Materials
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2022
·Vol. 15
·期 14
·4909
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IF 3.748
Yunquan Liu,Huimei Shan,Chunya Zeng,Hongbin Zhan,Yanyue Pang
Graphene oxide and chitosan microspheres modified with α–FeO(OH) (α–FeO(OH)/GOCS) are prepared and utilized to investigate the performance and mechanism for Cr(VI) removal from aqueous solutions and the possibility of Fe secondary pollution. Batch experiments were carried out to identify the effects of pH, mass, and volume ratio (m/v), coexisting ions, time (t), temperature (T), and Cr(VI) initial concentration (C0) on Cr(VI) removal, and to evaluate adsorption kinetics, equilibrium isotherm, and thermodynamics, as well as the possibility of Fe secondary pollution. The results showed that Cr(VI) adsorption increased withC0,t, andTbut decreased with increasing pH andm/v. Coexisting ions inhibited Cr(VI) adsorption, and this inhibition increased with increasing concentration. The influence degrees of anions and cations on the Cr(VI) adsorption in descending order were SO42−> PO42−> NO3−> Cl−and Ca2+> Mg2+> Mn2+, respectively. The equilibrium adsorption capacity of Cr(VI) was the highest at 24.16 mg/g, and the removal rate was 97.69% under pH = 3,m/v= 1.0 g/L,T= 298.15 K, andC0= 25 mg/L. Cr(VI) adsorption was well fitted to a pseudo-second-order kinetic model and was spontaneous and endothermic. The best fit of Cr(VI) adsorption with the Langmuir and Sips models indicated that it was a monolayer and heterogeneous adsorption. The fitted maximum adsorption capacity was 63.19 mg/g using the Sips model under 308.15 K. Cr(VI) removal mainly included electrostatic attraction between Cr(VI) oxyanions with surface Fe–OH2+, and the adsorbed Cr(VI) was partially reduced to Cr(III) and then precipitated on the surface. In addition, there was no Fe secondary pollution during Cr(VI) adsorption.Keywords:hydroxyl iron oxide;graphene oxide;chitosan;Cr(VI) adsorption
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ACS Applied Nano Materials
·
2022
·
IF 6.14
Tao Xian,Hongqin Li,Xiaofeng Sun,Yashan Huo,Lijing Di,Chenyang Sun,Hua Yang
The In2O3 nanoparticles were homogeneously attached on the BiOBr nanoplate surface to obtain S-scheme In2O3/BiOBr heterojunction photocatalysts by a hydrothermal route. The purity, crystal structure, chemical state, morphology, light absorption property, and photogenerated charge behavior of composites were investigated by XRD, SEM, TEM, HRTEM, XPS, UV–vis DRS, PL, ESR, and electrochemical tests. The removal of dyes (acid orange 7 (AO7), acid orange 10 (AO10), and rhodamine B (RhB)) and Cr(VI) was employed to evaluate the photocatalytic performance of In2O3/BiOBr composites irradiated by simulated sunlight. The results indicate that the photocatalytic performance of BiOBr can be remarkably promoted after the decoration of In2O3 nanoparticles, and the best photocatalytic activity was achieved over an 8% In2O3/BiOBr sample. The 8% In2O3/BiOBr sample also indicates outstanding synergistic photocatalytic performance for the removal of the heavy metal ion/dye mixture (AO7/Cr(VI) and RhB/Cr(VI)). It is found that the decoration of In2O3 nanoparticles can accelerate the transfer and separation of photoinduced electrons and holes in BiOBr nanoplates. The energy band structure, work function, and Fermi level of BiOBr and In2O3 were computed through the density functional theory calculation. Based on the above investigation, the photocatalytic mechanism of the S-scheme In2O3/BiOBr composite was discussed.
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JOURNAL OF FLUORESCENCE
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2022
·Vol. 32
·期 6
·2343-2350
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IF 2.525
Liu Tao,Zhang Shuai,Fan Xiaoyu,Yang Dou,Wang Min,Shao Xiaodong,Wang Shuhao,Yue Qiaoli
Carbon dots (CDs) were used to develop a sensitive sensing technique for detecting Cr(VI). CDs were made using a hydrothermal technique from citric acid and glutamic acid. These prepared CDs emitted blue fluorescence under excitation of 350 nm (λ em = 420 nm), and the fluorescence quantum yield was 48.41%. Transmission electron microscope was used to examine the morphology of the CDs, which had an average size of 2.21 ± 0.39 nm. The elementary composition and bonding structure of the CDs were conducted by XPS and FT-IR spectrum. Cr(VI) quenched the fluorescence of CDs through a static quenching effect and an inner filter effect, allowing Cr(VI) to be detected quantitatively. This approach was used to detect Cr(VI) in two samples of water, with the findings demonstrating that it is reliable and accurate. The fluorescence intensity change was linearly related to the concentration of Cr(VI) in the range from 0.5 to 400 μM, with the detection limit being 0.10 μM. This approach has the virtues of wide detection range, low cost and fast response. The strategy has a great application prospect for detecting Cr(VI) in practical samples.
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Small
·
2022
·Vol. 18
·期 35
·2201949
·
IF 15.153
Xiaoning Li,Meng Li,Quanyu Shi,Hongmin Guo,Lidong Wang,Xiaolin Guo,Zhijun Chen,Jonathan L. Sessler,Huining Xiao,Tony D. James
Heavy metal pollution has resulted in numerous environmental challenges. However, classic approaches, involving the use of solid adsorbents are subject to limitations, including the high energy consumption required for processing before and after use. Accordingly, strategies that facilitate the use of metal capture media that extends beyond waste remediation are attractive. Herein, a porous fluorescent aerogel (CPC aerogel) is constructed by immersing amino-based carbon dots (CDs-NH 2 ) into a polyethyleneimine (PEI)/carboxymethylated cellulose (CMC) aerogel network for the simultaneous detection and adsorption of Cr(VI). Adsorption experiments confirm that the CMC/PEI containing CDs-NH 2 aerogel (CPC aerogel) exhibits good Cr(VI) extraction capacity, and can reach a level that conforms with industrial water safety standards. In addition, the CPC aerogel can continuously detect and remove Cr(VI) at high flux. Following Cr(VI) absorption, the CPC aerogel may be vulcanized (MS x -CPC gel) and used for solar thermoelectric generation resulting in power generation. Additionally, the MS x -CPC gel can be used for solar steam generation and exhibits excellent evaporation rates of ≈1.31 kg m –2 h –1 under one sun irradiation. The results serve to underscore how materials designed for metal ion recognition and adsorption once exhausted can be exploited to provide materials for solar thermoelectric power generation and seawater desalination.
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Scientific Reports
·
2021
·Vol. 11
·期 1
·1-9
·
IF 4.38
Zhang Shujie,Zhang Yating,Fu Lisong,Jing Mengke
The application shell uses cellulose as a green and recyclable fiber material, which has great value in the field of water treatment environment. Varying factors, including pH value, dosage of CS, reaction time and original Cr(VI) ions and Cu(II) ions were studied to investigate the Cr(VI) and Cu(II) ions removal efficiency. The obtained shell trichlorocellulose has better permeability to copper ions, which is mainly due to the different oxide states of copper ions and chromium ions in a pH environment, which lead to different combinations. The price of shell cellulose neutralization is relatively low. Metal ions have better absorption properties. The kinetic and thermodynamic characteristics of the adsorption process of copper ions by chitosan yarns were discussed. The adsorption process of copper ions conformed to the quasi-second-order kinetic equation. It can be fitted by Langmuir isotherm. The adsorption of copper ions by the yarn is a spontaneous thermal reaction with both physical adsorption and chemical adsorption. Compared with chromium ions, chitosan fibers have better adsorption of copper ions, which is mainly because the amino groups in chitosan fibers can have good chelation with copper ions. SEM, FTIR, XRD were used to characterize the adsorption of copper ions by chitosan fibers, and the mechanism of the adsorption of metal ions by chitosan fibers was explored.
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MICROCHEMICAL JOURNAL
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2021
·
IF 4.821
Yueting Liao,Yaohai Zhang,Qiyang Zhao,Wei Xiang,Bining Jiao,Xuesu Su
Metal organic framework MIL-101(Cr) was successfully synthesized as a selective adsorbent by a facile self-assembly technique and combined with UPLC-MS/MS for enrichment and determination of neonicotinoids in fruit juices and tea beverages. Therein, MIL-101(Cr) was characterized by Fourier transform infrared spectrometry, scanning electron microscopy, X-ray diffraction, and N 2 adsorption–desorption isotherms. Box-Behnken design was applied to optimize the significant variables including the sorbent amount, pH of the matrix, eluant volume, extraction time and desorption time. The optimized conditions were sorbent amount of 20 mg, eluent volume of 1 mL, extraction time of 5 min and desorption time of 4 min. Under the optimized conditions, excellent sensitivity was achieved with the limit of detection of 0.0019–0.02 μg/L and limit of quantification of 0.0063–0.067 μg/L. Good linearity (R 2 ≥ 0.9988) was obtained within the range of 1–1000 μg/L, and the recovery was 71.04%-101.64% with relative standard deviations (RSDs) of 1.25%-8.82% in spiked samples. The inter- and intra-day RSDs were both<8.54%. The adsorption isotherms investigated for acetamiprid, thiacloprid, and imidacloprid pesticides better fitted with the Freundich adsorption isotherm with bimolecular adsorption capacity of 71.43, 68.49, and 50.38 mg/g, respectively. These results indicate that the nanocomposite is feasible for adsorption of the target analytes at trace amounts from fruit juices and tea beverages.
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Scientific Reports
·
2021
·Vol. 11
·期 1
·1-15
·
IF 4.38
Eltaweil Abdelazeem S.,El-Monaem Eman M. Abd,Mohy-Eldin Mohamed S.,Omer Ahmed M.
An efficient composite was constructed based on aminated chitosan (NH 2 Cs), attapulgite (ATP) clay and magnetic Fe 3 O 4 for adsorptive removal of Cr(VI) ions. The as-fabricated ATP@Fe 3 O 4 -NH 2 Cs composite was characterized by Fourier Transform Infrared Spectroscopy (FTIR), Thermal Gravimetric Analyzer (TGA), Scanning Electron Microscope (SEM), Zeta potential (ZP), Vibrating Sample Magnetometer (VSM), Brunauer–Emmett–Teller method (BET) and X-ray photoelectron spectroscope (XPS). A significant improve in the adsorption profile was established at pH 2 in the order of ATP@Fe 3 O 4 -NH 2 Cs(1:3) > ATP@Fe 3 O 4 -NH 2 Cs(1:1) > ATP@Fe 3 O 4 -NH 2 Cs(3:1) > Fe 3 O 4 -NH 2 Cs > ATP. The maximum removal (%) of Cr(VI) exceeded 94% within a short equilibrium time of 60 min. The adsorption process obeyed the pseudo 2nd order and followed the Langmuir isotherm model with a maximum monolayer adsorption capacity of 294.12 mg/g. In addition, thermodynamics studies elucidated that the adsorption process was spontaneous, randomness and endothermic process. Interestingly, the developed adsorbent retained respectable adsorption properties with acceptable removal efficiency exceeded 58% after ten sequential cycles of reuse. Besides, the results hypothesize that the adsorption process occurs via electrostatic interactions, reduction of Cr(VI) to Cr(III) and ion-exchanging. These findings substantiate that the ATP@Fe 3 O 4 -NH 2 Cs composite could be effectively applied as a reusable adsorbent for removing of Cr(VI) ions from aqueous solutions.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2021
·
IF 3.764
Ju Liu,Dandan Hao,Huiwen Sun,Yu Li,Jianlin Han,Bo Fu,Jiancheng Zhou
In this Article, a hybrid foam was fabricated through the integration of amine-functionalized Fe-MOF (MIL-101-NH2) into cellulosic matrix. The existence of enormous group linkages and ionic bonding interactions among the composite foam network leads to a uniform dispersion of MIL-101-NH2 and high affinity between the MOF and cellulose skeleton. As-prepared hybrid foams were utilized as photocatalysts to reduce toxic hexavalent chromium ions (Cr(VI)) under visible light. Optimal performance was observed over CM-1 (with a MIL-101-NH2 and nanocellulose mass ratio of 1:1). When compared to pure MOF nanoparticle counterparts, the CM-1 foam presented preferable and more efficient Cr(VI) removal performance. The reasons could be attributed to the hierarchal pore structure and uniform MOF loading. Moreover, the flexible foams could be easily separated from the solution and preserved more than 80% removal efficiency of Cr(VI) after 10 runs. This work would shed light on how to construct high-efficiency photocatalysts for environmental governance from sustainable materials.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2021
·
IF 7.312
Guanglai Mo,Linxi Wang,Jianhong Luo
It is a challenge to achieve efficient photocatalytic activity of pure MOFs. Herein, the defective NH 2 -MIL-125(Ti) with adjustable linker vacancy level was successfully created by thermal treatment. The band gaps of samples decreased and the more Ti-O clusters on the surface of the samples can be achieved as the time of thermal treatment increased from 0 to 500 min, both of which facilitated the photocatalytic activity for the reduction of Cr(VI). Moreover, the ligands from the surface to the inside of the samples were successively decarboxylated, resulting in the declined specific surface area and the increased proportion of mesoporous and the defect level. The moderate defect level in NH 2 -MIL-125(Ti) can be obtained as the time of thermal treatment was 300 min, which facilitated the separation of photogenerated charges, contributing to the highest photocatalytic activity for reduction of Cr(VI), which was 9.2 times than that of the initial MOFs. However, the excessive linker vacancy defect level in NH 2 -MIL-125(Ti) may result in the seriously affected crystal structure and the retarded separation of photogenerated charges.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Kairuo Zhu,Lili Chen,Njud S. Alharbi,Changlun Chen
Magnetic carbon materials promise distinct advantages in the decontamination of heavy metal ions. In this work, a novel interconnected hierarchical nickel-carbon (Ni@IHC) hybrid was synthesized by combining the solvothermal method with a one-step pyrolysis under argon atmosphere. Benefitting from 3D flower-like morphology, interconnected porous nanosheets, large surface area, and abundant Ni nanoparticles, Ni@IHC hybrids can remove Cr(VI) within 25 min by using formic acid (FA) as a reductant at 25 ℃. Furthermore, the experimental parameters that can affect the material catalytic performance such as initial Cr(VI) concentration, catalyst dosage, FA concentration, and temperature were also investigated in detail. It was found that highly dispersed Ni nanoparticles contributed significantly to the reduction process. More importantly, the embedded Ni nanoparticles favor fast separation by a magnet and were helpful for the recycles use. This Ni@IHC hybrid was obtained by a facile and easy scale-up method, resulting in the fast transformation of Cr(VI) into Cr(III).
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MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
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2021
·
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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Nano Energy
·
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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