CEMENT & CONCRETE COMPOSITES
·
2022
·
IF 9.93
Xingyi Zhu,Chenghong Lu,Wenkai Li,Siqi Zhou,Feng Li,Jianzhuang Xiao,Surendra P. Shah
This paper discusses the different modifying mechanisms of carbon nanofiber (CNF) on the geopolymers with different calcium contents . First, the rheological and mechanical properties of CNF modified geopolymers with low and high-calcium content are measured. Results show that the modifying effect on rheological properties is more obvious on high-calcium geopolymers. The compressive and flexural strength of low-calcium geopolymers decrease, while the compressive and flexural strength of high-calcium geopolymers significantly improve. Based on XRD , MIP , and SEM analyses, it can be concluded that CNFs help to produce refined hydration products in high-calcium geopolymers, resulting in a denser structure. Promoting hydration can counteract the adverse effect caused by the agglomeration of CNFs. CNFs have a positive effect on high-calcium geopolymers in general. However, hydration reaction rarely happens in the low-calcium geopolymers because of the low calcium content, and XRD results show that CNFs do not significantly promote the geopolymerization reaction. Moreover, the agglomeration of CNFs leads to a decrease in compactness. CNFs negatively affect low-calcium geopolymers. Generally, CNFs can be applied in high-calcium geopolymers to form a denser structure and improve the mechanical properties.
研究领域:
材料科学
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土木工程
✓ 已验证
DOI
高影响因子
International Journal of Applied Ceramic Technology
·
2022
·Vol. 20
·期 2
·906-916
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IF 2.328
Lingyu Jia,Peigang He,Dechang Jia,Jingkun Yuan,Delong Cai,Daxin Li,Xiaoming Duan,Zhihua Yang,Yu Zhou
Sr-containing ceramic products produced from geopolymer, (Na, Sr)-GP, have been reported as excellent candidate materials for the immobilization of radionuclide 90Sr, despite sintering temperature at 1200°C. In this work, the product possessing the best immobilization performance (leaching rate of 1.29% for Sr 2+ ) can be produced at 1000°C in the method of liquid-phase sintering via the addition of fluxing agent B 2 O 3 at 2.0 wt% in the geopolymer precursor. The mechanical properties of the geopolymer precursor (Na, Sr)-GP were also enhanced via the promotion role of B 2 O 3 to geopolymerization. It was revealed that the overall anti-leaching ability of the Sr-containing ceramic product not only depends on the microstructure of the loading substrate but also can be affected by the chemical state of radioactive strontium retention in the loading matrix.
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
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 39
·18839-18847
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IF 3.925
Hongxia Chen,Haiyan Yan,Peiyu Cao,Yufeng He,Pengfei Song,Rongmin Wang
Semicoke (SC) is a kind of powder of industrial by-products that easily cause environmental pollution due to the presence of stable organic matter in clay minerals. In this work, a porous magnetic semicoke-based geopolymer (MSC-GP) was prepared using SC as the raw material. Then, 2-methyl-4-chlorophenoxyacetic acid (MCPA), a typical herbicide, was loaded into the porous MSC-GP and composited with sodium alginate (SA) using calcium as a crosslinking agent, which afforded MSC-GP/SA encapsulating MCPA (MCPA@MSC-GP/SA). The structure and micromorphology of SC, SC-GP and MCPA@MSC-GP/SA were characterized by FT-IR spectroscopy, TG-DTG, SEM and EDS. After measuring the swelling behavior in water and saline solutions, the water retention capacity, pH effect, degradation efficiency, site-specific targeted release, recovery, slow-release behavior, and pot experiments of MCPA@MSC-GP/SA were assessed. This indicated that the water retention capacity of soils was improved by the addition of MCPA@MSC-GP/SA. The release rate of the herbicide in MCPA@MSC-GP/SA was 65.2% in 90 days, which indicated that MCPA@MSC-GP/SA possessed a higher utilization efficiency and control of weeds compared to traditional herbicide. In summary, this study opens up a new avenue for improving the utilization efficiency of SC and prolonging the duration of herbicide action, which may have potential applications in agricultural production.
研究领域:
环境科学
·
农业科学
✓ 已验证
产品关联
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2021
·
IF 7.963
Peigang He,Qikun Wang,Shuai Fu,Meiling Wang,Shengjian Zhao,Xuzhao Liu,Yuqi Jiang,Dechang Jia,Yu Zhou
This paper reports a facile route to prepare bulk zeolites with tunable phase compositions and microstructures by combining hydrothermal treatment and geopolymer precursor technique. Amorphous Na-based geopolymer (NaGP) is transformed into crystalline analcime following hydrothermal treatments. By systematically investigating the effects of hydrothermal conditions on the phase compositions and microstructures of the products, the optimal hydrothermal procedure is screened as treating NaGP in 1 M NaOH solution at 160 °C for 6 h. Furthermore, we achieve control over phase compositions of the resulting bulk zeolites by tailoring the initial Na/K ratio of geopolymer precursors. For instance, treating the geopolymer precursor with a Na/K ratio of 9: 1 under the optimal hydrothermal procedure leads to the formation of zeolite consisting of analcime and zeolite-P. The as-prepared adsorbents exhibit outstanding adsorption performance for the hazardous elements, among which analcime-zeolite-P shows an adsorption efficiency of 93.3% for Cs + , and NaGP exhibits an adsorption efficiency of 99.6% for Sr 2+ . Moreover, we reveal the mechanisms underlying the adsorption of Cs + and Sr 2+ in the adsorbents to be chemisorption . Meanwhile, ion exchanges also occur in NaGP and analcime-zeolite-P during Cs + adsorption. These results render geopolymers and their derived bulk zeolites promising for hazardous elements adsorption.
研究领域:
材料科学
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环境科学
✓ 已验证
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
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Lingyu Jia,Tingting Yang,Zixu Chen,Xingqi Liao,Peigang He,Dechang Jia,Xiaoming Duan,Zhihua Yang,Yu Zhou
In this work, we utilized an in-situ chemical synthesis method to fabricate a Fe 3 O 4 /K-geopolymer (KGP) composite to be applied in a microwave absorbent field. This material, as a type of ceramic precursor, is highly expected to be a 3D printing material to prepare microwave absorbing components with complex shapes. The investigation results demonstrate that the material possesses a large effective microwave absorbing bandwidth of 3.7 GHz with the minimum reflection loss reducing to −12.2 dB when the generated Fe 3 O 4 percent reaches 12 wt% in the KGP composite. This microwave absorbent performance can be attributed to a synergistic effect between the eddy current loss caused by the improved electrical conductivity of magnetic nanoparticles and the interfacial polarization effect from the geopolymer matrix and magnetic medium interface. Also, we used direct ink writing technology to print two-dimensional components with desirable patterns. Thickness-dependent wave absorption evaluation results confirmed a maximum reflection loss of −25.9 dB at 15.2 Hz was obtained from the printed sample containing 9.0 wt% Fe 3 O 4 for a layer thickness of 10 mm, indicating that wave consumption effectiveness was determined by porous microstructures, magnetic loss of Fe 3 O 4 nanoparticles as well as suitable impedance matching. The preparation method and synthesized material pave the way for integrated manufacturing of 3D printing components with microwave absorbing performance.
研究领域:
材料科学
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电磁学
·
制造工程
✓ 已验证
DOI
高影响因子
Journal of Building Engineering
·
2025
·
IF 7.4
Rongfeng Gao,Jiaxi Mao,Shengqian Ruan,Yilu Qiu,Shenhao Ye,Shikun Chen,Yi Liu,Dongming Yan
Eco-friendly geopolymers have demonstrated highly effective in immobilising organic liquid wastes, even outperforming Portland cement-based materials. To evaluate the feasibility of reusing liquid waste-containing geopolymers, this study systematically investigated the effects of immobilising three categories of organic liquids, i.e., vegetable oil, mineral oil, and organosilicon liquids, on the strength, wettability, water absorption, multi-scale pore structure, and chemical composition of metakaolin-based geopolymers (MKGs). Results indicate that mixing 18 % vegetable oil has minimal impact on the early-age (3 and 7 d) compressive strength but reduces long-term (28 d) strength by 29.2−34.9 %. Vegetable oil generally exists as small spherical droplets (10−50 μm) within the MKG matrix, acting as hydrophobic fillers that reduce the water absorption rate by 78.0−83.2 %. In contrast, mineral oil with low dosages of <4 % enhances the 28-d compressive strength by up to 20.4 %. Mineral oil tends to aggregate into larger droplets (20–100 μm) due to poor dispersion. Organosilicon liquids markedly improve hydrophobicity of MKG, with water transport inhibition varying based on the functional groups of organosilicons and the microstructure of MKG matrix. This work reveals the effects and underlying mechanisms of various organic liquids on the reaction and properties of MKG, providing guidance for assessing their engineering applicability, durability, and functionality, and promoting the full utilisation of available resources.
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
APPLIED CLAY SCIENCE
·
2014
·
IF 2.703
Lu Zeng,Dan-yang Cao,Yan Xu,Chun-wei Fan,Xiao-qin Peng
This paper introduces a novel method for the preparation of a geopolymer using kaolinite intercalation compound which is calcined at a low temperature and forms a geopolymer by alkaline activation . The samples were characterized by X-ray diffraction (XRD), Thermogravimetric/Differential scanning calorimetry (TG/DSC) and Fourier transformed infrared spectroscopy (FTIR). Coal-bearing strata kaolin (CSK) mainly consisting of kaolinite and quartz was used to prepare the intercalation compound (CSK-K) with potassium acetate (KAc) and calcined below 400 °C. The calcination temperature and the dosage of KAc were analyzed. The results showed that CSK calcined below 400 °C cannot be alkali-activated to harden and when the dosage of KAc was 30% by mass of CSK, CSK-K calcined between 350 °C and 400 °C can be alkali-activated to form the geopolymer with a high compressive strength around 31 MPa. This was attributed to the formation of metakaolin and geopolymerization which were related to the effect of intercalation reaction and the content of K + . CSK-K calcined at low temperature has great potential as a novel material for the manufacture of geopolymers.
研究领域:
材料科学
·
地质学
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2022
·
IF 5.518
Haize Jin,Yuhang Zhang,Xingxing Zhang,Min Chang,Cuixia Li,Xuefeng Lu,Qikun Wang
Geopolymers have high application potential due to their outstanding ion exchange ability. A novel direct ink writing (DIW) geopolymer adsorption sieve (GAS) preparation strategy was proposed. The preparation and optimization of DIW inks and the adsorption properties and mechanism of GAS for methylene blue (MB) were systematically investigated by characterization and density functional theory (DFT) calculation. The GASs exhibited desired adsorption rates for MB in both dynamic (83.6% at 200 min) and static (97.1% in 7 days) states. The adsorption kinetic was fitted well by the pseudo-first-order model at the early stage and eventually was transformed to fit well by the pseudo-second-order model and indicated the boundary liquid layer diffusion and intraparticle diffusion were all rate-limiting factors. The exploration of adsorption mechanism confirmed that the adsorption of GAS for MB was affected by the coordination of electrostatic action, hydrogen bonds and electrons transfer . The proposed strategy provides a promising reference for design and preparation of eco-friendly 3D printing adsorbent systems.
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
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Yi Fang,Lang Yang,Feng Rao,Yongming Zheng,Zhenguo Song
In this study, a low-cost porous geopolymers (PGP) were prepared using coal gangue and fly ash as raw materials to remove organic and heavy metal ions from wastewater. Various characterization techniques were employed to investigate the microstructure, morphology, pore size distribution, and surface functional groups of the porous geopolymers. The results indicate that the geopolymer exhibits a porous structure with hydroxyl groups on the surface after foaming. It was found that the porous geopolymers exhibited good adsorption capacity for Methylene Blue (MB), Cu(II), and Pb(II), with optimal adsorption capacities reaching 35.60 mg/g, 98.31 mg/g, and 85.67 mg/g, respectively. Fitting analysis suggests that the adsorption of MB, Cu(II), and Pb(II) is better described by the pseudo-second-order kinetic model and the Freundlich isotherm model. This indicates that the adsorption process is primarily chemical adsorption with multilayer adsorption. Competitive adsorption studies showed that Cu(II) could enhance the adsorption of MB, while Pb(II) had no significant effect on the adsorption of MB. Mechanistic studies revealed that the adsorption of MB by PGP is mainly through pore adsorption, electrostatic attraction, and hydrogen bond formation; whereas the adsorption of Cu(II) and Pb(II) is primarily through pore adsorption, electrostatic attraction, chemical reactions, and ion exchange. Recycling experiments demonstrated that after five repetitions, the adsorption capacity of PGP for the three pollutants remained above 60 %. These findings confirm the potential of porous geopolymers as adsorbents. Preliminary cost analysis shows that the adsorption cost of porous geopolymers is only 2.07 RMB/kg, making the geopolymer adsorbent economically advantageous and promising for application, especially considering its ability to utilize industrial solid waste.
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
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·
IF 5.8
Zixu Chen,Peigang He,Wanlin Li,Shengjian Zhao,Dechang Jia,Paolo Colombo,Yu Zhou
Geopolymers with zeolite-like structures can effectively immobilize radioactive ions through their three-dimensional cage-like framework. This study investigated the synthesis of geopolymers via cold reaction sintering using metakaolin, anhydrous and nonahydrate sodium metasilicate for Cs + immobilization. Optimizing the Si/Al molar ratio to 1.5:1 and water content to 20 wt% yielded the best mechanical properties and near-complete reaction. The transient liquid phase formed by the dehydration of sodium metasilicate nonahydrate facilitated densification. CsCl incorporation resulted in a predominantly amorphous phase with the formation of NaCl crystals. Toxicity leaching tests demonstrated Cs + immobilization rate exceeding 91 % for CsCl content below 12 wt%. Short-term leaching tests confirmed low leaching rates (< 4 × 10⁻³ cm/day after 4 days), and leachability indices well above the typically required value of 6 for cement-based matrices. These results establish the viability of cold reaction sintered geopolymers for Cs + immobilization, highlighting their promise for nuclear waste management applications.
研究领域:
材料科学
·
核废物管理
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL POLLUTION
·
2021
·
IF 8.071
Qiushi Zhang,Xing Cao,Shichang Sun,Weichen Yang,Lin Fang,Rui Ma,Chenghua Lin,Haowen Li
Lead-zinc slag (LZS) is a solid waste product that is rich in silicon and aluminum and has enormous resource potential for functional environmental functional geopolymer materials. Unfortunately, the solidification mechanism of heavy metals in geopolymers is still unclear, which is detrimental to the heavy metal solidification of LZS. In this study, we comprehensively studied and demonstrated the solidification mechanisms of Pb and Zn in geopolymers, based on the preparation of high-performance LZS-based geopolymers (compressive strength up to 89.3 MPa, and Pb and Zn solidification efficiency up to 93.1% and 90.0%, respectively). Thereafter, the solidification mechanism differences between Pb and Zn were explained by electronegativity and ion potential. Due to the ionic potential order of Zn 2+ > Pb 2+ > Na + , both Zn 2+ and Pb 2+ could exchange with Na + in the geopolymer. In addition, due to the electronegativity order of Pb > Si > Zn, Pb could attack the [SiO 4 ] structure and form covalent bonds in the Pb–O structure, while Zn did not (shown by Raman spectroscopy). As a result, Pb simultaneously solidified in the geopolymer through covalent bonding and ion exchange, while Zn was solidified mainly by ion exchange. Thus, this work provides new perspectives and ideas for the solidification mechanisms of heavy metals in geopolymers.
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
危险品化学品经营许可证（带存储）