 100 ⁰C under air flow. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Au_{0 1}Ce₀₉O₂ adsorbent.

Example 4: Manufacture Of Ni₀₁Ce₀₉O₂ Adsorbent

0.3826 g of 99.999 % pure nickel nitrate hydrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.013 M nickel nitrate solution. 100 mL of the nickel nitrate solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

All of the first solution is mixed with 800 ml of the aqueous solution and vigorously mixed by magnetic stirrer to produce a mixed solution. The mixed solution is heated at 2 °C/min to 9O⁰C, maintained at 9O⁰C for 8 hours to produce precipitates, and then, cooled at 10 °C/min to room temperature to produce a cooled slurry solution.

The cooled slurry solution is filtrated to separate the precipitates. The precipitates then are dried at 100 ⁰C under air flow. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Ni_{0 J}Ce₀₉O₂ adsorbent.

Example 4A: Manufacture of Pd₀ ,Ce₀₉O₂ Adsorbent Urea in an amount of 35 g is placed in a glass beaker, and 800 ml deionized water is added to make 800 ml of 0.728 M aqueous urea solution.

8.22 g of 99.99 % pure ammonium cerium nitrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.149 M ammonium cerium nitrate solution. 0.2956 g of 99 % pure palladium chloride from Aldrich is dissolved in

100 ml deionized to make 100 mL of 0.015 M palladium chloride solution.

100 mL of the palladium chloride solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

All of the first solution is mixed with 800 ml of the aqueous solution and vigorously mixed by magnetic stirrer to produce a mixed solution. The mixed solution is heated at 2 °C/min to 9O⁰C, maintained at 9O⁰C for 8 hours to produce precipitates, and then cooled at 10 °C/min to room temperature to produce a cooled slurry solution.

The cooled slurry solution is filtrated to separate the precipitates. The precipitates are dried at 100 ⁰C under air flow. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 °C for 6 hours to yield Pd_{0 1}Ce₀₉O₂ adsorbent.

Example 4B: Manufacture Of Pt₀₁Ce₀₉O₂ Urea in an amount of 35 g is placed in a glass beaker, and 800 ml deionized water is added to make 800 ml of 0.728 M aqueous urea solution.

8.22 g of 99.99 % pure ammonium cerium nitrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.149 M ammonium cerium nitrate solution. 0.5614 g of 99 % pure platinum chloride from Aldrich is dissolved in

100 ml deionized water to make 100 mL of 0.015 M platinum chloride solution.

100 mL of the platinum chloride solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

The cooled slurry solution is filtrated to separate the precipitates. The precipitates are dried at 100 ⁰C under air flow. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Pt_{0 1}Ce₀₉O₂ adsorbent.

Example 5: Manufacture Of Ca₀₁Ce₀₉O₂ Adsorbent

8.22 g of 99.99 % pure ammonium cerium nitrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.149 M ammonium cerium nitrate solution. 0.2612 g of 99 % pure calcium nitrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.014 M calcium nitrate solution.

100 mL of the calcium nitrate solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution. All of the first solution is mixed with 800 ml of the aqueous solution and vigorously mixed by magnetic stirrer to produce a mixed solution. The mixed solution is heated at 2 °C/min to 90⁰C, maintained at 9O⁰C for 8 hours to produce precipitates, and then, cooled at 10 °C/min to room temperature to produce a cooled slurry solution. The cooled slurry solution is filtrated to separate the precipitates. The precipitates are dried at 100 ⁰C under air flow. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Ca₀ ,Ce₀₉O₂ adsorbent.

Example 5A: Manufacture of Be₀₁Ce₀₉O₂ Adsorbent

0.2993 g of 99 % pure beryllium nitrate solution from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.020 M beryllium nitrate solution. 100 mL of the beryllium nitrate solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

All of the first solution is mixed with 800 ml of the aqueous solution and vigorously mixed by magnetic stirrer to produce a mixed solution. The mixed solution is heated at 2 °C/min to 90⁰C, maintained at 9O⁰C for 8 hours to produce precipitates, and then, cooled at 10 °C/min to room temperature to produce a cooled slurry solution. The cooled slurry solution is filtrated to separate the precipitates. The precipitates are dried at 100 ⁰C under air flow. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Be₀ ,Ce₀₉O₂ adsorbent.

Example 5B: Manufacture of Mg₀ ,Ce₀₀O₂ Adsorbent

0.4274 g of 99 % pure magnesium nitrate hexahydrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.015 M magnesium nitrate solution.

100 mL of the magnesium nitrate solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

All of the first solution is mixed with 800 ml of the aqueous solution and vigorously mixed by magnetic stirrer to produce a mixed solution. The mixed solution is heated at 2 °C/min to 90⁰C, maintained at 90⁰C for 8 hours to produce precipitates, and then, cooled at 10 °C/min to room temperature to produce a cooled slurry solution.

The cooled slurry solution is filtrated to separate the precipitates. The precipitates are dried at 100 ⁰C under air flow. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Mg_{0 1}Ce₀₉O₂ adsorbent.

Example 5C: Manufacture of Ba₀ ,Ce_{0 g}O₂ adsorbent Urea in an amount of 35 g is placed in a glass beaker, and 800 ml deionized water is added to make 800 ml of 0.728 M aqueous urea solution. 8.22 g of 99.99 % pure ammonium cerium nitrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.149 M ammonium cerium nitrate solution.

0.4356 g of 90 % pure barium nitrate hydrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.015 M barium nitrate solution.

100 mL of the barium nitrate solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

The cooled slurry solution is filtrated to separate the precipitates. The precipitates are dried at 100 ⁰C under air flow. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Ba₀.,Ce₀₉O₂ Adsorbent.

Example 6: Manufacture OfAg₀₁Ce₀₀O₂ adsorbent Urea in an amount of 35 g is placed in a glass beaker, and 800 ml deionized water is added to make 800 ml of 0.728 M aqueous urea solution.

8.22 g of 99.99 % pure ammonium cerium nitrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.149 M ammonium cerium nitrate solution. 0.7031 g of 99 % pure silver nitrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.037 M silver nitrate solution.

100 mL of the silver nitrate solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

The cooled slurry solution is filtrated to separate the precipitates. The precipitates then are dried at 100 ⁰C under air flow. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Ag_{0 !}Ce₀₉O₂ adsorbent.

Example 7: Manufacture Of Sr₀₁Ce₀₉O₂ Adsorbent Urea in an amount of 35 g is placed in a glass beaker, and 800 ml deionized water is added to make 800 ml of 0.728 M aqueous urea solution.

8.22 g of 99.99 % pure ammonium cerium nitrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.149 M ammonium cerium nitrate solution. 0.5711 g of 99 % pure strontium nitrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.024 M strontium nitrate solution.

100 mL of the strontium nitrate solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

The cooled slurry solution is filtrated to separate the precipitates. The precipitates then are dried at 100 ⁰C under air flow. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Sr₀ ,Ce₀₉O₂ adsorbent. Example 8: Manufacture of Pb₀₁Ce₀₉O₂ Adsorbent

8.22 g of 99.99% pure ammonium cerium nitrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.149 M ammonium cerium nitrate solution.

1.3506 g of 99 % pure lead nitrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.036 M lead nitrate solution.

100 mL of the lead nitrate solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

The cooled slurry solution is filtrated to separate the precipitates. The precipitates then are dried at 100 ⁰C under air flow. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Pb_{0 1}Ce₀₉O₂ adsorbent.

Example 8A: Manufacture of Ge₀₁Ce₀₉O₂ Adsorbent

0.3574 g of germanium chloride from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.015 M germanium chloride solution.

100 mL of the germanium chloride solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution. All of the first solution is mixed with 800 ml of the aqueous solution and vigorously mixed by magnetic stirrer to produce a mixed solution. The mixed solution is heated at 2 °C/min to 90⁰C, maintained at 9O⁰C for 8 hours to produce precipitates, and then, cooled at 10 °C/min to room temperature to produce a cooled slurry solution.

The cooled slurry solution is filtrated to separate the precipitates. The precipitates are dried at 100 ⁰C under air flow. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Pd_{0 1}Ce₀₉O₂ adsorbent.

Example 8B: Manufacture Of Sn_{0 1}Ce₀₉O₂ Adsorbent

0.4342 g of 98 % pure tin chloride from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.015 M tin chloride solution. 100 mL of the tin chloride solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

The cooled slurry solution is filtrated to separate the precipitates. The precipitates are dried at 100 ⁰C under air flow. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Sn₀ ,Ce₀₉O₂ adsorbent. Particularly preferred adsorbents are TiO₂-CeO₂ bas^d adsorbents of the formula Ti_xCe_yO₂, where 0<x/y <_. 1 and where 0<x<.l and t)<y<l.

Example 9: Manufacture Of Ti_{0 1}Ce₀₉O₂ Adsorbent Urea in an amount of 35 g is placed in a glass beaker,- and 800 ml deionized water is added to make 800 ml of 0.728 M aqueous urea solution. 8.22 g of 99.99 % pure, ammonium cerium nitrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.149 M ammonium cerium nitrate solution. 0.3120 g of synthesis grade titanium oxysulfate-sulfuric acid complex hydrate from Aldrich is dissolved in 100 ml deionized wa\er over a period of 1.5 hours to make 100 mL of titanium oxysulfate-sulfuric acid solution. 100 mL of the titanium oxysulfate-sulfuric acid complex hydrate solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

All of the first solution is mixed with 800 ml of the aqueous solution and vigorously mixed by magnetic stirrer to produce a mixed solution. The mixed solution is heated at 2 °C/min to 9O⁰C, maintained at 90°Cifor 8 hours to produce precipitates, and then, cooled at 10 °C/min to room temperature to produce a cooled slurry solution.

The cooled slurry solution is filtrated to separate trie precipitates. The precipitates then are dried at 100 ⁰C under air flow to produce dried precipitates. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Ti_{0 1}Ce₀₉O₂ adsorbent.

Example 9A: Manufacture of Zr₀₁Ce₀₉O₂ Adsorbent

Urea in an amount of 35 g is placed in a glass beaker, and 800 ml deionized water is added to make 800 ml of 0.728 M aqueous urea solution. 8.22 g of 99.99 % pure ammonium cerium nitrate from Aldrich is dissolve in 100 ml deionized water to make 100 mL of 0.149 M ammonium cerium nitrate solution.

0.3854 g of 99 % pure zirconyl nitrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.015 M zirconyl nitrate solution.

100 mL of the zirconyl nitrate solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

The cooled slurry solution is filtrated to separate the precipitates. The precipitates are dried at 100 ⁰C under air flow. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Zr_{0 1}Ce₀₉O₂ adsorbent.

Example 9B: Manufacture Of Hf₀₁Ce₀₉O₂ Adsorbent Urea in an amount of 35 g is placed in a glass beaker, and 800 ml deionized water is added to make 800 ml of 0.728 M aqueous urea solution.

8.22 g of 99.99 % pure ammonium cerium nitrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.149 M ammonium cerium nitrate solution. 0.5338 g of 98 % pure hafnium chloride from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.015 M hafnium chloride solution.

100 mL of the hafnium chloride solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

The cooled slurry solution is filtrated to separate the precipitates. The precipitates are dried at 100 ⁰C under air flow. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Hf_{0 1}Ce₀₉O₂ adsorbent.

Example 10: Manufacture of Co₀₁Ce₀₉O₂ Adsorbent Urea in an amount of 35 g is placed in a glass beaker, and 800 ml deionized water is added to make 800 ml of 0.728 M aqueous urea solution.

8.22 g of 99.99% pure ammonium cerium nitrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.149 M ammonium cerium nitrate solution. 0.3842 g of 99% pure cobalt nitrate hydrate from Aldrich is dissolved in

100 ml deionized water to make 100 mL of 0.013 M cobalt nitrate solution.

100 mL of the cobalt nitrate solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

The cooled slurry solution is filtrated to separate the precipitates. The precipitates then are dried at 100 ⁰C under air flow to produce dried precipitates. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Co₀ ,Ce₀₉O₂ adsorbent. Example 1OA: Manufacture of Rh₀₁Ce₀₉O₂ Adsorbent

0.3488 g of 98 % pure rhodium chloride from Aldrich is dissolved in 100 ml deionized to make 100 mL of 0.015 M rhodium chloride solution.

100 mL of the rhodium chloride solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

The cooled slurry solution is filtrated to separate the precipitates. The precipitates are dried at 100 ⁰C under air flow. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Rh₀ ,Ce₀₉O₂ adsorbent.

Example 1OB: Manufacture Of Ir₀₁Ce₀₉O₂ Adsorbent

0.4976 g of 99.9 % pure iridium chloride from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.015 M iridium chloride solution. 100 mL of the iridium chloride solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution. All of the first solution is mixed with 800 ml of the aqueous solution and vigorously mixed by magnetic stirrer to produce a mixed solution. The mixed solution is heated at 2 °C/min to 9O⁰C, maintained at 9O⁰C for 8 hours to produce precipitates, and then, cooled at 10 °C/min to room temperature to produce a cooled slurry solution.

The cooled slurry solution is filtrated to separate the precipitates. The precipitates are dried at 100 ⁰C under air flow. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Ir_{0 1}Ce₀₉O₂ adsorbent.

Example 11: Manufacture Of Fe₀₁Ce₀₉O₂ Adsorbent

Urea in an amount of 35 g is placed in a glass beaker, and 800 ml deionized water is added to make 800 ml of 0.728 M aqueous urea solution. 8.22 g of 99.99% pure ammonium cerium nitrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.149 M ammonium cerium nitrate solution.

0.3640 g of 99% pure iron nitrate hydrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.015M ferrous nitrate solution. 100 mL of the iron nitrate solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

The cooled slurry solution is filtrated to separate the precipitates. The precipitates then are dried at 100 ⁰C under air flow to produce dried precipitates. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Fe_{0 J}Ce₀₉O₂ adsorbent. Example HA: Manufacture Of Ru₀₁Ce₀₉O₂ Adsorbent

0.3457 g of 99.98% pure ruthenium chloride from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.015 M ruthenium chloride solution. 100 mL of the ruthenium chloride solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

The cooled slurry solution is filtrated to separate the precipitates. The precipitates are dried at 100 ⁰C under air flow. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield R4₀ ^Ce₀₉O₂ adsorbent.

Example HB: Manufacture Of Os₀₁Ce₀₉O₂ Adsorbent

0.4493 g of 95 % osmium chloride hydrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.015 M osmium chloride solution. 100 πiL of the osmium chlorite hydrate solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

AU of the first solution is mixed with 800 ml of the aqueous solution and vigorously mixed by magnetic stirrer to produce a mixed solution. The mixed solution is heated at 2 °C/min to 9O⁰C, maintained at 9O⁰C for 8 hours to produce precipitates, and then, cooled at 10 °C/min to room temperature to produce a cooled slurry solution.

The cooled slurry solution is filtrated to separate the precipitates. The precipitates are dried at 100 ⁰C under air flow. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Os_{0 1}Ce₀₉O₂ adsorbent.

Example 12: Manufacture Of W₀₁Ce₀₉O₂ Adsorbent Urea in an amount of 35 g is placed in a glass beaker, and 800 ml deionized water is added to make 800 ml of 0.728 M aqueous urea solution. 8.22 g of 99.99% pure ammonium cerium nitrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.149 M ammonium cerium nitrate solution. 0.1406 g of 99.99 % pure ammonium metatungstate hydrate from

Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.015 M

W-containing solution.

100 mL of the W-containing solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution. All of the first solution is mixed with 800 ml of the aqueous solution and vigorously mixed by magnetic stirrer to produce a mixed solution. The mixed solution is heated at 2 °C/min to 9O⁰C, maintained at 90⁰C for 8 hours to produce precipitates, and then, cooled at 10 °C/min to room temperature to produce a cooled slurry solution. The cooled slurry solution is filtrated to separate the precipitates. The precipitates then are dried at 100 ⁰C under air flow to produce dried precipitates. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield W_{0 1}Ce₀₉O₂ adsorbent.

Example 12A: Manufacture of Mo_{0 α}Ce₀₉O₂ Adsorbent

0.2943 g of 99.98% pure ammonium molybdate tetrahydrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.015 M ammonium molybdate tetrahydrate solution.

100 mL of the ammonium molybdate tetrahydrate solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

The cooled slurry solution is filtrated to separate the precipitates. The precipitates are dried at 100 ⁰C under air flow. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Mo_{0 J}Ce₀₉O₂ adsorbent.

Example 12B: Manufacture Of Cr₀₁Ce₀₉O₂ Adsorbent

Urea in an amount of 35 g is placed in a glass beaker, and 800 ml deionized water is added to make 800 ml of 0.728 M aqueous urea solution. 8.22 g of 99.99 % pure ammonium cerium nitrate from Aldrich is dissolved in 100 ml deionized water to make 100 mL of 0.149 M ammonium cerium nitrate.

0.670 g of 99% pure chromium nitrate nonahydrate from Aldrich is dissolved in 100 ml deionized to make 100 mL of 0.015M chromium nitrate solution.

100 mL of the nitrate nonahydrate solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

The cooled slurry solution is filtrated to separate the precipitates. The precipitates are dried at 100 ⁰C under air flow. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Cr_0.JCe₀₉O₂ adsorbent

Adsorption Performance

During adsorption tests of the adsorbents of Examples 1-12, model fuel (I) having the composition shown in Table A is passed at a flow rate of 0.05 mL/min over 1 g of adsorbent in a bed having the dimensions of 4.6 mm (ID) x 37.5 mm (length) at room temperature (25 °C)and 4.8 ¹ LHSV (liquid hour space velocity).

The sulfur breakthrough capacity (mg-S/Ads-g) at sulfur levels of 1 ppmw and 30 ppmw, respectively, are measured by analyzing sulfur concentration at the outlet of the bed using gas chromatography-with a flame ionization detector ("GC-FID"). The adsorptive breakthrough capacities of the adsorbents at sulfur levels of 1 ppmw and 30 ppmw, respectively, are shown in Table 1. Table A: Model fuel (I) composition

Compound S cone. MoI cone. (%)

(ppmw)

Sulfur

Thiophene (T) 110 0.034

Tetrahydrothiophene (THT) 95 0.030

2-methyl benzothiophene (2MBT) 115 0.036

Benzothiophene (BT) 100 0.031

Aromatics

Toluene 0.033

Olefin

1-C₈ 0.033

Internal standard (IS) n-C₉ 0.033

Solvent n-C₇ 99.770

Table 1

3 _*-^JU_o.iV-«eo,gU₂ 0.19 0.33

4 Ni_0-1Ce_0-9O₂ 0.00 0.38

5 *-^J^O.l*-'6o.9*-'2 0.00 0.07

6 Ag_0-1Ce_0-9O₂ 0.20 0.36

8 "t)_0-1v_ιe₀.gU₂ 0.00 0.00

9 0.55 0.86

10 ""o.i^o.s^-'z 0.22 0.48

11 -^ e_0-1CJeO_-9O₂ 0.00 0.28

12 W_0-1Ce_0-9O₂ 0.98 0.98

The adsorption capacities of the fresh and regenerated Ti_{0 1}Ce₀₉O₂ adsorbents of Example 9 also are measured in a fixed-bed flow system. Adsorption by the fixed- bed flow system entails first pretreating a fixed bed of the adsorbent by passing air/O₂ which contains oxygen in an amount of 21 vol. % at a flow rate of 100 ml/min through the adsorbent while increasing the temperature of the adsorbent to 350° C for 2 hours to activate the adsorbent. The adsorbent then is cooled to room temperature under air/O₂ flow at 100 ml/min with heat turned off.

The adsorption is conducted at LHSV: 4.8 h^"1 and room temperature using model fuel (I) feedstock. The spent adsorbents are regenerated by the procedure: 1) passing air at a flow rate of 100 ml/min through the adsorbent bed for 10 min; 2) increasing the temperature of the adsorbent bed to 375 ⁰C at a rate of 15 °C/min under 100 ml/min air flow; 3) holding at 375 ⁰C for 120 min, and 4) cooling the temperature to room temperature under the air flow. Adsorption then again is conducted at LHSV: 4.8 h ¹ and room temperature using model fuel (I). The adsorption capacity results for the fresh and regenerated adsorbents at sulfur levels of 1 ppmw and 30 ppmw, respectively, are shown in Table 2.

Table 2

Cycles Sample Capacity: mg-S/ Capacity: mg-S/

Ads.-g Ads-g (< lppmw) (< 30ppmw)

1 Fresh Adsorbent 2.3 3.3

2 Regenerated 2.5 2.9

Adsorbent

Example 13: Ti₀ ,Ce_{0 β}O₂ Adsorbent Doped with 1 wt% of Pd Oxidation Catalyst.

1 wt.% Pd doped Ti_{0 1}Ce₀₉O₂ adsorbent is prepared by loading Pd onto the Ti_{0 1}Ce₀₉O₂ of example 9 by using the incipient wetness impregnation method. In this method, a Pd doping solution is prepared by dissolving 0.213 g of > 99% pure tetrammine palladium (II) nitrate from Aldrich in 12.34 mL of deionized water. All of this solution is mixed with 11.5 gm of the precipitates dried at 450 C for 6 hours as in Example 9 to form Pd impregnated samples. The Pd impregnated samples are dried at 100⁰C overnight to yield Ti_{0 1}Ce₀₉O₂ adsorbent doped with 1 wt% of Pd.

The adsorption capacities of fresh and regenerated 1 wt. % Pd doped Ti_{0 J}Ce₀₉O₂ adsorbent are evaluated in the fixed-bed flow system. Adsorption is conducted at room temperature and 1.2 h^'1 of LHSV. Model fuel (II) having the composition shown in Table B is used for these tests. Regeneration is conducted at 375 ⁰C under an air flow of 100 mL/min for 2 hrs at sulfur levels of 1 ppmw and 30 ppmw, respectively. The results are shown in Table 3.

Table B. Model fuel (II) composition

Compound S cone. MoI cone. (%)

(ppmw)

Sulfur

Thiophene (T) 50 0.021

2-methylthiophene (2MT) 50 0.021

3-methylthiophene (3MT) 50 0.021

2,5-dimethylthiophene (2, 5-DMT) 50 0.021

Benzothiophene (BT) 60 0.025

Solvent

Iso-octane 99.893

Table 3

Cycles Sample Capacity: mg-S/ Ads.-g Capacity: mg-S/ Ads-g

(< lppmw) (< 30ppmw)

1^st Fresh 2.8 2.8

2^nd R Re*gσ. @ fa) 33775R°θCr, 27hh 2.7 2.7

3^rd R Repgo. @ rfr 3-i7v5s⁰oCr., 2 ?hh 2.4 2.9

Example 14: Manufacture of Tio.₅Ceo.₅O₂ Adsorbent

Urea in an amount of 75 g is placed in a glass beaker, and 800 ml deionized water is added to make 800 ml of 1.56 M aqueous urea solution.

32.9 g of 99.99 % pure ammonium cerium nitrate from Aldrich is dissolved in deionized water to make 100 mL of 0.60 M ammonium cerium nitrate solution.

18.0 g of synthesis grade titanium oxysulfate-sulfuric acid complex hydrate from Aldrich is dissolved in deionized water over a period of 1.5 hours to make 100 mL of 0.60 M titanium oxysulfate-sulfuric acid complex hydrate solution. 100 mL of the titanium oxysulfate-sulfuric acid complex hydrate solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution.

All of the first solution is mixed with 800 ml of the aqueous solution and vigorously mixed by magnetic stirrer to produce a mixed solution. The mixed solution is heated at 2 °C/min to 9O⁰C, maintained at 9O⁰C for 8 hours to produce precipitates, and cooled at 10 °C/min to room temperature to produce a cooled slurry solution.

The cooled slurry solution is filtrated to separate precipitates. The precipitates are dried at 100 ⁰C under air flow to produce dried precipitates. The dried precipitates are calcined in air flowing at 100 mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Ti₀₅Ce₀₅O₂ adsorbent.

Example 15: Manufacture of Tio.9Ceo.₁O₂ Adsorbent

Urea in an amount of 75 g is placed in a glass beaker, and 800 ml deionized water is added to make 800 ml of 1.56 M aqueous urea solution. 8.22 g of 99.99 % pure ammonium cerium nitrate from Aldrich is dissolved in deionized water to make 100 mL of 0.149 M ammonium cerium nitrate solution.

32.7 g of synthesis grade Titanium oxysulfate-sulfuric acid complex hydrate from Aldrich is dissolved in deionized water over a period of 1.5 hours to make 100 mL of 1.215 M Ti oxysulfate-sulfuric acid complex hydrate solution. 100 mL of the titanium oxysulfate-sulfuric acid complex hydrate solution is mixed with 100 mL of the ammonium cerium nitrate solution to form a first solution. All of the first solution is mixed with 800 ml of the urea aqueous solution and vigorously mixed by magnetic stirrer to produce a mixed solution. The mixed solution is heated at 2 °C/min to 90 ⁰C, maintained at 90 ⁰C for 8 hours to produce precipitates, and then cooled at 10 °C/min to room temperature to produce a cooled slurry solution. The cooled slurry solution is filtrated to separate precipitates. The precipitates are dried at 100 ⁰C under air flow to produce dried precipitates. The dried precipitates are calcined in air flowing at 100 ⁰C mL/min flow while heating at 1.5 °C/min to 450 ⁰C. The precipitates are maintained at 450 ⁰C for 6 hours to yield Ti₀₉Ce₀ ,0₂ adsorbent. The adsorption capacities of the adsorbents of examples 9, 14 and 15 are evaluated in the fixed-bed flow system. The adsorption is conducted at room temperature and 1.2 h ¹ of LHSV using a light JP-8 fuel, which contains 373 ppmw of sulfur compounds, mainly alkylated benzothiophenes. The adsorptive breakthrough capacities of the adsorbents at sulfur levels of 1 and 30 ppmw, respectively, are shown in Table 4.

Table 4

Example Adsorbent Fuel Capacity: mg-S/ Ads.-g Capacity: mg-S/ Ads.-g (< 1 ppmw) (< 30 ppmw)

9 Ti₀₁Ce₀₉O₂ Light JP-8 0.04 0.23

14 Ti₀₅Ce₀₅O₂ Light JP-8 0.31 0.85

15 Ti₀₉Ce₀₁O₂ Light JP-8 2.01 3.26 For comparison of performance of the novel adsorbents with known metal oxide adsorbents, all of the adsorbents, before evaluation, are dried in an oven at 100 ⁰C overnight. Then, 5 g of model fuel (III) having the composition shown in Table C is poured into a glass vial having 0.5 g of the adsorbent. Adsorption is conducted under stirring for 120 min. at room temperature and ambient pressure. After adsorption, the treated fuel is filtered, and total sulfur concentration in the treated fuel is analyzed by an ANTEK 9000 Total Sulfur Analyzer. This procedure is repeated three times for each adsorbent. The average of the results for each adsorbent is shown in Table 5. Table C. Model fuel (III) composition

Compound S cone. MoI cone. MoI cone.

(ppmw) (mmol/kg) (mmol/L)

Sulfur

Tetrahydrothiophene (THT) 106.7 3.333 2.543

Benzothiophene (BT) 100.8 3.149 2.403

2-methyl benzothiophene (2MBT) 105.6 3.299 2.517

Dibenzothiophene (DBT) 100.4 3.137 2.393

4,6-dimethyl benzothiophene 100.5 3.140 2.396

(4,6DMDBT)

Aromatics

Naphthalene (Na) 3.148 2.402

1-methyl naphthalene (IMNa) 3.211 2.450

Phenanthrene (PNT) 3.138 2.394

Olefin

1-C₈ 3.204 2.445

Internal standard (IS) n-C₁₀ 3.338 2.547

Solvent n-C_]4+ n-C₁₂ - -

Table 5

* Adsorbent of Example 15

Example 16: Manufacture of Ti-Ce-Al-O Adsorbent

Urea in an amount of 60.00 g is transferred to a glass beaker; deionized water in an amount of 500 mL is added to make 500 mL of 1.998 M aqueous urea solution.

32.32 g of synthesis grade titanium oxy sulfate-sulfuric acid complex hydrate from Aldrich is mixed with 100 ml deionized water to form a 1.077M titanium oxysulfate-sulfuric acid complex solution.

6.58 g of 99.9 % pure ammonium cerium nitrate from Aldrich is mixed with 100 ml deionized water to make 100 mL of 0.120 M ammonium cerium nitrate solution. 10.04 g of 98 % pure aluminum nitrate nonahydrate from Aldrich is mixed with 100 ml deionized water to make 100 ml of 0.262 M aluminum nitrate nonahydrate solution.

All the titanium oxysulfate-sulfuric acid complex solution, ammonium cerium nitrate solution and aluminum nitrate nonahydrate solution are₍ mixed with 500 ml of the aqueous urea solution for form a mixed solution. Deionized water is added to the solution to achieve a total volume of 1000 mL of the solution, and stirred vigorously by magnetic stirrer.

The mixed solution then is heated at 2 ⁰C /min to a temperature of 95 ⁰C, maintained at 95 ⁰C for 6 hours to produce precipitates, and then cooled at 1' ⁰C /min down to room temperature to produce a cooled slurry solution. The cooled slurry solution is filtrated to remove the precipitates. The precipitates then are dried at 110 ⁰C in an oven under air flow to produce dried precipitates. After drying, the precipitates are calcined under 100 mL/min of air flow at a heating rate of 1 °C/min to 500 ⁰C, and maintained at 500 ⁰C for 4 hours to produce adsorbent. The composition of the adsorbent is shown in Table 6. The adsorbent has a particle size range of 0.1 micron to 30 micron, a pore size range of 0.001 micron to 0.01 micron, and a porosity of 10 vol. % to 70 vol. %.

Example 17: Manufacture of Ti-Ce-Al-Ag-O Adsorbent

Urea in an amount of 60.00 g is transferred to a glass beaker; deionized water in an amount of 500 mL is added to make a 1.998 M aqueous urea solution.

32.32 g of synthesis grade titanium oxysulfate-sulfuric acid complex hydrate from Aldrich is mixed with 100 ml deionized water to form a l_f077M titanium oxysulfate-sulfuric acid complex hydrate solution.

6.58 g of 99.9 % pure ammonium cerium nitrate from Aldrich is mi>ced with 100 ml deionized water to make 100 mL of 0.120 M ammonium

nitrate solution. 10.04 g of 98 % pure aluminum nitrate nonahydrate from Aldrich is mixed with 100 ml deionized water to make 100 ml of 0.262M an aluminum nitrate solution.

4.95 g of 99% pure silver nitrate from Aldrich is mixed with 100 ml deionized water to make 100 mL of 0.288M silver nitrate solution.

All the titanium oxysulfate-sulfuric acid complex solution, ammonium cerium nitrate solution, aluminum nitrate solution and silver nitrate solutions are mixed with 500 ml of the urea solution to make a reaction solution. Deionized water is added to the reaction solution to achieve a total volume of 1000 mL of reaction solution, and stirred vigorously by magnetic stirrer.

The reaction solution then is heated at 2 ⁰C /min to a temperature of 95 ⁰C, maintained at 95 ⁰C for 6 hours to produce precipitates, and then codled at 1 ⁰C /min to room temperature to produce a cooled slurry solution.

The cooled slurry solution then is subjected to filtration to remove trie precipitates. The precipitates then are dried at 110 ⁰C in an oven under air flow to produce dried precipitates. The dried precipitates are calcined under 100 mL/min of air flow at a heating rate of 1 °C/min to 500 ⁰C, and maintained at 500 ⁰C for 4 hours to produce adsorbent. The composition of the calcined precipitates is shown in Table 6. The adsorbent has a particle size range of 0.1 micron to 30 micron, a pore size 0.001 micron to 0.1 micron, and a porosity of 10 vol. % to 70 vol. %.

Table 6

Metal oxide weight percentage (wt%)

Ag₂O Al₂O₃ TiO₂ CeO₂

Example 15 80.7 19.3 Example 16 11.1 71.7 17.2 Example 17 21.7 8.7 56.1 13.5 The sulfur adsorption capacities of the fresh adsorbents and regeneratefl adsorbents of examples 15-17 are evaluated by the batch system. Adsorption by the batch system entails first heating the adsorbent from room temperature to 300 ⁰C at 1.5 °C/min in an oven, maintaining the adsorbent at 300 ⁰C for 2 hours, and cooling to room temperature at 10 °C/min to produce a pretreated adsorbent.

Model fuel (IV) having the composition shown in Table D is added to the pretreated adsorbent and placed into a batch adsorption reactor. The adsorbent is stirred in the fuel for 2 hours at room temperature and ambient atmosphere.\ The resulting treated fuel and adsorbent are separated from each other by centrifuge.

The treated fuel is analyzed by an HP 5890 gas chromatograph with a flame ionization detector (FID) and an Antek 9000S total sulfur analyzer.\The spent adsorbent is regenerated in an oven in the air flowing at the rate of 8^ mL/min while heating the adsorbent from room temperature to 500 ⁰C at 2 °C/min and then maintaining the adsorbent at 500 ⁰C for 4 hours to produce regenerated adsorbent. The adsorbent then is cooled to room temperature under the air flow. The adsorptive capacities of the fresh and regenerated adsorbents are shown in Table 7. The spent adsorbents are regenerated by increasing the adsorbent-bed temperature to 500 ⁰C at 5°C/min and maintaining at 500 "C for 2 hours under an airflow rate of 20 ml/min. The adsorptive capacities of ύ\e regenerated adsorbents treated according to this procedure are also showij in Table 7 with the symbol*.

Table D. Model fuel (IV) composition

Purity Concentration Molar

(g/g) concentration

Wt. % ppmw (mmol/kg)

S

Sulfur compounds

Tetrahydrothiophene 0.99 0.03 105 3.3

Benzothiophene 0.99 0.04 100 3.1

2-MBT 0.97 0.05 100 3.1

DBT 0.98 0.06 100 3.1

4,6-DMDBT 0.97 0.07 100 3.1

Total 505

Aromatics

Naphthalene 0.99 0.04 3.1

1 -Methylnaphthalene 0.97 0.04 3.1

Phenanthrene 0.98 0.06 3.1

Olefin

1-Octene 0.98 0.04 3.1

Alkanes n-Dodecane 0.99 0.05 3.1 n-Decane 0.99 49.76 n-Hexadecane 0.99 49.76

Total 100.00

The adsorbents are regenerated from room temperature to 500 "C at a temperature ramp of 5°C/min and keep final temperature for 2 hours. The air flow rate of 20 ml/min is used.

The adsorption capacities of the adsorbents of examples 15, 16 and 17 for real fuel JP-5 with 1040 ppmw of sulfur also are evaluated in the batch system described above. The adsorptive capacities of the adsorbents are shown in Table 8.

Table 8

The adsorption capacities of the adsorbents of examples 15, 16 and 17 for real fuel JP- 5 with 1040 ppmw of sulfur are also evaluated in the fixed-bed flow system. The adsorption is conducted at room temperature and 1.2 h^"1 of LHSV. The adsorptive capacities of the adsorbents at different breakthrough sulfur levels are shown in Table 9.

Table 9

The breakthrough sulfur level

Claims

Claims:

1. A method for removing sulfur compounds from a hydrocarbon fuel feedstock comprising, contacting the feedstock with a regenerable adsorbent material capable of selectively removing sulfur compounds present in the hydrocarbon feedstock wherein the contacting is performed at a temperature of about 0 ⁰C to about 100 ⁰C at a pressure of about 0.05 MPa to about 0.20 MPa and wherein the regenerable sorbent material comprises a compound of the formula Ti_xCe_yO₂ where 0<x/y _< 1 and where 0<x-$l and 0<y<l.

2. The method of claim 1 where x/y =1/9.

3. The method of claim 1 where x/y =0.5/0.5

4. The method of claim 1 where x/y =9/1.

5. The method of claim 1 where the adsorbent further comprises Pd.

6. The method of claim 1 where the temperature is about 5 ⁰C to about 70 ⁰C and the pressure is about 0.10 MPa to about 0.15 MPa.

7. The method of claim 1 where the temperature is about 25 ⁰C.

8. A method for removing sulfur compounds from a hydrocarbon fuel feedstock comprising,

Contacting the feedstock with a regenerable adsorbent material capable of selectively removing sulfur compounds present in the hydrocarbon feedstock wherein the contacting is performed at a temperature of about 0 ⁰C to about 100 ⁰C at a pressure of about 0.05 MPa to about 0.20 MPa and wherein the regenerable sorbent material comprises a compound of the of the formula MO-CeO₂ where M is any of Ag, Au, Ba, Be, Ca, Co, Cr, Cu, Fe, Ge, Hf, Ir, La, Mg, Mo, Ni, Os, Pb, Pd, Pl, Rh, Ru, Sc, Sn, Sr, Ti W, Y₂, Zr and mixtures thereof.

9. The method of claim 8 wherein the temperature is about 5 ⁰C to about 70 ⁰C and the pressure is about 0.10 MPa to about 0.15 MPa.

10. The method of claim 8 wherein the temperature is about 25 ⁰C.

11. A compound suitable for selectively adsorbing sulfur compounds from a hydrocarbon fuel feedstock over a temperature range of about 0 ⁰C to about 100 0C wherein the compound has the formula Ti_xCe_yO₂ where 0<x/y <, 1 and where 0<x < l and 0<y< l.

12. The compound of claim 11 where x/y = 1/9.

13. The compound of claim 11 where x/y =0.5/0.5

14. The compound of claim 11 where x/y =9/1.

15. The compound of claim 11 where the adsorbent further comprises Pd.

16. A compound suitable for selectively adsorbing sulfur compounds from , A hydrocarbon fuel feedstock over a temperature range of about 0 ⁰C to ,about 100 0C wherein the compound comprises a compound of the formula MO^CeO₂ where M is any of Ag, Au, Ba, Be, Ca, Co, Cr, Cu, Fe, Ge, Hf, Ir, La, Mg, Mo, Ni, Os, Pb, Pd, Pt, Rh, Ru, Sc, Sn, Sr, Ti W, Y₂, Zr and mixtures thereof.

17. The method of claim 8 wherein the temperature is about 5 ⁰C to about 70 ⁰C and the pressure is about 0.10 MPa to about 0.15 MPa.

18. The method of claim 8 wherein the temperature is about 25 ⁰C.