Micropore Content Research Articles

Macroscopic mechanical behavior and microstructural evolution of compacted loess in the Chinese Loess Plateau

Understanding the mechanical behavior of compacted loess is of great significance to engineering construction on the Loess Plateau. To gain an in-depth knowledge of the variations in compressibility, shear strength and microstructure of compacted loess at different dry densities and water contents, a series of macro and microscopic tests were carried out on the loess samples, including oedometer compression tests, direct shear tests and scanning electron microscope imaging. The pore properties of loess in microscopic images were investigated using the particle (pores) and cracks analysis system. The relationship between pore microscopic indicators and mechanical parameters was explored by multivariate statistical analysis. The results show that the compression coefficient of compacted loess decreases with increasing dry density, of which trend is more significant at high water content. Both cohesion and internal friction angle decrease with increasing water content, but the former is more sensitive to changes in soil moisture. Besides, the evolution sequence of compacted loess structure is basically overhead-mosaic-flocculation with the increase of compactness and saturation. The difference is that with the compaction, the pores in the loess sample change from macropores into mesopores and then to small pores, and the directional distribution and morphological complexity of the pores weakens; while with the humidification of the loess sample, small pores and macropores transform into mesopores, and the pores are more oriented and more complex in shape. During this process, the micropore content changes are weak. Moreover, mesopores content and pore fractal dimension have a positive effect on compressibility, while micropores content and orientation probability entropy have a positive effect on shear strength.

Investigation on effect of EVA on properties of desert sand-based permeable materials

This paper aims at studying the effect of adding ethylene vinyl acetate (EVA) emulsion on the properties of desert sand-based permeable materials and explore the modification effect and mechanism of polymers. EVA emulsion can improve the fluidity of the slurry, and significantly improve the compressive strength, water permeability and freezing resistance at 10 % content. The EVA emulsion cured film is adsorbed on the surface of anhydrous cement particles. At the same time, the ester group in emulsion reacts with Ca2+ following hydrolysis, which inhibits the early hydration process of cement and reduces the early heat release. However, it has a non-significant impact on the later-age hydration and ensures the strength development of cement at the later stage. The emulsion can affect the pore structure of the material and can significantly increase the micropores content at 10 % content. The physical and chemical actions of polymer together influence the hydration process of cement and improve the bonding between desert sand and cement paste.

Flexible preparation of nanoporous SiO2 aerogel as novel adsorbent for efficient adsorption of Zearalenone

Zearalenone (ZEN) is a form of mycotoxin in the animal feed that is a carcinogen causing pathological changes after entering animal and human body. In the paper, SiO2 aerogels were prepared using sol-gel method adopting atmospheric pressure drying, vacuum drying and combustion drying. The aerogels were characterized and subjected to assess the sorption potential of ZEN. It was found that the atmospheric pressure drying aerogel (ADSA) had the highest surface area and micropore content, while the vacuum drying aerogel (VDSA) was completely mesoporous with the smallest surface area. The combustion drying aerogel (CDSA) was also dominantly mesoporous with fractional micropores. The ZEN equilibrium adsorption capacity for ADSA was the highest while its adsorption rate was the lowest. The adsorption rate of VDSA was the highest, while its equilibrium adsorption capacity was significantly lower than ADSA. The adsorption capacities of VDSA and CDSA were of comparable magnitude owing to the similarity in pore structure. The adsorption isotherms and kinetics were modeled with semiempirical theoretical models. The ZEN adsorption process of all the aerogels was governed by both physisorption and chemisorption. Experimental result suggested a flexible option of SiO2 aerogels as promising low cost absorbent for ZEN removal.

Simplified Method of Estimating the A300 Micropore Content in Air-Entrained Concrete

It is well known that the most important parameters for predicting the frost resistance of pavement concrete are the air pore spacing factor, L, and the micropore content, A300. The A300 parameter requires complex calculations with the estimation of the air-void size in a 3D space. The procedure is based only on one-dimensional chord lengths. The air-void distribution is used only to determine the content of micropores and has no other practical application. Based on the results of the analysis, it was found that there is a simpler way to estimate the A300 parameter without the tedious calculations described in the EN 480-11 Standard. The presented approach is based on the existing linear correlation between the A300 parameter and the number of chords in 28 length classes. The developed function includes only a few coefficients (eight classes) because only chord lengths of 10-350 µm are statistically significant. This fact is important not only for the simplification of calculations but may also have consequences for the methodology of testing parameters characterizing the structure of air-entrained concrete using the 2D method. The presented function allows the estimation of A300 with a standard error not exceeding 0.02%, so it is useful for practical use.

Influence of coalification on pore structure evolution in middle-ranked coals

The influence of coalification on coal structure evolution in middle ranked coals is significant for physical assessment of coalbed methane (CBM) reservoirs, which provides insights on the intrinsic connection between coalification jump and pore heterogeneity. A total of 26 middle-ranked coals were samples covering Liupanshui Coalfield in Guizhou Province, Anhe Coalfield in Henan Province, Huaibei Coalfield in Anhui Province, Sanjiang Basin in Heilongjiang Province, Ordos Basin in Shaanxi Province and Qinshui Basin in Shanxi Province. Based on a series of experiments including vitrinite reflectance, coal maceral identification, nitrogen adsorption and the pore fractal method, the inner link between physical property parameters of coal reservoirs and coal rank was revealed. The results show that the coal maceral in middle rank coals is dominated by vitrinite and inertinite and two types of adsorption pores are divided according to the nitrogen adsorption/desorption curves along with pore size distribution. The specific surface area is positively correlated with total pore volume, micropore volume and negatively correlated with averaged pore size and transitional pore volume. The coal samples with low average pore sizes have relatively high total pore volume, specific surface area and micropore volume per unit nm. With the increase of coal rank, the fluctuating points of micropore and transitional pore volume correspond to 1.16%–1.19%, 1.41%–1.43% and 1.86%–1.91% of Ro, max, respectively. The boundary of Ro, maxcorresponding to the second coalification jump can be more specifically defined as 1.16%–1.19% from the established nominal range of 1.1%–1.3%. The pore fractal dimension DNA1and DNA2increase with increasing specific surface area. Furthermore, the DNA2has a negative correlation with micropore volume and averaged pore size, indicating that the coal with smaller average pore diameter and lower micropore content has a more complex pore structure.

Catalysts for ORR Based on Silver-Modified Graphene Oxide and Carbon Nanotubes

The main obstacle to the widespread dissemination of fuel cells is the high cost, so researchers are actively searching for ways to replace the expensive platinum catalyst with cheaper analogs. In this paper we studied the Ag- and Pd-containing carbon catalysts based on carbon nanotubes and graphene oxide. The study of the textural characteristics of the catalysts showed that the greatest specific surface area has a catalyst based on MWCNT containing 10% silver, all synthesized catalysts are mainly mesoporous, and the content of micropores is insignificant. Raman spectroscopy and SEM data indicate a significant change in the structure of the modified carriers compared to pure MWCNT and GO. An electrochemical experiment was performed and linear voltammetric diagrams were obtained and compared with the voltammetric diagrams obtained on the platinum catalyst. GO_Ag 10% and MWCNT_Ag 10% Pd 10% are closest in the values of kinetic parameters in both kinetic and diffusion regions. GO_Ag 10% has the highest initial potential Eonset = −0.145 V and MWCNT_Ag 10% Pd 10% has the highest half-wave potential E½ = −0.23 V. The studied catalysts have characteristics comparable to those presented in the literature.

Co-precipitation reaction: A facile strategy for designing hierarchical porous carbon nanosheets for EDLCs and zinc-ion hybrid supercapacitors

Hierarchical porous carbon is a valuable electrode material for electrochemical energy storage devices by virtue of its high specific surface area, excellent conductivity, and large pore volume. Herein, a simple, convenient and cheap self-made Fe-based template strategy is innovated to prepare hierarchical porous carbon employing coal chemical byproducts anthracene as carbon precursor, which is utilized as electrode materials of electrical double layer capacitors (EDLCs) and zinc ions hybrid supercapacitors (ZHSs). Benefiting from the high specific surface area (2085.1 m2 g−1), feasible micropore content (0.28 cm3 g−1), suitable oxygen content (11.57 at%) and two-dimensional nanosheet structure, the optimal sample delivered a high specific capacitance value of 183.5 F g−1 at 0.05 A/g and excellent rate capability (109.5 F g−1 at 20 A/g) for symmetric supercapacitor. Meanwhile, the as-fabricated ZHSs exhibited remarkable specific capacitance (181.67 mAh/g at 0.05 A/g), superior energy density (145.2 Wh kg−1), high power density (14.5 kW kg−1) and splendid cycling stability (∼91.25 % after 40,000 charge/discharge cycles at 2 A g−1). This work affords a new idea for the synthesis of template carbon using a feasible and low-cost co-precipitation reaction route and has great significance for the development of high-performance electrochemical energy storage device.

THE INVESTIGATION OF THE POROUS STRUCTURE OF CARBON SORBENTS BASED ON β-CYCLODEXTRIN FOR USE IN ENVIRONMENTAL PROTECTION TECHNOLOGIES

In this paper, the porous structure of three types of β-cyclodextrin (β-CD) carbons was synthesized and investigated. The first carbon was obtained from pure β-CD, the second carbon was synthesized from β-CD using the KOH activator, and the third carbon was synthesized from pure β-CD with additional ultrasonic treatment in the non-cavitation mode at the last stage. It was found that the carbon from pure β-CD has a micromesoporous structure with a small specific surface area (~35 m2/g). Activation with KOH causes a significant increase in the specific surface area (~654 m2/g) due to an increase in the content of micropores with an average size of 1,25 nm. The ultrasonic treatment causes mechanical grinding and oxidation of the carbon surface. It has been shown that such treatment increases the mesopore content and significantly changes the mesopore size distribution. It has been established that the oxidation of the β-CD carbon surface after ultrasonic treatment causes an increase in its hydrophilicity of up to 83,1%. The increase in hydrophilicity will allow more efficient use of synthesized carbon and composites based on it in solving the problems of environmental safety in water environments.

A hydrophobic and hierarchical porous resin-based activated carbon modified by g-C3N4 for toluene capture from humid conditions

The synthesis of hydrophobic and hierarchical porous activated carbon (AC) used for toluene capture from a humid atmosphere still remains a challenge. In this work, a novel hydrophobic and hierarchical porous AC was prepared from resorcinol-formaldehyde resin spheres using g-C3N4 as a new pore-forming agent. By the proper participation of g-C3N4, the obtained adsorbent GNHRC-1.5 was endowed with an excellent toluene adsorption capacity (10 mmol/g) under low pressure of P = 0.2 kPa, which was 54% higher than that of nonmodified resin-based AC. By DIH (Difference of Isosteric Heats) prediction, the adsorption selectivity of GNHRC-1.5 to toluene/water was further enhanced to 139.55, higher than that of other reported adsorbents. Toluene breakthrough tests and kinetic analysis showed that GNHRC-1.5 possessed a faster intraparticle diffusion and outstanding reusability, which was ascribed to its a certain amount of mesopores. Grand Canonical Monte Carlo and molecular dynamics simulation were applied to explore the competitive adsorption mechanism of toluene and water vapor from the perspective of pore size and surface functional groups. The results indicated that the competitive adsorption was controlled by Van der Waals energy, intramolecular energy and electrostatic energy. Both the higher content of narrow micropores below 1 nm and carboxyl are not beneficial for toluene adsorption under humid conditions. For GNHRC-1.5, an appropriate micropore distribution, a certain amount of mesopores, and a lower content of oxygen functional groups, afford it excellent adsorption selectivity for toluene and fast adsorption kinetics under humid conditions.

Semi-interpenetrating anion exchange membranes using hydrophobic microporous linear poly(ether ketone)

In order to realise high ionic conductivity and improved chemical stability, a series of anion exchange membranes (AEMs) with semi-interpenetrating polymer network (sIPN) has been prepared via the incorporation of crosslinked poly(biphenyl N-methylpiperidine) (PBP) and spirobisindane-based intrinsically microporous poly(ether ketone) (PEK-SBI). The formation of phase separated structures as a result of the incompatibility between the hydrophilic PBP network and the hydrophobic PEK-SBI segment, has successfully promoted the hydroxide ion conductivity of AEMs. A swelling ratio (SR) as low as 12.2 % at 80 °C was recorded for the sIPN containing hydrophobic PEK-SBI as the linear polymer and crosslinked structure with a mass ratio of PBP to PEK-SBI of 90/10 (sIPN-90/10(PEK-SBI)). The sIPN-90/10(PEK-SBI) AEM achieved the highest hydroxide ion conductivity of 122.4 mS cm−1 at 80 °C and a recorded ion exchange capacity (IEC) of 2.26 meq g−1. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) clearly revealed the improved phase separation structure of sIPN-90/10(PEK-SBI). N2 adsorption isotherm indicated that the Brunauer-Emmett-Teller (BET) surface area of the AEMs increased with the increase of microporous PEK-SBI content. Interestingly, the sIPN-90/10(PEK-SBI) AEM showed good alkaline stability for being able to maintain a conductivity of 94.7 % despite being soaked in a 1 M sodium hydroxide solution at 80 °C for 30 days. Meanwhile, a peak power density of 481 mW cm−2 can be achieved by the hydrogen/oxygen single cell using sIPN-90/10(PEK-SBI) as the AEM.

Self-templating synthesis of porous carbon with phytate salts for supercapacitor application

Zinc phytate was synthesized as a self-sacrificing template to prepare porous carbon for supercapacitor with the starting materials of phytate acid and zinc acetate. The obtained carbon material possesses a hierarchically porous structure with pore size distributed at 1 and 10 nm, contributing to a specific surface area of 1125 m2 g−1 according to the nitrogen sorption analysis. Moreover, the porous structure can be effectively adjusted by introducing KOH during the preparation procedure of phytate salt, resulting in a significant increase of micropore content. The absence of KOH signal in the X-ray diffraction pattern of carbon precursor and uniform K, Zn distribution in carbon precursor indicate the formation dual-metal phytates and contributing to the micropore for the prepared porous carbon by in-situ K activation instead of KOH activation. With developed microporosity, the specific capacitance can be promoted up to 294 from 195 F g−1 in KOH electrolyte and 247 from 187 F g−1 in H2SO4 electrolyte. Our findings provide a guide to prepare porous carbon with tunable porosity through a facile self-templating method.

Effect of the pore structure of coal-based activated carbon and hydrogen addition on methane decomposition for the preparation of carbon nanotubes

Activated carbon with a hierarchical micro/mesoporous carbon structure was synthesized using Shenmu coal as the raw material, which was impregnated with KOH (K) in different K/C ratios before carbonization at various temperatures. The obtained material was loaded with nickel and then employed as catalyst for the catalytic methane decomposition (CMD) to prepare carbon nanotubes. Using a constant nickel loading, the effects of the pore structure of the different activated carbon materials and hydrogen addition on the preparation of carbon nanotubes were investigated. The results show that the coal-based activated carbon with a micropore content of 0.8, synthesized at a carbonization temperature of 850 °C and a K/C ratio of 2, is the most suitable carrier for the methane cracking catalyst to produce carbon nanotubes. The diameter of the prepared carbon nanotubes is in the range of 50–120 nm with a length of 5–15 μm. The addition of hydrogen can prevent the high-temperature decomposition of oxygen-containing functional groups, and the activity of the catalyst can be maintained by inhibiting carbon deposition. Furthermore, the hydrogen present in the CMD process can promote the formation of carbon nanotubes with larger diameters (50–350 nm) and shapes. The nanotubes are more curved, and their length is reduced to 5–11 μm. Finally, the formation mechanism of carbon nanomaterials is discussed according to the morphological changes of the products after hydrogen addition and the existing theories. In conclusion, appropriate amounts of oxygen-containing functional groups and larger micropore volumes facilitate the pyrolysis of coal-based activated carbon catalysts in the preparation of carbon nanotubes.

Preparation of microporous carbonaceous CO2 adsorbents by activating bamboo shoot shells with different chlorides: Experimental and theoretical calculations

In this paper, a series of microporous carbonaceous adsorbents were prepared using bamboo shoot shells as carbon precursors and four different chlorides (calcium chloride, potassium chloride, iron chloride and zinc chloride) as activators. The results show that the pore structure and specific surface area of the adsorbent jointly affect the adsorption capacity of CO2. The porous carbon prepared with calcium chloride and potassium chloride as the activator has the highest micropore content, reaching more than 93 %. The solid adsorbent BSSC-CaCl2-700 with calcium chloride as the activator exhibited the highest CO2 adsorption capacity of 70.45 cm3/g and 53.62 cm3/g at 273 K and 298 K under 1 bar, respectively. It is a promising adsorbent for CO2 capture from flue gas. Based on the experimental study, a model of porous carbon prepared by different activators was developed. Combined with the mechanism of CO2 adsorption in porous materials, the binding adsorption energy and self-diffusion coefficient of porous carbon prepared by the different chlorides as activators were calculated by DFT method. The results show that the adsorption energy of porous carbon with calcium chloride as an activator is − 8.1 KJ/mol, and the self-diffusion coefficients are 8 × 10−7 and 1.3 × 10−7 at 273 K and 298 K, respectively. The fitted R2 was both greater than 0.95. Therefore, the selected model can better illustrate that chloride has a stronger effect on the preparation of microporous biomass carbon, which provides an idea for subsequent experiments and theoretical research.

Pore development and mechanical properties of iced concrete during hydration

High geothermal temperature is a key problem that restricts the mining of mineral resources. In order to maintain the normal production of deep mines, we must seek a new stope cooling method that is more green, economic and efficient. Based on this, this paper proposes a iced concrete technology applied to the cooling of deep mine mining, and focused on the mechanical strength, pore structure, heat transfer evolution law, hydration reaction process and other change characteristics of concrete with different initial ice content (0 %, 10 %, 20 %, 30 %, 40 %, 50 %, 60 %). Finally, the pore structure and mechanical properties of iced concrete in the hydration process were analyzed and studied. The results demonstrate that (1) for concrete specimens cured for 1 d, the mechanical strength of iced concrete decreases slightly with an increase in initial ice content. After 28 d of curing, the mechanical strength is positively correlated with the initial ice content; (2) the porosity of macropores and mesopores of iced concrete is negatively correlated with the compressive strength, whereas the microporous porosity of iced concrete is positively correlated with the compressive strength because macropores and mesopores primarily undertake compression fracture penetration during dissipation, and micropores can be conducive to elastic strain energy accumulation; (3) the temperature change trend of iced concrete rises first and then decreases with the inflection point at 24 h. With an increase in the ice content in iced concrete, the initial temperature drops and the heating time is delayed. Therefore, in the initial hydration reaction stage, owing to the cooling effect of ice particles, an increase in the initial ice content decreases the content of hydration reaction products of concrete, increases the content of harmful pores such as macropores and mesopores, and relatively reduces the content of micropores; at 28 d, because the ice particles enhance the water-storage capacity of the concrete, an increase in the initial ice content leads to a more intense hydration reaction at the later stage and better pore structure distribution, which improves the final mechanical strength of the concrete.

Design of highly microporous activated carbons based on walnut shell biomass for H2 and CO2 storage

Low-cost walnut shell-based carbons with high microporosity were prepared by simple one-step carbonization with chemical activation using KOH, exhibiting the promising potential to be a very good CO2 and H2 adsorbent. The physicochemical properties of the obtained carbons were characterized by N2 and CO2 adsorption isotherms, X-ray powder diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and elemental analysis. The activated carbon AC-800 was characterized by a highly developed specific surface area of 1868 cm2/g and a high micropore content of 0.94 cm3/g. It highly exhibited CO2 uptake in 1 bar was up to 9.54, 5.17, 4.33 mmol/g for 0, 25 and 40 °C, respectively. In addition, the H2 storage capacity was 3.15 mmol/g at 40 bars. Significantly, confirmed an exceptionally high dependency of CO2 and H2 uptake vs micropores structure of activated carbon. AC-800 also shows good selectivity for CO2/N2 and fast adsorption kinetics that be easily regenerated with superior cyclic stability after multiple cycles The experimental isotherm data of activated carbon produced from walnut shells were analyzed using Langmuir, Freundlich, Temkin, Sips, and Toth isotherm equations. The fitting details showed that the multitemperature Toth equation is a powerful tool to mathematically represent CO2 and H2 isotherms on activated carbon. The easy way of preparation and high capture abilities endow this kind of activated carbon attractive as a promising adsorbent for CO2 and H2 storage.

Nitrogen-Rich Porous Organic Polymers with Supported Ag Nanoparticles for Efficient CO2 Conversion.

As CO2 emissions increase and the global climate deteriorates, converting CO2 into valuable chemicals has become a topic of wide concern. The development of multifunctional catalysts for efficient CO2 conversion remains a major challenge. Herein, two porous organic polymers (NPOPs) functionalized with covalent triazine and triazole N-heterocycles are synthesized through the copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC) reaction. The NPOPs have an abundant microporous content and high specific surface area, which confer them excellent CO2 affinities with a CO2 adsorption capacity of 84.0 mg g−1 and 63.7 mg g−1, respectively, at 273 K and 0.1 MPa. After wet impregnation and in situ reductions, Ag nanoparticles were supported in the NPOPs to obtain Ag@NPOPs with high dispersion and small particle size. The Ag@NPOPs were applied to high-value conversion reactions of CO2 with propargylic amines and terminal alkynes under mild reaction conditions. The carboxylative cyclization transformation of propargylic amine into 2-oxazolidinone and the carboxylation transformation of terminal alkynes into phenylpropiolic acid had the highest TOF values of 1125.1 and 90.9 h−1, respectively. The Ag@NPOP-1 was recycled and used five times without any significant decrease in catalytic activity, showing excellent catalytic stability and durability.

Lotus Root‐Derived Porous Carbon as an Anode Material for Lithium‐Ion Batteries

AbstractWhen being used as anodes for lithium‐ion batteries (LIBs), environmental friendly and easily available biomass‐derived carbon materials often suffer from complex preparation conditions, underdeveloped pore structures and relatively low circulation capacities. In this context, three novel biomass‐derived porous carbon materials including LRK‐6, LRK‐7 and LRK‐8 sourced from lotus roots are activated and carbonized by a simple method. The prepared material has a three‐dimensional honeycomb structure. The effects of carbonization temperature on the structure, morphology and electrochemical properties of the material are investigated in detail. Owing to its high specific surface area (831.017 m2 g−1), appropriate microporous content (0.217 cm3 g−1) and the highest mesopore capacity (0.325 cm3 g−1) together with suitable doping of N and O atoms, the as‐optimized LRK‐7 material shows a reversible specific capacity of 725.25 mAh g−1 after 100 cycles at 0.1 A g−1 and 614.60 mAh g−1 after 223 cycles at 0.3 A g−1. Besides, LRK‐7 material also exhibits high rate performance, achieving a capacity of 153.5 mAh g−1 at 9.0 A g−1. The results verify that the application of LRK‐7 as a potential anode material in the LIB will embrace a bright future.

Influence of Chemical Treatment on the Spectral and Thermal Behavior of Activated Carbon Obtained from Olive Oil Solid Waste

Solid waste remained after the extraction of oil from olive oil fruits (OOSW), was used to obtain active carbon depending on chemical activation using H3PO4, KOH and ZnCl2 as activating agents. The changes in composition due to chemical treatment and pyrolysis were investigated by chemical analysis, spectral (IR), and thermal analysis (DTA). Thermodynamic parameters of formation (activation energy (ΔEa*), enthalpy change (ΔH*), entropy change (ΔS*) and free energy change (ΔG*) related to the thermal decomposition process were calculated. Adsorption of both iodine and methylene blue at very low concentrations were done, the quantity of the iodine adsorbed (iodine number) indicated the micropores content of carbon by the uptake of iodine from the solution. It is equivalent to surface area of carbon between 900m2/g and 1100 m2/g. To characterize activated carbons as well as determining the adsorption capacity adsorption of methylene blue was done.

Synthesis of Hierarchically Ordered Porous Silica Materials for CO2 Capture: The Role of Pore Structure and Functionalized Amine

Hierarchically ordered porous silica materials (HSMs) with a micro/mesoporous structure were successfully prepared with the sol-gel method using dextran, dextran/CTAB, and CTAB as templates. The obtained hierarchically structured silica was successfully modified with amine groups through post-grafting and one-pot methods. Their architectural features and texture parameters were characterized by XRD, N2 adsorption–desorption isotherms, SEM, TEM, FTIR, and TGA techniques. The results demonstrated that the pore structure depended on the reaction temperature and the amount of CTAB added in the synthesis procedure. A series of porous silica with hierarchical pore structures possessed abundant micropores, ordered mesopores, and a tunable surface area and pore volume. After modification, the ordered structure of the hierarchical porous silica almost disappeared due to the presence of amine groups in the pore channel. Furthermore, to explore the effect of pore structures and amine groups on CO2 adsorption performance, before and after amine modification of HSMs, adsorbents were evaluated regarding the capacity of collecting CO2 for comparison. According to these results, the varying microporous content, pore size distribution, and density of the amine groups were important factors determining the capacity of CO2 capture.

Study on the recycling of ceramic polishing slag in autoclaved aerated foam concrete by response surface methodology

In this study, the mechanical performance and thermal insulation properties of autoclaved aerated foam concrete (AAFC) with ceramic polishing slag (CPS) were investigated using chemical foaming technology at a density of 500 kg/m3. An orthogonal experimental array and the response surface methodology analysis were used to optimize the mix proportion of CPS slurry, cement, and lime content, and XRD, SEM, TG, and MIP were employed to study the microstructure and composition of the AAFC. The AAFC with the maximum compressive strength, minimum thermal conductivity, and cement consumption was obtained using the quadratic model of the response surface methodology analysis. The minimum thermal conductivity reached 0.1032 W/m·K, and a compressive strength value of 4.03 MPa was obtained for the mixtures with the CPS slurry, cement, and lime at 2804, 226.2, and 234 kg/model, respectively. The results of the microstructure development show that with an increase in CPS slurry, the compressive strength is significantly enhanced. This might be due to a sufficient hydration reaction with a proper water content. The Si and Al in the CPS react with the calcareous material and C–S–H gels to form tobermorite, thus promoting the compressive strength. In addition, the MIP indicates that the micropore (10–50 mm) content of the AAFC has a significant correlation with thermal conductivity, while macropores (>500 mm) have a significant relationship with compressive strength.