Analytical Methods
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2022
·Vol. 14
·期 25
·2541-2548
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IF 3.532
Lixia Su,Yonghuan Su,Bingqian Liu
A new ratiometric electrochemical strategy for immobilization-free detection of Escherichia coli (E. coli) was constructed by using a capture DNA-polyaniline/copper ferrite nanoparticles/graphene oxide (cDNA-PANI/CuFe2O4/GO) composite as capture probes, which has a high specific surface area and good magnetic properties. Then trigger DNA/Au nanoparticles (tDNA/Au NPs) were used as signal amplification labels, and Pt (IV) and Fe (III) were chosen as the signal probes. In the presence of targets, the sandwich format among cDNA-PANI/CuFe2O4/GO, E. coli and auxiliary DNA (aDNA) was realized by using the aptamer recognition system. Then, the tDNA/Au binding could be anchored on the sandwich format due to the principle of base complementation between unpaired aDNA and tDNA. And the unbounded tDNA of tDNA/Au NPs could bind an amount of Pt (IV). After separation using a magnet, a handful of unbound Pt (IV) which remained in the supernatant reacted with a large number of Fe (III) ions, leading to a markedly increased IFe(III)/IPt(IV) value. Oppositely, the sandwich format could not appear in the absence of targets, and even the tDNA/Au could not be immobilized on it. So, the redox reaction between a large amount of Pt (IV) residue in the supernatant and Fe (III) was significantly successful, causing a low IFe(III)/IPt(IV) value. Under optimal conditions, we found that IFe(III)/IPt(IV) was linearly related to the logarithmic E. coli concentration with a low limit of detection (1.862 × 103 cfu mL−1). This devised ratiometric electrochemical method may develop into a powerful and effective means for the detection of E. coli in real samples, which may also be developed as a universal tool for another microorganism.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2022
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IF 4.831
Ling Wu,Feng Li,Haidong Yu,Luping Shen,Mingxi Wang
Spectrophotometry is an economic and rapid method for detecting oxalic acid (OA), while the reported methods have some drawbacks, such as narrow linear range, long response time, delicate operation and required expensive reagents. Herein, we found that the as-synthesized Fe(III)-sulfosalicylate (FeSSA) could be used as an efficient colorimetric chemosensor to detect OA, and the established FeSSA-based fading spectrophotometry showed prominent advantages over the existing ones in detecting OA. The as-established method has wider linear range of 0.80–160 mg/L with regression coefficient ≥ 0.999, while the widest linear range is just 2.7–54 mg/L among the reported ones. Moreover, the method has low limit of detection (0.74 mg/L), extremely fast response (several seconds), satisfactory selectivity, high accuracy and precision. Most importantly, its reliability was further verified by employing it to determine OA concentration during the degradation process of organic pollutants. The measured OA concentration at any time interval was perfectly consistent with those determined by the well-recognized high performance liquid chromatography (HPLC). These confirmed that the FeSSA-based fading spectrophotometry is an efficient, simple, fast, accurate and economic method to determine OA in a wide concentration range.
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RSC Advances
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2022
·Vol. 12
·期 27
·17237-17248
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IF 4.036
Dongqing Feng,Jianxin Shou,Sen Guo,Mengna Ya,Jianfa Li,Huaping Dong,Yimin Li
Activation of hydrogen peroxide (H2O2) with biochar is a sustainable and low-cost approach for advanced oxidation of organic pollutants, but faces the challenge of a low yield of hydroxyl radical (˙OH). Herein, we hypothesize that the activation efficiency of H2O2 can be enhanced through co-catalysis of trace dissolved iron (Fe) with biochar. Two biochar samples derived from different feedstock, namely LB from liquor-making residue and WB from wood sawdust, were tested in the co-catalytic systems using trace Fe(III) (0.3 mg L−1). The cumulative ˙OH production in [Fe(III) + LB]/H2O2 was measured to be 3.28 times that in LB/H2O2, while the cumulative ˙OH production in [Fe(III) + WB]/H2O2 was 11.9 times that in WB/H2O2. No extra consumption of H2O2 was observed in LB/H2O2 or WB/H2O2 after addition of trace Fe(III). Consequently, the reaction rate constants (kobs) for oxidation of pollutants (2,4-dichlorophenoxyacetic acid and sulfamethazine) were enhanced by 3.13–9.16 times. Other iron species including dissolved Fe(II) and iron minerals showed a similar effect on catalyzing 2,4-D oxidation by biochar/H2O2. The interactions involved in adsorption and reduction of Fe(III) by biochar in which the defects acted as electron donors and oxygen-containing functional groups bridged the electron transfer. The fast regeneration of Fe(II) in the co-catalytic system resulted in the sustainable ˙OH production, thus the efficient oxidation of pollutants comparable to other advanced oxidation processes was achieved by using dissolved iron at a concentration as low as the concentration that can be found in natural water.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
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2022
·Vol. 414
·期 26
·7741-7751
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IF 4.478
Liu Yuqian,Hu Xianyun,Liang Fangyuan,Cao Yajing
Exploring sensors based on Förster resonance energy transfer (FRET) systems enables the continuous development of biological sensing technologies. Herein, we report the construction of a FRET sensor with dual-emissive quantum dots (QDs) and meso -tetra(4-sulfonatophenyl) porphine (TSPP). The sensor is composed of mesial green-emissive QDs with a thick silica shell (gQD@SiO 2 ) and circumjacent blue-emissive QDs coated with ultra-thin silica spacer, on which is linked TSPP (bQD@SiO 2 -TSPP). The gQD@SiO 2 endows the sensor with a fluorescent background. Due to the ultra-thin silica spacing, coupled with the superior resonance effect of bQD fluorescence and the Soret-band absorption of TSPP, the FRET efficiency is highly sensitive to the chelation state of TSPP. Relying on the absorbance transition of TSPP complexed with Fe(III), the FRET sensor is applied for ultra-sensitive Fe(III) detection. In aqueous solution, the sensor is demonstrated to linearly detect Fe(III) in the range of 0–1 μM, with a limit of detection (LOD) of 40 nM. More importantly, reliable Fe(III) detection can be achieved via the specific complexation of Fe(III) by TSPP and the ratiometric fluorescent response. As such, the inter-/intra-day precisions in standard samples, as well as the recovery rate in biological matrices, are fully validated. The excellent analytical performance, in combination with the excellent biocompatibility of the FRET sensor, allows semi-quantitative Fe(III) imaging in living cells. Graphical abstract
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CHEMICAL GEOLOGY
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2021
·
IF 4.015
ChunYan Luo,ShuaiLong Wen,YueHan Lu,JiaRu Dai,YingXun Du
The coprecipitation of dissolved organic matter (DOM) and phosphate with Fe(III) at the sediment-water interface plays an important role in the biogeochemical cycle of organic carbon (OC) and phosphorus (P) in aquatic ecosystems . However, studies remain limited towards understanding the strength of ternary DOM-phosphate-Fe(III) coprecipitation in sequestering OC and P. Here, we investigated the behaviors of humic acid (HA) and phosphate during their coprecipitation with Fe(III) and compared the coprecipitation behaviors with those during the adsorption process. The results showed that the coprecipitation of HA and phosphate with Fe(III) enhanced as pH decreased or initial Fe(III) concentrations increased. The presence of phosphate had a moderate inhibition effect on HA coprecipitation, leading to 3%–37% of reduction in precipitated HA. Changes in optical properties of DOM (i.e., SUVA 254 , E 2 /E 3 , and fluorescent components) showed that macromolecular, aromatic molecules preferentially coprecipitated, and this selectivity pattern was not influenced by the presence of phosphate. Compared to the adsorption of HA and phosphate to goethite , coprecipitation with Fe(III) displayed stronger binding ability, sequestering more than10 times of HA and phosphate, and was more efficient in sequestering protein-like compounds. The inhibitory effect of phosphate on HA sequestration was weaker during coprecipitation than during adsorption. Moreover, coprecipitation led to a lower degree of compositional fractionation of HA than adsorption, which may be explained by that inclusion, an important pathway for coprecipitation, has low selectivity for chemical compositions. Collectively, our results demonstrate that coprecipitation plays a crucial role in sequestering both OC and P in aquatic systems, arguing that the formation of ternary OC-Fe-P coprecipitates may be an important pathway for sequestering OC and P over a long term and reducing the internal loading of P in eutrophic lakes.
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MICROPOROUS AND MESOPOROUS MATERIALS
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2021
·
IF 5.455
Mengmeng Zhang,Jiaying Lou,Rui Xu,Peng Li,Yunfei Sha,Hui Zhang,Yu Jia,Zhenxia Chen,Da Wu,Yun Ling,Yaming Zhou
Metal-organic frameworks (MOFs) featuring a fcu-type net based on 12-connected [Zr 6 (μ 3 -O) 4 (μ 3 -OH) 4 ] cluster have received considerable interest for the fundamental investigation of structure-property relationships in a wide range of catalytic reactions . In this work, the bipyridine (bpy) chelate group was introduced into the fcu-type framework of UiO-67, giving UiO-67bpy as the catalyst support. Then, FeCl 3 was post-synthetically anchored to the bpy group, resulting into the isolation of FeCl 3 /UiO-67bpy. Catalyzed hydrolysis of 5-hydroxylmethoxyfurfural (HMF) into levulinic acid (LA) was then explored and revealed that it can efficiently and selectively catalytic convert HMF into LA, which is superior to that of FeCl 3 /UiO-67 where FeCl 3 is encapsulated in the cage of UiO-67 and dispersed on the pore surface. The recyclability studies further confirmed the importance of anchored FeCl 3 where there is no significant decrease in catalytic activity as compared with that of FeCl 3 /UiO-67. Taking the detailed textural porosity and catalytic results of isomorphous structures in consideration, our studies revealed that narrowing the pore size with anchored FeCl 3 on the skeleton of the fcu-type Zr-MOF rather than encapsulating FeCl 3 inside the cage is more favored for the rehydration reaction of HMF to LA.
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ENVIRONMENTAL RESEARCH
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2020
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IF 5.715
Yun Bai,Doudou Wu,Wei Wang,Pei Chen,Fatang Tan,Xinyun Wang,Xueliang Qiao,Po Keung Wong
Herein, the application of organic acids as chelating agent , including citric acid (CA), tartaric acid (TA), oxalic acid (OA) and ethylenediaminetetraacetic acid (EDTA), to enhance the degradation performance of MgO 2 /Fe(III) system was investigated in the terms of chelating agent dosage, Fe(III) dosage, reaction temperature, initial solution pH and inorganic anion. When the molar ratio of MgO 2 /Fe(III)/chelating agent was 1 : 0.7 : 0.3, the degradation efficiencies of Rhodamine B (RhB) increased from 6.7% (without chelating agent) to 42.3%, 98.5%, 48.9% and 25.8% within 30 min for CA, TA, OA, and EDTA, respectively. The promotion effect was mainly attributed to the chelation between chelating agents and Fe(III), rather than the acidification of chelating agents. The pseudo-first-order kinetic model well fitted RhB degradation in MgO 2 /Fe(III)/TA system, and the kinetic rate constant reached up to 0.295 min −1 . Hydroxyl radical was confirmed to be the dominant active species to degrade organics in the MgO 2 /Fe(III)/TA system. Notably, the degradation system could work in a broad pH (3–11) and temperature (5–35 °C) range. Moreover, the MgO 2 /Fe(III)/TA system can also effectively degrade methylene blue , tetracycline and bisphenol A. This work provided a new, efficient and environmentally-friendly Fenton-like system for stubborn contaminant treatment.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2020
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IF 7.489
Zhengfeng Shen,Feifei Li,Jiangrui Lu,Zhidan Wang,Rui Li,Xiaochao Zhang,Changming Zhang,Yawen Wang,Yunfang Wang,Zhiping Lv,Jianxin Liu,Caimei Fan
Photocatalytic nitrogen fixation has been considered to be a safe, green, eco-friendly, and sustainable technology. However, photoinduced activation of inert dinitrogen is an important factor hindering the development of this technology. Herein, in-situ Fe 3+ doped flower-like BiOCl with highly active sites exposure was prepared by a solvent thermal method, which has excellent performance of N 2 photofixation. Compared with virgin BiOCl with no nitrogen fixation activity, Fe-BiOCl reached 30 μmol·L −1 ·h −1 ammonia evolution rate under simulated sunlight without any sacrificial reagent. Characterization results demonstrated that the enhancement of N 2 photofixation capacity was mainly attributed to the in-situ doped Fe 3+ in BiOCl, the doped Fe 3+ not only acts as a reaction center for N 2 activation also as an “electron transfer bridge” trapping and migrating electrons from BiOCl to N 2 molecules. Furthermore, the transformation of crystal facets from virgin BiOCl (0 0 1) to Fe-BiOCl (1 1 0) and (1 0 2) is more conducive for the exposure and accessibility of iron reactive sites. This work developed a potential strategy by in-situ introducing Fe 3+ active sites in BiOCl semiconductor substrate, which establishes a good basis for the application of semiconductor catalysts in nitrogen fixation.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2020
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IF 5.774
Weike Zhao,Bo Zhou
In recent years, multi-walled carbon nanotubes (CNTs), which are emerging nanocatalysts, have received much attention in advanced oxidation processes. CNTs were introduced into H 2 O 2 /Fe(III) Fenton-like process to enhance the degradation of bisphenol A (BPA) in this study. The results of the study suggests that CNTs could effectively promote electron transfer from H 2 O 2 to Fe(III) and directly reduce Fe(III) to Fe(II) to accelerate Fe(III)/Fe(II) cycles, in which carbonyl groups and structural defects of CNTs were identified as the major active sites via SEM, Raman, XRD, FTIR and XPS analyses. It was revealed that hydroxyl radical (·OH) majorly contributed to the degradation of BPA, and the generation efficiency of ·OH was significantly increased by 3.2 times with the addition of CNTs. Also, nine intermediate products were identified, and the possible degradation pathways of BPA were proposed through the density functional theory (DFT) calculations and HPLC-MS/MS analysis. The ecotoxicity evaluation of BPA demonstrates that the oxidative degradation of BPA in CNTs/H 2 O 2 /Fe(III) system could effectively reduce its environmental risk. The critical experimental parameters including the dosage of Fe(III), H 2 O 2 , CNTs, initial pH and various anions (Cl − , HCO 3 – , SO 4 2− ) were investigated, and the reusability experiments indicate that CNTs maintained high stability and reusability during the reaction.
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SEPARATION SCIENCE AND TECHNOLOGY
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2021
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IF 2.475
Xuekai Zhang,Kanggen Zhou,Qingyuan Lei,Yan Xing,Changhong Peng,Wei Chen
A new approach was developed using NaH2PO4 as the stripping agent for Fe stripping from Fe-loaded Aliquat 336 during rare-earth elements recovery from red mud leachate. Owing to the strong coordination between Fe3+ and H2PO4‒, Fe mainly exists as FeH2PO42+ at [H2PO4‒] higher than 0.5 M, which can be readily stripped. The results showed a maximum Fe stripping efficiency of 95.5% under optimal condition. Moreover, the extraction capacity of the extractant after stripping was comparable to that of fresh extractant, and decreased only by 2% after 6 cycles, indicating the robustness of this approach for Fe stripping and extractant regeneration.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2020
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IF 7.489
Jiuli Chang,Liming Chen,Shiqi Zang,Yifan Wang,Dapeng Wu,Fang Xu,Kai Jiang,Zhiyong Gao
A facile and efficient oxygen evolution reaction (OER) catalytic system was constructed based on interconnected Ni(OH) 2 nanosheets arrays electrode and Fe(III) containing alkali electrolyte. The partial deposition of Fe(III) onto Ni(OH) 2 with heterostructure obviously enhanced the OER current density and reduced the overpotential, and the Fe(III) cations in electrolyte also furnished positive contribution to the catalytic reaction, the synergy between Ni(OH) 2 electrode and Fe(III) cations in electrolyte therefore substantially improved the OER catalytic efficiency with low overpotential (285 mV at current density of 50 mA cm −2 ) and obviously enhanced current density (391 mA cm −2 at 1.8 V). The current work expands our understanding on the effect of Fe(III) cations in electrolyte to OER efficiency of Ni based catalyst, and opens up a cost-effective and practical avenue to enhance the OER catalytic efficiency by introducing metal cations in alkali electrolyte.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2019
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IF 2.931
Aiwen Yu,Yiping Tang,Kai Li,Jinwei Gao,Yuhui Zheng,Zhi Zeng
Fluorescence has been well documented and the optical feature of carbon dots generates considerable interests. Here the nitrogen-doped carbon dots with a relative quantum yield of 25% have been prepared. It displays stable blue emission based on the excitation at 355 nm. The carbon nanomaterial is highly dispersible in aqueous solution and can be employed as an effective optical probe for label-free detection of Fe 3+ (0.87 μM) via a switched off change. Additionally, such sensing nanoplatform can be recovered in the presence of pyrophosphate (PPi) and an “off-on” process has been identified. It is expected that this on-off-on strategy will allow new possibilities for developing efficient sensors in industrial fields.
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危险品化学品经营许可证（带存储）