JOURNAL OF ENVIRONMENTAL MANAGEMENT
·
2024
·
IF 8
Shengjian Zhao,Hualong Yang,Xuehui Liu,Siqi Ma,Peigang He,Zhenlin Sun,Dechang Jia,Paolo Colombo,Yu Zhou
Metakaolin-based geopolymers are very promising materials for improving the safety of low and intermediate level radioactive waste disposal, with respect to ordinary Portland cement , due to their excellent immobilization performance for Cs + and superior chemical stability. However, their application is limited by the fact that the leaching behavior of Cs + is susceptible to the presence of other ions in the environment. Here, we propose a way to modify a geopolymer using perfluorodecyltriethoxysilane (PDFS), successfully reducing the leaching rate of Cs + in the presence of multiple competitive cations due to blocking the diffusion of water. The leachability index of the modified samples in deionized water and highly concentrated saline water reached 11.0 and 8.0, respectively. The reaction mechanism between PDFS and geopolymers was systematically investigated by characterizing the microstructure and chemical bonding of the material. This work provides a facile and successful approach to improve the immobilization of Cs ions by geopolymers in real complex environments, and it could be extended to further improve the reliability of geopolymers used in a range of applications.
研究领域:
材料科学
·
放射性废物管理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Cleaner Production
·
2025
·
IF 10
Jialin Chen,Jingfei Zhou,Shoukai Chen,Haibo Shi,Qingfeng Hu,Yingdong Tang
It is anticipated that this would address the underlying reasons of the disposal challenges and associated safety hazards if Cr-containing tannery waste from the tannery industry could be produced into stabilized sustainable construction materials. In this paper, the geopolymer was prepared employing solid waste furnace slag (FS) and tannery sludge powder (TSP) and evaluated for mass loss rate, appearance, residual compressive strength, pore properties, phase transformation and Cr leaching behavior after different thermal exposure (200 °C, 400 °C, 600 °C, 800 °C, and 1000 °C) for 2 h. The results revealed that the compressive strength increased and then dropped with increasing thermal exposure temperature, with the residual compressive strength of geopolymer being the maximum (63.00 MPa) at 200 °C. Dehydroxylation and phase transition disrupted the pore structure, and the hydration products, mostly C-(A)-S-H, underwent depolymerization and repolymerization to create new crystalline phases including akermanite and gehlenite. Even at 600 °C, which has the greatest impact on the safety of geopolymers, the leaching concentrations of total Cr and Cr (Ⅵ) were only 1.39 mg/L and 0.074 mg/L, respectively, which were still far below the standard requirements. The possible Stabilization-Migration-Restabilization (SMR) route of Cr was identified as follows: Cr was physically encapsulated by C-(A)-S-H at 20 °C–400 °C; C-(A)-S-H was destroyed at 600 °C–800 °C, and Cr migrated and was oxidized to Cr (Ⅵ) by CaO; it was then probably reduced to Cr(V) by heat and Mg-O at 1000 °C and finally immobilized in akermanite by chemical bonding.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2023
·
IF 7.4
Xiaohui Sun,Ziyi Chen,Keyu Guo,Jianbo Fei,Zijun Dong,Hao Xiong
Geopolymeric flocculation-solidification of the tail slurry of shield tunnelling spoil after sand separation was investigated to replace the low-efficient flocculation and filter-pressing method currently adopted on site. The geopolymeric flocculation-solidification agent (GBFS-FS) consisting of flocculation component and geopolymeric solidification component (granulated blast-furnace slag (GBFS) activated by alkali) was prepared and investigated through flocculation-sedimentation test, dewatering model test, unconfined compression test, SEM test, etc. In the flocculation-sedimentation test, the GBFS-FS agent demonstrated the best flocculation effect as compared with other cementitious flocculation-solidification agents. The dewatering model tests revealed that adding the GBFS-FS agent into the slurry can not only dewater the slurry efficiently, but also generate solidified clayey sediments with quickly-increased strength. The solidified clayey sediments with GBFS-FS showed strengths 3.5 times higher than others with cementitious agents at a 28-day curing age. The GBFS-FS agent can also facilitate to make controlled low-strength material (CLSM) using the tail slurry. The fluidity and strength of CLSM with GBFS-FS were distinctly better than those of other groups. SEM test shows that the components of the GBFS-FS agent can interact to avoid large flocs and support each other in strength growth.
研究领域:
土木工程
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2025
·
IF 8
Xingyi Zhu,Muhammad Kashif Anwar,Guomin Deng,Xiaoming Wang,Jiakang Wang,Yating Zhang,Junming Su,Zedong Qu,Francisco A. Gilabert
This study investigates the novel application of microwave heating to optimize the rheology, interlayer bond, and buildability of 3D-printed geopolymers at various printing stages. Unlike conventional methods, microwave heating significantly enhances stacking performance (buildability) while reducing flowability, addressing critical challenges in 3D printing. The findings also indicate that deformation resistance coefficients for fiber-free and fiber-reinforced geopolymers reaches 0.933–1.00 after 30 and 45 seconds of microwave exposure, respectively, demonstrating superior shape retention ability after microwave heating. Notably, microwave heating improves ultra-early (i.e., 2 h and 4 h) interfacial strength proportionally to power and duration, offering a breakthrough for rapid construction. In addition, drying shrinkage decreases by 0.096–0.226 % (fiber-free), 0.054–0.166 % (PE fiber), and 0.067–0.17 % (steel fiber), highlighting the efficacy of microwave heating in mitigating cracking of 3D-printed geopolymers. The optimized microwave processing parameters establish in this study serve as a foundation for in-line, large-scale 3D printing applications, offering a scalable solution in printability and structural integrity.
研究领域:
土木工程
·
材料科学
✓ 已验证
DOI
高影响因子
CEMENT & CONCRETE COMPOSITES
·
2024
·
IF 10.8
Ningning Shao,Chunling Dong,Xuankun Wei,Yiping Su,Zhijun Dong,Zuotai Zhang
Pore structure control mechanism in geopolymer foams (GPFs) remains qualitatively understood, posing great challenges for GPF applications. In this study, by modelling of various pore structures with regular geometric patterns, total porosity, open porosity, pore size distribution , and pore deformation were quantitatively characterized. Then, we focused on slurry viscosity and surface tension as the two crucial parameters, and investigated their impacts on the evolution of pore structures. It was revealed that viscosity primarily influenced foam deformation and coalescence, ultimately affecting foaming height, sample appearance, and the occurrence of foam collapse. Slurry surface tension predominantly affected pores connectivity, low surface tension corresponded to highly interconnected pores, while higher values favored closed pores. Additionally, a simple prediction model that enables the estimation of pore structures and their distributions based on GPFs visual appearance and height was proposed. At last, the relationships between pore structure and macro-performance were analyzed.
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
Journal of Cleaner Production
·
2024
·
IF 9.7
Jiang-shan Li,Wei Zhang,Lei Lang,Chen-xi Dong,Kang Huang
The environmental pollution resulted from the stacking of solid wastes, and the 250 kg CO 2 emission caused by calcined a ton of kaolinite have become an urgent problem to be solved. In this study, a novel phosphoric acid-activated geopolymer was developed, which was composed of fly ash (FA), mechanically activated-kaolinite (MAK). The influences of phosphoric acid concentration, mechanical grinding duration, and curing temperature were investigated. Microstructural properties of FAMAK geopolymers were examined through a serious of tests. Furthermore, the Gibbs free energy and nano-scale structure characteristics of acid-activated hydration products were calculated for the first time by using density functional theory . The results show that the optimal mass ratio of FA to MAK is 7:3 with 8 mol/L phosphoric acid, which led to the maximum compressive strength of 36.6 MPa at 56-day. Besides, the optimal grinding time is 3 h and temperature is 40 °C. Moreover, the content of silicon promotes the polymerization reaction. The valence and bonding of aluminum are primarily affected by its coordination number. The key outcomes in this study provides a low-carbon cementitious materials, which can achieve the double benefits of carbon reduction and the utilization of solid wastes.
研究领域:
材料科学
·
环境科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2014
·
IF 2.265
Xiaolu Guo,Wenpei Hu,Huisheng Shi
Nano-modified composite geopolymers were successfully prepared from municipal solid waste incineration fly ash (MSWIFA) and class C fly ash (CFA). The results indicate that both nano-SiO 2 and nano-γ-Al 2 O 3 have a good modification effect on geopolymer, of which nano-SiO 2 has a better performance than nano-γ-Al 2 O 3 . The optimum content of nano-SiO 2 and nano-γ-Al 2 O 3 are 1.5% and 2.0%, respectively. XRD shows that there is no new phase emerging after adding a small amount of nanomaterials. By FT-IR and SEM, it means that nanomaterials facilitate the reaction of geopolymer, making the modified geopolymer more compact. BET shows nano-SiO 2 especially modifies the pore distribution and pore structure of geopolymers. Additionally, nanomaterials have an improvement to the solidification/stabilization (S/S) of heavy metals.
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
ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
·
2021
·
IF 6.291
Tao Huang,Lulu Zhou,Zhenxing Cao,Shuwen Zhang,Longfei Liu
A microwave (MA) irradiation-persulfate-formate system was constructed to detoxify Cr contamination and solidify the geopolymerization of the alkali-activated composite material. Three series of experiments were correspondingly conducted to evaluate the treatment for the chromate-contaminated soil. The changes in the molar ratios of formate to persulfate and the mass rates of fortifier to soil led to a significantly greater reduction of Cr VI in the detoxification experiments. The increase of blast furnace slag from 50% to 80% in the composite cementitious materials (CCM) intensified the immobilization efficiencies of chromate and the compressive strengths of geopolymer blocks. MA irradiation potentially enhanced the binding of Ca cations to the aluminosilicate compounds. The degree of reaction in the phenomenological kinetics model mathematically verified the geopolymerization process. Ettringite was formed within the structure of the geopolymer in the coupling system. Sulfate radicals released from persulfate not only contributed to the detoxification process but also strengthened the immobilization process.
研究领域:
环境科学
·
土壤修复
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
International Journal of Applied Ceramic Technology
·
2023
·Vol. 20
·期 5
·3246-3256
·
IF 2.1
Qian Meng,Yao Jun Zhang,Pan Yang He,Hao Chen,Chan Juan Li
The photoelectrocatalysis is an efficient and sustainable degradation method for organic contaminant, where the photoanode material plays a critical role. Development of novel, inexpensive, and high-performance photoanode materials is significant to enhance the degradation performance of anodes catalysis. Herein, a novel carbon-fiber geopolymer composite-coated electrode with low cost and facile production was prepared by incorporating carbon fibers in a geopolymer matrix. The as-developed photoelectrocatalyst coupled with persulfate could effectively degrade more than 98 % of rhodamine B within 6 min, which demonstrated superior catalytic activity compared with various catalysts reported in the literature. Moreover, the composite electrodes exhibited excellent reusability. The endogenous Fe 2 O 3 and TiO 2 in the geopolymer matrix were the main active materials, providing photoelectron-hole pairs for dye molecule degradation. Significantly, the carbon fibers in the matrix effectively connected the scattered oxide species and prompted the separation and migration of photoinduced carriers while enhancing the stability of the catalysts and improving the conductivity of the matrix. When the carbon content was increased from 0 to 6 wt%, the conductivity of the composite increased by 17.75 times. This study offers a cost-effective and eco-friendly photoelectrocatalyst, which shows significant potential for further development.
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
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Haize Jin,Kaiqiang Hong,Junyi Liu,Chenxi Qiu,Mengyao Zhu,Cuixia Li,Qikun Wang
A powder, inorganic membrane and 3D printing cetyltrimethylammonium bromide (CTAB)-geopolymer adsorbents system for adsorbing tetracycline (TC) was developed. And the adsorption properties, adsorption mechanism, adsorption cycle application based on the dynamic pH of adsorption system were systematically investigated by experiment, characterization and density functional theory (DFT) calculation. The introduction of CTAB significantly increased the adsorption response to TC in the high alkaline environment caused by spontaneous alkali release of geopolymer. The adsorption of CTAB-geopolymer for TC was most efficient in the dynamic pH range corresponding to TC - species. The predominant influencing mechanism between CTAB-geopolymer with TC was electrostatic interaction assisted by the hydrogen bonding and n-π interaction. The powder adsorbent with 11 wt% CTAB can capture 92.38 % TC at 2 min and fitted the pseudo-second-order model, and was also suitable for adsorption of trace TC. Although the extension of the diffusion path of the monolithic adsorbents limited the adsorption rate, the 3D printed adsorbent showed an adsorption efficiency of 84.20 % at 302 min. The outstanding adsorption (4 times)-desorption (3 times) cycle properties of 11 %CT-GA (81.15 % at 24 min, 4th adsorption) and cycle cumulative adsorption efficiency of 11 %CT-3DP (59.23 % at 120 min, 4th adsorption) adsorbent were exhibited. Furthermore, a high accuracy performance prediction model with the mean R 2 value tended to 1 and the low root mean square error (0.0747) was provided, which can provide theoretical and technical reference for the subsequent industrial application of CTAB-geopolymer adsorbents.
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
CONSTRUCTION AND BUILDING MATERIALS
·
2023
·
IF 7.4
Gonghui Gu,Yaowen Pei,Tao Ma,Feng Chen,Jinglin Zhang,Fang Xu
Carbon fiber-reinforced geopolymer composite (CFGC) can be used as the energy conversion layer of airport pavement, thus converting electromagnetic energy into heat energy via induction heating technology to melt snow and ice on pavement surface. In this study, fly ash (FA), granulated blast furnace slag (GBFS) and carbon fibers were used to prepare carbon fiber-reinforced FA-GBFS geopolymer composite (CFFGC). Then, the modification mechanism of carbon fibers on the electrothermal and mechanical properties of CFFGC was studied, in which important effects arising from the geopolymerization process within CFFGC were focused on. Results show that the gullies on carbon fiber surface can provide nucleation sites for the geopolymerization and calcium silicate hydration reaction in CFFGC, which accelerates the precipitation of reactive Si(OH) 4 and [Al(OH) 4 ] - in the raw materials and promotes the generation of geopolymer gels and C S H gels, thus enhancing the mechanical performance of CFFGC. In addition, when the carbon fiber dosage reaches 0.4 wt%, a substantial conductive network is formed inside CFFGC, which shortens the conductive path and greatly improves the charge transfer capability in CFFGC. Once the carbon fiber dosage exceeds 0.4 wt%, the agglomerated carbon fibers within CFFGC can intensify the phonon scattering, thus reducing its thermal conductivity.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ENVIRONMENTAL MANAGEMENT
·
2022
·
IF 8.91
Xuankun Wei,Feng Xie,Chunling Dong,Pengju Wang,Jiyun Xu,Feng Yan,Zuotai Zhang
Hazardous waste incineration fly ash (HFA) is considered a hazardous waste owing to the high associated concentrations of heavy metals and soluble salts . Hence, cost effective methods are urgently needed to properly dispose HFA. In this study, geopolymers were prepared by alkali-activation technology to stabilize and solidify heavy metals in HFA. In addition, the effects of three different aluminosilicates (metakaolin, fly ash, and glass powder) on the heavy metal immobilization efficiency were investigated. Because the soluble salt content of HFA is too high for their direct placement in flexible landfill sites and water washing can lead to heavy metal leaching, water-washing experiments were conducted after alkali-activation treatment to remove soluble salts. The results suggest that the concentrations of heavy metals leached from geopolymers can satisfy the Chinese Standard limits (GB18598-2019) when the addition of aluminosilicates exceeds 20 wt%. More than 77% of Cl − and >64% of SO 4 2− in geopolymers could be removed via water-washing treatment. The Zn leaching concentration was maintained below approximately 0.52 ppm. After alkali-activation treatment, the water-washing process could efficiently remove soluble salts while inhibiting heavy metal leaching. Sodium-aluminosilicate-hydrate (N-A-S-H) gel, a product of the geopolymerization process in this study, was demonstrated to act as a protective shell that inhibited heavy metal leaching. Hence, HFA-based geopolymers are considered suitable for disposal in flexible landfills.
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）