ACS Sustainable Chemistry & Engineering
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2019
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IF 6.97
Minlin Mao,Jiang Deng,Tingting Yan,Junjie Shen,Jianping Zhang,Liyi Shi,Dengsong Zhang
During the design and construction of an efficient iron–nitrogen–carbon (Fe–N–C) electrocatalyst, it was difficult to avoid the formation of iron oxides along with the hierarchical carbon frameworks containing dispersed FeNx sites. As a result, a slow oxygen reduction reaction (ORR) occurred, making it difficult to improve the electrocatalytic property. Herein, we have successfully synthesized the Fe, N-doped hierarchically porous carbon architectures from FeTe-trapped ZIF-8 coated with polydopamine by heat treatment. During the pyrolysis process, the evaporation of tellurium could inhibit the formation of iron oxides, promote the formation of more FeNx active species, and facilitate the formation of mesoporous structure to accelerate mass transfer and increase the approachability of active species. The resulting Fe, N-doped porous carbon architectures possessed excellent ORR catalytic performance, and the half-wave potential was 10 mV more than that of the precious Pt/C catalysts. Besides, the obtained catalysts present a superb methanol tolerance and long-term durability compared to precious Pt/C catalysts in alkaline media. This work opens up new avenues for the construction of the uniformly dispersed FeNx sites catalysts for ORR.
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RSC Advances
·
2019
·Vol. 9
·期 70
·41022-41030
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IF 3.049
Feilong Dong,Qiufeng Lin,Cong Li,Tuqiao Zhang
Blue-green algae commonly bloom in fresh water in summer, producing extra- and intra-cellular algal organic matters, which are important precursors for disinfection byproduct (DBP) formation. In this study, we evaluated the effect of pre-oxidation with ferrate(VI) (FeO42−, Fe(VI)) on the characterization of intracellular organic matter (IOM) and extracellular organic matter (EOM). The results indicated that soluble microbial-like products of EOM and IOM decreased and humic acid-like products of IOM increased, which would influence the DBP formation in the subsequent chlorination step. Therefore, in this study, the effect of Fe(VI) pre-oxidation on the DBP formation from IOM and EOM with subsequent chlorination was also investigated. For Chlorella sp., EOM presented no significant change, and IOM presented a reduction of THMs (8.2%) after Fe(VI) oxidation at a dosage of 16 mg L−1. For P. limnetica, EOM and IOM both exhibited reduction of trihalomethanes (THMs) and chloral hydrate (CH) after Fe(VI) oxidation. Besides, THMs had the lowest concentration at pH 8.0 in all four solutions. Haloacetonitriles (HANs) and haloketones (HKs) showed slight changes with increasing pH values. Due to the frequent detection of bromide (Br−) in surface water, the effect of bromide existence on THM formation was also investigated. The results indicated that all brominated DBPs increased, and chlorinated DBPs decreased with the increase in bromide concentration. In addition, the bromine substitution factor (BSF) of Chlorella sp. and P. limnetica both increased with the increase in Br− concentration.
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ACS Biomaterials Science & Engineering
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2019
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IF 4.511
Sihui Chen,Yixian Wang,Mengxiao Zhong,Dahai Yu,Ce Wang,Xiaofeng Lu
In the past decade, nanomaterials-based artificial enzymes have emerged as a hot spot in the field of catalysis. However, it is a significant challenge to fabricate functional nanomaterials for multiple-enzyme mimetic activity. In this work, we have presented an efficient catalytic platform to mimic peroxidase, oxidase, and catalase-like activity by Fe3C decorated carbon nanofibers (Fe3C/C NFs). First, polyacrylonitrile nanofibers (PAN NFs) are prepared via an electrospinning technique. Next, an Fe(III)-tannic acid (TA) complex is formed on the surface of PAN NFs through a wet chemical reaction. Finally, Fe3C/C NFs are obtained from the carbonization of the PAN/Fe(III)-TA complex nanofibers. The prepared Fe3C/C NFs show an excellent triple-enzyme mimetic property including peroxidase-like, oxidase-like, and catalase-like activity, which is investigated thoroughly by the colorimetric experiment of the 3,3′,5,5′-tetramethyl benzidine oxidation and the degradation of H2O2. Thanks to the superior catalytic performance of Fe3C/C NFs for oxidase mimicking, a facile and colorimetric way to determine glutathione with a high sensitivity and favorable selectivity has been achieved. This work provides an efficient platform for multiple-enzyme mimicking, which may expand their promising applications in biosensing, biomedicine, and environmental technology.
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ACS Sustainable Chemistry & Engineering
·
2019
·
IF 6.97
Chen Wang,Zhongfang Li,Likai Wang,Xueliang Niu,Suwen Wang
Exploring the oxygen electrocatalysts with both high oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) performance is crucial to developing the rechargeable Zn–air batteries (ZABs). Herein, we prepared a bifunctional three-dimensional graphene-like iron-nitrogen doped oxygen electrocatalyst (3D Fe/N-G#4, polyacrylamide (PAM):NaCl = 1:4, mass ratio) by a facile synthesis with PAM and iron as precursors and NaCl as template. The NaCl template melted during the pyrolysis process, which could fabricate a stable 3D network structure in the precursors to form more mesopores, higher specific surface area, and more exposed active sites and prevent the loss of precursors. The low-cost and water-soluble PAM as the N precursor provided abundant N and dissolved adequately with NaCl solution. The Fe precursor coordinated with the N to form Fe-Nx active sites that were investigated by HR-TEM, XRD, XPS, and RDE techniques. The 3D Fe/N-G#4 exhibited excellent electrochemical activity with a high half-wave potential (0.852 V vs RHE) for ORR and a low overpotential (393 mV at 10 mA cm–2) for OER in the alkaline conditions. In addition, the homemade rechargeable ZAB based on the prepared 3D Fe/N-G#4 exhibits high power density (168.2 mW cm–2) and excellent discharge-charge cycling stability (over 60 h) at 20 mA cm–2. This work provides a cost-efficient, simple, and eco-friendly method to synthesize excellent bifunctional non-noble electrocatalysts for commercialization of ZABs.
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JOURNAL OF MOLECULAR LIQUIDS
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2019
·
IF 4.561
Hongwei Luo,Yaoyao Zhao,Dongqin He,Qing Ji,Ying Cheng,Daoyong Zhang,Xiangliang Pan
Fe@Fe 2 O 3 core-shell nanowire is a promising heterogeneous Fenton iron catalyst to degrade organic pollutants. So far, the roles of hydroxylamine (HA) in Fe@Fe 2 O 3 /HA system for pollutant degradation still remain unknown. In this study, the HA-facilitated degradation of rhodamine B (RhB) and p-nitrophenol (PNP) by Fe@Fe 2 O 3 was reported and the underlying mechanisms were explored. Results show that addition of HA significantly enhanced degradation of organic pollutants and a higher HA dosage caused a faster degradation rate . The degradation process was completely inhibited by scavengers, indicating the hydroxyl radical (HO ) from bulk solution dominated the reactions. HA in the Fe@Fe 2 O 3 /H 2 O 2 /HA system was highly efficient to promote the generation of HO by accelerating both the Fe 3+ /Fe 2+ cycle and the H 2 O 2 decomposition. Meanwhile, HA itself was rapidly decomposed along with the pollutants degradation. About 50.5% of RhB and 46.4% of PNP were mineralized in the presence of HA. The effective pH value for degradation was expanded from 4.0 to 5.0. The EE/O calculations demonstrate that a higher energy input for PNP was required than that for RhB. This study will shed lights on the reactivity of the Fe@Fe 2 O 3 /HA system and provide an alternative pathway for removal of organic contaminants.
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CHEMICAL ENGINEERING JOURNAL
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2019
·
IF 8.355
Xingdong Shi,Yitao Li,Zhi Zhang,Lei Sun,Yazhou Peng
The appearance of large amounts of antibiotics in drinking water and wastewater treatment plants has attracted extensive interest because of the potential resultant environmental and biological risks. Although the Fe(II)/peroxymonosulfate (PMS) system provides a feasible method for antibiotic degradation, the narrow pH range in which it operates and the resultant iron precipitation limit its use. In this study, protocatechuic acid (PCA) was introduced into the Fe(II)/PMS system to improve the system performance. Ciprofloxacin (CIP) was used as the probe reagent. Compared with the Fe(II)/PMS system, the Fe(II)/PCA/PMS system performed better for CIP degradation. This enhanced degradation was attributed mainly to the reduction and chelating ability of the PCA, which enhanced radical generation by accelerating the transformation from Fe(III) to Fe(II) and by forming the PCA-Fe chelate. The Fe(II)/PCA/PMS system also showed a superior degradation ability, even under alkaline conditions, because the PCA-Fe chelate protected iron from precipitation and released hydrogen ions continuously in the process. The electron paramagnetic resonance and alcohol-quenching tests indicated that sulfate and hydroxyl radicals existed in this system and two main CIP degradation pathways were proposed from the liquid chromatography-mass spectrometry results. This work aims to provide new ideas for refractory organics treatment.
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WATER RESEARCH
·
2019
·
IF 7.913
Ling Li,Cui Lai,Fanglong Huang,Min Cheng,Guangming Zeng,Danlian Huang,Bisheng Li,Shiyu Liu,MingMing Zhang,Lei Qin,Minfang Li,Jiangfan He,Yujin Zhang,Liang Chen
This study investigated the hydrogen peroxide (H 2 O 2 ) activation potential of Fe–Mn binary oxides modified bio-char (FeMn/bio-char) for the degradation of naphthalene , the dominant PAHs in drinking water . Results showed that FeMn/bio-char exhibited 80.7- and 2.18-times decomposition rates towards H 2 O 2 than that of pure bio-char and Fe–Mn binary oxides, respectively, and consequently the FeMn/bio-char/H 2 O 2 photo-Fenton system presented highest naphthalene removal efficiency. The enhanced catalytic activity could be ascribed to the synergistic effect of the combination of bio-char and Fe–Mn binary oxides, such as promoting the adsorption capacity towards contaminant, increasing concentration of persistent free radicals (PFRs) and introducing Fe–Mn binary oxides as new activator. According to the batch-scale experiments, FeMn/bio-char/H 2 O 2 photo-Fenton system could degrade naphthalene effectively at a wide pH ranges, and 82.2% of naphthalene was degraded under natural pH of 5.6 within 148 min. Free radicals quenching studies and electron spin resonance (ESR) analyses verified that the dominant free radical within FeMn/bio-char/H 2 O 2 photo-Fenton system was hydroxyl radical (•OH). According to the preliminary analysis, the generation of •OH were ascribed to the activation of H 2 O 2 by Fe (II), Mn (II) and PFRs on the catalyst surface. The mainly degradation intermediates of naphthalene were identified by GC-MS analysis. Consequently, the possible degradation pathways were proposed. Moreover, naphthalene degradation experiments were also conducted in river, tap water , industrial wastewater as well as medical wastewater, and the results indicated that the FeMn/bio-char/H 2 O 2 photo-Fenton system was effective in the treatment of naphthalene in natural waters. This study brings a valuable insight for the potential environmental applications of modified bio-char.
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CHEMICAL ENGINEERING JOURNAL
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2019
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IF 8.355
Lian Zhang,Yue Zhang,Xuyan Gao,Chunhua Xu
Recent studies showed that Fe(II) acts as the major electron donor when sulfidated zero-valent iron (S-ZVI) is used for reductive removal of pollutants. However, few studies have focused on the utilization efficiency and regeneration rate of Fe(II). In this work, the dynamic interaction between pH and S-ZVI for Cr(VI) removal and Fe(II) production was investigated at several pH levels. It was found that the maximum utilization efficiency and regeneration rate of Fe(II) was obtained at pH 5, which is consistent with the Cr(VI) removal by S-ZVI. To further study the role of Fe(II) in Cr(VI) reduction, an innovative binary correlation analysis between aqueous Cr(VI) and Fe(II) was applied with the addition of 1,10-phenanthroline as a way to control Fe(II) availability for Cr(VI) reduction. The analysis revealed that the Cr(VI) sequestration was initially controlled by Fe 0 /FeS and then by Fe(II), which accounts for the majority of the Cr(VI) sequestration. Additionally, the effects of several operational parameters (e.g., S/Fe ratio, S-ZVI dosage and initial concentration of Cr(VI)) on Cr(VI) removal were also evaluated and the results indicated that the removal of Cr(VI) exhibited a bimodal pattern with increasing S/Fe ratio, but followed a unimodal pattern with increase of S-ZVI dosage and chromium concentration. This study sheds additional insight into the dynamic interaction between pH and Fe(II), which is significant for further improving the efficiency of Fe(II) on contaminants.
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Journal of Materials Chemistry B
·
2019
·Vol. 7
·期 31
·4794-4800
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IF 5.047
Kun Ye,Linjie Wang,Hongwei Song,Xin Li,Xiangheng Niu
Alkaline phosphatase (ALP) is extensively used as a clinical biomarker because of its close relevance with a variety of diseases. Thus, exploring reliable and practical methods for ALP analysis is of great significance. In the present work, we explored MIL-53(Fe) as a bifunctional platform with pyrophosphate (PPi)-mediated peroxidase-like activity and oxidation-stimulated fluorescence switching for ALP sensing. The proposed MIL-53(Fe) could exhibit favorable peroxidase-mimicking activity to catalytically decompose H2O2 to hydroxyl radicals, which had strong oxidizing ability to oxidize the terephthalic acid bridging ligand, resulting in the oxidation-stimulated turn-on fluorescence of MIL-53(Fe) itself. Due to the strong coordination interaction between PPi and Fe3+, the former with a relatively large molecular structure was able to inhibit the catalytic activity of MIL-53(Fe) via capping active Fe3+ sites, leading to the suppression of its self-fluorescence response. When ALP was present, it could hydrolyze the PPi inhibitor and restore the dual functions of MIL-53(Fe) to provide fluorescence again. With the above principle, highly sensitive and selective determination of ALP with a linear scope of 2–80 U L−1 and a detection limit down to 0.7 U L−1 was achieved. The MIL-53(Fe) was also demonstrated to be very reliable in measuring the target in human serum, indicating its great promise as an integrated tool for ALP detection in clinical practice.
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CHEMOSPHERE
·
2019
·
IF 5.108
Rongji Cui,Suxia Ma,Jie Wang,Shujun Sun
The catalytic gas-phase H 2 O 2 oxidation of NO was achieved over Fe-based catalysts supported on montmorillonite K10, γ-alumina and ZSM-5. ESR tests illustrate that the three catalysts can catalyze decomposition of H 2 O 2 yielding highly reactive hydroxyl radicals , of which Fe/K10 has the fastest rate, followed by Fe/γ-alumina. Fe 3+ in Fe/K10 and Fe/γ-alumina show lower density of electron cloud due to a strong interaction between Fe 3+ and the support, which benefits the electron transfer from the H 2 O 2 to Fe 3+ , thus favoring the production of hydroxyl radicals. Fe species exist on the surface of Fe/K10 mainly in the form of Fe 2 O 3 , whereas Fe species of Fe/γ-alumina and Fe/ZSM-5 exist mainly in the form of Fe 3 O 4 , and it is found that Fe 2 O 3 is more active than Fe 3 O 4 in catalytic gas-phase H 2 O 2 oxidation of NO. Interestingly, Fe/ZSM-5 has the lowest efficiency in generating hydroxyl radicals, its NO removal efficiency is 90%, which is much higher than 47.5% for Fe/γ-alumina and 62.3% for Fe/K10. In-situ IR results suggested that Fe/ZSM-5 are dual functional in oxidation of NO, that is, whether both Fe ion sites and Brønsted acid sites collectively provide the catalytic functionality. In the meantime, a possible reaction mechanism on catalytic gas-phase H 2 O 2 oxidation of NO over Brønsted acid sites is proposed.
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MOLECULES
·
2019
·Vol. 24
·期 20
·3718
·
IF 3.06
Mao-Long Chen,Shu-Yang Zhou,Zhou Xu,Li Ding,Yun-Hui Cheng
MIL-100(Fe, Cr) and MIL-101(Cr) were synthesized by the hydrothermal method and applied to the adsorptions of five aromatic amines from aqueous solutions. These three metal-organic frameworks (MOFs) were well characterized by powder X-ray diffraction (PXRD), scanning electron microscope (SEM), transmission electron microscope (TEM), thermogravimetric analysis (TGA) and surface area analysis. The adsorption mechanism of three MOFs and the effects of the structures of MOFs on the adsorption of aromatic amines were discussed. The results show that the cavity system and suitable hydrogen bond acceptor were important factors for the adsorption for five aromatic amines of aniline, 1-naphthalamine, o-toluidine, 2-amino-4-nitrotoluene and 2-nitroaniline: (a) the saturated adsorption capacity of aniline, 1-naphthylamine and o-toluidine on MIL-100(Fe) were 52.0, 53.4 and 49.6 mg/g, respectively, which can be attributed to the intermolecular hydrogen bond interaction and cavity system diffusion. (b) The adsorption capacity of 2-nitroaniline and 2-amino-4-nitrotoluene on MIL-101(Cr) were 54.3 and 25.0 mg/g, respectively, which can be attributed to the more suitable pore size of MIL-101(Cr) than that of MIL-100(Fe, Cr). The MOFs of MIL-100(Fe) and MIL-101(Cr) can be potential materials for removing aromatic amines from aqueous solutions.Keywords:metal-organic framework;adsorption;aromatic amines;aniline;1-naphthalamine;o-toluidine;2-amino-4-nitrotoluene;2-nitroaniline
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JOURNAL OF FLUORESCENCE
·
2019
·Vol. 29
·期 3
·769-777
·
IF 1.913
Luo Kuan,Jiang Xinyu
Nitrogen-sulfur co-doped carbon quantum dots (N, S-CQDs) with good photoluminescence properties were prepared by hydrothermal method using citric acid (CA) and methionine (Met) as precursors. Co-doping with N and S facilitates the electron transfer rate and coordination interaction between N,S-CQDs and Fe(III) ions which acts as a quencher of fluorescence. Based on a simple redox principle, a highly sensitive and selective method for the detection of ascorbic acid (AA) and H 2 O 2 was successfully developed. The calibration curves obtained are linear for the current versus AA and H 2 O 2 concentration over the range 50–500 μM and 10–140 μM, respectively. And the detection limits for AA and H 2 O 2 are 4.2 μM and 1.9 μM, respectively. The quantitative analysis of AA and H 2 O 2 in various juices and H 2 O 2 disinfectant with Fe 3+ /CQDs or Fe 2+ /CQDs gave the recoveries of 87.8%–117.5% and 99.2%–106.4% with relative standard deviations ( RSD ) of 1.6–5.1% and 1.7–3.1%, respectively, showing satisfactory results for the determination of AA and H 2 O 2 in actual application. The proposed strategy may provide a new pathway to developing inexpensive and sensitive way for the detection of various redox reaction–involved system.
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