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In this work, we present the preparation of hybrid materials constituted by a Metal Organic Framework (type CPO-27-Mg) and a mesoporous silica (type KIT-6) which were successfully assembled through an in situ hydrothermal method. The composites were characterised by powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), microscopic techniques (SEM and TEM), N2 adsorption–desorption isotherms at 77 K and CO2 adsorption at 273 K; these techniques confirmed the obtaining of hybrid materials and not simple physical mixtures. Finally, the hybrid materials were tested in the CO2 adsorption at different temperatures and from 0–10 bar of pressure, where the exposure to high relative humidity were also monitored. The CPO-27-Mg@KIT-6 (1 : 1) and (2 : 1) composites exhibited interesting values of CO2 adsorption capacity, compared with those reported in the literature. Therefore, this study opens new pathways for designing porous structured MOF-based materials with advanced gas separation performance. [ABSTRACT FROM AUTHOR]

Novel ceramic foams were obtained by the replica method, using bentonite as alternative raw material and polyurethane sponge as template, where the latter also controls the distribution of the pore size of these ceramics. The synthesis of the ceramics was carried out using slurries of bentonite clay with different percentages of sodium carboxymethyl cellulose as a binder, and evaluating different calcination temperatures. The effect of these factors on the textural and morphological properties of the ceramic foams was studied. The porosity measured by mercury intrusion showed that the total porosity of the ceramic foams decreases as the calcination temperature increases. Furthermore, a small quantity of porosity is generated after the burnout of the binder during the calcination step. This porosity is given by pore sizes from 0.05 to 3 µm and it was increased with the amount of the binder that was increased, which was also confirmed by scanning electron micrographs. The characterization of bentonite clay, polyurethane, coated polyurethane sponge and ceramic foams was also complemented with thermogravimetric analysis, nitrogen adsorption at 77 K, and mechanical strength measurements. [ABSTRACT FROM AUTHOR]

The equilibrium adsorption and kinetics of CO 2 on several microporous materials has been studied at 273, 283 and 293 K and gas pressures of up to 100 kPa. The porous materials used in this work were two zeolites (5A and 13X), two metal–organic frameworks (Basolite A100 and Basolite Z1200), an activated carbon and two pillared clays (Al-PILC and Zr-PILC). The isothermal and non-isothermal diffusion models were applied to calculate the diffusion time constants ( D 0 / r c 2 ) from the uptake curves. The non-isothermal model was found to fit the experimental data well over the whole range of adsorption rates. The values found for the zeolites, which ranged from 0.020 to 0.043 s −1 , were lower than those for the metal–organic frameworks and pillared clays, which ranged from 0.036 to 0.081 s −1 , in the same interval of temperatures. Furthermore, the values of the diffusion time constants were found to depend on gas pressure. The pressure-dependence of the diffusion time constants was studied using the Darken equation. Finally, activation energy values were estimated from the temperature-dependence for all materials and it was found to increase in the order: Z1200 < Al-PILC < 13X < AC < Zr-PILC < 5A; A100. [ABSTRACT FROM AUTHOR]

A computational and experimental screening of hypothetical and real compounds exhibiting different degrees of ethylenediamine grafted to the CPO-27-Mg or Mg-DOBDC skeleton is performed in order to determine the target composition that optimizes the CO2 adsorption properties under flue gas and air filtering conditions. On the basis of the [Mg2(dobdc)] formula, eighteen hypothetical models involving 15–100% of functionalization of the coordinatively unsaturated sites (CUS) were considered by means of Grand Canonical Monte Carlo simulations to evaluate the CO2 adsorption at 298 K. In addition, post-synthesis modification was applied to CPO-27-Mg leading to three kinds of samples exhibiting 15, 50, and 60% of CUS functionalization with ethylenediamine, named CPO-27-Mg-a, CPO-27-Mg-b and CPO-27-Mg-c. Compounds were characterized using elemental analysis, TGA, FTIR spectroscopy, PXRD and DSC. Finally, bare and functionalized CPO-27-Mg materials were evaluated using gas adsorption and microcalorimetry in the 0.001–1 bar range, which is pertinent for the mentioned applications. Valuable information related to design criteria for synthesis of tuned CO2 adsorbents is derived through this computational and experimental investigation. [ABSTRACT FROM AUTHOR]

The adsorption ofCO2on several microporous materialshas been measured at various temperatures (263, 273, 283, and 293K) over a wide range of pressures. The porous materials studied werethree zeolites (5A, 13A, and 13X), two metal–organic frameworks(Basolite A100 and Basolite Z1200), an activated carbon, and two pillaredclays (Al-PILC and Zr-PILC). The data obtained were fitted to theFreundlich, Langmuir, and Toth isotherms. Various methods were usedto calculate the Henry’s law constants. The values found forthe zeolites, which ranged from 8.95 to 36.02 mmol/kPa·g at 273K, were much higher than those for the metal–organic frameworks,activated carbon, and pillared clays, which ranged from 0.012 to 0.200mmol/kPa·g at the same temperature. The isosteric heats of adsorptionof CO2on the materials were calculated using the Clausius–Clapeyronequation, and the adsorbent–CO2affinity was foundto increase in the order Z1200 ≈ 13X ≈ 13A < 5A

In this study, we conducted experimental and Monte Carlo simulation studies in the grand canonical ensemble (GCMC) to investigate the role of molecular orientation and surface heterogeneity on the adsorption of N 2 at 77 K. Our research focused on a series of ordered nanoporous materials (SBA-15) with varying degrees of oxygen functionalities. Specifically, we examined the effects of surface heterogeneity on the calculation of pore size distribution (PSD) and the Brunauer-Emmett-Teller (BET) area of porous materials. To provide a comprehensive perspective, we compared our results with three levels of surface oxidation, including a pristine case without any surface oxidation. The results from both our experimental and simulation data reveal the importance of chemical heterogeneity in determining equilibrium properties such as molecular packing within the pores, differential enthalpies of adsorption, and N 2 orientation distribution. Our findings suggest that accurate characterization of surface heterogeneity is crucial for understanding gas adsorption in nanoporous materials and for developing better models for predicting their performance in various applications. Moreover, our simulations revealed substantial changes in the molecular orientation of adsorbate particles with increasing surface heterogeneity. This insight provides valuable information about the behavior of molecules within the nanoporous materials, further enhancing our understanding of the complex adsorption processes in these systems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

This research focuses on developing MIL-53-type compounds with Fe obtained with ligands derived from PET waste, followed by the controlled addition of hydrofluoric acid (HF). Incorporating HF into the MOF structure induced substantial changes in the material textural properties, resulting in a significant change in CO 2 adsorption. Furthermore, a distinctive structural alteration (breathing effect) was observed in the CO 2 isotherms at different temperatures; these structural changes have not been observed by X-ray diffraction (XRD) because this characterization has been performed at room temperature, whereas the adsorption experiments were conducted at 260, 273, and 303 K and different pressures. Subsequently, DFT studies were performed to investigate the CO 2 -filling mechanisms and elucidate the material respiration effect. This approach offers promising opportunities for sustainable materials with improved gas adsorption properties., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Herein, ordered mesoporous materials like SBA-15 and Al/SBA-15 were prepared using the pH adjustment method. Thus, these materials were developed in different pH of synthesis, from the pH adjustment method using a KCl/HCl solution and varying the Si/Al molar ratio (5, 25, and 75). All the ordered mesoporous materials were characterized by FRX, 27 Al NMR, SEM, XRD, N 2 adsorption/desorption, and CO 2 adsorption. From the applied method, it was possible to obtain SBA-15 and Al/SBA-15 with high mesoscopic ordering based on the XRD patterns, independent of the pH employed. From the chemical composition, the insertion of higher amounts of Al into the synthesis caused a progressive improvement in the structural and textural properties of the ordered mesoporous materials. Thus, the chosen synthesis conditions can lead to different aluminum coordination (tetrahedral and octahedral), which gives these materials a greater potential to be applied. The presence of Al in high amounts provides material with the ability to form micropores. Finally, the proposed method proved to be innovative; low-cost; less aggressive to the environment, with efficient insertion of aluminum in the framework of SBA-15 mesoporous material; and practical, based on only one step.

This work presents a ceramic monolith with a honeycomb structure obtained from a natural zeolite (clinoptilolite), bentonite, and alumina. The monolith obtained by extrusion had a cell density of 57 CPSI (cells per square inch), an open frontal area of 52% w/w, and a wall thickness of 0.9 mm. The raw materials and the natural zeolite ceramic monolith (NZCM) were characterized by X-ray diffraction, N 2 adsorption-desorption at 77 K, CO 2 adsorption at 273 K, mercury intrusion-extrusion, axial compression tests, resistance to leaching at acidic and basic pH, and point of zero charge. The NZCM presented an S BET = 31 m 2 ∙g -1 , a modal micropore size of 0.44 nm, a porosity of 39%, the compressive stress = 14 MPa, and a pH PZC = 7.5. The NZCM was used as an inexpensive and easy-to-handle adsorbent to remove methylene blue (MB) dye in batch studies of kinetics and adsorption isotherms. From modeling of adsorption kinetic data, the predominant phenomenon in this system was physisorption. The modeling of adsorption isotherm data shows that the material has homogeneous active sites. The adsorption occurs by monolayer formation, finding a maximum capacity removal rate of 27 mg MB per gram of NZCM. Compared to other structured materials, a high capacity for removing MB with the ceramic monolith was obtained along with good mechanical properties and resistance in acidic and alkaline environments., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Mordenite is a well-known zeolite widely used for industrial processes. However, its pore architecture can be inconvenient due to diffusional issues. A study of the synthesis parameters from an organic-free dense gel was carried out to control the crystal morphology, which resulted in finned mordenite zeolite particles. The obtained materials were characterized by XRD, FTIR, 29 Si and 27 Al MAS-NMR, elemental analysis, nitrogen physisorption, SEM, and TEM. We found that careful manipulation of the hydrothermal parameters directly affected the sizes and morphologies of the crystallites and particles, as well as the textural properties of the final products. Additionally, it was found that mordenite could exhibit a fin morphology with additional mesoporosity, which is a promising means to reduce the diffusional problems of one-dimensional-channel zeolites.

The mixture containing alloy and oxide with iron-based phases has shown interesting properties compared to the isolated species and the synergy between the phases has shown positive effect on dye adsorption. This paper describes the synthesis of Fe 2 SiO 4 -Fe 7 Co 3 -based nanocomposite dispersed in Santa Barbara Amorphous (SBA)-15 and its application in dye adsorption followed by magnetic separation. Thus, it was studied the variation of reduction temperature and amount of hydrogen used in synthesis and the effect of these parameters on the physicochemical properties of the iron and cobalt based oxide/alloy mixture, as well as the methylene blue adsorption capacity. The XRD and Mössbauer results, along with the temperature-programmed reduction (TPR) profiles, confirmed the formation of Fe 2 SiO 4 -Fe 7 Co 3 -based nanocomposites. Low-angle XRD, N 2 isotherms, and TEM images show the formation of the SBA-15 based mesoporous support with a high surface area (640 m 2 /g). Adsorption tests confirmed that the material reduced at 700 °C using 2% of H 2 presented the highest adsorption capacity (49 mg/g). The nanocomposites can be easily separated from the dispersion by applying an external magnetic field. The interaction between the dye and the nanocomposite occurs mainly by π-π interactions and the mixture of the Fe 2 SiO 4 and Fe 7 Co 3 leads to a synergistic effect, which favor the adsorption.

The need for greener procedures is a fact to reduce residues, to decrease industrial costs, and to accomplish the environmental agreements. In an attempt to address this question, we propose the addition of a natural resource, Brazilian diatomite, to an MFI zeolite traditional synthesis. We have characterized the resulting product with different techniques, such as X-ray diffraction, microscopy, and gas sorption, and, afterwards, we evaluate the greenness of the process by the Green Star method. The results were promising: We obtained the desired topology in the form of small crystallites aggregated and a pore diameter of 0.8 nm. In conclusion, the product has the necessary characteristics for an adsorption or catalytic future tests and escalation to industrial production.

The chemistry between layered MWW zeolite and carbon black pearls (BP 2000) as an inexpensive hard template was investigated to develop a rational one-pot synthesis of MCM-22 microspheres. The characterization results showed that the insertion of BP 2000 in the gel synthesis did not substantially compromise the crystallinity and microporosity, and the microscopic analyses showed that BP 2000 played a key role in controlling the final morphology of the MCM-22 zeolite, creating beautiful dandelion-like microspherical particles. The morphology obtained is due to the tortuous shape of the hard template, the particular MWW particle crystals, the interaction with the external surface of the MWW zeolitic precursor, and the synthesis conditions. The stacking of MWW crystals with edge-to-face orientations generates meso-/macrovoids, allowing access to the interiors of the microspheres. The microspheres were homogeneous with sizes ranging from 6 to 8 μm with an increase of the external surface and a macroporous size distribution centered at 200 nm, which is two times that of the traditional MCM-22 zeolite., Competing Interests: The authors declare no competing financial interest.

We report a microfluidic electrochemical immunosensor for Xanthomonas arboricola (XA) determination, based on the covalently immobilization of monoclonal anti-XA antibody (anti-XA) on a previously amino functionalized SBA-15 in situ synthesized in the central channel of a glass-poly(dimethylsiloxane) microfluidic immunosensor. The synthetized amino-SBA-15 was characterized by N 2 adsorption-desorption isotherm, scanning electron microscopy and infrared spectroscopy. XA was detected by a direct sandwich immunoassay through an alkaline phosphatase (AP) enzyme-labeled anti-XA conjugate. Later, the substrate p-aminophenyl phosphate was converted to p-aminophenol by AP. The enzymatic product was detected at +100mV on a sputtered gold electrode. The measured current was directly proportional to the level of XA in walnut trees samples. The linear range was from 5 × 10 2 to 1 × 10 4 CFUmL -1 . The detection limit was 1.5 × 10 2 CFUmL -1 , and the within- and between-assay coefficients of variation were below 5%. Microfluidic immunosensor is a very promising tool for the early and in situ diagnosis of XA in walnuts avoiding serious economic losses., (Copyright © 2017 Elsevier B.V. All rights reserved.)

We report a hybrid glass-poly (dimethylsiloxane) microfluidic immunosensor for epidermal growth factor receptor (EGFR) determination, based on the covalent immobilization of anti-EGFR antibody (anti-EGFR) on amino-functionalized mesoporous silica (AMS) retained in the central channel of a microfluidic device. The synthetized AMS was characterized by N 2 adsorption-desorption isotherm, scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and infrared spectroscopy. The cancer biomarker was quantified in human serum samples by a direct sandwich immunoassay measuring through a horseradish peroxidase-conjugated anti-EGFR. The enzymatic product was detected at -100 mV by amperometry on a sputtering gold electrode, modified with an ordered mesoporous carbon (CMK-3) in a matrix of poly-acrylamide-co-methacrylate of dihydrolipoic acid (poly(AC-co-MDHLA)) through in situ copolymerization. CMK-3/poly(AC-co-MDHLA)/gold was characterized by cyclic voltammetry, EDS and SEM. The measured current was directly proportional to the level of EGFR in human serum samples. The linear range was from 0.01 ng mL -1 to 50 ng mL -1 . The detection limit was 3.03 pg mL -1 , and the within- and between-assay coefficients of variation were below 5.20%. The microfluidic immunosensor is a very promising device for the diagnosis of several kinds of epithelial origin carcinomas., (Copyright © 2017. Published by Elsevier B.V.)