Tert-butyl Mercaptan Research Articles

Mercaptans in malodorants break disulfide bridges in human serum albumin and form adducts suitable as biomarkers of exposure in vitro.

Malodorants comprise notoriously smelling mercaptans and might be applied for crowd control. Because exposure to malodorants may lead to irritation of the respiratory system, choking, and coma, bioanalytical verification of poisoning might be required in a medical and forensic context. We herein present the detection and identification of novel biomarkers of exposure to ethyl mercaptan, n-butyl mercaptan, tert-butyl mercaptan, and iso-amyl mercaptan. These alkyl thiol compounds were found to form disulfide adducts in human serum albumin (HSA) in plasma in vitro with the only non-disulfide-bridged Cys34 residue and with other residues being part of the disulfide-bridged pattern in HSA. After proteinase K-catalyzed proteolysis, adducts of all mercaptans were detected simultaneously as the tripeptide Cys34*ProPhe and the dipeptides Cys369*Tyr, ValCys316*, and Cysx*Ala (x denominates either Positions 91, 200, 253, 361, and/or 448) by a sensitive micro-liquid chromatography-electrospray ionization tandem mass spectrometry (μLC-ESI MS/MS) method working in the scheduled multiple reaction monitoring (sMRM) mode. Time- and concentration-dependent adduct formations while exposure and proteolysis were investigated and the suitability of adducts as biomarkers of exposure was elaborated. Adducts at Cys34 showed the lowest limits of identification (LOIs, 6nM to 1.2μM mercaptan in plasma) and superior stability in plasma at 37°C. Therefore, Cys34*ProPhe appears as the most promising target to prove exposure to mercaptans at least in vitro.

Downstream natural gas composition across U.S. and Canada: implications for indoor methane leaks and hazardous air pollutant exposures

Previous research has shown that natural gas (NG) leaks from residential appliances are common, affecting greenhouse gas emission inventories and indoor air quality. To study these implications, we collected and analyzed 587 unburned NG samples from 481 residences over 17 North American cities for hydrocarbons, hazardous air pollutants, and organosulfur odorants. Nearly all (97% of) gas samples contained benzene (between-city mean: 2335 ppbv [95% CI: 2104, 2607]) with substantial variability between cities. Vancouver, Los Angeles, Calgary, and Denver had at least 2x higher mean benzene concentrations than other cities sampled, with Vancouver exhibiting a nearly 50x greater mean benzene level than the lowest-concentration city (Boston). We estimate that current U.S. and Canadian emissions inventories are missing an additional 25 000 [95% CI: 19 000, 34 000] and 4000 [95% CI: 3700, 5200] lbs benzene yr−1 through downstream NG leakage, respectively. Concentrations of odorants added for leak detection varied substantially across cities, indicating a lack of standardization. Houston, for instance, had 5x higher mean tert-butyl mercaptan levels than Toronto. Using these odorant measurements, we found that methane emissions as high as 0.0080–0.28 g h−1 and indoor benzene enhancements 0.0096–0.11 ppbv could go undetected by persons with an average sense of smell, with large uncertainties driven by smelling sensitivity, gas composition, and household conditions. We also observed larger leaks (>10 ppm ambient methane) in ∼4% of surveyed homes, confirming that indoor leakage occurs at varying degrees despite the presence of odorants. Overall, our results illustrate the importance of downstream NG composition to understand potential emissions, exposures, and odor-mediated leak detection levels. Given methane’s global warming potency, benzene’s toxicity, and wide variation in smelling abilities, our findings highlight the deficiencies regarding the sole reliance on odorization to alert and protect all occupants from indoor leaks.

Disulfide-adducts with cysteine residues in human serum albumin prove exposure to malodorous mercaptans in vitro

Malodorants are mixtures containing mercaptans, which trigger the flight instinct upon exposure and might thus be deployed in military and civilian defense scenarios. Exposure to mercaptans might lead to unconsciousness, thus representing a possible threat for health. Therefore, we developed and validated a bioanalytical procedure for the simultaneous detection and identification of corresponding biomarkers for the verification of exposure to mercaptans. Disulfide-adducts of ethyl mercaptan (SEt), n-butyl mercaptan (SnBu), tert-butyl mercaptan (StBu) and iso-amyl mercaptan (SiAm) with cysteine (Cys) residues in human serum albumin (HSA) were formed by in vitro incubation of human plasma. After pronase-catalyzed proteolysis, reaction products were identified as adducts of the single amino acid Cys and the dipeptide cysteine-proline (Cys34Pro) detected by a sensitive μLC-ESI MS/MS method working in the scheduled multiple reaction monitoring (sMRM) mode. Dose-response studies showed linearity for the yield of Cys34Pro-adducts in the range from 6 nM to 300 μM of mercaptans in plasma and limits of identification (LOI) were in the range from 60 nM to 6 μM. Cys34-adducts showed stability for at least 6 days in plasma (37 °C). The presented disulfide-biomarkers expand the spectrum for bioanalytical verification procedures and might be helpful to prove exposure to malodorants.

Adsorption behavior and mechanism of ultra-low concentration sulfur compounds in natural gas on Cu-impregnated activated carbon

Sulfur compounds critically deteriorate the performance of catalysts and fuel cells in H2 production and natural gas applications. This study aims to elucidate the adsorption characteristics of low-concentration tetrahydrothiophene (THT) and tert-butyl mercaptan (TBM) in CH4 (4.5 ppmv) on Cu-impregnated activated carbon (Cu/AC) by analyzing the state of the Cu and sulfur species during dynamic tests of the 1st desulfurization, regeneration and 2nd desulfurization. Physical adsorption was dominant in THT removal, enabling facile regeneration by the N2 thermal treatment at 100 °C. TBM removal was primarily carried out by the chemical adsorption utilizing CuO, Cu2O, and oxygen on the AC. During desulfurization, CuO acts as a catalyst, an adsorption site, and an oxygen donor. CuO was actively consumed during the initial stage, leading to the complete removal of the TBM. During desulfurization, oxidation to form organic sulfur and copper sulfonate was the primary reaction in the presence of sufficient amounts of CuO and oxygen on the AC. As the oxygen content of AC was consumed with subsequent desulfurization, reactive adsorption on Cu2O to form thiolate became one of the major reactions. Owing to the strong chemisorption of sulfur compounds, the recovery of the removal efficiency was limited by N2 thermal regeneration. However, oxidative regeneration at 250 °C using dilute O2 flow effectively removed chemisorbed organic sulfur and thiolate. Because oxygen consumption was accompanied by both desulfurization and regeneration reactions, this method successfully restored the desulfurization performance by recovering CuO and oxygen on the AC surface and maintaining well-dispersed Cu.

Development of modified zeolite for adsorption of mixed sulfur compounds in natural gas by combination of ion exchange and impregnation

The economic and environmental benefits of natural gas in energy applications are widely known; consequently, the usage of natural gas has increased steadily with increasing environmental regulations in recent years. However, the widespread utilization of natural gas has been limited by regulations that require sulfur compounds to be added to natural gas for leak detection. Even traces of sulfur compounds can permanently poison the catalysts used for natural gas; hence, sulfur compounds should be removed for various natural gas applications. In this study, NaY-zeolites were modified by combining Cu ion-exchange and Na2O or CuO impregnation for adsorptive desulfurization. Adsorption experiments were conducted on gas mixtures containing ppm-level tetrahydrothiophene (THT) and tert-butyl mercaptan (TBM) in CH4 to compare the desulfurization performance of pristine and modified Y-type zeolites. The analysis results show that both Na2O and CuO caused changes in the acid sites and binding energies of metal atoms in the Cu ion-exchanged Y-zeolite. Na2O promoted the adsorption of TBM, while CuO inhibited it. Among the tested samples, the Cu ion-exchanged Y-zeolite containing Na2O showed the most efficient adsorption performance with a 3.97 wt% uptake for TBM, which is 30% higher than that of the Cu ion-exchanged Y-zeolite. The Cu ion-exchanged Y-zeolite containing CuO showed the lowest adsorption ability with a 2.21 wt% uptake for TBM.

Selective monitoring of natural gas sulphur-based odorant mixture of t-butyl mercaptan and methyl ethyl sulphide using an array of microfluidic gas sensors

A natural gas (NG) odorization system requires continuous monitoring as well as an optimal injection to satisfy the odorization guidelines, minimize over-odorization, and prevent hazardous gas leaks. NG consists of hydrocarbons such as methane, odorants such as tert-butyl mercaptan, and other sulphur-based VOCs such as hydrogen sulphide; therefore, selectivity is paramount for the reliable and accurate monitoring of odorants. In this study, we developed a portable device integrated with an array of five different sensors to detect a mixture of tert-butyl mercaptan and methyl ethyl sulphide for a concentration range of 1 ppm to 10 ppm. A machine learning model was developed to predict the presence and concentration of NG odorants from the sensor data. The best-performing sensors in the array achieved high sensitivity and selectivity indicators (measured using the Davies-Bouldin index) of 0.3667 (1⁄ppm) and 0.125, respectively. The sensor system achieved a classification accuracy of 98.75% between NG odorants and hydrogen sulphide, with an overall Mean Squared Error (MSE) and R2 error (for the regression model) of 0.50 and 95.16%. These results indicate that the developed portable device and the machine learning model have promising applications for the selective monitoring of NG odorants.

Home is Where the Pipeline Ends: Characterization of Volatile Organic Compounds Present in Natural Gas at the Point of the Residential End User.

The presence of volatile organic compounds (VOCs) in unprocessed natural gas (NG) is well documented; however, the degree to which VOCs are present in NG at the point of end use is largely uncharacterized. We collected 234 whole NG samples across 69 unique residential locations across the Greater Boston metropolitan area, Massachusetts. NG samples were measured for methane (CH4), ethane (C2H6), and nonmethane VOC (NMVOC) content (including tentatively identified compounds) using commercially available USEPA analytical methods. Results revealed 296 unique NMVOC constituents in end use NG, of which 21 (or approximately 7%) were designated as hazardous air pollutants. Benzene (bootstrapped mean = 164 ppbv; SD = 16; 95% CI: 134–196) was detected in 95% of samples along with hexane (98% detection), toluene (94%), heptane (94%), and cyclohexane (89%), contributing to a mean total concentration of NMVOCs in distribution-grade NG of 6.0 ppmv (95% CI: 5.5–6.6). While total VOCs exhibited significant spatial variability, over twice as much temporal variability was observed, with a wintertime NG benzene concentration nearly eight-fold greater than summertime. By using previous NG leakage data, we estimated that 120–356 kg/yr of annual NG benzene emissions throughout Greater Boston are not currently accounted for in emissions inventories, along with an unaccounted-for indoor portion. NG-odorant content (tert-butyl mercaptan and isopropyl mercaptan) was used to estimate that a mean NG-CH4 concentration of 21.3 ppmv (95% CI: 16.7–25.9) could persist undetected in ambient air given known odor detection thresholds. This implies that indoor NG leakage may be an underappreciated source of both CH4 and associated VOCs.

The Oxidative Stress of Mercaptan Odorant Due to Occupational Exposure: Adverse Effects on the Cholinergic System

Background: Tert-butyl mercaptan is one of the frequently used odorants derived from natural gases. It has been declared as a health hazard by the Occupational Safety and Health Administration (OSHA) in the USA. There is not much information available about the mercaptans long-term toxicity secondary to occupational exposure. This study was conducted to evaluate the oxidative stress caused by mercaptan odorant. Methods: The inhalation exposure of 80 maintenance workers in a gas industry was evaluated, using NIOSH 2542 and samples analyzed by gas chromatography mass spectroscopy. Also, the administrative staff were selected as the unexposed workers with matching age and work experience compared to the exposed subjects. The lipid peroxidation and ferric reducing plasma ability (FRAP), was evaluated as oxidative stress biomarkers. The acetylcholinesterase activity was also assessed for the neurological risks. Results: The tert-butyl mercaptan exposure was evaluated at average 0.01 ppm (0.005 to 0.15 ppm). There was oxidative stress in maintenance workers along with a significant increase in the lipid peroxidation, and a decrease in FRAP level (P=0.0001). The acetyl cholinesterase activity was decreased in over half of the exposed subjects, and correlated significantly with the tert-butyl mercaptan level (r=-0.4, P=0.026). Conclusion: There was a correlation between the inhibition of acetyl cholinesterase activity and the induction of oxidative stress. Based on the findings, the chronic occupational exposure to tert-butyl mercaptan was identified as a health hazard. Therefore, specific health care strategies should be developed to minimize the toxic effect of this chemical.

Rhodium(i)-catalyzed C–S bond formation via enantioselective carbenoid S–H insertion: catalytic asymmetric synthesis of α-thioesters

The first rhodium(i)-catalyzed asymmetric S–H insertion of α-diazoarylacetates with tert-butyl mercaptan using chiral diene as the ligand has been developed.

Highly efficient adsorption of thiol compounds by ZSM-5 zeolites: Governing mechanisms

Abstract The adsorption of thiol compounds (tert-butyl mercaptan and benzenethiol) on different zeolites was systematically investigated using batch experiments to reveal the governing mechanisms of this process. For this purpose, the absorption performances of a series of zeolites with different pore size distributions (ZSM-5 and Y- and β-zeolites) and surface hydrophobicities (adjusted by the Si/Al ratio) were investigated. Among the tested zeolites, ZSM-5 exhibited a significantly higher adsorption affinity to thiols, because its pore size is suitable for invoking a micropore filling effect to enhance the adsorption. Hydrophobic interaction was another key mechanism governing the adsorption of thiols on zeolites. Furthermore, pore ion exchanging of ZSM-5 by Cu(II) could effectively improve the adsorption capacity of zeolites because of the high coordination affinity of Cu(II) toward the sulfydryl in thiols. The adsorption capacity of ZSM-5 was strongly pH dependent and sharply decreased at the pKa values of the thiols. The presence of dissolved humic acid had negligible influence on thiol compounds adsorption because of the size exclusive effect of zeolites for humic acid. Moreover, all the tested zeolites exhibited a high adsorption affinity to thiols in the presence of coexisting ions (e.g., 0.02–0.20 mol/L Na+, Ca2+). The used zeolites displayed stable thiol compounds adsorption behaviors after 10 regeneration cycles. These results reflected the high potential for applying ZSM-5 zeolites in an actual water body.

Efficient Rapid Deodorization of Mercaptan-Contaminated Soil by Sono-Fenton Process: Response Surface Modeling and Optimization

The entry of mercaptans into the environment as an odor pollutant has always been considered as one of the environmental concerns. In this research, a sonochemical oxidation (sono-Fenton) method was used for rapid deodorizing of tert-butyl mercaptan (TBM) contaminated soil. The design of the experiments was conducted by CCD method and the effect of four different factors was investigated on the remediation efficiency. The complete remediation of the soil was achieved at a concentration of hydrogen peroxide equal to 1g/l, the weight ratio of iron sulfate to soil, 0.004, the sonication power of 100W, and the pollution charge of 25000 ppm. Pareto analysis showed that the factor of H2O2 concentration with an effect of 43% and sonication power with a 26% effect had the greatest effect on the efficiency of mercaptan removal. Based on the experimental results, increasing the concentration of hydrogen peroxide and sonication power through increasing hydroxyl oxidation radicals result in enhancing the removal efficiency. Further, increasing the pollution load decreases the remediation efficiency although the intensity and heat generated by the oxidation reaction increases. The fitted quadratic model with correlation coefficient of 98% can accurately predict the removal efficiency.

Fast and environmental-friendly degradation of tert-butyl mercaptan from contaminated soil using bimetallic-modified Fenton process

In this work, the fast remediation of tert-butyl mercaptan from the polluted soil via a bimetallic Fenton treatment that included Fe2+/Fe3+/Fe0/Cu2+ in the presence of gasoline was studied. The analysis of variance and the Pareto analysis resulting from the central composite design (CCD) showed that the H2O2, CuSO4, Fe3O4 nanoparticles, nano zerovalent iron (nZVI), and gasoline initial concentrations as a secondary contaminant were influential factors on the removal efficiency of tert-butyl mercaptan (with an effectiveness of 2.09%, 13.38%, 1.92%, 2.01%, and 39.73% respectively). Moreover, the interaction of H2O2/nZVI, H2O2/nFe3O4, H2O2/CuSO4, nZVI/nFe3O4, and nZVI/CuSO4 had a positive effect on removal efficiency, while nFe3O4/CuSO4 had a negative one. Surprisingly, the mixing of nZVI and nFe3O4 before adding them to the reactor did not affect the removal efficiency. The optimum conditions suggested for the maximum removal efficiency of tert-butyl mercaptan were the minimum levels of the initial gasoline concentration (2.5 %w/w), a maximum level of CuSO4 (0.12 %w/w), and an optimum concentration of H2O2, nano-ZVI, and nano-Fe3O4 (8.92 %w/v, 0.1194 %w/w and 0.0898 %w/w, respectively) in the studied intervals. This condition led to a 99.27% efficiency removal of tert-butyl mercaptan removal in 20 minutes without pH and temperature adjustments.

Continuous Measurement of Odorant Composition for Liquefied Petroleum Gas

In Chile, commercial liquefied petroleum gas (LPG) is customarily odorized with dimethyl sulfide (DMS) and tert-butyl mercaptan (TBM) at a rate of about 10 grams of odorant per 1 cubic meter of LPG. The current control of the odorization practice involves the human nose to detect the odor in some cases, and the determination of total sulfur concentration in others. None of those methods provide the speciation of the sulfur species in LPG.On the other hand, both DMS and TBM are higher boiling than propane or butane. Therefore, the odorant concentration emanating from the odorized liquid is not uniform in the vapors released. Furthermore, the gas will also be much leaner than the odorized liquid. For those reasons, the Chilean industry recommends analyzing the odorant directly from the liquid phase.To address the problem of odorant quantification at the industry this research aims to develop a reliable and objective measure for odorized LPG that allow not only verify the odorization itself but also quantify the species incorporated with the fuel, and other sulfur compounds present naturally in the LPG. In this regard, an Automated Gas Chromatograph (Auto-GC) with an electrochemical detector was coupled with an LPG valve, which continuously takes samples of 1 µL of liquid propane. The extracted sample is then vaporized and injected into the Auto-GC to be analyzed.The methodology is capable of distinguishing and quantifying distinct odorants near real-time (within 8 minutes), as well as other sulfur impurities present in the LPG such as tetrahydrothiophene (THT) and methyl mercaptan (MeSH). Typical retention times for TBM and DMS corresponded to 282 s and 418 s respectively. More importantly, the proposed method provides meaningful information to verify the optimum odorization, i.e., the minimum value to alert in case of leak and maximum level that assures efficient combustion.

Impacts of Gas Impurities from Pipeline Natural Gas on Methane Storage in Metal–Organic Frameworks during Long-Term Cycling

The development of adsorbed natural gas (ANG) technology creates opportunities for use of pipeline natural gas as clean fuel in vehicles. Metal–organic frameworks (MOFs) are one class of materials that have received considerable attention as possible adsorbents in ANG applications. We examine how accumulation of trace components from pipeline natural gas will impact the performance of MOFs in ANG during long-term cycling. Our approach combines information from grand canonical Monte Carlo (GCMC) simulations of single-component adsorption, ideal adsorbed solution theory (IAST) of multicomponent adsorption, and an isothermal model of tank cycling to assess accumulation of heavy hydrocarbons and tert-butyl mercaptan (TBM). In a series of MOFs, a reduction in deliverable energy up to 50% is observed after 200 cycles. These results highlight the importance of considering multicomponent effects during consideration of adsorbents for ANG applications.

Selective functionalization of external and internal surface of MCM-41 for adsorptive desulfurization

MCM-41 was selectively functionalized with CuO on the external surface and Cu2+ coordinated by organosilanes on the internal surface. The production of CuO and removal of template were achieved in one step, which is convenient and a save of energy. Results of transmission electron microscopy indicate the presence of CuO on outer surface of MCM-41. The successful grafting of organosilanes was confirmed by 13C and 29Si nuclear magnetic resonance. The prepared M(CuO)N(Cu) shows more comprehensive desulfurization performance due to the simultaneous and independent incorporation of CuO and copper ions. Dimethyl sulfide and dimethyl disulfide are selectively adsorbed on external surface of M(CuO)N(Cu), while tert-butyl mercaptan can be adsorbed on both external and internal surface of M(CuO)N(Cu).

Direct nuclear magnetic resonance observation of odorant binding to mouse odorant receptor MOR244-3

Mammals are able to perceive and differentiate a great number of structurally diverse odorants through the odorant's interaction with odorant receptors (ORs), proteins found within the cell membrane of olfactory sensory neurons. The natural gas industry has used human olfactory sensitivity to sulfur compounds (thiols, sulfides, etc.) to increase the safety of fuel gas transport, storage, and use through the odorization of this product. In the United States, mixtures of sulfur compounds are used, but the major constituent of odorant packages is 2-methylpropane-2-thiol, also known as tert-butyl mercaptan. It has been fundamentally challenging to understand olfaction and odorization due to the low affinity of odorous ligands to the ORs and the difficulty in expressing a sufficient number of OR proteins. Here, we directly observed the binding of tert-butyl mercaptan and another odiferous compound, cis-cyclooctene, to mouse OR MOR244-3 on living cells by saturation transfer difference (STD) nuclear magnetic resonance (NMR) spectroscopy. This effort lays the groundwork for resolving molecular mechanisms responsible for ligand binding and resulting signaling, which in turn will lead to a clearer understanding of odorant recognition and competition.

Deep desulfurization of fuel gas by adsorption on Cu-impregnated activated carbons in practical conditions

Deep desulfurization properties and characteristics of activated carbon (AC) modified by impregnation of CuCl2 were studied using simulated hydrocarbon fuels containing dimethyl sulfide (DMS), tert-butylmercaptan (TBM), and tetrahydrothiophene (THT), the typical organosulfur compounds representing sulfides, thiols, and thiophenes that exist in fuel gases. The pristine AC had limited adsorptive desulfurization performance for a ternary DMS-THT-TBM mixture feed with an early breakthrough of DMS and TBM due to its preferential adsorption of THT. The adsorption of these organosulfur species on the AC surface was intrinsically weak and competing, as indicated by their low desorption activation energies (37-39 kJ mol−1). However, relatively stronger adsorption of THT than the others led to the AC surface gradually being covered by THT through replacement of the initially adsorbed TBM and DMS. The impregnation of CuCl2 on the AC (3.4 atomic % Cu) additionally formed strong and selective adsorption sites for TBM (activation energy=58.6 kJ mol−1) on the AC surface, which gave rise to about three-fold increase in the total breakthrough adsorption capacity for these sulfur species. The structure and physicochemical properties of the adsorbents were characterized by N2 adsorption, x-ray diffraction, x-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, differential scanning calorimetry, and surface pH measurement. The results suggested that the modulation of adsorption selectivity of the AC surface by CuCl2 impregnation had significant effects on the overall deep desulfurization performance for fuel gases containing multiple organosulfur species in practical conditions.

A Comprehensive Set of High-Quality Point Charges for Simulations of Metal–Organic Frameworks

Most classical simulations of metal–organic frameworks model electrostatic interactions using point charges on each atom in the structure. We report atomic point charges derived from periodic density functional theory (DFT) electronic structure calculations for more than 2000 unique experimentally synthesized metal–organic frameworks (MOFs). These charges are publicly available as a supplement to the Computation-Ready Experimental MOF database. These DFT-derived atomic point charges are compared to semiempirical group contribution and charge equilibration methods for assigning charges. As an example of using these charges, we examined each MOF for usefulness in the adsorptive removal of tert-butyl mercaptan (TBM) from natural gas. Monte Carlo simulations revealed many candidate MOF structures with high selectivity for TBM over CH4 and high TBM capacity. We anticipate that this public data set of atomic point charges for MOFs will facilitate high-throughput screening for a wide variety of applications in w...

High performance of manganese oxide octahedral molecular sieve adsorbents for removing sulfur compounds from fuel gas

Properties of porous manganese oxide adsorbents for adsorptive removal of tert-butylmercaptan (TBM) from CH4 fuel gas were investigated at ambient temperature and atmospheric pressure. The adsorbents were prepared by oxidation reactions of Mn2+ with KMnO4 and via the sol-gel method by reduction of KMnO4 using fumaric acid as the reducing agent. The effects of preparation method, precursor, temperature, and time for the structure and desulfurization properties of the resulting adsorbents were studied. Cryptomelane octahedral manganese oxide molecular sieve (OMS-2) adsorbents exhibited high breakthrough TBM adsorption (1.3–2.5mmol g-1) with the properties varied by the synthesis condition. The OMS-2-Ac prepared by the oxidation reactions of manganese acetate resulted in smaller OMS-2 crystallites with higher surface area compared to those prepared from manganese sulfate and chloride precursors, and it exhibited an enhanced TBM adsorption uptake. TBM adsorption capacity of OMS-2 could be further enhanced by introducing Cu into the structure. This gave rise to a markedly high TBM breakthrough adsorption (7.4mmol g-1) for Cu-OMS-2 (7.8 wt% Cu doping), which is significantly greater than the values reported for activated carbon, zeolite, and other porous oxide based solid adsorbents at similar conditions in the literature.

Synthesis, characterization and desulfurization performance of MCM-41 functionalized with Cu by direct synthesis and organosilanes by grafting

Cu-incorporated MCM-41 was prepared by the direct synthesis method. The Cu-incorporated MCM-41 was then organically functionalized by grafting of organosilanes followed by the complexation of copper ions. The results of powder X-ray diffraction, Fourier transform infrared, and temperature-programmed reduction suggest the incorporation of Cu into the framework of MCM-41 during the direct synthesis process. The mesostructure of prepared samples is preserved after functionalization. The sulfur capacities for tert-butyl mercaptan, dimethyl sulfide, and dimethyl disulfide decrease in the same order (40)Cu–M > (40)Cu–M–N–Cu. The (40)Cu–M synthesized through the direct synthesis method also shows better desulfurization performance than M–Cu prepared by the incipient wetness impregnation method. This is attributed to the incorporated Cu species in the framework and well-dispersed CuO species of (40)Cu–M.