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Complete and effective sulfur removal from liquid fuels is essential to meet the sulfur standard requirements. The oxidative desulfurization (ODS) process has been extensively used for the desulfurization of liquid fuels. In the current study, a comprehensive survey was conducted on the most important factors of ODS, including the types of catalysts, oxidizing agents, extraction solvents, liquid fuels, and process operating conditions. Various types of catalysts, nanocatalysts, magnetic catalysts, photocatalysts, electrocatalysts, biocatalysts, and emulsion catalytic systems have been studied in the ODS process. According to the obtained results, desulfurization catalysts were categorized into 11 groups, including metal oxides, metal complexes, metal free, titanosilicates, ionic liquids, polyoxometalates, metal−organic frameworks, porous aromatic frameworks, covalent organic frameworks, enzymes, and Fenton and Fenton-like catalysts. The advantages and drawbacks of the ODS catalysts were reviewed. The results indicate that the development of experimental design, modeling, and simulation in the ODS process helps to identify the most important variables, facilitate future research, and achieve maximum sulfur removal. Using technologies assisted with ODS such as ultrasound, cold plasma, microwave radiation, hydrodynamic cavitation, photo/light, electrochemistry, magnetic field, and biotechnology can improve sulfur removal and reduce reaction time.

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Background:In the last decades, mesoporous silica nanoparticles (MSNs) are improved for drug delivery, imaging, and biomedical applications due to their special properties such as large surface area, high drug loading capacity, tunable pore size, and modification of surface area by functional groups. Objectives: The aim of this study was to evaluate MSNs as carriers for oral colon-specific and human plasma blood delivery of vitamin C. Materials and Methods: In this work, mesoporous silica nanoparticles were synthesized and characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and N2-adsorption. Then MSNs were loaded by L-ascorbic acid (AscH 2), and the release of L-ascorbic acid from AscH 2-MSNs into the simulated fluids in different pHs was investigated, including simulated gastric fluid (SGF, pH, 1.2), simulated intestinal fluid (SIF, pH, 6.8), and simulated body fluid (SBF, pH, 7.4). The amount of loaded AscH 2 into the MSNs was determined by thermal gravimetric analysis (TGA). Results: Synthesized MSNs were spheres and the average diameter of them was 100 ± 9 nm. Results showed that about 567.8 nanomole of vitamin C . It was found that the burst release of AscH 2 into SGF was slower than SIF and SBF. Conclusions: The rate of AscH 2 release from the nanoparticles into alkaline solutions was faster than acidic solutions because of electrostatic interactions between vitamin C and MSNs surface. The loading amount of Vitamin C was dependent on the surface of chemical moiety of MSNs and the steric effects of vitamin C structure.

In this study, mesoporous silica nanoparticles (MSN) with different pore diameters were used for encapsulation of gallic acid (GA). All nanoparticles were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, N 2 adsorption isotherms, scanning electron microscopy, X-ray diffraction, and z-potential analysis for determination of their characterizations. The effects of different pore sizes of nanoparticles on loading of GA and its release from GA-loaded nanoparticles into simulated gastric fluid (SGF, pH 1.2), simulated intestinal and colon fluids (SIF and SCF, pHs 6.8 and 7.4, respectively), simulated body fluid (SBF, pH 7.4), and simulated gastrointestinal tract fluid (SGITF) were investigated. The pore size increased with the increase of mixing time of mesitylene as a swelling agent. GA is an unstable molecule that decomposes in alkaline pH. The imidazole buffer is the best for investigation of GA release into the alkaline media. The increase of nanoparticles pore size made the enhancement of GA loading. The released GA from GA-loaded nanoparticles into SGF was slower than that into SIF and SBF. Release of GA was strongly pH dependent on the selected media. The antioxidant activity, based on the 1,1-diphenyl-2-picrylhydrazyl assay, of released GA into SGITF and SBF was conserved and correlated strongly with its content in the selected media.