Mesoporous Silicate Research Articles

Preparation and oxidative desulfurization performances of modified SBA-15 supported polyacid metal oxolates

In this study, eight composite catalysts were prepared by loading (CTAB)3H3[PW9V3O40] (active components) onto amino-functionalized mesoporous titanium silicate Ti-SBA-15(supports). In order to study the effects of different Ti contents and different active components on the catalytic performances of the catalysts, 30 %(CTAB)3H3[PW9V3O40]/NH2–Ti-SBA-X (X = 0, 25, 50, 75, 100) and X%(CTAB)3H3[PW9V3O40]/NH2–Ti-SBA-50 (X = 20, 40, 50) were obtained and characterized. The oxidative desulfurization performances of the composite catalysts were explored. It was found that catalyst 40 %(CTAB)3H3[PW9V3O40]/NH2–Ti-SBA-50 exhibits the optimal oxidative desulfurization performance. This is because the incorporation of SBA-15 with an appropriate amount of Ti (n(Si)/n(Ti) = 50) can improve the acidity and stability of mesoporous silica. The successful substitution of CTAB (n(CTAB)/n(H6PW9V3O40) = 3) in the active component can reduce the mass transfer resistance and speed up the reaction rate. 3-Aminopropyltriethyl silane (APTES) acts as a silane coupling agent to graft amino groups onto mesoporous molecular sieve SBA-15, which can enhance the interaction between heteropolyacids and carriers. Under the synergistic effect of the active component and the support, the total removal rate of the optimal catalyst with a total concentration of 1000 ppm sulfur compounds in the simulated fuel was 94.44 %. After four cycles, the total desulfurization rate of the catalyst can reach 91.28 %.

Comparative study of silica-based porous materials in the purification of radioactive wastewater

A significant challenge in the treatment of low-level radioactive wastewater is the effective purification of low-concentration radionuclides. Silica-based adsorbents are advantageous for the deep-purification of low-concentration metal ions. This study investigates three primary types of silica-based adsorbents: functionalized mesoporous silica, various modified zeolites, and mesoporous calcium silicate hydrate (C-S-H). These adsorbents were synthesized and their deep-purification effects on heavy metals and radionuclides were compared. The results indicated that mesoporous silica showed relatively poor adsorption for most metal ions. Zeolites outperformed mesoporous silica, with Zn framework-modified zeolites showing enhanced adsorption for several metal ions. Notably, C-S-H displayed superior adsorption performance, achieving high adsorption capacities for various metal ions and radionuclides. Specifically, at a dose of 0.5 g/L, the adsorption efficiency of C-S-H for numerous radionuclides in nuclear power plant wastewater exceeded 92–99 %, highlighting its potential for practical applications. An in-depth analysis of the physical and chemical structure and the adsorption mechanisms of C-S-H revealed its large mesoporous structure and electrostatic attraction to cations across a wide pH range. Multivalent cations were removed through exchange with Ca2+ in C-S-H, whereas monovalent cations were removed through exchange with Na+ in C-S-H. The cyclic structure of silica-oxygen tetrahedra in C-S-H, which promotes large pore formation and provides abundant ion exchange sites, underpins its excellent adsorption properties. This study offers valuable insights for the selection and application of silica-based materials in radioactive wastewater treatment.

3D printed polycaprolactone/gelatin/ordered mesoporous calcium magnesium silicate nanocomposite scaffold for bone tissue regeneration.

Tissue engineering scaffolds are three-dimensional structures that provide an appropriate environment for cellular attachment, proliferation, and differentiation. Depending on their specific purpose, these scaffolds must possess distinct features, including appropriate mechanical properties, porosity, desired degradation rate, and cell compatibility. This investigation aimed to fabricate a new nanocomposite scaffold using a 3D printing technique composed of poly(ε-caprolactone) (PCL)/Gelatin (GEL)/ordered mesoporous calcium-magnesium silicate (om-CMS) particles. Different weight ratios of om-CMS were added and optimized, and a series of scaffolds were constructed for comparison purposes, including PCL 50%/Gel 50%, PCL 50%/Gel 45%/om-CMS%5, and PCL 50%/Gel 40%/om-CMS%10. The optimized weight ratio of om-CMS was 10% without leaving behind negative effects on the filaments' structure. The scaffolds' physical and chemical properties were assessed using various techniques, and their degradation rate, bioactivity potential, cell viability, attachment, and ALP activity were evaluated in vitro. The results demonstrated that the PCL 50%/Gel 40%/om-CMS10% scaffold had promising potential for further studies in bone tissue regeneration.

Synthesis and characterization of mesoporous silicate as core and low generation polyamidoamine dendrimer as shell for delivery of 5-fluorouracil from their nano complex

Modern nanomedicine delivers drugs to malfunctioning cells. Several synthetic processes can change the shape, particle size, polydispersity index, surface area, and porosity of mesoporous silica nanoparticles (MSNs). Polyamidoamine (PAMAM) dendrimers are attractive polymers with circular forms, uniform distribution, well-structured branching, internal cavities, and surface terminal groups. The objective of this study is to deliver 5-fluorouracil (5-FU) as passive targeting to carcinogen cells via MSN-PAMAM-G3 nanoparticles. This study involved the direct and adaptable synthesis of MSN as the core vehicle, together with third-generation PAMAM dendrimers as the vehicle shell, with the goal of delivering the 5-FU in a targeted and controllable manner. Tetraethyl orthosilicate (TEOS) and cetyltrimethylammonium bromide (CTAB) are used as templates to make the center nanoparticle. Methyl acrylate (MA) and ethylenediamine (EDA) are monomers that cause the formation of branches in PAMAM. The obtained particles were fully characterized in terms of particle size, polydispersity index, zeta potential, thermal behavior, morphology, pore diameter, pore volume, and specific surface area. The particle size of MSN-PAMAM-G3s showed around 187.71 ± 3.97 nm, with a polydispersity index of 0.17 ± 0.01 and zeta potential of 32.17 ± 1.30 mV. By reducing the ratio of drug to vehicle from 1 to 0.25, a significant increase in the EE% of 5-FU from 21.36 ± 0.70 to 43.12 ± 0.67 was observed. The release of 5-FU from the vehicle (5-FU@MSN and 5-FU@MSN-PAMAM-G3) was shown to be considerably higher in an acidic medium (pH = 5.5) in comparison to a neutral medium (pH = 7.4) (P-value<0.05). Furthermore, in both acidic and neutral conditions, 5-FU release was sustained from the vehicle rather than the 5-FU solution. Our research revealed that the MSN-PAMAM-G3 nanoparticles effectively regulated the encapsulation and release of 5-FU, providing pH-sensitive and sustained medication delivery. It is asserted that this nanocarrier has the potential to effectively deliver 5-FU to cancer cells.

Halloysite-derived hierarchical cobalt silicate hydroxide hollow nanorods assembled by nanosheets for highly efficient electrocatalytic oxygen evolution reaction

The oxygen evolution reaction (OER) is regarded as the bottleneck of electrolytic water splitting. Thus, developing robust earth-abundant electrocatalysts for efficient OER has received a great deal of attention and it is an ongoing scientific challenge. Herein, hierarchical hollow nanorods assembled with ultrathin mesoporous cobalt silicate hydroxide nanosheets (denoted as CoSi) were successfully fabricated, using the silica nanotube derived from halloysite as a sacrificial template, via a simple hydrothermal method. The resulting cobalt silicate hydroxide nanosheets stack with thicknesses ∼10 nm, as confirmed by transmission electron microscopy. The elaborated nanoarchitecture possesses a high specific surface area (SSA) allowing good exposure to the cobalt active centers exhibiting superior catalytic activity vs analogs synthesized using sodium silicate. Among all as-prepared CoSi samples, those synthesized at 150 °C (CoSi-150) exhibited the minimum overpotential of ∼347 mV at a current density of 10 mA cm–2. In addition, CoSi-150 also exhibited superior performance against typical cobalt-based catalysts, and its surface hydroxyl groups were beneficial for the enhancement of OER performance. Furthermore, the CoSi-150 showed excellent durability and stability after the 105 s chronopotentiometry test in 1 M KOH. This design concept provides a new strategy for the low-cost preparation of high-quality cobalt water splitting electrocatalysts.

A nanoenzyme reactor fueled by a High-Glucose microenvironment for augmented diabetic tumor therapy

Diabetes is recognized as an independent risk factor for the onset and advancement of cancer. However, there has been limited emphasis on investigating the diabetic tumor microenvironment (TME) and harnessing its inherent microenvironmental distinctions to facilitate tumor ablation. The management of cancer with diabetes is often challenging. Herein, an activatable hollow mesoporous manganese silicate (H-Mn)/indocyanine green (ICG)/glucose oxidase (GOX) nanoenzyme (H-MIG) was developed for diabetic tumor therapy. This micro-reactor consumes glucose to trigger a sequential cascade reaction to biologically amplify the antitumor effect under hyperglycemia conditions. H-Mn degrades within the TME, releasing O2 and Mn2+. The presence of O2 promotes GOX-induced glucose consumption, leading to the subsequent production of H2O2. This glucose-fueled oxidation also provides reactants for chemodynamic therapy, as H2O2 and Mn2+ in the TME subsequently undergo a Fenton-like reaction. In addition, by inhibiting the expression of the heat shock protein 90, which is highly expressed in diabetic TME, GOX enhances ICG-guided mild-temperature photothermal therapy. In vitro and in vivo experiments demonstrated that the domino effect fueled by this high-glucose TME improves anticancer efficacy. By exploiting the complementary cascade reactions, this endogenous enzyme-based strategy could inspire the design of more promising advanced platforms for more efficient diabetic cancer therapy.

A unified description of ion exchange and complete adsorption isotherms, including cluster growth and cavity filling

In the context of micro- and mesoporous materials, the interpretation of ion exchange and gas adsorption isotherms rarely covers the full information content of the experimental data. Based on our earlier work regarding the role of entropy in multiple equilibria, we have revisited cation exchange data of zeolite A in more detail and addressed the analysis of Ar and N2 adsorption isotherms of nonporous, microporous and mesoporous silicates. The previously reported analysis is thereby extended and improved. The theory is presented in a unified and compact manner through rigorous application of the concept of fractional amount, including particle distribution, cluster growth, and cavity filling. A result is that the structure of mesoporous silica MCM-41 can be described as consisting of the main channel and two types of cavities, which can be interpreted as surface roughness. In a further step, the information delivered by the inflection points in type I, II and IV gas adsorption isotherms is considered. The adsorption of simple gases begins with the formation of a monolayer on the pristine surface. The inflection point thereby represents the start of a new process, indicating that the adsorption isotherms must be understood as the signature of several sequential chemical equilibrium steps. Information can be extracted by inspecting this signature more closely. The results demonstrate the ability of the reported procedure to elicit additional insight including structural features from experimental equilibrium isotherm data.

Effect of Chitosan Addition on Porosity of Rice Husk Calcium Silicate Used for Free Fatty Acid Adsorbent from Palm Oil

Studies have been done on developing calcium silicate pores derived from rice husk with and without including chitosan as a template. The chitosan solution was supplemented with sodium silicate derived from rice husk, and then CaCl2 was added. The calcium silicate was calcinated at 900ºC for 4 h. The calcium silicate obtained was characterized using X-ray diffraction (XRD), fourier transform infrared (FT-IR), and Brunauer-Emmett-Teller (BET) analysis. The XRD analysis showed the presence of diffraction peaks corresponding to Wollastonite (CaSiO3) crystals, Wollastonite 2m (CaSiO3), Alite (Ca3SiO5), and larnite (Ca2SiO4). Next, the FT-IR spectrum exhibits Si-O-Si, Si-O-Ca, and Si-OH functional groups, suggesting the presence of calcium silicate material. The BET study of calcium silicate using chitosan templates revealed a pore size of 3.88 nm, a pore volume of 0.1577 cc/g, and a surface area of 81.1519 m2/g. The BET analysis results obtained differed from those of the BET analysis of calcium silicate conducted without using chitosan templates, which were 2.06 nm, 0.069 cc/g, and 13.531 m2/g, respectively. The developed mesoporous calcium silicate was employed as an adsorbent to decrease the concentrations of free fatty acids in palm oil. The acid-base titration method is used to evaluate quantities of free fatty acids. The results obtained from the computation of free fatty acid levels indicate a decline in the concentration of free fatty acids in palm oil. The concentration of free fatty acids derived from palm oil was 1.23%. Therefore, mesoporous calcium silicate-free fatty acids at a concentration of 1.06% resulted in an 86.1% reduction.

Using solid waste to treat wastewater: Preparation of flowerlike calcium silicate hydrate from coal fly ash for cadmium removal

Efficient utilization of Coal fly ash (CFA) and ingenious treatment of cadmium (Cd (II)) in the water environment are interesting topics. In this paper, a mesoporous floral calcium silicate hydrate (MCSH) for removal of Cd (II) was prepared by low temperature hydrothermal synthesis using CFA desilication solution. Different synthesis parameters (molar ratio of Ca to Si (Ca/Si), temperature, time) of MCSH were investigated and optimized. All synthesized MCSH showed good adsorption properties for Cd (II), and MCSH synthesized at Ca/Si molar ratio of 1.0, temperature of 363 K and time of 120 min had the optimum Cd (II) adsorption capacity of 357.43 mg/g. The effects of solution pH, MCSH dosage, coexisting cations and ionic strength on the Cd (II) adsorption performance by MCSH were further considered systematically. The adsorption process was a spontaneous and endothermic process, conformed to the pseudo-second-order kinetic and Langmuir isothermal model. The main mechanism of Cd (II) removal by MCSH was the precipitation between Cd (II) and OH– released by MCSH, accompanied by ion exchange, surface complexation and electrostatic adsorption. The mesoporous flowery MCSH prepared from CFA provides an satisfactory solution for the utilization of solid waste resources and the purification of heavy metal wastewater.

Efficacy of Ga3+ ions on structural, biological and antimicrobial activity of mesoporous lithium silicate bioactive glasses for tissue engineering

Mesoporous bioactive glass nanoparticles (MBGNPs) containing therapeutic ions have shown significant promise in the realm of hard and soft tissue repair and regeneration, owing to their multifunctional biological properties. In this study, gallium-incorporated silica-based gallium incorporated MBGNPs (Ga-MBGNPs) with fixed amount of Li2O (8 mol %) were synthesized using an emulsion-assisted sol-gel method. The impact of Ga2O3 integration into the silicate glass network was evaluated by investigating the microtextural properties. The results confirmed the production of spherical-shaped, nano-sized, amorphous particles with an enhanced specific surface area and ordered hexagonal meso-porosity (10–20 nm) in the developed Ga-MBGNPs. The in vitro bioactivity, assessed through hydroxyapatite (HAp) layer formation in simulated body fluid (SBF), over varying time intervals (0, 1, 3, 7, 14 & 21 days), revealed pronounced formation of short rod-like carbonated HAp with increasing immersion time and Ga3+ content in all glasses. However, a delayed apatite formation was observed for composition-dependent Ga-4 and Ga-5 MBGs during the initial incubation periods (1, 3, and 7 days). Further, the presence of Li + ions along with Ga3+ enhanced the apatite deposition when compared with the only Ga3+ inclusion. Evaluation of degradation rate and pH values indicated enhanced apatite formation with lower Ga ion content, while a slight reduction was noted with higher Ga ion content, attributable to the presence of reactive Si–O–Si bonds. Furthermore, analysis using a Zeta potential analyzer confirmed the dispersibility and bioreactivity of all glass powders owing to their higher negative surface charge. Moreover, Ga-MBGNPs exhibited notable antimicrobial effects against both E. coli and S. aureus bacteria due to the release of Ga3+ ions. Overall, the findings suggest that the incorporation of Ga in MBGNPs renders them potential multifunctional candidates for expediting the healing of bone tissue injuries in biomedical applications.

Fabrication and characterization of mesoporous calcium silicate and silver-incorporated mesoporous calcium silicate nanoparticles with low cytotoxicity and antibacterial properties as a dental biomaterial

AimThis study aimed to fabricate and characterize Mesoporous calcium silicate nanoparticles (MCSNs) and silver-incorporated Mesoporous calcium silicate nanoparticles (Ag-MCSNs) as bioactive nanoparticles either for hybridization with contemporary endodontic materials to improve their bioactivity by using (MCSNs) as a drug delivery system, and to achieve both low cytotoxicity and enhanced antibacterial activity by incorporating Ag which is avery potent antibacterial agent to form (Ag-MCSNs) as new multifunctional materials. MethodsThe MCSNs and Ag-MCSNs nanoparticles were made using the template method. Both nanoparticles' mesoporous structure, specific surface area, pore volume, pore size, and shape were examined and characterized by FTIR, XRD, EDS, DLS, and FE-SEM. The ion release, pH change, cytotoxicity by MTT assay, and antibacterial properties against planktonic Enterococcus faecalis were further investigated by colony forming units (CFUs) counting technique. ResultMCSNs nanoparticles were prepared and successfully incorporated with silver as Ag-MCSNs. MCSNs and Ag-MCSN nanoparticles had the characteristic mesoporous material shape and over time showed sustained ion release (Ca2+,Si4+ and Ag+) ,with an alkaline pH value (8.2–9.0). Both materials showed no obvious cytotoxicity but more cell viability with MCSNs (vitality value is >70%). Both nanoparticles showed antibacterial activity against Enterococcus faecalis (p < 0.05). With MCSNs containing Ag (Ag-MCSNs) showing higher antibacterial effect. ConclusionBoth mesoporous calcium silicate nanoparticles (MCSNs) and mesoporous calcium silicate nanoparticles loaded with silver (Ag-MCSNs) displayed a characteristic mesoporous structure, ion release, alkaline pH, minimal cytotoxicity, and outstanding antibacterial performance with MCSNs containing Ag (Ag-MCSNs) showing higher antibacterial effect. This substance may be improved to provide a better root canal filler material, sealer, or novel intracanal medicament in dentistry.

Engineering surface framework TiO6 single sites for unprecedented deep oxidative desulfurization.

Catalytic oxidative desulfurization (ODS) using titanium silicate catalysts has emerged as an efficient technique for the complete removal of organosulfur compounds from automotive fuels. However, the precise control of highly accessible and stable-framework Ti active sites remains highly challenging. Here we reveal for the first time by using density functional theory calculations that framework hexa-coordinated Ti (TiO6) species of mesoporous titanium silicates are the most active sites for ODS and lead to a lower-energy pathway of ODS. A novel method to achieve highly accessible and homogeneously distributed framework TiO6 active single sites at the mesoporous surface has been developed. Such surface framework TiO6 species exhibit an exceptional ODS performance. A removal of 920ppm of benzothiophene is achieved at 60°C in 60min, which is 1.67 times that of the best catalyst reported so far. For bulky molecules such as 4,6-dimethyldibenzothiophene (DMDBT), it takes only 3min to remove 500ppm of DMDBT at 60°C with our catalyst, which is five times faster than that with the current best catalyst. Such a catalyst can be easily upscaled and could be used for concrete industrial application in the ODS of bulky organosulfur compounds with minimized energy consumption and high reaction efficiency.

Front Cover: Switching Product Selectivity in Immobilized Tungstate Catalysts by Control of Hydrophobicity of Mesoporous Silicate Supports (ChemistryEurope 2/2024)

Front Cover: Switching Product Selectivity in Immobilized Tungstate Catalysts by Control of Hydrophobicity of Mesoporous Silicate Supports (ChemistryEurope 2/2024)

Synthesis and characterization of surface-modified magnetic mesoporous silicate materials for phosphate adsorption.

The magnetic mesoporous silica material, Mag-MCM-41, was synthesized by coating magnetite (Fe3O4) nanoparticles with a mesoporous material called MCM-41. Mag-MCM-41 and modified nanomaterials Mag-MCM-41-NN and Mag-MCM-41-NN-Fe+3 which were modified with aminopropyl functional groups. In water and wastewater, phosphate anions are considered significant contaminants due to their detrimental impact on the environment. They promote the growth of algae, leading to eutrophication. The purpose of this study is to investigate the removal of phosphate anions from aqueous solutions using modified magnetic silica particles. The Mag-MCM-41 material exhibits hexagonal properties and belongs to the class of "mesoporous" materials. It has a surface area of 923 m2.g-1, which was determined through N2 adsorption-desorption isotherms, FTIR, TEM, BET, and SAXS analysis. Kinetic and adsorption isotherm studies were conducted using Mag-MCM-41, Mag-MCM-41-NN, and Mag-MCM-41-NN-Fe+3 adsorbents to examine the behavior of phosphate anions. The kinetic and adsorption isotherm studies of phosphate anions revealed that the adsorption process on Mag-MCM-41, Mag-MCM-41-NN, and Mag-MCM-41-NN-Fe+3 adsorbents followed the chemical adsorption mechanism. Phosphate adsorption on all adsorbents occurred in a monolayer, and the MCM-41-NN-Fe+3 adsorbent exhibited the highest maximum adsorption capacity (qm) value of 112.87 mg.g-1 compared to the other adsorbents.

Removal of phenoxy acid herbicide from water by magnetic mesoporous silicate

Superparamagnetic iron (II,III) oxide (Fe3O4)–MCM-41 was successfully synthesised using a direct hydrothermal route and was utilised as an excellent adsorbent for the removal of the herbicide 2,4-dichlorophenoxyacetic acid from aqueous solution. The superparamagnetic mesoporous adsorbent was fully characterised using X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, nitrogen (N2) sorption and vibrating-sample magnetometry (VSM). The synthesised adsorbent exhibited a high specific surface area of 444 m2/g, making it a suitable candidate for adsorption, where it provided a higher adsorption capacity. Based on the VSM study, the recorded saturated magnetisation was 15.9 emu/g, which confirmed the viability of easily separating the adsorbent from an aqueous medium using a magnet. The ability of iron (II,III) oxide–MCM-41 to adsorb the herbicide 2,4-dichlorophenoxyacetic acid from water was tested considering various parameters, such as pH, adsorbent dosage, contact time and pollutant concentration. The effectiveness of iron (II,III) oxide–MCM-41 in removing the herbicide reached its highest peak at pH = 5, 0.05 g adsorbent, 60 min contact time and 10 mg/l 2,4-dichlorophenoxyacetic acid. The maximum removal efficiency under optimum conditions was 94.8%. Based on the experimental data and kinetic studies, the adsorption process followed a pseudo-second-order kinetic and Langmuir isotherm model.

Switching Product Selectivity in Immobilized Tungstate Catalysts by Control of Hydrophobicity of Mesoporous Silicate Supports

AbstractNovel mesoporous silicates modified with imidazolium cation were applied as the support for peroxotungstate. Stepwise introduction of multiple functional groups to SBA‐15 was achieved by the combination of the direct and post‐synthesis procedures. The co‐condensation of tetraethoxysilane and 3‐(imidazolyl‐1‐yl)‐propyltriethoxysilane in the presence of the micelles of an amphiphilic surfactant yields the hydrophilic SBA‐15 type silicate support with the imidazole modifier locating into the mesopores. The hydrophobic environment of the supports was imparted by capping the residual silanols on the silicate surface with trimethylsilyl groups. The fluoroalkyl‐ or alkyl‐imidazolium cation‐anchored supports were derived from the corresponding imidazole‐functionalized precursors. The anion‐exchanging reaction between peroxytungstate and the imidazolium cation‐anchored supports yielded the corresponding tungstate‐immobilized catalysts. The hydrophilic catalyst with the fluoroalkyl‐imidazolium mediated alkene epoxidation with H2O2 in less polar solvents. The hydrophobic one, in contrast, produced diol through the epoxidation and following hydration in an aqueous solvent by the action of the highly Lewis acidic tungsten. The hydrophobic catalysts had the advantage of being more tolerant than hydrophilic catalysts, as evidenced by reusability tests. The activities of the alkyl‐imidazolium catalysts were lower than those of the corresponding fluoroalkyl‐imidazolium catalysts, indicating that the local structures surrounding the tungstate site affected the catalytic performance.

An innovative transportable immune device for the recognition of α-synuclein using KCC-1-nPr-CS2 modified silver nano-ink: integration of pen-on-paper technology with biosensing toward early-stage diagnosis of Parkinson's disease.

Parkinson's disease (PD), the second most frequent neurodegenerative illness, is a neurological ailment that produces unintentional or uncontrolled body movements, which should be diagnosed in its early stages to hinder the progression. Monitoring the concentration of α-synuclein (α-Syn) in body fluids can be one of the most efficient ways for PD early detection. In this work, a paper-based electrochemical immunosensor was designed for α-Syn bio-assay in human plasma samples based on encapsulation of the biotinylated antibody on novel dendritic fibrous nanosilica ((KCC-1-nPr-CS2)-Ab). For this purpose, a three-electrode system was prepared using stabilization of silver nano-ink on photographic paper. Then, the (KCC-1-NH-CS2)-Ab was immobilized on its surface and used to detect the target antigen (α-Syn). After characterization of the prepared substrate by FE-SEM and EDS, the redox behavior of the biosensor was evaluated using chronoamperometry techniques. Under optimal experimental conditions and using a label-free strategy, the engineered immunosensor showed a linear relationship between peak current and antigen concentration in the linear range from 0.002 to 128 ng mL-1 with the lower limit of quantification of 0.002 ng mL-1. Moreover, this work involves unprecedented use of conductive nano-inks for the manufacture of α-Syn immunosensor, which is aided by the use of a mesoporous silicate dendrimer in encapsulating the α-Syn antibody, thus offering a robust and simple point-of-care device for early PD diagnosis. The ability of the proposed platform to detect small amounts of α-Syn offers a promising approach to developing low-cost, sensitive, and transportable biosensors for Parkinson's disease screening in its early stages.

Magnetic Mesoporous Organo-Silicate Composite for Removing Organic Dyes from Aqueous Media

Water pollution has become a major problem for our modern ecological systems. According to the UN’s program on the environment, 80% of wastewater generated by humans goes untreated. This water contains pollutants ranging from human waste to industrial. When it eventually makes it into our waterways, it can have devastating effects on the ecosystem and potentially cause mass die off of the majority of organisms that reside there. The ones that remain are often wrought with disease and genetic mutation that can affect and destroy future generations. To make matters worse, the pollutants can remain viable and have destructive effects for years after their initial dumping. The Center for Public Integrity found that after 35,000 tons of industrial car waste was dumped onto occupied lands, the ground water was still found to be toxic 43 years later. For these reasons, cheap and effective ways of being able to remove pollutants, such as metals and dyes, is in high demand. One potential way of achieving this is using readily available adsorbent materials. Adsorbent materials can collect these pollutants, binding them, and making it easier for traditional filters to remove them from water sources [1-10]. The downside to these materials is that they are typically expensive to synthesize, have a low absorbance capacity. Magnetic Mesoporous Organo-Silicate (MMOS) Composite is a potential material that can get around these pressing issues. Mesoporous silicate has an organic function group with a high surface area. Although relatively ineffective on its own, combination with magnetic proprieties based on Fe3O4 and organic site based on cetrimonium bromide has been shown to be promising for the adsorption of water pollutants. In initial trials, the MSC composite has shown great promise in removing high concentrations of organic dyes from water sources. Additionally, this material has shown some effect in removing certain metal ions from aqueous solution. MSC was found to have a high absorbance capacity even at low dosages. Isotherm studies showed MCS was capable of removing 93% of Congo Red (CR) at high concentrations of adsorbent, while Methylene Blue (MB) showed 82% removal at high adsorbent concentrations. Adsorption was modeled using the Langmuir and Freundlich isotherm models in order to both describe the equilibrium isotherm and determine isotherm constants. Adsorption modeling found that CR fits to the Langmuir Model while MB fits to the Freundlich Model. Kinetics testing determined that MCS follows a first order reaction model for CR and a zero-order reaction model for MB. Future research into this material can look at alterations to its structure that would make it more viable for metal ions. References H Namkoong, E Biehler, G Namkoong, TM Abdel-Fattah, ACS omega 7 (44), 39931-39937 (2022)Omar H. Elsayed-Ali, Hani E. Elsayed-Ali and Tarek M. Abdel-Fattah, Journal of Hazardous Materials, 185 (2-3), 1550-1557 (2011).Alya Elsayed-Ali, Tarek Abdel-Fattah, Hani Elsayled-Ali, Hani, Journal of Chemical Education, 88(8), 1126-1129 (2011).TM Abdel-Fattah, ME Mahmoud, Chemical engineering journal 172 (1), 177-183 (2011)TM Abdel-Fattah, ME Mahmoud, MM Osmam, SB Ahmed, Journal of Environmental Science and health, part A 49 (9), 1064-1076 (2014)ME Mahmoud, AA Yakout, MT Abed El Aziz, MM Osman, TM Abdel-Fattah, Journal of Environmental Science and Health, Part A 50 (10), 1072-1081 (2015)ME Mahmoud, TM Abdel-Fattah, MM Osman, SB Ahmed, Journal of Environmental Science and Health, Part A 47 (1), 130-141 (2012)TM Abdel-Fattah, B Bishop, Journal of Environmental Science and Health, Part A 39 (11-12), 2855-2866 (2004)ME Mahmoud, MM Osman, SB Ahmed, TM Abdel-Fattah, The Scientific World Journal 2012 (2012)ME Mahmoud, SS Haggag, TM Abdel-Fattah, Polyhedron 26 (14), 3956-3962 (2007)

XYLITOL PRODUCTION FROM XYLOSE OVER ZIRCONIA-DOPED SILICA SBA-15 SUPPORTED RUTHENIUM CATALYSTS

Xylitol is an important product of xylan valorization — the main hemicellulose of birch and aspen wood. Xylitol is obtained by direct hydrogenation of xylose. In present study, the xylose was obtained by acid hydrolysis of birch wood xylan. The industrial catalyst for the xylitol production process is Raney nickel. Pyrophoricity, tendency to sintering, Ni leaching and contamination of the product are actual problems of its use. We have developed new supported ruthenium catalysts based on mesoporous silicate SBA-15 doped with zirconia. The proposed method of modification of SBA-15 by doping with zirconia improves the hydrothermal stability. The deposited Ru is present in the form of highly dispersed RuO2 particles and is distributed evenly. The catalysts are stable, safe and environmentally friendly. Their high catalytic activity allows the process to be carried out in very mild conditions – in pure water at 70 °C and a pressure of 5.5 MPa H2. While the catalysts provide 96-99% selectivity for xylitol. The introduction of the developed catalysts into the xylitol production might reduce the product purification cost of and the process energy consumption, thereby improving ecological and economic indicators of deep chemical processing of plant raw materials.

In vitro bioactivity and biocompatibility assessment of PCL/PLA–scaffolded mesoporous silicate bioactive glass: Role of boron activation

Bioactive glasses with rapid biodegradation and efficient biomineralization for damaged bone tissue repair remain deficient. Based on this fact, some new types of boron-activated mesoporous Bioactive silicate glasses (BMSGs) were made to determine the feasibility of achieving their improved mechanical strength, structure, porosity, biodegradability and bone healing performance. Four samples of the form xB2O3 – (80–x) SiO2 – 15CaO – 5P2O5 with x is 0, 5, 10, and 15 mol% were prepared using a unified sol-gel/evaporation induced self-assembly (SG-EISA) process. Furthermore, the solvent casting/partial leaching method was used to Scaffold the proposed BMSGs by polycaprolactone/polylacticacid (named as BMSG-PPS). The role of boron concentration fine-tuning in modifying the glasses morphology, structure, Bioactivity and Biocompatibility was assessed in vitro by immersing them in simulated body fluid (SBF) at various durations. Intense XRD peak at 31.7° confirmed the existence of crystalline hydroxyl carbonate apatite (HCA) in the glasses. Glass made with 10 mol% of boron (BMSG-PPS10) showed the strongest crystalline peak of HCA amongst all the studied samples. FESEM image of the Scaffold surface also revealed the presence of HCA agglomeration after 168 h of immersion in the SBF. The boron-free sample (BMSG-PPS0) showed strong agglomeration of HCA and Ca to P ratio (1.78±0.01) close to bone. After 168 h of immersion in the SBF solution, the symmetric stretching of PO43–and CO32–bands in the glass became more prominent. After 168 h of immersion in the SBF, the samples’ weight loss and solution pH correspondingly varied in the range of 5.66–7.37 % and 6.80–7.02. In addition, ICP–OES analyses of the glasses verified an increase of Si release in the SBF from the silicate network, indicating their rapid biodegradation. Briefly, the proposed BMSG–PPS with improved Bioactivity and Biocompatibility may be beneficial for various bio-medical implant coating applications.