Sulfur Adsorption Capacity Research Articles

Preparation of Ni/ZnCo2O4@ZnO composite metal oxide adsorbent and its adsorption desulfurization and regeneration performance

Preparation of Ni/ZnCo2O4@ZnO composite metal oxide adsorbent and its adsorption desulfurization and regeneration performance

H2S adsorbed by bismuth oxychloride under room temperature

H2S adsorbed by bismuth oxychloride under room temperature

3D printing of hierarchically porous lightweight activated carbon/alumina monolithic adsorbent for adsorptive desulfurization of hydrogenated diesel

3D printing of hierarchically porous lightweight activated carbon/alumina monolithic adsorbent for adsorptive desulfurization of hydrogenated diesel

Deep Desulfurization of Diesel Fuel by Guard Bed Adsorption of Activated Carbon and Locally Prepared Cu-Y Zeolite

Desulfurization of a simulated diesel fuel by different adsorbents was studied in a fixed-bed adsorption process operated at ambient temperature and pressure. Three different adsorption beds were used, commercial activated carbon, Cu-Y zeolite, and layered bed of 15wt% activated carbon followed by Cu-Y zeolite.Initially Y-zeolite was prepared from Iraqi rice husk and then impregnated with copper. In general, the adsorbents tested for total sulfur adsorption capacity at break through followed the order Ac/Cu-Y zeolite>Cu-Y zeolite>Ac. The best adsorbent, Ac/Cu-Y zeolite is capable of producing more than 30 cm3 of simulated diesel fuel per gram of adsorbent with a weighted average content of 5 ppm-S, while Cu-Y zeolite producing of about 20 cm3 of diesel fuel per gram of adsorbent with a weighted average content of 2ppm-S. Activated carbon breaks through almost immediately.

A Novel Pd Precursor Loaded γ‐Al2O3 with Excellent Adsorbent Performance for Ultra‐Deep Adsorptive Desulfurization of Benzene

AbstractFabricating highly water‐soluble and chlorine‐free precursors from Pd complexes remains challenging. Here, a novel Pd precursor (ammonium dinitrooxalato palladium(II) ((NH4)2[Pd(NO2)2(C2O4)]·2H2O)) is synthesized to address this challenge. Additionally, a Pd/Al2O3 adsorbent is prepared using γ‐Al2O3 as a base material to host Pd. The ligand action of the Pd complex forms single Pd atoms and Pd sub‐nano clusters on the surface of γ‐Al2O3. Pd/Al2O3‐4 as an adsorbent is evaluated using the benzene ultra‐deep desulfurization procedure, wherein thiophene is used as a probe molecule. The sulfur adsorption capacity of Pd/Al2O3‐4 is 1.76 mg g−1 for the ultra‐deep adsorptive desulfurization of benzene at a sulfur concentration of 50 ppm. The sulfur adsorption capacity of the new Pd/Al2O3‐4 adsorbent is 21.8% higher than that of a commercial Pd/Al2O3 adsorbent. In addition, the stability and durability of Pd/Al2O3‐4 are investigated at a sulfur concentration of 1 ppm. The Pd/Al2O3‐4 adsorbent achieves ≈100% thiophene removal after 434 h, which is 62 h more than the time required by the commercial Pd/Al2O3 adsorbent. The novel Pd precursor shows excellent potential for industrial applications, and the Pd/Al2O3‐4 adsorbent can be produced on a mass scale of 500 kg per batch.

Hydrogen sulfide removal from simulated synthesis gas using a hot gas cleaning system

This study investigated the removal, adsorption, and regeneration performances of simulated H2S produced from rice straw gasification in a hot gas cleaning system with combination of three types of adsorbents including zeolite, calcined dolomite and activated carbon. These experiments were conducted at 250 ℃ hot gas cleaning system and simulated synthesis gas containing hydrogen sulfide (H2S) concentration at 200 ppm. The experimental results indicated that the tested H2S removal efficiency and adsorbed capacity were observed to be adsorbed in decreasing order: activated carbon > calcined dolomite > zeolite. The adsorption capacities of zeolite, calcined dolomite, and activated carbon are 2.22, 3.16, 5.88 mg S/g adsorbents, respectively. In this research, the calcined dolomite shows poor adsorption-regeneration ability due to its deactivation by H2S. However, the tested zeolite and activated carbon could be fully regenerated at 350 °C with a stable sulfur adsorption capacity during four adsorption-regeneration cycles. These results gained from this study could significantly support researchers obtaining more information about the synthesis gas contaminants removal during hot gas temperature operation process.

Competitive Adsorption in a Multicomponent Diesel System Using Nickel Oxide/Activated Carbon

Nickel oxide, which acts as an intermediate Lewis acid, was loaded onto activated carbon (AC) to enhance the adsorption selectivity of AC in the desulfurization of model diesel. The total sulfur adsorption capacity increased from 2.46 to 4.42 mg-S·g adsorbent–1 and the total sulfur removal increased from 46.8 to 84.5% using the AC and Ni(10%)O/AC adsorbents, respectively. Multicomponent isothermal modeling showed that the incorporation of NiO onto AC significantly improved the synergistic interactions between the thiophenic compounds while mitigating competitive interactions between the more steric 4,6-dimethyl dibenzothiophene (4,6-DMDBT) and 4-methyl-dibenzothiophene (4-MDBT) compounds. The mitigation was attributed to new adsorbate-specific sites created by loading NiO on AC. Spent adsorbent characterization and pyridine adsorption-IR analysis suggested that higher desulfurization performance of the Ni(10%)O/AC adsorbent was attributed to an increase in the adsorbent’s Lewis acidity upon loading with NiO, leading to increased Ni–S acid–base interactions, in addition to π-complexation.

Conductive few-layered 1T-MoSe2/MXene as a highly-efficient catalyst for accelerating bidirectional sulfur redox kinetics in Li-S batteries

Conductive few-layered 1T-MoSe2/MXene as a highly-efficient catalyst for accelerating bidirectional sulfur redox kinetics in Li-S batteries

Acidic sites enhanced ultra-deep desulfurization performance of novel NiZnO-based mixed oxides mesoporous adsorbents

Acidic sites enhanced ultra-deep desulfurization performance of novel NiZnO-based mixed oxides mesoporous adsorbents

Defect engineering and post-synthetic reduction of Cu based metal–organic frameworks towards efficient adsorption desulfurization

• ADS performance of the best CuBDC-x is 104.5% higher than the original CuBDC. • Both the defects and porosity can be regulated by a defect engineering method. • A convenient ethanol thermal treatment is developed to reduce Cu 2+ to Cu + . • Cu + rather than Cu 2+ are demonstrated to be the adsorption site of mercaptan. Adsorption desulfurization (ADS) is one of the most potential technologies for desulfurization of gasoline, while developing adsorbents with high sulfur capture capability to meet the strict environmental regulations remains a challenge. Here, a series of CuBDC-x adsorbents containing additional defects and enhanced adsorption sites via modulator-induced defect engineering and subsequent post-synthetic reduction strategy were synthesized. The optimal CuBDC-1 samples showed a remarkable sulfur adsorption capacity of 41.1 mg S/g in model fuel, which is 104.5% higher than that of original CuBDC. The Cu + rather than Cu 2+ cations in MOFs were found to be the main adsorption sites for mercaptan molecules. This work offers a new insight into developing high-efficiency adsorbent for ultra-deep desulfurization.

Design and Performance of an Adsorption Bed with Activated Carbons for Biogas Purification.

Organic waste can be efficiently converted into energy using highly efficient energy systems, such as SOFCs coupled to the anaerobic digestion process. SOFC systems fed by biogenous fuels, such as biogas or syngas, suffer long-term stability due to trace compound impacts. It follows that, a mandatory gas cleaning section is needed to remove these pollutants at lower concentrations. This work investigates the adsorption mechanism for micro-contaminant removal through experimental results achieved using solid sorbents. Samples of different sorbent materials were analyzed in the laboratory to determine their performances in terms of sulfur (mainly hydrogen sulfide) and siloxanes (mainly D4-Octamethylcyclotetrasiloxane) adsorption capacities. The analysis shows that the chemical composition of the samples influences the adsorption of H2S (i.e., presence of calcium, iron, copper), while the effect of their textural properties mainly influences the adsorption of siloxane compounds, such as D4. A quantitative analysis was performed considering the influence of gas velocity on adsorption capacity. By increasing the biogas velocity (+45% and +89%), there was an indirect correlation with the H2S adsorption capacity (-27% and -44%). This identified an aspect related to the residence time required to be able to remove and retain the trace compound. The results obtained and summarized were used to develop a strategy for the removal of trace compounds in large-scale plants, e.g., for water purification.

Bimetallic-MOF-Derived ZnxCo3-xO4/Carbon Nanofiber Composited Sorbents for High-Temperature Coal Gas Desulfurization.

Desulfurization sorbent with a high active component utilization is of importance for the removal of H2S from coal gas at high temperatures. Thus, the hypothesis for producing ZnxCo3-xO4/carbon nanofiber sorbents via the combinations of electrospinning, in situ hydrothermal growth, and carbonization technique has been rationally constructed in this study. ZnxCo3-xO4 nanoparticles derived from metal-organic frameworks are uniformly loaded on the electrospun carbon nanofibers (CNFs) with high dispersion. ZnxCo3-xO4/CNFs sorbents possess the highest breakthrough sulfur adsorption capacity (12.4 g S/100 g sorbent) and an excellent utilization rate of the active component (83.2%). The excellent performance of ZnxCo3-xO4/CNFs can be attributed to the synergetic effect of the hierarchical structure and widely distributed ZnxCo3-xO4 on the CNFs supporter. The decomposition of Zn/Co-ZIFs not only generates the nucleus of oxides but also realizes their physical isolation through the formation of carbon grids on the surface of CNFs, avoiding the aggregation of oxides. Furthermore, ZnxCo3-xO4/CNFs sorbents show an overwhelming superiority over the ZnO/CNFs sorbent, which is attributed to the introduction of Co and then the promotion of the stability of Zn at high temperatures. The presence of Co also accelerates the adsorption of H2S on the active site of the oxide surface. The presented method is beneficial for promoting desulfurization performances and producing sorbents with high utilization of active components.

Facile fabrication of La3+ sites in confined spaces for adsorptive desulfurization

La 2 O 3 -modified materials are attractive for adsorptive desulfurization of fuels because of non-toxicity, excellent desulfurization efficiency, and reasonable cost. Nevertheless, the desulfurization activity of such materials strongly relies on the size of La 2 O 3 active sites. Herein, we designed a facile grinding strategy to functionalize KIT-6 with La 2 O 3 for the first time by taking advantage of confined spaces and silanols. The La(NO 3 ) 3 precursor was inserted directly to the nanoconfinements sandwiched between silica walls and template in template-containing mesoporous KIT-6. Subsequent calcination not only decomposing La(NO 3 ) 3 to La 2 O 3 but also remove template and avoid multiple calcination required in traditional strategies. This leads to the dispersion of La 2 O 3 up to 20 wt%, 20LaAK-6, with smaller size making La 2 O 3 -containing adsorbent highly efficient for desulfurization of model fuel and the sulfur adsorption capacity can reach to 0.2 mmol./g, which is obviously higher than that on 20LaCK-6 (0.14 mmol./g) derived from template-free KIT-6 as well as that on other La 2 O 3 -based materials reported previously. Furthermore, 20LaAK-6 exhibited outstanding stability and regeneration ability making it attractive to be applied as potential candidate for deep desulfurization of fuels. Development of (A) larger La 3+ oxide with via traditional strategy and (B) well dispersed La 3+ NPs by taking confined spaces of AK. • Facile and advanced dispersion of La 2 O 3 over as-prepared KIT-6 via solid grinding strategy. • P123-occluded KIT-6 regulate size and dispersion of La 2 O 3 better than P123-free KIT-6. • Silanols (Si-OH) and confined spaces of as-synthesized KIT-6 are crucial for La 2 O 3 dispersion. • Silanols and template P123 enhanced the interaction of La 2 O 3 with as-synthesized KIT-6. • Grinding strategy is time and energy efficient and La 2 O 3 /KIT-6 is attractive for ADS of fuels.

Enhanced shape-selective-desulfurization performance of CuY@silicalite-1 core-shell composites with highly dispersed Cu2+ active adsorption sites

An improved CuY@silicalite-1 core-shell composite was developed with a higher shape-selective adsorption desulfurization performance of DMDS from MTBE solution (88.5 mg s /g adsorbents ). By isolating the bidirectional chemical environments via a resin interlayer between Y zeolite and silicalite-1 shell, ethylenediamine modification (NH 2 -(CH 2 ) 2 -NH 2 , EDA) was further applied after alkali treatment as a connecting bridge between Cu 2+ and Y zeolite. During which, one of the -NH 2 terminal groups of EDA could bind to Si-OH and the other -NH 2 could complex with Cu 2+ . The results showed that alkali treatment for 2 h, Y: EDA= 1: 0.1, Cu 2+ concentration of 0.05 mol/L, EDA and Cu 2+ infiltration for 8 times could maximize the sulfur adsorption capacity of the synthesized core-shell composite. And in addition to an excellent sulfur adsorption activity according to adsorption kinetics and isotherms analysis, CSR-CuY OH (0.1–0.05–8) also presented good stability even after 6 cycles of regeneration. • Alkali is used to tune the structure of Y zeolite. • EDA is applied as a connecting bridge between Cu 2+ and Y zeolite for good dispersity. • Resin layer provides stable external environment for silicalite-1 shell. • Sulfur adsorption capacity of selective-adsorption achieves 88.5 mg s /g adsorbents .

Effective removal of hydrogen sulfide from landfill gases using a modified iron pentacarbonyl desulfurization agent and the desulfurization mechanism

High-efficiency desulfurization is key to the recovery and use of landfill gases. In this study, a nano‑iron oxide desulfurization agent modified from iron pentacarbonyl was prepared in n-decane (DE) and hexadecane (HE) by ultrasonic disruption without any supporting materials and its hydrogen sulfide removal ability and desulfurization mechanism were studied. The yield of the desulfurization agent was higher when HE was used as the solvent; however, the products generated by both solvents had the same crystal type and similar properties. The efficiency of the desulfurization agent was significantly improved at 150-200 °C, exceeding 90% at 150 °C with single sulfur production. The maximum sulfur adsorption capacity of the desulfurization agent produced after 3 h of DE ultrasonic treatment at 200 °C (DE3) was 492 mg/g (desulfurization efficiency = 97.33%), while that of the agent produced after 3 h of HE ultrasonic treatment at 250 °C (HE3) was 522 mg/g (desulfurization efficiency = 99.30%). The desulfurization reaction involved both chemical adsorption and catalytic decomposition and the catalytic decomposition reaction rate was lower than that of chemical adsorption. Therefore, the more FexSy produced in the chemical adsorption process, the better catalytic performance was.

Adsorptive desulfurization using period 4 transition metals oxide: A study of Lewis acid strength derived from the adsorbent ionic-covalent parameter

• The Lewis acidic strength of transition metals can be measured by Ionic-covalent parameter (ICP). • A novel concept using ICP to explain the trend removal of sulfur in diesel was developed. • No correlation was observed between Pearson hardness and sulfur removal. • A linear relationship was observed between the ICP and sulfur removal. • Adsorptive selectivity of sulfur compounds increased with the decrease in ICP. Pearson’s Hard and Soft Acids and Bases (HSAB) principle has been widely utilized in describing the adsorption trend of sulfur compounds when using transition metal/metal oxides as adsorbents. This study is the first to report on the use of the ionic covalent parameter (ICP) for explaining the adsorption trend of sulfur compounds. Period 4 transition metal oxides (Zn-oxide, Cr-oxide, Mn-oxide, Co-oxide, Fe-oxide, Cu-oxide, Ni-oxide), which act as intermediate Lewis acids, were incorporated into activated carbon (AC), and used in the adsorptive desulfurization (ADS) of model and commercial diesel samples. The study findings show that desulfurization activity in model diesel increased in proportion to the concentration of adsorbent Lewis acid sites. With commercial diesel, the loading of metal oxides significantly enhanced the sulfur adsorption capacity of AC and increased its selectivity for steric sulfur compounds. The results showed a poor correlation between sulfur removal and the Pearson hardness η th of the intermediate metal oxide cations. However, a strong inverse linear relationship was observed: sulfur removal decreased as the ICP th of the adsorbent metal oxide increased. The study findings suggest a novel concept, i.e. that the ICP is a more accurate measure of the Lewis acidic strength of transition metal oxides with varying crystal structures and metal geometries, and their subsequent desulfurization performance. Kinetic modelling showed that chemisorption was the controlling mechanism. The fixed-bed ADS of commercial diesel when using unmodified AC is best described by the Yoon-Nelson and Thomas models. Adsorption when using the Ni-oxide/AC adsorbent was correlated to the filtration advection–dispersion equation.

Controlling the bidirectional chemical environments for high-performance Y@silicalite-1 core-shell composites in shape selective desulfurization

• Alkali and Cu 2+ are used to tune the structure and increase active sites of Y zeolite. • Resin layer and EDA can provide stable external environment for silicalite-1 shell. • Selective-adsorption achieved 75.58 mg/g, double of 37.1 reported previously. • Extraction before calcination kept 92% desulfurization rate after 6 regeneration cycles. A high-performance Y@silicalite-1 core–shell composite for shape- selective adsorption desulfurization was synthesized by controlling the bidirectional chemical environments via a resin interlayer between Y zeolite core and silicalite-1 shell. In this process, the alkali treatment, Cu 2+ ion-exchange, Cu 2+ equal volume impregnation, resin coating and ethylenediamine modification were applied to work collaboratively for a high shape selectivity and high sulfur adsorption capacity. Results showed that alkali treatment for 2 h, TEOS:Y = 4, Y:3-aminophenol = 1:1, Y: EDA = 1:1 and 550 °C calcination could endow the synthesized core–shell structured composite with a high-performance in shape-selective adsorption desulfurization of DMDS from MTBE solution with a maximum sulfur adsorption capacity of 75.58 mg s /g adsorbents , which was more than double of the best DMDS sulfur adsorption capacity from MTBE (37.07 mg s /g adsorbents ) reported previously. The adsorption kinetic and isotherm analysis indicated that the adsorption of DMDS on Y zeolites was monolayer-chemisorption process, and the corresponding theoretical saturated adsorption capacity could reach up to 84.6 mg s /g adsorbents . The regeneration capability can be effectively improved by ethanol extraction before calcination, retaining a high desulfurization rate level at more than 92% even after 6 cycles.

Preparation and characterization of zinc oxide nanoparticles incorporated tragacanth nanofibers for adsorbing fuel sulfur compounds

AbstractThis study concerns the electrospinning of tragacanth nanofibers containing zinc oxide nanoparticles with the aim of separating sulfur compounds from crude oil. Zinc oxide incorporated tragacanth nanofibers were electrospun from tragacanth solutions containing zinc oxide nanoparticles with concentrations of 5, 10, 15, and 20 (% w/w). The average diameter of these nanofibers were 91.6, 94.1, 95.4, and 97.8 nm, respectively. SEM images showed that zinc oxide nanoparticles incorporated tragacanth nanofibers were uniformly electrospun with no beads. FTIR analysis showed some interactions between zinc oxide nanoparticles and tragacanth macromolecules. XRD studies showed a two phase microstructure consisting of semi‐crystalline tragacanth matrix with zinc oxide crystallites dispersed in it. The highest filtration efficiency for 300 ml of Isfahan and Gachsaran crude oil was 75.3% and 62.2%, respectively. Moreover, the highest sulfur adsorption capacity obtained for Isfahan and Gachsaran crude oil was 211.20 mg g−1 and 108.19 mg g−1, respectively.

Tuning surface chemical property in hierarchical porous carbon via nitrogen and phosphorus doping for deep desulfurization

In this study, we successfully synthesized a N, P-doped porous carbon (NPCs) as novel adsorbents by pyrolyzing a mixture of triphenylphosphine, 1,10-phenanthroline compound and MgO template under an argon atmosphere. The NPCs adsorbent exhibited excellent adsorption activity with a high capacity of 63.32 mg S/g at room temperature, a high selectivity for dibenzothiophene (DBT) removal, and a 90% retention of initial performance after six cycles. In addition, density functional theory (DFT) calculations reveal that the N-P bonds of NPCs are more affinity to DBT. This study paves the way for the development of highly efficient heteroatomic doped porous carbon adsorbent. • N, P co-doped NPCs were synthesized by a pyrolysis method with MgO template. • Synthesized carbon shows high adsorption capacity and selectivity for DBT. • Ether hierarchical pore and N-P bond are the major adsorption determinants. • The adsorption process fit well with the pseudo-second order and Langmuir model. Rational elemental doping and structural construction of carbonaceous absorbents is an efficient technique for removal of sulfide from oil. In this line, a novel N, P co-doped porous carbon network (NPC) was reported for the first time to removal of dibenzothiophene (DBT). By adjusting the carbonization temperature, a series of hierarchical porous carbons with large specific surface area and high heteroatom content are obtained. As the absorbent, the optimal NPC presents a superior sulfur adsorption capacity of 63.32 mg/g, a 90% retention of initial performance after six cycles, and a excellent selectivity for DBT removal. The in-depth analysis indicates that the unique micro-mesoporous structure ensures the shape-selective adsorption and accelerates the transport of DBT. More importantly, a large number of formed N-P bonds act as the adsorption active sites to enhance the adsorption strength for DBT. Density functional theory (DFT) calculation reveals that the synergistic effect of N, P co-doped configurations greatly reduces the adsorption energy for DBT, indicating its significant affinity to DBT. In additioin, based on the kinetic and thermodynamic analysis, it is found that the DBT adsorption of NPCs fits into the pseudo second-order kinetic and Langmuir models, revealing the spontaneous adsorption at room temperature. This present work offers a new strategy to synthesize the highly effecient adsorbent for adsorption desulfurizatioin.

Preparation and characteristics of CuO/γ-Al2O3 nanocomposite as efficient adsorbent for adsorption of sulfur compounds from Iraqi naphtha

Herein, CuO/γ-Al 2 O 3 nanocomposite adsorbent were synthesized and characterized for adsorptive desulfurization of naphtha fraction. The γ-Al 2 O 3 nanoparticles was first, prepared by coprecipitation route and characterized by XRD, AFM, BET and SEM methods. Then, CuO was supported onto γ-Al 2 O 3 nanoparticles by impregnation method. The effects of different parameters were studied on the sulfur removal efficiency and adsorption capacity in batch and continuous modes. These parameters included contact time and adsorbent dose in batch study, while in continuous study; the breakthrough curves were generated in fixed bed adsorber. The batch adsorption study indicates that the CuO/γ-Al 2 O 3 nanoadsorbent exhibited better max adsorption capacity (78.8 mg/g) than bare γ-Al 2 O 3 (34.2 mg/g). Different adsorption kinetics models and isotherms were investigated for CuO/γ-Al 2 O 3 and γ-Al 2 O 3 nanoadsorbents. The adsorption kinetics of naphtha desulfurization were closely followed the second order kinetic model. Also, Langmuir isotherm was well represented the equilibrium adsorption of sulfur. In continuous study, breakthrough curves were generated for CuO/γ-Al 2 O 3 nanocomposite at LHSV = 2 h −1 and bed height = 7 cm. The time of breakthrough point was 320 min. Moreover, the Yoon–Nelson model fitted best for the continuous experimental data.