Mesoporous Silicate Research Articles

Nanoparticles and Their Antibacterial Application in Endodontics.

Root canal treatment represents a significant challenge as current cleaning and disinfection methodologies fail to remove persistent bacterial biofilms within the intricate anatomical structures. Recently, the field of nanotechnology has emerged as a promising frontier with numerous biomedical applications. Among the most notable contributions of nanotechnology are nanoparticles, which possess antimicrobial, antifungal, and antiviral properties. Nanoparticles cause the destructuring of bacterial walls, increasing the permeability of the cell membrane, stimulating the generation of reactive oxygen species, and interrupting the replication of deoxyribonucleic acid through the controlled release of ions. Thus, they could revolutionize endodontics, obtaining superior results and guaranteeing a promising short- and long-term prognosis. Therefore, chitosan, silver, graphene, poly(lactic) co-glycolic acid, bioactive glass, mesoporous calcium silicate, hydroxyapatite, zirconia, glucose oxidase magnetic, copper, and zinc oxide nanoparticles in endodontic therapy have been investigated in the present review. The diversified antimicrobial mechanisms of action, the numerous applications, and the high degree of clinical safety could encourage the scientific community to adopt nanoparticles as potential drugs for the treatment of endodontic diseases, overcoming the limitations related to antibiotic resistance and eradication of the biofilm.

Pyroptosis Induction with Nanosonosensitizer-Augmented Sonodynamic Therapy Combined with PD-L1 Blockade Boosts Efficacy against Liver Cancer.

Induction of pyroptosis can promote anti-PD-L1 therapeutic efficacy due to the release of pro-inflammatory cytokines, but current approaches can cause off target toxicity. Herein, a phthalocyanine-conjugated mesoporous silicate nanoparticle (PMSN) is designed for amplifying sonodynamic therapy (SDT) to augment oxidative stress and induce robust pyroptosis in tumors. The sub-10nm diameter structure and c(RGDyC)-PEGylated modification enhance tumor targeting and renal clearance. The unique porous architecture of PMSN doubles ROS yield and enhances pyroptotic cell populations in tumors (25.0%) via a cavitation effect. PMSN-mediated SDT treatment efficiently reduces tumor mass and suppressed residual tumors in treated and distant sites by synergizing with PD-L1 blockade (85.93% and 77.09%, respectively). Furthermore, loading the chemotherapeutic, doxorubicin, into PMSN intensifies SDT-pyroptotic effects and increased efficacy. This is the first report of the use of SDT regimens to induce pyroptosis in liver cancer. This noninvasive and effective strategy has potential for clinical translation.

Manganese-Based Nanoparticle Vaccine for Combating Fatal Bacterial Pneumonia.

Bacterial pneumonia is the leading cause of death worldwide among all infectious diseases. However, currently available vaccines against fatal bacterial lung infections, e.g., pneumonic plague, are accompanied by limitations, including insufficient antigen-adjuvant co-delivery and inadequate immune stimulation. Therefore, there is an urgent requirement to develop next-generation vaccines to improve the interaction between antigen and adjuvant, as well as enhance the effects of immune stimulation. This study develops a novel amino-decorated mesoporous manganese silicate nanoparticle (AMMSN) loaded with rF1-V10 (rF1-V10@AMMSN) to prevent pneumonic plague. These results suggest that subcutaneous immunization with rF1-V10@AMMSN in a prime-boost strategy induces robust production of rF1-V10-specific IgG antibodies with a geometric mean titer of 315,844 at day 42 post-primary immunization, which confers complete protection to mice against 50 × LD50 of Yersinia pestis (Y. pestis) challenge via the aerosolized intratracheal route. Mechanistically, rF1-V10@AMMSN can be taken up by dendritic cells (DCs) and promote DCs maturation through activation of the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway and production of type I interferon. This process results in enhanced antigen presentation and promotes rF1-V10-mediated protection against Y. pestis infection. This manganese-based nanoparticle vaccine represents a valuable strategy for combating fatal bacterial pneumonia.

Impact of carrier hydrophilicity on solid self nano-emulsifying drug delivery system and self nano-emulsifying granule system

The purpose of this study was to investigate the impact of carrier hydrophilicity on solid self nano-emulsifying drug delivery system (SNEDDS) and self nano-emulsifying granule system (SEGS). The mesoporous calcium silicate (Ca-silicate) and hydroxypropyl-β-cyclodextrin (HP-β-CD) were utilised as hydrophobic carrier and hydrophilic carrier, respectively. The liquid SNEDDS formulation, composed of Tween80/Kollipohr EL/corn oil (35/50/15%) with 31% (w/w) dexibuprofen, was spray-dried and fluid-bed granulated together with Avicel using Ca-silicate or HP- β-CD as a solid carrier, producing four different solid SNEDDS and SEGS formulations. Unlike the Ca-silicate-based systems, spherical shape and aggregated particles were shown in HP-β-CD-based solid SNEDDS and SEGS, respectively. Molecular interaction was detected between Ca-silicate and the drug; though, none was shown between HP-β-CD and the drug. Each system prepared with either carrier gave no significant differences in micromeritic properties, crystallinity, droplet morphology, size, dissolution and oral bioavailability in rats. However, the HP-β-CD-based system more significantly improved the drug solubility than did the Ca-silicate-based system. Therefore, both carriers hardly affected the properties of both solid SNEDDS and SEGS; though, there were differences in the aspect of appearance, molecular interaction and solubility.

Lamellar mesoporous Mg-containing silicate adsorbents derived from iron ore tailings for high-efficient adsorption of mycotoxins and antibiotics

Iron ore tailing (IOT), as a typical solid waste, is in urgent need of high value-added utilization. The resource endowment and silicate composite characteristics owe IOT inherent potentials to prepare environmental functional materials. However, the Si-O-Si(M) bonds in IOT, having both ionic and covalent bonding properties, are very strong, which makes IOT difficult to efficiently utilize. Herein, sodium silicate, magnesium sulfate and potassium sodium tartrate (PST) were simultaneously introduced to promote the reconstitution of IOT as lamellar mesoporous Mg-containing silicate adsorbent. The adsorbents possess high specific area of 280.18 m2/g and abundant active sites, whose adsorption capacities for aflatoxin B1 (AFB1) and tetracycline hydrochloride (TC) were 30.05 mg/g, 217.39 mg/g, respectively. It is expected that the present work could lay a theoretical and experimental foundation for the high value-added functional utilization of IOT.

Transformation of Cu(OH)2 to mesostructural copper-silicate in alkaline silicate solution

Mesoporous materials with high surface area, tunable pore size, and large pore volume have applications in catalysis, adsorption, and optical devices. While the templating method has been used widely to synthesize these materials, removing the organic template leads to energy and chemical waste, and the emission of CO2 greenhouse gas. Here, a new non-organic templating method, based on structural transformation, is proposed to prepare mesostructural copper silicate with a high surface area (425 m2g-1) and large pore volume. This mesostructural transformation is already achieved by hydrothermally treating the Cu(OH)2 crystalline precipitate in an alkaline silicate aqueous solution. The copper silicate platelets obtained from a 5-day hydrothermal treatment in silicate solution have mesopores of about 3.5 nm. For the applications in absorption and catalyst application, the copper silicate has a high absorption efficiency (∼67%) and a fast removal rate toward PH3 gas at 600 ppb and a high-performance catalyst (yield of phenol derivatives about 86%) for the C–O coupling reaction. The mesostructural copper silicate platelets offer a cost-effective and environmentally friendly production method due to their flexible and straightforward preparation process. The synthetic route provides a promising approach to preparing different mesoporous metal silicates.

Efficient olefin epoxidation with high turnover rates over ordered mesoporous silica nanoparticles with uniform manganese sites

Olefin epoxidation has been studied over a series of mesoporous manganese silicate nanoparticles and tBuOOH. Partial substitution of Si by Mn in silica framework leads to highly dispersed, distorted Mn(III) sites, confirmed by various physicochemical analyses. High conversion and stable styrene oxide, stilbene oxide and epoxy cyclohexane yield have been achieved with MS75 with 1:1.5 ratio of olefin: oxidant. However, at faster reaction rates lower styrene oxide yield is observed at lower Mn-containing catalyst (MS100). High TON, TOF over manganese sites shows accessible monomeric Mn sites. Attributed to high reactant density at redox-active Mn silicate sites due to facile diffusion across shallow pore depth channels of nanoparticulate om-MSx and surface hydrophobic characteristics. The catalysts were found to be stable under recycling and filtration experiments. The excellent stability against leaching of active manganese species indicates stable sites and good textural properties in om-MSx, essential for extended activity.

Fischer–Tropsch Synthesis Catalysts for Selective Production of Diesel Fraction

The Fischer–Tropsch process is considered one of the most promising eco-friendly routes for obtaining synthetic motor fuels. Fischer–Tropsch synthesis is a heterogeneous catalytic process in which a synthesis gas (CO/H2) transforms into a mixture of aliphatic hydrocarbons, mainly linear alkanes. Recently, an important direction has been to increase the selectivity of the process for the diesel fraction. Diesel fuel synthesized via the Fischer–Tropsch method has a number of advantages over conventional fuel, including the high cetane number, the low content of aromatic, and the practically absent sulfur and nitrogen impurities. One of the possible ways to obtain a high yield of diesel fuel via the Fischer–Tropsch process is the development of selective catalysts. In this review, the latest achievements in the field of production of diesel via Fischer–Tropsch synthesis using catalysts are reviewed for the first time. Catalytic systems based on Al2O3 and mesoporous silicates, such as MCM-41, SBA-15, and micro- and mesoporous zeolites, are observed. Together with catalytic systems, the main factors that influence diesel fuel selectivity such as temperature, pressure, CO:H2 ratio, active metal particle size, and carrier pore size are highlighted. The motivation behind this work is due to the increasing need for alternative processes in diesel fuel production with a low sulfur content and better exploitation characteristics.

Green synthesis and characterization of silicate nanostructures coated with Pluronic F127/gelatin for triggered drug delivery in tumor microenvironments

Thermo-/pH-sensitive nanocomposites based on mesoporous silicate MCM-41 (MSNCs) derived from rice husk ash were synthesized and characterized. MSNCs were coated with thermo-/pH-sensitive Pluronic® F127 and gelatin to form MSNCs@gp nanocomposites, serving as carriers for controlled release of the anticancer drug doxorubicin (Dox). The in vitro and in vivo antitumor efficacy of MSNCs@gp-Dox against liver cancer was evaluated. Fourier-transform infrared (FTIR) spectra confirmed the silica nature of MSNCs@gp by detecting the Si-O-Si group. Under acidic microenvironments (pH 5.4) and 42 °C, MSNCs@gp-Dox exhibited significantly higher Dox release (47.33 %) compared to physiological conditions. Thermo-/pH-sensitive drug release (47.33 %) was observed in simulated tumor environments. The Makoid-Banakar model provided the best fit at pH 7.4 and 37 °C with a mean squared error of 0.4352, an Akaike Information Criterion of 15.00, and a regression coefficient of 0.9972. Cytotoxicity tests have demonstrated no significant toxicity in HepG2 cells treated with various concentrations of MSNCs@gp, while MSNCs@gp-Dox induced considerable cell apoptosis. In vivo studies in nude mice revealed effective suppression of liver cancer growth by MSNCs@gp-Dox, indicating high pharmaceutical efficacy. The investigated MSNCs@gp-based drug delivery system shows promise for liver cancer therapy, offering enhanced treatment efficiency with minimal side effects.

Ultrasound-Chargeable Persistent Luminescence Nanoparticles to Generate Self-Propelled Motion and Photothermal/NO Therapy for Synergistic Tumor Treatment.

Cancer phototherapy indicates advantages in ease of manipulation, negligible drug resistance, and spatiotemporal control but is confronted with challenges in tumor cell accessibility and intermittent light excitation. Herein, we propose a strategy with persistent luminescence (PL)-excited photothermal therapy (PTT), concurrent thermophoresis-propelled motion, and PL-triggered NO release, where PL emission is chargeable by ultrasonication for readily applicable to deep tumors. Mechanoluminescent (ML) nanodots of SrAl2O4:Eu2+ (SAOE) and PL nanodots of ZnGa2O4:Cr3+ (ZGC) were deposited on mesoporous silicates to obtain mSZ nanoparticles (NPs), followed by partially coating with polydopamine (PDA) caps and loading NO donors to prepare Janus mSZ@PDA-NO NPs. The ML emission bands of SAOE nanodots overlap with the excitation band of ZGC, and the persistent near-infrared (NIR) emission could be repeatedly activated by ultrasonication. The PL emission acts as an internal NIR source to produce a thermophoretic force and NO gas propellers to drive the motion of Janus NPs. Compared with the commonly used intermittent NIR illumination at both 660 and 808 nm, the persistent motion of ultrasound-activated NPs enhances cellular uptake and long-lasting PTT and intracellular NO levels to combat tumor cells without the use of any chemotherapeutic drugs. The ultrasound-activated persistent motion promotes intratumoral accumulation and tumor distribution of PTT/NO therapeutics and exhibits significantly higher tumor growth inhibition, longer animal survival, and larger intratumoral NO levels than those who experience external NIR illumination. Thus, this study demonstrates a strategy to activate PL emissions and construct PL-excited nanomotors for phototherapy in deep tissues.

Synthesis of multifunctional superparamagnetic mesoporous ZnMnFe2O4@Fe–CaSiO3 core-shell for medical applications

Herein, we report the synthesis of a mesoporous calcium silicate superparamagnetic nanoparticle as ZnMnFe2O4@Fe–CaSiO3 core-shell. This core-shell nanocomposite reveals excellent properties such as mesoporous nanocomposite, superparamagnetic at room temperature, low toxicity, large surface area, tunable pore size, and easy surface manipulation. The core nanocomposite (ZnMnFe2O4) is synthesized by the hydrothermal method, which shows a superparamagnetic behavior with an excellent saturation magnetization of 52.09 emu/g. The core-shell structure is prepared by a micellar-assisted sol-gel method, which uses a copolymer to create pores in the structure of CaSiO3. To improve the magnetic properties of the core-shell structure, different percent of Fe ions (0%, 5%, and 10%) are doped onto the calcium silicate structure; as for 10% Fe, i.e., ZnMnFe2O4@Fe10–CaSiO3, saturation magnetization and coercive magnetic field are 34.543 emu/g and 1Oe, respectively. In this configuration of nanocomposite, the pore volume and superparamagnetic property increase simultaneously. In addition, the core-shell mesoporous ZnMnFe2O4@Fe–CaSiO3 nanocomposite reveals comparable mesoporous channels (3.4–6 nm), while the amorphous structure of CaSiO3 has not been changed. These core-shell mesoporous superparamagnetic nanocomposites are evaluated in terms of drug loading and release using epirubicin (EPI) as a model drug. It is found that the increase of iron ions improves the capacity to stabilize the pH environment. Additionally, the mesoporous Fe–CaSiO3 nanostructures demonstrate a sustained drug release property that could be used in local drug delivery therapy. Therefore, these mesoporous superparamagnetic nanostructures would be a promising multifunctional platform for local drug delivery, magnetic resonance imaging, magnetic hyperthermia, and bone tissue regeneration.

Mussel-Inspired Polydopamine Composite Mesoporous Bioactive Glass Nanoparticles: An Exploration of Potential Metal-Ion Loading Platform and In Vitro Bioactivity.

Exploring new approaches to realize the possibility of incorporating biologically active elements into mesoporous silicate bioactive glass nanoparticles (MBG NPs) and guaranteeing their meso- structural integrity and dimensional stability has become an attractive and interesting challenge in biomaterials science. We present a postgrafting strategy for introducing different metal elements into MBG NPs. This strategy is mediated by polydopamine (PDA) coating, achieving uniform loading of copper or copper-cobalt on the particles efficiently and ensuring the stability of MBG NPs in terms of particle size, mesoporous structure, and chemical structure. However, the PDA coating reduced the ion-binding free energy of the MBG NPs for calcium and phosphate ions, resulting in the deposition of minimal CaP clusters on the PDA@MBG NP surface when immersed for 7 days in simulated body fluid, indicating the absence of hydroxyapatite mineralization.

Quantitative evaluation of artifact expression in conebeam computed tomography of mesoporous calcium silicate nanoparticles as a promising root canal sealer

We aimed to quantitatively compare the area and volume of artifacts in cone beam computed tomography produced by mesoporous calcium silicate nanoparticles (MCSNs), AH Plus sealer, and iRoot SP sealer when used as root canal sealers. We prepared 40 single-rooted mandibular premolars and divided them into an MCSN sealer group, an AH Plus sealer group, an iRoot SP sealer group, and a no-sealer (control) group. We filled the canals with gutta-percha using the single-cone method and subjected them to conebeam computed tomography before and after the placement of root fillings using the same exposure parameters. We evaluated the images to quantify the areas of hyperdense and hypodense artifacts and non-affected teeth and reconstructed 3-dimensional image models of the materials to study volume distortion artifacts. The MCSN sealer group produced a significantly smaller hyperdense and volume distortion artifacts than the AH Plus and iRoot SP groups (P < .01), but the area and volume of hypodense artifacts did not differ significantly among the groups (P > .05). When used as a root canal sealer, MCSNs generate a significantly smaller area and volume of hyperdense artifacts than AH Plus and iRoot SP sealers. By significantly reducing the generation of high-density artifacts, MCSNs may facilitate the evaluation of root canal filling quality and the diagnosis of root canal abnormalities.

Properties of CrOx/MCM-41 and Its Catalytic Activity in the Reaction of Propane Dehydrogenation in the Presence of CO2

Propylene is an important raw material for the production of many valuable compounds, especially polypropylene, the consumption of which continues to grow every year. The reaction of oxidative dehydrogenation of propane, where carbon dioxide is used as a mild oxidant, is a promising method for producing propylene. At the same time, the problem of utilization of greenhouse gas CO2 is partially solved. The synthesis and analysis of the physicochemical properties of mesoporous silicate MCM-41 and supported catalysts CrOx/MCM-41 prepared on its basis were carried out. These catalysts were prepared using incipient wetness impregnation. The support and catalysts were characterized by the methods of low-temperature nitrogen adsorption, TG-DTA, XRD, SEM, TPR-H2, UV/Vis diffuse reflectance spectroscopy, and small-angle X-ray scattering. It is shown that chromium is present in the samples simultaneously in the form of Cr3+ and Cr6+. The catalytic tests were performed in the range of 550–700 °C. The highest selectivity for propylene was observed for the 5%Cr/MCM-41 catalyst and was 76% at a temperature of 650 °C with a propane conversion of 20%. The deposited catalysts Cr/MCM-41 and Cr/SiO2 (Acros) were compared. The propylene selectivity for the MCM-41-supported catalyst was ~1.5 times higher than that for the SiO2-supported catalyst.

Fast and effective sorption of radioactive Sr(II) onto mesoporous silicate

Abstract A mesoporous silicate material (MS) was effectively synthesized and applied as a solid sorbent for removal of radioactive Sr(II) ions from aqueous solution. MS was characterized using different tools including N2 adsorption-desorption analysis, FT-IR, XRD and SEM. The synthesized material has crystalline, porous nature and exhibited a large surface area of about 905.18 m2 g−1. The uptake of Sr(II) ions onto MS was investigated under different batch experimental conditions involving pH, equilibrium time, sample weight and initial concentration of Sr(II) ions. About 98 % of Sr(II) radionuclides were uptaken at pH 12 in the first minute. Different isotherm models (Langmuir, Freundlich, Dubinin-Radushkevich and Temkin) were applied to analyze the obtained experimental sorption equilibrium data. The Langmuir isotherm model was aligned well with the sorption data. The maximum sorption capacity (Q max) of MS towards strontium ions attained the value 0.991 mmol/g. The parameters (ΔG°, ΔH° and ΔS°) were calculated from thermodynamic study and their values showed that sorption process of Sr(II) ions on MS is strong, take place spontaneously, and considered as endothermic process. The synthesized MS had the ability to efficiently remove Sr(II) radionuclides even in the presence of Na+ and Ca2+ as competing cations in aqueous solution. Among the studied desorbing agents, CaCl2 was the best one for desorbing Sr(II) radionuclides loaded onto MS. The synthesized MS was reused for sorption of strontium up to four cycles with acceptable efficiency.

Carboxy-functionalized imidazolium ionic liquid immobilized on MCM-41 as recyclable catalysts for carbon dioxide conversion to cyclic carbonates

Integrating multifunctional active sites into an appropriate porous material is a promising strategy to achieve great catalytic performance for CO2 cycloaddition. Herein, carboxy-functionalized imidazolium ionic liquid were successfully anchored onto the MCM-41 mesoporous silicates. The resultant MCM-41-Imi/COOH integrates hydrogen bond donor, Lewis base and nucleophilic ionic sites, and possesses a high surface area and mesopore structure. As-prepared catalyst achieves a good catalytic activity for CO2 cycloaddition with propylene oxide under cocatalyst- and solvent-free conditions. Moreover, the catalyst MCM-41-Imi/COOH exhibits the good cycling stability and versatility to various epoxides. In particular, the catalyst shows a satisfactory catalytic activity for catalyzing dilute CO2 conversion to cyclic carbonate. Furthermore, a possible reaction mechanism for the cycloaddition of CO2 with propylene oxide over the catalyst MCM-41-Imi/COOH was proposed.

First successful synthesis of an Al-rich mesoporous aluminosilicate for fast radioactive strontium capture

Al-rich zeolites such as NaA (Si/Al = 1.00) have been widely applied to remove radioactive 90Sr2+ because of their high surface charge density enabling efficient ion-exchange of multivalent cations. However, due to the small micropore diameters of zeolites and large molecular size of strongly hydrated Sr2+, Sr2+-exchange with zeolites suffers from very slow kinetics. In principle, mesoporous aluminosilicates with low Si/Al ratios close to unity and tetrahedrally coordinated Al sites can exhibit both high capacity and fast kinetics in Sr2+-exchange. Nonetheless, the synthesis of such materials has not been realized yet. In this study, we demonstrate the first successful synthesis of an Al-rich mesoporous silicate (ARMS) using a cationic organosilane surfactant as an efficient mesoporogen. The material exhibited a wormhole-like mesoporous structure with a high surface area (851 m2 g–1) and pore volume (0.77 cm3 g–1), and an Al-rich framework (Si/Al = 1.08) with most Al sites tetrahedrally coordinated. Compared to commercially applied NaA, ARMS exhibited a dramatically improved Sr2+-exchange kinetics (>33-fold larger rate constant) in batch adsorption while showing similarly high Sr2+ capture capacity and selectivity. Due to the fast Sr2+-exchange kinetics, the material also exhibited 3.3-fold larger breakthrough volume than NaA in fixed-bed continuous adsorption.

Synthesis of mesoporous magnesium silicate from coal gangue for efficient CO2 adsorption at room temperature

Solid adsorbents are widely investigated for CO2 capture, but some of them show low cycle stability and high synthesis cost. In this work, coal gangue (CG) as the raw material reacts with MgCl2 by the stirring way to synthesize mesoporous magnesium silicate (MMS) for efficient CO2 adsorption at room temperature. Meanwhile, the optimal synthesis condition of MMS was finally confirmed on the basis of single factor and response surface strategies: pH = 10.00, 1: 1 of Mg/Si molar ratio, 80 °C of the reaction temperature, and 2 h of reaction time. Under this condition, the as-synthesized MMS presented 1.02 mmol/g of CO2 adsorption amount at 25 °C, which adsorbed 33 times more CO2 than N2. The MMS owns a 373.00 m2/g of specific surface area and mesoporous structure. The adsorption thermodynamics and cycle performance of CO2 were discussed. After 10 cycles, the adsorption amount of MMS still maintained to 86 % of the initial value. The adsorption is exothermic and spontaneous physical process. The MMS was shown to have high CO2 adsorption capacity and selectivity. This work presents an application potential for the efficient utilization of CG and the development of CO2 adsorbents.

Review on the Catalytic Conversion of Naphtha to Aromatics: Advances and Outlook

Naphtha is the main feedstock used in the production of gasoline and benzene, toluene, and xylene (BTX) aromatics, which are widely applied as chemical intermediates in the fields of packaging, synthetic fibers, and solvents. This article reviews the recent literature regarding the catalytic conversion of naphtha to higher-value BTX in terms of catalysts used, catalyst properties, reaction mechanisms, kinetic modeling, operating conditions, and product selectivity. Most studies focused on ZSM-5 and ZSM-5 modified using Ga, Zn, Ni, Co, Cu, Fe, Mo, W, Sn, etc. The promoting effects of metals and catalyst properties on naphtha conversion and the selectivity toward aromatics were critically analyzed. Pt-promoted zeolite L exhibited an excellent catalytic performance in naphtha aromatization for the selective production of benzene using n-hexane. Other studies investigated different types of zeolites, such as ZSM-11, BEA, X, Y, MOR, ZRP, and TsVM high-silica zeolites, with distinct properties. Nonzeolitic catalysts included Pt, Re, and Sn supported on Al2O3; activated carbon; and mesoporous silicates (MCM-41 and SBA-15). Finally, the challenges and perspectives of naphtha aromatization related to emerging naphtha types, cofeeding, and improved catalysts are highlighted.

Chromium adsorption from water using mesoporous magnetic iron oxide-aluminum silicate adsorbent: An investigation of adsorption isotherms and kinetics

One of the prominent issues of the environment is water quality deterioration due to release of industrial wastewater containing heavy metals. This research work focused on the synthesis of mesoporous magnetic iron oxide-aluminum silicate (Fe3O4-Al2SiO5) adsorbent via deposition-precipitation method and to assess its efficiency for chromium (VI) adsorption. The study demonstrated that the prepared mesoporous adsorbent exhibit large surface area (476.0 m2g-1) and mesoporous structure, which enhances the adsorbate adsorption. From the results it was noticed that maximum removal (99.9%) was occurring at neutral pH and the adsorption data was find in best fitting to both Langmuir isotherm as well as with pseudo-second-order kinetic models. The study further concluded that the mesoporous adsorbent can be reused following several cycles and that very slight effect of coexisting competitive ions was noticed. The study recommends that after further modification and activation, the desired mesoporous adsorbent material could be utilized for water purification at industrial level.