Pore Size Distribution Measurements Research Articles

Moisture Properties, Microstructural and Microbiological Characteristics of Flax and Hemp Shives Used in Construction Industry

ABSTRACT The construction industry is among the largest energy-consumer and waste-generating sectors, and it needs sustainable methods and materials to decrease its carbon footprint. One possible solution is to use secondary raw materials and crops as a basis for thermal insulation materials or passive buffers of moisture. This article presents the results of testing raw hemp and flax shives obtained from Polish crops for use in the construction industry. There are only a few works devoted to the parameters of the raw material itself, and no comparative studies are available on the shives themselves. Therefore, it is of utmost importance to compare the properties of shives obtained from these two fibrous plants, to understand their usability and possibilities. Our research focuses on measuring pore size distribution, hygroscopic sorption moisture, capillary rise, and contact angle. It was shown that both types of shives are characterized by similar porosity and hygroscopic sorption characteristics, but different pore size distribution and ability to absorb water through capillary action. Microbiological tests showed variations in the presence of fungi on the shives surfaces. The article also presents an example of the use of the tested materials as an internal wall covering and compares it to gypsum plaster.

Study on the Effects of Fe Doping on C‐ZFe Catalyst for Catalytic Removal of NO from the Low‐Temperature Flue Gas

AbstractThe denitrification efficiency of carbon‐based zero valent iron catalyst (C‐ZFe) for low‐temperature selective catalytic reduction (SCR) (<140°C) highly depends on the structural species of iron oxide (FexOy) and the physicochemical properties of the catalyst. In the study, we investigated the main factors affecting the low‐temperature denitrification efficiency of C‐ZFe such as temperature, iron content and O2. The results showed that the average NOX conversion was 72.6 % at 135°C when the space velocity was 459 h−1 and the mass ratio of carbon to iron was 15 % to 85 %. The surface morphology and structure of C‐ZFe were characterized by the surface area and pore size distribution measurements, X‐ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR) and X‐ray photoelectron spectroscopy (XPS). The results indicated that the iron on the catalyst surface was oxidized by O2 to Fe2O3, which could retain NO and then formed intermediate products. NO entered the mesoporous structure along C‐ZFe surface and proceeded a catalytic reduction reaction with the adjacent carbon.

A novel framework for deriving water retention behavior of multimodal unsaturated soils based on pore size distribution data

AbstractThe soil water retention curve (SWRC) strongly influences the hydro-mechanical properties of unsaturated soils. It plays a decisive role in geotechnical and geo-environmental applications in the vadose zone. This paper advances a novel framework to derive the water retention behavior of multimodal deformable soils based on the pore size distribution (PSD) measurements. The multiple effects of suction on the soil pore structure and total volume during SWRC tests are considered. The complete picture of soil microstructure is quantitatively described by the void ratio (for the pore volume) and a newly defined microstructural state parameter (for pore size distribution) from a probabilistic multimodal PSD model. Assuming a reversible microstructure evolution, a unique PSD surface for wetting and drying links the SWRC and PSD curves in the pore radius-suction-probability space. A closed-form water retention expression is obtained, facilitating the model's implementation in particle applications. The model is validated using the water retention data of four different soil types, showing a strong consistency between the measurement and the reproduced curve. The proposed method provides new insights into the pore structure evolution, the water retention behavior and the relationship between them for multimodal deformable soils.

Biomechanical and physical properties selection of Ti-Ha-CaCO<sub>3</sub> biocomposite prostheses for replacement of bone atrophy

Traditional prosthetic materials often lack the desired properties to mimic the mechanical behaviour of natural bone, leading to complications and reduced implant longevity. This study aims to conduct a biomechanical and physical properties selection analysis for biocomposite prostheses' suitable for replacing bone atrophy. This involves evaluating the mechanical properties of developed biocomposites with different structures (dense, porous and gradient) to ensure compatibility with the mechanical properties of bone. The radar chart was adopted to compare and evaluate the mechanical strength of various biocomposite implants and identify the most suitable prosthesis for load-bearing bone replacement. The study utilises powder metallurgy, scanning electron microscopy (SEM), and ImageJ software to produce and characterise the pore size distribution of the biocomposites, respectively. The findings of this study revealed the gradient and porous biocomposites exhibited desired mechanical properties with porosity of 20.67 and 27.72 % pore size up to 134 and 256 μm, compressive strength of 174 and 149.29 MPa and compressive modulus of 30.42 and 28.3 GPa respectively. The SEM analysis, coupled with pore size distribution and porosity percentage measurements, offers valuable information for designing and fabricating biomaterials with enhanced properties. The gradient biocomposite was identified to be the best sample for load-bearing bone replacements by the selection analysis because of its high compressive strength and low modulus, which is within the established cortical bone mechanical properties.

Quantification of overcompensated cations in layer-by-layer membrane by Orange yellow II

The charge density of the nanofiltration (NF) membrane separation layer is critical for ion separation because the charge-based Donnan exclusion plays a critical role. To quantified the charge density has been an important but difficult task. We recently discovered the excellent performance of poly(styrene sulfonate) (PSS)/ poly (allylamine hydrochloride) (PAH) layer-by-layer (LBL) NF membranes for Mg2+/Li+ separation. The overcompensated amine groups (R-NH3+) in PAH were assumed to be the main contribution, but lacked a quantification of the charge density for further proof. Here, a simple quantitative experimental method by Orange yellow II staining was reported for the first time to measure the overcompensated amine groups in the separation layer. The sulfonic acid group (R-SO3-) in Orange yellow II stoichiometrically adsorbed to the excessive R-NH3+ at pH = 3 by electrostatic interaction, and desorbed at pH = 12. Thermodynamics and kinetics analysis of the sorption process demonstrated a Langmuir monolayer sorption and the sorption was controlled by sorption reaction not diffusion. The pore size distribution and rejection measurement confirmed that Orange yellow II sorption did not disrupt the original PSS/PAH layer. A linear relationship was observed between the charge density and the coating bi-layers or PAH layers. The accurate, easy assessment of charge density of LBL NF membrane provides future possibility for understanding overcompensation during LBL assembly and a bottom-up understanding of the charges to the NF performance in separation.

Pore size distribution measurement with magnetic resonance [formula omitted] distributions outside the fast diffusion regime

Based on Brownstein-Tarr (BT) theory, a new method is proposed to determine the pore size distribution which is an important petrophysical property in studying fluid storage and fluid transport in reservoir rocks. For reservoir rocks with large pores, or high surface relaxivity, direct conversion from the magnetic resonance (MR) T2 distribution with the fast diffusion assumption may be unreliable. In this study, the ground mode lifetime T20 distribution was proposed to be utilized to estimate the pore size distribution. The T20 lifetime of large pores within a porous system can be determined directly through experiment. However, the T20 lifetimes of smaller pores may overlap with the first nonground mode T21 lifetimes of the larger pores, which collectively contribute to the MR signal with a shorter lifetime. To accurately determine the T20 lifetime of smaller pores, it is essential to remove the contribution to the distribution of the T21 lifetimes of the larger pores. The T21 distribution can be both experimentally observed and calculated through the proposed method. The proposed pore size distribution method is verified by calculation in the present work. Water-saturated glass bead packs were employed for initial experiments. The calculated pore size, and its distribution, match the geometric pore size. The proposed method was applied to determine the pore size distribution of a Berea sandstone. The results are in good agreement with SEM measurements.

Various waste polystyrene for useful membrane fabrication: Comparative experimental study

Plastic waste recycling is drawing great attention to prevent the harmful effects resulting from the accumulation of plastic waste, especially as an integrated waste-to-product process. This study introduced a comparative study of two polystyrene (PS) wastes for polymeric membrane fabrication. Two types of polystyrene wastes, transparent and white-coloured, used for yoghurt packaging, were utilized. The commercial PS membrane was also fabricated for comparison. Polystyrene membranes were prepared by a non-solvent induced phase separation (NIPS) method. The prepared membranes were characterized by Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), measurements of contact angle (CA), porosity, and pore size distribution. According to the results, the prepared membranes showed an asymmetric structure with a blocked skin layer. Also, the prepared membrane surfaces were partially hydrophilic. Increasing polymer concentration (from 10 to 18 wt.%) enhanced the structural homogeneity of the membrane by obtaining smaller pores. On the other hand, the membranes' porosity decreased with the rise in the polymer concentration. Measurements highlighted the successful fabrication of similar membrane characteristics using two types of PS wastes, making them vivid candidates for water desalination and gas separation applications.

Digitally Based Precision Time-Domain Spectrometer for NMR Relaxation and NMR Cryoporometry

NMR Relaxation (NMRR) is an extremely useful quantitative technique for material science, particularly for studying polymers and porous materials. NMR Cryoporometry (NMRC) is a powerful technique for the measurement of pore-size distributions and total porosities. This paper discusses the use, capabilities and application of a newly developed compact NMR time-domain relaxation spectrometer suitable for studying both solid and liquid samples (Mk3 NMR Relaxation spectrometer & Cryoporometer, Lab-Tools (nano-science), Ramsgate, Kent, UK. (2019)). This highly compact precision NMR Spectrometer is based on a Field Programmable Gate array (FPGA) module and custom surface mount low-noise NMR receiver and NMR linear transmitter. A high proportion of the RF circuitry is in a digital form, implemented as firmware in the FPGA, which gives the instrument an excellent long-term stability. It also includes an on-chip Linux computer. The FPGA module is credit-card sized, and both the NMR receiver and NMR transmitter are even smaller. The software, including the top-level NMR pulse sequence definitions, are written in an array processing language, Apl. The spectrometer comes complete with a Graphical User Interface (GUI) for control and on- and offline curve fitting and data analysis. The recent development of the Lab-Tools Peltier thermo-electrically cooled NMR variable-temperature (V-T) probe that cools the sample below −60 °C is also discussed. This Peltier cooling gives the precision temperature control and smoothness needed by NMR Cryoporometry (10 mK near the probe liquid bulk melting point). This enables the NMRC measurement of pore-size distributions in porous materials, for the unusually wide pore-size range of sub-nano to over 1 micron-sized pores. The NMR Spectrometer’s unusually small size, ability to measure solids, low noise and high performance make it particularly suitable for material science studies both in the field and in university, research institute, company and even school laboratories. A human portable version now exists. Use of the controlling GUI is described, and results from example NMR Relaxation and NMR Cryoporometric measurements are given.

Vapour-Phase Selective Hydrogenation of γ-Valerolactone to 2-Methyltetrahydrofuran Biofuel over Silica-Supported Copper Catalysts.

2-Methyltetrahydrofuran (MTHF) is a desirable biomass-based platform chemical with excellent potential as an ideal biofuel, green solvent, and raw material for synthesizing downstream chemicals. In this work, a series of copper nanoparticles encapsulated on SiO2 were prepared by the wet impregnation method and evaluated as efficient non-noble metal catalysts for the vapour-phase hydrogenation of γ-valerolactone (GVL) to MTHF in a fixed-bed reactor under mild reaction conditions. The obtained catalyst properties were determined by XRD, FE-SEM, TEM, UV-DRS, TPR, NH3-TPD, N2O decomposition and pore size distribution measurements. Meanwhile, the parameters/variables tuning their catalytic performance (activity, conversion, selectivity and stability) were examined. Various Cu loadings featured on the SiO2 support are essential for tuning the catalytic activity. Among the catalysts tested, a 5 wt% Cu/SiO2 catalyst showed a 97.2% MTHF selectivity with 71.9% GVL conversion, and showed a stability for 33 h time-on-stream, achieved at 260 °C and atmospheric pressure conditions. It was found that a huge dispersion of Cu metal in support, hydrogen activation ability, abundant acidic sites and surface area are all beneficial for improved MTHF selectivity.

Microstructure and moisture transport in carbonated cement-based materials incorporating cellulose nanofibrils

Carbonation of cement-based materials may lead to durability problems, so that it is necessary to find a way to reduce the effect of carbonation on concrete durability. This study investigated the effects of cellulose nanofibrils (CNFs) on the durability of carbonated cement-based materials. Two dosages of CNFs were used to prepare cement pastes and mortars. Before and after accelerated carbonation (4 % CO2 concentration and 57 % relative humidity), their microstructure, mineralogical composition, moisture retention capacity, drying kinetics, and water absorption were measured. Results show that the contents of hydration products (CH, C-S-H, and ettringite) slightly decrease with the increase of CNFs dosage. After carbonation, the carbonation ratios of hydration products decrease with CNFs dosage so that more hydration products remain in the carbonated materials. The calcite content was found to increase with the dosage of CNFs which may help the transformation of other metastable calcium carbonates to calcite. The coarsening effect of carbonation on pore structure was clearly observed in measured pore size distribution for all materials, while our results show that this effect is weakened by CNFs. Moisture transport is clearly accelerated by carbonation, but the acceleration rate is diminished with the increasing dosage of CNFs, suggesting that CNFs are able to reduce the microstructural damage by carbonation.

Development of poly(vinyl alcohol)/β-cyclodextrin/P(MVE-MA) composite nanofibers as effective and selective adsorbent and filtration material for the removal and separation of cationic dyes from water

The preparation of new smart adsorbent and filtration materials has a great importance for the adsorption and filtration studies. In this study, for the effective adsorption of cationic Basic Yellow 2 (BY2) dye from water and for the selective separation of anionic dye from the anionic and cationic dye mixture solution, a new water-insoluble negatively charged poly(vinyl alcohol) (PVA)/β-cyclodextrin/poly(methyl vinyl ether-alt-maleic anhydride) (P(MVE-MA)) nanofiber membrane was fabricated by using simple electrospinning technique and thermal cross-linking process. The obtained nanofiber composite membrane material was characterized by FTIR, water solubility, mechanical property, SEM, BET specific surface area and pore size distribution measurements. After cross-linking process, maximum tensile stress and Young's modulus of membrane material showed an enhancement from 1.59 MPa to 2.58 MPa and from 66.67 MPa to 146.75 MPa, respectively. For cationic BY2 dye, membrane material exhibited an excellent adsorption capacity value of 2.554 × 10−3 mol g−1 or 775.98 mg g−1. In addition, it did not adsorb anionic Acid Blue 74 (AB74) dye. Kinetic and isotherm data of BY2 followed the pseudo second order and Langmuir models, respectively. For BY2 dye, membrane material displayed a good regeneration performance during the five adsorption/desorption cycles. In the filtration of anionic and cationic dye mixture, PVA/β-cyclodextrin/P(MVE-MA) nanofiber membrane material exhibited a remarkable separation efficiency (99.33%) and showed selective adsorption ability toward cationic BY2 dye. In brief, the fabricated membrane material is of a promising application in the water treatments and separation studies.

Engineering properties and pore structure of lightweight aggregates produced from off-spec fly ash

• High- and low-calcium off-spec fly ash based lightweight aggregate (LWA) was produced. • Engineering properties and pore structure of LWA was characterized. • Small dose of NaOH as fluxing agent can result in off-spec fly ash based LWA with desired engineering properties. This study characterizes the engineering properties of lightweight aggregate (LWA) manufactured from low calcium (F-FA) and high calcium (C-FA) waste fly ash that were designed using a previously-developed thermodynamics-guided process. LWA properties that were characterized include specific gravity, vacuum water absorption, water absorption over time, water desorption, porosity, pore size distribution, and permeability. The LWA studied had a low oven dry specific gravity ranging from 1.22 to 1.45. The vacuum absorption and total open porosity of F-FA LWA decreased as the fluxing agent (NaOH) concentration increased while the values for C-FA LWA varied with increasing amounts of fluxing agent. All LWA passed the ASTM C1761 water absorption/desorption requirements for application to the internal curing of concrete. X-ray computed tomography (XCT) and dynamic vapor sorption analyzer (DVSA) techniques were used to characterize the LWA pore structure. It was found that for F-FA LWA the normalized porosity, counting only pores smaller than 50 nm (gelpores + mesopores), ranged from 4 % to 11.5 %, while for C-FA LWA, this same pore size range had porosity ranging from 1.7 % to 2.8 %. Pore size distribution measurements of F-FA LWA using XCT showed that the pores became larger and the predicted permeability coefficient increased as the fluxing agent concentration increased. For C-FA LWA, the predicted permeability increased with increasing NaOH concentration. Since the pore size distribution had greater variability and did not follow a specific increasing trend, the increase in C-FA permeability could only be due to an increase in pore connectivity.

Ultra-Selective CMSMs Derived from Resorcinol-Formaldehyde Resin for CO2 Separation.

A resorcinol-formaldehyde precursor was synthesized to fabricate the CO2 selective Carbon Molecular Sieve Membranes (CMSMs) developed in this study. The degree of polymerization (DP) was analyzed via Gel Permeation Chromatography (GPC) and its effect on the CO2/N2 perm-selectivity and CO2 permeance was investigated. The membrane that was polymerized at 80 °C (named R80) was selected as the best performing CMSM after a preliminary test. The post treatment with oxidative atmosphere was performed to increase the CO2 permeance and CO2/N2 perm-selectivity on membrane R80. The gas permeation results and Pore Size Distribution (PSD) measurements via perm-porometry resulted in selecting the membrane with an 80 °C polymerization temperature, 100 min of post treatment in 6 bar pressure and 120 °C with an oxygen concentration of 10% (named R80T100) as the optimum for enhancing the performance of CMSMs. The 3D laser confocal microscopy results confirmed the reduction in the surface roughness in post treatment on CMSMs and the optimum timing of 100 min in the treatment. CMSM R80T100 exhibiting CO2/N2 ideal selectivity of 194 at 100 °C with a CO2 permeability of 4718 barrier was performed higher than Robeson’s upper bound limit for polymeric membranes and also the other CMSMs fabricated in this work.

Carbon-based zero valent iron catalyst for NOX removal at low temperatures: performance and kinetic study.

In order to solve the problem of nitrous oxide (NOX) removal at low temperatures, the carbon-based zero valent iron (C-ZFe) catalyst was prepared and studied. According to the kinetic study and the obtained kinetic parameters, the De-NOX reactor was designed to provide information for industrial applications. The box-behnken experimental design (BBD) was used to study the performance of C-ZFe, and the optimized operating parameters were obtained as the temperature was 408.15K, the catalyst bed height was 140cm (the space velocity was 459h-1), the concentration of NO was 550ppm, under which the NOX conversion was 72.7%. A kinetic model based on Langmuir-Hinshelwood (L-H) and Mars Van Krevelen mechanism was used to describe the kinetics for the reduction of NO by C-ZFe at low temperatures. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), surface area and pore size distribution measurements, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) results supported the validity of the model proposed. The gas-solid catalytic kinetic process of NO removal by C-ZFe was a quasi-first-order kinetic reaction, the apparent activation energy was 41.57kJ/mol, and the pre-exponential factor was 2980min-1.

Fabrication of a molecularly imprinted monolithic column via the epitope approach for the selective capillary microextraction of neuropeptides in human plasma

A novel molecularly imprinted monolithic (MIM) column was designed and fabricated using the epitope approach, and was used for the selective capillary microextraction (CME) of the neuropeptides neurotensin (NT) and neuromedin N (NmN). The MIMs were synthesized in a capillary by thermally initiated polymerization of the functional monomer (methacrylic acid (MAA)), in the presence of a dummy template (Pro-Tyr-Ile-Leu (PYIL)), a crosslinker and porogens. The resulting monoliths were characterized by scanning electron microscopy, pore size distribution measurement, and Fourier transform infrared spectroscopy. Different synthesis conditions of the MIM column were investigated. The parameters affecting the MIM-CME performance, including loading, washing and elution protocols, were optimized as well. The MIMs were used to enrich NT and NmN from human plasma prior to HPLC-UV analysis. The imprinted monolith showed an excellent maximum adsorption capacity of 245–711 mg mL−1 and selectivity (imprinting factor of 5.7–13.4) towards its target peptides. Low detection limits of 0.62 and 1.20 nM, and satisfactory recoveries (82.5–98.8%) were obtained for NT and NmN, respectively. The proposed MIM-CME/HPLC-UV method was found suitable to be used as an effective tool for the highly efficient and specific analysis of NT and NmN in human plasma samples.

Is early drying shrinkage still determined by the mesopore content? A case study of cement paste with minerals

Long-term drying shrinkage is deemed to be relevant with the mesopore content of cement paste, so is early drying shrinkage still determined by the number of mesopores? This was not the case. Through combining the measurement of water loss and pore size distribution (PSD), this study provides an explanation of early-age drying shrinkage of cement paste with different types/contents of minerals (i.e., blended cement paste) added, and a corresponding prediction model was proposed in terms of its early shrinkage. The results show that during hydration, instead of the mesopore content, the water loss due to evaporation in capillary pores of cement paste was well correlated with its early drying shrinkage, which could be attributed to a small portion of mesopores rather than all mesopores have lost water at an early age. Meanwhile, a parameter rs, which was defined as the radius of the pores where the meniscus formed, was calculated by combining the results of PSD and water evaporation, and its reduction led to an increment of drying shrinkage of specimens. Finally, the outcomes obtained from the proposed prediction model fitted well with experimental data, revealing the effectiveness and accuracy of the model in foreseeing early drying shrinkage of blended cement paste.

Spatial heterogeneity analyses of pore structure and mineral composition of Barnett Shale using X-ray scattering techniques

The spatial heterogeneity of pore structure and mineral composition at μm to mm scales in mm to cm-sized shale samples complicates the laboratory measurements of porosity & pore size distribution and consequently reservoir quality evaluation. Traditional fluid invasion characterization methods typically take hours to days to get data and can only test relatively small samples (usually 2.54 cm diameter core plugs and mm-sized rock chips). The X-ray scattering techniques at the Advanced Photon Source of the Argonne National Laboratory have the capability to non-destructively determine the pore structure and mineral composition of mm × mm area in a short time of seconds and to hold several to hundreds of mm2 sized sample to conduct large area heterogeneity analysis in the short duration of hours. With the use of ultra-small angle X-ray scattering (USAXS), small-angle X-ray scattering (SAXS), and wide-angle X-ray scattering (WAXS), the porosity, surface area and pore size distribution of two Barnett Shale samples have been mapped out and the mineral compositions are determined qualitatively. Overall, the porosity and pore surface area of the Barnett Shale Sample A over a 36 cm2 area ranges from 1.70 % to 8.13 % and 8.87 m2/g to 40.2 m2/g respectively. The porosity and surface area of Sample B over a 24 cm2 area varies from 3.15 % to 11.7 % and 18.3 m2/g to 60.2 m2/g. In Sample A, the mineral composition shows a shift from carbonate-rich to siliciclastic-rich over a distance of several millimeters. For Sample B, the mineral compositions are mainly siliciclastic and do not show an obvious lithological change. The direct observations of high spatial heterogeneity of pore structure and mineral composition in shale illustrate the utility of integrated X-ray scattering techniques to provide valuable insights into shale studies and reservoir evaluation.

An integrated pore size distribution measurement method of small angle neutron scattering and mercury intrusion capillary pressure

Small-angle neutron scattering and high-pressure mercury intrusion capillary pressure testing are integrated to analyze the pore size distribution of the broad sense shale oil reservoir samples of the Permian Lucaogou Formation in the Jimsar Sag, Junggar Basin, China. The results show that, compared with the measurement method integrating gas adsorption and mercury intrusion, combination of small-angle neutron scattering and mercury intrusion can more accurately characterize full-scale pore size distribution. The full-scale pore size distribution curve of the rock samples in the study area includes two types: the declining type and submicron pore-dominated type. The declining type is mainly found with silty mudstone and dolomitic mudstone, and most of its pores are smaller than 80 nm. Silt-fine sandstones and dolarenite are mostly of the submicron pores-dominated type, with most pores smaller than 500 nm. They also present large specific pore volumes and average pore diameters of macropores and are the favorable lithogenous facies for development of high-quality reservoirs.

Bituminous Coal Char-Derived Hard Carbon As a Low-Cost Anode Material for Sodium-Ion Batteries

Increasing demands in the global energy markets for large-scale electric energy storage systems have made it essential to improve current rechargeable battery technologies. Due to the high price and low safety of current commercial lithium-ion batteries, as well as potential resource limitations of lithium, there is a need to explore alternative ion intercalation battery technologies [1]. Sodium-ion batteries (SIBs), having a theoretical energy density comparable with lithium-ion, are a promising next-generation energy storage technology to replace lithium-ion batteries in large-scale, stationary energy storage applications. A current challenge in achieving high performance SIBs is improving capacity and reducing cost of anode materials. While carbons derived from coal tar pitch have been widely studied as intercalation materials, hard carbons derived from coal char (the solid component of bituminous and sub-bituminous coals) are only recently gaining attention as SIB anode materials with surprisingly high sodium storage capacity, good rate performance, and long cycle life [2]. Bituminous coal char is used primarily as a fuel source for power production, making it an extremely low-cost electrode material. The high mineral ash content of with bituminous coal char, however, is a significant challenge to achieving high anode capacities with this material.This work investigates the effect of pyrolysis conditions and deashing parameters on the material properties and sodium-ion intercalation capacity of hard carbons derived from bituminous, SUFCO mine coal char. SUFCO coal, known as steam coal, is a local Utah coal used for power generation. Pyrolysis temperature and atmosphere, as well as acid/base washing conditions, are varied to produce anode materials with varying carbon structure and ash content. Deashing conditions explored in this work include treating raw coal char with various basic and dilute acid (10%) solutions, as well as a high concentration mixture of H2SO4:HNO3 (30:70), at different temperatures (22°C and 80 °C) and for varying times. The structure and composition of the resulting carbons are characterized via scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and pore-size distribution measurements. Electrochemical behavior is investigated by assembling coin cells (half-cells using Na metal and NaClO4 electrolyte), in a nitrogen glove box (LC Technology Solutions Inc, <0.1 ppm H2O, <0.1 ppm O2) using an MTI CR20XX coin cell press. All coin cell testing is performed using a Gamry Interface 1000E potentiostat and a Gamry four-terminal coin cell holder. The results provide insight into process-structure-performance relationships for coal char-derived hard carbons as SIB anode materials, including charge-discharge capacity, cycle life, rate performance, and electrochemical impedance.This work is supported in-part by NSF Award #1742696.[1] P. Bai, Y. He, X. Zou, X. Zhao, P. Xiong, Y. Xu, Elucidation of the Sodium-Storage Mechanism in Hard Carbons, Adv. Energy Mater. 8 (2018) 1–9.[2] Yunming Li, Yong-Sheng Hu, Xingguo Qi, Xiaohui Rong, Hong Li, Xuejie Huang, Liquan Chen, Advanced sodium-ion batteries using superior low cost pyrolyzed anthracite anode: towards practical applications, Energy Storage Materials 5 (2016) 191–197. Figure 1

Synthesis of zeolites with hierarchical porous structures using a microwave heating method

Zeolites (ZSM-5) containing mesopores with a diameter of approximately 20 nm were hydrothermally synthesized using a microwave heating method. Microwave heating promoted the generation of zeolite nanocrystals in the initial stage of the hydrothermal synthesis, and then their self-assembly formed mesopores in the interstices. The formation of mesopores in the zeolites was confirmed by carrying out their surface analysis using scanning electron microscopy, pore size distribution measurements by obtaining N2 adsorption–desorption isotherms, and dye adsorption experiments.