APPLIED CLAY SCIENCE
·
2016
·
IF 2.586
Tao Wu,Zhifen Wang,Qingmei Li,Guoxiang Pan,Jinying Li,Luc R. Van Loon
In order to understand the diffusion properties of anionic radionuclides (RN) in bentonite in the presence of organic compounds with chelating and reducing properties, the effect of humic acid (HA), citrate, oxalate and formate on Re(VII) diffusion was investigated by a through-diffusion method under different pH (pH 7.0 and 10.0) and temperature conditions (10–65 °C). When the molar ratio of oxalate to Re(VII) was higher than 1:1, the accumulated mass and flux were observed to decrease drastically as a function of time. It can be explained by photocatalytic impact of Fe(III) on the reduction of Re(VII) to insoluble Re(IV) by oxalate. Thus, the diffusion of Re(VII) was also observed to decrease in the presence of minor citrate, oxalate and formate. Effective diffusion coefficient (D e ) values decreased from 8.7 × 10 − 11 m 2 /s to (5.1–5.9) × 10 − 11 m 2 /s. In contrast, HA had no significant impact on Re(VII) diffusion. The D e values of 1.54 × 10 − 11 and 6.5 × 10 − 12 m 2 /s were obtained at pH 7.0 and 10.0, respectively. HA thus neither has an effect on the speciation of Re(VII) nor does it change the charge of the surface. The latter is probably due to the fact that HA preferentially interacts with the aluminol sites of the montmorillonite edges without changing the zeta potential of the surface. The dependence of D e of Re(VII) on temperature in the absence and presence of citrate or formate was described by the Arrhenius equation . The activation energy, E a , was in the range of (20.7–25.1) kJ/mol, demonstrating that Re(VII) diffusion followed a pore water diffusion model .
研究领域:
环境科学
·
放射化学
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高影响因子
WATER AIR AND SOIL POLLUTION
·
2023
·Vol. 234
·期 4
·1-13
·
IF 2.9
Ma Lijuan,Linghu Shanshan,Chen Zhichong,Wang Shuoyuan,Gu Hao,Pan Tao,Chen Xiurong
The diffusion of odour caused by excavation disturbance during the restoration of pesticide sites adversely affects the surrounding environment. Therefore, it is essential to develop a new type of odour inhibitor that has both adsorption and oxidation functions and can effectively block odour. In this study, bentonite-modified cetyltrimethyl ammonium bromide (CTAB) was synthesised, and the structural changes of bentonite before and after modification were analysed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and other characterisation methods. Urea peroxide was loaded on modified bentonite (150C-Bent) by in situ synthesis method, and the preparation conditions were optimised. The effects of temperature, humidity and species on the adsorption behaviour and adsorption kinetics were studied by adsorption experiments. It is demonstrated that CTAB is embedded in bentonite through ion exchange, and the interlayer spacing expands from 1.42 to 3.11 nm. The optimal loading mass ratio of modified bentonite to urea peroxide was 1:1.5 and pH was 3. When the relative humidity is 54.3% and the temperature is 55 °C, the removal effect of paraxylene is the best; the optimal removal reached 82.4%. The adsorption behaviour of 1.5UHP-Bent conforms to the pseudo-second-order kinetic adsorption model. The adsorption pathway of paraxylene on UHP-Bent mainly includes partition effect and hydroxyl radical capture.
研究领域:
环境科学
·
化学工程
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DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Qi Wang,Baker Rhimi,Hui Wang,Chuanyi Wang
To solve the aggregation problem of TiO 2 nanomaterials and improve the catalytic efficiency, F-doped TiO 2 /exfoliated bentonite (TF/EB) composite was prepared by dispersing F-doped TiO 2 (TF) nanoparticles on an exfoliated bentonite (EB) using a facile sol–gel method. The exfoliated bentonite was prepared by liquid-exfoliation method from the natural bentonite (B). The prepared samples were applied for toluene degradation in gas phase under UV and visible light irradiation. The as-prepared TF/EB composite exhibited higher toluene degradation efficiency than that of pure TiO 2 , F-doped TiO 2 and TF/B composite. Results indicated that the calcination temperature and the initial F/Ti atom ratio of reaction precursors greatly affected the photocatalytic activity towards toluene degradation. The best photocatalytic performance was obtained by the sample calcinated at 400 °C with an initial F/Ti atom ratio of 5%. The improved photocatalytic performance is ascribed to a series of benefits introduced by F-doping and exfoliation process. The presence of F - ions increases the percentage of exposed reactive {0 0 1} facets on TiO 2 . Moreover, F - ions incorporated into the TiO 2 lattice generate oxygen vacancies and Ti 3+ defects, which influence the transfer and migration of the photoinduced charge carriers and induce a visible-light photocatalytic activity . Furthermore, the electrostatic interaction of negatively charged exfoliated bentonite surface leads to a more efficient separation of charge carriers.
研究领域:
环境科学
·
材料科学
·
化学工程
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DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2022
·
IF 5.518
Xinyu Zhou,Jia Huang,Lu Han,Wenli Luo,Weifeng Lv,Hao Shen,Xinyuan Zou,Yingde Yan,Zihao Yang
Foam flooding has been widely used as an effective technology to enhance oil recovery. As a thermodynamically unstable system, foam is prone to disproportionation and coalescence especially in high-salt or high-temperature environments, which limits the effective plugging performance in complex reservoirs. In this paper, a commercial anionic-nonionic compound surfactant was used as the foaming agent, and low-cost sodium bentonite , which is optimized from three types of inorganic particles, was used as the foam stabilizer . The compound system has a foaming volume of 605 mL and a half-life of 1260 s under the environment of 90 °C and 271207 mg/L. The Nano Measurer software is proposed to calculate the foam diameter under different conditions. Furthermore, the effect of salinity, temperature, foaming agent, and stabilizer concentration on foam properties were investigated, and the mechanism of sodium bentonite on foam stability was explored. This study may provide some experimental basis and theoretical explanation for the development of particle-stabilized foam.
研究领域:
石油工程
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材料科学
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高影响因子
BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY
·
2022
·Vol. 110
·期 1
·1-7
·
IF 2.807
Gu Xinfeng,Mo Huijing,Wang Lei,Zhang Lianyi,Ding Zhuhong
Transport of Cr(VI) at the presence of bentonite colloid was carried out in saturated porous media of 16–18 mesh and 40–60 mesh sand columns. Effects of flow rate, pH, ion strength, humic acid and bentonite concentrations on Cr(VI) migration were investigated. The results show that the increase of flow rate accelerated the breakthrough of Cr(VI) and BP, but the transport mass of dissolved Cr(VI) decreased by ~ 15.0% when flow rate increased to 2.5 ml min −1 . Increasing IS to 10mM resulted in decrease of Cr(VI) transport mass by 6.86%–21.4%. Increase of pH and decrease of bentonite concentration favored the transport of dissolved Cr(VI). Humic acid had little effect on transport amount of Cr at pH7. Cr(VI) transport was dominated by the dissolved Cr(VI). The transport data of dissolved Cr(VI) were well described by the two-site model. The presence of BP reduced total Cr(VI) transport mass in co-transport.
研究领域:
环境科学
·
土壤学
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DOI
PubMed
高影响因子
NUCLEAR TECHNOLOGY
·
2022
·
IF 1.667
Yanhui Wang,Qiao Jiang,Yexin Yang,Jianfeng Cheng,Chenyang Bao,Yuelong Pan,Yu Liu,Gang Yang,Yangchun Leng,Xianguo Tuo
The alteration of the morphology of bentonite, a key barrier to isolating high-level radioactive waste in deep geological repositories under long-term interaction with groundwater, was studied. Bentonite colloids were prepared from Gaomiaozi bentonite, and its various properties were analyzed by various characterization methods. The effects of various factors on the adsorption of Cs(I) and Co(II) on bentonite colloids were investigated by batch static adsorption experiments. The results showed that the colloids were mainly composed of montmorillonite and were lamellar in shape, with a zeta potential of −enton mV and an average size of approximately 209.10 nm. The adsorption of Cs(I) and Co(II) by the colloids was a rapid process, and 31.78 and 88.24 mg/g, respectively, were adsorbed at equilibrium. Pseudo-second-order kinetic fitting showed that chemisorption plays a dominant role and acid-base interactions affect adsorption by influencing the stability of colloids and the chemical form of simulated nuclides. This work can be helpful for evaluating the safety of waste repositories.
研究领域:
环境科学
·
放射性废物管理
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DOI
高影响因子
Plasma Processes and Polymers
·
2024
·Vol. 21
·期 7
·2400001
·
IF 2.9
Shouxian Tang,Shiji Qin,Zhengduo Wang,Lijun Sang,Jiushan Cheng,Zhongwei Liu
A solution combustion synthesis (SCS) process to prepare nickel catalyst over bentonite (NiO/Ben) is reported. Compared to the traditional impregnation method, NiO/ben produced by SCS has smaller nickel particle size and higher dispersion. With a metal loading of 20 wt%, the afforded NiO/Ben demonstrates excellent catalytic activity for CO 2 methanation in a dielectric barrier discharge reactor. In certain discharge conditions (H 2 :CO 2 ratio of 5 in feed gas, discharge input power of 45 W, and gas hourly space velocity of 11 320 h − 1 ), CO 2 conversion and CH 4 selectivity are as high as 55.8% and 84.6%, respectively. Under the conditions of plasma configuration, the strong interaction between the nickel species and the support plays an important role in the CO 2 methanation process.
研究领域:
化学工程
·
环境科学
·
催化科学
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DOI
高影响因子
KERNTECHNIK
·
2023
·Vol. 88
·期 5
·556-565
·
IF 0.5
Qifeng Jiang,Weigang Liu,Yuxin Liao,Haonan Li,Junhan Li,Jiahui Feng,Zimin Zhang,Yuzhen Sun,Yuxin Chen,Jiachen Guo,Xuebin Su,Rong Hua
Bentonite exhibits obvious geological characteristics in different areas, and its chemical composition varies. To investigate the impact of these variations on the adsorption of Se(IV), the chemical structures and elemental contents of three types of bentonites were characterized using FTIR and XRF. By conducting a series of experiments and fitting the results with the kinetic adsorption model and the isothermal adsorption model, it was discovered that bentonite exhibits diverse adsorption modes for Se(IV). In acidic environments, the adsorption mode primarily involves forming an outer-sphere complex, whereas in neutral and alkaline environments, the primary mode is to form an inner-sphere complex. Zhi-Shin bentonite, which has low alumina content and high iron oxide content, demonstrates poor adsorption effectiveness on Se(IV) at low temperatures (less than 45 °C), but exhibits good adsorption effectiveness at high temperatures (more than 50 °C). Conversely, bentonite with high alumina content and low iron oxide content demonstrates the opposite effect. Furthermore, for bentonite with high iron oxide content, Se(IV) will form more inner-sphere complexes with iron oxide, and the adsorption behavior is not easily affected by changes in ionic strength and pH.
研究领域:
环境科学
·
地质学
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DOI
高影响因子
JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2022
·Vol. 331
·期 5
·2311-2317
·
IF 1.754
Wu Tao,Geng Zilong,Feng Zhengye,Pan Guoxiang,Shen Qiang
The diffusion of Re(VII), Se(IV) and Cr(VI) in compacted Gaomiaozi bentonite was conducted by an integrated diffusion setup. The effective diffusion coefficient and the rock capacity factor of Re(VII), Se(IV) and Cr(VI) were measured. Re(VII) and Cr(VI) were excluded from the surface of bentonite particles with an accessible porosity of 0.40 and 0.23. The geometric factor decreased in a sequence of Cr(VI) < Se(IV) < Re(VII), indicating that Cr(IV) had a lower tortuosity, a larger diffusion pore diameter, and a stronger anionic exclusion effect from the surface of bentonite platelets.
研究领域:
环境科学
·
地球化学
·
材料科学
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DOI
高影响因子
JOURNAL OF ENVIRONMENTAL MANAGEMENT
·
2024
·
IF 8
Longfei Zhang,Ping Wang,Xiqing Wang,Qi Zhang,Yunpu Wang,Yuhuan Liu,Lantian Zhao,Roger Ruan,Xian Cui
Contamination of heavy metals has always been a pressing concern. The dry-wet alternately treated carboxymethylcellulose bentonite (DW-CB) was successfully prepared by intercalating bentonite (BT) with carboxymethyl cellulose (CMC) obtained by solvent processes using enzymatically digested wastepaper as cellulosic raw material, and the adsorption capacity of Cu 2+ on DW-CB in aqueous solution was investigated. A 98.18 ± 2.31 % removal efficiency was achieved by 4 g/L of DW-CB after 8 h in a solution containing 100 mg/L of Cu 2+ , which were 4.1 times and 1.5 times of that of BT and adsorbent prepared without alternating dry-wet process, respectively. The introduction of –COOH groups during the preparation of DW-CB enhanced the electrostatic interaction between DW-CB and Cu 2+ , which was the main driving force for Cu 2+ removal. The pseudo-first-order kinetic model and Langmuir model better described the adsorption process and adsorption capacity of Cu 2+ on DW-CB. DW-CB still showed high removal of Cu 2+ (19.61 ± 0.99 mg/g) in the presence of multiple metal ions , while exhibiting the potential for removal of Zn 2+ , Mg 2+ and K + , especially Mg 2+ (22.69 ± 1.48 mg/g). However, the interactions of organics with Cu 2+ severely affected the removal of Cu 2+ by DW-CB (removal efficiency: 17.90 ± 4.17 % - 95.33 ± 0.27 %). In this study, an adsorbent with high targeted adsorption of Cu 2+ was prepared by utilizing wastepaper and BT, which broadened the way of wastepaper resource utilization and had good economic and social benefits .
研究领域:
环境科学
·
材料科学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
·
2026
·
IF 1.7
Li Shiyu,Fu Chengyun,Zhou Duo,Tian Qiang,Henderson Mark Julian,Zhu Shan,Yan Minhao
The adsorption of Sr 2+ and Cs + onto Gaomiaozi bentonite colloids (GMZC) was investigated to evaluate their role in radionuclide migration. The results show that within a concentration range of 20–100 mg·L⁻ 1 for Sr 2+ and Cs + , the distribution coefficient decreases with increasing ion concentration. The mechanistic study indicates that the adsorption of Sr 2+ is predominantly governed by surface complexation, whereas that of Cs + is mainly driven by ion exchange. Furthermore, Sr 2+ induces structural ordering of GMZC layers and promotes particle aggregation. However, in Na-Cl-SO 4 groundwater, the bentonite suspension showed poor stability and a significantly weakened adsorption capacity for both 90 Sr and 137 Cs, demonstrating the decisive impact of water chemistry on its barrier function.
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高影响因子
PHYSICA SCRIPTA
·
2025
·Vol. 100
·期 6
·065916
·
IF 2.6
Pouria Pourhosseinhendabad,Parisa Z Firouzabadi
Bentonite clay, nano-bentonite, and nano-clays are used in many industries such as medical, water purification, food processing, and drilling mud. But because impurities in low-grade bentonite occur, its efficiency is limited; therefore, purification and modification are carried out to enhance its quality. Cetyltrimethylammonium bromide (CTAB), cationic modifier, dispersants, and milling are used in this study's improved process for synthesizing nano-bentonite and industrial bentonite purification. CTAB was the preferred choice since it possessed the ability to modify further such parameters as surface charge, hydrophobicity, and cation exchange capacity, thus rendering bentonite more effective for its applications. The removal of impurities was mainly facilitated by the dispersants during sedimentation and centrifugation. The best sample, BMP 2 h, has shown a tremendous reduction in the cristobalite and calcite impurities with an increase in the beidellite phase as confirmed by x-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The process reduced particle size from raw bentonite 121.75 μm to 1.07 μm of BMP 2 h, which enabled improved dispersion. The enhanced purity and changed behavior of nano-bentonite reveal its potential for future industrial use in water treatment, catalysis, and drilling mud. This optimized method offers a cost-effective and efficient path to high-quality nano-bentonite, solving the limitations of current purification methods.
研究领域:
材料科学
·
环境科学
·
化学工程
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DOI
高影响因子
危险品化学品经营许可证（带存储）