Synthesis of the well-ordered hexagonal mesoporous silicate incorporated with phosphotungstic acid through a novel method and its catalytic performance on the oxidative desulfurization reaction

Recent Progress on Functionalized Nanoporous Heteropoly Acids: From Synthesis to Applications

Functionalized nanoporous heteropoly acids (HPAs) have garnered significant attention in recent years due to their enhanced surface area and porosity, as well as their potential for low-cost regeneration compared to bulk materials. This review aims to provide an overview of the recent advancements in the synthesis and applications of functionalized HPAs. We begin by introducing the fundamental properties of HPAs and their unique structure, followed by a comprehensive overview of the various approaches employed for the synthesis of functionalized HPAs, including salts, anchoring onto supports, and implementing mesoporous silica sieves. The potential applications of functionalized HPAs in various fields are also discussed, highlighting their boosted performance in a wide range of applications. Finally, we address the current challenges and present future prospects in the development of functionalized HPAs, particularly in the context of mesoporous HPAs. This review aims to provide a comprehensive summary of the recent progress in the field, highlighting the significant advancements made in the synthesis and applications of functionalized HPAs.

Confining Polyoxometalate Clusters into Porous Aromatic Framework Materials for Catalytic Desulfurization of Dibenzothiophene

Removal of notorious sulfur compounds to produce low-sulfur-content (≤10 ppm) diesel is necessary and vital for modern industry and environmental protection. A new type of inorganic-organic hybrid material has been designed and synthesized via confining molybdenum-containing polyoxometalate (POM) clusters within porous aromatic framework-1 (PAF-1) cavities named POM-PAF-1. Deep oxidative desulfurization experiments reveal that POM-PAF-1 possesses excellent reactivity under mild conditions, exemplified by a sulfur removal degree of 98.5% dibenzothiophene within 30 min at 30 °C. The improvement in oxidative desulfurization reactivity from traditional porous POM-based catalysts is owing to uniform POMs and lipophilic and porous PAF-1. The high performance of POM-PAF-1 in terms of excellent reactivity and good stability means it has potential in new heterogeneous catalysis.

An ultrasound enhanced catalytic ozonation process for the ultra-deep desulfurization of diesel oil

An ultrasound enhanced catalytic ozonation process was applied for the desulfurization of diesel oil with some metal salts of Keggin-type heteropolyacids, H₃PW₁₂O₄₀–M_x/nH_3−xPW₁₂O₄₀ (abbreviated as M_x/nH_3−xPW₁₂O₄₀), as catalysts.

An overview of conventional and alternative technologies for the production of ultra-low-sulfur fuels

Environmental concerns have given a great deal of attention for the production of ultra-low-sulfur fuels. The conventional hydrodesulfurization (HDS) process has high operating cost and also encounters difficulty in removing sulfur compound with steric hindrance. Consequently, various research efforts have been made to overcome the limitation of conventional HDS process and exploring the alternative technologies for deep desulfurization. The alternative processes being explored for the production of ultra-low-sulfur content fuel are adsorptive desulfurization (ADS), biodesulfurization (BDS), oxidative desulfurization (ODS), and extractive desulfurization (EDS). The present article provided the comprehensive information on the basic principle, reaction mechanism, workability, advantages, and disadvantages of conventional and alternative technologies. This review article aims to provide valuable insight into the recent advances made in conventional HDS process and alternative techniques. For deep desulfurization of liquid fuels, integration of conventional HDS with an alternative technique is also proposed.

A Simple Approach To Develop Tailored Mesoporosity in Nanostructured Heteropolysalts

In this study, we describe a very simple approach to the development of tailored mesoporosity in any nanostructured heteropolysalt with control over both the mesoporous volume and the pore size. This approach, which consists in the treatment of a solid microporous precursor with a basic agent, has been tested on the ammonium salt of the Keggin-type [PMo₁₂ O₄₀ ]^3- heteropolyanion and constitutes a novel procedure for the preparation of mesoporous solids with no precedents. The results obtained in this study allow two main conclusions to be drawn: 1) the micro- and mesoporous structures in the heteropolysalt nanoparticles are independent from each other and 2) the development of mesoporosity in the solid material must be related to a process of alkaline degradation within the core of the nanocrystals that aggregate into the particles. These results afford valuable additional information to the present model of porosity that has been established for heteropolysalts.

Necessity of calcination in the preparation of phosphotungstic acid@TiO2 composites. A case study on the facile sol–gel synthesis of nanospheres and their superior performance in catalytic oxi-desulfurization

Calcinated and un-calcinated PW₁₂@TiO₂ catalysts showed parallel performance in ECODS indicating the unnecessity of calcination in the preparation of PW₁₂@TiO₂.

Fabrication of calix[4]arene-attached mesoporous ammonium molybdophosphate–silica hybrid and its application as an adsorbent for cesium ions

The cesium cation is a common contaminant in medical and industrial products as well as in nuclear wastes, and it can present a serious risk to human health.

Extractive and oxidative desulfurization of model oil in polyethylene glycol

One-pot extractive and oxidative desulfurization of model oil in polyethylene glycol.

One-pot synthesis and characterization of tungsten-containing meso-ceria with enhanced heterogenous oxidative desulfurization in fuels

The sulfide was absorbed by the mesoporous ceria, and then oxidized to its corresponding sulfone by the active peroxo species.

A multicomponent assembly approach for the design of deep desulfurization heterogeneous catalysts

An assembly approach has been employed for the preparation of a multi-component heterogeneous catalyst showing high efficiency in deep desulfurization processes.

Synthesis of ordered meso/macroporous H3PW12O40/SiO2 and its catalytic performance in oxidative desulfurization

Ordered meso/macroporous phosphotungstic acid/SiO₂ (m/M-HPW/SiO₂) was first fabricated via the dual-templating method and exhibited superior catalytic performance in oxidative desulfurization.

An organic–inorganic hybrid based on an Anderson-type polyoxometalate immobilized on PVA as a reusable and efficient nanocatalyst for oxidative desulphurization of gasoline

An organic–inorganic hybrid based on Anderson-type polyoxometalate was synthesized and immobilized on PVA via sol–gel method and characterized by FT-IR, XRD, SEM and UV-vis spectroscopy. Its catalytic activity was tested on ODS of gasoline.

TiO2 microspheres supported polyoxometalate-based ionic liquids induced catalytic oxidative deep-desulfurization

A series of TiO₂ microspheres supported [SiW₁₂O₄₀]⁴⁻-based ionic liquids were successfully prepared and used as catalysts in oxidative desulfurization system. DBT was oxidized to DBT sulfone (DBTO₂) efficiently with the help of the catalyst and H₂O₂.

Fabrication of dual-mesoporous silica by triblock copolymers and metal-based ionic liquid: efficient and durable catalyst for oxidative desulfurization in fuel

The D-MoO₃–SiO₂ material with two uniform sets of mesopores exhibited a very high efficiency and excellent stability in the oxidative desulfurization of model oil.

One-pot synthesis of ordered mesoporous silica encapsulated polyoxometalate-based ionic liquids induced efficient desulfurization of organosulfur in fuel

Reaction procedure of desulfurization system.

Application of a H4SiMo12O40@SiO2 catalyst with a hollow core–shell structure to oxidative desulfurization

Designing a catalyst with excellent recyclability to improve oxidative desulfurization continues to challenge many researchers.

Synthesis of SBA-15 encapsulated ammonium molybdophosphate using Qaidam natural clay and its use in cesium ion adsorption

The ordered hexagonal mesoporous silica (SBA-15) encapsulated ammonium molybdophosphate (AMP) was successfully synthesized using low-grade natural clay from Qaidam Basin as silica and aluminum source, through a one-pot synthesis method.

Novel catalyst by immobilizing a phosphotungstic acid on polymer brushes and its application in oxidative desulfurization

In the study, an HPW–PDMAEMA–SiO₂ (phosphotungstic acid (HPW); poly-N,N-dimethylaminoethyl methacrylate (PDMAEAM)) catalyst was successfully synthesized.

Oxidative desulfurization of benzothiophene and thiophene with WOx/ZrO2 catalysts: effect of calcination temperature of catalysts

Oxidative desulfurization (ODS) of model fuel containing benzothiophene (BT) or thiophene (Th) has been carried out with WO(x)/ZrO2 catalyst, which was calcined at various temperatures. Based on the conversion of BT in the model fuel, it can be shown that the optimum calcination temperature of WOx/ZrO2 catalyst is around 700 °C. The most active catalyst is composed of tetragonal zirconia (ZrO2) with well dispersed polyoxotungstate species and it is necessary to minimize the contents of the crystalline WO3 and monoclinic ZrO2 for a high BT conversion. The oxidation rate was interpreted with the first-order kinetics, and it demonstrated the importance of electron density since the kinetic constant for BT was higher than that for Th even though the BT is larger than Th in size. A WOx/ZrO2 catalyst, treated suitably, can be used as a reusable active catalyst in the ODS.