ENERGY & FUELS
·
2017
·
IF 3.091
Bin Chen,Feng Xin,Xiaofei Song,Xingang Li,Muhammad Zeshan Azam
CO2 capture based on hydrate formation is intensified by an oil-in-water phase-change slurry (PCS) in which the n-tetradecane particles are taken as nucleation centers and are used to directly remove the hydration heat through their solid-to-liquid phase change. In this study, experiments on hydration were conducted at a temperature of 277.6 K and under isobaric pressures in the range of 2.1–2.4 MPa. All measurements were performed at a stirring speed of 450 rpm in PCSs of 25–45 wt % n-tetradecane. Two kinetics models, transport and reversible hydration, were established to regress and analyze the experimental data from the isothermal hydration of CO2 in a semibatch hydrator. For each model, the effects of pressure and PCS composition were examined in detail. As the experimental results show, the induction time before hydration initiated was less than 1 min for all runs, and the duration of the entire hydration process was approximately 13–15 min for each measurement. Furthermore, the average hydration rate reached 197 mol m–3 min–1 at 2.3 MPa in 45 wt % oil-in-water PCS, which demonstrates that the presence of n-tetradecane particles contributes significantly to the enhancement of hydrate formation rate. As the modeling results show, the parameters of the two models were determined by correlating the experimental data, and the interpretations of the measurements by the two models are satisfactory.
研究领域:
化学工程
·
环境科学
·
能源技术
✓ 已验证
产品关联
DOI
高影响因子
CEMENT AND CONCRETE RESEARCH
·
2021
·
IF 10.933
Xueyu Pang,Lijun Sun,Fang Sun,Ge Zhang,Shenglai Guo,Yuhuan Bu
The heat evolution during the hydration of cement was examined by multiple calorimetric methods: isothermal , oscillating isothermal, as well as temperature scanning tests in the temperature range from 15 °C to 95 °C. The apparent activation energy ( E a ) of several different types of cements were all found to decrease significantly with temperature. Type of additives and water to cement ratio had little influence on the temperature dependence of E a . The correlation between E a and temperature may be mathematically simplified to a step function, where E a is a nonzero constant below a critical temperature ( T cr ) and reduces to zero above that temperature. The proposed model of E a was combined with a scale factor model to simulate the influence of curing temperature on the hydration kinetics of cement with significantly improved accuracy compared to an earlier model.
研究领域:
材料科学
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Research and Technology-JMR&T
·
2022
·
IF 6.267
Liguo Wang,Yu Zhang,Le Guo,Fengjuan Wang,Siyi Ju,Shiyu Sui,Zhiyong Liu,Hongyan Chu,Jinyang Jiang
Studying the mechanism by which organic admixtures affect the hydration and dissolution of tricalcium silicate (C 3 S) reveals the effect of organic admixtures on ordinary Portland cement and enables target regulation of cement-based materials. In this study, the effects of citric-acid-modified chitosan (CAMC) on the hydration exotherm, hydration products, and microscopic morphology of C 3 S were investigated. The interface structures, ion adsorptions, and dissolution properties of CAMC and C 3 S were analyzed using a molecular dynamics simulation method. The results showed the presence of an attraction between the C 3 S surface and CAMC due to the existence of O p -H w , O p -Ca s , and H p -O w ion pairs. CAMC adsorbed most of the Ca ions released upon dissolution of C 3 S in the aqueous solution and the resulting pairs exhibited low solubilities. The Ca ions were located on the surfaces of C 3 S particles, preventing the dissolution of the particles and proving the interference effect of additives on the hydration of the cement silicate phase.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Guodong Zhang,Zhe Liu,Daming Liu,Yan Lin,Fei Wang
The volume penalty of nano-porous materials causes low methane volumetric adsorption capacity, and the contradiction between it and gravimetric adsorption capacity limits the application of nano-porous materials in different scenarios. Here, we prepared a composite nano-porous material of ZIF-8@AC to bridge the gap using a synergistic approach of adsorption and hydration, and methane isothermal adsorption in wet ZIF-8@AC was evaluated under low temperature. Due to the hybrid effect of adsorption and hydration, methane storage capacity in the nano-porous material was enhanced. When 100 mg activated carbon was doped, methane gravimetric adsorption capacity in ZIF-8@AC increases by 6.78 % and 30.34 % comparing with that in parent AC and ZIF-8 separately. In addition, the formation of hydrate increases methane storage density in mesopores, macropores and intergranular pores, giving rise to large methane volumetric adsorption, which increases by 12.65 % and 53.24 % comparing with that in parent AC and ZIF-8, respectively. Moreover, hydration efficiency in confined pore space was investigated by differential scanning calorimetry (DSC), while a high-resolution electron microscope was applied to record hydrate morphologies. It was found that hydrate mainly forms in large pore spaces, and the enhanced intergranular pores serve as nanoreactors to significantly improve the hydration efficiency, which is greatly influenced by local water distribution. These findings provide a new strategy to enhance methane adsorption via adsorption and hydration hybrid approach and would shed light on the application of composite nano-porous materials in the adsorption of natural gas.
研究领域:
材料科学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
LANGMUIR
·
2023
·
IF 3.9
Changhao Bing,Xubin Zhang,Fumin Wang,Yi Zhai,Yongwang Li,Kaiwei Wang,Xiaolu Fan,Jinjin Zhang,Qi Shen,Xinyuan He
Zeolite is considered an ideal catalyst for olefin hydration due to its high specific surface area and abundant acid sites. However, the immiscibility of the water–oil two phases in olefin hydration limits mass transfer, and the side reaction of etherification occurs acutely, resulting in a low yield of alcohol. Thus, water–oil amphiphilic HZSM-5 was prepared by sulfonating silanized zeolite. The successful introduction of organic and sulfonic acid groups is demonstrated by FT-IR, TG, and water contact angles. Amphiphilic HZSM-5 can stabilize the Pickering emulsion and catalyze cyclopentene hydration at the phase interface. In addition, NH3-TPD and Py-IR show that the amount of strong Bro̷nsted acid sites of zeolites increases significantly after sulfonation. This facilitates the rate-determining step of cyclopentene activation by H+ to form carbocation. Moreover, the nucleophilic side reactions are inhibited by a high concentration of H+. Finally, under the optimized reaction condition, the conversion of cyclopentene can achieve 5.066% with a selectivity of 85.37% to cyclopentanol, which almost reaches the reaction equilibrium.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Shuai Li,Yaowu Wei,Bingrong Li,Xiujuan Wang,Junfeng Chen
The phase composition, microstructure, and hydration process of C 3 A with different MgO content were compared to elucidate the mechanism of hydration resistance of CaO improved by MgO–C 3 A solid solution . The process of hydration heat release was detected by isothermal calorimetry and the hydration products were analyzed by X-ray diffraction and scanning electron microscope. The results showed that the addition of MgO resulted in lattice distortion of C 3 A. In the middle and late stages of the hydration process, Mg(OH) 2 and amorphous gel-like substances covered the surface of the unreacted C 3 A and reduced the hydration reaction rate. The addition of MgO effectively reduced the hydration activity of the MgO–C 3 A solid solution that indicated the addition of MgO can improve the hydration resistance of CaO materials.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2014
·Vol. 4
·期 83
·44018-44025
·
IF 3.708
Qinyu Ren,Huawei Zou,Mei Liang,Yongmei Wang,Jinchun Wang
A series of comb-like polymer, amphoteric polycarboxylic (APC), was designed as a dispersant for portland cement. APC was synthesized in aqueous solution by macromonomer of butenyl alkylene polyoxyethylene-polyoxypropylene ether (BAPP), sodium methacrylate (SMA), acrylic acid (AA) and [2-(methacryloyloxy)ethyl]trimethylammonium chloride solution (MAEAC). The molecule structure of amphoteric polycarboxylic dispersant was characterized by Fourier transformer infrared (FTIR), and the molecular weight of the APC was determined by gel permeation chromatography (GPC). The dispersion capacity of the APC in cement was also measured. The result shows that the amphoteric polycarboxylic dispersion agent is suitable for portland cement. The APC dispersant with both anionic group and cationic group will provide the better anchoring action with the cement via the adsorption of ions. The hydration mechanism of cement with a certain amount of APC is discussed. We found that the APC could affect the hydration process, which was performed through retarding the generation of ettringite and affecting the crystal enthalpy and its thermal stability in the hydrated product.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Journal of Macromolecular Science Part A-Pure and Applied Chemistry
·
2019
·
IF 1.163
Yeyun Meng,Bing Liao,Kun Wang,Fuwei Nian,Huiyi Wang,Hao Pang
A new series of poly (AA-co-β-CD-A-co-TPEG) (PACDs) copolymers were prepared by the copolymerization of a novel monovinyl β-cyclodextrin monomer (β-CD-A), acrylic acid and isoprenyl oxy polyethylene glycol (TPEG-2400), which could be used as superplasticizers and shown excellent dispersion ability. Therefore, this work mainly investigated the adsorption behavior, dispersing properties as well as hydration behavior of cement pastes. Optical microscopy was employed to describe dispersing performance. X-ray diffraction (XRD) and TGA/DTG were utilized to account for the cement hydration process. We found that the PACDs with β-CD-A exhibited outstanding dispersion ability. In addition, the performances of the PACDs were monitored by evaluating the setting time and fluidity of the cement paste. The results clearly shown that the setting time was longer and slump loss was smaller than that of PACD0 that without β-CD-A. Therefore, PACDs with the proper content of β-CD pendants had excellent performances due to the steric hindrance of the CD moieties.
研究领域:
材料科学
·
土木工程
·
高分子化学
·
水泥水化
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS IN CIVIL ENGINEERING
·
2019
·Vol. 31
·期 5
·04019041
·
IF 1.984
Kuangyi Hu,Zhenping Sun,Haijing Yang
Effects of polycarboxylate superplasticizers (PCEs) with different functional units on the flowability, hydration heat, and hydration products of cement paste were investigated. Two kinds of functional units, the sulfo unit and the amide unit, were mentioned, and four series of PCEs with different monomers were synthesized. It was proved that different functional units had varying influence on fluidity, induction period, heat flow peak, and the amount of hydration products of cement paste. Moreover, a modified model for explaining cement paste hydration with PCEs was propounded to describe the aforementioned effects.
研究领域:
建筑材料
·
水泥化学
·
混凝土用聚合物添加剂
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS IN CIVIL ENGINEERING
·
2025
·Vol. 37
·期 8
·04025258
·
IF 3
Yimu Wang,Jinqing Jia,Dingming Zhang,Xing Gao
In this research, the impact of calcium formate (CF) on the hydration process of tricalcium silicate (C3S, the most abundant component in portland cement) was investigated by setting time test, compressive strength test, isothermal calorimetry, X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy energy-dispersive spectroscopy (SEM-EDS). The incorporation of CF led to a decrease in setting times and enhanced early strength of the C3S specimen. Furthermore, the heat release of the C3S sample was increased by the addition of CF. Results from XRD and TGA indicated that the hastening of solidification and the rapid development of initial strength in C3S pastes by CF was not due to its promotion of C3S hydration level. On the contrary, CF impeded the initial hydration process of C3S. However, the study of the hydration level of C3S revealed that the incorporation of CF led to a noticeably greater water-to-silica ratio (H/S) in the calcium silicate hydrate (C─ S─ H) phase, primarily as a result of water molecules infiltrating the C─ S─ H. This elevated H/S ratio in C─ S─ H contributed to a rise in the volume of water utilized throughout the hydration process of C3S for each unit, which stands as the principal factor behind the hastened setting and the initial strength increase observed in C3S paste due to the presence of CF.
✓ 已验证
DOI
高影响因子
CEMENT AND CONCRETE RESEARCH
·
2024
·
IF 10.9
Qing Liu,Xing Ming,Miaomiao Wang,Qiao Wang,Yunjian Li,Zongjin Li,Dongshuai Hou,Guoqing Geng
The early hydration of Portland cement is profoundly affected by the mineral phase of tricalcium aluminate (C 3 A), but how in situ polymerization of monomers influences the hydration of C 3 A remains unclear. Herein, we probed the effect of in situ polymerization of acrylic acid (AA) on the hydration behavior of cubic C 3 A from experiment and ab initio molecular dynamics simulation (AIMD). Our findings reveal that in situ polymerization of AA retarded C 3 A hydration, which was corroborated by the AIMD result that polyacrylic acid (PAA) reduced the charge transfer between C 3 A and water and inhibited the dissolution of Ca ions from C 3 A surfaces by adsorbing on the C 3 A. Additionally, in situ polymerized PAA improves the carbonation resistance of C 3 A hydrates, accompanied by lowering their crystallinity. Hopefully, our findings can provide valuable guidance on the theory for implementing in situ polymerization of monomers in cement-based materials.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2016
·
IF 2.421
Fan-rong Kong,Li-sha Pan,Chen-man Wang,De-la Zhang,Nai Xu
Effects of polycarboxylate (PCE) superplasticizers with different densities of carboxylate groups, functional group contents, molecular weight, and side chain polymerization degrees on the hydration behavior of Portland cement were investigated in this study. The experiments were conducted by using semi-adiabatic calorimeters equipped with a temperature measurement system. The water cement ratio (W/C) was 0.4, and the PCE dosage used was 0.3%. Besides, the Total Organic Carbon (TOC) experiments were taken to further study the delaying mechanism of different PCE on cement hydration. The ability to delay hydration increased in PCEs with high densities of carboxylate groups, short side chains, and high molecular weight and the copolymerization of methyl acrylate (MA) monomers decreased the heat flow peak. Nevertheless, the main hydration temperature peak and the maximum elevated temperature decreased when the density of the carboxylate groups increased. Moreover, PCEs with only a moderate molecular weight had the lowest hydration degree. The main hydration peak decreased but appeared in advance when the amount of MA monomers copolymerized with PCEs was increased; the hydration degree also decreased. PCEs only polymerized by methyl allyl polyethenoxy ether (TPEG400) macromonomer had a hydration degree of 69.46%. Absorption amount results indicate that PCEs affect the hydration of cement paste by absorbing PCEs on the surface of cement particles or encapsulating some cement particles to restrain cement hydration. PCEs grafted with MA hydrolyzed to carboxylic and hydroxyl groups, which can both restrain the hydration of cement paste.
研究领域:
建筑材料学
·
化学工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）