SCIENCE OF THE TOTAL ENVIRONMENT
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2021
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IF 7.963
Yawen Cai,Jinghua Feng,Xiaoli Tan,Xin Wang,Zhimin Lv,Weiwei Chen,Ming Fang,Haining Liu,Xiangke Wang
The efficient decontamination of pertechnetate ( 99 TcO 4 − ) is an essential task for managing radioactive 99 Tc in nuclear wastes . Perrhenate, (ReO 4 − ), as a nonradioactive analog, exhibits almost identical physicochemical properties as 99 TcO 4 − . Herein, a novel magnetic amine-functionalized MIL-101(Cr) (NH 2 -MIL-101(Cr)@Fe 3 O 4 ) was prepared and used to efficiently remove ReO 4 − from solution for the facile magnetic separation. A series of environmental parameters were considered to investigate the adsorption performance of NH 2 -MIL-101(Cr)@Fe 3 O 4 . Experimental results suggested that NH 2 -MIL-101(Cr)@Fe 3 O 4 has reached a satisfied adsorption capacity (~401 mg/g) and a very fast adsorption kinetics at pH 7.0. The selectivity for ReO 4 − was maintained even in the presence of interfering anions with relatively high concentrations. ReO 4 − were mainly captured by N-donor sites of the surface-decorated amine via complexation and were trapped in the cavities of modified MIL-101(Cr). NH 2 -MIL-101(Cr)@Fe 3 O 4 exhibits satisfactory adsorption performance for ReO 4 − and can be conveniently separated from wastewaters after adsorption.
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Nano Energy
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2021
·
IF 17.881
Wenrou Tian,Jiahao Qiu,Najun Li,Dongyun Chen,Qingfeng Xu,Hua Li,Jinghui He,Jianmei Lu
Piezocatalysis that converts mechanical energy into chemical energy plays an important role in environmental purification and energy regeneration. In this work, a piezoelectric membrane of carbon nanofibers coated by few-layers SnS 2 nanosheets , a typical layered transition metal dichalcogenides (TMDs), for the first-reported piezocatalysis of hexavalent chromium (Cr (VI)) and bisphenol A (BPA). A boosted removal efficiency of Cr (VI) and BPA under ultrasonication are 3 and 4 times higher than that under illumination, respectively, which is attributed to the built-in electric field and band bending derived from the piezoelectricity of SnS 2 as well as the outstanding electronic liquidity of CNFs substrate. It was also found that the most oxidizing ·OH can be generated in SnS 2 /CNFs for piezocatalytic oxidative degradation of BPA compared to the absence of ·OH under illumination. Finally, the possible piezocatalytic mechanism of SnS 2 /CNFs is proposed. So it provides a new view on piezocatalysis of TMDs for environmental remediation by collecting mechanical energy.
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APPLIED SURFACE SCIENCE
·
2021
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IF 6.707
Xiao Zhang,Ping Yang,San Ping Jiang
Photo-catalytic reduction of highly toxic Cr(VI) using graphitic carbon nitride (g-C 3 N 4 ) based photocatalysts under visible light irradiation condition has been attracting considerable attention recent years. Here, we report the development of heterostructured NiCo-layered double hydroxides (LDHs) grown horizontally on g-C 3 N 4 nanosheets with different degrees of crystallinity (amorphous to crystalline), NiCoLDH/g-C 3 N 4 , with high photocatalytic activity for the reduction of toxic hexavalent chromium ions (Cr(VI)) as well as high adsorption capability for congo red (CR) photodegradation under visible light irradiation. The presence of NiCoLDH nanoparticles promotes the adsorption of the anionic pollutants while g-C 3 N 4 in the heterostructure promotes fast photodegradation of CR and reduction of Cr(VI). The NiCoLDH/g-C 3 N 4 composite prepared using amorphous-crystalline g-C 3 N 4 homojunctions shows the best adsorption performance. The kinetic data demonstrates improved correlation coefficient for the pseudo-second-order (R 2 > 0.99) and Freundlich isotherm model. The NiCoLDH/g-C 3 N 4 composite shows an improved separation efficiency of photogenerated electron and hole pairs, leading to its improved Cr(VI) adsorption and photo-reduction performance. The monolayer adsorption capacities of CR and Cr(VI) of the NiCoLDH/g-C 3 N 4 heterostructured composite can be as high as 1100 and 46 mg/g at 30 °C, respectively. This work provides new perspectives for the development of highly efficient g-C 3 N 4 -based composite photocatalysts for wastewater treatment related applications.
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MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
·
2021
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IF 3.927
Zhaohui Wu,Zhongfu Li,Min Wu,Jie Shen,Wenhui Feng,Xue Li,Difa Xu,Shiying Zhang,Nan Ma
It is inevitable to form invalid Type I heterostructure of BiOCl/bismuth-based photocatalysts due to the wide bandgap of BiOCl , which could only transfer the charge carriers efficiently, rather than separate. Herein, two-dimensional (2D) Type I van der Waals heterostructure of BiO 2-x /BiOCl nanosheets were prepared through a solvothermal route, and massive defects and multiple pores were in-situ constructed on the BiO 2-x /BiOCl nanosheets simultaneously. The defective and porous van der Waals structure of BiO 2-x /BiOCl ultrathin nanosheets possessing enhanced internal electric field , induced defect level, and reduced interfacial barriers, promoting both efficient transfer and separation of charge carriers. Furthermore, the massive defects of BiO 2-x /BiOCl porous nanosheets provided higher reactivity owing to its more hydrophilic surface . As a result, the BiO 2-x /BiOCl nanosheets boosted the photocatalytic performance of Cr (VI) reduction and Rhodamine B (RhB) degradation when employing LED as simulated solar light. Based on the results, a plausible photocatalytic mechanism of Cr (VI) removal and RhB photodegradation was illustrated. We expected that this work could provide a feasible route to design distinctive heterostructure photocatalysts for improved photocatalytic performances under simulated solar light.
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CHEMOSPHERE
·
2021
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IF 7.086
Jinxiong Wu,Xiuling Yan,Li Li,Jiahua Gu,Ting Zhang,Lanlan Tian,Xintai Su,Zhang Lin
Coal gangue (CG) is one of the largest industrial solid wastes in the world produced during the process of coal mining . The accumulation of CG is easy to cause ion leakage , which is harmful to the environment and human body. The recovery and utilization of CG are imminent. In the process, a hierarchical porous carbon (HPC) adsorbent with excellent adsorption property for Cr(VI) and rhodamine B (RhB), was prepared from CG by a two-step method and characterized by SEM, TEM, XRD , XPS, TPD and BET. The results revealed that the specific surface area of HPC is up to 2012.7 m 2 g −1 , and its adsorption capacities for Cr(VI) and RhB are reached 320.51 and 3086.42 mg g −1 . The adsorption mechanism of RhB was the synergetic effect of physics and chemistry. While XPS results suggested that hierarchical porous carbons (HPCs) only have a chemisorption effect on Cr(VI). This study provided an idea for the preparation of HPCs from CG to remove inorganic and organic pollutants such as heavy metal Cr(VI) and RhB in water.
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Journal of Environmental Chemical Engineering
·
2020
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IF 4.3
Xing Chen,Xu-Xu Ke,Yao Liu,Rohan Weerasooriya,Heng Li,Yu-Cheng Wu
Chromium readily undergoes redox speciation, and Cr(VI) oxidation state is ubiquitous and mobile in the environment. Under physiological conditions, Cr(VI) reduction yields species as Cr(V) or Cr(VI), which shows reactivity towards DNA damaging. Therefore, accurate detection of Cr species in the environmental compartment is of utmost importance. In compliance with green chemistry, Au/mpg-C 3 N 4 nanocomposites were successfully fabricated by ultra-violet photo-reduction without a reducing agent. The Au/mpg-C 3 N 4 nanocomposites were characterized by scanning electron microscope (SEM), X-ray diffractometry (XRD), X-ray photoelectron spectrometry (XPS), and infrared spectrophotometry. Well-dispersed gold nanoparticles with an average diameter of 50 nm decorated on mpg-C 3 N 4 . We developed a method to determine Cr(VI) with excellent sensitivity (0.002196 μA/ppb) and detection limit (14.7 ppb) using Au/mpg-C 3 N 4 modified glassy carbon working electrode by linear sweep voltammetry (LSV). The same electrode can use in real-time Cr(VI) monitoring using amperometry. The new sensor is stable and free from interferences from other species in natural water, and it can also be used in real-time Cr(VI) monitoring over wide concentration ranges.
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RSC Advances
·
2020
·Vol. 10
·期 46
·27775-27787
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IF 3.119
Qining Liu,Honghui Liu,Huixia Chen,Xinrun Wang,Dahai Hu,Xichuan Cheng,Hongbin Xu
In this paper, the reoxidation behaviours of CrOOH and Cr(OH)3 are investigated as the major reduction products of Cr(VI). The atmosphere oxidation of Cr(III) is studied in the environment of soil without manganese and hydrogen peroxide. The influence of temperature and pH value on the oxidation rate of Cr(III) is examined by Experiment methods in details. According to the experimental results, the oxidation of Cr(III) is promoted in the environment with high pH value, however, the oxidation process is stable with temperature. The oxidation process of CrOOH and Cr(OH)3 are theoretically researched by thermodynamic calculation and density functional theory (DFT) simulation. The results of DFT indicate that both CrOOH and Cr(OH)3 are oxidized during the chemical adsorption process of O2 in alkaline environment. With the transformation from Cr(III) to Cr(VI), the Cr–O covalent bond forms in the adsorption process. The crystal structure difference between CrOOH and Cr(OH)3 leads to the different oxidation reaction between O2 and Cr(III). The significant alteration of oxidation process in (110), (310), (321) crystal planes is also observed indicating the crystal orientation dependence. Based on the chemical reaction kinetics, the chemical equivalent constant K of CrOOH is higher than Cr(OH)3, illustrating higher chemical stability in air. In summary, both experimental study and theoretical analysis on the reoxidation phenomenon of Cr(III) reduced from Cr(VI) in natural environment demonstrate that not only the external factors such as temperature and pH value but also the crystal structure of Cr(III) compound have dramatic influence on the oxidation process.
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FUEL
·
2021
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IF 6.609
Zeyu Xue,Lu Dong,Zhaoping Zhong,Xudong Lai,Yaji Huang
Raw montmorillonite (MMT) was modified by intercalation-exfoliation method to improve the capture capacity of heavy metals (Pb, Zn, Cr and Cd) during coal combustion . Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) Spectroscopy and Brunner-Emmett-Teller (BET) indicated that intercalation agents cetyltrimethylammonium bromide (CTAB) and sodium dodecyl benzene sulfonate (SDBS) could be successfully inserted into the interlayer of MMT during the intercalation step, additionally exfoliation process could peel off the MMT into fine flakes. The co-combustion of coal and MMTs was conducted in a tube furnace from 900 to 1300 °C. Results indicated that with the increase of temperature, the retention ratio of Pb, Zn and Cd gradually decreased, especially higher than 1200 °C with a great capture capacity reduction, whereas for Cr, it rose first and then decreased. The capture performance of modified MMT on Pb, Zn and Cr was obviously improved. However, for Cd, adverse effect was observed, of which the capacity was even worse than that of raw MMT in some cases. According to the mechanism analysis, the intercalation-exfoliation modification of MMT primarily enhances the chemisorption of heavy metals by exposing more active sites, which facilitates the fixation of heavy metals in the form of aluminosilicates .
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ANALYTICAL CHEMISTRY
·
2020
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IF 6.785
Ningyi Chen,Bingcai Pan
Most metal probes based on gold nanoparticles (AuNPs) are designed for free metal ions in synthetic waters, and very few are applicable in the detection of metal–organic complexes ubiquitous in real water samples. In this study, we proposed a novel colorimetric nanoprobe strategy for complexed Cr(III) species based on the analyte-induced aggregation of AuNPs, as coated by a cationic surfactant tributylhexadecylphosphonium bromide (THPB) instead of traditional carboxyl modifiers. Such a detection system could be realized via both naked eye and/or UV–vis spectroscopy with detection limits of 8.0 and 0.29 μM, respectively, much lower than its allowable maximum level in industrial effluent as regulated by China EPA (1.5 mg Cr/L, ∼30 μM). The proposed detection system also exhibits high selectivity against various interfering substances including free ions, small organic molecules, and other metal–citrate complexes. The unique hydrolysis and extremely slow decomplexation of Cr(III) are believed to favor the formation of the specific interaction between Cr(III)–citrate and THPB-AuNPs, as verified by X-ray photoelectron spectroscopy characterization, thus endowing the nanoprobe with specific discrimination of the complexed Cr(III) via the aggregation of THPB-AuNPs. Also, the THPB-AuNPs could be stored at room temperature for 30 days and maintain constant detection performance. Moreover, the quantitative detection of Cr(III)–organic complexes with the background of various real water samples agreed well with that based on inductively coupled plasma atomic emission spectrometry, making it an attractive alternative for on-site detection of authentic samples containing Cr(III)–organic species.
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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2021
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IF 4.464
Cheng Liu,Lei Jin,Jia-Qiang Yang,Fang-Zu Yang,Zhong-Qun Tian
In this paper, the effects of complexing agents (oxalic acid and glycine) and Fe(II) ions on the electro-reduction of Cr(III) ions are studied carefully. Based on the electrochemical analyses, both the complexing agents and Fe(II) ions can obviously decrease the cathodic polarization in the electro-reduction of Cr(III) ions, and the Fe(II) ions can also be co-deposited with Cr(III) ions. One water molecule in [Cr(III)(H 2 O) 6 ] 3+ ion is substituted by one oxalic acid or glycine to form an electrochemically active penta-aqua-Cr(III) coordination ion. In situ infrared spectroscopy and energy dispersive spectroscopy reveal the typical induced-deposition mechanism of ferrochrome alloy. Fe(II) ions are firstly reduced to Fe crystal nuclei, then Cr and Fe atoms grow on the Fe nuclei to form ferrochrome alloy.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2021
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IF 6.953
Huimei Shan,Chunya Zeng,Chaoran Zhao,Hongbin Zhan
This study is the first to evaluate the effects of Iron oxides (FeO x ) species and their decoration on graphene oxide/chitosan (GO/CS) composites for Cr(VI) removal and the possibility of Fe secondary pollution. Results show that Fe(III) is a better decoration material than Fe(II) and decoration through immersion-evaporation shows a higher adsorption capacity of Cr(VI) ( Q e ) than co-precipitation. Fe 2 O 3 -GO/CS as the only eco-friendly composite for enhanced Cr(VI) removal is further used for batch adsorption experiments, characterization, kinetics, isotherms, and thermodynamic studies. It is found that Cr(VI) removal mainly includes electrostatic attraction between Cr(VI) oxyanions and surface -NH 3 + and -OH 2 + , and the adsorbed Cr(VI) partially reduces to Cr(III). Q e increases with the increasing initial Cr(VI) concentration, contact time, and temperature, while decreases with the increasing pH and mass and volume ratio (m/v). The coexisting ions (Cl − , NO 3 − , SO 4 2− , PO 4 3− , As, Fe, and Pb) can cause an obvious decrease of Q e . The removal efficiency ( R e ) and Q e are 94.3% and 83.8 mg/g, respectively under the optimal conditions. After five times of regeneration, R e is still as high as 84% and Q e drops about 2.6%. Cr(VI) adsorption is spontaneous and endothermic, which is best fitted with the Sips model, and the fitted maximum Q e is 131.33 mg/g.
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JOURNAL OF POLYMERS AND THE ENVIRONMENT
·
2020
·Vol. 28
·期 8
·2199-2210
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IF 2.572
Pei Ruihan,Li Qiqi,Liu Jianting,Yang Guifang,Wu Qiong,Wu Minya,Tong Shengxuan,Lv Yuancai,Ye Xiaoxia,Liu Yifan,Liu Minghua
Abstract Removal of low content of Cr(VI) from water is a critical challenge for water environment protection. Herein, an acrylamide-thiosemicarbazide cellulose aerogels (ATC) was designed by dissolving, grafting and freeze-drying to introduce thiosemicarbazide onto acrylamide-cellulose aerogels (AMC) via Schiff based reaction. The resultant ATC was further employed as an efficient adsorbent to remove low content of Cr(VI) from wastewater by adsorption and reduction. The SEM, FT-IR, and BET results showed that the ATC was composed of well-developed pore structure and owned functional groups such as –NH 2 , C–S and C=S groups. Experimental results indicated that ATC exhibited excellent removal efficiency for 99% under low initial concentration (0.1–10 mg/L). The adsorption isotherms demonstrated ATC adsorbent according to a monolayer adsorption behavior following the Langmuir model with a calculated maximum adsorption capacity of 83.40 mg/g at pH 3, and the adsorption kinetics well obeyed the pseudo-first-order kinetic model. Importantly, the maximum effluent concentration of Cr(VI) was lower than 0.045 mg/L, meeting the standard of WHO (50 μg/L). Furthermore, the main removal mechanisms involved the synergistic effect of electrostatic interactions, reduction and chelation between the positively charged functional groups of adsorbent and the anionic Cr(VI) ions. Graphic Abstract
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危险品化学品经营许可证（带存储）