Journal of Environmental Chemical Engineering
·
2018
·
IF 0
Sefiu Abolaji Rasaki,Bingxue Zhang,Siqi Liu,Tiju Thomas,Minghui Yang
ZnO@TiCN nanourchin composites are synthesized via a solid–solid separation process followed by a wet deposition method. The composite contains TiCN nanourchins, metallurgically connected to ZnO ; the system adsorbs Cr(VI) following a pseudo-first order kinetics. This heterostructure has substantial ability to thermochemically convert the adsorbed Cr (VI) to Cr (III). Complete removal of Cr (VI) is achieved, even in the <10 ppm concentration regime. The effect of reaction time, temperature, pH value, adsorbent loading, initial concentration of Cr (VI), and thermodynamic parameters are systematically investigated. Van’t Hoff’s plot based analysis indicates that the entropy change associated with physisorption process involved is significantly positive (∼18 kJ/mol K). The process is also substantially endothermic (△H ∼ 5 kJ/mol). Kinetics improves with temperature up to 90 °C. The high entropy associated with the adsorption is attributed to a high heterogeneity factor of ∼3.9. Pseudo-second order is the best kinetic model to describe the adsorption of Cr(VI) onto the surface of ZnO@TiCN; both Freundlich and Langmuir isotherms describe the adsorption observed. Over 4 regeneration cycles, an adsorption capacity retention of >90% is observed. This novel adsorbent, with its hierarchical structure, and properties reported here, suggest that it could find applications in contemporary waste water treatment processes.
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CHEMOSPHERE
·
2016
·
IF 3.698
Wenjuan Fan,Junlian Qiao,Xiaohong Guan
A new method for Cr(VI) (0.025–8.00 mg/L) determination based on the reaction of Cr(VI) and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) in aqueous solutions was developed. The colorless ABTS reacted with Cr(VI) under strong acidic conditions ([H + ] = 3.0 or 6.0 M) producing a stable colored radical ABTS + , which could be measured spectrophotometrically at 415, 649 or 732 nm. The absorbance increase at these three wavelengths for ABTS + generation were all linear (less than 1.0% deviation) with respect to the amount of added Cr(VI) and the sensitivity were 1.099 × 10 5 , 3.720 × 10 4 , and 4.150 × 10 4 M −1 cm −1 of added Cr(VI) at 415, 649 or 732 nm, respectively. Cr(VI) of 0.025 mg/L below the discharge standard of drinking water could be detected with the method quantitatively and 0.002 mg/L Cr(VI) was determined qualitatively. The molar absorptivity of ABTS + generated was determined to be (3.69 ± 0.01) × 10 4 M −1 cm −1 at 415 nm and the reaction between Cr(VI) and ABTS had a stoichiometric factor of 1:3 in excess of ABTS. The absorbance of generated ABTS + was found to be stable in deionized water or wastewater and Cr(VI) spiked in wastewater could be determined accurately. The ABTS method also had a good anti-interference performance against Co(II) ions. Moreover, the ABTS method could be successfully used in the Cr(VI)-S(IV) system for Cr(VI) determination.
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高影响因子
CHEMOSPHERE
·
2018
·
IF 4.427
Wei Zhang,Shilu Zhang,Jing Wang,Meng Wang,Qiulai He,Jianyang Song,Hongyu Wang,Jinping Zhou
In this study, we prepared a novel hybrid functionalized chitosan-Al 2 O 3 @SiO 2 composite (FCAS) for removing hexavalent chromium [Cr(VI)] from aqueous system. Spectroscopic studies like Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and energy dispersive spectroscope (EDS) were characterized. The effects such as dosage of adsorbent, pH, contact time and initial Cr(VI) concentration were evaluated. It has been illustrated that a wide acidic condition in the pH range of 2–6 was conducive to Cr(VI) adsorption and only 10 min was required to reach about 80% adsorption. Also, the adsorption properties of prepared adsorbent such as kinetics, thermodynamics and isotherms were comprehensively studied. Additionally, the adsorption capacity barely declined even after five cycles. Studies found that FCAS with characteristics of high performance of adsorption rate and capacity and better reusability would be a potential adsorbent for wastewater treatment .
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高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2025
·
IF 3.5
Mengyao Li,Ping Wu,Xiaoli Han,Shanshan Shi,Shiping Zhang,Li Wang,Min Xu,Xiulan Huai
Adsorption-based thermal energy conversion systems offer a sustainable solution for space heating and cooling applications. However, due to the limited performance of solid adsorbents, the large-scale application of this technology still requires further research. To address this challenge, we developed a composite adsorbent by integrating a graphene oxide (GO)-modified metal-organic framework (MIL-101(Cr)) with LiCl. The material was characterized using a variety of techniques to assess its improvement in three areas: water adsorption performance, heat propagation rate and stability. The synthesized material was systematically characterized to evaluate three key performance parameters: water adsorption capacity, thermal conductivity, and cyclic stability. The optimized composite LMG-3 (90 wt% LiCl) exhibits a tenfold increase in water absorption capacity compared to MIL-101(Cr)@GO at P/P 0 = 0.3. The introduction of GO significantly increases the heat diffusion coefficient, and the material exhibits excellent cyclic stability and inhibits salt deliquescence, demonstrating its potential for adsorptive thermal storage applications.
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DOI
高影响因子
ACS Omega
·
2020
·
IF 2.87
Jia Yang,Mingyan Fu,Mingdan Tan,Yanling Tian,Xiaorui Sun,Huisheng Huang
Herein, a 3.0%-Au/Sr0.70Ce0.20WO4 sample was prepared for the photocatalytic reduction of the Cr2O72– ion. The photocatalyst was characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and ultraviolet–visible diffuse reflectance spectra. The Sr0.70Ce0.20WO4 sample presented a photocatalytic reduction activity that is better than those of the Ce-doped sample and the intrinsic sample. Thereafter, different metal elements, Cu, Ag, Au, and Pt, were used as cocatalysts, which were loaded on the Sr0.70Ce0.20WO4 sample. The 3.0%-Au/Sr0.70Ce0.20WO4 photocatalyst showed optimal photocatalytic reduction activity in a 8 vol % methanol solution (pH = 7) under visible light irradiation. The kinetic constant of the optimal one is 0.0039 min–1, which is 1.86 times that of the Sr0.70Ce0.20WO4 sample. The photocatalyst is stable enough after a 24 h photocatalytic experiment.
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PubMed
高影响因子
Analytical Methods
·
2019
·Vol. 11
·期 45
·5819-5825
·
IF 2.378
Shunzhen He,Xi Lin,Hao Liang,Fubing Xiao,Feifei Li,Can Liu,Pengfei Fan,Shengyuan Yang,Yong Liu
As a priority pollutant in the environment, hexavalent chromium (Cr(VI)) has received increasing attention. In this work, a safe, simple, low-cost, effective and sensitive colorimetric strategy for the determination of Cr(VI) was introduced based on polyvinylpyrrolidone (PVP) functionalized silver nanoparticles (PVP–AgNPs). The prepared PVP–AgNPs had good dispersibility, and exhibited a state change from dispersed to aggregated when Cr(VI) was present in pH 5.5 PBS buffer due to the special and strong coordination between PVP and Cr(VI), accompanied by a color change from bright yellow to orange. Under the optimized conditions, the concentration of Cr(VI) in the range of 1.0 × 10−7 M to 2.4 × 10−6 M showed a good linear relationship with the ratio of the absorbance at 530 nm to that at 390 nm (A530 nm/A390 nm), and the limit of detection (LOD) was 34 nM. The method also showed good precision and high repeatability in determining Cr(VI) in real water samples such as pond water, tap water and river water. The recoveries ranged from 93.5% to 104.3%, indicating the method can be used for an extensive range of practical applications.
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高影响因子
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
·
2015
·Vol. 15
·期 8
·6103-6107
·
IF 1.556
Zhang Jing,Zhang Guilong,Zheng Kang,Cai Dongqing,Wu Zhengyan
Urea was used to disperse nanoscale zero-valent iron (NZVI) for reduction of Cr(VI) to Cr(III) in aqueous solution. Scanning electron microscope and fourier transform-infrared spectra investigations demonstrated that urea could effectively increase the dispersion of NZVI resulting in
more effective reduction sites (ERS) for Cr(VI) ions. Batch reduction experiments indicated that the reductive capacity of urea dispersed NZVI (UNZVI) was significantly improved, as the reductive efficiency reached 96.8% under optimal condition compared with the raw NZVI (72.14%). Additionally,
the NZVI was stable for at least 28 days after urea treatment. The dispersion mechanism was proposed that the steric hindrance effect of the urea coating on the surface might play a key role in dispersing the NZVI particles.
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PubMed
高影响因子
ChemCatChem
·
2021
·Vol. 13
·期 16
·3601-3610
·
IF 5.686
Bing Xu,Minghui Tan,Xuemei Wu,Hailun Geng,Shengying Zhao,Jie Yao,Qingxiang Ma,Guohui Yang,Noritatsu Tsubaki,Yisheng Tan
Graphical Catalytic propane aromatization : Post-introducing Cr species to Ga/Z5 catalyst had the maximum dehydrogenated active Cr 3+ species. Propane was effectively converted, and more light alkenes from propane dehydrogenation were converted into BTX on 2Cr/GaZ5 catalyst. Active Cr 3+ species and strong interaction between Ga species and ZSM-5 zeolite on 2Cr/GaZ5 catalyst accelerated the dehydrogenation step in propane aromatization. Accelerating propane dehydrogenation in propane aromatization is vital because it is the first and rate control step. In this study, we introduced Cr to Ga/ZSM-5 by tuning its impregnation sequence and amount, which was expected to accelerate the dehydrogenation step and improve aromatization performance. The impregnation sequence of Cr on catalyst not only affected the interaction between Ga and ZSM-5, but also tuned the amount of dehydrogenation active species Cr 3+ . Due to the plenty of Cr 3+ species and strong interaction between Ga species and ZSM-5, 2Cr/GaZ5 catalyst accelerated the dehydrogenation step and improved the aromatization process. More light hydrocarbons were preferred to be produced and were further converted into BTX on 2Cr/GaZ5 catalyst. Excessive Cr on catalyst caused the formation of Cr 2 O 3 particles with worse dispersion. The aggregated Cr 2 O 3 decreased the strong acidity of catalyst, which could not further promote propane conversion and decreased the aromatization ability of catalyst.
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高影响因子
Materials
·
2025
·Vol. 18
·期 9
·2108
·
IF 3.2
Yangzhou Wang,Qianshuo Wang,Yanhao Dong,Jin Wang,Shu Chen,Zihan Wang,Fei Chen,Guixin Cao,Wei Ren,Jie Li,Wen Wan
Multiband and nodal-like superconductivity (SC) with s- + d-wave pairing symmetry have implied that tetragonal iron sulphide (FeS) is a distinctive testbed for exploring unexpected electronic correlations. In particular, the low-moment disordered static magnetism originating from the Fe moment leads to the possibility of the coexistence of magnetic orders (MOs) in the superconducting ground state via the tuning of electronic configurations. Here, guided by density functional theory (DFT) calculations, we found that slightly substitutionally doped chromium (Cr) atoms in tetragonal FeS single crystals can induce both considerable d-orbital reconstruction around the Fermi surface and a local magnetic moment of 2.4µBat each doping site, which could highly modulate the SC ground states of the host. On this basis, a clear magnetic transition and reduced anisotropy of SC were experimentally observed. In particular, SC can survive with a doping content below 0.05. This coexistence of SC and MOs suggests strong spin correlations between Cr dopants and the host through exchange coupling. Further, an electronic temperature-related phase diagram of FeS with Cr doping contents from 0 to 0.07 is also provided. These results demonstrate that the continuous injection of local moments can be a controllable method to use to tune collective orders in unconventional iron-based superconductors.
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高影响因子
BIORESOURCE TECHNOLOGY
·
2019
·
IF 6.669
Jingya Ren,Guilong Zhang,Dongfang Wang,Dongqing Cai,Zhengyan Wu
In this work, cornstalk (CS) was irradiated by high energy electron beam to obtain honeycomb-like porous CS (PCS). The PCS was loaded with ammonium sulfite (AS) and then coated by polyvinyl alcohol (PVA)-Fe 3 O 4 to obtain PCS-AS@PVA-Fe 3 O 4 . The PCS-AS@PVA-Fe 3 O 4 could reduce hexavalent chromium (Cr(VI)) to trivalent chromium (Cr(III)) by SO 3 2− , then the Cr(III) combined with PCS-AS@PVA-Fe 3 O 4 through hydrogen bonds. The resulting PCS-AS@PVA-Fe 3 O 4 /Cr with a high magnetism could be conveniently separated from water via a magnet. PCS-AS@PVA-Fe 3 O 4 /Cr showed a high performance on controlling Cr(VI) migration in soil and uptake by plant. Meanwhile, ammonium could be released from PCS-AS@PVA-Fe 3 O 4 , favoring plant growth. Therefore, this work not only provides a promising and low-cost approach to remove Cr(VI) and promote plant growth simultaneously, but also provides a new route for CS recycling, which might have a potential application value.
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高影响因子
CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Honghong Lei,Yuncheng Zhou,Peng Jiang,Wei Wang,Wenbin Cao,Yawen Xue
Cr-doped Ba 2 In 2- x Cr x O 5+ y (0 ≤ x ≤ 0.5) orange-brown inorganic oxides have been successfully synthesized by solid-state reaction. X-ray diffraction (XRD) patterns show that their crystal structures transform from orthorhombic to cubic by increasing the Cr doping amount. Field emission scanning electron microscopy (FESEM) measurements show powder particles of irregular shape with average particle size of about 10 µm. The colors of the compounds are tuned from light yellow ( x = 0) to orange ( x = 0.1) and then to dark brown ( x = 0.5). X-ray photoelectron spectroscopy and UV–Vis absorption spectroscopy demonstrate the oxidation state of Cr to be + 6 and the change in color to be due to the metal-ligand charge transfer of Cr 6+ -O 2- .
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高影响因子
MOLECULES
·
2024
·Vol. 29
·期 18
·4477
·
IF 4.2
Fuhua Wei,Qin Zhang,Qinhui Ren,Hongliang Chen,Yutao Zhang,Zhao Liang
The Zn/Cr-MOFs/TiO2composites were synthesized using the solvothermal method. XRD, FTIR, and SEM techniques were utilized to characterize the Zn/Cr-MOFs/TiO2composites employed for simulating levofloxacin hydrochloride in wastewater. The impact of the mass of the Zn/Cr-MOFs/TiO2composite, concentration of levofloxacin hydrochloride, solution pH, and temperature on the adsorption performance was investigated. Experimental findings indicated that at pH 6, the maximum removal efficiency of levofloxacin hydrochloride by the Zn/Cr-MOFs/TiO2composite was achieved at 88.8%, with an adsorption capacity of 246.3 mg/g. To analyze the experimental data, both pseudo-first-order and pseudo-second-order kinetics models were applied, revealing that the pseudo-second-order model provided a better fit to the data. Additionally, Langmuir and Freundlich isotherm models were used to study equilibrium adsorption behavior and showed good agreement with both kinetic modeling and Langmuir isotherm analysis results. These observations suggest that monolayer adsorption predominates during the removal process of levofloxacin hydrochloride by Zn/Cr-MOFs/TiO2composites.
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高影响因子
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