Journal of Cleaner Production
·
2022
·
IF 11.072
Changsong Zhao,Yongpeng Wang,Mengxi Cheng,Hailing Zhang,Yuanyou Yang,Ning Liu,Jiali Liao
Column reactors and batch experiments were conducted to investigate the performance and mechanism of uranium (U) immobilization enhanced by extracellular polymeric substances (EPS) from anaerobic granular sludge (ANGS). Successful remediation of anoxic U-contaminated groundwater was achieved using ANGS-inoculated column reactors (all higher than 98% of U removal rate for the three columns at hydraulic retention time of 72-h), and parameters (hydraulic retention time, nitrate content, the type and content of the external carbon sources) influenced the reactor performance. 306-day column studies implied the enhanced U immobilization by EPS, where EPS acted as energy source, electron donors and U reservoir with a contribution of 3.5–6.8% to total U removal by ANGS. Results in 26-h batch experiments further demonstrated that U immobilization performance of ANGS could be promoted (6.4–22%) by EPS through adsorption and reduction. EPS induced the precipitation of U(VI) and U(IV) particulates, and amino and carboxyl groups were the main functional groups for EPS binding with U. Complexation was confirmed between humic acids in EPS and U. The interaction mechanisms between U and EPS were directly evidenced to involve complexation, induced particulate formation and reduction.
研究领域:
环境科学
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微生物学
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DOI
高影响因子
JOURNAL OF RARE EARTHS
·
2025
·
IF 7.2
Jiaxin Pan,Xiaowei Huang,Longsheng Zhao,Depeng Liu,Ting'an Zhang,Zongyu Feng
The investigation of the leaching mechanisms of ion adsorption rare earth ores (IAREO) using MgSO 4 is significantly hindered by the complex mineral composition. In this study, the direct analogue of the natural IAREO sample, Y-kaolinite, was prepared and used to investigate the leaching mechanisms of rare earths from kaolinite under varying initial MgSO 4 concentrations and pH. The results of X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray absorption fine structure (XAFS) data indicate that the Y-kaolinite prepared exhibits a similar composition, micromorphology and coordination structure with nature IAREO sample. The coordination number and bond length of Y–O are 9.2±1.4 and 0.23±0.010 nm, respectively. The results of batch desorption experiments and sequential chemical extractions show that lowering the initial pH from 5.00 to 2.00 significantly enhances the desorption of rare earths from Y-kaolinite. Specifically, the additional desorption amounts are 0.52 mmol/kg for inorganic hydroxy Y (Hy-Y) and 0.40 mmol/kg for ion-exchangeable Y (Ex-Y). The enhancement mechanism was revealed by density functional theory (DFT) and Visual MINTEQ. The desorption of Hy-Y and Ex-Y is directly and indirectly enhanced by hydrogen ions, respectively. The desorption of Hy-Y is consistent with the dissolution behavior of the Y hydroxyl compound at lower pH. The desorption of Ex-Y is promoted by [Al(H 2 O) 6 ] 3+ released from Hy-Al by hydrogen ions. Additionally, when the concentration of MgSO 4 is 100 mmol/L and initial pH is 2.00, the desorption rate of rare earths is 87.1%, while the adsorption rate of magnesium is 63.1% and the stoichiometry ratio of Y 3+ to Mg 2+ is 1.04, which indicates that adequate hydrogen ions reduce the consumption of MgSO 4 and enhance the leaching of rare earth. These finding provide valuable insights into optimizing the selective leaching of rare earths from IAREO.
研究领域:
地球科学
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矿物加工
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环境化学
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产品关联
DOI
高影响因子
Surfaces and Interfaces
·
2023
·
IF 6.2
Lei Zhou,Xiangyu Xi,Haidong Li,Han Song,Qiong Mei,Yuankun Yang,Shu Chen,Qunwei Dai,Faqin Dong
Vanadium contamination has gained increasing attention around the world and it is urgent to develop feasible approach to tackle this growing pollution (e.g., vanadate). Herein, density functional theory (DFT) calculations combined with batch experiments were used to systematically evaluate the capacity of Mg(OH) 2 to adsorb vanadate , by investigating the impacts of different exposed facet and surface OH defect on the structure configurations, adsorption energy and the efficiency of vanadate adsorption. DFT calculations suggested that although the capacity of vanadate adsorption on the facets of Mg(OH) 2 would be obviously influenced by the formation of various coordination complex (e.g., monodentate, bidentate and tridentate) on each facet, the capacity for these facets of Mg(OH) 2 towards vanadate adsorption followed the order: (100) > (001). Moreover, such a vanadate adsorption was further enhanced by the presence of surface OH defect, owing to altered densities of states (DOS) of the adsorption site. Batch experiments verified the defect-rich Mg(OH) 2 was favorable to adsorb vanadate, and both (001) and (100) facet play the great roles. This molecular-level understanding of the facet-dependent and defect-enhanced adsorption behavior of Mg(OH) 2 toward vanadate provides a useful insight into designing and applying effective adsorbents for the removal of heavy metal oxyanions.
研究领域:
环境科学
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材料科学
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化学
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产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2024
·
IF 0
Cai Fangfei,Zhang Xiaoying,Ma Funing,Qi Linlin,Lu Di,Dai Zhenxue
The distribution coefficient ( K d ) of radionuclides is a crucial parameter in assessing the safety of high-level radioactive waste (HLW) geological repository. It is determined in the laboratory through batch and column experiments. However, differences in obtained K d values from distinct experiments have not been thoroughly assessed and compared. This study evaluated strontium (Sr) sorption on different granite materials using static batch and dynamic experiments (column and core-flooding experiments). The results from batch sorption experiments showed higher Sr sorption on granite under acidic and strongly alkaline conditions, low solid–liquid ratios, and low ionic strength. In column experiments, a two-site sorption model was used to simulate Sr transport in crushed granite and mixed pure minerals. The sorption of Sr on crushed granite exhibited a higher affinity than that of mixed pure minerals. The dual-porosity transport model was employed to investigate Sr transport behavior in fractured granite in the core-flooding experiment. K d obtained from batch sorption experiments are four to twenty times higher than those from column experiments, and two to three orders of magnitude higher than that from a core-flooding experiment. The results of this study provide valuable insights into safety assessment for the HLW geological repository.
研究领域:
环境科学
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放射性废物管理
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产品关联
DOI
PubMed
JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
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2017
·Vol. 314
·期 3
·1853-1864
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IF 1.282
Zhao Wenhui,Lin Xiaoyan,Qin Yao,Cai Huaming,Chen Yalei,Luo Xuegang
The chemically oxidized porous carbon (m-a-NC) materials were prepared by oxidation and activation of N-doped carbon (NC) materials which were produced from the glucose-urea resin primary carbon. Simultaneously, the batch experiments were carried out to investigate the adsorption of U(VI) onto the m-a-NC materials. The m-a-NC materials exhibit the maximum adsorption capacity of 397 mg/g towards U(VI) at 298.15 K and pH = 4.5. The adsorption kinetics was well fitted by the pseudo-second-order kinetic model, and the adsorption isotherm was better described by the Langmuir model. The possible adsorption mechanism of the m-a-NC for U(VI) was ion-exchange and coordination.
研究领域:
材料科学
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环境化学
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吸附技术
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产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2019
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IF 3.131
Mi Wu,Shifeng Zhao,Mingxiu Tang,Ruisen Jing,Yifei Shao,Xijuan Liu,Yuanpeng Dong,Mingzhu Li,Qiang Liao,Guocheng Lv,Qian Zhang,Zilin Meng,Aiju Liu
The contaminantsin environment generally do not exist alone and possess different physical and chemical properties, their environmental behavior and mechanism of action in environment are more complicated. Montmorillonite was employed as adsorbent to remove tetracycline (TC) and sulfamethoxazole (SMZ) respectively and simultaneously under batch kinetic and different solution conditions. As the contaminant present singly, it only had a good effect to TC removal. The experimental data were well fitted to pseudo-second-order kinetic model, and the adsorption behavior followed the Langmuir isotherm indicated that TC adsorption was a monolayer coverage and charge-limited adsorption process . In addition, the TC molecular arrangement in the interlayer were analyzed experimentally and through simulation. While the contaminants co-exist, not only TC but also SMZ was removed effectively. SMZ adsorption mechanism were investigated through adsorption equilibrium experiment, characterization and molecular dynamics simulation . Experiment data showed that the best agreement was obtained with the Freundlich model and the adsorption mechanism was proved that SMZ was trapped by hydrophobic interaction.
研究领域:
环境科学
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化学工程
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材料科学
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产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Shuangqin Tian,Xin Shi,Shujie Wang,Yi He,Bifang Zheng,Xianhong Deng,Ziqin Zhou,Wenbin Wu,Kai Xin,Lihong Tang
With the ever-increasing challenge of heavy metal pollution, the imperative for developing highly efficient adsorbents has become apparent to remove metal ions from wastewater completely. In this study, we introduce a novel magnetic core–shell adsorbent, Fe 3 O 4 @UiO-66-PDA. It features a polydopamine (PDA) modified zirconium-based metal–organic framework (UiO-66) synthesized through a simple solvothermal method. The adsorbent boasts a unique core–shell architecture with a high specific surface area, abundant micropores, and remarkable thermal stability. The adsorption capabilities of six metal ions (Fe 3+ , Mn 2+ , Pb 2+ , Cu 2+ , Hg 2+ , and Cd 2+ ) were systematically investigated, guided by the theory of hard and soft acids and bases. Among these, three representative metal ions (Fe 3+ , Pb 2+ , and Hg 2+ ) were scrutinized in detail. The activated Fe 3 O 4 @UiO-66-PDA exhibited exceptional adsorption capacities for these metal ions, achieving impressive values of 97.99 mg/g, 121.42 mg/g, and 130.72 mg/g, respectively, at pH 5.0. Moreover, the adsorbent demonstrated efficient recovery from aqueous solution using an external magnet, maintaining robust adsorption efficiency (>80%) and stability even after six cycles. To delve deeper into the optimized adsorption of Hg 2+ , density functional theory (DFT) analysis was employed, revealing an adsorption energy of -2.61 eV for Hg 2+ . This notable adsorption capacity was primarily attributed to electron interactions and coordination effects. This study offers valuable insights into metal ion adsorption facilitated, by magnetic metal–organic framework (MOF) materials.
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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产品关联
DOI
PubMed
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Ruoxuan Guo,Yang Liu,Yingzhong Huo,Anrui Zhang,Jiahui Hong,Yuejie Ai
Covalent organic frameworks (COFs) are promising adsorbents for removing heavy metal ions , and have high crystallinity , a porous structure, and conjugated stability. N -containing functional groups are known to have great affinity for uranyl ions. In this work, to explore the peculiarity of the pyridine N structure as an efficient adsorbent, we chose 2,2′-dipyridine-5,5′-diamine (Bpy) and pyridine-2,5′-diamine (Py) as the core skeletons, and 1,3,5-triformylphloroglucinol (Tp) as the linker to synthesize two crystalline and stable N -containing COFs named TpBpy and TpPy, respectively, through a facile solvothermal method . Characterization results demonstrated that TpBpy and TpPy possessed regularly growing pore sizes, large specific surface areas and relatively strong thermal resistances . The results of batch experiments showed that both COF materials were capable of the effective removal of uranyl with uptake capacities of 115.45 mg g −1 and 291.79 mg g −1 , respectively. In addition, density functional theory (DFT) simulations highlighted the beneficial chelation effect of the double N structure in pyridine monomers for removing uranyl ions. Combining systematic experimental and theoretical analyses, the adsorption process and interaction mode of porous COFs and UO 2 2+ were revealed, to provide predictable support for the application of pyridine N -containing COFs in the field of environmental remediation.
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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理论化学
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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）