Mesopore Volume Research Articles

Simple and sustainable synthesis of loosely stacked nano-H-ZSM-5 aggregates from kaolin and catalytic studies

The conversion of natural clay to crystalline zeolites has been the subject of considerable interest from both academic and industrial circles. We present an effective strategy for converting kaolin to ZSM-5 zeolite, addressing the issue of reduced mesopore formation in conventional nano-ZSM-5 aggregates due to close-packing. This strategy utilizes kaolin as the sole source of silicon and aluminum, and by decoupling the nucleation and growth of ZSM-5 crystals, loosely stacked nano-H-ZSM-5 aggregates with high crystallinity crystals can be synthesized in a solid-like system by employing a tiny amount of TPAOH (TPAOH/SiO2 = 0.064). The resulting nano-H-ZSM-5 aggregates exhibited high specific surface area (405.66 m2/g), high mesopore volume (0.64 cm3/g), and superior catalytic activity. This strategy offers a novel approach to the cost-effective synthesis of nano-H-ZSM-5 aggregates suitable for industrial applications.

Activated Carbons Derived from Different Parts of Corn Plant and Their Ability to Remove Phenoxyacetic Herbicides from Polluted Water

In this study, the adsorption of phenoxyacetic acid (PAA) and its chlorinated derivatives, including 4-chlorophenoxyacetic acid (4CPA) and 2,4-dichlorophenoxyacetic acid (2,4-D), on activated carbons (ACs) from corn kernels (AC-K), corn leaves (AC-L), and corn silk (AC-S) were investigated. The adsorption kinetics followed the pseudo-second-order model, and the film diffusion was the rate-limiting step. The adsorption rate increased in the order PAA < 4CPA < 2,4-D and was correlated with the porous structure (mesopore volume) of these ACs. The Langmuir isotherm models best fit the experimental data; PAA was adsorbed least and 2,4-D most preferentially. The observed trend (PAA < 4CPA < 2,4-D) was positively correlated with the molecular weight of the adsorbates and their hydrophobicity while being inversely correlated with their solubility in water. The adsorption for 2,4-D, according to the Langmuir equation, is equal to 2.078, 2.135, and 2.467 mmol/g and SBET 1600, 1720, and 1965 m2/g, respectively. The results for other herbicides showed a similar correlation. The adsorption of phenoxy herbicides was strongly pH-dependent. The ACs produced from corn biomass can be an eco-friendly choice, offering sustainable products that could be used as efficient adsorbents for removing phenoxyacetic herbicides from water.

Preparation of cellulose-based porous carbon fibers and their methylene chloride adsorption/desorption behaviors

Methylene chloride is a type of volatile organic compounds for which effective and economical treatment and recovery technologies need to be developed because it is impossible to reburn. In this study, a cellulose-based porous carbon fibers were prepared for the adsorption/desorption of methylene chloride. From the results, the specific surface area and total pore volume of cellulose-based porous carbon fibers were determined to be 1700–2220 m2/g and 0.69–1.03 cm3/g, respectively, and the micropore ratio was observed to be high. As the activation time increased, methylene chloride activity and methylene chloride retentivity increased from 51.75 % to 58.07 % and from 9.08 % to 14.92 %, respectively. Methylene chloride adsorption/desorption showed a high correlation with pore volume, Especially, methylene chloride retentivity had a linear relationship between the mesopore volume and mesopore ratio.

Mechano-chemical, high-consistency activation of kraft pulp in deep eutectic solvent of choline chloride and urea

Deep eutectic solvents (DESs) offer an appealing green medium for the activation of cellulose fibres to promote their swelling, reactivity, hydrolysis, disintegration, and solubility for further processing. Typically, DES treatments are carried out below 5 wt% consistency even though a higher solids content could enhance the fibre activation and reduce the solvent consumption. In this work, a high-consistency (HC) mechano-chemical activation of bleached softwood kraft pulp was elucidated using a simultaneous fibre treatment with DES of choline chloride-urea and a sigma-type kneader or a twin-screw extruder at a solids content of 15–35 wt% and 30 wt%, respectively. Both HC treatments efficiently triggered fibre swelling, which was indicated by an increase in the fibre width, and loosened the cell wall structure which was indicated by an increase in the mesopore volume. Mechano-chemical HC processing generated fibre fines and external fibrillation, while the molecular-level structural alteration or changes in chemical composition were minor; the intrinsic viscosity and the crystallinity of the pulp remained at their initial level and only a small amount of xylan was dissolved. Overall, HC treatment in a twin-screw extruder caused notably more severe morphological changes in the fibres than batch treatment in a sigma-type kneader. Thus, the mechano-chemical HC treatment with DES provides an industrially relevant technology for cellulose modification and opens possibilities to enhance heterogeneous cellulose modification processes in which the highly available surface area of pulp is a key parameter.

The Utilization of Rice Husk as Both the Silicon Source and Mesoporous Template for the Green Preparation of Mesoporous TiO2/SiO2 and Its Excellent Catalytic Performance in Oxidative Desulfurization.

In recent years, TiO2-based catalysts have received extensive attention from researchers for their excellent oxidative desulfurization (ODS) performances. In this paper, a series of mesoporous TiO2/SiO2 catalysts with different TiO2 loadings are prepared, using an incipient wetness impregnation method with agricultural waste rice husk as both the silicon source and mesoporous template and tetrabutyl titanate as the titanium source. The effect of different TiO2 loadings on the ODS performance of the samples is investigated, and the appropriate TiO2 loading is 2.5%. Compared with pure TiO2, the 2.5%TiO2/SiO2 sample exhibits high catalytic activity for oxidative desulfurization. This is, on the one hand, due to the high specific surface area and mesopore volume of the 2.5%TiO2/SiO2 sample. On the other hand, it is due to the uniform dispersion of TiO2 grains with an average diameter of 6.1 nm on the surface of the mesoporous SiO2 carrier, which greatly increases the active sites of the 2.5%TiO2/SiO2 sample, thus improving the catalytic activity of the sample. The recycling performances of the 2.5%TiO2/SiO2 sample are further investigated. The results show that, after fifteen cycles, the 2.5%TiO2/SiO2 sample still maintains high conversions of dibenzothiophene (99.8%) and 4,6-dimethyldibenzothiophene (99.7%) without deactivation. In addition, the 2.5%TiO2/SiO2 sample treated with TBHP aqueous solution is characterized by the technique of UV-Vis, and the Ti-peroxo (Ti-OOtBu) species, the active intermediate for the ODS of bulky organic sulfides, is successfully captured. Finally, a possible reaction mechanism for the ODS process over the 2.5%TiO2/SiO2 sample is proposed.

Optimized Electrocatalytic Adsorption Degradation of Oilfield Produced Water Using New Dimension Stable Anode

AbstractIn this study, we synthesized a novel electrode for electrocatalytic adsorption by fabricating ACF‐TiO2 via the sol‐gel method and binding it with IrO2‐TaO2. The electrode's effectiveness in treating oilfield produced water (OPW) was evaluated using batch techniques. Comprehensive characterization, including scanning electron microscopy (SEM), energy‐dispersive spectrometry (EDS), Brunauer‐Emmett‐Teller (BET) analysis, and Fourier‐transform infrared (FTIR) spectroscopy, confirmed uniform TiO2 loading onto the ACF surface, preserving structural integrity. BET analysis indicated increased mesopore volume and enhanced organic adsorption capacity without compromising microporous structure. Additionally, FTIR analysis revealed the emergence of functional groups conducive to adsorption and catalytic reactions. Freundlich isotherms and pseudo‐first‐order kinetics best fit the adsorption data. Remarkably, even after five cycles, the electrode maintained high removal efficiencies for chemical oxygen demand (COD) and oil content at 91.35 % and 91.12 %, respectively. We further investigated the complex phenomena of material adsorption, electrochemical oxidation, and desorption during electrocatalytic adsorption, highlighting the importance of solid‐phase adsorption and liquid‐phase electrocatalytic oxidative decomposition in OPW treatment. Comparison with similar electrodes and DSA electrodes demonstrated the superior performance and practicality of the IrO2‐TaO2‐ACF(TiO2) electrode. Its cost‐effectiveness and regeneration method further enhance its applicability in real‐world scenarios, emphasizing its potential in water treatment.

Effects of silico-tungstic acid on the pseudo capacitive properties of manganese oxide for electrochemical capacitors applications

In this work manganese oxide (MnO2) is modified with silico-tungstic acid (STA). Three samples are synthesized by the co-precipitation method. The powders obtained after elaboration are characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) imaging coupled to Electron Dispersive Spectroscopy (EDS) analysis and Brunauer-Emmet-Teller (BET) for their surface area determination. The effect of the modification of the manganese oxide with STA on its surface is determined. It is shown that MnO2 modified with STA exhibits better cumulative high specific surface areas and mesoporous volumes areas. For example, the sample fabricates with 10% STA (MnO2 – 10% STA) has a BET surface area of 153.6 ​m2 ​g−1 and volume area 0.92 ​cm3 ​g−1 whereas the sample without STA (MnO2 – 0% STA) has a surface area of 132.57 ​m2 ​g−1 and a mesoporous area of 0.26 ​cm3 ​g−1. The electrochemical performance analysis of the different working electrodes prepared for super-capacitors applications is carried out using cyclic voltammetry (CV)., using a solution of 0.5 M K2SO4 as an electrolyte in potential range of −0.4 and 0.9 ​V at a sweep speed of 10 ​mV/s. The CV results are correlated to those of the BET surface and mesoporous areas values Accordingly, it is shown that samples spiked with STA exhibit higher electrochemical double layer capacitance than those of none modified with STA. These measurements respectively give 38 ​F ​g−1, and 181 ​F ​g−1 for MnO2 without STA (MnO2 – 0% STA), and MnO2 modified with 10% STA (MnO2 – 5% STA).

Upcycling waste polyethylene terephthalate (PET) bottles into high-performance activated carbon for electrochemical desalination

Upcycling waste polyethylene terephthalate (PET) bottles has attracted intensive research interests. This simultaneously alleviates plastic pollution and achieves a waste-to-resource strategy. Waste PET water bottles were used to fabricate value-added activated carbon (AC) electrodes for capacitive deionization (CDI). The KOH activation temperature (greater than 700 °C) prominently affected the physi-chemical properties and desalination performance of PET-derived activated carbons (PET-AC). Profiting from a large Brunauer–Emmet–Teller specific surface area (1448 m2 g−1) with a good mesoporous structure (the ratio of the mesopore volume to the total pore volume was 41.3%), PET-AC-1000 (activated at 1000 °C) possessed a huge specific capacitance of 108 F g−1 for capacitive ion storage. Moreover, when utilized as the electrode material in single-pass CDI, PET-AC-1000 exhibited a maximum electrosorption capacity of 10.82 ± 0.11 mg g−1 and a low level of energy consumption (0.07 kWh mol−1), associated with good electrochemical charging-discharging cyclic stability. The results provide a promising facile approach to tackle the challenge of plastic pollution and promote the advancement of electrode materials for economic affordable and energy-efficient electrochemical desalination process, which meets the United Nations (UN) sustainable development goals (SDGs).

Regulating pore structure of diatomite with alkali dissolution and its influence on humidity control performance

Alkali dissolution is an effective method to regulate the pore structure of porous mineral material. The main chemical composition of diatomite is amorphous SiO2, which can be dissolved in alkali dissolution. The diatomite samples with alkali dissolution treatment were systematacially characterized by the particle size analysis, low temperature nitrogen adsorption, MIP, fractal theory, SEM, TEM, XRD, FTIR and surface hydroxyl density to analyze the pore structure and surface properties. And the humidity control performance of diatomite was tested under different temperatures and relative humidities. The relationship among pore structure, surface properties and humidity control performance were analyzed. The results show that alkali dissolution can regulate the mesoporous and macroporous of diatomite, and some new microporous can generate at high alkali dosage. The specific surface area, mesoporous pore volume, proportion of macroporous volume, surface roughness, heterogeneity of pore structure and number of hydroxyl groups on the surface of diatomite are important factors which determining the humidity control performance. The humidity control performance of diatomite is positively correlated with the specific surface area, mesoporous volume, surface roughness, heterogeneity of pore structure and number of hydroxyl groups on the surface, while is negatively correlated with the proportion of macroporous volume.

Enhanced electrocatalytic nitrate reduction via carbon material integration between Cu and Ni-foam: Mechanisms and performance analysis

This study investigates the electrocatalytic reduction of nitrates using three novel electrodes: Cu@CNFs/NF, Cu@CNTs/NF, and Cu@CB/NF, synthesized via an impregnation-calcination-electrodeposition technique. The emphasis is on the role of different carbon materials, which serve as the base or matrix for Cu, and their influence on nitrate reduction and nitrogen selectivity. Experimental results indicated that all three-electrode variants outperformed the conventional Cu/NF electrode in nitrate reduction and nitrogen selectivity. Among these, the Cu@CNFs/NF electrode emerged as the standout performer, achieving an impressive nitrate reduction rate of up to 98 % and a nitrogen selectivity of 51 % under the optimized experimental conditions (pH 7, nitrate concentration of 100 mg∙L-1 as NO3–-N, a current density of 8 mA cm−2, a sodium sulfate concentration of 0.5 g∙L-1, 120 min, anode: Ti/RuO2-IrO2). Stability tests confirmed that the Cu@CNFs/NF electrode maintained over 97 % nitrate removal efficiency across ten cycles, highlighting its robustness and potential for practical water treatment applications. A significant enhancement in nitrogen selectivity of Cu@CNFs/NF to 96 % was observed when using 0.75 g∙L-1 NaCl as the electrolyte during an extended electrolysis period of 180 min, underscoring its potential to optimize catalytic efficiency. Characterization data from SEM, XRD, and other analyses substantiate that the incorporation of carbon materials augments the active sites of copper; Nitrogen adsorption–desorption experiments further illustrate that the integration of carbon materials leads to an increase in mesoporous volume. This increase promotes adsorptive interactions, enhances the conversion of intermediates, and contributes to the improvement of nitrate reduction and nitrogen selectivity. These results highlight the potential of tailored carbon material integration for enhancing the electrocatalytic performance of electrodes in practical water treatment applications.

Fe3C@C composite fiber mats prepared by electrospinning with heat treatment and their application to Li-S batteries

The main challenges facing Li-S batteries stem from the low conductivity of sulfur and the dissolution of lithium polysulfides. This study addresses these issues by synthesizing Fe3C@C nanofibers through electrospinning followed by heat treatments, which are then applied as an interlayer in Li-S cells. The pre-oxidation temperature is adjusted to achieve the desired material properties, in which Fe3C nanoparticles are embedded in graphitic carbon nanofibers, resulting in a high specific surface area and mesopore volume. This configuration provides excellent polysulfide adsorption and catalytic properties for their further conversion. Consequently, when used as an interlayer, the electrochemical performance of the cell, including discharge capacity (first: 1174 vs. 850 mAh g−1 at 0.1 C), stability (852 vs. 400 mAh g−1 after 100 cycles), and rate-capability (620 vs. 100 mAh g−1 at 2 C), is significantly enhanced compared to cells without interlayer.

Evaporation-induced self-assembly of hierarchical zinc silicate hybrid scaffolds for bone tissue engineering: Meso and macro scale porosity design

In this study, zinc silicate hybrid scaffolds with hierarchical meso/macroporous structures were synthesized using evaporation-induced self-assembly and sacrificial foamy templates. F127 triblock copolymer and polyurethane (PU) foam served as templates for mesoporosity and macroporosity, respectively. The scaffolds were calcined at 550, 650, and 750 °C for 2 h to remove the templates and form the crystalline phase. Analytical techniques, including BET, XRD, SEM, FTIR, and STA, were used to study the impact of calcination temperature on the scaffolds' meso-texture and crystalline phase. Results showed that increasing the calcination temperature to 750 °C significantly enhanced the overall crystallinity. The crystallized ZnO content increased from 10.3 wt% to 32 wt%, and the willemite (Zn2SiO4) crystalline phase formed. Willemite content was approximately 3 wt% at 650 °C and 67 wt% at 750 °C, as determined by quantitative XRD analyses via Rietveld refinement. The emergence of the willemite phase adversely impacted the specific surface area, leading to a reduction from 123.18 m2/g to 2.18 m2/g, and compromised meso-texture-related characteristics, indicating a substantial disruption in mesoporosity. The pure willemite sample was also obtained by increasing the calcination temperature up to 1000 °C. Although the sample contained no secondary phase, the specific surface area and total mesopore volume were drastically reduced, indicating the negative effect of high calcination temperature on mesoporosity. In contrast to the mesostructure, the macrostructure of the scaffolds exhibited negligible sensitivity to calcination temperature, maintaining a mean macropore diameter of around 200 μm. Furthermore, the in vitro performance of the scaffolds was evaluated by assessing apatite formation ability, degradability, and cytocompatibility. It was demonstrated that the scaffolds calcined at 750 °C exhibited superior performance in terms of apatite formation and cytocompatibility when cultivated with MG-63 human osteosarcoma cells.

Effect of Tectonic Deformation on the Pore System and Methane Adsorption of Anthracite Coal.

Tectonic deformation significantly alters the physical structure of coals, holding great importance to the coal mining industry and coalbed methane. In this study, eight anthracite coal samples with varying degrees of deformation were collected to investigate the effects of tectonic deformation on the pore system and CH4 adsorption of anthracite coals. In addition, low-temperature gas adsorption (N2 and CO2), Raman spectroscopy, and CH4 isothermal experiments were performed. The results revealed that coal samples with higher degrees of deformation exhibited larger ratios of D-band intensity to G-band intensity (I D/I G), indicating increased molecular defects induced by tectonic deformation. As the deformation degree of the coal samples increased, the mesopore volume increased from 0.00044 cm3/g (primary coal) to 0.0019 cm3/g (scaly coal). Conversely, the micropore volume tended to decrease with the increasing deformation degree of the coal samples. Moreover, the impact of deformation degree on the CH4 adsorption capacity of anthracite coals was complex. With the deformation degree increasing, the Langmuir volume initially decreased from 32.0 to 24.55 cm3/g and then rose to 30.14 cm3/g. This complexity arose from the differential effects of tectonic deformation on various pore types, where micropores and mesopores collectively determined the CH4 adsorption capacity of anthracite coals. This study analyzed the influence of tectonic deformation on the pore structure and CH4 adsorption capacity at the molecular level, providing valuable insights for evaluating the in situ CH4 content in anthracite coal seams.

Organosilane-assisted synthesis of EU-1 nanozeolite aggregates with improved activity in catalytic cracking of n-hexane

One-dimensional microporous zeolite, EU-1, exhibits more favorable selectivity of propylene in cracking of petroleum components. However, it faced the problem of low catalytic activity for the poor utilization of active sites. In this work, dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (TPOAC) was used to functionalize protozeolitic units and inhibit the excessive growth of crystals by the long hydrophobic alkyl chain. The introduction of TPOAC decreased the crystal sizes into nanoscale, enhanced the mesoporous volume of EU-1 zeolite, and exposed more external acid sites. Moreover, TPOAC could interact with Al species, and in this case, fewer Al atoms were incorporated into the zeolite framework, reducing the acid strength and amount. Intelligent gravitation analyzer test indicated that the zeolite prepared with the presence of 0.30 g TPOAC exhibited the largest accessible volumes in n-hexane adsorption, and the highest accessibility of acid sites, which synergistically promoted cracking of n-hexane for the production of light olefins.

Multi-fractal characteristics of pore system in deep organic-rich shales of the Wufeng-Longmaxi formation in the Sichuan Basin and their geological significance

The heterogeneity of pore system of deep shale reservoir determines the occurrence, enrichment and migration behavior of shale gas within shales. In this study, multi-fractal analysis was applied to analyze CO2 and N2 adsorption data for obtaining multi-fractal parameters including Hurst index and multi-fractal spectrum (D5--D5+) of the deep Wufeng-Longmaxi shales collected from the Sichuan Basin, China, in order to study the connectivity and heterogeneity of micropore pores and meso-macropores as well as their influencing factors. The results showed that pore system of the Wufeng-Longmaxi deep shale exhibits distinct multifractal nature. There exists significant differences in the pore volume (PV) of micropores (<2 nm), mesopore (2–50 nm), and macropore (>50 nm) across different shale lithofacies due to their differences in TOC content and mineral composition. The heterogeneity and connectivity of micropores and meso-macropores within deep shales in the Sichuan Basin are controlled by multiple factors including shale lithofacies, burial depth, and pressure coefficients. Notably, siliceous shale (SL) and calcareous/argillaecous siliceous shale (C/ASL), known as sweet spot for current shale gas exploitation, exhibits characteristics such as relative low micropore connectivity, high micropore heterogeneity, high micropore PV and low meso-macropore connectivity. These suggest that isolated pressure-sealing compartment is easier formed within the overpressured SL and C/ASL. Thus, pressure in these shales is less likely to release during the Yanshanian-Xishanian tectonic uplift process, favoring the preservation of organic matter (OM) pores and residual interparticle pores, which is conducive to the accumulation of deep shale gas dominated by free gas.

The quantitative study of residual acid damage of low permeability carbonate rock based on NMR test

The Leikoupo carbonate reservoirs in the West Sichuan gas field generally exhibit low porosity and permeability characteristics. After acidizing, the fluid flowback rate is only 46%, and a large amount of residual acid remains in the reservoir, causing damage to the pores. In this study, the rheological tests were first carried out to reveal the rheological characteristics of fresh and residual acid with different thickener contents. Then, the change in core permeability before and after acid flooding was tested by core-flood tests, and the effects of acid on pore structure in various scales were analyzed in nuclear magnetic resonance (NMR) tests. The research results show that the average viscosity of residual acid increased to about 157.14% of the fresh acid and exhibited large viscosity fluctuations, which may be caused by the formation of aggregates combined with thickener and insoluble. The change rate of core permeability (both improvement and damage) decreased with the increase in thickener content, and the effect was more significant when the thickener content changed from 0.6% to 0.8%. Under different thickener addition amounts, fresh acid mainly improved the core permeability. After core-flooding, micropores and mesopores (51.26–632.15 μm) were dissolved and enlarged, forming mesopores and macropores (632.15–3597.73 μm); when the thickener content increased to 0.8%, the solubility of acid decreased, and the pore volume increment and maximum pore size both decreased. On the other hand, residual acid mainly damages the core, thickener molecules in the acid occupying mesopore, leading to an overall shift in pore distribution from mesopores (145.24–335.53 μm) to micropores (20.59–126.32 μm), with the thickener content increased to 0.8%, the damage volume of mesopore increased by 723.90%. Based on the research results, the reduced thickener content was initially applied to the West Sichuan gas field, achieving a better acidizing effect.

Enhancement of engineering properties of cement mortars with masonry construction and demolition fines via carbon dioxide utilization, storage and chemical treatment

Shortage of natural sand is severely affecting the global construction industry. The construction sector also generates a substantial amount of construction and demolition (C&D) waste of which masonry wastes constitute a major fraction. Using a circular economy approach, this article explores the feasibility of using treated masonry waste fines (MWF) to replace 75 % of natural sand in Portland cement-based mortars. The treatment consists of a combination of acid washing and CO2 curing to improve the engineering properties of MWF-cement mortars. 0.1 mol/L and 0.5 mol/L (M) H2SO4 were used for chemical treatment of the MWF followed by CO2 curing at 50,000 ppm for 4 hours. Mortars containing treated MWF (MWF-0.1 M-C and MWF-0.5 M-C) were subject to conventional curing (moist curing followed by dry curing at 30 ◦C and 65 % RH) and carbon sequestration via accelerated carbonation curing. Experimental findings suggest that combined treatment with acid and CO2 reduces the pore volume by 13 – 27 % in the pore size range of 10 – 100 nm in MWF. Consequently, mortars with MWF-0.1 M-C and MWF-0.5 M-C show 29 – 30.50 % higher compressive strength at 28-d age and a 29 – 36 % reduction in total shrinkage compared to mortars with similar dosages of as-received MWF. This ensures statistically similar strength and shrinkage as that of the plain mortar (with 100 % natural sand), demonstrating the potential for 75 % sand replacement using treated MWF. Furthermore, carbon sequestration of 16.40 – 19 % by mass of Portland cement is achieved, which contributes to a 15 % enhancement in early strength and reduces the mesoporous volume and shrinkage by up to 43 % and 15–19 % respectively. In summary, the research offers a pathway to recover a “new sand” from C&D wastes , which could be used to manufacture masonry construction products with reduced demand for natural sand.

Disproportionation and Transalkylation of Phenol and Dimethylphenol on Zeolite Catalysts

AbstractSubstantial amounts of phenolic compounds are present in medium‐low temperature coal tar (MLCT), of which dimethylphenol (DMP) is not as valuable to be utilized as the more abundant cresol due to its complex composition and difficulty in isolation. In this study, the disproportionation and transalkylation reactions of MLCT‐related model compound, i.e., 2,6‐DMP, in phenol over zeolite catalysts are investigated using a fixed‐bed reactor for sustainable new option to utilize MLCT‐derived phenolic mixtures. Reactivity is promoted at high temperatures and associated with zeolite acidity and pore structure. Since disproportionation and transalkylation reactions have certain spatial requirements, the micropores of MFI‐type zeolite may cause spatial barriers that make it difficult to carry out the reactions. MCM‐22, characterized by MWW‐type zeolite, maximized the conversion of 2,6‐DMP due to its strong Bronsted acidity and large mesopore volume. FAU‐type zeolite HY with a 3D large 12‐ring through‐channel shows relatively small spatial confinement and certain molecular sieving ability, which enables bimolecular reactions while allowing cresols to flow out of the pores efficiently to obtain the highest cresol selectivity. The addition of phenol significantly inhibits the spontaneous disproportionation of 2,6‐DMP to tricresol. Besides, o‐cresol dominate the cresol products, suggesting that the selectivity of o‐cresol is kinetically controlled.

Optimization of hydrothermal autoclaving parameters for the synthesis of porous ceramics from porcelain tile polishing residue

Porous ceramics were synthesized using porcelain tile polishing residue (PTPR) and slaked lime (Ca(OH)2) as a reinforcing agent through a hydrothermal autoclaving method. The process parameters, including the quantity of slaked lime added, the hydrothermal autoclaving temperature, and the reaction duration, were optimized meticulously. The composition, structure, thermal and physical properties of the samples were thoroughly analyzed via Brunauer–Emmett–Teller (BET) measurements, powder X-ray diffraction (PXRD), and scanning electron microscopy (SEM). The results indicated that the incorporation of slaked lime and hydrothermal autoclaving led to the formation of calcium silicate hydrate, which corresponded with an enhancement in the strength of the sample. Notably, when the quantity of slaked lime added was optimized at 30 wt%, the formation of tobermorite (5CaO·6SiO2·5H2O) was detected. At a hydrothermal autoclaving temperature of 150 °C, the formation of only sheet-like calcium silicate hydrate was observed. In contrast, at an elevated temperature of 180 °C and 210 °C, needle-like tobermorite was successfully synthesized. The porous ceramic with the most favorable structure was obtained through autoclaving at 180 °C for 10 h with 30 wt% slaked lime, exhibiting a total pore volume of 0.11 mL/g, a specific surface area of 26.35 m2/g, and a mesoporous volume fraction of 90.40%.

Synthesis of natural heteroatom co-doped porous carbon by co-pyrolysis of kapok tree and peanut bran coupled with microwave activation

The application of biomass-derived porous carbon in supercapacitors should focus on heteroatom doping and modulation of pore structure. This work presented a technique for synthesizing natural heteroatom co-doped porous carbon by co-pyrolysis coupled with microwave activation of the kapok tree (KT) and peanut bran (PB). PB is a natural heteroatom donor and a precursor of porous carbon. Some S-containing radicals and N-containing functional groups in PB are successfully retained in the biochar, facilitating heteroatom doping in NHDPC. When the mixing ratio of KT and PB is 1:1, the mesoporous volume of NHDPC-5PB can reach 1.81 cm3/g. Relative to the porous carbon NHDPC-0PB synthesized solely through KT pyrolysis, the mesoporous volume of NHDPC-5PB increases by 74.04 %. Moreover, the specific capacitance of NHDPC-5PB at 0.2 A/g attains 346.8 F/g, which is a 36.6 % increase compared to NHDPC-0PB. This study presents a new strategy to prepare natural heteroatom co-doped porous carbon by co-pyrolysis of heteroatom-rich biomass as a heteroatom donor with lignocellulosic biomass.