APPLIED SURFACE SCIENCE
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2017
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IF 3.387
Tao Yang,Enlin Han,Xiaodong Wang,Dezhen Wu
A new methodology to decorate the surface of polyimide (PI) fiber with carbon nanotubes (CNTs) has been developed in this study. This surface decoration was carried out through a surface alkali treatment, a carboxylation modification, surface functionalization with acyl chloride groups and then with amino groups, and a surface graft of CNTs onto PI fiber. Fourier -transform infrared and X –ray photoelectron spectroscopic characterizations confirmed that CNTs were chemically grafted onto the surface of PI fiber, and scanning electron microscopic observation demonstrated the fiber surface was uniformly and densely covered with CNTs. The surface energy and wettability of PI fiber were improved in the presence of CNTs on the fiber surface, which made a contribution to enhance the interfacial adhesion of PI fiber with other inorganic matrices when used as a reinforcing fiber. The application of CNTs-decorated PI fiber for the reinforcement of phosphoric acid-based geopolymers was investigated, and the results indicated that the geopolymeric composites gained a noticeable reinforcement. Compared to unreinforced geopolymer, the geopolymeric composites achieved a remarkable increase in compressive strength by 120% and in flexural strength by 283%. Fractography investigation demonstrated that the interaction adhesion between the fibers and matrix was enhanced due to the surface decoration of PI fiber with CNTs, which contributed to an improvement in fracture-energy dissipation by fiber pullout and fiber debonding from the matrix. As a result, a significant reinforcement effect on geopolymeric composites was achieved through a fiber-bridging mechanism. This study provided an effective methodology to improve the interracial bonding force for PI fiber and also proves a highly efficient application of CNTs-decorated PI fiber for the mechanical enhancement of geopolymeric composites.
研究领域:
材料科学
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复合材料
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纳米技术
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地质聚合物科学
✓ 已验证
产品关联
DOI
高影响因子
Waste and Biomass Valorization
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2024
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IF 2.6
Wang Jiahe,Lu Jinshan,Wang Hongzhi
The reutilization of marble sludge from the marble cutting and polishing process offers economic and environmental benefits. In this work, fly ash is used as an aluminosilicate source to prepare geopolymers with marble sludge. The crystal composition, gel structure, pore distribution, microstructure and Na + ion leaching behavior were investigated to determine the effects of multiscale fillers on the apparent density, compressive strength, and efflorescence performance of the geopolymers. The addition of graphene oxide (GO) filler catalytically promotes geopolymerization reactions, inhibits microcrack formation and increases the compressive strength, albeit with pronounced efflorescence. In contrast, the hydrophobic SiO 2 aerogel (SA) filler effectively eliminates the pores and hinders water permeability and Na + leaching, thus greatly improving the anti-efflorescence properties. The concentration of Na + ions in the leach solution follows an exponential relationship with leach time, indicating diffusion controlled leaching behavior. With the combination of 1‰ GO and 1% SA, the geopolymer achieves a compressive strength of 40.6 MPa and a surface contact angle of 99.1°. After the immersion efflorescence test, the geopolymer shows a mass loss of 4.3% and a strength loss of 7.2%, far superior to those of the unfilled geopolymer. The strengthening and improved anti-efflorescence properties are closely related to the densification and increased hydrophobicity of the geopolymers. The synergistic effect of different fillers provides a simple technical route to produce high strength and anti-efflorescence geopolymers with marble sludge, promising suitability for applications in paving and embankment blocks. Graphical Abstract
研究领域:
材料科学
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环境工程
✓ 已验证
产品关联
DOI
高影响因子
CEMENT & CONCRETE COMPOSITES
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2017
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IF 4.265
Xiaolu Guo,Huisheng Shi,Xue Wei
In order to study the influence of waste brick powder (WBP) and nano-modification on class C fly ash (CFA) based geopolymer , pore properties (i.e. bulk density, apparent porosity , and true porosity, and closed porosity) were tested according to the related Chinese National Standard, and the pore structure was also explored by mercury intrusion porosimetry (MIP); Water leaching procedure were performed to study the inner chemical environment; X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS) were measured to the microstructure and modification mechanism. The results show that WBP as additive results in a denser structure of geopolymer; nano-modification improves the pore structure, ameliorates the anti-leaching ability of geopolymer by constraining the soluble ions in gels, makes the geopolymerization more complete, and results in a denser paste structure by filling gaps between the particles with amounts of reaction products.
✓ 已验证
DOI
高影响因子
WASTE MANAGEMENT
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2025
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IF 7.1
Ke Li,Jie Deng,Ying Zhu,Weiyi Zhang,Tao Zhang,Chao Tian,Jinwei Ma,Yingying Shao,Yanfeng Yang,Yanqiu Shao
Municipal solid waste incineration fly ash (MSWIFA) is considered a hazardous solid waste, traditionally disposed by solidified landfill methods. However, solidified landfills present challenges with leaching heavy metals, polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). To address this issue, this study examined two pretreatment methods for MSWIFA: sintering at 850℃ for 30 min and washing with three water baths (20 min each) at a 3:1 liquid–solid ratio. Then, the pretreated MSWIFA was employed in geopolymer synthesis, along with gold tailings (GT) and coal fly ash (CFA). The optimal raw material ratio was GT:CFA:MSWIFA = 5:4:1 after pretreatment, which resulted in maximum compressive strengths of 20.95 and 25.87 MPa for the sintered and washed samples, respectively. Washing removed 87.3 % of soluble chlorides from MSWIFA, enhancing the compressive strength of the geopolymer. High-temperature treatment effectively reduced the leaching concentrations of heavy metals and the toxic equivalent quantity (TEQ) of PCDD/Fs. The leaching concentrations of heavy metals (Cu, Zn, Cd, Pb) and the TEQ of PCDD/Fs were all below the limits established by Chinese standards GB 5085.3–2007 and HJ 1134–2020. X-ray Diffraction, Fourier transform infrared spectrometry, scanning electron microscopy, and energy dispersive spectroscopy analyses revealed that the primary hydration products of the geopolymer are C–(A)–S–H gels. Washing treatment facilitated the formation of ettringite and Ca(OH) 2 , which enhanced the pore structure and optimized the performance of the geopolymer. Thermogravimetric analysis revealed the good thermal stability of the geopolymer, indicating that the high-temperature and washing pretreatments minimally impacted its thermal stability.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
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2024
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IF 7.4
Haize Jin,Chenxi Qiu,Yansong Li,Junyi Liu,Dabo Zhang,Qiao Chen,Xuefeng Lu,Cuixia Li,Qikun Wang
The crux to practical application of geopolymer adsorbents for antibiotics that are easily protonated and deprotonated is to clarify the dynamic adsorption mechanism of geopolymer with intrinsic alkaline release. The adsorption properties, adsorption mechanism, adsorption-desorption cycle and waste adsorbent regeneration based on the geopolymer adsorbent for adsorbing tetracycline under the spontaneous dynamic pH conditions were systematically investigated by experiment, characterization and density functional theory. The results confirmed that the structures of tetracycline depended on dynamic pHs of adsorption systems changed by geopolymer adsorbent. The electrostatic interaction assisted by hydrogen-bonding and n-π interaction dominated the adsorption process when the dynamic pHs were less than 7. And the hydrogen-bonding and n-π interaction provided the possibility of weak adsorption effect in highly alkaline environments. The geopolymer powder exhibited outstanding adsorption efficiency (∼95.62%, 30 min) due to the strong electrostatic adsorption between electronegative skeleton of geopolymer and zwitterions species tetracycline under dynamic pH range of 4–6.3 and fitted the pseudo-second-order model. The outstanding competitive adsorption properties in NaCl solution, adsorption (4 times)-desorption (3 times) cycle properties and regenerative property of waste adsorbent were exhibited. The mechanism study based on the dynamic pHs which is closer to actual conditions can provide important reference for practical application of easy preparation and low cost geopolymer adsorbents.
研究领域:
环境科学
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材料科学
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化学工程
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分析化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）