Decomposition Of CaCO3 Research Articles

Thermal Activation of High-Alumina Coal Gangue Auxiliary Cementitious Admixture: Thermal Transformation, Calcining Product Formation and Mechanical Properties.

In this paper, a new preparation technology is developed to make high-alumina coal gangue (HACG) auxiliary cementitious admixture by calcining HACG-Ca(OH)2 (CH) mixture. HACG powders mixed with 20 wt.% CH were calcined within a temperature range of 600-900 °C, and the thermal transformation and mineral phase formation were analyzed. The hydration reaction between activated HACG-CH mixture and cement was also investigated. The results showed that HACG experienced a conventional transformation from kaolinite to metakaolin at 600 °C and finally to mullite at 900 °C, whereas CH underwent an unexpected transformation process from CH to CaO, then to CaCO3, and finally to CaO again. These substances' states were associated with the dehydroxylation of CH, the chemical reaction between CaO and CO2 generating from the combustion of carbon in HACG, and the decomposition of CaCO3, respectively. It is the formation of a large amount of CaO above 800 °C that favors the formation of hydratable products containing Al2O3 in the calcining process and C-A-H gel in the hydration process. The mechanical properties of HACG-cement mortar specimens were measured, from which the optimal calcination temperature of 850 °C was determined. As compared with pure cement mortar specimens, the maximum 28-d flexural and compressive strengths of HACG-cement mortar specimens increased by 5.4% and 38.2%, respectively.

Silica dopant effect on the performance of calcium carbonate/calcium oxide based thermal energy storage system

The CaCO3 is being studied for its application in thermal energy storage. However, it has drawbacks of slow reaction rate during calcination and incomplete reversible carbonation which limit its use. In this paper, SiO2 has been studied as a dopant for CaCO3 to improve its cyclic performance. The CaCO3 samples were loaded with different concentrations of SiO2 and its effect on the thermal energy density of CaCO3 was determined. Afterwards, the effect of the dopant on the heat storage process of the synthesized composite along with kinetics of decarbonation reaction was investigated. Cyclic tests were performed to determine the reusability of the material. It was found that the addition of dopant helped to increase the rate of decarbonation reaction, thereby making the heat storage process more efficient as compared to pure CaCO3. The activation energy values are 255.9 kJ/mol, 280.1 kJ/mol, 244.9 kJ/mol, and 234.8 kJ/mol for 5%, 15%, 30%, and 0% doped SiO2 samples, respectively. Furthermore, thermal energy storage density increases when the amount of dopant decreases in the samples such as the 30% and 5% doped samples have gravimetric energy storage densities of 339.85 J/g and 759.24 J/g, respectively. It was observed that the large quantities (15% and 30%) of dopant had introduced a new phase of Ca3SiO5 during CaCO3 decomposition.

The influence of B doping on phase formation and microstructural evolution in NHL during solid-state reactions

Natural Hydraulic Lime (NHL), was synthesized by doping B2O3 into calcium carbonate and silica aerogel. By introducing varying levels of B3+ ion doping (0/1/5/10/15/20/25 mol%), a range of NHL compositions were successfully prepared, thereby enabling regulation of the NHL phase composition. Furthermore, through the doping of 25 mol% B3+ ions, in-depth investigations employing XRD, SEM, and FT-IR were conducted to explore phase transitions and ion migration during NHL calcination at different temperatures. Thermal analysis kinetics studies further revealed the variation of activation energies for CaCO3 decomposition and C2S crystallization with changing levels of B3+ ion doping. The introduction of B ions was observed to stabilize the α’ phase of dicalcium silicate (C2S) and moderately enhance the reactivity of calcium oxide (CaO). B3+ ions significantly influenced the crystallization mechanism of C2S, shifting it from a diffusion-controlled process to a heterogeneous nucleation process. The application of the Kissinger and Flynn-Wall-Ozawa (FWO) methods assisted in elucidating the underlying reasons for these differences. Both approaches demonstrated a substantial decrease in activation energy, signifying the pronounced influence of B doping on the sintering regime and phase transition mechanism of NHL. In summary, the precise modulation of NHL phase composition and sintering regime was achieved through B doping. These findings not only deepen our understanding of the mechanistic role of B3+ ions in NHL preparation and application but also offer robust guidance for the production process of NHL.

Nano-modulators with the function of disrupting mitochondrial Ca2+ homeostasis and photothermal conversion for synergistic breast cancer therapy

Breast cancer treatment has been a global puzzle, and apoptosis strategies based on mitochondrial Ca2+ overload have attracted extensive attention. However, various limitations of current Ca2+ nanogenerators make it difficult to maintain effective Ca2+ overload concentrations. Here, we constructed a multimodal Ca2+ nano-modulator that, for the first time, combined photothermal therapy (PTT) and mitochondrial Ca2+ overload strategies to inhibit tumor development. By crosslinking sodium alginate (SA) on the surface of calcium carbonate (CaCO3) nanoparticles encapsulating with Cur and ICG, we prepared a synergistic Ca2+ nano-regulator SA/Cur@CaCO3-ICG (SCCI). In vitro studies have shown that SCCI further enhanced photostability while preserving the optical properties of ICG. After uptake by tumor cells, SCCI can reduce mitochondrial membrane potential and down-regulate ATP production by producing large amounts of Ca2+ at low pH. Near-infrared light radiation (NIR) laser irradiation made the tumor cells heat up sharply, which not only accelerated the decomposition of CaCO3, but also produced large amounts of reactive oxygen species (ROS) followed by cell apoptosis. In vivo studies have revealed that the Ca2+ nano-regulators had excellent targeting, biocompatibility, and anti-tumor effects, which can significantly inhibit the proliferation of tumor cells and play a direct killing effect. These findings indicated that therapeutic strategies based on ionic interference and PTT had great therapeutic potential, providing new insights into antitumor therapy.Graphical

Novel high intrinsic permittivity in new perovskite ceramic GdCa2Cu3Oδ

In the present work, the GdCa2Cu3Oδ (GdCCO) compound was prepared using the conventional solid-state reaction tool, and their crystal structures and dielectric properties were systematically studied. X-ray diffraction analysis and Rietveld refinement results confirmed that GdCCO perovskite crystallizes in the tetragonal structure with the P4/mmm space group. Thermogravimetry (TG) and Differential Scanning Calorimetry (DSC) analysis confirm the decomposition of CaCO3 into calcium oxide (CaO) solid and carbon dioxide (CO2) gas at 800 °C. The composition of the grains was qualitatively examined using the EDX system attached to scanning electron microscopy (SEM). The XPS analysis was performed to investigate the oxidation state of the GdCCO perovskite elements. The frequency and temperature dependences of the complex impedance spectra and the dielectric responses of the compound GdCCO synthesized have been investigated. We first observed two semicircles conforming to grain and grain boundary responses in the impedance plots. Further, than the ambient temperature, the magnitude of the permittivity from the grain boundary (εr′ = 104 and C = 10−11 F) remains constant over most of the frequency range but decreases rapidly in the MHz frequency region. The temperature dependences of the dielectric responses show the excellent temperature stability of ε′ (Δε′=±15%), a wide temperature side (-30 – 125 °C), and higher performance of characteristics (giant ε′ 104 and low dielectric loss). These excellent performances confirmed that the prepared ceramic reveals a potential application for high-temperature Y5R and Y6R capacitors.

ADSORPTION OF HEAVY METALS USING BIO-CALCIUM CARBONATE DERIVED FROM A GOLDEN APPLE SNAIL (GAS) SHELL

In this research studied the use of calcium carbonate (CaCO3) from golden apple snail (GAS) shells for application as an absorbent material to remove heavy metals in water sources, which replaces commercial calcium carbonate (CaCO3) to reduce production costs and increase waste value. The adsorption of heavy metal contents (such as lead; Pb and Cadmium; Cd), phase formation, and physical characterization of golden apple snail shells were investigated for use as a calcium source in the production of naturally based biomaterials. The samples were calcined between 700°C and 950°C for 5 hr. TG and DTA analysis of samples demonstrated the decomposition of CaCO3 to CaO. The XRD results demonstrated that natural shell powder has a crystal phase of CaCO3 with an aragonite structure. Furthermore, the CaCO3 (calcite phase) was transformed into calcium oxide (CaO) as a component, which showed that the phase transformation depended on the calcination temperature. The adsorption experiments showed good performance at about 99.6%, 99.7%, and 97% removal efficiency in a shorter time for calcined GAS at 700, 800, and 900°C, respectively. This study suggests that the golden apple snail shell could be an effective biomaterial for heavy removal from contaminated water.

Waste catalyst potential for co-pyrolysis of biomass and single-use plastics: model-free isoconversional kinetics and thermodynamics

AbstractThe study aims to investigate the kinetic and thermodynamic characteristics of single and binary pyrolysis of biomass (date pits: DP) and single-use-plastics (polypropylene: PP, and polystyrene: PS), and the effect of adding natural catalysts—seashell (SS) and cuttlebone (CB) for ternary co-pyrolysis of the feeds. The activation energy (Ea) was calculated using different model-free kinetic methods, including Kissinger–Akahira–Sunose (KAS), Ozawa–Flynn–Wall (FWO), and Starink, utilizing information from the degradation at three heating rates from room temperature to 1173 K. The results showed that all three methods produced relatively similar Ea values with a high coefficient of correlation (R2), indicating a good fit for the data. The Ea values for single feeds of DP, PP, and PS using the FWO method were found to be in the range of 196–223 kJ/mol, while for binary feeds—DPPP and DPPPS—the values were found to be lower than for the individual plastics. The high Ea values of the binary plastic mixture are also reduced by ~ 40 kJ/mol in the ternary mixture due to biomass co-pyrolysis. Additionally, the study revealed that the addition of SS and CB catalysts positively affected the ternary co-pyrolysis by reducing activation energy by 28.5 and 5.8%, respectively, due to the catalytic activity of 20 wt% of CaCO3 decomposition from the seashell and cuttlebone added in situ to the feeds. The research contribution of this study lies in its comprehensive investigation of the kinetic and thermodynamic characteristics of biomass and plastic pyrolysis, including single and binary systems, as well as the introduction of natural catalysts for ternary co-pyrolysis. The findings highlight the effectiveness of the studied catalysts in reducing activation energy and provide valuable insights for the development of efficient biomass and plastic waste conversion processes.

Study of the illite-kaolinite-CaCO3 mixtures during firing

The raw materials used in traditional ceramics include highly plastic clay minerals such as illite or kaolinite. Non-plastic materials are usually added to the mixtures, which affect their workability and sintering process. The formation of a new crystalline phase (e.g. anorthite) is often observed in mixtures that contain a large amount of CaO. The improvement of final properties of ceramic materials is attributed to the formation of anorthite. The aim of this paper is to study the firing of anorthite ceramics in the system illite-kaolinite-CaCO3. Four sets of samples with different illite:kaolinite ratio (8:2, 6:4, 4:6, 2:8), and with a constant addition of CaCO3 are produced. The samples were subjected to the thermal and structural analyses. A significant mass loss is observed for all studied samples during the process of dehydroxylation and decomposition of CaCO3. An exothermic peak around 950 °C, which is connected with the formation of anorthite, is observed during differential thermal analysis. Above this temperature, no significant length changes are recorded. The presence of anorthite is confirmed by XRD analysis. The most formation of anorthite is observed in the illite-kaolinite sample with ratio 8:2.

Calcium wastes as an additive for a low calcium fly ash geopolymer

A geopolymer is a low-carbon cement based on the utilization of waste ash in alkali-activated conditions. Coal fly ash is widely used as a source material for geopolymer synthesis since it contains a sufficient amount of reactive alumina and silica for geopolymerization. Geopolymer products are known to have beneficial fire resistance and mechanical properties. Class F or low-calcium fly ash (LCFA) is generally used as a primary aluminosilicate source; however, heat curing is required to complete the reaction and hardening process and achieve a strong composite. Furthermore, calcium additives are often required to improve the strength of LCFA geopolymers. This paper presents the potential of reusing calcium waste for this purpose. Three calcium wastes, namely calcium carbide residue (CCR), limestone waste, and waste cement (WC) slurry in powder form were used as additives and compared with the use of ordinary Portland cement (OPC). LCFA was replaced with the calcium additives at 20%. However, 20% CCR resulted in flash setting, hence 5% CCR was used instead. A durability test using 3% HCl solution was also performed. The results showed that the reactivity of calcium additives played an important role in strength development. In the calcium–aluminosilicate–alkali system, calcium silicate hydrate (CSH) and calcium aluminosilicate hydrate (CASH) were formed. The maximum strength of 21.9 MPa was obtained from the OPC/LCFA geopolymer, and 3% HCl solution had a deleterious effect on the strength. OPC and CCR were favorable reactive sources of calcium compounds to blend with LCFA. From the thermogravimetric results, lower thermal weight changes with higher strength gains were achieved. Low CaCO3 decomposition at 750 °C according to the TGA curves indicated the more formation of thermally stable CSH and high compressive strength of Ca/LCFA geopolymers.

Calcium carbonate-actuated ion homeostasis perturbator for oxidative damage-augmented Ca2+/Mg2+ interference therapy

Ion homeostasis distortion through exogenous overload or underload of intracellular ion species has become an arresting therapeutic approach against malignant tumor. Nevertheless, treatment outcomes of such ion interference are always compromised by the intrinsic ion homeostasis maintenance systems in cancer cells. Herein, an ion homeostasis perturbator (CTC) is facilely designed by co-encapsulation of carvacrol (CAR) and meso-tetra-(4-carboxyphenyl)porphine (TCPP) into pH-sensitive nano-CaCO3, aiming to disrupt the self-defense mechanism during the process of ion imbalance. Upon the endocytosis of CTC into tumor cells, lysosomal acidity can render the decomposition of CaCO3, resulting in the instant Ca2+ overload and CO2 generation in cytoplasm. Simultaneously, CaCO3 disintegration triggers the release of CAR and TCPP, which are devoted to TRPM7 inhibition and sonosensitization, respectively. The malfunction of TRPM7 can impede the influx of Mg2+ and allow unrestricted influx of Ca2+ based on the antagonism relationship between Mg2+ and Ca2+, leading to an aggravated Ca2+/Mg2+ dyshomeostasis through ion channel deactivation. In another aspect, US-triggered cavitation can be significantly enhanced by the presence of inert CO2 microbubbles, further amplifying the generation of reactive oxygen species. Such oxidative damage-augmented Ca2+/Mg2+ interference therapy effectively impairs the mitochondrial function of tumor, which may provide useful insights in cancer therapy.

Analysis of integrated CO2 capture and utilization via calcium-looping in-situ dry reforming of methane and Fischer-Tropsch for synthetic fuels production

Calcium-looping is an attractive approach for removing CO2 in flue gas from the coal-fired power plant to form CaCO3. The integration of CO2 capture via calcium-looping and in-situ dry reforming of methane with CaCO3 allows the simultaneous CaCO3 decomposition to regenerate CaO and syngas production. The produced syngas is expected for further utilization, e.g. Fischer-Tropsch synthesis to produce valuable fuels. In this work, an integrated process of calcium-looping in-situ dry reforming of methane and Fischer-Tropsch was developed using Aspen Plus. Moreover, two other processes were also simulated as the comparison, consisting of the serial process of calcium-looping CO2 capture, ex-situ dry reforming of methane with CO2 and Fischer-Tropsch and the standalone process of calcium-looping CO2 capture. The results indicate that the reduction in the demand for CaO sorbent and the enhancement in Fischer-Tropsch products yield and carbon conversion efficiency are achieved by integrating in-situ dry reforming of methane with CaCO3. Additionally, integrating CO2 capture and in-situ dry reforming of methane with CaCO3 in the case of the integrated process is efficient for enhancing the system efficiency and energy availability. Compared with the serial process, the integrated process shows a drop in the heat energy requirement of 28.08% and possesses the energy conversion efficiency of 43.74% and exergy efficiency of 41.81%. This work exhibits the prospect of the integrated process of calcium-looping in-situ dry reforming of methane and Fischer-Tropsch in the field of CO2 capture and utilization for Fischer-Tropsch fuels production.

Characterization and mechanism of red-mud-catalyzed steam gasification of corn stover

Catalytic biomass gasification has received extensive attention from scholars worldwide. This study proposes steam gasification of corn stover using red mud (RM), an industrial solid waste, as a catalyst to produce high-quality reducing gas. Experiments were conducted at different reaction temperatures and gasification times. Characterization of RM and its three main components, Fe2O3, CaCO3, and Al2O3, in the catalytic steam gasification process of corn stover, was performed and its catalytic mechanism was explored by characterizing magnetic separation products. Results show that an increase in reaction temperature significantly promotes the production of CO, CO2, and H2. The promotion of steam to H2 production is caused by the gas-phase reaction and gasification of fixed carbon (FC). Fe2O3 promotes gas-phase reactions, such as the water–gas shift reaction, and effectively catalyzes the steam gasification of FC as an intermediate reactant. The addition of Al2O3 is beneficial for the production of CH4 and H2. The CO2 produced by the decomposition of CaCO3 inhibits the water–gas shift and methane-steam reforming reactions, thus reducing H2 output. The addition of RM is beneficial for the production of H2 and CO2 and inhibits the production of CO. Compared with pure Fe2O3, the superior pore structure and unique solid solution structure of RM provide Fe2O3 with more active surface lattice oxygen, higher redox performance, larger gas–solid contact area, superior ability to prevent carbon deposition, and better catalytic ability.

Simulation on coal combustion and calcium carbonate decomposition in a 5500 t/d full scale cement calciner

With the continuous growth of global cement production, the increasing coal consumption in the cement industry has been drawing great attention, thus adopting advanced technologies to reduce energy consumption has become an important issue. To address this problem, this study carried out 3D Eulerian-Lagrangian simulations of the coupling process of pulverized coal combustion and CaCO3 decomposition in a 5500 t/d full-scale cement calciner. On the basis of the multiphase particle-in-cell (MP-PIC) approach, reaction models including devolatilization, combustion of char and volatiles, and CaCO3 decomposition are incorporated into the scheme. Detailed combustion characteristics including temperature distribution, carbon exhaust rate, and gas emission characteristics, as well as decomposition characteristics are comprehensively analyzed. Besides, effects of different operating performances including O2 content in bottom flue gas on carbon exhaust rate, CaCO3 decomposition rate, and NOx emission are also investigated. Results show that under the typical working condition with O2 concentration in the flue gas of 1.7 %, the CaCO3 decomposition rate can reach around 96.42 %, the carbon conversion rate is up to 98.65 %, and the NOx can be controlled at around 105 ppm. The increase of O2 content promotes higher carbon conversion rates with excessive O2 leading to higher NOx emission. Appropriately increasing the proportion of raw material flow rate in upper tubes can facilitate a more complete CaCO3 decomposition.

Computational Assessment of a Novel Solar Calciner

Abstract A comprehensive computational study for the assessment of a horizontal solar calciner is presented. The heat and mass transfer models that have been developed give valuable insight and enlighten the fundamental principles that rule the solar-aided CaCO3 decomposition. The obtained computational data are appropriately interpreted and serve as guidelines in order to establish the operational framework of the solar reactor. Additionally, this set of predictive models identifies the optimum values of the key parameters that boost the performance of the process. The models have been validated comparing the computational results with the experimental data and the calciner performance is evaluated, reaching 35.2% efficiency.

In-depth insight into the effects of intrinsic calcium compounds on the pyrolysis of hazardous petrochemical sludge

To understand the potential effects of intrinsic calcium compounds on sludge pyrolysis, the pyrolysis behavior of petrochemical sludge (PS), calcium carbonate blend PS (CaPS), and decalcified PS (DePS) were investigated using thermogravimetric analysis (TGA) and in-situ Fourier-transform infrared spectroscopy coupled with pyrolysis-gas chromatography and mass spectrometry (Py–GC/MS). The TGA results indicated that decalcification increased and decreased the energy barriers of PS decomposition in ranges 200–350 °C and 350–600 °C, respectively. In contrast, copyrolysis with CaCO3 decreased the activation energy (E) of the pseudoreaction phase 2 (PH2) and altered the mechanism model. Meanwhile, during copyrolysis, char deposition and interaction hindered CaCO3 decomposition. The two-dimensional correlation spectroscopy results, on the other hand, showed that the reaction priority of O-containing groups and CH– vibration of methyl groups were affected by both decalcification and CaCO3 copyrolysis. The Py–GC/MS results indicated that the three sludges mainly released hydrocarbons, N-containing organics, alcohols, aldehydes, and acids. During pyrolysis, CaCO3 also played a neutralization role, which reduced the release of pyrolytic acidic products. In addition, the increase of the pyrolysis temperature increased the hydrocarbon content. This research will guide the industrial application of sludge pyrolysis.

Reductive calcination of calcium carbonate in hydrogen and methane: A thermodynamic analysis on different reaction routes and evaluation of carbon dioxide mitigation potential

Calcium carbonate (CaCO3) minerals represent a valuable resource, but its exploitation is based on the decarboxylation reaction at high temperatures, which inevitably release carbon dioxide (CO2) into the atmosphere. Here, a reductive calcination of CaCO3 in the hydrogen (H2) and methane (CH4) atmospheres was proposed, thermodynamic analysis and process simulation were carried out. In CH4 atmosphere, lower CaCO3 decomposition temperature and higher CO2 conversion can be achieved, while undesirable solid carbon deposition was produced as well. Optimized H2:CH4 ratio in feeding can effectively avoid carbon deposition and achieve the complete decomposition of CaCO3 at 738 °C which reaching CO2 conversion of 69.69 %. In addition, this work established the traditional route as a reference process to compare the energy efficiency and carbon footprint of the different CaCO3 calcination processes. CaCO3 calcination in H2:CH4 atmosphere with 1:1 ratio achieved an energy efficiency of 67.01 % and a GWP value of 0.954 kgCO2/kgCaCO3. With sustainable energy (bio-power, bio-H2, and bio-CH4) substitution, even lower GWP value of −0.640 kgCO2/kgCaCO3 can be achieved. This work performed that direct reduction of CaCO3 to syngas and CaO under H2 or CH4 atmosphere, which not only reduces the reaction temperature but also alleviates the CO2 emission, which offers a promising option for carbon emission reduction in the carbonate industry.

Unconfined compressive strength of MICP and EICP treated sands subjected to cycles of wetting-drying, freezing-thawing and elevated temperature: Experimental and EPR modelling

Microbial-induced carbonate precipitation (MICP) and enzyme-induced carbonate precipitation (EICP) are two bio-cementation techniques, which are relatively new methods of ground improvement. While both techniques share some similarities, they can exhibit different overall behaviours due to the differences in urease enzyme sources and treatment methods. This paper presented 40 unconfined compressive strength (UCS) tests of MICP and EICP treated sand specimens with similar average calcium carbonate (CaCO3) content subjected to cycles of wetting-drying (WD), freezing-thawing (FT) and elevated temperature (fire resistance test – FR and thermogravimetric analysis – TG). The average CaCO3 content after a certain number of WD or FT cycles (ACn) and their corresponding UCS (qn) reduced while the mass loss increased. The EICP treated sand specimens appeared to exhibit a lower resistance to WD and FT cycles than MICP treated specimens possibly due to the presence of unbonded or loosely bonded CaCO3 within the soil matrix, which was subsequently removed during the wetting (during WD) or thawing (during FT) process. FR test and TG analysis showed a significant loss of mass and reduction in CaCO3 content with increased temperatures, possibly due to the thermal decomposition of CaCO3. A complete deterioration of the MICP and EICP treated sand specimens was observed for temperatures above 600 °C. The observed behaviours are complex and theoretical understanding is far behind to develop a constitutive model to predict qn. Therefore, a multi-objective evolutionary genetic algorithm (GA) that deals with pseudo-polynomial structures, known as evolutionary polynomial regression (EPR), was used to seek three choices from millions of polynomial models. The best EPR model produced an excellent prediction of qn with a minimum sum of squares error (SSE) of 2.392, mean squared error (MSE) of 0.075, root mean square error (RMSE) of 0.273 and a maximum coefficient of determination of 0.939.

Effect of early densification on foaming process of glass–calcium carbonate mixture

The understanding of relationship between densification and foaming for preparation of foam glasses is still lacking. In this study, 128 powder compacts of glass-CaCO3 mixture were foamed isothermally for different time by varying glass particle size, foaming temperature and initial density of green compacts. The results showed that densification tends to take place in the early stage by viscous flow sintering prior to predominant foaming expansion. Therefore, there exists a critical time at which the maximum apparent density is reached, and it is correlated with both the densification rate and kinetics of CaCO3 decomposition. Such a densification has a minor effect on the minimum apparent density, however, it significantly impacts the evolution of pore structure including pore size and homogeneity, depending on glass particle size. Coarse-particle glass and high load applied on the green compacts, leading to higher green density, is favorable for slow development of pore structure with time. In this case, the foam glasses were endowed with small size of pores and homogeneity. This study provides an insight into how to obtain low apparent density and the optimum microstructure by the interplay between densification and foaming.

Usnea Acid-Incorporated Ca2+ /Mn2+ Ions Reservoirs for Elevated Ion-Interference Therapy through Synergetic Biocatalysis and Osmolarity Imbalance.

Ion-interference therapy (IIT) utilizes ions to disturb intracellular biological processes and has been received increasing attention in tumor treatments recently. However, the low therapeutic efficiency still hinders its further biological applications. Herein, via a simple and one-pot gas diffusion process, polyethylene glycol (PEG)-modified Mn2+ ions and usnic acid (UA)-incorporated CaCO3 nanomaterials (PEG CaMnUA) as Ca2+ /Mn2+ ions reservoirs are prepared for magnetic resonance imaging (MRI)-guided UA-elevated IIT. Among PEG CaMnUA, UA not only increases cytoplasmic Ca2+ ions to amplify Ca2+ overload caused by CaCO3 decomposition, but also enhances Mn2+ ions-participated Fenton-like biocatalysis by intracellular H2 O2 generation and glutathione consumption. Then increasing the intracellular oxidative stress and decreasing the triphosadenine supply induce apoptosis together, resulting in UA-boosted IIT. The simple and efficient design of the dual ions reservoirs will contribute to improve the antitumor activity of IIT and further development of calcium-based nanomaterials in the future.

Insight into the promoting effect of purified terephthalic acid sludge ash on pyrolysis of phoenix tree’s leaves

To improve pyrolysis syngas of Phoenix Tree’s Leaves (PTL), the synergistic effect of Purified Terephthalic Acid Sludge Ash (PTASA) was comprehensively investigated. In kinetics analysis, the thermal decomposition of PTL could be divided into three pseudoreactions while PTL + PTASA was with four pseudoreactions owing to the decomposition of CaCO3 as well as the reduction of inherent metal compounds (Co(II), Mn(III, IV), etc). Meanwhile, the reaction models for pseudoreaction 1 (P1) ∼ pseudoreaction 4 (P4) were fitted as D3, R2 and D3, and A15, respectively. The Ea (average activation energy) of PTL + PTASA during pyrolysis (200 ∼ 600 °C) was 6.2 % lower than the monopyrolysis which was mainly caused by the decrease of Ea in the decomposition of lignin. In addition, the crystal structure e.g. CaMnO3 (ABO3), Ca3Co2O6 (A3BB’O6), and CoO in PTASA could effectively promote the production of high-quality syngas from 41.34 % to 61.76 %. Moreover, the reaction pathways in pyrolysis of PTL + PTASA showed that the PTASA could promote the CC bond, CO bond, and C–H bond breaking of the macromolecules, e.g. anhydrosugars, N-containing compounds, and aldehydes, to produce the small molecules and release syngas. This study could provide a useful strategy for clean, valuable, and sustainable resource utilization of waste resources.