JOURNAL OF POROUS MATERIALS
·
2019
·Vol. 26
·期 6
·1839-1850
·
IF 1.947
He Lei,Zhang Yaqin,Zheng Yane,Jia Qingming,Shan Shaoyun,Dong Yanan
An effective catalyst of MIL-101(Fe)/TiO 2 composite was synthesized by solvothermal method. The resultant MIL-101(Fe)/TiO 2 was used for advanced oxidation degradation of tetracycline (TC) for the first time. The results indicated that the MIL-101(Fe)/TiO 2 showed higher TC degradation efficiency than pure MIL-101(Fe) or TiO 2 with the persulfate. Using 1 g L −1 MIL-101(Fe)/TiO 2 and persulfate at pH 7, 90.15% degradation rate was achieved under xenon lamp irradiation in 5 min for 20 mg L −1 TC. TiO 2 introduced in the composite played an important role in the degradation process, in which TiO 2 had a synergetic effect with Fe 3+ to generate Fe 2+ , Ti 3+ and radicals. Fe 2+ reacted with persulfate to produce Fe 3+ and a number of · OH to degrade TC. This reaction process was so fast that MIL-101(Fe)/TiO 2 with persulfate could degrade TC fairly rapidly. A novel TiO 2 -based metal–organic frameworks (MOFs) composite was more efficient for degrading pharmaceutical wastewater.
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Nano Energy
·
2019
·
IF 15.548
Biwei Wang,Jinxiang Zou,Xiaochen Shen,Yuchi Yang,Guangzhi Hu,Wei Li,Zhenmeng Peng,Dustin Banham,Angang Dong,Dongyuan Zhao
Iron-nitrogen-carbon (Fe-N-C) materials featuring Fe-N 4 moieties are promising candidates to replace commercial Pt/C catalysts for the oxygen reduction reaction (ORR). Here we report a novel Mn-Fe-N/S@mC catalyst comprising atomically dispersed Fe-N 4 sites and a trace amount of Mn-N 2 S 2 sites, which are homogeneously anchored on an ordered mesoporous graphitic carbon framework. This dual-metal catalyst is realized based on the chemical conversion of self-assembled Mn 0.43 Fe 2.57 O 4 nanocrystal supracrystals, with the dual metal sites and the graphitic framework derived from nanocrystal cores and the associated capping ligands, respectively. When evaluated as electrocatalysts for the ORR, Mn-Fe-N/S@mC exhibits excellent catalytic activity in alkaline media , outperforming conventional Pt/C and most non-precious-metal catalysts reported previously. Notably, the synergistic effect of having Fe and Mn together improves the catalytic activity by a factor of ~ 5. To better understand the high efficiency of Mn doping in enhancing the activity of Fe-N 4 sites, density functional theory calculations were carried out, revealing that the synergistic interaction between the dual metal sites reduces the *OH reduction energy barrier during the oxygen reduction pathway.
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2019
·
IF 5.589
Rong Chen,Hui Liu,Peng Zhang,Lei Zhao,Kang Ding,Songhu Yuan
Groundwater table fluctuation during natural and anthropogenic processes can facilitate the interaction between oxygen (O 2 ) from the unsaturated zone and ferrous iron (Fe 2+ ) from the saturated zone. In light of previous findings that Fe(III)-reducing bacteria can be killed by the reactive oxidants produced from Fe 2+ oxidation under static oxic conditions, we hypothesize that Fe(III)-reducing bacteria will be attenuated during groundwater table fluctuations. To test this hypothesis, this study explored the variations of cell numbers of Shewanella oneidensis strain MR-1 (MR-1), a typical strain of Fe(III)-reducing bacteria, together with dissolved oxygen (DO) and Fe 2+ , at different points during controlled groundwater table fluctuations in a sand column. The results showed that, during the rise of the water table, O 2 in the pore air was entrapped by the deoxygenated groundwater, and Fe 2+ in the groundwater was oxidized by the entrapped O 2 . In this process, 1.40–2.42 orders of magnitude of viable MR-1 cells were killed at different points in the column. Further investigation proposed that the death of MR-1 is caused by the production of intracellular reactive oxidants, such as O 2 • − and OH•, from the oxidation of adsorbed/absorbed Fe 2+ instead of by bulk reactive oxidants, such as OH• and Fe(IV), produced from the oxidation of aqueous Fe 2+ . The findings here provide new insights for Fe biogeochemical cycling in the redox-dynamic zone.
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CATALYSIS TODAY
·
2018
·
IF 4.667
Yuexin Peng,Ling Zhang,Yiwen Jiang,Shichao Han,Qiuyan Zhu,Xiangju Meng,Feng-Shou Xiao
Catalytic combustion is considered as an efficient and economic technology to remove VOCs, and Al-ZSM-5 zeolite supported palladium catalysts (Pd/Al-ZSM-5) with good performances in this kind of reactions have been reported. In this work, it is found that Fe-ZSM-5 supported palladium catalyst (Pd/Fe-ZSM-5) exhibit higher catalytic activity in toluene combustion than the Pd/Al-ZSM-5, which is strongly related to more Pd 0 active species and higher concentration of absorbed oxygen species of Pd/Fe-ZSM-5 than those of Pd/Al-ZSM-5. More importantly, Pd/Fe-ZSM-5 has a good catalyst life and water-resistant ability, which should be potentially significant for practical applications in environment protection.
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GEOCHIMICA ET COSMOCHIMICA ACTA
·
2018
·
IF 4.69
Tongxu Liu,Dandan Chen,Xiaobo Luo,Xiaomin Li,Fangbai Li
Redox reactions between iron and nitrogen drive the global biogeochemical cycles of these two elements and, concomitantly, change the fate of nutrients in and the mineralogy of the cycles. The microbially mediated NO 3 − -reducing Fe(II) oxidation process (NRFO) plays a key role in Fe/N interactions under neutral-anoxic conditions. Microbially mediated NRFO was considered a biological process, yet recently it has been documented that chemical mechanisms are also at play. However, the relative contributions of biological processes and chemical processes to Fe(II) oxidation remain largely unquantified owing to the co-occurrence of the reactions. Herein, the kinetics and secondary minerals of microbially mediated NRFO by Pseudogulbenkiania sp. strain 2002 and Acidovorax sp. strain BoFeN1 were investigated with acetate as electron donor unless otherwise stated. The results of Cells + NO 3 − suggested the two strains could biologically reduce NO 3 − to NO 3 − /NO x /N 2 O/N 2 and concomitantly oxidize acetate and result in cell growth. Fe(II) oxidation and NO 3 − reduction occurred simultaneously in the presence of Fe(II) (Cells + Fe(II) + NO 3 − ). For strain BoFeN1, the presence of Fe(II) slightly enhanced the NO 3 − reduction, acetate consumption, and cell growth, all of which were substantially retarded by Fe(II) for strain 2002. When compared with the microbial nitrite reduction, the relatively higher rate of chemical reaction between NO 2 − and dissolved Fe(II) confirmed the occurrence of chemodenitrification in the microbially mediated NRFO processes. After 5 days’ incubation, no green rust was observed, and lepidocrocite , goethite , and magnetite were observed with the Cells + Fe(II) + NO 3 − treatment, but only goethite was found with the Fe(II) + NO 2 − . The spectra for the EPSs + Fe(II) treatment suggested that the oxidized c -Cyts in the EPSs could oxidize Fe(II), which show the theoretical capability of taking electrons from Fe(II) into the cells via c -Cyts. A brief model was established by combining the verified reactions of (1) biological reduction of NO 3 − to NO 2 − /NO x /N 2 O/N 2 , (2) Fe(II) oxidation by NO 2 − , and (3) Fe(II) oxidation by c -Cyts in EPSs. Based on the model, the rate constant of Fe(II) oxidation by c -Cyts in EPSs was derived. For nitrite reduction, the relative contribution of biological processes to the nitrite reduction was higher than that of chemodenitrification. For Fe(II) oxidation, the relative contribution of the chemical process via nitrite to Fe(II) oxidation was higher than that of biological processes. These findings provide a quantitative interpretation of the chemodenitrification and biological reactions in the microbially mediated NRFO processes, which could assist the mechanistic understanding of the global biogeochemical cycles of iron and nitrogen in subsurface environments.
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2018
·
IF 4.61
Xiaofei Li,Wenjing Zhang,Yunqi Qin,Tianyi Ma,Jingjing Zhou,Shanghai Du
To investigate the effect of different colloids on Fe migration in saturated porous media under different hydrochemical and hydrodynamic conditions, experiments were performed using colloidal silicon (inorganic) and colloidal humic acid (HA, organic), which are representative of the colloids in groundwater. Transport of Fe with and without colloid was investigated by column experiments using various porous media, colloid concentrations, ionic strengths (ISs), cation valences, and flow rates. The results show that colloidal silicon promotes and colloidal HA inhibits Fe transport, which is mainly because of their different bonding ratio, bonding modes with Fe and opposite surface charges between Fe–colloidal silicon and Fe–colloidal HA. Almost 100% of HA binds to Fe through the deprotonated functional groups, whereas only 13.3% of colloidal silicon binds to Fe, which is by electrostatic forces. Cotransport is also dependent on the hydrochemical and hydrodynamic conditions. For the Fe–colloidal silicon system, increasing the colloid concentration and flow rate, and decreasing the IS enhances Fe transport. Compared with colloidal silicon concentration = 10 mg/L, flow rate = 0.25 mL/min, and IS = 0.05 with CaCl 2 , a higher colloidal silicon concentration (20 mg/L), a higher flow rate (0.50 mL/min), and a lower IS (<0.0005 M) increase Fe recovery by 1.69%, 94.49% and 38.92%, respectively. Fe migration is also different in different porous media. For the Fe–colloidal HA system, Fe recovery decreases by 81.46% as the colloidal HA concentration increases from 0 to 20 mg/L. The type of porous medium and flow rate conditions have the same effects on Fe–colloidal HA transport as for colloidal silicon, although the electrical conditions have the opposite effect. With increasing IS, Fe–colloidal HA transport is enhanced because of competitive adsorption of the cations and Fe to colloidal HA and the porous medium.
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DALTON TRANSACTIONS
·
2019
·Vol. 48
·期 32
·12186-12192
·
IF 4.052
Jiang-Yan Xue,Fei-Long Li,Zhong-Yin Zhao,Cong Li,Chun-Yan Ni,Hong-Wei Gu,Pierre Braunstein,Xiao-Qing Huang,Jian-Ping Lang
The development of bifunctional non-noble metal electrocatalysts demonstrating high activity and stability for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is of great significance for renewable and clean energy. In this work, we report hierarchically structured integrated Fe–MoS2/Ni3S2/NF (NF = nickel foam) materials prepared by a facile in situ solvothermal method, and among them, the Fe-doped MoS2 was assembled into spine-like nanorods. The optimized electrocatalyst (denoted as Fe–MoS2/Ni3S2/NF-2) demonstrated excellent activity and durability for performing the HER and OER in an alkaline electrolyte (pH = 14) with low overpotentials of 130.6 mV and 256 mV (vs. RHE) at a current density of 10 mA cm−2, as well as no significant loss in catalytic performance even after 2000 cyclic voltammetry (CV) cycles. An outstanding durability of 180 h could be achieved for OER. The overall water splitting made up of the two-electrode system with Fe–MoS2/Ni3S2/NF-2 as both the anode and the cathode required a voltage of only 1.61 V to drive a current density of 10 mA cm−2 along with an outstanding long-term stability of 20 h, displaying its great potential for application in water splitting. The effective construction of multi-component synergistic structures shows a good pathway for high-performance electrocatalysis and energy storage.
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RSC Advances
·
2015
·Vol. 5
·期 83
·68200-68208
·
IF 3.84
Yuezhong Wen,Ying Liang,Chensi Shen,Hongkai Wang,Dongmei Fu,Hongyu Wang
A green efficient strategy for the combination of biodegradation and adsorption methods is urgently desired nowadays to degrade dyes in an economical and effective way. In this study, a kind of novel, environmentally friendly and efficient hybrid for the fungus and chitosan–Fe membrane has been fabricated by the alginate approach. Myrothecium verrucaria I-5 and C-1, deuteromycete fungi capable of producing laccase to degrade dyes, have been used. It is found that the chitosan–Fe membrane can excellently immobilize the fungi mycelia and enzyme, and after the immobilization, the fungi and enzyme still maintain a high activity after the dye decolorization. Also, the immobilized fungi membranes have been proved to have a high efficiency for dye decolorization. Simultaneously, the decolorization ability of the crude enzymes, which are extracted from I-5 and C-1 medium, and the decolorization ability of chitosan–Fe membrane are also investigated, respectively. The results demonstrate that the dyes can be removed by the fungi and the membrane synergistically. In addition, different kinds of dyes are successfully removed with chitosan–Fe immobilized fungi membranes. These results demonstrate that dyes are first adsorbed on the chitosan–Fe membrane, decreasing the toxicity to the fungus, and then bio-degraded by the laccase produced from the fungi on the membrane.
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ACS Catalysis
·
2015
·
IF 9.312
Dengke Wang,Mengtao Wang,Zhaohui Li
Phenol is one of the most important chemicals in industry. One-step selective benzene hydroxylation is an attractive yet challenging method for phenol production, especially when such a reaction can be driven by solar energy. Herein, we reported that a highly selective benzene hydroxylation to phenol can be achieved over two Fe-based metal–organic frameworks [MIL-100(Fe) and MIL-68(Fe)] under visible light irradiations using hydrogen peroxide (H2O2) as an oxidant. An optimal benzene conversion of 30.6% was achieved with a H2O2:benzene ratio of 3:4 over MIL-100(Fe) after 24 h irradiations. ESR results and the kinetic studies suggested that a successful coupling of the photocatalysis of Fe–O clusters in Fe-based metal–organic frameworks (MOFs) with a Fenton-like route is involved in this benzene hydroxylation process. The comparison of the reaction over MIL-100(Fe) and MIL-68(Fe) reveals that the structure of MOFs significantly influences the photocatalytic efficiency. Because the composition and the structure of MOFs are highly tunable, this study highlights the great potential of using Fe-based MOFs for photocatalytic benzene hydroxylation to form phenol, which may result in an economical, sustainable, and thus green process for phenol production.
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Journal of Materials Chemistry A
·
2014
·Vol. 2
·期 30
·11768-11775
·
IF 0
Yi Yao,Hui Xiao,Peng Wang,Panpan Su,Zhigang Shao,Qihua Yang
The development of non-precious metal catalysts for oxygen reduction reactions (ORRs) is of extreme importance for the construction of efficient H2/O2 polymer electrolyte membrane fuel cells (PEMFCs), one of the most promising clean energy technologies. Herein, we report the fabrication of core–shell structured CNTs@Fe–N–C composites with a Fe–N–C shell closely wrapped around a core of CNTs (carbon nanotubes) as efficient catalysts for ORR. CNTs@Fe–N–C composites afford comparable activity to commercial Pt/C catalysts with a loading of 20 μg Pt cm−2 towards ORR in alkaline media. The results of XRD, TEM, XPS and 57Fe Mössbauer characterizations suggest that the high ORR activity of CNTs@Fe–N–C composites are mainly attributed to the combined advantages of the unique core–shell nanostructure allowing close contact between Fe–N–C and CNTs, uniformly distributed FeN4/C species, and the presence of pyridine and graphitic nitrogen.
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JOURNAL OF ADVANCED OXIDATION TECHNOLOGIES
·
2016
·Vol. 19
·期 2
·358-365
·
IF 0.738
Yanfang Liu,Guixia Li,Zhili Zhang,Xiang Gao,Jianrui Niu,Junna Zhao,Zaixing Li
γ-Al 2 O 3 supported Manganese and Ferric oxide (Mn-Fe/Al 2 O 3 ) were synthesized and used as catalyst for ozonation of bisphenol A (BPA) in aqueous solution. It was conducted in a semi-batch reactor under different operational conditions, i.e., varying initial pH, ozone flow rate, initial BPA concentration and catalyst dosage. The results indicated that the presence of Mn-Fe/Al 2 O 3 lead to a great enhancement in ozonation of BPA. Using 5 g/L Mn-Fe/Al 2 O 3 evaluated BPA (50 mg/L) removal efficiency up to 84.1% under particular reaction conditions, while that of the single ozonation process was 48.5%. The influence of tert-butanol demonstrated that initiation of hydroxyl radicals was involved and plays an important role in catalytic ozonation. The decrement of solution pH in catalytic ozonation was much higher than that in ozone alone, indicating much small molecule acids produced in catalytic ozonation process. The repeated use the Mn-Fe/Al 2 O 3 proved that it had a good reusability and stability.
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TALANTA
·
2016
·
IF 4.035
Qian Wen,Yuzhi Wang,Kaijia Xu,Na Li,Hongmei Zhang,Qin Yang,Yigang Zhou
Amino functional dicationic ionic liquid (AFDCIL) was prepared and then coated on the surface of magnetic graphene oxide (GO) as a new magnetic adsorbent (Fe@GO@AFDCIL) for the magnetic solid-phase extraction (MSPE) of protein. The Fe@GO@AFDCIL composite was characterized by vibrating sample magnetometer (VSM), X-ray diffraction (XRD), Fourier transform infrared spectrometry (FT-IR), thermal gravimetric analysis (TGA), field emission scanning electron microscopy (FESEM) and zeta-potential nanoparticles . The bovine hemoglobin (BHb) was used as the analyte, and the extraction performance of Fe@GO@AFDCIL was investigated in the MSPE procedure. The concentration of BHb in samples was determined by a UV–vis spectrophotometer. A comparative investigation of Fe@GO@AFDCIL composite and traditional IL-coated Fe@GO composites (Fe@GO@IL) exhibited the benefits of Fe@GO@AFDCIL. The adsorbed BHb could be eluted from the Fe@GO@AFDCIL by 4% sodium dodecyl sulfate (SDS) solution. The Fe@GO@AFDCIL exhibited favorable stability which could be reused at least 15 times. Under the optimized condition, the real samples were investigated, which demonstrated that the Fe@GO@AFDCIL was able to be applied in extracting bovine hemoglobin (BHb) from real biological samples.
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