Effects Of Different Activation Methods Research Articles

Design, preparation, and performance of marine resource-based alkali-activated cementitious materials

The construction of islands and reefs and marine engineering cannot depend on cementitious materials, and how to utilize marine resources to prepare cementitious materials is the key to realizing the convenient construction of marine engineering. In this paper, starting from the necessary composition for the formation of gels, the effects of different activation methods on their activities were investigated by utilizing coral and diatomite as calcium and silicon sources, respectively. The study results show that using calcined coral to activate calcined diatomite resulted in a 28 days strength of up to 2.89 MPa, but it was not processable. The precursor with volcanic ash can be prepared by co-calcining coral and diatomite under lower temperature conditions, and its calcination temperature needs to be no less than 800 °C. In addition, characterization by XRD, FTIR, SEM and BET showed that increasing the calcination temperature helps to form more active substances with volcanic ash, such as CaO, CaSiO3, and Ca2SiO4, which can improve the compressive strength of alkali-activated materials prepared from them. The highest strength growth rate of 3.03 % and 28 days compressive strength of 10.80 MPa were obtained when the co-calcined temperature was 850 °C. The results of this study can provide some reference for the development of marine resource-based cementitious materials.

Study on accelerating activation of recycled hardened concrete powder based on microbial induced calcium precipitation

The CO2 atmosphere in the flue gas of cement kiln was simulated in this paper, and different methods were used to activate the RHCP with particle size < 75 µm under normal temperature and pressure. The effects of different activation methods were studied, and the mechanism of CO2 storage was clarified. On the basis of concrete carbonization curing, a new technology based on MICP was proposed. During the activation of RHCP, a Bacillus strain capable of secreting carbonic anhydrase was introduced into the CO2 carbonization system of RHCP. Carbonic anhydrase could accelerate the capture and conversion of CO2 into bicarbonate ions and carbonate ions. Calcite-type CaCO3 and amorphous silica gel were formed by the reaction of CO2 with active components in RHCP. Finally, the generated product filled the pores to make the microstructure of the slurry denser, and CO2 was also permanently sealed. The results showed that the MM-RHCP not only improved the activity index of the mortar, but also improved the potential for storing CO2 in RHCP. Through FT-IR, XRD, SEM-EDS, TGA and nitrogen adsorption pore size analysis, it was further proved that the use of microbial mineralized RHCP could accelerate the formation of CaCO3, ettringite and SiO2·n H2O. In addition, the CO2 storage capacity of MM-RHCP was greater than that of DC-RHCP and LP-RHCP. The RHCP after mineralization treatment could replace cement as mineral admixture, and this technology realized the resource utilization of solid waste. At the same time, CO2 was permanently fixed in RHCP. Therefore, it provided a new way for deep carbon sequestration in the cement industry.

Textural characteristics of activated carbons prepared from agricultural residues‐review

AbstractAgricultural residues are the most available biomass resources in the world and can be exploited to produce various activated carbons at low cost. The textural properties of activated carbon, including surface area, pore size, pore size distribution, and certain surface functionalities are the main factors in the application of bio‐based electrode materials for energy storage devices and electrochemical catalyst for CO2 reduction reactions, gas adsorption and separation, in water and wastewater treatment. This paper reviews the physical characteristics of activated carbons produced from various biomass resources using different methods. The effects of different activation methods, sources of biomass, and other parameters on the surface properties such as specific surface area and pore volume of activated carbon are discussed. The differences in the characteristics of activated carbon made from different agricultural biomass resources under the same parameters are evaluated. Eventually, the application of abundant agricultural residues for fabricating supercapacitors' electrode materials is also discussed.

Research Progress on the Application of Biomass-Based Porous Carbon Materials in Lithium Battery Electrode

With the growth of the world population, limited non-renewable energy sources, oil and coal mine are becoming increasingly exhausted. The long-term consumption of fossil energy not only causes an energy crisis, but also makes ecological and environmental problems more significant. Therefore, lithium batteries, as an energy storage tool, have been studied by a number of researchers due to their advantages such as high specific energy, little environmental pollution and long cycle life. For secondary batteries, the performance of electrode materials affects the development of batteries. Biomass-derived porous carbon materials have the advantages of cheap, easy-to-obtain from raw materials, large specific surface area, many pore structures, strong electrical conductivity, adjustable pore structure, and have been widely concerned in recent years and used as electrode materials for energy storage lithium batteries application. In the process of charging and discharging lithium batteries, porous carbon materials can provide more space for lithium ions to be embedded and removed from the electrode, improving the capacity and thus the efficiency of the battery. In this paper, the main preparation technology of biomass-derived carbon materials and the improvement technology of heteroatom doping are reviewed. The application effects of different activation methods on the porous carbon materials prepared by plant materials in the negative electrode of lithium battery are compared, and the performance of the materials in practical application is evaluated in the paper, which provides reference materials for the beginners of using biomass structure to prepare porous carbon materials.

Effect of different activation methods on the intratubular penetration of CaOH2 paste: Ex-vivo analysis by confocal laser scanning microscopy.

The aim of this study was to evaluate the maximum penetration depth (MPD) and penetration area (PA) of CaOH2 paste agitated by different methods and to measure the pH after performing these methods. Fifty-five mandibular premolars were divided into control, GL and 4 experimental groups, GEC, GXP, GEDDY and GI (n= 11), where the paste was agitated with Easy Clean, XP-endo Finisher, EDDY and Irrisonic, respectively. The canals were instrumented and irrigated with NaOCl. The paste was manipulated with propylene glycol and rhodamine B dye. Root sections were examined using confocal laser scanning microscopy. There was no difference between groups regarding PA (p> 0.05). At 5 mm, MPD was greater in GEC than in GL or GEDDY, and greater in GI than in GL (p< 0.05). At 2 mm, MPD was greater in GEC than in the other groups (p< 0.05). In conclusion, both Easy Clean and Irrisonic promoted deeper paste penetration and were associated with higher pH levels.

Activated carbon from hydrolysis lignin: Effect of activation method on carbon properties

This study presents the effects of different activation methods to produce activated carbon from the hydrolysis lignin. Pretreatment of the feedstock with common mineral acids (HCL, HNO3, and H3PO4), different steam rates for physical activation, and different chemical activating agents (ZnCl2, Na2CO3, and KOH) for chemical activation were investigated. The pretreated biomass was carbonized and activated in one-stage process and the surface characteristics, such as total pore volume, pore size distribution and specific surface area, were investigated. The results showed that the activated carbon surface properties were not greatly affected by acid pretreatment. Brunauer-Emmett-Teller (BET) surface areas as high as 616 m2/g could be achieved with physical activation and 2054 m2/g with chemical activation. Different steam rates in the selected interval (0.5–2 cm3/min) did not change the pore size distribution but had small positive effect on the specific surface area, while chemical activation with ZnCl2 increased the mesoporosity, and activation with KOH increased the microporosity and oxygen groups in the form of ether and alcohol bonds.

Solving two environmental problems simultaneously: Scalable production of carbon microsheets from structured packing peanuts with tailored microporosity for efficient CO2 capture

Highly porous carbon microsheets (CMS) were prepared by the bulk carbonization and activation of waste packing peanuts, and applied to CO2 capture and release. Two different activation methods, physical activation using CO2 and chemical activation using KOH, were used for the preparation of porous CMS, and the effects of different activation methods were compared. Chemical activation functioned better than the physical activation, successfully producing highly microporous carbon structures with higher carbon yield. Textural properties such as specific surface area and total pore volume increased proportionally to the mass ratio of KOH/carbon because of the development of the porous structure and enlargement of pore size through KOH activation. Among the samples prepared, the highest CO2 adsorption capacities of 6.51 mol kg−1 at 0 °C and 4.07 mol kg−1 at 25 °C were obtained at 1 bar in the packing-peanut-derived CMS prepared with a KOH/carbon ratio of 3 (CMS-K3). It is noteworthy that the CO2 adsorption uptake was significantly dependent on the volume of narrow micropores of pore sizes less than 0.8 nm rather than the specific surface area or total pore volume. CMS-K3 also exhibited excellent cyclic stability, good CO2/N2 selectivity, fast adsorption kinetics, and low heat of adsorption, being regarded as a promising adsorbent for CO2 capture.

CO2 and CH4 Adsorption Behavior of Biomass-Based Activated Carbons

The aim of the present work is to study the effect of different activation methods for the production of a biomass-based activated carbon on the CO 2 and CH 4 adsorption. The influence of the activation method on the adsorption uptake was studied using three activated carbons obtained by different activation methods (H 3 PO 4 chemical activation and H 2 O and CO 2 physical activation) of olive stones. Methane and carbon dioxide pure gas adsorption experiments were carried out at two working temperatures (303.15 and 323.15 K). The influence of the activation method on the adsorption uptake was studied in terms of both textural properties and surface chemistry. For the three adsorbents, the CO 2 adsorption was more important than that of CH 4 . The chemically-activated carbon presented a higher specific surface area and micropore volume, which led to a higher adsorption capacity of both CO 2 and CH 4 . For methane adsorption, the presence of mesopores facilitated the diffusion of the gas molecules into the micropores. In the case of carbon dioxide adsorption, the presence of more oxygen groups on the water vapor-activated carbon enhanced its adsorption capacity.

Effects of processing on the mineralogy and solubility of carbonate-rich clays for alkaline activation purpose: mechanical, thermal activation in red/ox atmosphere and their combination

Abstract The present study focuses on the assessment of the effects of different activation methods on carbonate-rich clays, to understand the mineralogical differences originated and to exploit such information to industry for traditional and innovative applications, especially as a precursor for alkali activated binders. Illite carbonate-rich clay samples were subjected to thermal activation in ox/red atmosphere between 400 and 900 °C, mechanical activation (grinding for 5, 10 and 15 min) and to a combination of such treatments. Mineralogical and textural changes in the activated samples were evaluated through X-ray powder diffraction, Fourier transform infrared spectroscopy and thermal techniques. The activated samples with the highest content of amorphous phase underwent leaching tests in a 3 M NaOH solution by means of inductively coupled plasma-mass spectrometry. The application of the three processing routines, yielded three types of activated clays with different leaching modes of Si, Al, K and Ca: (1) high energy grinding preferentially delaminates clay minerals and reduces the grain size of calcite. K leaching reaches the highest values; (2) thermal heating at 800 °C increases relatively the Si/Al solubility ratio, but the absolute concentrations of these elements are equal or lower than those obtained from ground clays. The relatively higher leaching of Ca is influenced by the formation of non-stoichiometric and poorly crystalline Ca-silicates and -aluminosilicates; (3) high energy grinding combined with heating treatment yields an extended amorphisation, mainly at the expense of clay minerals, with the highest leaching of Si and Al, and the lowest of Ca. New formed K-feldspars inhibit the concentration of K in alkaline solution.

Electrokinetic delivery of persulfate to remediate PCBs polluted soils: Effect of different activation methods.

Persulfate-based in-situ chemical oxidation (ISCO) for the remediation of organic polluted soils has gained much interest in last decade. However, the transportation of persulfate in low-permeability soil is very low, which limits its efficiency in degrading soil pollutants. Additionally, the oxidation-reduction process of persulfate with organic contaminants takes place slowly, while, the reaction will be greatly accelerated by the production of more powerful radicals once it is activated. Electrokinetic remediation (EK) is a good way for transporting persulfate in low-permeability soil. In this study, different activation methods, using zero-valent iron, citric acid chelated Fe(2+), iron electrode, alkaline pH and peroxide, were evaluated to enhance the activity of persulfate delivered by EK. All the activators and the persulfate were added in the anolyte. The results indicated that zero-valent iron, alkaline, and peroxide enhanced the transportation of persulfate at the first stage of EK test, and the longest delivery distance reached sections S4 or S5 (near the cathode) on the 6th day. The addition of activators accelerated decomposition of persulfate, which resulted in the decreasing soil pH. The mass of persulfate delivered into the soil declined with the continuous decomposition of persulfate by activation. The removal efficiency of PCBs in soil followed the order of alkaline activation > peroxide activation > citric acid chelated Fe(2+) activation > zero-valent iron activation > without activation > iron electrode activation, and the values were 40.5%, 35.6%, 34.1%, 32.4%, 30.8% and 30.5%, respectively. The activation effect was highly dependent on the ratio of activator and persulfate.

Generation of parthenogenetic goat blastocysts: effects of different activation methods and culture media

The present study was carried out to investigate the effects of different activation methods and culture media on the in vitro development of parthenogenetic goat blastocysts. Calcium (Ca2+) ionophore, ethanol or a combination of the two, used as activating reagents, and embryo development medium (EDM), modified Charles Rosenkrans (mCR2a) medium and research vitro cleave (RVCL) medium were used to evaluate the developmental competence of goat blastocysts. Quantitative expression of apoptosis, stress and developmental competence-related genes were analysed in different stages of embryos. In RVCL medium, the cleavage rate of Ca2+ ionophore-treated oocytes (79.61 ± 0.86) was significantly (P < 0.05) higher than in ethanol (74.90 ± 1.51) or in the combination of both Ca2+ ionophore and ethanol. In mCR2a or EDM, hatched blastocyst production rate of Ca2+ ionophore-treated oocytes (8.33 ± 1.44) was significantly higher than in ethanol (6.46 ± 0.11) or in the combined treatment (6.70 ± 0.24). In ethanol, the cleavage, blastocyst and hatched blastocyst production rates in RVCL medium (74.90 ± 1.51, 18.30 ± 1.52 and 8.24 ± 0.15, respectively) were significantly higher than in EDM (67.81 ± 3.21, 14.59 ± 0.27 and 5.59 ± 0.42) or mCR2a medium (65.09 ± 1.57, 15.36 ± 0.52 and 6.46 ± 0.11). The expression of BAX, Oct-4 and GlUT1 transcripts increased gradually from 2-cell stage to blastocyst-stage embryos, whereas the transcript levels of Bcl-2 and MnSOD were significantly lower in blastocysts. In addition, different activation methods and culture media had little effect on the pattern of variation and relative abundance of the above genes in different stages of parthenogenetic activated goat embryos. In conclusion, Ca2+ ionophore as the activating agent, and RVCL as the culture medium are better than other tested options for development of parthenogenetic activated goat blastocysts.

Synthesis and properties of PdO/CeO2-Al2O3 catalysts for methane combustion

This study focuses on the loading of catalytic materials, e.g., palladium on the surface of supporting materials, with the aim to obtain catalysts with high activity for methane combustion. The catalyst PdO/CeO2-Al2O3 was prepared by impregnation under ultrasonic condition. The effect of different activation methods on the activity of catalysts for methane catalytic combustion was tested. The properties of reaction and adsorption of oxygen species on catalyst surface were characterized by H2-temperature programmed reduction (H2-TPR), and O2-temperature programmed desorption (O2-TPD). Furthermore, the sulfur tolerance and sulfur poisoning mode were investigated. The results indicate that the catalyst PdO/CeO2-Al2O3 activated with rapid activation shows higher activity for methane combustion and better sulfur tolerance. The result of sulfur content analysis shows that there is a large number of sulfur species on the catalyst’s surface after reactivation at high temperature. It proves that the activity of catalysts cannot be fully restored by hightemperature reactivation.

Zona-free and with-zona parthenogenetic embryo production in goat ( Capra hircus) — effect of activation methods, culture systems and culture media

Studies on parthenogenetic activation of oocytes are important to improve the efficiency of nuclear transfer as artificial activation of oocytes is an essential component of nuclear transfer protocol. The present study was carried out to investigate the effects of different activation methods, culture systems and culture media on in vitro development of zona-free and with-zona parthenogenetic embryos in goat. In case of zona-free parthenogenesis, there was a significant (p < 0.05) increase in cleavage rate and blastocyst yield when oocytes were activated by electrical pulse (76.29 ± 0.52% and 19.07 ± 0.39% respectively) than when Ca-ionophore was used for activation (63.45 ± 0.73% and 14.09 ± 0.65% respectively). The quality of blastocysts was evaluated by determination of cell number and by expression profile of pluripotent related gene Oct-4. No significant (p < 0.05) difference was found in quality of blastocysts produced by different activation methods. In culturing of zona-free parthenogenetic embryos, flat surface (FS) was proved to be the best system. A significant (p < 0.05) decrease in cleavage rate and blastocyst yield was found in Microdrop culture of zona-free embryos (43.67 ± 2.08% and 0.72 ± 0.72% respectively) in comparison to WOW of zona-free embryos (73.88 ± 1.70% and 15.51 ± 1.34% respectively) and FS of zona-free (75.14 ± 0.81% and 23.93 ± 2.71% respectively) as well as with-zona (72.16 ± 1.55% and 18.16 ± 0.68%) embryos. Zona-free flat culture system yielded significantly (p < 0.05) higher blastocyst rate than zona-free WOW system as well as with-zona flat culture system. The zona-free and with-zona parthenogenetic embryos were cultured in three different media — Research Vitro Cleave media from Cook® Australia (RVCL), Embryo Development Medium (EDM) and Modified Synthetic Oviductal Fluid (mSOF). In case of zona-free parthenogenesis, significant (p < 0.05) increase was found in blastocyst development rate in RVCL medium (18.61 ± 1.52%) than EDM (11.29 ± 0.77%) or mSOF (11.53 ± 1.86%). In case of with-zona parthenogenesis, RVCL medium and EDM were found superior to mSOF. The results of the study will be helpful to improve the efficiency of nuclear transfer in goat.

Preparation of activated carbon microspheres from phenolic resin with metal compounds by sub- and supercritical water activation

Activated carbon spheres with well-developed mesopores and high mechanical strength were prepared from phenolic resin with a metal catalyst using sub- and supercritical water (SCW) as an activating agent. A rare earth metal chloride (cerous chloride) was used as catalyst. The effects of different activation methods on the porosity and adsorption characteristics of carbon spheres were investigated. All samples were characterized by nitrogen adsorption at 77 K. Results showed that the catalyst could promote the development of pores in SCW. The cerium compound facilitated the development of mesopores with preponderant pore sizes at 4 nm and 7 nm. The catalyst affected the porosity of the porous carbon the most, whereas the effect of the activation methods was secondary. The activation pressure had the least effect.

Effect of Sperm Extract Injection Volume, Injection of PLCζ cRNA, and Tissue Cell Line on Efficiency of Equine Nuclear Transfer

We evaluated the effect of different activation methods on blastocyst development after equine nuclear transfer. All activation treatments were followed by incubation in 2 mM 6-dimethylaminopurine for 4 h. In Experiment 1, reconstructed oocytes were injected with sperm extract for 0.1, 0.2, 0.4, 0.8, or 1.6 sec using a FemtoJet injection device, then treated with ionomycin. The blastocyst rate (9.8%) for 0.1-sec injection was significantly higher than that for 0.2 sec (0%) or 0.8 sec (1.4%). In Experiment 2, injection of murine PLCzeta cRNA before or after ionomycin treatment did not increase blastocyst development (0 and 4.5%) over a control treatment (injection of sperm extract after ionomycin exposure; 5.6%). Transfer of 10 blastocysts produced in Experiments 1 and 2 resulted in five pregnancies, all lost before 70 days of gestation. In Experiment 3, cells from a second biopsy sample from the same horse produced significantly more blastocysts than did the original sample (4/44 vs. 0/58; p < 0.05). Transfer of these four blastocysts produced two viable foals. In Experiment 4, blastocyst development rates did not differ between oocytes in metaphase I or II at the time of nuclear transfer (16.7 and 3.0%, respectively). A healthy foal was produced from a blastocyst originating from a metaphase I oocyte.

Effects of activation methods and culture conditions on development of parthenogenetic porcine embryos

The effects of different activation methods and culture conditions on early development of porcine parthenotes were examined. Three different activation methods were tested: (1) electroporation; (2) electroporation followed by incubation in the presence of butyrolactone I, an inhibitor of cdc2 and cdk2 kinases; and (3) electroporation followed by a treatment with cycloheximide, a blocker of protein synthesis. The activated oocytes were cultured in two different media, NCSU-23 and PZM-3 under 5% CO 2 in air. In a separate experiment, the effects of high (∼20%) or low (5%) O 2 tension on early embryo development were also evaluated. The average pronuclear formation was less ( p < 0.05) in the electroporated oocytes (83.9 ± 1.7%) compared with those activated by electroporation and butyrolactone I or electroporation plus cycloheximide (92.8 ± 0.8 and 93.0 ± 1.0%). In PZM-3 medium, the average frequencies of blastocyst formation (59.7 ± 3.6%) and hatching (10.6 ± 1.3%) were greater than those in NCSU-23 medium (39.9 ± 3.1% blastocyst formation, p < 0.05; and 0.2 ± 0.2% hatching; p < 0.001). Furthermore, the average nuclear number was also greater ( p < 0.001) in blastocysts developed in PZM-3 (50.2 ± 1.3) than in those developed in NCSU-23 (35.3 ± 1.1). Blastocyst formation was similar ( p > 0.10) among the three activation procedures when parthenotes were cultured in NCSU-23, while in PZM-3 more ( p < 0.05) parthenotes produced by electroporation plus butyrolactone or electroporation plus cycloheximide developed into blastocysts compared to electroporation alone (64.9 ± 5.2 and 68.6 ± 3.5% compared with 45.6 ± 4.7%). Incidences of apoptotic nuclei were similar ( p > 0.10) among all treatments. No difference in development was found between parthenotes that developed under high versus low O 2 tension ( p > 0.10). These results demonstrate that activation methods targeting the calcium signaling pathway at several points trigger embryonic development more efficiently than electroporation alone. The data also imply that the PZM-3 medium provides for enhanced culture conditions for the early development of parthenogenetic porcine embryos than NCSU-23.