Ethanethiol Research Articles

Three-dimensionally ordered macroporous metal oxide–silica composite for removal of mercaptan

A series of 3DOM and non-3DOM metal oxide–silica composites were prepared and tested dynamically in a packed-bed reactor at room temperature to remove ethanethiol from a gas stream containing ethyl mercaptan in moist N2.The obtained sorbents were characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption–desorption techniques. The experimental results showed that the adsorption ability of different kinds of metal oxide–silica composites with 3DOM structure decreased in the sequence: 3D-CuO/SiO2 > 3D-NiO/SiO2 > 3D-Co3O4/SiO2 > 3D-ZnO/SiO2. The best ratio of CuO to SiO2 of 3DOM copper–silicon oxide sorbents for ethanethiol removal was found to be 1:2. The 3DOM structure could improve the removal activity of sorbents remarkably because of the high porosity with ordered interconnected macropores as well as the large surface area and high dispersion of CuO. It was also found that a moist atmosphere greatly benefited the adsorption of ethanethiol at ambient condition.

Equilibrium adsorption of ethyl mercaptan and thiophene using molecular sieve 13X

In the present study, adsorption of the sulfur compound onto two types of molecular sieve (HYD10B and LQ-MS-13X) in a batch system was investigated. It has been illustrated that HYD10B type has more adsorption capacity than LQ-MS-13X type to separate ethyl mercaptan from simulated liquid mixture. Selected as the better adsorbent, the isotherm equilibrium adsorptions of ethyl mercaptan and thiophene in liquid phase had been carried out by using this type of molecular sieve in the temperature range of 25–65 °C. HYD10B-MS-13X brought out the highest adsorption capacity for adsorption of ethyl mercaptan component. Diminution of adsorption capacity with temperature increment has been found and it was shown that adsorption of ethyl mercaptan is less affected by temperature changes. Using four more common isotherm models (Langmuir, Freundlich, Tempkin and Dubinin-Radushkevich), Freundlich isotherm was found to be the best representative model for describing ethyl mercaptan and thiophene equilibrium data.

Rapid labeling of amino acid neurotransmitters with a fluorescent thiol in the presence of o-phthalaldehyde.

LIF detection often requires labeling of analytes with fluorophores; and fast fluorescent derivatization is valuable for high-throughput analysis with flow-gated CE. Here, we report a fast fluorescein-labeling scheme for amino acid neurotransmitters, which were then rapidly separated and detected in flow-gated CE. This scheme was based on the reaction between primary amines and o-phthalaldehyde in the presence of a fluorescent thiol, 2-((5-fluoresceinyl)aminocarbonyl)ethyl mercaptan (FACE-SH). The short reaction time (<30 s) was suited for on-line mixing and derivatization that was directly coupled with flow-gated CE for rapid electrophoretic separation and sensitive LIF detection. To maintain the effective concentration of reactive FACE-SH, Tris(2-carboxyethyl)phosphine was added to the derivatization reagents to prevent thiol loss due to oxidation. This labeling scheme was applied to the detection of neurotransmitters by coupling in vitro microdialysis with online derivatization and flow-gated CE. It is also anticipated that this fluorophore tagging scheme would be valuable for on-chip labeling of proteins retained on support in SPE.

ChemInform Abstract: The Structure Feature of Layered M1/3TiNbO5 (M: Fe, Ce) and Their Photocatalytic Oxidization Performance for Ethyl Mercaptan.

AbstractLayered photocatalytic M1/3TiNbO5 (M: Fe, Ce) is prepared by ion‐exchange of KTiNbO5 with 2 M M(NO3)3 (96 h).

Electrochemical detection of Hg(II) in water using self-assembled single walled carbon nanotube-poly(m-amino benzene sulfonic acid) on gold electrode

This work reports on the detection of mercury using single walled carbon nanotube-poly (m-amino benzene sulfonic acid) (SWCNT-PABS) modified gold electrode by self-assembled monolayers (SAMs) technique. A thiol containing moiety (dimethyl amino ethane thiol (DMAET)) was used to facilitate the assembly of the SWCNT-PABS molecules onto the Au electrode surface. The successfully assembled monolayers were characterised using atomic force microscopy (AFM). Cyclic voltammetric and electrochemical impedance spectroscopic studies of the modified electrode (Au-DMAET-(SWCNT-PABS)) showed improved electron transfer over the bare Au electrode and the Au-DMAET in [Fe (CN)6]3−/4− solution. The Au-DMAET-(SWCNT-PABS) was used for the detection of Hg in water by square wave anodic stripping voltammetry (SWASV) analysis at the following optimized conditions: deposition potential of −0.1V, deposition time of 30s, 0.1M HCl electrolyte and pH3. The sensor showed a good sensitivity and a limit of detection of 0.06μM with a linear concentration range of 20ppb to 250ppb under the optimum conditions. The analytical applicability of the proposed method with the sensor electrode was tested with real water sample and the method was validated with inductively coupled plasma – optical emission spectroscopy.

The structure feature of layered M1/3TiNbO5 (M=Fe, Ce) and their photocatalytic oxidization performance for ethyl mercaptan

Layered photocatalytic materials M1/3TiNbO5 (M = Fe, Ce) were prepared by ion-exchange of KTiNbO5 with M(NO3)3. The parent KTiNbO5 was synthesized with titanium (IV) isopropoxide and niobium oxalate by a novel polymerized complex (PC) method. The micro-structures and spectral response features of the as-prepared samples were characterized by powder X-ray diffraction (XRD), transmission electron microscope (TEM), laser Raman spectroscopy (LRS) and UV–vis diffuse reflectance spectroscopy (UV–vis DRS). The results revealed that there was a significant interaction between the interlayer cation and the terminal NbO (TiO) bond in the NbO6 (TiO6) unit of the laminates. Photocatalytic performance was evaluated in oxidation of ethyl mercaptan under natural and UV light irradiation. It can be deduced that the photocatalytic oxidization performance can be directly affected by the characteristics of the interlayer cations.

Temperature Dependent Adsorption of Sulfur Components, Water, and Carbon Dioxide on a Silica–Alumina Gel Used in Natural Gas Processing

Adsorption is one of the key technologies for the removal of sulfur compounds in trace levels from natural gas prior to a technical utilization. To improve the design of these coupled adsorption–desorption processes a profound insight into the thermodynamics of adsorption is necessary. Therefore, this article provides adsorption isotherms of ethyl mercaptan, methyl mercaptan, hydrogen sulfide, water, and carbon dioxide on a commercial silica–alumina gel used in natural gas purification. The experimental data spans a temperature range between 25 and 300 °C at concentrations between 0 and 2000 mol-ppm at total pressure of 1.3 bar. Equilibrium capacities and isosteric heats of adsorption are compared and discussed based on an analysis of specific interactions between the adsorptives and the adsorbent’s chemical surface functionality.

Effects of mix ratio, moisture content and aeration rate on sulfur odor emissions during pig manure composting

Sulfur compounds in swine manure can cause odor emissions during composting if conditions are not conducive to their rapid oxidation and degradation. In this study, the effects of controllable composting process variables on sulfur odor emissions were investigated. These included pig manure to corn stalk mix ratio (0.7:1, 1.5:1 and 2.2:1dw basis), initial moisture content (60%, 65%, 70% and 75%) and aeration rate (1.0, 2.0, 3.0 and 4.0m3m−3h−1). The compounds measured were carbonyl sulfide, carbon disulfide, hydrogen sulfide, methyl mercaptan, ethyl mercaptan, diethyl sulfide, dimethyl sulfide (Me2S) and dimethyl disulfide (Me2SS). The results showed that total sulfur losses ranged from 3.9% to 18.3% after 26days of composting. Me2S and Me2SS were the primary (>59.61%) sulfur compounds released during this period. After turning, emission rates of both Me2S and Me2SS increased. Emissions of the other six sulfur compounds were low and inconsistent during composting. Within the compost, feedstock mix ratio significantly influenced the concentration of Me2SS, while aeration rate significantly affected Me2S concentration (p<0.05). Moisture content did not have a significant effect on the concentrations of either of these two compounds. Concentrations of sulfur odor compounds were the lowest at the highest aeration rate. Therefore, high aeration rates during the thermophilic phase, especially after turning, are recommended to minimize sulfur odors produced during swine manure composting.

Adsorptive desulfurization with metal-organic frameworks: A density functional theory investigation

The contribution of each fragment of metal-organic frameworks (MOFs) to the adsorption of sulfur compounds were investigated using density functional theory (DFT). The involved sulfur compounds are dimethyl sulfide (CH3SCH3), ethyl mercaptan (CH3CH2SH) and hydrogen sulfide (H2S). MOFs with different organic ligands (NH2-BDC, BDC and NDC), metal centers structures (M, M-M and M3O) and metal ions (Zn, Cu and Fe) were used to study their effects on sulfur species adsorption. The results revealed that, MOFs with coordinatively unsaturated sites (CUS) have the strongest binding strength with sulfur compounds, MOFs with NH2-BDC substituent group ligand comes second, followed by that with saturated metal center, and the organic ligands without substituent group has the weakest adsorption strength. Moreover, it was also found that, among different metal ions (Fe, Zn and Cu), MOFs with unsaturated Fe has the strongest adsorption strength for sulfur compounds. These results are consistent with our previous experimental observations, and therefore provide insights on the better design of MOFs for desulfurization application.

Investigating the cross-interference effects of alumina refinery process gas species on a SAW based mercury vapor sensor

In this study, the effect of some common alumina refinery process gas species on the response of a surface acoustic wave (SAW) based elemental mercury (Hg0) vapor microsensor was investigated. The developed sensor was based on a SAW delay line, fabricated on a ST-cut quartz substrate with nickel (Ni) interdigitated transducer (IDT) electrodes and gold (Au) film sensitive layer. Ni was chosen as IDT material due to its immiscibility in mercury and thus allowing the sensor to operate for a longer time, as required by the industries. The sensor was exposed to mercury vapor concentrations between 24 and 365ppbv without/with the presence of ammonia, acetaldehyde, ethyl mercaptan, dimethyl disulphide, methyl ethyl ketone and humidity. The detection limit of the sensor toward Hg0 vapor was calculated to be 1.4ppbv and 4.0ppbv at operating temperatures of 35 and 75°C, respectively. The coefficient of variance of the sensor response magnitude was found to be within ±1.86 and ±5.73% at 75°C when exposed to repeated pulses of 365ppbv of Hg0 vapor without and with the presence of interfering gas species, respectively. This indicates high precision of sensor while measuring low concentrations of Hg0 vapor. Results showed that when any one of the interfering gas species was exposed along with Hg0 vapor, the response magnitude of the sensor deviated up- to 7% (93% selectivity) at an operating temperature of 75°C. Furthermore, the sensor showed a selectivity of 87% when Hg0 vapor was tested along with a mixture of all interfering gases. There was insignificant cross-sensitivity effect when the humidity content was increased within the range of 15,300 to 30,600ppmv (equivalent to 50 to 100% relative humidity at room temperature). The overall results indicate that the developed sensor is able to detect Hg0 vapor selectively even in simulated industrial conditions and can be a potentially cheaper and more reliable alternative to the current Hg0 monitoring methods used in alumina refineries.

A nanoengineered surface acoustic wave device for analysis of mercury in gas phase

We show that the nickel (Ni)-gold (Au) alloy nanostructures can be directly grown on the electrodes of a surface acoustic wave (SAW) device and can be utilized to detect toxic metal (i.e. elemental mercury (Hg0) in this case), without the requirement of the device having delay line sorption layer and thereby removing the necessity for any additional lithography steps to be undertaken. A set of SAW devices with Ni (100nm thick) electrodes were fabricated using photo-lithography and wet etching processes where each device contained 180 finger pairs in their input and output transducers with 18μm width and spacing (i.e. resonance frequency of ∼42.7MHz). Au nanostructures were then deposited on the Ni surface through galvanic replacement (GR) reaction by utilizing different HAuCl4 concentrations (i.e. 0.5mM/1mM) and reaction times (i.e. 10/20/30min). The results indicated that higher Au concentration can be utilized for acquiring smaller size of Ni-Au alloy nanostructures while the number of Au nanostructures can be increased by the control of the reaction time. It was found that the SAW device with 20min GR reaction time in 1mM HAuCl4 (1mM—20min GR SAW) solution allowed the optimum growth conditions for Ni-Au alloy nanostructures on the electrode surface for Hg0 vapor sensing. Hg0 vapor testing experiments showed that a limit of detection (LoD) of 1.3ppbv toward Hg0 vapor can be achieved with the developed 1mM—20min GR SAW device tested at 35°C. This optimum reaction conditions allowed for ∼100% and ∼200% higher response magnitudes than the 0.5mM—20min and 1mM—10min GR SAW counterparts, respectively when exposed toward low Hg0 vapor concentrations (<400ppbv). Further analysis showed that the effect of interfering gas species such as ammonia, acetaldehyde, ethyl mercaptan and humidity on the sensor’s selectivity toward Hg0 vapor can be reduced by choosing an optimum temperature of 85°C and an optimum Hg0 vapor exposure time of 6min. Overall analysis indicated that, the developed SAW based sensor holds great prospect in chemical sensing applications.

Effect of phosphorus on acidity and catalytic performance of Al-MCM-41 for the selective conversion of ethyl mercaptan to ethylene and H2S

A series of phosphorus modified Al-MCM-41 molecular sieves with various P/Al ratios were prepared via impregnating method and tested in the selective transformation of ethyl mercaptan into ethylene and hydrogen sulfide. The resulting samples were characterized by a combination of X-ray diffraction, N2 adsorption, ICP-OES, NH3 -TPD, 27Al and 31P MAS NMR spectroscopy. The experimental findings demonstrated that P modification can effectively increase the concentration as well as the strength of weak acid sites. Intermediate acid sites were gradually decreased with phosphorus addition, and the product distribution was found to vary with the acidity of the zeolites. Phosphorus content has strong influence on catalytic stability and ethylene selectivity. Upon P treatment, the amount of coke drastically decreased and the catalyst lifetime prolonged. The notable results could be useful for developing a viable process for removing ethyl mercaptan from natural gas.

The scent of death

Mary Cablk and her dog Inca spent a week last September searching the ashes of remote California towns ravaged by forest fires. They were looking for people who had died as their homes and everything in them burned to the ground. Cablk had just finished training Inca, an 18-month-old Malinois, to alert her to the presence of odors wafting from human remains. The weeklong trip from their home base in Reno, Nev., to help a California disaster response team was one of Inca’s first major assignments, literally a trial-by-fire. When they arrived at one home reduced almost entirely to ash, instead of the odor of burnt wood and smoke, Cablk and Inca were enveloped by the scent of a propane tank leak. Cablk’s heart sank. All she could smell was the sulfurous stink of ethyl mercaptan, a compound added to propane to warn humans of a tank leak. A dog’s

Adsorption Kinetics of Ethyl Mercaptan Found in Commercially Available LPG in UAE

The kinetics of adsorption of ethyl mercaptan, found in commercially available LPG, on different adsorbents, namely Zeolite, ZnO and house made date pits activated carbon (DP-AC) have been studied. The bed capacity was determined using two adsorbents weights, namely 0.2 and 0.3 g, at different LPG flow rates in the range of 35 to 90 ml min-1. It was found that the capacity of DP-AC and Zeolite did not change with the flow rate due to their much larger micropore volumes and smaller average pores sizes, compared to ZnO. The capacity of DP-AC did not even change with the amount of adsorbate used. Two kinetics models, namely Adam's-Bohart and Yoon-Nelson, were used to fit the experimental data and compared to the first order model. The first order and Adam's-Bohart models did not present the experimental data fairly well, and only the Yoon-Nelson model was able to mimic the sigmoidal trend of the breakthrough curves. The goodness of the fitting of the Yoon-Nelson model was also reflected on the values of the coefficient of determination R2, which was much closer to 1.0 compared to that of the other model. The developed models can be used in designing and scaling-up of fixed-bed adsorption columns.

Synthesis of CeO2/e-HTiNbO5 Nanocomposite and Its Application for Photocatalytic Oxidation Desulfurization

Nanoscaled CeO2/e-HTiNbO5 composite was assembled by a facile process using colloidal TiNbO[Formula: see text] (e-HTiNbO5) nanosheet and CeO2 colloid as precursors at room temperature. The nanosheet e-HTiNbO5 was obtained through proton-exchange and exfoliation process from its parent KTiNbO5. The microstructures and properties of the as-prepared samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Laser Raman spectroscopy (LRS), and UV-vis diffuse reflectance spectroscopy (UV-vis DRS), etc. The photocatalytic activity of the obtained nanocomposite is evaluated by the adsorption and photocatalytic oxidation of ethyl mercaptan (EM) under natural light irradiation. The results show that CeO2 nanoparticles are dispersed uniformly on the surface of e-HTiNbO5 and the layered structure of e-HTiNbO5 nanosheet maintains integrity. The interaction between dispersed CeO2 particles and e-HTiNbO5 results in lower bandgap compared to its precursors, and the photocatalytic activity of CeO2/e-HTiNbO5 are enhanced under natural light irradiation.

Conversion and reaction kinetics of coke oven gas over a commercial Fe−Mo/Al2O3 catalyst

Producing methanol from coke oven gas (COG) is one of the important applications of COG. Removal of sulfur from COG is a key step of this process. Conversion and reaction kinetics over a commercial Fe−Mo/Al2O3 catalyst (T-202) were studied in a continuous flow fixed bed reactor under pressures of 1.6−2.8 MPa, space time of 1.32−3.55 s and temperatures of 240−360 °C. Though the COG contains about 0.6 mol/mol H2, hydrogenation of CO and CO2 is not significant on this catalyst. The conversions of unsaturated hydrocarbons depend on their molecular structures. Diolefins and alkynes can be completely hydrogenated even at relatively low temperature and pressure. Olefins, in contrast, can only be progressively hydrogenated with increasing temperature and pressure. The hydrodesulfurization (HDS) of CS2 on this catalyst is easy. Complete conversion of CS2 was observed in the whole range of the conditions used in this work. The original COS in the COG can also be easily converted to a low level. However, its complete HDS is difficult due to the relatively high concentration of CO in the COG and due to the limitation of thermodynamics. H2S can react with unsaturated hydrocarbons to form ethyl mercaptan and thiophene, which are then progressively hydrodesulfurized with increasing temperature and pressure. Based on the experimental observations, reaction kinetic models for the conversion of ethylene and sulfur-containing compounds were proposed; the values of the parameters in the models were obtained by regression of the experimental data.

A Mechanistic Approach to the Influence of Surfactants on the Oxidation of Ethyl Mercaptan and its Dimer Ethyl Mercaptan Disulfide by Hexacyanoferrate(III) Ions in Aqueous Medium

Abstract In this paper we report on the rate of oxidation of ethyl mercaptan and its dimer ethyl mercaptan disulfide by alkaline hexacyanoferrate(III) along with its mechanistic pathway, spectrophotometrically. The influence of different experimental parameters, such as change in concentration of EtSH, HCF, OH− and reaction temperature was studdie. It was observed that the order of reaction decreases in [EtSH] or [OH−] from first order to higher concentration, but it certainly did not tend towards zero order. The effect of surfactants on the rate of reaction was observed at the critical micelle concentration (CMC) of the surfactant and reported to be below the CMC. The investigators, thus, concluded that the added products have an insignificant effect on the reaction rate. Further, the activation parameters were evaluated which lend support to the proposed mechanism. The thermodynamic quantities were also determined and the binding parameters have also been evaluated using the Menger and Portnoy model.

アンモニアとエタンチオールからなる複合臭成分の媒染染色布による除去

アンモニアとエタンチオールからなる複合臭成分の媒染染色布による除去

アンモニアとエタンチオールからなる複合臭成分の媒染染色布による除去

アンモニアとエタンチオールからなる複合臭成分の媒染染色布による除去

放電による非水溶性臭気物質の除去

This article describes the bench scale experiments (the flow rate of odor gas about 1 Nm3 /min) for removal of the water insoluble odor (ethyl mercaptan (EM) and dimethyl sulfide (DMS)) using corona discharge. The odor concentration was adjusted by the bubbling of the odors solutions diluted the excess ethanol into cooling container. The concentration of the odor was successfully controlled by the flow rate of bubbling gas (N2) and it enabled a stable experiment for a long period of time. The decomposition of EM and DMS was accomplished by the corona discharge reactor consisted of four stainless wires and achieved over 50% conversion at electric power of 15W. Furthermore, the experimental results suggested that the most of EM directly was due to decomposition into corona plasma not oxidation of the ozone produced by corona discharge. But the decrease of DMS concentration combined of discharge decomposition and ozone oxidation