Adsorptive separation of dimethyl disulfide from liquefied petroleum gas by different zeolites and selectivity study via FT-IR

Research progress on adsorption and separation of carbonyl sulfide in blast furnace gas

The iron and steel industry is one of the foundational industries in China. However, with the introduction of energy-saving and emission reduction policies, desulfurization of blast furnace gas (BFG) is also necessary for further sulfur control in the iron and steel industry. Carbonyl sulfide (COS) has become a significant and difficult issue in the BFG treatment due to its unique physical and chemical properties. The sources of COS in BFG are reviewed, and the commonly used removal methods for COS are summarized, including the types of adsorbents commonly used in adsorption methods and the adsorption mechanism of COS. The adsorption method is simple in operation, economical, and rich in types of adsorbents and has become a major focus of current research. At the same time, commonly used adsorbent materials such as activated carbon, molecular sieves, metal-organic frameworks (MOFs), and layered hydroxide adsorbents (LDHs) are introduced. The three mechanisms of adsorption including π-complexation, acid-base interaction, and metal-sulfur interaction provide useful information for the subsequent development of BFG desulfurization technology.

Mordenite-Supported Ag+-Cu2+-Zn2+ Trimetallic System: A Variety of Nanospecies Obtained via Thermal Reduction in Hydrogen Followed by Cooling in an Air or Hydrogen Atmosphere

Multimetallic systems, instead of monometallic systems, have been used to develop materials with diverse supported species to improve their catalytic, antimicrobial activity, etc., properties. The changes in the types of nanospecies obtained through the thermal reduction of ternary Ag⁺-Cu²⁺-Zn²⁺/mordenite systems in hydrogen, followed by their cooling in an air or hydrogen atmosphere, were studied. Such combinations of trimetallic systems with different metal content, variable ratios (between them), and alternating atmosphere types (during the cooling after reducing the samples in hydrogen at 350 °C) lead to diversity in the obtained copper and silver nanospecies. No reduction of Zn²⁺ was evidenced. A low silver content leads to the formation of reduced silver clusters, while the formation of nanoparticles of a bigger size takes place in the trimetallic samples with high silver content. The cooling of the reduced trimetallic samples in the air causes the oxidation of the obtained metallic clusters and silver and copper nanoparticles. In the case of copper, such conditions lead to the formation of mainly copper (II) oxide, while the silver nanospecies are converted mainly into clusters and nanoparticles. The zinc cations provoked changes in the mordenite matrix, which was associated with the formation of point oxygen defects in the mordenite structure and the formation of surface zinc oxide sub-nanoparticles in the samples cooled in the air.

Adsorption and photocatalytic conversion of ethyl mercaptan to diethyl disulfide on Fe2O3-loaded HNbMoO6 nanosheet

Ethyl mercaptans which commonly exist in natural gas need to be removed due to their toxic, odorous, and corrosive properties. Herein, a novel Fe₂O₃-modified HNbMoO₆ nanosheet catalyst (Fe₂O₃@e-HNbMoO₆) was prepared by an exfoliation-impregnation method for the ethyl mercaptans removal. In the heterojunction catalyst, e-HNbMoO₆ can be excited by visible light to generate the photogenic charge and has certain adsorption property for ethyl mercaptan with hydrogen bonding (Nb-OH or Mo-OH as the hydrogen bonding donor); Fe₂O₃ plays the role of accelerating photogenerated electrons and holes, and enhancing the adsorption of ethyl mercaptan with another hydrogen bonding (Fe-OH as the hydrogen bonding donor and receptor). Results showed that the adsorption capacity of Fe₂O₃@e-HNbMoO₆ is 69.9 μmol/g for ethyl mercaptan. In addition, the photocatalytic conversion efficiency of ethyl mercaptan to diethyl disulfide is nearly 100% and it is higher than that of the other Nb-Mo based photocatalysts, such as LiNbMoO₆, Fe_1/3NbMoO₆, Ce_1/3NbMoO₆, TiO₂-HNbMoO₆, e-HNbMoO₆, CeO₂@e-HNbMoO₆, and Ag₂O@e-HNbMoO₆. Under the experimental conditions, the photocatalytic conversion efficiency is greater than the adsorption efficiency over Fe₂O₃@e-HNbMoO₆, and there is no ethyl mercaptan output in the process of adsorption and photocatalytic conversion. Fe₂O₃@e-HNbMoO₆ heterojunction catalyst has practical value and reference significance for purifying methane gas and enhancing photocatalytic conversion of ethyl mercaptan.

Method Validation and Dissipation Behaviour of Dimethyl Disulphide (DMDS) in Cucumber and Soil by Gas Chromatography-Tandem Mass Spectrometry

In this study, a useful analytical method was developed and validated for measuring the residues of dimethyl disulphide (DMDS) in cucumbers and soil by gas chromatography-tandem mass spectrometry (GC-MS/MS). The dissipation dynamics and residual levels of DMDS in cucumber and soil were also studied in Shandong, Jilin, and Hebei provinces by using this method. Dichloromethane was selected and used as the extraction solvent to extract the target pesticide from the soil and cucumber samples. The soil and cucumber samples were cleaned up by the combination of multiwalled carbon nanotubes (MWCNT) and biochar. The average recoveries of the DMDS in cucumbers and soil were in the range of 84–101.5%, with relative standard deviations (RSD) of 0.7–4.9%, when they spiked at 0.05, 0.5, and 5 mg/kg DMDS respectively. The limit of quantification (LOQ) of this method was 0.05 mg/kg. First-order and second-order kinetic equations were used to fit dissipation data. Results show that the half-lives of DMDS in the soil at Shandong, Jilin, and Hebei were 1.63–4.47 days, 1.96–6.49 days, and 1.35–2.51 days, respectively. The final residues of DMDS were less than 0.05 mg/kg in cucumbers and 0.36 mg/kg in the soil. The dissipation rates of DMDS in different soils were different. The method provides a basis for the risk assessment of DMDS in cucumber and soil.

Dibenzyl Disulfide Adsorption on Cationic Exchanged Faujasites: A DFT Study

Although dibenzyl disulfide (DBDS) is used as a mineral oil stabilizer, its presence in electrical transformer oil is associated as one of the major causes of copper corrosion and subsequent formation of copper sulfide. In order to prevent these undesirable processes, MY zeolites (with M = Li, Na, K, Cs, Cu or Ag) are proposed to adsorb molecularly DBDS. In this study, different MY zeolites are investigated at the DFT+D level in order to assess their ability in DBDS adsorption. It was found that CsY, AgY and CuY exhibit the best compromise between high interaction energies and limited S-S bond activation, thus emerging as optimal adsorbents for DBDS.

Adsorptive removal of dimethyl disulfide from methyl tert-butyl ether using an Ag-exchanged ZSM-5 zeolite

Ag⁺-exchange improves the DMDS adsorption amount by 7.7 times compared to parent HZSM-5.

Experimental study on deep desulfurization of MTBE by electrochemical oxidation and distillation

With the increasing awareness of environmental protection, deep desulfurization of methyl tert-butyl ether (MTBE), which is the most important octane booster in gasoline, is extremely urgent.

Effect of olefin and aromatics on thiophene adsorption desulfurization over modified NiY zeolites by metal Pd

NiY and NiPdY adsorbents were prepared by incipient wetness impregnation and characterized by a series of characterization methods. Competitive adsorption desulfurization performance was evaluated in a fixed-bed flow reactor.