Materials
·
2022
·Vol. 15
·期 13
·4599
·
IF 3.748
Jing Li,Lang Yang,Feng Rao,Xiang Tian
Geopolymers have attracted extensive attention in the marine environment because of its special reticulate nanostructure. Gel evolutions of copper tailing-based green geopolymers were studied under air, deionized water, seawater, freeze–thaw cycle and carbonization environments. Their mechanical properties and microstructures were characterized by compressive strength measurement, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) and scanning electron microscopy (SEM). It was found that the deionized water and natural marine water exposure promoted the evolution degree of geopolymers and improved their compressive strength, while exposure to the carbonization environment weakened the gel evolution and decreased the cross-linking degree of the Sodium aluminosilicate hydrate (N-A-S-H)gel structure, resulting in a decline of compressive strength. The geopolymer exposed in the freeze–thaw cycle exhibited the worst deterioration due to the expansion caused by the crystallization in the geopolymer. These results are essential and beneficial to further understanding the gel formation process in various marine environments and could promote the investigation of green concrete.Keywords:geopolymer;marine concrete;compressive strength;carbonization;corrosion resistance
研究领域:
材料科学
·
海洋工程
✓ 已验证
DOI
PubMed
高影响因子
Colloid and Interface Science Communications
·
2021
·
IF 4.914
Haize Jin,Youyou Zhang,Qikun Wang,Qibing Chang,Cuixia Li
Ongoing researches about adsorption removal of heavy metal ions and dyes are targeted to improve adsorption efficiency and recycle to solve environmental problems. Geopolymer as an adsorbent for wastewater treatment exhibits a good application potential. Here, a rapid removal strategy for methylene blue (MB) and nickel ions based on metakaolin-based geopolymer (MG) is provided. The adjustment of pH allows the MG to expose more negative charge adsorption sites, resulting in rapid removal of MB and Ni 2+ . The adsorption data fitted well by the pseudo-second-order model and Langmuir model, indicating the chemisorption of MG for MB and Ni 2+ . The decrease of pH of wash solution is conducive to the desorption of Ni 2+ . However, the desorption of MB-loading MG proved to be very difficult. This study provides a universal reference and possibility for rapid removal of cationic dyes and heavy metal ions under relatively mild conditions.
研究领域:
环境科学
·
材料科学
·
化学工程
·
水处理
✓ 已验证
产品关联
DOI
高影响因子
Arabian Journal of Chemistry
·
2020
·
IF 4.762
Zefeng Yu,Weifeng Song,Jiayao Li,Qiuhua Li
In this paper, a metakaolin-based mesoporous geopolymer (GP-CTAB) was used as adsorbent for Cu(II) and Cr(VI) through a novel and simple synthetic route using cetyltrimethylammonium bromide (CTAB) as an organic modifier. The application of GP-CTAB for the simultaneous removal of metal anions and cations in aqueous solution was studied for the first time. The results of X-ray diffraction (XRD) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Brunauer, Emmett and Teller (BET), and Barrett, Joyner, and Halenda (BJH) methods indicate that GP-CTAB is still geopolymer even in the presence of quaternary ammonium salt cations. The material was tested to simultaneously adsorb Cu(II) and Cr(VI) from an aqueous solution. The results show that GP-CTAB can adsorb anions simultaneously without sacrificing the adsorption properties of heavy metal cations, which is superior to conventional geopolymers. The maximum theoretical adsorption capacity of GP-CTAB for Cu(II) and Cr(VI) was 108.2 mg/g and 95.3 mg/g in the binary system, respectively. It was also found that the presence of Cu(II) in the solution promoted the adsorption of Cr(VI). Given this characteristic of GP-CTAB, it has shown great application prospects in the prevention and control of heavy metal pollution.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Jingkun Yuan,Peigang He,Xiaomin Liang,Dechang Jia,Lingyu Jia,Delong Cai,Zhihua Yang,Xiaoming Duan,Shengjin Wang,Yu Zhou
In this paper, a high temperature treatment procedure was designed to evaluate the effect of holding temperature on thermal evolution process of Li + substituted Cs-based geopolymer (Cs 0.7 Li 0.3 GP), including the thermal analysis, phase composition and microstructure evolution. With rising of holding temperature, amorphous unheated Cs 0.7 Li 0.3 GP gradually transformed into a multiphase system during the high temperature treatment process, which consisted of pollucite (CsAlSi 2 O 6 ), spodumene (LiAlSi 2 O 6 ) and amorphous glass phase. In the multiphase system, Cs + ions were in the form of pollucite grains, while Li + ions were in the form of spodumene nanocrystallines distributed in amorphous matrix. The pollucite grains gradually coarsened with rise in holding temperature, and the densification of the resulting products were also improved synchronously, which were related to the presence of amorphous glass phases. The amorphous glass phase would be in a molten state when holding temperature over 800 °C. And the presence of molten amorphous phase would make the mass transfer process easier, which could contribute to the growth of the crystal grains and the elimination of the pores.
研究领域:
材料科学
·
地质学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Chunyan Huang,Zichen Li,Yuning Pan,Zhili Li,Yuanyuan Ge
Developing efficient dual functional membranes through simple methods to remove various water pollutants remains challenging. Herein, a dual functional geopolymer/copper mesh membrane (GM/CM) was fabricated by one-step coating for oil–water separation and dye degradation. The geopolymer coating, serving as armor, improved hydrophilicity and pore structure, enabling rapid pollutant adsorption and degradation via advanced oxidation processes (AOPs) while inhibiting copper ion leaching. The GM/CM had a water flux of 4936 L m −2 h −1 bar −1 and demonstrated a separation efficiency of over 99 % for five different oil–water emulsions. Copper ions in GM/CM, with multiple valences, could efficiently catalyze reactive oxygen species production from H 2 O 2 . In batch mode, the GM/CM + H 2 O 2 system removed 98.48 % of methylene blue (MB) in water with 1 O 2 as the primary active species. Multiple anions had no significant impact on the degradation efficiency of the GM/CM + H 2 O 2 system. In filtration mode, the GM/CM + H 2 O 2 system achieved over 98 % removal of MB within a continuous 180 min period. Compared to other membranes, GM/CM had both high flux and competitive removal efficiencies. Moreover, due to the ion exchange and chelating effects of the geopolymer armor, the leaching concentration ratio of copper ions was two orders of magnitude lower than that in the unarmored catalyst CM + H 2 O 2 system, and significantly below the standard limit and the results reported in other literature. Overall, this work shows the potential application of GM/CM in water treatment and offers a new method for convenient preparation of dual functional membranes.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Yili Zeng,Nan Duan,Caiping Fu,Dejin Liao,Xiaolan Song,Shengming Jin,Kuixin Cui
Using tailings to prepare constructive materials is of great significance for sustainable development of mineral processing industry. In this study, the possibility of preparing tungsten tailing-based geopolymers was explored in detail. XRD , FTIR , PLM, SEM and XPS analyses were carried out to characterize the phase composition, chemical bonding, microstructure, chemical state, and interface properties of tungsten tailing-based geopolymers. Results showed tungsten tailings presented little activity using NaOH as activator, while geopolymers with 60% non-pretreatment tungsten tailing and 40% metakaolin presented a 3-day compressive strength of 8.4 MPa and 28-day compressive strength of 9.1 MPa. The geopolymerization products of tungsten tailing-based geopolymers were N-A-S-H gels and aluminosilicate zeolite crystals, while tungsten tailings were wrapped by metakaolin-derived geopolymerization phases as aggregates with interfaces containing Si–O–Si bonding between quartz in tungsten tailings and zeolite and/or gel phase in metakaolin-derived geopolymer in the geopolymerization process. Besides, the leaching test results indicated that the immobilization efficiency of T6M4 geopolymers for Mn and Pb derived from tungsten tailings reached up to 97.28% and 99.95%, respectively. This research results provide a new idea for utilization of tungsten tailings on a large scale.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2019
·
IF 7.65
Peigang He,Jingyi Cui,Meiling Wang,Shuai Fu,Hualong Yang,Chengyue Sun,Xiaoming Duan,Zhihua Yang,Dechang Jia,Yu Zhou
Notwithstanding the success of carbon-free nuclear power in the new energy industry, an effective way to address nuclear contamination is still lacking. As a generally accepted method to date, immobilization of radioactive nuclear wastes with inexpensive and environment-friendly matrix such as geopolymer has attracted extensive attention. In this contribution, Na-based and K-based metakaolin geopolymer were prepared to encapsulate simulated radioactive Cs + and Sr 2+ under different temperatures and environments during long-term leaching tests. The temperature-dependent and environmental-dependent leaching kinetics as well as their dominant leaching mechanisms have been revealed. The results showed that Na-based and K-based geopolymer exhibited better immobilization performance than that of Portland cement, ceteris paribus. For the immobilization of Cs + , Na-based geopolymer showed lower leaching rate than K-based geopolymer under the same leaching conditions. Both higher temperature and salt solution accelerated the leaching behaviors of Sr + and Cs 2+ from the encapsulation matrix. This contribution sheds light on understanding the dominant leaching mechanisms of hazardous elements under different storage environments and highlights the significance of salt-tolerant matrix for the immobilization of nuclear wastes.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2017
·Vol. 100
·期 10
·4412-4424
·
IF 2.841
Jingkun Yuan,Peigang He,Dechang Jia,Jinsong You,Xuzhao Liu,Yao Zhang,Delong Cai,Zhihua Yang,Xiaoming Duan,Shengjin Wang,Yu Zhou
As part of a series of studies, effects of Na + substitution on the thermal evolution of cesium-based geopolymers on heating were studied. A series of sodium-substituted cesium-based geopolymers, Cs (1− x ) Na x GPs (where x =0, 0.1, 0.2, 0.3, and 0.4), were prepared and treated at 1300°C for 2 hours to obtain the corresponding ceramic products. The thermal evolution process was disclosed by virtue of a variety of technical, including TG-DTA, thermal shrinkage, XRD analysis, SEM, and TEM investigation. The results indicated that unheated Cs (1− x ) Na x GPs was not completely amorphous after the substitution of Na + and the crystallinity of Cs (1− x ) Na x GPs gradually increased with the rise of sodium content. Meanwhile, the average particle sizes of Cs (1− x ) Na x GPs also increased evidently with increases in sodium substitution. The final product after heat treatment mainly consisted of pollucite (CsAlSi 2 O 6 ) and amorphous glass phase. The particle size of pollucite grain gradually decreased as more Cs + were replaced maybe owing to the role of Na + in the nucleation process of pollucite. Two forms of Na + present in the final products: A small portion was present in the pollucite grains due to Na + partial occupied the crystallographic sites of Cs + ; and the rest were present in the amorphous glass phase among the pollucite grains. The average coefficient of thermal expansion (CTE) of resulting Cs (1− x ) Na x GPs ceramics increased from 4.80×10 -6 K −1 ( x =0) to 7.26×10 −6 K −1 ( x =0.4) with increases in sodium substitution, which could be due to the amorphous glass phase had a relatively higher CTE than that of pollucite.
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
Materials
·
2024
·Vol. 17
·期 17
·4409
·
IF 3.1
Yuxiang Chen,Shengping Wu,Hanhui Huang,Feng Rao,Lang Yang
This study aims to compare the effects of three calcium compounds on the workability, setting time and mechanical properties of red mud (RM)–blast furnace slag (BFS)-based geopolymers. The crystalline phase, hydration process and microstructure of RM-BFS-based geopolymers were characterized by X-ray diffraction (XRD), heat evolution, X-ray photoelectron spectroscopy (XPS), and scanning electron microscope (SEM) tests. The results showed that an appropriate amount of calcium compounds can improve the flowability and compressive strength of the geopolymers, but the excessiveness causes a decrease in strength due to rapid hardening. Other than calcium carbonate, both calcium oxide and calcium chloride played important roles in accelerating the setting times of RM-BFS-based geopolymers. The acceleration in the setting times of geopolymers could be attributed to the calcium hydroxide produced by the dissolution of the calcium compounds, which also provides nucleation sites for the geopolymerization reaction. This study gives new insights into the effect of calcium on the setting times and mechanical properties of geopolymers in the geopolymerization process.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2021
·
IF 6.141
Yuan Fang,Aoxuan Wang,Keze He,Hongying Pan,Jiajun Liao,Zhu Ding,Feng Xing,Huirong Le,Xianfeng Wang
This article investigates the key interface properties of geopolymers reinforced by SiC whiskers loaded with BN coating (BN/SiCw) and the insight of mechanical performance and microstructures of the resulting composites. The interesting diverse strength evolutions of geopolymer composites calcinated at various temperatures suggest a result of rivalries of multiple factors including BN coating, geopolymer matrix transformations, SiC whiskers. A positive effect on whisker pull-out phenomenon has been achieved via the chemical bonding between SiC whisker (SiCw) and BN coating and the rough physical interface between BN coating and geopolymers; the addition of SiCw and BN/SiCw promotes the polycondensation reaction of geopolymers and the addition of the latter is superior. Through changing the pore structure characteristics of the composites, the SiCw in composites can release their excessive vapor pressure in the closed pores which is the main reason attributing to the strength loss of geopolymers at 900 °C. In addition, BN coating can make up for the mismatch of thermal expansion coefficient between SiCw and geopolymers, increasing the strength of the composites by 30.9% at 900 °C, whereas whisker pull-out and crack deflection are the main toughening effect for BN/SiCw.
研究领域:
材料科学
·
工程学
✓ 已验证
DOI
高影响因子
CEMENT & CONCRETE COMPOSITES
·
2022
·
IF 9.93
Wei Chen,Alicia C. Garofalo,Haining Geng,Yan Liu,Dongwen Wang,Qiu Li
Cesium-based geopolymer is more refractory than K + and Na + based geopolymers after the transformation to ceramic material, whose thermal resistance feature is highly appreciated by some industries, especially in the engineering field where the materials in some cases are exposed to environments with high temperatures. In this study, cesium-activated geopolymer composites (CsGPc), with 5–35 wt% cordierite reinforcements, were prepared and evaluated on the high temperature performance. When 35 wt% cordierite was added, the compressive strength increased by 72% compared to the reference plain CsGP. Residual compressive strength (after heating at 1400 °C) of CsGPc with 35 wt% cordierite increased by 106% compared to the specimen before the thermal exposure . After thermal exposure up to 1400 °C, the geopolymer matrix was transformed into a pollucite-based ceramic composite. Amorphous phases in CsGPc gradually crystallized to form pollucite as the main phase with cordierite as secondary phase. The microstructure of CsGPc and the obtained ceramics showed a clear sintering process and crystallization of pollucite. Shrinkage was reduced and the coefficient of thermal expansion (CTE) varied from 4.50 to 1.89 × 10 −6 K −1 with the cordierite inclusion. The performance of obtained ceramic composites was superior compared to the initial CsGPc, which would be excellent for heat resistance applications.
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
Minerals
·
2020
·Vol. 10
·期 9
·832
·
IF 2.38
Jie Wu,Jing Li,Feng Rao,Wanzhong Yin
In this study, copper slag reprocessing tailings (CSRT) were synthesized into geopolymers with 40%, 50% and 60% metakaolin. The evolution of compressive strength and microstructures of CSRT-based geopolymers in a marine environment was investigated. Except for compressive strength measurement, the characterizations of X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) and scanning electron microscopy (SEM) were included. It was found that marine conditions changed the Si/Al ratio in the sodium-aluminosilicate-hydrate (N-A-S-H) gel backbone, promoted the geopolymerization process, led to moreQ4(3Al),Q4(2Al) and Q4(1Al) gel formation and a higher compressive strength of the geopolymers. This provided a basis for the preparation of CSRT-based geopolymers into marine concrete.Keywords:copper slag reprocessing tailings;geopolymer;microstructure;NMR
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）