Journal of Porous Materials最新文献

The search for efficient and more sustainable treatments of wastewater has become increasingly challenging in recent years. Aiming to contribute with this demand, the current study focused on the synthesis of mesoporous silica (MS) bio-adsorbents (MS1, MS2, MS3 and MS4) based on Santa Barbara Amorphous-15 (SBA-15) by a relatively simple and sustainable process using sodium silicate (SS) extracted from rice husk ashes (RHA) and Pluronic P123. Subtle and careful changes in the synthesis conditions resulted in MS samples with ordered pores and high specific surface area (S_BET), that is, 712 m² g⁻¹ (MS1), 838 m² g⁻¹ (MS2), 905 m² g⁻¹ (MS3) and 806 m² g⁻¹ (MS4), which are higher than other silicas also produced from RHA, indicating that our bio-adsorbents may exhibit superior pollutant adsorption capabilities. In that regard, various research reports the potential of MS to adsorb dyes, heavy metals, bacteria, pharmaceuticals and other pollutants in model systems. However, our proposal advanced in testing the adsorbent potential of these materials for two independent systems: (i) removal of methylene blue (MB) model dye from aqueous solutions and (ii) treatment of an industrial denim laundry effluent. Indeed, all MS bio-adsorbents were potentially efficient and reusable, but MS1 and MS2 exhibited higher adsorption capacities for MB dye (q_e = 327.29 and 365.78 mg g⁻¹, respectively) at pH 12.0. The investigation of the effect of ions and DFT calculations contributed to elucidating the interactions between MB dye and MS bio-adsorbents. In addition, our bio-adsorbents stand out by their excellent efficiency (~ 75%) in the remediation of an industrial effluent exclusively by adsorption. Among the produced bio-adsorbents, MS2 has shown a higher degree of mesoscopic order, well-ordered and open-ended pores with oval architecture and interconnected hollow channels, but both MS1 and MS2 displayed similar adsorption capacities normalized by total surface area, demonstrating to be promising and eco-friendly adsorbents for use in environmental remediation.

Betel leaf extract (BLE) is well-known for its anti-bacterial, anti-inflammatory, and anti-oxidant activities as well as wound healing effects. For the first time, the ethanolic BLE has been successfully encapsulated into thermo-sensitive chitosan hydrogels to deliver the extract to infected wounds while preserving its biological activities. Morphologies, sol–gel transition, chemical structure, and pH of the hydrogels are comprehensively studied under the variation in the initial loading BLE concentration. Release kinetics of the hydrogels are evaluated in different environmental conditions to determine the BLE release behavior and the suitable mathematical model. The hydrogels exhibit sol–gel transition at 37.0–40.0 °C, a gelation time of 9.5–13.0 min at 37 °C, a neutral pH, and a hollow structure self-crosslinked by chitosan with both surface and internal adhesion of BLE. The BLE release from the hydrogels is affected by pH, temperature, and the BLE loading concentration and is governed by a controlled diffusion following the Korsmeyer-Peppas model. The hydrogels release 50.91–60.29% of their initial loading content and the release solutions demonstrate potent antibacterial activity against E. coli and S. aureus evidenced by the inhibition rate of 70.67–99.94%. Moreover, the chitosan hydrogels encapsulating BLE are biodegradable with a remarkably high degradability of 76.92–79.74% after 14 days of exposure to lysozyme under simulated physiological conditions. Based on the findings, the developed hydrogels are considered a potential delivery system to handle open skin wounds via local subcutaneous injection.

UiO-66 specimens having different acetic acid/ZrCl₄ molar ratios were prepared and pyrolyzed to ZrO₂ as supports for Pt and Ni, intended to catalyze the decarboxylation of oleic acid. Brunauer-Emmett-Teller surface area analyses, NH₃ temperature-programmed desorption and pyridine adsorption infrared spectroscopy showed that the material made using an acetic acid/ZrCl₄ molar ratio of 100 (ZrO₂-100) had the largest specific surface area, acid amount and acid strength values. The yield of C₈-C₁₇ alkanes obtained from Ni/ZrO₂-100 exceeded that provided by Pt/ZrO₂-100 because the latter possessed more acidic sites than the former, which excessively cracked long-chain hydrocarbons. The 1 wt% Ni/ZrO₂-100 catalyst showed the best catalytic performance, with 96.4% conversion of oleic acid and an 80.6% yield of C₈-C₁₇ alkanes after 4 h at 340 °C under a CO₂ atmosphere at a pressure of 18 bar. The conversion of oleic acid remained almost unchanged after 4 reuses of this catalyst whereas the yield of C₈-C₁₇ alkanes decreased to 66.7%. This result is attributed to a loss of acidic sites and an increase in carbon build-up.

This research explores humidity sensing of 3-D mesoporous SnO₂, presenting a novel approach for addressing the growing demand for advanced nanomaterials in environmental monitoring and remediation. We examined the variations in electrical resistance of mesoporous SnO₂ in response to different humidity levels. Mesoporous SnO₂ was made using MCM-48 as a hard template by nanocasting method and analysed using suitable techniques. The finding indicates the successful replication of the cubic mesoporous structure of MCM-48 using SnO₂. The SnO₂ replica maintains the unique three-dimensional cubic arrangement and the high specific surface area characteristic of MCM-48, with a measured surface area of 823.45 m²/g. Mesoporous SnO₂ humidity sensors exhibit remarkable sensitivity (1180.229 Ω/RH%) attributed to the altered resistance under variety of humidity conditions, which improves the accuracy of moisture measurement. Notably, the sensor shows a linear declination of resistance towards mid-range of relative humidity, indicating high sensitivity. The sensor exhibits a significant resistance shift of 4.5 orders, with a rapid response time of 8.2s and a recovery time of 9.5s. This study emphasizes the versatility of mesoporous SnO₂ and highlights its potential to address current challenges in humidity sensing.

Design of strategies to modify the hydrogen evolution activity of electrocatalysts is vital for the commercial implementation of hydrogen production. Herein, we explore the surface modification of monoclinic WO₃ using itaconic acid (ITA) ligand via a facile hydrothermal synthesis route. Comprehensive XRD, HRTEM, FTIR, and Raman analyses confirmed the formation of (002) oriented monoclinic WO₃ and the successful incorporation of ITA coating on the WO₃ samples. The FESEM images illustrated the randomly coated ITA particles on the smooth nanorods of m-WO₃ nanorods. The ITA-coated m-WO₃ demonstrated an overpotential of 267 mV at 10 mA/cm² current density and exhibited a lower Tafel slope and charge transfer resistance in an acidic electrolyte medium. The carboxylic groups of itaconic acid promote proton transfer, which, along with the highly reactive (002) dominant facets of WO₃, synergistically enhanced the HER activity. The (002) oriented WO₃ sample with the highest mass loading of itaconic acid (0.3 M) resulted in a tenfold increase in surface area, thereby enhancing the accessible active sites. The enhanced porosity and proton transfer properties of the itaconic acid on integration with WO₃ improved their potential as an HER electrocatalyst.

Sulphonic acid functionalized mesoporous SBA-15 (SSA) was synthesized by a one-pot hydrothermal method using P123 as the surfactant in acidic media. The basic framework of the SSA material was assembled through the simultaneous hydrolysis and co-condensation of tetraethylorthosilicate (TEOS) and 3-mercaptopropyltrimethoxysilane (MPTMS) and in situ oxidation of the thiol moieties to sulfonic acid functionalities aided by H₂O₂. Phosphotungstic acid (HPW) was incorporated into the SSA matrix via a simple wet impregnation. Successful immobilization of HPW over SSA without disrupting the mesoporous framework could be established by detailed spectroscopic and microscopic characterization. The potential of HPW/SSA systems in catalyzing the formation of bis(indolyl)methanes under ambient conditions is explored. The remarkable performance under light-assisted conditions and a comparative evaluation with conventional thermal synthesis are demonstrated. The novel protocol offers an excellent yield of BIMs in an aqueous medium in a short reaction time, eliminating the need for organic solvents and complex work-up procedures. Sustainable performance upon recycling and broad substrate scope validate the versatility of the catalyst. This present protocol thus provides an operationally simple, scalable, and versatile method for synthesizing BIMs.

In this research, a modified magnetic nanocomposite based on layered double hydroxide (Fe₃O₄/C/CoFe-LDH) was synthesized through co-precipitation and thermal processes. Modification of the magnetic nanoparticles was carried out by applying a carbon coating. After the surface modification of these nanoparticles, LDH was immobilized on the surface of Fe₃O₄/C. To synthesize CoFe-LDH, a co-precipitation process was performed using cobalt (II) nitrate and iron (III) nitrate. The synthesized nanocomposite was characterized by FT-IR, XRD, SEM, EDS, STA, TEM, VSM and BET. After identifying of Fe₃O₄/C/CoFe-LDH, its catalytic activity in the Hantzsch reaction was evaluated. The investigations exhibited that in the presence of the designed catalyst, the expected products can be produced with a high yield in a very short time. In addition, the recyclability and reusability of the prepared nanocomposite were evaluated. The results of these investigations show that after four cycles, the recycled catalyst still maintains its activity and only causes a slight decrease in the reaction efficiency.

Coating crystal seeds on rough supports with curvature has been a challenge for fabricating zeolite membranes. Here, an adhesion-printing method has been developed to coat platelike MFI crystals on an Al₂O₃ tubular support to prepare MFI zeolite membranes. In this method, a macroporous Al₂O₃ tubular support is firstly enclosed with pressure-sensitive adhesive (PSA). Then a beforehand-prepared platelike MFI crystal layer is adhesion-printed on the PSA coated Al₂O₃ tubular support. An MFI seed layer on the macroporous tubular support is successfully obtained after removing the pressure-sensitive adhesive by calcination. Finally, highly (h0h)-oriented, dense and continuous silicalite-1 membranes are fabricated after a hydrothermal secondary growth in a zeolitic synthesis system, confirmed by XRD and SEM techniques. SEM observations evaluate the effect of TPAOH amount, crystallization temperature and time on the integrity and thickness of the zeolite membranes. Binary separation of butane isomers at an ambient temperature has been performed on the prepared silicalite-1 membranes, achieving a separation factor of 31.7 for an equimolar n-butane /i-butane mixture at a n-butane permeance of 6.03 × 10^− 9 mol·m^− 2·s^− 1·Pa^− 1.

Activated carbon prepared from sawdust, magnetized by magnetite nanoparticles, was used for the adsorption of crystal violet dye (CV) from an aqueous solution. The nanocomposite Fe₃O₄/AC was characterized by means of XRD, FTIR, SEM, and BET analyses, along with size distribution and zeta potential assessments. The pH_PZC and BET surface area of Fe₃O₄/AC were 6.05 and 160 m²/g, respectively. The study identified the optimum pH condition as pH 9.0, with a maximum removal efficiency of 100%. Kinetic studies were conducted, and the data fitted well with the pseudo-second order equation. The synthesized Fe₃O₄/AC exhibits a maximum uptake capacity of 76.0 mg/g. Overall, this nanocomposite provides an effective type of adsorbent for removing CV dye. Its primary advantage lies in its simple synthesis compared to other magnetic materials, along with its economic viability, rapid preparation, and environmental friendliness.

In this study, a metal-organic framework (MOF)-based prodrug was synthesized through a Schiff base reaction between UiO-66-NH₂ and 3,4-dihydroxybenzaldehyde (DHBD) drug, resulting in the formation of DHBD@MOF prodrug containing a pH-sensitive C = N bond. Additionally, a dual pH-responsive drug delivery platform was developed, which encapsulated both 5-Fluorouracil (5-FU) drug and DHBD@MOF prodrug within a hydrogel composed of carboxymethyl cellulose (CMC) and alginate (Alg.). The characteristics were analyzed using PXRD, FT-IR, FE-SEM, TEM, and BET. The release studies demonstrated that the hydrogel effectively protected the platform from burst release in the acidic conditions of the stomach and small intestine. Only 1.31% release of DHBD from DHBD@MOF/5-FU@hydrogel was observed after 2.5 h at pH 1.2, compared to near 90% release from DHBD@MOF prodrug under the same conditions. Upon swelling of the hydrogel in the intestine and colorectum at pH around 6.5–7.4, pH-sensitive C = N bonding of DHBD@MOF was cleaved at acidic colorectal cancer sites, activating the inactive prodrug. Furthermore, the hydrogel facilitated controlled release of DHBD and 5-FU in simulated gastric fluid (SGF) at different pH levels (1.2, 4.5, 7.4, and 6.5). The gradual release of DHBD from hydrogel in the intestine (pH 7.4, 8.5 h) and colorectum (pH 6.5, 24 h) was 10.60% and 41.68%, respectively. This allowed for significant accumulation of the inactive DHBD@MOF prodrug at acidic tumor sites, with 89.40% and 58.32% accessing the tumors after 8.5 h and 24 h, respectively. The findings of this research hold promise for applications in medical science and pharmaceutics after in vivo experiments.