A novel MOF-808 derived material for oxidative desulfurization: the synergistic effect of hydrophobicity and electron transfer

A functionalized modified metal-organic framework material, T-MOF-808, was synthesized through hydrophobic modification with tetraethyl orthosilicate (TEOS) and chlorotrimethylsilane (TMCS). Then a supported oxidative desulfurization catalyst, [C12Py]3(NH4)3Mo7O24/T-MOF-808(s), was prepared by using a heteropoly acid ionic liquid as the active component. The prepared samples were characterized using FT-IR, XRD, SEM, TEM, XPS, etc. [C12Py]3(NH4)3Mo7O24/T-MOF-808(s) was used in the oxidative desulfurization of dibenzothiophene (DBT). At the same time, the effects of different loadings of the active component, oxygen sulfur ratios, reaction temperatures, and reaction time were also investigated. [C12Py]3(NH4)3Mo7O24/T-MOF-808-15%(s) could oxidize 100% of DBT in 40 min at 60 °C. Significantly, the catalyst exhibited no discernible decline in catalytic activity after 14 runs. In addition, the efficiency of sulfur removal was 85.76% in actual diesel oil. It was found that the cooperative impact of hydrophobic modification and electron transfer makes an important contribution to the high activity. The hydrophobic modification provides a novel approach for using MOF materials in the oxidative desulfurization process.

Oxidative Desulfurization of Real High-Sulfur Diesel Using Dicarboxylic Acid/H2O2 System

From the perspective of pollution, economics, and product quality, it is very important to find an efficient way to minimize the sulfur content of petroleum products such as gasoline and diesel. In this work, an effective, inexpensive, and simple oxidative desulfurization system based on hydrogen peroxide activation by three dicarboxylic acids which have different carbon numbers (i.e., malonic acid, succinic acid, and glutaric acid) was utilized for the desulfurization of a real diesel sample with high organic sulfur-containing compounds. The desulfurization process was based on the oxidation of sulfur compounds in diesel fuel to the corresponding sulfones followed by acetonitrile extraction of the sulfones. To select the optimal experimental conditions, the effects of several parameters, including temperature, catalyst H2O2 dosages, and treatment time, were investigated. The results showed that the developed system was effective in desulfurizing real diesel fuel with high sulfur content. With an initial total sulfur content of about 8104 mg/L, the desulfurization rate from the diesel sample reached more than 90.9, 88.9, and 93%, using malonic acid, succinic acid, and glutaric acid, respectively. The optimum parameters such as reaction temperature, reaction time, H2O2 (50 w/w%), and carboxylic acid dosage for oxidative desulfurization were determined to be 95 °C, 6 h, 10 mL, and 0.6 g, respectively. The conversion of refractory sulfur compounds into extractable sulfone forms was verified using gas chromatography. Moreover, the kinetic study confirmed that the designed reaction system follows the pseudo-first-order kinetic model.

Multifaceted potential applicability of hydrotalcite-type anionic clays from green chemistry to environmental sustainability

Hydrotalcite-like anionic clays (HTs) also known as Layered double hydroxides (LDHs) have been developed as multifunctional materials in numerous applications related to catalysis, adsorption, and ion-exchange processes. These materials constitute an important class of ionic lamellar solid clays of Brucite-like structure which comprise of consecutive layers of divalent and trivalent metal cations with charge balancing anions and water molecules in interlayer space. These materials have received increasing attention in research due to their interesting properties namely layered structure, ease of preparation, flexible tunability, ability to intercalate different types of anions, electronic properties, high thermal stability, high biocompatibility, and easy biodegradation. Moreover, HTs/LDHs have unique tailorable and tuneable characteristics such as both acidic and basic sites, anion exchange capability, surface area, basal spacing, memory effect, and also exhibit high exchange capacities, which makes them versatile materials for a wide range of applications and extended their horizons to diverse areas of science and technology. This study enlightens the various rational researches related to the synthetic methods and features focusing on synthesis and/or fabrication with other hybrids and their applications. The diverse applications (namely catalyst, adsorbent to toxic chemicals, agrochemicals management, non-toxic flame retardants, and recycling of plastics) of these multifunctional materials related to a clean and sustainable environment were also summarized.

Hexaconazole-Micelle Nanodelivery System Prepared Using Different Surfactants for Ganoderma Antifungal Application

Reports on fungicide-based agronanochemicals in combating disastrous basal stem rot disease in the oil palm industry are scant. Herein, we describe the potential of fungicide nanodelivery agents based on hexaconazole-micelle systems produced using three different surfactants; sodium dodecylbenze sulfonate (SDBS), sodium dodecyl sulfate (SDS) and Tween 80 (T80). The resulting nanodelivery systems were characterized and the results supported the encapsulation of the fungicide into the micelles of the surfactants. We have investigated in detail the size-dependent effects of the as-synthesized micelles towards the inhibition growth of Ganoderma Boninense fungi. All the nanodelivery systems indicate that their size decreased as the surfactant concentration was increased, and it directly affects the fungal inhibition. It was also found that Tween 80, a non-ionic surfactant gave the lowest effective concentration, the EC₅₀ value of 2, on the pathogenic fungus Ganoderma boninense compared to the other anionic surfactants; SDBS and SDS. This study opens up a new generation of agronanofungicide of better efficacy for Ganoderma disease treatment.

Oxidative Desulfurization Catalyzed by Phosphotungstic Acid Supported on Hierarchical Porous Carbons

A hierarchical porous carbon material (HPC) with an ultra-high specific surface area was synthesized with sisal fiber (SF) as a precursor, and then H3PW12O40·24H2O (HPW) was immobilized on the support of SF-HPC by a simple impregnation method. A series characterization technology approved that the obtained SF-HPC had a high surface area of 3152.46 m2g-1 with micropores and macropores. HPW was well-dispersed on the surface of the SF-HPC support, which reduced the loading of HPW to as low as 5%. HPW/SF-HPW showed excellent catalytic performance for oxidative desulfurization, and the desulfurization rate reached almost 100% under the optimal reaction conditions. The desulfurization rate of HPW/SF-HPW could be maintained at above 94% after four recycles.

Vanadium-substituted heteropolyacids (H3+mPW12−mVmO40) encapsulated in Fe3O4@UiO-66 magnetic core–shell microspheres as excellent catalysts for oxidative desulfurization under oxygen

In this study, the novel magnetic core–shell composites Fe₃O₄@UiO-66-HPA, consisting of magnetic Fe₃O₄@UiO-66 and vanadium-substituted Keggin-type heteropolyacid active species supported by Zr-MOF, were prepared via a one-pot method and fully characterized.

Polyoxometalates encapsulated into hollow double-shelled nanospheres as amphiphilic nanoreactors for an effective oxidative desulfurization

Although some catalytic hollow nanoreactors have been fabricated in the past, the encapsulated active species focus on metal nanoparticles, and a method for polyoxometalate (POM)-containing hollow nanoreactors has seldom been developed. Herein, we report a synthetic strategy towards POM-based amphiphilic nanoreactors, where the hollow mesoporous double-shelled SiO₂@C nanospheres were used to encapsulate Keggin-type H₃PMo₁₂O₄₀ (PMo₁₂). The outer hydrophobic carbon shell was beneficial for the enrichment of the organic substrate around the nanoreactor and simultaneously prevented the deposition of POMs on the outer surface of the nanoreactor. The inner hydrophilic silica cavity was modified by two types of organosilanes, which not only created an amphiphilic cavity environment but also acted as an anchor to mobilize PMo₁₂. As the POM nanoreactor had the hydrophilic@hydrophobic SiO₂@C shell and an amphiphilic cavity, both dibenzothiophene (DBT) and H₂O₂ could smoothly diffuse into the nanosized cavity, where the DBT was effectively oxidized (conversion: >99%) by the immobilized PMo₁₂ under mild conditions. Importantly, the control experiments indicated that the confined effect of nanoreactor, amphiphilic SiO₂@C double-shell, unique cavity environment, and mesoporous channels accounted for an excellent catalytic performance. Moreover, the nanoreactor was robust and could be reused for five cycles without loss of activity.

SILCs in oxidative desulfurization: effect of support and heteropolyanion

Catalysts for oxidative desulfurization based on imidazolium ionic liquid and H₃PMo₁₂O₄₀ or H₃PW₁₂O₄₀, grafted to mesoporous silicas.

Synergistic effects of MOF-76 on layered double hydroxides with superior activity for extractive catalytic oxidative desulfurization

The combination of MOF-76 with an LDH provides a completely new route for the synthesis of MOF–LDH advanced functional materials.

Solvent-Mediated and Mechanochemical Methods for Anion Exchange of Carbonate from Layered Double Hydroxides Using Ammonium Salts

Deintercalation of carbonate from layered double hydroxides (LDH) followed by intercalation of another anion (decarbonative intercalation) is a good method for the synthesis of crystalline LDH with different intercalated anions. We have carried out decarbonative intercalation of halides, nitrate, acetate, and sulfate by refluxing the carbonate-LDH with the corresponding ammonium salt in 1-butanol to obtain ordered LDH incorporating the desired anion. The crystallinity of the precursor LDH is retained in the anion-exchanged products, making this reaction a useful tool to prepare ordered LDH containing various anions. In addition, the morphology of the LDH is also retained after the exchange, making the reaction morphotactic. As the reaction is facilitated by the weak acidity of the ammonium salt, just grinding the carbonate-LDH with the ammonium salt of the desired anion also results in anion exchange. However, while the crystallinity of the LDH is retained, the morphology changes possibly due to breaking up of the crystals during the reaction.

Study on the performance and mechanism of aerobic oxidative desulfurization based on a dual-functional material possessing catalytic and adsorptive properties

Herein, three polyoxometalates, namely K₃PW₁₂O₄₀·10H₂O, K₆[α-P₂W₁₈O₆₂]·14H₂O, and K₈H[P₂W₁₅V₃O₆₂]·9H₂O, were successfully prepared and used in the air/n-octanaloxidative desulfurization (ODS) system.