DBT) And 4,6-dimethyldibenzothiophene Research Articles

Intraparticle ripening to create hierarchically porous Ti-MOF single crystals for deep oxidative desulfurization.

The catalytic oxidative desulfurization (ODS) technique is able to remove sulfur compounds from fuels, conducive to achieving deep desulfurization for the good of the ecological environment. Ti-based metal-organic frameworks (Ti-MOFs) possessing good affinity to organic reactants and considerable numbers of Ti active sites are promising catalysts for ODS. However, current Ti-MOFs suffer from severe diffusion limitations caused by the size mismatch between sole micropores and bulky sulfur compounds, leading to poor ODS performance. Here, a facile method of intraparticle ripening without any additive is developed to obtain hierarchically meso-microporous Ti-MIL-125 single crystals (Meso-Ti-MIL-125) for the first time. Such Meso-Ti-MIL-125 shows a BET surface area of 1401 m2 g-1 and a mesoporous volume that is 1.7 times as high as that of the conventional Ti-MIL-125. Our novel Meso-Ti-MIL-125 exhibits excellent catalytic performance in the ODS of a series of bulky thiophenic sulfur compounds, completely removing benzothiophene (BT), dibenzothiophene (DBT), and 4,6-dimethyldibenzothiophene (DMDBT) from model fuels, which is, respectively, 2.4 times, 1.5 times, and 6.7 times higher than the removal achieved with conventional Ti-MIL-125. Such a facile synthetic strategy is envisioned to be applied in many kinds of crystalline materials, such as zeolites, for industrial production.

Efficient adsorptive removal of dibenzothiophenes from liquid fuel over a novel triangular Ag(I) complex

The use of a π-acidic triangular silver(I) pyrazolate (Ag3pz3) as an adsorbent for adsorptive desulfurization (ADS) has been investigated in this report. Ag3pz3 shows very strong adsorptive affinity for aromatic sulfur compounds with the maximum adsorption capacity at 298 K being 58.5 and 51.5 mg S/g for dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (DMDBT), respectively. This adsorbent (used in the form of Ag3pz3·toulene) can reduce the S-content in iso-octane containing DBT or DMDBT from 100 mg S/L to ∼ 1 mg S/L after a static adsorption with an adsorbent dose of 4.52 g/L at 298 K. The adsorption mechanism can be well understood on the basis of weak intermolecular interactions, supported via the single-crystal structural determination and theoretical study. Ag3pz3 would represent a new type of adsorbent, which may find use in the adsorptive removal of dibenzothiophenes to achieve ultra-deep desulfurization.

Kinetic modeling of deep hydrodesulfurization of dibenzothiophenes on NiMo/alumina catalysts modified by phosphorus

A series of NiMo/alumina catalysts modified with phosphorus was prepared and evaluated in a trickle-bed high-pressure flow micro-reactor. The kinetics of deep hydrodesulfurization (HDS) of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (DMDBT) was investigated based on conversion and products distribution data. The estimated parameters obtained were statistically significant, suggesting an accurate representation of the system. Phosphorus addition led to a two-fold increase in the formation of direct desulfurization over hydrogenation products for the HDS of DBT. On the other hand, the HDS of DMDBT increased mainly due to an increase in the hydrogenation route, leading to high yields of hydrogenated products. The observed phenomena were described well by the estimated parameters and may be related to an increase in metal dispersion, formation of more active sites and enhancement in Brønsted acidity in the catalyst upon phosphorus addition.

New Gas-Phase Catalytic Oxidative Processes for Desulfurization of Diesel Fuel

<p>An effective gas-phase oxidative desulfurization (ODS) process was proposed. The process was studied in a laboratory reactor with a proprietary catalyst at 300-400 ºС and ambient pressure with model fuels represented by thiophene, dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (DMDBT) dissolved in octane, isooctane or toluene. The reactivity of different sulfur containing molecules in ODS was shown to increase in the sequence: thiophene < DBT < DMDBT. The main sulfur containing product of oxidation of these compounds was SO<sub>2</sub>. During the gas-phase ODS both processes of sulfur species oxidation and processes of their adsorption were observed and studied. Based on the conducted studies, different ODS process designs comprising its integration with adsorption and regeneration processes and with conventional hydrodesulfurization (HDS) process were proposed. One scheme is based on alternating regimes of ODS and catalyst regeneration in two reactors: sulfur is removed from organic feedstock by oxidation and adsorption in one reactor while simultaneous regeneration of the catalyst that has accumulated sulfur compounds takes place in another reactor. Two other schemes are based on joint use of ODS and HDS. The conventional HDS process is most effective for removal of low-boiling sulfur containing compounds reactive with respect to hydrogen, while removal of refractory sulfur compounds, such as DMDBT is more easily achieved by gas phase ODS. Thus the combination of these processes is expected to be most efficient for deep desulfurization of diesel fuel.</p>

Effect of aromatics on the adsorption of thiophenic sulfur compounds from model diesel fuel by activated carbon cloth

The effects of aromatic compound presence in real diesel fuel on the adsorption of sulfur species onto activated carbon cloth (ACC) were investigated. Equilibrium and kinetics adsorption of benzothiophene (BT), dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (DMDBT) in the presence of naphthalene (NP) and 1-methylnaphthalene (1-MNP) from prepared model diesel fuels onto ACC and its oxidized forms were studied. The total sulfur concentration in model diesel fuel was 300ppmw. The initial carbons were characterized using BET analysis, elemental analysis and thermal analysis. The selectivity for thiophenic compound adsorption were calculated with NP as reference. For each adsorbent, the selectivity of adsorption follows the order: DMDBT>DBT>1-MNP≈BT≈NP. The adsorption data fitted well with the Langmuir–Freundlich model. Aromatic compounds (arenes) show an inhibiting effect on sulfur compound adsorption by ACCs. The characterization of kinetic adsorption data indicated that both modified pseudo-n-order and mixed-order rate equations can describe the adsorption rate of all components present in the model fuels onto ACCs quite well. The results show that the rate of adsorption of sulfur compounds by ACCs in the presence of arenes is not affected.

Desulfurization of Model Diesel Fuel on Activated Carbon Modified with Iron Oxyhydroxide Nanoparticles: Effect of tert-Butylbenzene and Naphthalene Concentrations

Commercially activated carbon Filtrasorb 400 (F400) was modified with iron oxyhydroxide nanoparticles and tested, in a continuous process, as a diesel fuel desulfurization medium. Model diesel fuel (MDF) was prepared as a mixture of decane and hexadecane, with 20 ppm of sulfur from dibenzothiophenes (dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (DMDBT)), and different concentrations of tert-butylbenzene and naphthalene. The calculated selectivities and adsorption capacities for DBT and DMDBT were analyzed at different concentration of aromatics. The results indicate that, while the concentration of naphthalene greatly affects the adsorption capacity of both DBT and DMDBT, the concentration of tert-butylbenzene only affects DMDBT uptake. At low concentration of aromatics, iron-containing carbon performs better than unmodified carbon and further oxidized species were identified on the surface of the iron-modified activated carbon. This indicates that iron is acting as an acidic center, attracting basic DBT and DMDBT, and is acting as an oxidant for the adsorbed species. With an increase in the content of aromatics in MDF, the difference in the desulfurization performance between the studied materials diminishes. After thermal regeneration of the iron-containing sample, 95% of the pore volume is recovered and only a 10% loss in the DBT and DMDBT adsorption capacity is observed.

Analysis of factors affecting visible and UV enhanced oxidation of dibenzothiophenes on sulfur-doped activated carbons

Commercial wood-based activated carbon was treated with hydrogen sulfide at 650 and 800°C to introduce sulfur to the carbon matrix. On the initial and S-doped samples adsorption of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (DMDBT) from model diesel fuel with equal molar concentrations of these species was measured at room temperature. The amount adsorbed increased with an increase in the content of sulfur and in the volume of pores similar in sizes to the adsorbates molecules. This increase was attributed to the dispersive interactions in small pores that are enhanced by the presence of sulfur. Then the carbons with adsorbed DBT and DMDBT were exposed to UV, visible light and stored in dark. On the surface of sulfur-doped carbons an extensive oxidation of both DBT and DMDBT species was detected upon exposure either in UV or visible light. The photoactivity was linked to the effect of sulfur functionalities. That sulfur, besides decreasing the energy gap, increases the ability of carbons to adsorb oxygen and its reduction to active superoxygen ion. Another important factor is the affinity of carbons to retain water, which is the source of active radicals formed upon absorption of photons.

Visible light photoactivity of sulfur and phosphorus doped nanoporous carbons in oxidation of dibenzothiophenes

Polymer-derived sulfur and phosphorus doped activated carbon and commercial phosphoric acid activated carbon were used as adsorbents of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (DMDBT) from model diesel fuel (MDF). The experiments were carried out in dark, and under visible light and UV irradiations. Extraction of the products of surface reactions showed oxidation of DBT and DMDBT to sulfoxides, sulfones and other oxygen containing derivatives. The comparable results in UV and visible light demonstrate photoactivity of sulfur and phosphorus containing activated carbons in ambient conditions. Oxygen from surface groups and photogenerated holes and electrons are involved in surface reactions.

Thermal regeneration of the metal organic frameworks used in the adsorption of refractory organosulfur compounds from liquid fuels

The Metal Organic Framework (MOF) C300 system was used as a sorbent of benzothiophene (BT), dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (DMDBT) from simulated diesel fuel at constant temperature (304K) and initial sulfur concentration (1724ppm). Once thermodynamic equilibrium had been reached, thermal regeneration under inert flow within the temperature range 373–473K was attempted and a second adsorption isotherm was recorded under exactly the same experimental conditions as the previous one. Regeneration at 473K for all studied organosulfur compounds was only partial as shown by the lower level of adsorption regarding the fresh C300 sorbent. The recovered adsorption capacity was found to be a function of the boiling point of the three adsorbates, which means that the protocol employed to desorb the organosulfur compound (473K, inert flow) allows only a fraction of the adsorbed phase to be desorbed, smaller for the S-containing molecules with a higher boiling point compound. In addition, it has been observed that the adsorption capacity recovered after the first cycle is maintained for further regeneration cycles. Adsorption of the sulfur compound is very strong, as shown by the slight drop in crystallinity and by the observation of a certain fraction of oxidized species (S(VI) moieties), as confirmed by the photoelectron spectra of the regenerated sorbent.

Investigation of the Thermal Regeneration Efficiency of Activated Carbons Used in the Desulfurization of Model Diesel Fuel

Adsorption of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (DMDBT) from model diesel fuel (MDF) was investigated on a thermally regenerated wood-based carbon and two polymer-derived carbons. The materials were characterized by thermal analysis, potentiometric titration, elemental analysis, adsorption of nitrogen, and mass spectroscopy. The selectivities of DBT and DMDBT were calculated using naphthalene as a reference. The regenerated carbons were found to be very good adsorbents for the desulfurization of MDF. Although most sulfur-containing compounds were adsorbed in the micropores, where dispersive forces govern the adsorption process, DBT and DMDBT were also retained in the larger pores as a result of acid–base and/or polar interactions. This increases the overall adsorption capacity and selectivity. Moreover, thermal regeneration of carbons containing acidic oxygen groups increases their sulfur content and, thus, the contribution of specific adsorption forces involving sulfur–sulfur interactions in both small and larger pores. A significant quantity of the DBT and DMDBT adsorbed in pores larger than 10 Å is oxidized to sulfoxides and sulfones. Sulfur functional groups likely promote this process through oxygen activation.

Removal of thiophenic compounds from liquid fuel by different modified activated carbon cloths

The adsorption behavior of benzothiophene (BT), dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (DMDBT) from n-heptane was investigated onto activated carbon cloth (ACC) and its modified forms at 30 °C in batch condition. ACC was modified by HNO 3, (NH 4) 2S 2O 8, H 2SO 4, HCl and NaOH at ambient temperature. The adsorbents were characterized using nitrogen adsorption/desorption. It was found that the adsorbents are mainly microporous but differ in their surface chemistry, which is related to the effect of oxidizing agent. The adsorption process was studied from both equilibrium and kinetics point of view. The equilibrium experimental data were fitted to the Langmuir, Freundlich and Langmuir–Freundlich by non-linear method. Among the tested adsorbents, the modified ACC with HNO 3 (ACC-HNO 3) had the highest capacity for adsorption of DBT. Kinetic characterization of the adsorption process indicated that the mixed-order and modified pseudo-n-order models can describe the kinetics of adsorption of thiophenic compounds onto ACCs. The ACC and ACC-HNO 3 were used to test the removal efficiency of total sulfur contents (BT, DBT and DMDBT, 150 ppmw for each of them), too. The effect of shaking and ultrasound methods and also temperature and time on the regeneration of saturated ACC-HNO 3 with DBT was studied.

Role of phosphorus in carbon matrix in desulfurization of diesel fuel using adsorption process

Adsorptive removal of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (DMDBT) from model diesel fuel with 20ppmw total concentration of sulfur was investigated on polymer-derived carbons with incorporated heteroatoms of oxygen, sulfur and phosphorus. The materials before and after exposure to model diesel fuel were characterized using adsorption of nitrogen, thermal analysis, potentiometric titration, XPS and elemental analysis. The selectivities for DBT and DMDBT adsorption were calculated with reference to naphthalene. The results indicated that the presence of phosphorus, especially in the form of pyrophosphates and P2O5, increases the capacity and selectivity for removal of dibenzothiophenes. It also affects the adsorption mechanism. Phosphorus suppresses oxidation reactions of DBT and DMDBT. Owing to a possible location of bulky phosphorus groups in pore with sizes between 1 and 3nm thiophenic molecules are strongly adsorbed there via dispersive forces. Acidic environment also enhances adsorption via acid–base interactions. Physical adsorption mechanism and stability of surface make these carbons attractive candidates for thermal regeneration.

Removal of dibenzothiophenes from model diesel fuel on sulfur rich activated carbons

Adsorption of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (DMDBT) from model diesel fuel with 20ppmw total concentration of sulfur was investigated on commercial wood based carbon exposed to hydrogen sulfide at 650°C and 800°C. The initial and exhausted carbons were characterized using adsorption of nitrogen, thermal analysis, potentiometric titration, FTIR, mass spectroscopy, and elemental analysis. The selectivities for DBT and DMDBT adsorption were calculated with reference to naphthalene. The results showed a marked positive effect of sulfur incorporated to the carbon matrix on the capacity and selectivity for DBT and DMDBT removal from model diesel fuel. This was linked to possible sulfur–sulfur interactions in the whole range of pores. Sulfur in the carbon matrix also contributes to activation of oxygen and oxidation of DBT to sulfoxides and sulfones. Owing to this, not only micropores but also larger pores are active in the selective adsorption.

Desulfurization of Hydrocarbons by Electron Transfer Oxidative Polymerization of Heteroaromatic Sulfides Catalyzed by H5PV2Mo10O40 Polyoxometalate

The removal of sulfur-containing compounds from petroleum products such as gasoline, diesel oil, and jet fuel is an important part of the petroleum refining industry. Most sulfur-containing compounds are removed by hydrodesulfurization (HDS), in which H2 gas is used to form hydrocarbons and H2S. [1] Some sulfur-containing compounds, notably dibenzothiophene and its alkylated derivatives, are refractory towards HDS and require (very) high reaction temperatures and pressures to be effective. Because environmental considerations and requirements mandate the removal of sulfur from fuels, so called “deep” HDS of refractory sulfur compounds is both difficult and expensive. Alternative “deep” desulfurization without H2, or high pressure or temperature, is desirable, and in recent years other techniques have been suggested to remove sulfurcontaining compounds from commercial fuels. Alternative methods that have been suggested include: (1) the relatively facile catalytic oxidation of sulfides by hydrogen peroxide or organic hydroperoxides, such as tert-butyl hydroperoxide, to yield sulfones. Numerous homogeneous and heterogeneous catalysts have been described in the literature. The sulfones formed then need be removed from the fuel product by either extraction, distillation, decomposition, or adsorption. Organic hydroperoxides are expensive and the use of hydrogen peroxide implies working with water, which then requires careful drying of the fuel ; (2) selective adsorption of refractory sulfides over solids, such as Cu-Y zeolite or S Zorb SRT (a zinc oxidebased reactive sorbent) ; (3) selective extraction, for example by using ionic liquids; (4) biodesulfurization; and (5) photo-oxidation. As part of our studies on electron transfer oxidations catalyzed by the H5PV V 2Mo10O40 polyoxometalate, we have recently found that H5PV V 2Mo10O40 catalyzes the electron transfer transfer–oxygen transfer oxidation of sulfides, RSR’ (R, R’=aryl, alkyl), to yield sulfoxides, RS(O)R’. The reactions take place by initial formation of a cation radical, RSR’+C, and a reduced polyoxometalate, H5PV VMo10O40. RSR’+C is then oxygenated by oxygen transfer from the polyoxometalate (Scheme 1). Interestingly, we observed that heteroaromatic sulfides, that is, thiophene derivatives, were not oxygenated, presumably due to their stability. We now report that such heteroaromatic thiophenes, such as benzothiophene (BT), dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (DMDBT), can be oxidatively polymerized by H5PV V 2Mo10O40 supported on an inert matrix such as silica. The polymer formed is adsorbed or deposited onto the solid and in this way these heterogeneous catalysts can be used to remove refractory aromatic sulfides from hydrocarbons down to nondetectable levels. The catalyst can be regenerated by pyrolysis at 300–350 8C. In preliminary experiments benzothiophene (84 mm) was reacted with H5PV2Mo10O40 (30 mm) dissolved in acetic acid (1 mL) at 70 8C for 1 h. Different from a reaction using thioanisole as substrate, no sulfoxide was formed but benzothiophene was almost completely consumed and a brown–black insoluble material was formed. Similarly, mixing benzothiophene with H5PV2Mo10O40 at 22 8C yielded a green solution, the UV/Vis spectrum of which indicated the formation of a reduced polyoxometalate: H5PV VMo10O40. Thus, a reaction pathway can be assumed in which H5PV2Mo10O40 can activate benzothiophene by electron transfer to yield a benzothiophene cation radical (Scheme 2). The benzothiophene cation radical

Enhancement in Dibenzothiophene Reactive Adsorption from Liquid Fuel via Incorporation of Sulfur Heteroatoms into the Nanoporous Carbon Matrix

Adsorption of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (DMDBT) from simulated diesel fuel was investigated with polymer-derived carbon matrices. Sulfur was incorporated to the carbon surface via a high-temperature hydrogen sulfide reduction of oxygen-containing groups. The resultant carbons were characterized by nitrogen adsorption, thermal analysis, potentiometric titration, and elemental analysis. The selectivities for DBT and DMDBT adsorption were calculated with reference to naphthalene. The carbon matrices studied had comparable structures, hence, the effects of the sulfur functionalities were evident in an increase in dibenzothiophenes selectivity and the breakthrough capacity; this was especially visible at a breakthrough point where small pores are expected to be active in the adsorption process. Incorporation of sulfur atoms into the aromatic rings of the carbon matrix increases the ability of the surface to attract dibenzothiophenes via dispersive interactions (sulfur-sulfur bridges). Sulfur and sulfur-oxygen groups present in larger pores enhance the amount of adsorbed dibenzothiophenes via specific acid-base and polar interactions. They also contribute to the reactive adsorption of DBT and DMDBT (oxidized) and their chemisorption on the carbon surface.

Investigation of the enhancing effects of sulfur and/or oxygen functional groups of nanoporous carbons on adsorption of dibenzothiophenes

Adsorption of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (DMDBT) from simulated diesel fuel with 20 ppm w total concentration of sulfur was investigated on polymer-derived carbon containing various amounts of oxygen and sulfur incorporated to the surface. Initial and exhausted carbons were characterized using adsorption of nitrogen, thermal analysis, potentiometric titration, XPS, mass spectroscopy and elemental analysis. Selectivities for DBT and DMDBT adsorption were calculated with reference to naphthalene. It was found that both the capacity and selectivity for DBT and DMDBT removal from model diesel fuel were affected by the content and arrangement of heteroatoms. Although both oxygen and sulfur containing groups enhance the capacity, the enhancing effects of surface chemistry were more pronounced on the carbon with sulfur incorporated to its matrix. This is linked to sulfur–sulfur interactions.

Linker-Directed Vertex Desymmetrization for the Production of Coordination Polymers with High Porosity

Five non-interpenetrated microporous coordination polymers (MCPs) are derived by vertex desymmetrization using linkers with symmetry inequivalent coordinating groups, and these MCPs include properties such as rare metal clusters, new network topologies, and supramolecular isomerism. Gas sorption in polymorphic frameworks, UMCM-152 and UMCM-153 (based upon a copper-coordinated tetracarboxylated triphenylbenzene linker), reveals nearly identical properties with BET surface areas in the range of 3300-3500 m(2)/g and excess hydrogen uptake of 5.7 and 5.8 wt % at 77 K. In contrast, adsorption of organosulfur compounds dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (DMDBT) shows remarkably different capacities, providing direct evidence that liquid-phase adsorption is not solely dependent on surface area or linker/metal cluster identity. Structural features present in MCPs derived from these reduced symmetry linkers include the presence of more than one type of Cu-paddlewheel in a structure derived from a terphenyl tricarboxylate (UMCM-151) and a three-bladed zinc paddlewheel metal cluster in an MCP derived from a pentacarboxylated triphenylbenzene linker (UMCM-154).

Adsorption of dibenzothiophenes on activated carbons with copper and iron deposited on their surfaces

Three polymer-derived carbons with iron and different amounts of copper on the surface were investigated as adsorbents of dibenzothiophene (DBT) and 4, 6-dimethyldibenzothiophene (DMDBT) from simulated diesel fuel. To characterize the initial and exhausted carbons nitrogen adsorption, elemental analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermal analysis (TA) were applied. The selectivities for DBT and DMDBT were calculated with reference to naphthalene. In spite of the enhancement in selectivity for DBT and DMDBT removal caused by iron and copper species, the results indicate that the volume of micropores is the main factor governing the amount adsorbed. Oxidation of benzothiophenes is likely promoted by iron oxide and copper/copper oxide highly dispersed on the surface. The oxidation products are then selectively adsorbed on the surface of carbon in larger pores where metal species and heteroatoms are the active centers for adsorption of polar species.

Removal of refractory organosulfur compounds via oxidation with hydrogen peroxide on amorphous Ti/SiO2 catalysts

Efficient removal of benzothiophene (BT), dibenzothiophene (DBT) and 4,6-dimethyl dibenzothiophene (DMDBT) has been successfully achieved via oxidation with hydrogen peroxide in liquid phase using an amorphous silica-loaded titanium oxide catalyst. Both BT and DBT are easily oxidized to the corresponding sulfones, however in the case of DMDBT the steric hindrance of the alkyl groups makes the approach of the S-atom to the catalyst active centre (an isolated Ti(IV) species) difficult and therefore its reactivity is inhibited. The concentration of the organosulfur compound, the H2O2 concentration and the nature of the solvent play a key role in the rate of S-removal.

Enabling Cleaner Fuels: Desulfurization by Adsorption to Microporous Coordination Polymers

Microporous coordination polymers (MCPs) are demonstrated to be efficient adsorbents for the removal of the organosulfur compounds dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (DMDBT) from model diesel fuel and diesel fuel. For example, packed bed breakthrough experiments utilizing UMCM-150 find capacities of 25.1 g S/kg MCP for DBT and 24.3 g S/kg MCP for DMDBT from authentic diesel indicating that large amounts of fuel are desulfurized before the breakthrough point. Unlike activated carbons, where selectivity has been a problem, MCPs selectively adsorb the organosulfur compounds over other, similar components of diesel. Complete regeneration using toluene at modest temperatures is achieved. The attainment of high selectivities and capacities, particularly for the adsorption of the refractory compounds that are difficult to remove using current desulfurization techniques, in a reversible sorbent indicates that fuel desulfurization may be an important application for MCPs.