Adsorption Desorption Isotherm Analysis Research Articles

Introducing a novel Hierarchy-Connectivity factor for characterizing micro-mesoporous materials

To provide a comprehensive description of hierarchical pore networks and optimize micro-mesoporous materials, it is essential to consider pore connectivity as a parameter. This study introduces an innovative hierarchy-connectivity factor (HCF) that includes the volume, size, and connectivity data of pores within the pore network. This study covers micro-mesoporous biosourced carbons, with ordered or disordered mesoporous structures, and three commercial activated carbons derived from petroleum coke and biomass. A dual-shape slit-cylinder model was employed to precisely assess the textural properties of these carbons. The proposed methodology evaluates connectivity exclusively through gas adsorption–desorption isotherm analysis, providing a rapid and practical tool for characterizing the porous network of carbon materials. The efficacy of this HCF is demonstrated in the examination of carbon materials functioning as electrodes for supercapacitors. Overall, this research transcends the field of gas adsorption-based studies, highlighting the importance of evaluating the pore network connectivity within carbon materials in order to optimize them for a particular application. Importantly, this contribution could be extended beyond the scope of carbon materials, encompassing a broader spectrum of porous materials.

Visible Light-Driven Photocatalytic CH4 Production from an Acetic Acid Solution with Cetyltrimethylammonium Bromide-Assisted ZnIn2S4

Photocatalytic methods have been popular in energy production and environmental remediation. Designing high-efficiency photocatalysts is still challenging in converting solar energy into chemical fuels. Herein, a series of surfactant-assisted ZnIn2S4 (ZIS) photocatalysts were synthesized by utilizing the one-pot hydrothermal method. Photocatalytic methane production from an acetic acid solution was carried out under LED light (450 nm) irradiation, and the evolved gas was analyzed by the GC-FID system. Reaction factors (surfactant amount, catalyst dose, reaction temperature, substrate concentration, and reaction pH) were optimized for photocatalytic production. With the increase in cetyltrimethylammonium bromide (CTAB) amount, CH4 production gradually increased. The ZIS-3.75 photocatalyst exhibited the highest photocatalytic CH4 production rate (0.102 µmol g−1·h−1), which was approximately 1.8 times better than that of pure ZIS (0.058 µmol g−1·h−1). The presence of CTAB reduced the charge transfer resistance and improved photocurrent response efficiency. Structure and morphology were characterized by XRD, FTIR, SEM, TEM, and N2 adsorption–desorption isotherm analysis. Optical properties were investigated by UV-DRS and PL spectroscopic techniques. The electrochemical evaluation was measured through EIS, Mott–Schottky, and transient photocurrent response analysis. The CTAB-modified catalyst showed excellent stability and reusability, even after five irradiation cycles. Methane production was enhanced by lowering the photogenerated charge transfer resistance and boosting the dispersion of ZIS-3.75 under visible light (450 nm) irradiation.

Industrial dye absorption and elimination from aqueous solutions through bio-composite construction of an organic framework encased in food-grade algae and alginate: Adsorption isotherm, kinetics, thermodynamics, and optimization by Box–Behnken design

A potential bio-adsorbent material for removing Rhodamine B (RB) from aqueous solution is Ru-MOF@FGA/CA beads. The adsorption capability of the material is probably enhanced by the use of a natural substance made of food-grade algae (FGA) and calcium alginate (CA), which has been cross-linked and loaded with ruthenium metal-organic frameworks (Ru-MOF). The Ru-MOF@FGA/CA beads were analyzed by XPS, PXRD, FT-IR, and SEM. The nitrogen adsorption-desorption isotherm analysis of the Ru-MOF@FGA/CA beads before and after the adsorption of RB revealed that had a surface area of 682 m2/g, a pore size of 2.92 nm, and a pore volume of 1.62 cc/g, that decreased after adsorption as the surface area reduced to 468.62 m2/g, while the pore volume reduced to 0.76 cc/g. indicating that the RB molecules occupied the available space within the pores of the material. The decrease in both surface area and pore volume specifies that the Ru-MOF@FGA/CA beads' pores were able to effectively adsorb the RB molecules. The adsorption of RB against the Ru-MOF@FGA/CA beads is affected by pH, adsorbent dose, starting RB concentration, and salinity. Controlling these factors can enhance the adsorption capability and effectiveness of the beads for RB removal. With an adsorption energy of 22.6 kJ/mol, the adsorption of RB onto the Ru-MOF@FGA/CA beads was determined to be a chemisorption process, demonstrating a strong bond among the adsorbent and the adsorbate. The pseudo-second-order kinetics and Langmuir isotherms were used to suit the adsorption process. Because the adsorption procedure was endothermic, it increased as the temperature increased. By using this information, the adsorption conditions may be improved, and the beads' ability to absorb RB can be increased. Up to six reuses of the Ru-MOF@FGA/CA beads are possible without affecting their chemical makeup and maintaining analogous PXRD and FT-IR data after each reuse. The adsorption process can be optimized through the application of the Box–Behnken design (BBD) approach and may entail H-bonding, electrostatic forces, n-π stacking, and pore filling. The exceptional stability of the beads makes them useful for creating long-lasting and efficient adsorbents that remove contaminants from water.

Effect of polypyrrole-derived N-doped carbon coating on the sodium storage properties of NiCo2S4 synthesized by recycling discarded mobile phone batteries

NiCo2S4 with a spherical spinel structure was innovatively synthesized from discarded mobile phone batteries using a simple hydrothermal method, and the surface was coated with N-doped carbon to form NiCo2S4@NC. The products were used as anode materials of sodium-ion batteries to study the effect of the N-doped carbon layer on the electrochemical properties, structure and morphology. The results of XRD, FESEM and TEM revealed that the N-doped carbon layer derived by carbonizing polypyrrole had a minimal effect on the structure and morphology of NiCo2S4, but was coated on the surface of NiCo2S4 with different thicknesses to adjust the electrochemical performance. The presence of N-doped carbon in NiCo2S4@NC was confirmed by Raman spectroscopy. The mesoporous structure of NiCo2S4 and NiCo2S4@NC was corroborated by N2 adsorption-desorption isotherm analysis, and the optimal specific surface area and pore size were 23.14 cm2/g and 18.0 nm, respectively. X-ray photoelectron spectroscopy indicated that Co2+/Co3+ and Ni2+/Ni3+ coexist in the spinel NiCo2S4@NC50 synthesized upon adding 50 μL of pyrrole monomer. NiCo2S4@NC50 outperformed other products in terms of its electrochemical properties, where its initial discharge specific capacity under the current density of 0.1 A g−1 was 1099.6 mA h g−1 and the specific capacity following 100 cycles reached 327.5 mA h g−1. NiCo2S4@NC50 exhibited an optimal electrochemical performance and demonstrated a competent approach toward recycling discarded mobile phone batteries and building electrodes with high performance for use in energy equipment.

Enhancing photocatalytic efficiency with Mn-doped ZnO composite carbon nanofibers for organic dye degradation

<abstract> <p>In this study, Mn-doped ZnO composite carbon nanofibers (Mn-ZnO/CNFs) were prepared via a simple blending and electrospinning (ES) method, followed by a thermal treatment. These fibers were used to investigate the photocatalytic degradation of an organic dye under UV and visible light irradiation. The results showed that Mn-ZnO/CNFs were successfully prepared under the same conditions used for CNFs preparation conditions, which induced a morphological change from a smooth to a rough surface compared to the CNFs. Energy dispersive X-ray (EDX), x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS) analyses confirmed the formation of Mn-doped ZnO on the CNFs' surface. Furthermore, the addition of the catalyst significantly increased in the specific surface area, and a N<sub>2</sub> adsorption-desorption isotherm analysis revealed that all samples had mesoporous characteristics with a type IV isotherm index. The photocatalytic activity of the Mn-ZnO/CNFs carbonized at 650 ℃ using methylene blue (MB) dye as a model pollutant was investigated. All prepared samples effectively removed the MB with a degradation rate of 70-90%. The kinetic reaction rate was described using the simplified Langmuir-Hinshelwood equation. Overall, the CNFs and composites nanofibers developed through moderate thermal treatment processes possessed a high specific surface area and oxygen vacancy, enabling their potential use as adsorbents and as a catalyst support for reactions at room-to-elevated temperatures, as well as photocatalysts for the removal of organic contaminants.</p> </abstract>

Optimization Conditions of Malachite Green Adsorption onto Almond Shell Carbon Waste Using Process Design.

Almond shell-based biocarbon is a cheap adsorbent for the removal of malachite green, which has been investigated in this work. FT-IR, DRX, and BET were used to characterize almond shell-based biocarbon. The nitrogen adsorption-desorption isotherms analysis results showed a surface area of 120.21 m2/g and a type H4 adsorption isotherm. The parameters of initial dye concentration (5-600 mg.L-1), adsorbent mass (0.1-0.6 mg), and temperature (298-373 K) of adsorption were investigated. The experiments showed that the almond shell could be used in a wide concentration and temperature range. The adsorption study was fitted to the Langmuir isotherm and the pseudo-second-order kinetic model. The results of the FT-IR analysis demonstrated strong agreement with the pseudo-second-order chemisorption process description. The maximum adsorption capacity was calculated from the Langmuir isotherm and evaluated to be 166.66 mg.g-1. The positive ∆H (12.19 J.mol-1) indicates that the adsorption process is endothermic. Almond shell was found to be a stable adsorbent. Three different statistical design sets of experiments were taken out to determine the best conditions for the batch adsorption process. The optimal conditions for MG uptake were found to be adsorbent mass (m = 0.1 g), initial dye concentration (C0 = 600 mg.L-1), and temperature (T = 25 °C). The analysis using the D-optimal design showed that the model obtained was important and significant, with an R2 of 0.998.

Investigating the impact of structural defects in MWCNT/MnFe2O4 nanocomposite for efficient photodegradation of cationic dye

The co-precipitation hydrothermal method was used to prepare MWCNT (0.01g and 0.04g)/MnFe2O4 composites and the valence state elemental compositions were verified with XPS. The TEM micrograph revealed that the functionalized MWCNTs were well-dispersed in the matrix and retained their tubular structure. PL analysis indicates an increase in electron-hole pair separation, electron trapping in the MWCNT and an increase in structural defects. The result of positron annihilation lifetime spectroscopy (PALS) reveals that the concentration of composite surface defect increases with CNT. Additionally, these findings show that the vacancy clusters and voids are more prominent in the interface of the MWCNT/MnFe2O4 composite compared to the MnFe2O4 particle surface. N2 adsorption-desorption isotherms analysis confirmed the surface area change in the composite. Notably, the MWCNT/MnFe2O4 composite exhibited significantly enhanced photocatalytic activity compared to pure MnFe2O4, leading to superior efficiency in the removal of methylene blue (MB).

Synthesis of novel Cu2WS4/Bi2WO6 heterojunctions and evaluation of their photocatalytic activity for removal of tetracycline under visible light irradiation

In order to change the photocatalytic performance of bismuth tungstate monomer material, the Z-type heterojunction Cu2WS4/Bi2WO6 (CWS/BW) system was formed by loading Cu2WS4 on Bismuth tungstate by hydrothermal method, and then characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). It was concluded that the crystallinity of Cu2WS4/Bi2WO6 system varied with the change of the composite ratio, and no impurity influence was found. The morphology of Cu2WS4/Bi2WO6 system reflects the flower bulbous formed by the superposition of Cu2WS4 nanosheets and Bi2WO6 nanosheets. The overall analysis shows that Cu2WS4 and Bi2WO6 were successfully compounded. Through the characterization analysis of ultraviolet–visible diffuse reflectance absorption spectra (UV–Vis DRS), photoluminescence spectrogram (PL) and N2 adsorption-desorption isotherm analysis (BET), it was concluded that the Cu2WS4/Bi2WO6 system had a higher specific surface area, a wider light corresponding range and a lower photogenerated electron-hole recombination rate.Experiments show that the 5-CWS/BW in the Cu2WS4/Bi2WO6 system had the strongest photocatalytic effect under visible light, and the light degradation rate in 100min can reach 80%, which is 1.7 times and 3.2 times that of monomer Bi2WO6 and Cu2WS4, respectively. 5-CWS/BW still had high activity under different experimental conditions. Later, cyclic experiments proved that the material had strong stability. Finally, the main active substances in photocatalysis were clarified through free radical capture experiments and electron spin resonance (ESR) technology, and the photocatalytic mechanism of Cu2WS4/Bi2WO6 system was inferred.

Synthesis of Chitosan/Halloysite Nanotubes Composite Aerogel as Adsorbents

A novel chitosan/halloysite nanotubes composite aerogel (CS/HNTs) was prepared by incorporation of halloysite nantubes into crosslinked chitosan network via vacuum freeze drying. Nitrogen adsorption—desorption isotherms analysis show it has a specific surface area of 51.24 m2g–1 with an average pore diameter of 8.96 nm, the resulting CS/HNTs was used as an efficient adsorbent material for removal of Cr(VI) from water. The adsorption performance of CS/HNTs for Cr(VI) under different experimental conditions were studied. The adsorption experiments show that the adsorption capacity of CS/HNTs composite aerogel for Cr(VI) increases slightly with the increase of temperature and the optimum pH value for Cr(VI) adsorption is found at pH = 2. The maximum adsorption capacity of Cr(VI) was estimated to be 49.85 mg g–1 with the optimum adsorbent dose of 0.10 g at 30 °C. The adsorption kinetics of the assay exhibit a strong correlation with the mathematical model known as the pseudo—second—order equation. The experimental results exhibit a high level of conformity with the Langmuir isotherm, providing evidence of a state of equilibrium. Moreover, detailed computations have been conducted to ascertain crucial thermodynamic parameters such as the change in Gibbs free energy (ΔG°), modification in enthalpy (ΔH°), and variation in entropy (ΔS°). These calculated parameters provide compelling evidence that the adsorption of Cr(VI) onto CS/HNTs is a spontaneous process driven by thermodynamic favorability. Furthermore, the process is characterized by the absorption of heat from the surroundings, indicating an endothermic nature.

Building nickel tungstate nanospheres anchored polyaniline conductive matrixes for trace level electrochemical determination of theobromine in food samples

In this work, a nickel tungstate nanospheres-anchored polyaniline nanocomposite (NiWO4/PANI) was prepared by using a hydrothermal route followed by a chemical oxidative polymerization route and explored as an electrode material for the determination of theobromine (TB). The X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis confirm the structural-compositional details of NiWO4/PANI nanocomposite. Further, the successful fabrication of NiWO4 nanospheres perfectly anchoring on the conductive matrix of PANI is revealed by transmission electron microscope (TEM) analysis. The N2 adsorption-desorption isotherm analysis revealed the specific surface area of the composite is 28.49 m2/g. Due to the feasible multiple electroactive sites and the synergistic effect between NiWO4 and conductive PANI matrix in the NiWO4/PANI nanocomposite, it enables rapid electron migration and possesses high electrical conductivity during the sensing performances. From the amperometric i-t method, NiWO4/PANI sensor exhibits a wide linear range (0.05–1350.6 μM) and a low detection limit (0.0079 µM). Besides, NiWO4/PANI based sensor shows excellent stability, anti-interference ability and reproducibility, suggesting NiWO4/PANI composite-modified sensors could be a potential candidate for determining TB in food samples with suitable recovery ranges.

Architecture of hybrid electrode by the composition of CoMoO4 /rGO/PANI for asymmetric supercapacitors

The enormous developments in the area of smart and wearable technology have led to grow interest in innovative and portable energy storage devices. This study described the development and electrochemical behavior of asymmetric supercapacitors with a negative electrode of activated-carbon (AC) and positive electrode of cobalt-molybdate/reduced graphene-oxide/polyaniline (CoMoO4 /rGO/PANI). The positive electrode materials of CoMoO4 /rGO/PANI were synthesized using a facile hydrothermal approach. The nanocomposites were characterized using physico-chemical methods including nitrogen adsorption-desorption isotherm analysis, X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), X-ray Photon Spectroscopy (XPS) and Raman spectroscopy. The CoMoO4/rGO/PANI nanocomposite showed a noticeable specific capacity of 630 C g−1 when tested with three electrodes in 3 M alkaline solution (KOH). The CoMoO4 /rGO/PANI //AC asymmetric device demonstrated the optimal specific capacitance of 350 C g−1 with an energy density of 96 W h kg−1 with current density of 1.4 A g−1. The assembled device demonstrated enhanced cyclic stability with outstanding capacitance retention of nearly 97 % after 10,000 cycles (at 51 mA cm2 areal-current density). This composite electrode has a lot of promise for usage in wearable technology, flexible electronics, and technological gadgets.

Synthesis of quercetin-iron (Fe) complex and its in silico and in vitro confirmation towards antibacterial activity.

Aim: In this study quercetin-iron complex (QFC) was synthesized and the structural characterizations such as x-ray diffraction, field emission-scanning electron microscopy, energy-dispersive x-ray and Brunner-Emmitt-Teller adsorption-desorption isotherm analysis revealed the crystallinity state, surface morphology and nature of the adsorbing surface with surface area value. Methodology: Functional characterizations such as UV-visible spectrometric and Fourier transform infrared analysis collectively indicated the chemical changes that appeared after complex formation in terms of characteristic change in the spectrum and band position, respectively. Results: The in vitro antibacterial activity against Escherichia coli and Staphylococcus aureus has shown a dose-dependent decrease in colony count and achieved significant removal at 15 mg/ml concentration of QFC. Conclusion: The molecular docking study supports the therapeutic application of QFC.

Determination of Benzimidazoles in Chicken and Egg Samples by Urea-Based Covalent Organic Polymer (UCOP) Pipette Tip–Solid-Phase Extraction (PT–SPE) and High-Performance Liquid Chromatography–Tandem Mass Spectrometry (HPLC–MS)

A urea-based covalent organic polymer (UCOP), was synthesized using 1,4-phenylene diisocyanate (PPDI) and 4,4′,4″-(1,3,5-triazine-2,4,6-triyl) trianiline (TTTA) and characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and nitrogen adsorption-desorption isotherm analysis. The prepared material was employed as an adsorbent for pipette tip–solid-phase extraction (PT–SPE) for benzimidazoles before high-performance liquid chromatography–tandem mass spectrometry analysis (HPLC–MS). The parameters affecting the isolation efficiency, including salt concentration, sample pH, mass of adsorbent, and types and volumes of eluent, were optimized. Using these conditions, PT–SPE provided good linearity from 0.1 to 10 μg kg−1 with low limits of detections (LODs) of 0.02 μg kg−1 together with good precision (relative standard deviations from 4.2 to 8.3%) and accuracy (recoveries from 76.2 to 84.8%). The results demonstrate that the urea-based covalent organic polymer has the potential for the enrichment of trace benzimidazoles.

Imine-Decorated Copper-Based Metal-Organic Framework for the Photodegradation of Methylene Blue.

A low cost imine-decorated linker, 4,4'-(hydrazine-1,2-diylidenedimethylylidene)dibenzoic acid was utilized for the preparation of copper-based metal-organic framework (MOF) denoted as Cu-L via a solvothermal technique. The synthesized MOF material has been fully characterized by different analytical techniques such as Fourier-transform infrared (FT-IR) spectroscopy, powder X-Ray diffraction (PXRD), scanning electron microscopy (SEM), energy dispersive X-Ray spectroscopy (EDX), nitrogen adsorption-desorption isotherm analysis, and thermogravimetric analysis (TGA). It has been found that the coordination of Cu2+ with L considerably reduced the band gap of the L of nearly about 1eV, which is approximately 26% decline in total. Notably, a narrow band gap of the photocatalyst is an essential requirement for the proficient photodegradation of organic contaminants. An excellent optical properties and narrow band gap of (2.8eV) of Cu-L ensure their suitability as a photocatalyst for the degradation of methylene blue (MB) dye. In the presence of Cu-L photocatalyst, 84.22% degradation of MB dye was observed after 150min under sunlight exposure. It is the first time that imine-functionalized MOF was utilized for the degradation of MB dye under sunlight irradiation. For understanding the photodegradation of MB dye by the Cu-L photocatalyst, all the plausible mechanistic studies have been carried out in detail. Both theoretical (with the help of density functional theory (DFT) calculations) as well as experimental studies have been conducted to justify the possible mechanisms for the photodegradation of MB dye by Cu-L. The current work may open a new opportunity to construct a cheap MOF-based photocatalysts for fast degradation of dye contaminants.

CO2 capture by microporous carbon based on Brazil nut shells.

The increase in burning, deforestation, and the exorbitant use of fossil fuels have contributed to the increase in carbon dioxide emissions; this gas is responsible for the intensification of the greenhouse effect and radical climate changes. In this way, it becomes necessary to find alternatives to reduce its emission. Porous carbon materials synthesized from lignocellulosic waste can be employed in technologies for capture and utilization of CO2 due to the advantages such as selectivity, low-cost synthesis, high surface area and pore volume, and thermal and chemical stability. Considering the availability of Brazil nut biomass residues in the Amazon region, this article proposes to synthesize activated carbon from the lignocellulosic residue using physical and chemical activation methods for CO2 capture. The analysis of N2 adsorption-desorption isotherms proves the predominance of a microporous structure when using the two synthesis methods described here. In physical activation, the surface area was 912 m2/g, while, in chemical activation, it was 1421 to 2730 m2/g. The sample treated via the chemical method (BS6-K1) showed better performance in CO2 adsorption, with adsorption results of 3.8 and 6mmol/g of CO2 at 25 ℃ and 0°C, respectively, at 101kPa. CO2 adsorption capacity is due to the high volume of ultramicropores. It is believed that the microporous carbon material synthesized from Brazil nut residues is an alternative precursor for carbon materials used as CO2 capture.

Polyester fabric-based nano copper-polyhedral oligomeric silsesquioxanes sorbent for thin film extraction of non-steroidal anti-inflammatory drugs

In this study, in-situ preparation of copper nanoparticles under sonoheating conditions followed by coating on commercial polyester fabric is reported. Through the self-assembly interaction of thiol groups and copper nanoparticles, the modified polyhedral oligomeric silsesquioxanes (POSS) was deposited on the fabric's surface. In the next step, radical thiol–ene click reactions were implemented to create more layers of POSSs. Subsequently, the modified fabric was applied for sorptive thin film extraction of non-steroidal anti-inflammatory drugs (NSAIDs) including naproxen, ibuprofen, diclofenac, and mefenamic acid from urine samples, followed by high-performance liquid chromatography equipped with a UV detector. The morphology of the prepared fabric phase was characterized by scanning electron microscopy, water angle contact, energy dispersive spectrometry mapping, analysis of nitrogen adsorption-desorption isotherms, and attenuated total reflectance Fourier transform infrared spectroscopy. The significant extraction parameters, including the acidity of the sample solution, desorption solvent and its volume, extraction time, and desorption time, were investigated using the one-variable-at-a-time approach. Under the optimal condition, NSAIDs' detection limit was 0.3–1 ng mL−1 with a wide linear range of 1–1000 ng mL−1. The recovery values were between 94.0% and 110.0%, with relative standard deviations of less than 6.3%. The prepared fabric phase exhibited acceptable repeatability, stability, and sorption property toward NSAIDs in urine samples.

Kinetics of caffeine adsorption from aqueous solutions on active charcoal AC-0-9

The process of the kinetics of caffeine adsorption from aqueous solutions on activated carbon AC-0-9, obtained from apple wood, was studied. Analysis of nitrogen adsorption-desorption isotherms demonstrated that this carbon adsorbent is basically mesoporous. The pseudo-two model describes best the kinetic process, highlighting the role of functional groups on the activated carbon surface. The pseudo-one model only initially describes the kinetic process of caffeine adsorption on this activated carbon. It was found that the kinetics ofthe adsorption process of caffeine on AC-0-9 activated carbon takes place in two stages. In the first stage, the speed of intraparticle diffusion is high, due to the adsorption of caffeine molecules in macroand mesopores, and in the second stage, the speed of intraparticle diffusion is low, given the fact that adsorption occurs in micro- and supermicropores.

Unleashing the catalytic potency of nanoporous copper oxide particles derived from copper 5-nitroisophthalate MOF towards the multicomponent synthesis of 2,3-dihydroquinazolinones

Recent years have witnessed noteworthy advancements in the designing of MOFs and their derived materials. The present work for the very first time reports the successful fabrication of a series of CuO nanoparticles (NPs) by the controlled pyrolysis of Cu-5-nitroisophthalate (Cu-NIPA) metal organic framework (MOF) and employed it further as a catalytic entity for accessing 2,3-dihydroquinazolinone moieties. The systematically designed CuO nanoarchitectures were synthesized in a single step through pyrolysis of Cu-5-NIPA in air atmosphere and analytically affirmed using a multitude of advanced physico-chemical characterization tools such as Fourier transform infrared (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), N2 adsorption-desorption isotherm, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis. The catalytic potential of the developed CuO nanoarchitectures was subsequently evaluated in the one-pot multicomponent coupling of aromatic aldehyde, isatoic anhydride, alkyl/aryl amine to produce 2,3-dihydroquinazolinone scaffolds (up to 97% yield). Furthermore, a proposed catalytic mechanism for the concerned reaction has also been provided. Some of the additional startling attributes of the developed methodology include excellent product yield in short duration, easy work-up procedure, green reaction solvent, ambient reaction parameters, wide substrate scope, high turnover number and good recyclability for multiple runs.

Hierarchical meso-micro porous Fe[sbnd]N[sbnd]C derived from tripolycyanamide-based microporous polymer as efficient electrocatalyst for oxygen reduction reaction

Designing porous FeNC nanomaterials with highly efficient active sites is an effective strategy for constructing high-performance oxygen reduction reaction (ORR) electrocatalysts. N-containing porous organic polymers (POPs) have emerged as promising candidates for the preparation of porous FeNC catalysts. Here, N-rich tripolycyanamide-based microporous polymer (TCAMP)-coated SiO2 nanospheres (SiO2@TACMP) were prepared as the precursors of an Fe-N doped hierarchical meso-micro porous carbon (Fe-N-HMC) electrocatalyst for the ORR. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) characterizations demonstrated that the Fe-N-HMC catalyst possessed a higher content percentage of Fe-Nx active sites and a better distribution of Fe nanoparticles than its Fe-N doped microporous carbon (Fe-N-MC) counterpart. N2 adsorption–desorption isotherm analysis showed that Fe-N-HMC catalyst exhibited a hierarchical meso-micro porous system, with a Brunauer-Emmett-Teller (BET) surface area (SBET) of 733 m2 g−1 (∼2 times of Fe-N-MC’s SBET). As a result, Fe-N-HMC catalyst presented a highly efficient ORR performance with a half-wave potential of 0.856 mV, which is similar to the commercial grade 20 wt% Pt/C catalyst and superior to the Fe-N-MC catalyst. Moreover, the as-synthesized Fe-N-HMC catalyst displayed a better durability and methanol tolerance than the commercial Pt/C catalyst. Therefore, Fe-N-HMC shows great promise as an ORR catalyst for fuel batteries and metal-air cells due to its low-cost, high activity, and good stability.

Vitamin C modified crayfish shells biochar efficiently remove tetracycline from water: A good medicine for water restoration

In this study, crayfish shell biochar (CSB) was modified by introducing vitamin C (VC) with abundant surface functional groups. CSB was impregnated with VC at different ratios and its capacity to adsorb tetracycline (TC) from water was analyzed. The physicochemical properties of CSB were determined by N2 adsorption–desorption isotherm analysis, X-ray diffraction, and Fourier transform infrared spectroscopy. The effects of various factors on adsorption such as the pH, TC concentration, time, and salt ion concentrations were also investigated. Based on the chemical structure of VC, VC can provide CSB with more oxygen-containing functional groups such as hydroxyl groups. The results showed that the CSB modified with VC (CSB-VC) exhibited excellent adsorption of TC, and CSB-VC2 with an impregnation ratio of 2 (gVC/gCSB) had the greatest adsorption performance (saturated adsorption capacity, Qm = 293.36 mg/g), whereas the adsorption performance of CSB alone was about 50% lower (Qm = 172.16 mg/g). The optimal impregnation ratio VC improved the adsorption performance of CSB after modification to 70.4% of the original. Hydrogen bonding, p–p conjugation, pi-pi electron donor–acceptor effect, and π–π interactions were identified as the main adsorption mechanisms. CSB-VC2 was highly effective over a wide range of pH values and at high ion concentrations. Experiments demonstrated the effective regeneration of the adsorbent after multiple cycles, thereby indicating its excellent reusability. It should be noted that the adsorption capacity was good under different water quality conditions, and thus it should exhibit stable adsorption performance under complex water environment conditions.