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Nitrogen oxide emissions have attracted much attention due to their impact on the atmospheric environment and human health. Combined with NO removal in the cement production process, coal gasification slag was used to prepare denitrification materials to decompose NO in cement kilns without the addition of reducing agents. Denitrification materials were synthesized by a chemical precipitation method at different pH. The denitrification mechanism was proposed in this study. The results indicated that the denitrification material prepared at a pH of 7 exhibited the best denitrification performance. The NO decomposition rate first increased and then decreased below 400°C, and then increased as the temperature increased, reaching over 97% above 700°C. In the low-temperature range, Fe(II) was assumed to be active species, and the absorbed NO on the Fe(II) site obtained an electron, which promoted the decomposition of NO. In the high-temperature range, besides the active element Fe, the residual carbon in the coal gasification slag was prone to oxidation-reduction reactions, reducing nitric oxide to nitrogen. A new waste-to-value concept is introduced in this study, which promotes green technology for sustainable development. [ABSTRACT FROM AUTHOR]

The mechanism of deactivation of MnO x /TiO 2 is studied. The MnO x /TiO 2 catalyst prepared by co-precipitation method has poor stability, the NO conversion decreased to about 50% after 100 h denitrification. Catalyst activity and physicochemical properties of the catalyst before and after SCR denitrification were compared and analyzed through BET, XRD, SEM, which indicated that dispersion of active sites and surface area of catalyst were decreased after 100 h denitrification. Catalyst activity and surface chemical compositions were investigated by XPS, H 2 -TPR, NH 3 -TPD, which shown that content of Mn3+ and chemisorbed oxygen on the surface decreases. The different active sites of catalyst and adsorption characteristics of reacting gases (NH 3 and NO) over catalyst before and after denitrification was investigated through in-situ DRIFT. It was found that NO is more easily adsorbed on the surface of catalyst than NH 3 and form nitrate. The nitrate that did not participate in the reaction gradually accumulate on the surface of the catalyst, which inhibits the adsorption of NH 3. This is the main reason for the deactivation of the catalyst. Unlabelled Image • The long-term stability of the Mn/TiO 2 catalyst was studied. • Comparing the differences in the catalytic activity and physicochemical properties of fresh and used catalyst. • Showing the atomic-scale insights into mechanism of deactivation for Mn/TiO 2 catalyst. [ABSTRACT FROM AUTHOR]

The commercial fluorocarbon surfactant (FCS) DuPont™ Zonyl 321 fluorinated cationic surfactants, was employed to modify both flat‐sheet and hollow‐fiber poly(tetrafluoroethylene) (PTFE) porous membranes. The variation of morphology, wettability, and hydrophilicity durability to acid and alkali as well as the filtration performance of both membranes were investigated. Such superhydrophilic membranes showed better wetting stability and higher resistance to acid and alkali solutions. Moreover, both membranes exhibited good filtration performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Design a method based on DFT calculations to study the modification of the manganese-based catalyst. • Explain the reason why MnO 2 doped by different element show different sulfur resistance. • Unravel the catalytic property of MnO 2 doped by different element on NH 3 -SCR. Modification of manganese-based selective catalytic reduction (SCR) catalyst by five kinds of the element was studied to improve its SO 2 resistance. In this paper, density functional theory (DFT) calculation was used to analyze the effects of doped atom on electronic dispersion and crystal structure of MnO 2 (100). Our result demonstrated that the doping of Ni, Cr, and Co could increase the strength of Lewis acid sites for the manganese-based catalyst, while Se and Sn decrease that. On the other hand, the manganese-based catalyst modified by Se and Sn present better resistance to sulfur poisoning. By comparing the dissociation energy barrier of NH 3 over different element doped catalyst and analyzing the partial density of state (PDOS) for SO 2 adsorbed on the catalyst, we found that Cr could be as a potential dopant modifying the manganese catalyst, because of it could convert sulfur to Brønsted acid sites which catalyze NH 3 -SCR through followed the LH-mechanism. [ABSTRACT FROM AUTHOR]

Mn/TiO 2 catalysts has been shown excellent selective catalyst reduction (SCR) activity at low temperature. However, the exhaust gases in some plant contained alkali metal compounds after dust removal, which showed a serious poisoning effect on activity of Mn/TiO 2 catalyst. Our previous work showed that the poisoning effect of potassium on catalyst was most serious among these alkali elements. In the study, in situ diffuse reflectance infrared transform spectroscopy (DRIFT) and density function theory plus dispersion (DFT-D) calculation were used to investigate the mechanism how the potassium species have a negative impact on Mn/TiO 2 catalytic. The results indicated that there were two reasons for that alkali metal elements make the Mn/TiO 2 catalyst inactive. The first one is that the amount of NH 3 adsorption was on the Lewis acid sites, which was main active substances for the reduction of NO. The second one is that the electrons tend to occupy high energy states under effect of potassium, which resulted in decrease of oxidative capacity of catalyst. [ABSTRACT FROM AUTHOR]

[Display omitted] The reaction mechanism of selective catalytic reduction of NO with ammonia (SCR) on MnO x /TiO 2 catalysts was investigated through experiments and density functional theory (DFT) calculation. Firstly, the catalytic performance of catalyst with different molar ratios of MnO x /TiO 2 was investigated and then was analyzed by NH 3 temperature programmed desorption (NH 3 -TPD). The crystalline structure and the valence state of the MnO x /TiO 2 catalyst were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). According to the results, the model of MnO x /TiO 2 was established. Secondly, the different active sites of catalyst surface and adsorption characteristics of reacting gases during the SCR reaction based on in-situ DRIFT was investigated. Finally, the energy of different elemental reaction and isomerization of intermediate was calculated by MS Dmol3. It was found that the main active substance of catalyst was Mn4+ species which distributed dispersedly on the catalyst surface. The introduction of MnO x dopant can promote the adsorption of gas and reduce the formation energy of oxygen vacancy. The complete catalytic cycle goes in three steps: (a) Lewis acid site reaction follows Eley-Rideal mechanism; (b) Brønsted acid site reaction follows Langmuir-Hinshelwood mechanism; (c) Regeneration of catalyst. [ABSTRACT FROM AUTHOR]

It is possible to remove volatile organic compounds containing chlorine (CVOCs, such as chlorobenzene) in a single device designed for selective catalytic reduction of NOX with NH3 for the industries containing CVOCs and NOX. Breaking the efficiency-selectivity trade-off in chlorobenzene oxidation remains a major challenge due to the conjugation of halogen atoms with the benzene ring and the reducing nature of NH3. A stepwise synthesis strategy is demontrated to disperse dual Ru/Cu Lewis acid sites outside and inside the zeolite channel. Under the confinement of zeolite, the Ru4+ Lewis acid site on the external surface of the zeolite promotes chlorobenzene oxidation by weakening the p-n conjugate structure of Cl and benzene ring, while the Cu2+ Lewis acid site within the internal channel converts NOX and NH3 to N2. The mutual interference between catalytic oxidation and reduction is successfully avoided. Therefore, the low toxic CO2 and HCl selectivity experience a considerable increase from 21% to 86%, and from 51% to 94% with 91% conversion of chlorobenzene, while maintaining excellent elimination performance for NO (with N2 selectivity exceeding 90%). The incorporation of separated active sites and reaction spaces into the design may offer potentials for other energy and environmental applications. [ABSTRACT FROM AUTHOR]

Experimental data is often corrupted by measurement noise in practical engineering and there are multiple observed data under the same experimental condition. The noisy measurement data can be considered as the response of an underlying stochastic dynamical system. To explore the response properties from noisy measurement data with the partial information of the given stochastic dynamical system, a novel method named as the stochastic generalized cell mapping with deep learning (SGCM-DL) is proposed based on the idea of the image processing. Noisy measurement data is reconstructed into a matrix to be expressed by the image, which is used as the training data of the neural network. The obtained neural network agent model is combined to reveal properties of the underlying stochastic dynamical system and employed to predict stochastic responses with given initial values by the way of the image generation. The technique of the image super-resolution (SR) is introduced to generate the image with higher resolution from the output image of the neural network. Based on the image with higher resolution, one-step transition probability matrix with the larger dimension is obtained for stochastic dynamical systems. Then probability density functions (PDFs) of transient and stationary responses can be obtained by the proposed method in this paper. Several examples are presented, and the good effectiveness and time-saving are observed. • Explore the response properties from noisy measurement data with partial information for given stochastic dynamical systems. • A novel method is proposed based on the idea of the image processing, named as SGCM-DL method. • The training data of the neural network is reconstructed into a matrix to be expressed by the image. • Combining the technique of image super-resolution, transient and stationary responses are obtained. • The numerical results show the good effectiveness of the SFCM-DL method. [ABSTRACT FROM AUTHOR]

The mechanisms of sulfur dioxide poisoning on Mn/TiO 2 and Mn-Ce/TiO 2 catalysts are studied and poisoning resistance effect of cerium is revealed. Both two kinds of catalysts were deactivated to reduce NO x removal in the presence of SO 2 , however, the sulfur resistance performance of the Ce doping catalysts was obviously improved. From the result of DRIFT and DFT, SO 2 can first adsorb on the manganese-terminal (Lewis acid sites) to form sulfates, which inhibit the adsorption of NH 3 in the SCR reaction. Deactivation of Brønsted acid sites was due to the formation of bisulfite, which can react with NH 4 + form NH 4 HSO 4 . For the Mn-Ce/TiO 2 catalysts, SO 2 preferentially adsorbed on Ce atom as sulfate species, alleviating the sulfation of the main active sites (Lewis acid sites and Broøsted acid site on MnO x ) under the effect of SO 2 . Furthermore, cerium sulfate can produce new Brønsted acid site and contribute to the low-temperature SCR processes. [ABSTRACT FROM AUTHOR]

The adsorption of NO and NH 3 gaseous molecules on Mn 3 O 4 /TiO 2 catalysts is studied based on density function theory and the corresponding experiments for low-temperature SCR of NO x by ammonia. The SCR performances of the Mn 3 O 4 /TiO 2 catalysts prepared by joint precipitation method were systematically carried out in the temperature range of 90–300 °C. The results show that nitrogen oxide can first adsorb on the manganese-terminal to form nitrates species, and then NH 3 are more inclined to adsorb on Brønsted acid sites. Bridging nitrate and bidentate nitrate can be turned into monodentate nitrates, and NH 4 + was formed when there is ammonia and water molecules because the adsorption and dissociation of the water on the surface of the catalyst is the main source of hydroxyl groups. It is indicated that L-H mechanism plays a major role in NH 3 -SCR process. [ABSTRACT FROM AUTHOR]

The poisoning of alkali metal on MnO x /TiO 2 catalysts used for selective catalytic reduction (SCR) of NO x by NH 3 was investigated. KNO 3 , KCl and K 2 SO 4 were doped on MnO x /TiO 2 catalysts by sol–gel method, respectively. The SCR activity of each catalyst was measured for the removal of NO x with NH 3 in the temperature range 90–330 °C. The experimental results showed that catalyst with KNO 3 have a stronger deactivation effect than other catalysts. The properties of the catalysts were characterized by XRD, BET, SEM, XPS, H 2 -TPR, NH 3 -TPD and in situ DRIFTS analyses. The characterized results indicated that KNO 3 , KCl and K 2 SO 4 caused the similar decrease of specific surface area and pore volume, but the quantity of acid sites for KNO 3 -MnO x /TiO 2 catalyst reduced sharply. The main reason for catalyst deactivation is attributed to two aspects: one was physical influences for the decrease of surface area and pore volume, another was chemical influences that the K + ions decomposed by KNO 3 neutralized Brønsted acid sites of catalyst and reduced their reducibility. The chemical influence played a leading role on the deactivation of catalysts. [ABSTRACT FROM AUTHOR]

To make effective use of plant leaves as an environment-friendly heat-insulating building material, our research group has tested five poplar leaf modification methods to improve compatibility between leaf fibres and cement-based materials. The work involved testing water absorption of before and after modification of leaf fibres, the setting time and hydration heat of the fibre–cement paste, and analysed the mechanisms and effect of fibre modification methods on compatibility between fibres and cement-based materials. The results show that processing of fibres with surface coating and dipping methods improved compatibility between fibres and cement-based materials to some extent and in different aspects. Overall, the following three methods gave superior performance: pure acrylic polymer emulsion spraying, sodium silicate solution spraying and water dipping. [ABSTRACT FROM AUTHOR]

• Providing references for the application of mineral polarization effect to the field of denitration catalysis. • A microcosmic mechanism for tourmaline affecting denitration catalytic material is proposed. • Under the action of electric field, the band gap of catalyst become narrower, the gas delocalization is enhanced. Development of the efficient MnO x /TiO 2 catalysts with high dispersibility and stability of denitration reaction for NH 3 -SCR is crucial to control NO x emission at low temperature. Herein, we propose mineral polarization effect modification on the surface of MnO x /TiO 2 denitration catalytic material via coprecipitation method using tourmaline as modifying agent, and evaluate its performance of NO x removal. Particularly, tourmaline-MnO x /TiO 2 catalysts presented a high denitration rate about 97% under the condition of 1000 ppm NO, 1000 ppm NH 3 and 5% O 2 at 200 °C and maintained above 91% removal efficiency within 10 h, which was mainly ascribed to the polarization effect of tourmaline. The doping of tourmaline could improve the dispersion of catalytic materials, reduce the band gap width, and promote the activation of NH 3 and the oxidation of NO. Moreover, the microscopic mechanism was studied by density functional theory (DFT) calculation from the aspects of adsorption energy, mulliken charge and density of states during the adsorption process. Overall, the results of this study will provide references for the application of mineral polarization effect to the field of denitration catalysis and promotes the further understanding of the mechanism for deNO x reaction process. [Display omitted] [ABSTRACT FROM AUTHOR]

Highlights: [•] Catalysts of Mn-Ce-M/TiO2 (M=Fe, Ni) prepared by co-precipitation method for low temperature selective catalytic reduction (SCR). [•] Using carbamide solution, ammonia and hydrogen peroxide as precipitation agents, showed good activity in low temperature and resistance performance of K+ cation (K/Mn=0.5). [•] Poisoning mechanism occurs via chemical bonding of the K+ cation to the M OH sites, the so-called Brønsted acid sites. [ABSTRACT FROM AUTHOR]

Highlights: [•] Several kinds of leaves and leaf concrete hydrated products were tested and analyzed with SEM–EDS. [•] The micro-morphology of leaf concrete is greatly different from that of ordinary concrete. [•] The heat-isolating property of test specimens with different micro-morphologies was tested. [•] With the increase in dosage of leaves, heat-insulation effect of leaf concrete is enhanced. [Copyright &y& Elsevier]

• The construction of inherent reactive XPSF surface by ultraviolet-zone. • The fabrication of covalently bonded XPSF/mortar interfaces. • The thorough investigation of the reactions between APTES and XPSF surface. The inert surface of extruded polystyrene foams (XPSF) was activated by ultraviolet-ozone (UVO) for the first time to improve the interfacial compatibility with mortar. From the structural analysis (X-ray photoelectron spectroscopic (XPS) and contact angle (CA)), it was suggested that a 10 min UVO exposure was efficient enough to introduce oxygen-contained elements (such as carboxyl groups) upon the obtained UVO-XPSF surface, leading to the increased bonding strength (BS) from 0.058 MPa of neat XPSF/mortar composites to 0.088 MPa. Then, 3-aminopropyl triethoxysilane (APTES) was selected as the promoter to further enhance the BS value of XPSF/mortar composites. The presence of the silane was confirmed by CA, Fourier transform infrared-attenuated total reflection (FTIR-ATR) and XPS. By optimizing the reaction conditions (activation and reaction time: 7 and 3 min, concentration of APTES: 2% and pH value of the silane solution: 10), a maximum BS of 0.168 MPa could be obtained. Through the mechanism analysis, it was demonstrated that APTES acted as a chemical bridge that covalently jointed XPSF by the formation of amide peptide and inorganic mortar by the condensation of silanols. [ABSTRACT FROM AUTHOR]

• KT could enhance As uptake in fronds of two plants. • KT promoted the growth of the two plants. • KT can significantly increase SOD and CAT activities in two plants. • KT contributed to As tolerance in plants under different As species stress. Cytokinins (CTKs) enhance plant tolerance to heavy metals, but the associated mechanisms are not yet fully understood. Here, we investigated the effects of kinetin (KT, a type of CTKs) on arsenic (As) speciation and antioxidative enzymes in plant fronds, by comparing Pteris cretica var. nervosa (As hyperaccumulator) and Pteris ensiformis (non-hyperaccumulator). A hydroponic test was carried out and the two plant species were treated with 2 mg L−1 arsenite [As(III)], arsenate [As(V)] or dimethylarsinate (DMA), and then 0–1.0 mg L−1 KT was exogenously applied for 14 days. The maximum As uptake of the two experimental plants was 0.5 mg L−1 KT. Fresh plant biomass was also significantly increased, except in P. cretica var. nervosa under DMA stress. The frond superoxide dismutase (SOD) and catalase (CAT) activity in the two plant species was significantly increased by 0.5 mg L−1 KT. Additionally, a significant decline in frond peroxidase (POD) activity was observed in P. ensiformis at 1.0 mg L−1 KT under As(III) stress. However, POD activity was significantly increased in P. cretica var. nervosa , at 0.1 mg L−1 KT, under As(III) or DMA stress, and at 1.0 mg L−1 KT, under As(V) stress. Therefore, KT promoted As transport and increased frond POD activity in P. cretica var. nervosa , which contributed to its As tolerance under stress from different As species. [ABSTRACT FROM AUTHOR]

In this work, a novel intumescent flame retardant (IFR) system was fabricated by the introduction of chitin as a green charring agent, ammonium polyphosphate (APP) as the acid source, and melamine (MEL) as the gas source. The obtained chitin-based IFR was then incorporated into a polylactic acid (PLA) matrix using melt compounding. The fire resistance of PLA/chitin composites was investigated via the limiting oxygen index (LOI), UL-94 vertical burning, and cone calorimeter (CONE) tests. The results demonstrated that the combination of 10%APP, 5%chitin and 5%MEL could result in a 26.0% LOI, a V-0 rating after UL and a 51.2% reduction in the peak heat release rate during the CONE test. Based on the mechanism analysis from both the morphology and the chemical structure of the char, it was suggested that chitin was a promising candidate as a charring agent for chitin reacted with APP and MEL with the formation of an intumescent layer on the surface. [ABSTRACT FROM AUTHOR]

Pb SA -Cu/PC with a three-dimensional structure was demonstrated as an efficient CO 2 reduction catalyst to formate. Pb inhibited the formation of COOH*, reduced the energy barrier of rate determining step in the formate formation process, and achieved 97% high formate selectivity. [Display omitted] • Pb SA100 -Cu/CP catalyst is developed by an economical and low-energy method. • The FE formate is 97 % with a partial current density of 27.9 mA cm−2 at − 0.9 V. • The catalyst exhibits ultra-long stability for more than 60 h. • The synergistic action of Pb SA and Cu atoms lowers the RDS for CO 2 RR to fromate. • Single-atom Pb induces Cu charge redistribution and inhibits the formation of COOH*. Exploring highly selective and stable electrocatalysts is of great significance for the electrochemical conversion of CO 2 into fuel. Herein, a three-dimensional (3D) nanostructure catalyst was developed by doping Pb single-atom (Pb SA) in-situ on carbon paper (Pb SA100 -Cu/CP) through a low-energy and economical method. The designed catalyst exhibited abundant active sites and was beneficial to CO 2 adsorption, activation, and subsequent conversion to fuel. Interestingly, Pb SA100 -Cu/CP showed a prominent Faraday efficiency (FE) of 97 % at –0.9 V versus reversible hydrogen electrode (vs. RHE) and a high partial current density of 27.9 mA·cm−2 for formate. Also, the catalyst remained significantly stable for 60 h during the durability test. The reaction mechanism was investigated by density functional theory (DFT), demonstrating that the doping Pb SA induced the electrons redistribution, promoted the formate generation, reduced the rate-determining step (RDS) energy barrier, and inhibited the hydrogen evolution reaction. The study aims to provide a new strategy for developing of single-atom catalysts with high selectivity and stability, which will help reduce environmental pressure and alleviate energy problems. [ABSTRACT FROM AUTHOR]

In order to obtain low-cost and excellent adsorption materials, this paper used calcium acetate and water glass as raw materials to synthesis hydrated calcium silicate gel by precipitation method. The performance and structure of hydrated calcium silicate gel were systematically studied by X-ray photoelectron spectroscopy, fourier transform infrared spectroscopy, specific surface area analyzer and scanning electron microscope. Studies have shown that, non-crystal hydrated calcium silicate gel (CSH) were successfully prepared, and the removal rate of lead ion using CSH reached more than 90%. The adsorption process is consistent with the pseudo-second-order kinetic model and Langmuir adsorption isotherm model, and the limit adsorption capacity reaches 263.17 mg·g−1. The acid treatment experiment proved that the adsorption capacity of lead ion using CSH was satisfactory, and the adsorption rate remained at >60% after 5 cycles. The research may provide a low-cost, high-efficiency and high stability adsorbent. [ABSTRACT FROM AUTHOR]

Selective catalytic reduction (SCR) technology is the most widely used flue gas denitration technology at present. The stability of a catalyst is the main factor limiting the development of this technology. In this study, an environmentally friendly and highly efficient NH3-SCR catalyst was prepared by coprecipitation method from acidolysis residue of industrial waste and tourmaline. We found that the addition of tourmaline has an important impact on the denitration activity of the catalytic material. The NOx conversion exceeded 97% at 200 °C with the dosage of 10% tourmaline, which is about 7% higher than that without doping. The improvement of catalytic performance was mostly attributed to the permanent electrodes of tourmaline, which effectively promotes the dispersion of MnOx/TiO2 catalytic materials, increases the number of acidic sites and changes the valence distribution of manganese ions in products, which speeds up the diffusion of protons and ions, resulting in the acceleration of redox reaction. These as-developed tourmaline-modified MnOx/TiO2 materials have been demonstrated to be promising as a new type of highly efficient low-temperature NH3-SCR catalyst. [ABSTRACT FROM AUTHOR]

Nitrogen oxide (NOx) emissions have attracted much attention for increasing concern on the quality of the atmospheric environment. In view of NO decomposition in the cement production process, the preparation of Cu-Al/SiO2 porous material and its effect on NO decomposition were studied, and the denitrification mechanism was proposed in this paper. The NO decomposition performance of the Cu-Al/SiO2 porous material was tested via the experimental setup and infrared spectrometer and micro gas chromatography (GC). The result shows that the Cu-Al/SiO2 porous material with the template of cetyltrimethylammonium bromide (CTAB) had a better NO decomposition rate than materials with other templates when the temperature was above 500 °C, and NO decomposition rate could approach 100% at high temperatures above 750 °C. Structure analysis indicates that the prepared Cu-Al/SiO2 material structure was a mesoporous structure. The X-Ray Diffraction (XRD) and Ultraviolet–visible spectrophotometry (UV–Vis) results of the denitrification product show that the Cu-Al/SiO2 material mainly decomposed to Cu2O and Si2O, and the CuO decomposed to Cu2O and O2 at high temperature. The Cu(I)O was considered as the active phase. The redox process between Cu(II)O and Cu(I)O was thought to be the denitrification mechanism of the Cu-Al/SiO2 porous material. [ABSTRACT FROM AUTHOR]

Tertiary alkanolamines play an essential role in the hydration of cement-based materials as one of the main components of cement grinding aids and concrete admixtures. Although the field has been well-studied, the significant effects of slight variations in alkanolamine type and dosage make it imperative for researchers to fully understand alkanolamines before using them. Therefore, it is necessary to understand in detail the mechanism of different alkanolamines affecting the hydration of cement-based materials and their effects on setting and hardening. Based on the synthesis and chemical characteristics of alkanolamines, the complexation between alkanolamine and metal ions is discussed in this paper. The influence of alkanolamines on hydration of cement-based materials and the role of complexation in hydration are studied. Various properties of cement-based materials in the presence of alkanolamines are rigorously reviewed. The synergistic effects of alkanolamine and other admixtures are also considered in this review. The research findings prove that the complexation of alkanolamines plays an essential role in hydration and further interferes the microstructure and properties of the cement-based materials. Variations in the molecular structure and dosage of alkanolamines can lead to significant differences in hydration. The modification of alkanolamines at the molecular level and their use in combination with other admixtures are the future research directions. The working mechanism of alkanolamines in the hydration process of cement-based materials still needs to be further explored. • Complexation of alkanolamines significantly affects cement hydration. • Different alkanolamines have different effects on mineral phase hydration. • Alkanolamines significantly affect the morphology of C-S-H gels and Ca(OH) 2. • The right dosage of alkanolamine could improve compressive strength. • TEA has a significant effect on setting time. [ABSTRACT FROM AUTHOR]

Steel slag (SS) as a supplementary cementitious material has low cementitious activity. Diethanol-isopropanolamine (DEIPA) is an organic admixture that can enhance the cementitious activity of cementitious materials. This work aimed to investigate the hydration characteristics of SS under the complexing of DEIPA. The hydration process of SS, the complexation of DEIPA with metal ions, and the dissolution process of C 3 A and C 3 S in the presence of DEIPA were systematically investigated. The results showed that DEIPA enhanced the hydration of aluminate (C 3 A and C 12 A 7), ferrate (C 2 F) and silicate phases (C 3 S and C 2 S), which formed a large amount of monocarboaluminate, paraalumohydrocalcite and C–S–H gels. In the early stages of hydration, the hydration products were mainly C–S–H gels, monocarboaluminate and paraalumohydrocalcite, and in the later stages of hydration, the hydration products were mainly C–S–H gels, paraalumohydrocalcite. The monocarboaluminate may be transformed to paraalumohydrocalcite at a later stage. This hydration-promoting effect was related to the complexation of DEIPA. DEIPA facilitated the dissolution of mineral phases and the precipitation of complexed metal ions by complexing with metal ions. The stronger complexation of Al3+ by DEIPA made it more solubilizing for C 3 A. As a result, more aluminum-containing hydration products were formed. The weaker complexation of Ca2+ by DEIPA made it a weaker solubilizing for C 3 S, which also led to a weaker promotion of silicate hydration by DEIPA. The solubilization of DEIPA to minerals enhanced the cementitious activity of SS, which ultimately led to the increase in the compressive strength of the hardened SS paste at each age. [ABSTRACT FROM AUTHOR]

Ferroaluminate cement is widely used in marine engineering applications owing to the remarkable durability and strength of its main hydrate, Al(Fe)–ettringite. The structure and performance of Al(Fe)–ettringite still require extensive exploration. An Al(Fe)–ettringite molecular model containing different Fe contents (0%, 25%, 50%, and 75%) was developed via Materials Studio. Radial distribution functions, time-correlated functions, and mean square displacement were used to analyze the structure of Al(Fe)–ettringite, after which Al(Fe)– ettringite was prepared using a coprecipitation method. The hydration of Al(Fe)–ye'elimite, the nanoindentation testing, and compressive strength of four ettringite types were assessed to facilitate a comparison with the simulation results. Increasing the Fe content resulted in increased lattice size and density. Fe atoms mainly reacted with Ohs atoms to form Fe–Ohs bonds, resulting in an increased Fe–Ohs bond length, with the Fe atom density resulting in volume expansion and increased density in Al(Fe)–ettringite. At 25% Fe content, the number of Hw–Ow hydrogen bonds in Al(Fe)–ettringite was 1166.14, the MSD value was 1.53 Å2, and the water molecules diffused the fastest. The improved macromechanical properties obtained by adding Fe atoms demonstrate that Fe atom substitution can enhance the ettringite structure. The experimental results validated the simulation results. [ABSTRACT FROM AUTHOR]

In this paper, the strength development of a pure steel slag (SS) system with various concentrations of N,N,N′,N′-Tetrakis-(2-hydroxyethyl) ethylenediamine (THEED) was investigated. The hydration kinetics, pore structure and microstructure of SS pastes with and without THEED were characterized to underscore the working mechanism of THEED. Results show that THEED additions significantly increase the 3, 7 and 28 days compressive strength of hardened SS pastes. The enhancement effect increases with the dosage of THEED. At a concentration of 2000 ppm, THEED increased the compressive strength by 733%, 665%, and 545% at 3, 7 and 28 days, respectively. It is confirmed that THEED additions improve the hydration degree of SS by accelerating hydration of the aluminum phase (C3A, PDF-38-1429; C12A7, PDF-48-1882) and C2F,(PDF 38-0408) to generate Mc (PDF-41-0219) and Pa (PDF-30-0222) in the presence of CaCO3. Also, the hydration degree of silicates is increased by THEED. In this way, THEED additions refine the pore structure of hardened SS paste by increasing the pore volume with a diameter below 300 nm to achieve enhancement. The chelating effect of THEED results in promoting dissolution of SS, which provides the driving force for accelerating SS hydration. [ABSTRACT FROM AUTHOR]

NOx emission from the cement industry have received much attention. In order to reduce the NOx emission in cement kilns, nickel slag was used to prepare the non-ammonia denitrification material, and a denitrification mechanism was proposed in this study. The results showed that the denitrification material prepared at pH 7 exhibited the best denitrification performance. At low temperature, the highest denitrification performance was achieved between 200 and 300 °C with a NO decomposition rate of approximately 40%. Then, the NO decomposition rate increased as the temperature increased, reaching over 95% above 700 °C. The physicochemical characteristics showed that the material had the highest specific surface area and the highest relative Fe content, which benefited the denitrification performance. The divalent iron of the denitrification material was considered the active site for the reaction, and trivalent iron was not conducive to denitrification performance at a low temperature range. After the denitrification reaction, the Fe3+/Fe2+ increased from 0.89 to 1.31. The proposed denitrification mechanism was the redox process between divalent iron and trivalent iron. This study not only recycles industrial waste to reduce solid waste pollution but also efficiently removes nitrogen oxides from cement kilns without ammonia. [ABSTRACT FROM AUTHOR]

The impact on hydration of four kinds of alkanolamines (triethanolamine (TEA), triisopropanolamine (TIPA), diethanol-isopropanolamine (DEIPA) and methyldiethanolamine (MDEA)) in a steel slag cementitious system was reviewed. Isothermal calorimetry studies provided information on the hydration heat release rate and the cumulative energy released by blend cement systems. Mortar strength, quantitative X-ray diffractometry, mercury intrusion pore size distribution analysis, scanning electron microscopy and thermogravimetric analysis were used to analyze the mechanism of strength enhancement and micro-structure of hydrates that were impacted by alkanolamines. Alkanolamines prolonged the hydrated induction period in the steel slag–cement system, and enhanced the second exothermic peak of hydration at dosages of 0.01%, 0.03% and 0.05%. The second hydration rate was decreased by TEA, DEIPA and MDEA, and increased by TIPA at alkanolamine dosages of 0.1% and 0.2%. The compressive strength and non-evaporable water content were enhanced by the four types of alkanolamines (dosage of 0.03%) at 3 d, 7 d and 28 d, which allowed TEA and DEIPA to contribute to strength development and the hydration reaction over TIPA and MDEA. The CH content, porosity and pore size were decreased by alkanolamines at different ages. Alkanolamines promoted the formation of ettringite and an alumina–ferric oxide–monosulfate phase, and the C–S–H morphology was also changed by different kinds of alkanolamines. [ABSTRACT FROM AUTHOR]

The combined utilization of mineral accelerators and nano-seeding materials is a novel method to promote the early strength of cement-based materials. In this paper, the effects of nano-C-S-H seed (NCS) on the early compressive strength of the Portland cement (PC)– calcium sulfoaluminate cement (CSA) binder were investigated. The results showed that NCS and CSA synergistically contributed to the early strength of PC. In detail, a 326.3% increase in the 10 h compressive strength of PC paste was obtained through the addition of NCS (2 wt%) and CSA (5%) in common. This was higher than the sum of the increases observed with the single additions of CSA (157.9%) or NCS (87.6%), with the same above dosage, in PC. Meanwhile, the early strength enhancement effects of NCS and CSA, when used together in PC, lasted longer than the effects of either used alone. Moreover, the synergetic effect mechanism was analyzed by isothermal calorimeter, QXRD, TGA, MIP, and SEM techniques. The calorimetry, XRD, and TGA results demonstrated that the synergistic mechanism was associated with the synergistic promotion effects of CSA and NCS on the hydrates. The fast hydration of CSA produced large amounts of ettringite and also consumed partial free water to promote the performance of the seeding effect of NCS which, simultaneously, further accelerated the precipitation of C-S-H gel and CH. The high alkie environment was also beneficial for the continuous generation of ettringite. In addition, the results of MIP and SEM measurements showed that the micro-filling effect of NCS significantly optimized the pore structure of a PC-CSA blend-hardened paste. Thus, the synergistic strength enhancement effects of CSA and NCS on PC were attributed to the matching of the promotion of hydration generation and the optimization of pore structures in hardening cement paste. The results of this article provide a new approach to achieving the rapid development of the early strength of cementitious materials, with potential applications in precast concrete and low-temperature construction. [ABSTRACT FROM AUTHOR]

Concrete cracking has a negative impact on the durability of the structure. Pre-implanting microcapsules containing healing agents into the concrete are expected to induce the cracks to self-heal. However, the self-healing effect can potentially be influenced by several environmental conditions, thus limiting its applications. To address these challenges, we developed a new type of water-absorbing microcapsules, using calcium alginate hydrogel as the wall material and an adhesive epoxy polymer as the core material, to improve the self-healing adaptability in complex and changing environments. We explored the healing properties and mechanism of cementitious materials containing microcapsules under various environmental conditions. The experimental results showed that the water-absorbent microcapsules exhibit multiple self-healing effects under different external conditions: (1) in an anhydrous environment, fissures prompted the activation of microcapsules, and the epoxy polymer flowed out to seal the cracks. (2) When exposed to water, the microcapsules inflated to form a seal around the fissures. (3) The microcapsules facilitated the autogenous healing of cracks in the cementitious material when wet and dry conditions were alternated. The three self-healing mechanisms worked synergistically and contributed to the effective restoration of the impermeability and strength of concrete under different environments. Particularly, the recovery of compressive strength and impermeability exceeded 100% when the microcapsule content was 4% and the pre-pressure was 40% of fmax. [ABSTRACT FROM AUTHOR]

Ca(OH)2, a widely available and low-cost calcium-based desulfurizer, needs further improvement in calcium utilization in flue gas desulfurization. In this experiment, Ca(OH)2 crystals with different morphologies were prepared by doping impurity ions including SO42− and SiO32− by precipitation method, which played directing role in the process of crystal growth. The prepared Ca(OH)2 crystals were applied to cement kiln flue gas desulfurization environment to investigate the effect of crystal morphology on flue gas desulfurization. The observed results illustrated that Ca(OH)2 prepared by SO42− as impurity ion in hexagonal plate shape presents the best desulfurization performance with desulfurization efficiency up to 93%. The structural characterization of Ca(OH)2 crystals by XRD and SEM, and the investigation of the reasons for desulfurization by BET, EDS, and XPS showed that the hexagonal plate-shaped Ca(OH)2 crystals increased the specific surface area and had the highest elemental sulfur content of 5.04% on the (100) crystal plane, and the high surface energy on the (100) plane led to the high reactivity. This confirms the guiding significance of hexagonal plate-like morphology for improving the desulfurization performance of Ca(OH)2. [ABSTRACT FROM AUTHOR]

Reducing or eliminating cracks caused by shrinkage of cementitious materials remains a daunting challenge for construction engineers. Drying shrinkage and autogenous shrinkage are the main shrinkage types in the service process of cement-based materials, which have a great impact on engineering applications. If cracks in concrete generate by drying or autogenous shrinkage, the mechanical properties, water resistance and durability of concrete will be also affected. It is an effective method to use chemical admixtures to inhibit the shrinkage of cement-based materials. Polycarboxylate plasticizer (PCE) is an important chemical admixture in cement-based materials and is widely used in practical engineering. It can bring great value by reducing the shrinkage effect through molecular design. Through our innovative design, a series of shrinkage-reducing polycarboxylate superplasticizers (SRPs) were synthesized, their molecular structures were confirmed by Fourier transform infrared spectroscopy (FTIR) and their molecular properties were determined by gel permeation chromatography (GPC). Furthermore, the shrinkage performances at different ages of the mortars containing the synthesized SRPs with different structures were systematically evaluated. The results showed that compared with the blank sample, the dry shrinkage rate and free shrinkage rate of the mortars containing SRP decreased by over 20% and 15%, respectively. Additionally, the shrinkage rates of the mortars containing SRP were significantly lower than that of the mortar containing conventional PCE, and moreover, the water-reducing performance was improved compared to conventional PCE. Based on the experimental results of surface tension and evaporation rate of different SRP solutions, the mechanism of the shrinkage-reducing effect was probed, as expected to provide guidance for the design and development of new shrinkage-reducing admixtures. [ABSTRACT FROM AUTHOR]

Polycarboxylate ether (PCE) superplasticizers are widely used in concrete, but in some cases, PCE aggravates the occurrence of cracks. This study evaluates the shrinkage reduction and plasticizing properties of a newly synthesized shrink-reducing polycarboxylate polymer (KH-SRPC) modified with ester and silane groups. When the KH-SRPC was implemented at a dosage of 0.3% by weight of cement, the adsorption capacity on the surface of the cement particles and the spreading diameter of the cement improved with respect to traditional PCE. Furthermore, the autogenous shrinkage and drying shrinkage of the mortar containing KH-SRPC were also investigated. When the KH-SRPC content was 0.2% of the weight of the cementitious material, the autogenous shrinkage of the KH-SRPC mortars at 3 and 7 days was reduced by 72.6% and 43.5%, respectively. The drying shrinkage of KH-SRPC mortars decreased by 38.3% at 3 days, 39.0% at 7 days, 39.1% at 14 days, and 35.7% at 28 days. It was found that KH-SRPC changed the pore structure of the solidified mortar, reduced the surface tension of the pore solution, and slowed down the rate of hydration, thereby reducing the total shrinkage of the mortar system. [ABSTRACT FROM AUTHOR]

The issue of slow early setting and strength development is a common problem faced by natural hydraulic lime (NHL) in both historic building restoration projects and modern construction. This study aims to reveal the phase composition and microstructure of natural hydraulic lime-based materials modified by metakaolin and its effect by natural carbonation. The results demonstrate that metakaolin could promote the setting times of NHL and generally exhibit a significant enhancement effect on the mechanical strength. Additionally, the drying shrinkage of NHL mortar can be effectively reduced by adding 10% metakaolin. In terms of hydration products, C4AĈH11 and C-S-H are identified as primary products during the early stages for M-NHL mortars, along with other hydration products such as C-A-(S)-H being formed later on. At longer ages, the carbonation reactions occur primarily with C-S-H and C-A-(S)-H phases, while decomposition or transformation into other phases is more likely for C4AĈH11. Interestingly, when M-NHL mortars with 10% metakaolin, it not only promotes early hydration but also enhances long-term carbonation processes. The carbon dioxide uptake effect (~ 20% mass %) is also found significant, and the low carbon effect in the whole life cycle means that M-NHL is environmental friendly materials. The pozzolanic effect induced by metakaolin reduces macropores and refines pore size within M-NHL system, which helps maintain high pore connectivity coefficient as well as effective porosity and more effective pathways conducive to inward transportation of CO2 gas, thereby promoting the carbonation process. [ABSTRACT FROM AUTHOR]

Although the side chain ionizability (the adsorption group density and adsorption space are changed) of polycarboxylate superplasticizer (PCE) serve as the key structural parameter in affecting the cement hydration, its effect on cement hydration is unclear. Based on PCE with nonionizable side chain (NSC-PCE) and the PCE with ionizable side chain (ISC-PCE), the influence of the side chain ionizability of PCE on the hydration behavior of cement was studied. Compared with NSC-PCE, ISC-PCE has a stronger ability to change the migration of water and ions, thus delaying the crystal nucleation and growth of cement hydration (better morphology and distribution, the crystal size was reduced by more than 20 %), increasing the crystal growth index (tendency toward spherical growth), prolonging the phase boundary reaction (reduce micro-cracks), which was conducive to the formation of more uniform and dense crystals (good strength, ISC-PCE: 50.0 MPa > NSC-PCE: 49.2 MPa > Blank: 48.7 MPa). These findings provide the design basis and theoretical guidance for the innovative development of PCE. [Display omitted] • ISC-PCE decreases the hydration rate and hydration degree of cement. • The effect of PCE on the hydration process was studied by the hydration kinetics model. • ISC-PCE has a stronger ability to change the migration of water and ions. • Proposes working mechanism in viewpoints of dissolution-precipitation equilibrium. • Tailoring the side chain ionizability was a new strategy to tune the performance of PCE. [ABSTRACT FROM AUTHOR]

• Effective modification of extruded polystyrene foam (XPSF) by the ultraviolet-ozone. • Amphipathic silane coupling agents as the adhesion promoters between XPSF and mortar. • A significant improvement on the interfacial strength of XPSF/mortar. • The chemical linkages can be induced by different kinds of silanes. The inert surface of extruded polystyrene foam (XPSF) was activated by the ultraviolet-ozone (UVO) irradiation, followed by the surface coupling reactions with γ-mercaptopropyl trimethoxysilane (MPTMS) and vinyl triethylsilane (VTEO) to improve the interfacial affinity between the organic XPSF and inorganic mortar. The reaction conditions (including reaction time, concentration and pH of the silanes) were thoroughly investigated in order to reach the maximum bonding strength (BS) of XPSF/mortar composites. It was suggested that the presence of MPTMS could increase the BS value from 0.04 MPa to 0.178 MPa (reaction time: 10 min, concentration of MPTMS: 2% and pH value of the silane solution: 4). For VTEO, the maximum BS value reached to 0.140 MPa (activation and reaction time: 7 and 3 min, concentration of VTEO: 5% and pH value of the silane solution: 7). According to the mechanism analysis, the thiol groups in MPTMS have the strongest reactivity with activated XPSF surface after UVO exposure, leading to the maximized interfacial strength between the organic insulation materials and inorganic mortar. [ABSTRACT FROM AUTHOR]

The wide application of surfactants in cement-based materials requires the understanding of the influence of surfactants on the structure and properties of C–S–H gel. In this study, cation surfactants (CTAB) and anion surfactants (SDS) in ionized type are successfully intercalated into C–S–H gel, generating different molecular models through molecular dynamics simulation. Systematic analysis and quantitative description were performed on the molecular structures, bonding properties together with deformation and fracture mechanisms. It was found that the majority of Br– ionized from CTAB could interact with Ca_interl, forming Br-−Ca_interl bonds. Smaller Na+ ionized from SDS could bond with both O_bri and O_nbri atoms, while O– and O atoms in SDS anions could interact with Ca_interl atoms as well. It is noteworthy that the intercalation of CTAB into C–S–H gel promotes the diffusion of water molecules, whereas the intercalation of SDS into C–S–H gel inhibits the diffusion of water molecules. Uniaxial tensile simulation results reveal that the breakage of both H_water–O_water hydrogen bonds and Ca_interl–O_water bonds dominates the failure process of CTAB/C–S–H gel, while the breakage of H_water–O_water hydrogen bonds governs the fracture of SDS/C–S–H gel. [ABSTRACT FROM AUTHOR]

Abstract: To make clear the environmental damages and potential improvements of Chinese cement industry, the detailed life cycle inventory (LCI) of cement manufacture with direct input and output in the boundary of cement plant as well as corresponded transport is conducted. The functional units are 1 t of Portland Ordinary cement and 1 t of clinker. The input data contain not only the traditional items such as raw materials (limestone, sandstone, ferrous tailings and gypsums), energy (coal and electricity), and admixtures (fly ash and furnace slag), but also fresh water which is not paid attention in other literature. The output data contain not only greenhouse gas (CO2) and primary pollution (NO x , PM, SO2), but also the hazardous air pollutants (HCl, NMVOC, PCDD/Fs, PAHs and fluoride) as well as noise and heavy metal emissions (As, Cd, Cr, Hg, Ni, Pb, Zn, Cu) which are usually neglected by others. The data were measured on-site. The applications of reducing pollutants and waste heat recovery technologies, and AFRs usage in cement industry are evaluated. The three steps of developments of LCI study for China cement industry are discussed. [Copyright &y& Elsevier]

[Display omitted] • EG@PDMS6-t foams have realized effective immiscible oil–water separation by selective adsorption. • EG@PDMS6-t foams can adsorb kitchen waste oil. • P20s-S0.2-EG@PDMS6-t filters show excellent oil–water gravity-driven separation performance. • The foams exhibit impressive elasticity, reusability, and resistance to chemical corrosion. 3D porous foams for oil–water separation via selective adsorption were obtained by incorporating expanded graphite (EG) granules into polydimethylsiloxane (PDMS) foams. The EG@PDMS6-t foam prepared with a PDMS:EG and NaCl:PDMS mass ratio of 6:1 and 8:1, respectively, possesses a high porosity of 80.3%, a water contact angle of 127.7°, and an oil contact angle close to 0°. The foam exhibits an impressive adsorption capacity towards light oil (hexane,6.28 g/g), heavy oil (trichloromethane, 13.33 g/g), and kitchen waste oil (4.51 g/g), being able to separate 100% of oils from an immiscible oil–water mixture and 39.0% of camellia oil and 45.3% of kitchen waste oil from oil-in-water emulsions via selective adsorption. The foams possess excellent elasticity and desirable reusability in oil–water separation and exhibit outstanding resistance to acidic and alkaline environments. EG accounts for 96.5% of the EG@PDMS6-t foam's volume. SiO 2 @PDMS hydrophobic layer was constructed on the top of EG@PDMS6-t foams by a spraying technique to tailor-make 3D filters for oil–water gravity-driven separation. The P20s-S0.2-EG@PDMS6-t filter shows an excellent immiscible trichloromethane-water gravity-driven separation, with a trichloromethane permeate flux of 11,024 L/m2h, a water rejection time of 60 s, and a separation efficiency of 99.7%. The filters are highly robust to chemical corrosion and tape-peeling. [ABSTRACT FROM AUTHOR]

The application of cement-based materials in engineering requires the understanding of their characteristics and subsequent deformation and fracture process of C–S–H gel in service. In this work, three types of amine molecules including tetraethylenepentamine (TEPA), polyacrylamide (PAM), and triethanolamine (TEA) were intercalated into C–S–H gel in an unsaturated status successfully. Systematical analysis was performed on the structures and properties for both C–S–H gel and corresponding amine molecules/C–S–H gel. It was found that the unsaturated intercalation of amine molecules into C–S–H gel plays a key role in the geometry and therein density of nanocomposites. Subsequently, radial distribution function (RDF), time-correlated function (TCF), and mean square displacement (MSD) were applied to characterize the structure and dynamic information of the as-generated nanocomposites, demonstrating the occurrence of interaction between amine molecules with Ca–Si layer and acceleration of water diffusion by unsaturated intercalation of amine molecules into the interlayer region in C–S–H gel. Finally, the deformation and fracture process of C–S–H gel and amine molecules/C–S–H gel under uniaxial tensile loads were given by molecular dynamics simulation. It was indicated that the tangent modulus of nanocomposites demonstrates a strain-softening nature, indicating a visco-elastic behavior. The breakage of Ca–O bonds and hydrogen bonds dominates the fracture of C–S–H gel. Weak interaction for TEPA/C–S–H gel or TEA/C–S–H gel leads to a decreased tensile strength. Local stress concentration in other interlayer region governs the deformation and fracture process in spite of the formation of strong interaction between double bonded polar oxygen atoms in PAM molecules and Ca atoms in C–S–H gel. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel PCE (ISC-PCE) with ionic side chains was elaborately designed and synthesized. • Good plasticizing and retention capacities were shown for wide potential applications. • Larger R h and more adsorption sites led to a gentle and continuous adsorption mode. • Introducing ionic groups into PCE side chains can greatly thicken the adsorbed layer. • Particularly designed "brush" conformation helped to improve the dispersion stability. A novel dispersant with ionic side chains (ISC-PCE) for cement slurries was elaborately designed and prepared by a simple two-step method and its molecular structure was proved. The performance test results showed that the cement paste containing ISC-PCE exhibited stronger fluidity retention (about 79.6 % after 3 h), longer free settling time (more than 3 h) and fewer flocculating structures, which presented significant dispersing stability. Furthermore, the working mechanism of ISC-PCE to cement particles was also probed via molecular conformation, adsorption, complexation ability, zeta potential and adsorbed layer measurements. It is interesting that the introduction of ionic side chains into conventional dispersant-polycarboxylate superplasticizer (PCE) molecules can achieve gentle and continuous adsorption and increase the adsorbed layer thickness (increased by 103.1 % compared to conventional PCE). The aim of this study is to offer a promising pathway to synthesize a novel PCE endowing outstanding workability stability and great rheological improvements to cement pastes by innovative molecular design. This PCE with ionic side chains has enormous promises as an effective substitute to conventional PCE with nonionic side chains, particularly in the cement paste systems with strict requirements on slump retention. [ABSTRACT FROM AUTHOR]

This study fabricated a kind of novel phase change microcapsules with a metal-polymer hybrid capsule shell for applying in gypsum materials to reduce building energy consumption. The microstructure, composition and thermal characteristics of the microcapsules were investigated by using techniques such as the scanning electron microscope, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and differential scanning calorimetry. Their impact on the thermal regulation characteristics of gypsum composite materials was also analyzed through the heating plate test and simulated room experiment. Results show the microcapsules with inner organic polymer and outer copper layer were successfully fabricated. And they exhibited a phase change temperature between 22.3 ℃ and 23.3 ℃ and latent heat between 82.2 J/g to 139.5 J/g. Meanwhile, the thermal inertia and thermal storage capacity of gypsum composites were enhanced by incorporating the final microcapsules. After heated for 40 min, the gypsum composite board with MPCM-Cu shows the ability to reduce the room temperature fluctuation. Furthermore, the thermal performance of MPCM-Cu remains stable after 250 thermal cycles. These results indicate that final microcapsules exhibit the potential for building energy conservation. [Display omitted] • MPCM-Cu with binary esters as core and polyurea-copper hybrid shell are synthesised. • The phase change temperature of MPCM-Cu is within the human comfort temperature range. • Higher MPCM-Cu content results in lower temperature fluctuation of gypsum composite. [ABSTRACT FROM AUTHOR]

In this study, the impacts of CO 2 -absorbed triethanolamine solutions (TEA-CO 2) on the mechanical property, phase composition and micro-structure of cement mortars were investigated. The results showed that TEA-CO 2 addition increased the 1d, 3d, and 28d compressive strength by 47%, 19%, and 4%, respectively, which suggests a synergistic effect of triethanolamine and absorbed CO 2 on strength development of cement mortars. The enhancement is due to TEA-CO 2 accelerates hydration of aluminate and silicate phases in early age. TEA-CO 2 facilitated CaCO 3 formation to increase cement hydration degree and modify the pore structures. However, the hydration of silicate phases was delayed slightly by TEA-CO 2 at 28d. The above results provide theoretical support for further utilization of CO 2 in cementitious materials. • Effect of TEA-CO 2 on strength development of mortars was investigated. • TEA-CO 2 addition increases flexural and compressive strength of mortars. • TEA-CO 2 accelerates the hydration of aluminate phase and silicate phase at early age. • A synergism of cement hydration and carbonation in the presence of TEA-CO 2 was proposed. [ABSTRACT FROM AUTHOR]

UV curable organic-inorganic hybrid (OIH) coatings were used to modify the extruded polystyrene foam (XPSF) surfaces to increase the bonding strengthen (BS) of XPSF/mortar composite (XMC). OIH coatings contained polyurethane acrylate, hexanediol and nanoparticles with different dimensions. With the addition of nano-SiO 2 and halloysite nanotubes, the BS-D (BS in dry state) & BS-W-2H/7D (BS in wet state after 2-hour/7-day drying) values for modified XMC were increased from 0.050 & 0.039/0.047 MPa to 0.245 & 0.196/0.356 and 0.312 & 0.233/0.323 MPa. The chemical bonding between SiO 2 /-COOH from UV coating and hydration products in mortar improved the bonding state. [Display omitted] • Modification of XPSF surface by UV curable organic-inorganic hybrid coating. • The fabrication of chemical bonding for XPSF/mortar interfaces. • The investigation of the reactions between mortar and modified XPSF surface. [ABSTRACT FROM AUTHOR]

• The hydration of glass is heterogeneous due to phase-separation structure; • The heterogeneous hydration of glass impact the formation of calcium hydroxide; • The hydration rate advantage of calcium-rich and silicon-rich phase can be reversed; • The heterogeneous hydration is suitable for thermodynamic simulation of cement paste; Supplementary cementitious materials (SCMs) affect the hydration process and long-term properties of cementitious systems. Since a large percentage of SCMs belong to alkaline-earth aluminosilicate glasses that possess a phase-separated structure, further research into their hydration characteristics is essential. This study investigated the effects of the hydration characteristics of synthetic glasses with various phase-separated structure on the phase evolution of cementitious systems by combining simulations with experiments. The results showed that with the increasing degree of phase separation, the hydration of synthetic glass transitions from homogeneous to heterogeneous hydration. The phase evolution of hardened paste, particularly for calcium hydroxide, is influenced by the difference in hydration rates among each separated glassy phase. Compared to homogeneous hydration, the rapid hydration of the Ca-rich phase reduced the consumption of calcium hydroxide, while the rapid hydration of the Si-rich phase accelerated calcium hydroxide consumption. For glasses exhibiting phase separation characteristics, the consistency between thermodynamic simulations employing a heterogeneous hydration model and experimental results exhibits a notable enhancement. [ABSTRACT FROM AUTHOR]

In this paper, star -like polycarboxylate superplasticizer (SPCE) and comb -like polycarboxylate superplasticizer (CPCE) were prepared via atom transfer radical polymerization (ATRP) to study the mechanism of the effectiveness enhancement resulting from this transformation of topological structure. It was found that SPCE molecules acted higher adsorption amount and more Ca2+ complexes, and formed a lower and more compact adsorbed layer and larger surface coverage with a flat conformation on cement surface, depending on more anchored points per unit volume. Through this mechanism, cement particles adsorbed by SPCE showed stronger dispersible capability and colloidal interaction forces (the steric force was dominant), resulting in lower yield stress and plastic viscosity of the cement paste containing SPCE which behaved as an ideal Bingham fluid. The aim of this study is to clarify the mechanistic correlation between topological structure evolution and effectiveness promotion for PCE. [Display omitted] • Topological transformation of PCE helps to enhance effectiveness via more adsorbed points per unit volume. • SPCE molecules adsorb as a flat conformation to present a low and compact layer on cement surface. • Rheological properties of cement pastes depend on the interparticle steric force which plays a dominant role. • Good agreement is shown among the measured adsorbed layer thickness, R h value and surface coverage. • Novelty changing to dense topological structure is proved as a promising way to obtain highly effective PCE. [ABSTRACT FROM AUTHOR]

• New sights on NO reduction with biomass char using Raman/XPS/XRD analysis. • Significant changes in char structures were found during the heat treatment/gasification. • Char-NO reaction and char-O 2 reaction preferentially happened following different pathways. • Relations between structural evolutions of chars and their denitration abilities were explored. NO reduction with biomass char was studied from considering its structural properties. Raman, XPS and XRD were employed to characterize the char structure. Three types of biomass chars were used for NO reduction at a fixed bed reactor in NO/O 2 at 900 ℃. The results showed that the heat treatment led to an obvious reordering of structures in all chars. There were significant differences between NO and O 2 reaction in terms of the char structural changes in aromatic systems, surface groups and crystalline developments. New O-containing groups were formed and could be present as C-O and –COO groups in both the NO and O 2 reactions. Two different pathways for char-NO and char-O 2 reaction were given, respectively. It is proposed that the reaction channel of NO would be blocked as carbon molecular was firstly surrounded by O 2 during NO/O 2 reaction. The denitration performance of biomass char should be linked to the structural features of char-HT and the behaviors of char structural changes in the subsequent gasification in NO/O 2. [ABSTRACT FROM AUTHOR]

• Graphene oxide coated tetradecanol/expanded graphite composite phase change material (TD/EG-GO) was prepared. • Porous carrier adsorption and microencapsulation technologies were combined. • TD/EG-GO showed good phase change and thermal properties due to the closed honeycomb structure. In this work, the form-stable phase change material (PCM) was prepared by absorbing tetradecanol (TD) into expanded graphite (EG). Then, the obtained TD/EG was coated with graphene oxide (GO) through electrostatic self-assembly to prepare a novel composite PCM (TD/EG-GO). The morphology, phase change and thermal properties of TD/EG-GO were fully discussed. The DSC analysis shows that the TD/EG-GO composite melts at 35.2 °C with latent heat value of 189.5 J/g and freezes at 34.9 °C with latent heat value of 187.9 J/g. The thermal cycling test results reveal that the latent heat of TD/EG-GO composite decrease by less than 1% after 500 thermal cycles, indicating that the structure of GO-coated EG efficiently prevents the leakage of TD. The thermal stability and thermal conductivity of TD/EG-GO composite are also improved compared with that of uncoated TD/EG, demonstrating the multiple benefits of surface coating of GO. [ABSTRACT FROM AUTHOR]