Microporous Structure Research Articles

Integrating Cu+/Cu0 sites on porous nitrogen-doped carbon nanofibers for stable and efficient CO2 electroreduction to multicarbon products

The Cu+/Cu0 sites of copper-based catalysts are crucial for enhancing the production of multicarbon (C2+) products from electrochemical CO2 reduction reaction (eCO2RR). However, the unstable Cu+ and insufficient Cu+/Cu0 active sites lead to their limited selectivity and stability for C2+ production. Herein, we embedded copper oxide (CuOx) particles into porous nitrogen-doped carbon nanofibers (CuOx@PCNF) by pyrolysis of the electrospun fiber film containing ZIF-8 and Cu2O particles. The porous nitrogen-doped carbon nanofibers protected and dispersed Cu+ species, and its microporous structure enhanced the interaction between CuOx and reactants during eCO2RR. The obtained CuOx@PCNF created more effective and stable Cu+/Cu0 active sites. It showed a high Faradaic efficiency of 62.5% for C2+ products in H-cell, which was 2 times higher than that of bare CuOx (∼31.1%). Furthermore, it achieved a maximum Faradaic efficiency of 80.7% for C2+ products in flow cell. In situ characterization and density functional theory (DFT) calculation confirmed that the N-doped carbon layer protected Cu+ from electrochemical reduction and lowered the energy barrier for the dimerization of *CO. Stable and exposed Cu+/Cu0 active sites enhanced the enrichment of *CO and promoted the C–C coupling reaction on the catalyst surface, which facilitated the formation of C2+ products.

Layout optimization of pore microstructure in fluid-saturated porous media using Galerkin decoupling technology and independent continuous mapping method (GDT-ICM)

A layout optimal design method combining Galerkin decoupling technology and an independent continuous mapping method (GDT-ICM) is proposed to rearrange the layout of pore microstructure. Firstly, the Galerkin decoupling technology (GDT) is employed to solve the Brinkman equation for fluid flow in fluid-saturated porous media, which integrates the Stokes equation and Darcy's law. Within this framework a self-programmable element balance equation is developed. Secondly, a permeability interpolation function is defined for each element, incorporating the permeability of the fluid and pore microstructure. This function distinguishes strictly between the fluid domain and the pore domain. Pore microstructures with arbitrary shape including permeability information are established in an Euler mesh by introducing the Carman-Kozeny equation, shape functions, the Joukowski mapping and filter functions (a modified arctan mapping function and the MATLAB inpolygon function) based on the ICM method. Thirdly, a layout optimization model aiming at minimizing energy dissipation is established to accomplish the optimal distribution of pore microstructures. A sensitivity analysis is performed with respect to design variables and the optimal model is solved by a genetic algorithm. Numerical results demonstrate that the proposed method is effective and feasible in 2D-space. The maximum velocity within the fluid field is reduced by 45 %, and the issue of localized high pressure occurring around the pore is resolved. This paper provides guidance for solving the Brinkman coupled equation and the layout optimization of the microstructure in porous media.

Porous and Conductive Fiber Woven Textile for Multi‐Functional Protection, Personal Warmth, and Intelligent Motion/Temperature Perception

AbstractIndustrialization and human activities have introduced numerous hazards, including exposure to harsh chemicals, radiation, static electricity, and fire risks, particularly in high‐risk sectors such as engineering, rescue operations, military, and aerospace. This study presents a multi‐functional protective textile developed from a conductive fiber composed of polytetrafluoroethylene (PTFE) and carbon nanotubes (CNT), crucial for ensuring personal safety. The conductive fiber demonstrates remarkable strength (17.3 MPa), high porosity (76%), and significant electrical conductivity (185 S m−1), coupled with excellent fineness and flexibility due to its dual‐nanofibrous structure. The resulting textile exhibits exceptional hydrophobicity, chemical resistance, and high electromagnetic interference shielding effectiveness (29 dB in the X‐band), alongside a superior UV protective factor (>3000) and anti‐static properties. Notably, it possesses outstanding electro/photo thermal conversion capabilities, enabling consistent heat generation for personal warmth. Additionally, the textile responds electrically to deformation and temperature changes, facilitating intelligent applications such as motion and temperature monitoring and fire alerts. This work offers a novel strategy for fabricating PTFE‐based composite fibers with porous microstructures and high electrical conductivity, setting a new standard for next‐generation protective clothing with advanced functionalities.

Catalytic and Electrochemical Study of Cu-ZSM-5/MCM-41.

Hierarchically structured micro-mesoporous ZSM-5/MCM-41 composite materials incorporating copper ions were synthesized using pre-synthesized ZSM-5 and cetyltrimethylammonium bromide (CTAB) as a template for forming the MCM-41 structure. The composites were characterized through powder X-ray diffraction, N2 adsorption-desorption, diffuse reflectance spectroscopy (UV-vis DRS), Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and energy dispersive X-ray spectroscopy. X-ray diffraction confirmed well-ordered ZSM-5 and MCM-41 structures, and UV-vis DRS showed successful copper ion incorporation. N2 adsorption-desorption revealed the presence of both microporous and mesoporous structures. To evaluate their catalytic performance, Cu-incorporated ZSM-5/MCM-41 composite catalysts were assessed through the oxidation reaction of ethylbenzene using tert-butyl hydroperoxide (TBHP) as the oxidizing agent. With a 9% (w/w) Cu-ZM-5 (5 wt % copper-incorporated ZSM-5/MCM-41) catalyst and an oxidant to ethylbenzene molar ratio of 2:1 at 40 °C in the absence of a solvent for 4 h, the process yielded acetophenone (93.2%) as the major product. Additionally, these Cu-incorporated composites were examined as electrode materials for electrochemical storage. Cyclic voltammetry and galvanostatic charge-discharge studies showed that Cu-ZM-5 exhibited pseudocapacitive behavior, with a capacitance of up to 366 F g-1 at a current density of 1 A g-1, surpassing ZSM-5 and ZSM-5/MCM-41. These results highlight Cu-ZM-5's potential as an effective electrode material for electrochemical storage applications like supercapacitors.

Bioinspired Glycopeptide Hydrogel Reestablishing Bone Homeostasis through Mediating Osteoclasts and Osteogenesis in Periodontitis Treatment.

Irreversible alveolar bone resorption is one of the important clinical manifestations of periodontitis, which is initiated by a plaque biofilm and exacerbated by the imbalance of osteoclast activity and osteogenesis, affecting a patient's masticatory function and resulting in a high recurrence rate of periodontitis. Herein, to reestablish bone homeostasis in periodontitis, a minocycline hydrochloride (MH)-loaded glycopeptide hydrogel (MH/GRWgel) is fabricated to mediate alveolar bone absorption through sequential antibacterial and RANKL-blocking activities. GRWgel shows an ECM-like fibrous and porous microstructure serving as a scaffold for cell proliferation and differentiation and holds the merits including injectability, self-healing properties, and good biocompatibility. After injection in situ, MH is released rapidly from the hydrogel in the early stage, demonstrating a potent antimicrobial effect to combat the biofilm in the deep periodontal pocket. Moreover, MH/GRWgel exhibits a high specific binding efficiency with RANKL to suppress osteoclast maturation by shielding the RANKL/RANK interaction and enhancing osteogenic differentiation, thereby synergistically regulating bone homeostasis. In the rat periodontitis model, MH/GRWgel significantly curtails periodontitis progression through antimicrobial activity, inhibition of alveolar bone resorption, and promotion of bone regeneration, which is superior to the treatment of a commercial gel. These findings suggest that MH/GRWgel with superiority in regulating bone homeostasis provides a promising therapeutic strategy for periodontitis.

A flexible capacitive proximity-tactile dual-mode sensor based on the biomimetic petal-like electrode

Flexible capacitive proximity-tactile dual-mode sensors not only have good stability, non-contact detection distance and sensitivity, but also can get rid of the limitation of single contact sensing performance. It integrates other functions such as extensibility, tactile perception, etc., forming dual-mode flexible wearable electronic skins with strong adaptability to application scenarios. However, under the premise of fully balancing the manufacturing process and cost, how to effectively and significantly improve the non-contact and contact performance of capacitive flexible proximity sensors remains an important issue. By utilizing the edge effect and biomimetic concept, we propose a flexible capacitive dual-mode sensor based on petal-like electrode, which has a relative variation of capacitance to −32.4 % and can detect objects within 5 cm. With the further assistance of the porous microstructure dielectric layer, the tactile performance of the sensor exhibits high sensitivity of 0.132 kPa−1, low pressure resolution of 6.9 Pa, and good stability after thousands of pressure test cycles. In addition, an object detection system based on a flexible capacitive dual-mode sensor array has been developed. The experimental results show that the shape and position of the approaching object are detected in proximity mode, and the size and position distribution of pressure are detected in tactile mode. The ideal performance of sensor has broad application prospects in fields such as spatial recognition, human-computer interaction, and intelligent electronic skin.

Advancing self‐lubricating technology: Selective laser sintering molding assisted development of copper‐based polytetrafluoroethylene /graphite composites

AbstractThis study introduces an innovative technique for the fabrication of copper‐based polytetrafluoroethylene (PTFE)/graphite self‐lubricating composites. By harnessing the exceptional capabilities of selective laser sintering (SLS), we efficiently create three‐dimensional, continuous, and porous graphite preforms. Following this, the composite is formed through a combination of electroplating and vacuum extrusion methods. Subsequently, PTFE was vacuum impregnated into the microporous structure of the graphite preforms, and the composites were obtained through freeze‐drying, plasticizing, and machining processes. The resulting copper‐based PTFE/graphite self‐lubricating composites exhibit an exceptional blend of properties. Notably, there is a significant reduction in the average coefficient of friction, dropping from 0.14 to 0.02, and a marked decrease in the wear rate, from 1.358 × 10−5 to 1.109 × 10−5 mm3/N·m, as compared to graphite as a standalone lubricant. This represents a substantial improvement in performance, underscoring the effectiveness of the proposed fabrication method.Highlights The porous graphite with controllable shape distribution was prepared. Surface copper plating improves surface bonding. Controllable copper matrix composites with double lubricant were prepared. The average friction coefficient is as low as 0.02.

Single-Crystalline 3D Covalent Organic Frameworks with Exceptionally High Specific Surface Areas and Gas Storage Capacities.

Single-crystalline covalent organic frameworks (COFs) are highly desirable toward understanding their pore chemistry and functions. Herein, two 50-100 μm single-crystalline three-dimensional (3D) COFs, TAM-TFPB-COF and TAPB-TFS-COF, were prepared from the condensation of 4,4',4″,4‴-methanetetrayltetraaniline (TAM) with 3,3',5,5'-tetrakis(4-formylphenyl)bimesityl (TFPB) and 3,3',5,5'-tetrakis(4-aminophenyl)bimesityl (TAPB) with 4,4',4″,4‴-silanetetrayltetrabenzaldehyde (TFS), respectively, in 1,4-dioxane under the catalysis of acetic acid. Single-crystal 3D electron diffraction reveals the triply interpenetrated dia-b networks of TAM-TFPB-COF with atom resolution, while the isostructure of TAPB-TFS-COF was disclosed by synchrotron single-crystal X-ray diffraction and synchrotron powder X-ray diffraction with Le Bail refinements. The nitrogen sorption measurements at 77 K disclose the microporosity nature of both activated COFs with their exceptionally high Brunauer-Emmett-Teller surface areas of 3533 and 4107 m2 g-1, representing the thus far record high specific surface area among imine-bonded COFs. This enables the activated COFs to exhibit also the record high methane uptake capacities up to 28.9 wt % (570 cm3 g-1) at 25 °C and 200 bar among all COFs reported thus far. This work not only presents the structures of two single-crystalline COFs with exceptional microporosity but also provides an example of atom engineering to adjust permanent microporous structures for methane storage.

The influence of pore throat heterogeneity and fractal characteristics on reservoir quality: A case study of chang 8 member tight sandstones, Ordos Basin

The Chang 8 member of the Yanchang Formation in the Ordos Basin exhibits extensive development of tight sandstone reservoirs. In comparison to conventional reservoirs, these tight sandstone reservoirs demonstrate smaller pore-throat systems and stronger heterogeneity due to interactions between inherent sedimentary components and various diagenetic processes. To further investigate the influence of microscopic pore throat structure on macroscopic physical properties and oil content within the reservoir, a comprehensive study was conducted utilizing high pressure mercury injection, nuclear magnetic resonance, X-CT scanning, and other pore throat testing methods. This study was complemented by observation techniques such as polarizing microscope, scanning electron microscopy, and laser confocal imaging, to study the pore throat system of reservoirs under the influence of different sedimentary components and diagenesis. By comparison, it is observed that the radius of the primary pore throat system in the tight sandstone reservoir ranges from 0.01 to 1 μm. The structural characteristics of the pore throat system significantly impact the macroscopic physical properties of the reservoir. Due to variations in testing methods, high pressure mercury injection, nuclear magnetic resonance (NMR), and X-ray computed tomography (X-CT) reveal different fractal dimensions of the reservoir's pore throat system. Therefore, it is better to respectively utilize fractal dimension Df2, Df2-NMR, Df2-CT, and pore throat parameters to characterize the microscopic pore throat system with a radius ranging from 0.01 to 1 μm. The decrease in the average pore throat radius and the increased irregularity of pore shape contribute to heightened heterogeneity in the micro-pore throat structure within the reservoir. This negatively impacts its physical properties and oil content. Furthermore, it is important to note that the minimum threshold of pore throat radius plays a crucial role as a primary factor determining the fluid seepage capacity within this reservoir. Moreover, when isolated pores exist, reduced fluid mobility ensues, which further worsens the seepage conditions of the reservoir. The chlorite rims development reservoir shows a low fractal dimension in its micro-pore throats, contributing to superior macroscopic petrophysical properties and oil content. However, compression, siliceous cementation, and calcite cementation negatively impact the average pore throat radius by increasing micropores, inaccessible pores, and narrow throat content. This results in a stronger heterogeneity of the pore throat structure, leading to poor seepage conditions and lower oil content.

Unravelling the effects of drying techniques on Porphyra yezoensis: Morphology, rehydration properties, metabolomic profile, and taste formation

This study explored the impact of sun drying (SD), freeze drying (FD), oven drying (OD), and microwave drying (MD) on the morphology, rehydration properties, metabolomic profile, and taste formation of Porphyra yezoensis. FD elicited a brighter colour, smooth surface, porous microstructure, and strong rehydration properties in P. yezoensis, while dramatically maintaining the umami, sweetness, and saltiness. OD and MD decreased structural openness owing to tissue collapse and affected water absorption. Metabolomic analysis revealed 1030 metabolites, among which taste-related compounds, especially free amino acids, nucleotides, organic acids, and their derivatives, were the main biomarkers for distinguishing the different drying methods. Their related metabolic pathways, such as taurine and hypotaurine metabolism; purine metabolism; glyoxylate and dicarboxylate metabolism; and citrate cycle, were the most active. A metabolic pathway network of the main taste compounds was built to provide novel insights into the mechanisms underlying the taste profile changes associated with different drying methods.

Enhanced hydrogen storage via microporous defects and Cu(I) sites in HKUST-1

A series of microporous defective HKUST-1 materials (DMT-HK-nF) are synthesized employing varying amounts (n = 10, 30, and 50 wt%) of 3,5-dinitrobenzoic acid (DNBA) and 1,3,5-benzene tricarboxylic acid as linkers. Subsequently, stepwise washing and solvent exchanges are conducted to enhance the density of Cu(I) sites and increases the surface area. DMT-HK-30F exhibits superior H2 storage capacity (2.55 wt% at 77 K, 100 kPa and 0.93 wt% at 298 K, 7 MPa), approximately 41% and 48% higher compared to pristine HKUST-1 (1.82 wt% at 77 K, 100 kPa, and 0.63 wt% at 298 K, 7 MPa), respectively. This improvement is attributed to an increase in Cu(I) sites and the introduction of linker defects. However, further addition of DNBA decreases the H2 storage capacity due to a reduction in Cu(I) sites and surface area caused by the formation of “missing metal cluster” defects. This study demonstrates that the simultaneous introduction of appropriate defects and high-density Cu(I) sites into the microporous structure is an effective strategy for enhancing the hydrogen storage performance of metal-organic frameworks.

New insights into the effects of silicate modulus, alkali content and modification on multi-properties of recycled brick powder-based geopolymer

Utilizing recycled brick powder (RBP) as a green precursor to prepare alkali-activated RBP-based geopolymer (AABG) not only broadens the existing system of alkali-activated materials but also achieves the high-value and low-carbon utilization of clay brick waste. This paper aims to systematically investigate the influence of silicate modulus and alkali content of the alkali-activator on the multi-properties of AABG, while proposing multi-path modification methods to optimize AABG performance. Substituting an appropriate amount of metakaolin with RBP contributes to optimizing the performance of metakaolin-based geopolymers. However, the micro-macro properties of AABG are significantly inferior to those of metakaolin-based geopolymer. Under the same silicate modulus, the micro-macro properties of AABG first improve and then deteriorate with the increase in alkali content. With the alkali content of 8 %, the AABG owns the best microstructure and macro properties. When the alkali content remains constant, an appropriate increase in the silicate modulus of alkali-activator contributes to the performance enhancement of AABG mortar. The average pore diameter of AABG-1.2M-8%, AABG-1.4M-8%, and AABG-1.4M-4% paste is 69.4 nm, 61.8 nm and 111.9 nm. Overall, the AABG with 1.6M silicate modulus and 8 % alkali content shows good performance. For the multi-path modification methods of AABG, decreasing the w/b ratio of AABG can enhance its compressive strength and permeability resistance. Besides, increasing the curing temperature of AABG can optimize its micro-pore structure and macro-properties, achieving optimal performance at a curing temperature of 80 °C. Finally, mixing Ca(OH)2 into AABG promotes the formation of more C-A-S-H, thereby further enhancing the AABG performance. Optimizing the silicate modulus, alkaline content and modification methods, it is feasible to produce AABG with superior micro-macro properties.

Defect-Engineered MOF-801/Sodium Alginate Aerogel Beads for Boosting Adsorption of Pb(II).

Metal-organic frameworks (MOFs) are attractive adsorbents for heavy metal capture due to their superior stability, easy modification, and adjustable pore size. However, their inherent microporous structure poses challenges in achieving a higher adsorption capacity. Defect engineering is considered a simple method to create hierarchical MOFs with larger pores. Here, we employed l-aspartic acid as a mixed linker to bind Zr4+ clusters in competition with fumaric acid of MOF-801 to create defects, and the pore size was increased from 4.66 to 15.65 nm. Mercaptosuccinic acid was subsequently used as a postexchange ligand to graft the resultant MOF-801 by acid-ammonia condensation to further expand the pore size to 22.73 nm. Notably, the -NH2, -COOH, and -SH groups contributed by these two ligands increased the adsorption sites for Pb(II). The obtained defective MOF-801 with larger pores was thereafter loaded onto sodium alginate to form aerogel beads as adsorbents, and an adsorption capacity of 375.48 mg/g for Pb(II) was achieved, which is ∼51 times that of pristine MOF-801. The aerogel beads also exhibited outstanding reusability with a removal efficiency of ∼90.23% after 5 cycles of use. The adsorption mechanism of Pb(II) included ion-exchange interaction, as well as chelation interactions of Pb-O, Pb-NH2, and Pb-S. The versatile combination of defect engineering and composite beads provides novel inspirations for MOF modification for boosting heavy metal adsorption.

MoO3 and AlF3 effect on the properties of porous mullite ceramics with needle‐like microstructure

AbstractPorous mullite ceramics were synthesized via ceramic processing using a local industrial kaolin, alumina, and with AlF3 and MoO3 precursor additives to catalyze the formation of pores and acicular mullite grains. The textural properties, crystalline phases, microstructures, and mechanical properties of the obtained samples were comprehensively analyzed and compared with a reference mullite formulated without additives. The obtained ceramics have a well‐defined porous microstructure, with a porosity of about 50%, and a pore size distribution in the 0.1–2 µm range. Ceramics that involve the addition of MoO3 present well‐defined acicular mullite grains, with slightly higher porosity, larger pores, and better mechanical resistance compared to those processed using AlF3.To correlate the ceramic porosity with its mechanical properties, a simple model of spherical pores was proposed to assess the flexural strength of the dense ceramic. It was found that the inclusion of additives promoting needle‐like microstructures increases the mechanical resistance up to four times the value determined for the ceramic without additives (flexural strength up to 390 MPa for zero‐porosity extrapolation). These results, together with the refractoriness of mullite, allow inferring the potential applications of the developed materials as structural ceramics with relatively low density and for filtering applications.

Dendrite‐Free Zn Anode Modified with Prussian Blue Analog for Ultra Long‐Life Zn‐Ion Capacitors

AbstractThe main challenge for aqueous zinc‐ion capacitors is the low stability of zinc anode. In this study, a Prussian blue analog (PBA) has been coated on the surface of zinc foil to create an inorganic protective layer. This layer features a three‐dimensional open microporous structure, which not only endows it with excellent pseudocapacitive properties but also serves as an effective barrier against dendrite growth. The presence of PBA coating can increase the nucleation point of zinc ions and provide a low‐energy barrier for the rapid migration of zinc ions. Hence, the PBA@Zn ||PBA@Zn symmetric cell exhibits exceptional cycling stability, enduring over 1400 h of operation at a current density of 1 mA cm−2 and a capacity of 1 mAh cm−2. The PBA@Zn||AC capacitor demonstrated a discharge capacity of 46.23 mAh g−1 after 10 000 cycles at a current density of 1 A g−1, with a capacity retention of 92.41%, whereas the discharge capacity of Zn||AC capacitor is only 16.02 mAh g−1, with a capacity retention of 23.13%. The PBA@Zn||AC capacitor exhibited remarkable endurance and stability, retaining a substantial discharge capacity of 32.7 mAh g−1 after 10 000 cycles at 10 A g−1. Density Functional Theory (DFT) calculations also show that PBA has a strong interaction with Zn and exhibits superior zincophilic ability. This study reports industrially applicable low‐cost Prussian blue analogs as artificial interfacial protective layers for improving the cycling stability of zinc anode with a low‐energy barrier for rapid migration of zinc ions especially at high current density.

Molecular Dynamics Simulations of Lubricant Supply in Porous Polyimide Bearing Retainers

Space bearing retainers are widely made of a porous, oil-impregnated material due to the unmaintainability of spacecraft. Porous polyimide (PI) material with a certain micropore structure can be used as a lubricant storage and migration channel to realize the lubricant circulation supply in the bearing system. In this work, molecular dynamics simulations are adopted to model the lubricant outflow process from the pore of the PI material. Coarse-grained models are constructed to investigate the lubricant migration behaviors with different rotation speeds, rotation radii, and pore sizes. The results show that a lubricant within the pore fails to outflow due to the capillary effect in a static state. However, for the rotating pores, if the centrifugal forces resulting from rotation exceed the capillary forces, the lubricants will begin to flow out. Furthermore, the lubricant in the large pore is easier to outflow due to the smaller capillary force, which is the main mechanism of lubricant outflow from the pores.

Optimized pyrolytic synthesis and physicochemical characterization of date palm seed biochar: unveiling a sustainable adsorbent for environmental remediation applications.

This study focuses on the optimization and comprehensive characterization of biochar synthesized from date palm seeds (DPS), a prevalent agricultural waste in arid regions. Using response surface methodology (RSM) with a central composite design (CCD), we optimized the pyrolysis process by investigating the effects of time (1-3 h) and temperature (600-900 °C) on critical properties such as specific surface area, pore volume, and yield. The optimized biochar, produced at 828 °C for 1.7 h, demonstrated a high specific surface area of 654.8 m2/g and well-developed microporosity. Characterization techniques, including XRD, FTIR, SEM-EDS, and BET analyses, revealed an amorphous carbon structure with graphitic domains, diverse surface functionalities, and a heterogeneous porous microstructure. The biochar's point of zero charge at pH 7.58 indicates its potential for selective adsorption of charged contaminants. The close agreement between RSM-predicted and experimental values for specific surface area (652.1 m2/g vs. 654.8 m2/g) and micropore volume (0.191 cm3/g vs. 0.190 cm3/g) validates the effectiveness of the model in optimizing biochar properties. This research highlights the potential of DPS-derived biochar as a sustainable adsorbent for environmental remediation, opening avenues for valorizing agricultural wastes and contributing to circular economy principles.

Evaluation of calcium looping CO2 capture and thermochemical energy storage performances of different stabilizers promoted CaO-based composites derived from solid wastes

Calcium looping is considered as an important high-temperature cyclic CO2 capture and concentrated solar energy storage technology. However, the dramatic inactivation of CaO over multiple carbonation-calcination cycles has seriously restricted their practical applications. In this study, a series of metal oxide (i.e. TiO2, MgO, Al2O3 and ZrO2)-stabilized CaO-based materials with high cyclic stability derived from carbide slag were synthesized via a facile and cost-effective approach for simultaneously enhanced CO2 capture and thermochemical energy storage (TCES). The results suggest that CCS-H-TiO2 exhibits high initial CO2 uptake of 0.41 gCO2/gsorbent, superior cyclic stability with an average attenuation of 1.71 %/cycle and remarkably stable energy storage density. CCS-H-Al2O3 shows the best stability with lowest attenuation rate of 9.6 %. Except for CCS-H-MgO, the stabilizers reacted with active calcium to form new phases and used as physical “barrier” and high-TT skeleton to offset the sintering stress, retain the microporous structures, hinder the excessive agglomeration and alleviate sintering.

Nanoscale Biochar for Fertilizer Quality Optimization in Waste Composting: Microbial Community Regulation

Conventional composting faces challenges of nitrogen loss, product instability, and limited humic substance formation. This study investigated the effects of nanoscale biochars (nano-BCs) derived from rice straw (nano-RSB) and corn stover (nano-CSB) on manure composting. A randomized design with five treatments was used: control, regular biochars (RSB and CSB), and nano-BCs. Nano-BCs, especially nano-CSB, significantly improved compost maturity and reduced phytotoxicity, achieving a 146.20 % germination index. They increased total nitrogen (55.09–63.64 %) and phosphorus (10.25–12.33 %) retention, reduced NH4+-N loss, and promoted nitrification. Nano-CSB showed the highest final NO3−-N content (8.63 g/kg). Bacterial richness and diversity increased by 25–30 % in nano-BC treatments, with selective enrichment of beneficial species. The unique properties of nano-BCs, including high surface area and microporous structure, improved nutrient retention and compost quality. Nano-BCs offers a promising solution for sustainable waste management and high-quality compost production in agriculture, significantly enhancing nutrient retention and microbial community regulation during composting process.

Sound absorbers from walnut shell waste: measurement and models

Waste walnut shells have been cleaned, dried, chopped, glued, pressed, and molded to form porous cylinders for measurement of normal incidence sound absorption coefficient spectra in an impedance tube. Porosities and flow resistivities have been measured non-acoustically. Field Emission Scanning Electron Microscopy images, used to obtain fragment size for determining shell density, reveal that the fragment surfaces are rough, which may influence acoustical performance. Measured absorption spectra have been compared with predictions of two analytical models for acoustical properties of rigid porous media, which assume microstructures of identical uniform parallel slanted slits (SS) and non-uniform cylindrical pores with a log normal radius distribution (NUPSD) respectively. Measured values of flow resistivity and porosity are used in the models but tortuosity is adjusted to give best agreement with the quarter wavelength resonance in the measured absorption coefficient spectra. Predictions agree best with data for samples made from the smallest shell fragments. These samples have the highest values of tortuosity, flow resistivity and offer good absorption at speech frequencies which suggests that recyclable and sustainable sound absorbers made from walnut shell wastes could be useful for controlling indoor reverberation..