Journal of Water Process Engineering
·
2024
·
IF 6.3
Liang He,Yanfei Liu,Huajing Zhou,Sheng Liang,Xiaolong Zhang,Zuwen Li,Zilian Liu,Rongrong Miao,Qingqing Guan
Targeted tuning of defect density in carbon-based photocatalysts is a key strategy to improve their photocatalytic performance. However, the current methods for intrinsic carbon defect sites construction are commonly with harsh conditions and costly materials, it is significant to develop more greener and cost-effective methods. In addition, the structure-activity relationship between the structural defects of material and photocatalytic performance was ambiguous up to now. Herein, a K + -assisted synthetic strategy was developed to synthesize porous carbon-based geopolymer micros (rpsBC-GPs 2 ) with abundant intrinsic defects using papermaking sludge as the precursor. And a mechanistic insight was given for explaining why the K + -induced defect density tuning made rpsBC-GPs 2 exhibit high photocatalytic activity . The introduction of K + changed the crystal structure of Quartz, calcite and pyrrhotite on the catalyst surface and promote the generation of lattice defects . The abundant lattice defects and sp 3 carbon defects of rpsBC-GPs 2 were evidenced with X-ray Photoelectron Spectroscopy, X-ray Diffraction, and scanning transmission electron microscopy measurements. In the photocatalytic process, the photogenerated electrons was driven to capture dissolved oxygen and form ·O 2, because the conduction position of rpsBC-GPs 2 was higher than the potential of O 2 /O 2 − (−0.33 eV). In addition, the high-conductive biochar play a role of “electron shuttle” in the photocatalytic process, which promoted the electrons transfer from CB to O 2 . Therefore, the production efficiency of reactive ·O 2 − was improved, and promoted the aromatization reaction process of tetracycline (TC). In this study, an industrial waste paper sludge was utilized to synthesize the active photocatalyst, and a new strategy was proposed for the photocatalytic performance evaluation, through targeted tuning of defect density in carbon-based photocatalysts using K + as activator.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
ENVIRONMENTAL RESEARCH
·
2025
·
IF 7.7
Xiuqiong Fu,Qian Wan,Yong Fan,Yimin Zhang,Ruobing Zhang,Zhijie Guo
The preparation of geopolymers from tailings rich in quartz typically requires activation to enhance final strength, though the underlying mechanism remains unclear. Quartz, as a common inert gangue mineral in tailings, was selected as the research subject. Quartz with varying reactivity was prepared through mechanical activation of different particle sizes and used for geopolymer synthesis, aiming to elucidate the strengthening mechanism of activated quartz on geopolymers. When the activation time was identical, quartz particles of different sizes exhibited the same soluble silicon content. However, due to the increased surface-active groups after activation, geopolymers derived from larger quartz particles (5–8 mm) achieved compressive strengths of 57.24–64.73 MPa, while those from smaller particles (0.08–0.12 mm) only reached 43.83–50.42 MPa. After activation, the main active groups on the quartz surface were the Q n (n = 1, 2, 3) structures containing non-bridging oxygens and silicon radicals. The Q 1 and Q 2 structures mainly provide soluble silicon in geopolymerization and have little effect on the strength of the geopolymer. While the Q 3 structure can combine with the geopolymer gel through Si-O-Si bonds, reducing the porosity at the interface between quartz and geopolymer, significantly enhancing the strength of geopolymer. The results indicate that, compared to soluble silicon content of quartz, the content of active groups on its surface is the main factor influencing the performance of geopolymer. For the activation of tailings, increasing the reactivity of their surface is more effective in improving geopolymer strength than enhancing the leaching of soluble silicon and aluminum through overall activation.
研究领域:
材料科学
·
土木工程
·
矿物加工
·
表面化学
·
聚合物科学
✓ 已验证
产品关联
DOI
PubMed
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
·
环境科学
✓ 已验证
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 39
·18839-18847
·
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
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
·
土木工程
✓ 已验证
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
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
Materials
·
2024
·Vol. 17
·期 6
·1431
·
IF 3.1
Bao Mi,Hui Zhao,Meng Lu,Yi Zhou,Yongjie Xue
The massive stockpiling of electrolytic manganese residue (EMR) has caused serious environmental pollution. In this study, EMR, coal gangue (CG), and fly ash (FA) were used as raw materials to obtain the optimal mix ratio based on Design-Expert mixture design. The effects of activator modulus, liquid–solid (L/S) ratio, and curing temperature on the mechanical properties of geopolymers were investigated. The results showed that the compressive strength of the prepared geopolymer was 12.0 MPa, and the 28d leaching of Mn was 0.123 mg/L under the conditions of EMR:CG:FA = 0.43:0.34:0.23, L/S = 0.9, a curing temperature of 60 °C, and a curing time of 24 h. This indicates that the geopolymer is an environmentally friendly material with high compressive strength. The mineral composition of the geopolymer is mainly hydrated calcium silicate and geopolymer gel. In addition, a more stable new mineral phase, MnSiO3, was generated. The Fourier transform infrared (FTIR) spectrogram showed that the peak at 1100 m−1was shifted to 1112 cm−1, which indicated that a geopolymerization reaction had occurred. Through scanning electron microscopy (SEM) and energy dispersive spectrum (EDS) analysis, it was identified that the geopolymerization produced a large amount of amorphous gelatinous substances with a relatively dense structure, the major elements being oxygen, silicon, aluminum, calcium, and sodium.
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 Physical Chemistry C
·
2023
·
IF 3.7
Xuankun Wei,Yongqi Sun,Yiping Su,Xuehua Shen,Yuanyuan Tang,Feng Yan,Zuotai Zhang
Geopolymers have emerged as a promising solution for solidifying heavy metals; however, the underlying mechanisms remain elusive. In this study, we synthesized geopolymers incorporating Pb2+ and Cd2+ to unravel their solidification mechanisms. Leaching analyses demonstrated superior solidification efficacy for Pb2+ (93.6%) compared to that for Cd2+ (65.2%). The dissimilarity in solidification mechanisms can be attributed to variances in ionic potential and covalent interactions between the cations. Furthermore, Cd2+ exhibited a higher ionic potential, facilitating its exchange with Na+ in the geopolymer matrix. Triple-quantum nuclear magnetic resonance experiments revealed a weak affinity of the geopolymer structure toward Cd2+. Density functional theory calculations affirmed stronger interactions between Pb2+ (−8.71 eV) and the matrix compared to those of Cd2+ (−5.83 eV). Consequently, Pb2+ demonstrated an enhanced covalent propensity within the geopolymer matrix, while Cd2+ primarily underwent solidification via ion exchange. This research provides novel insights and concepts regarding the mechanisms involved in solidifying heavy metals in geopolymers.
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
CONSTRUCTION AND BUILDING MATERIALS
·
2025
·
IF 8
Chao Kang,Mengyao Sun,Ning Wang,Chenlong Duan,Shengchao Yang,Sheng Dong,Yuqian Zhao,Yundong Yang,Tao Yang,Jinpeng Qiao
To achieve low-cost and environmentally friendly utilization of coal gangue, this study systematically investigates the mechanical properties and microstructural evolution of geopolymers prepared by co-utilizing raw coal gangue (RCG) and calcined coal gangue (CCG). The results show that with increasing RCG incorporation, the compressive strength and workability of the geopolymers gradually decrease, whereas the setting time is significantly prolonged. Thermodynamic and microstructural analyses reveal that kaolinite is nearly inert in the geopolymerization process and mainly acts as a filler, whereas metakaolinite serves as the primary reactive phase. When the RCG replacement ratio is 40 %, the 28-day compressive strength of the geopolymer reaches 21.81 MPa, exceeding the requirements for road base materials. Meanwhile, the initial setting time is extended from 150 min to 400 min, indicating a remarkable regulating effect of RCG on the setting behavior. Furthermore, compared with the geopolymer prepared solely from CCG, incorporating 40 % RCG reduces carbon emissions by 103.7 kg CO 2 -equivalent per ton of geopolymer, corresponding to a 29.39 % decrease, while the production cost is reduced by approximately 9.62 %. This study demonstrates the feasibility of co-utilizing raw and calcined coal gangue to produce high-performance geopolymers and provides a sustainable approach for large-scale coal gangue resource utilization.
研究领域:
材料科学
·
土木工程
·
环境科学
·
废弃物利用
·
可持续建筑材料
✓ 已验证
产品关联
DOI
高影响因子
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
APPLIED CLAY SCIENCE
·
2026
·
IF 5.8
Xiuqiong Fu,Qian Wan,Yong Fan,Yimin Zhang,Ruobing Zhang
Temperature has an important influence on geopolymerization. While existing studies have mainly focused on curing temperature effects, research on the influence of mixing temperature remains limited. This study investigated the effects of mixing temperature between alkali activators and metakaolin (MK) on the physical properties, microstructure, and reaction kinetics of metakaolin-based geopolymers (MKGs). The results demonstrated that different mixing temperatures led to distinct geopolymerization processes and had significant impacts on mechanical performance. With increasing mixing temperature, compressive strength first increased and then decreased. Geopolymers prepared at 50 °C (MKG50) exhibited a denser structure and the highest compressive strength, reaching 46.47 MPa at 7 days. Elevated mixing temperatures accelerated geopolymerization, promoting rapid dissolution of raw materials and coagulation of the paste. As the temperature increased from 25 °C to 90 °C, the final setting time was shortened from 351 to 6 min. Extreme mixing temperatures (5 °C and 90 °C) both induced rapid setting within 15 min but through distinct mechanisms. At 90 °C, excessively accelerated geopolymerization produced gel structures encapsulating incompletely decomposed raw materials, hindering subsequent reactions and deteriorating the structure and strength. In contrast, at 5 °C, rapid setting was caused by hydrated sodium silicate crystal inclusions, which did not negatively affect the final structure or performance, as the final setting was only 15 min, with an initial compressive strength of 2.66 MPa and achieved 36.80 MPa after 7 days. This suggests that low-temperature reaction can be used as an effective method for preparing rapid-setting geopolymers.
✓ 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）