Catalysts
·
2018
·Vol. 8
·期 5
·187
·
IF 3.465
Yanxia Li,Cheng Jiang,Shengheng Lin,Jiajia Lai,Liyun Zheng,Pengjun Xu
In this paper, gold/multi-walled carbon nanotube (Au/MWCNTs) composites were prepared via in situ reductions. The synthesized materials could effectively catalyze the system of square acid (SQA)-iron(II/III) to produce a significant color reaction. By designing the orthogonal test of three-factor and three-level, the three factors of sodium formate solution concentration, ultrasonic time and synthesis reaction time were optimized in the process of Au/MWCNTs preparation. Results showed that the Au/MWCNTs had the best catalytic activity under the conditions of sodium formate solution concentration of 400 mmol/L, ultrasonic for 30 min and reaction for 4 h. In a subsequent comparison with H2O2, it found that the catalytic performance of 1 mg of Au/MWCNTs composite was equivalent to that of H2O2with the concentration of 0.28 mmol/L. It demonstrated that the prepared Au/MWCNTs composites had good catalytic activity, stable color and low background noise, indicating a good prospect in various fields including that of catalytic reaction, sensing analysis, and nanomaterials labeling.Keywords:Au/MWCNTs composites;catalytic activity;square acid-iron(II/III) system
研究领域:
材料科学
·
催化化学
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产品关联
DOI
高影响因子
Polymers
·
2016
·Vol. 8
·期 11
·389
·
IF 2.944
Lihua Guo,Xinyu Jing,Shuoyan Xiong,Wenjing Liu,Yanlan Liu,Zhe Liu,Changle Chen
A series of alkyl- and aryl-substituted iminopyridine Fe(II) complexes1a–7aand Co(II) complexes2b,3b,5b, and6bwere synthesized. The activator effect, influence of temperature, and, particularly, the alkyl and aryl substituents’ effect on catalytic activity, polymer molecular weight, and regio-/stereoselectivity were investigated when these complexes were applied in isoprene polymerization. All of the Fe(II) complexes afforded polyisoprene with high molecular weight and moderatecis-1,4 selectivity. In contrast, the Co(II) complexes produced polymers with low molecular weight and relatively highcis-1,4 selectivity. In the iminopyridine Fe(II) system, the alkyl and aryl substituents’ effect exhibits significant variation on the isoprene polymerization. In the iminopyridine Co(II) system, there is little influence observed on isoprene polymerization by alkyl and aryl substituents.Keywords:iminopyridine;Iron(II);Cobalt(II);isoprene polymerization;selectivity
研究领域:
化学
·
高分子科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN
·
2018
·Vol. 91
·期 6
·998-1007
·
IF 3.526
Zhang Xuezhi,Jia Shaoyi,Song Jia,Wu Songhai,Han Xu
Flocculation using Fe(II) instead of Fe(III) has been considered more efficient in the removal of As. However, excess Fe(II) used in the process always leaves substantial TFe [Fe(II)+Fe(III)] unutilized. We therefore developed three methods [the one-staged process (OS), the one-staged process with H2O2 (OSH) and the two-staged process (TS)] to remove As(III)/As(V) by Fe(II) (Fe:As = 2.0). Our results indicate that pH is an important factor that determines the utilization efficiency of TFe and the removal efficiency of As. In OS, the initial pH was adjusted before the reaction. At the optimal pHs of 10.0 and 11.0, the removal efficiencies of As(V) and TAs [As(III)+As(V)] could reach 84.0% and 66.7%, with only 61.9% and 80.2% TFe being utilized, respectively. In OSH, H2O2 was added after pH adjustment. After OS, pH was re-adjusted to the optimal values before the next 30 min reaction (TS). Compared with OS, the removal efficiencies of As could increase by more than 9% in OSH and TS at the optimal pHs. Besides, there is more than 10% improvement in the utilization efficiencies of TFe except at 12.0. Accelerating oxidation of Fe(II) or re-adjusting pH is therefore highly efficient for a more efficient removal of As from Fe(II)-rich groundwater.
研究领域:
环境科学
·
水处理工程
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DOI
高影响因子
SPECTROSCOPY LETTERS
·
2014
·
IF 0.718
Rui-Yong Wang,Jing Wu,Lv-Jing Wang,Rui Wang,Huan-Jing Dou
Water-soluble and stable CdTe quantum dots were synthesized in aqueous solution with thioglycolic acid as the stabilizer. A spectrofluorometric method for the determination of iron (II) has been developed based on quenching of the fluorescence of CdTe quantum dots by iron (II) in aqueous solutions. It can perform an accurate and simple determination of iron (II) concentration in water samples. Under optimum conditions, the quenched fluorescence intensity increased linearly with the concentration of iron (II) ranging from 5.0 × 10−8 to 4.0 × 10−6 mol/L with a correlation coefficient R = 0.9969. The limit of detection for iron (II) was found to be 1.2 × 10−8 mol/L. As an application, the proposed method was successfully applied to the analysis of iron (II) in water samples, and the results were satisfactory.
研究领域:
分析化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2019
·
IF 5.108
Xin Liu,Baoling Yuan,Jing Zou,Lingbin Wu,Lin Dai,Hongfang Ma,Kai Li,Jun Ma
The activation of persulfate by Fe(II) coupled with hydroxylamine (the HA/Fe(II)/PS system) was highly effective for the degradation of refractory organic contaminants under acidic pH conditions. However, owing to the precipitation of ferric hydroxide and/or the slow reduction from Fe(III) to Fe(II), the HA/Fe(II)/PS system was invalid under neutral and alkaline pH conditions. In this study, it was observed that the degradation of acid orange 7 (AO7) was strongly enhanced over the wide pH range of 2–9 when trace Cu(II) (0.5–5 μM) was spiked into the HA/Fe(II)/PS system. It was evident that Cu(I) was generated via the reduction of Cu(II) by HA in the bimetallic system at both pH 3 and pH 8, and the steady concentration of Fe(II) in the bimetallic system was much higher than that in the HA/Fe(II)/PS system due to the rapid reaction between Fe(III) and Cu(I). Quenching experiments using tert-butyl alcohol, methanol and sodium bromide as the scavengers and electron spin resonance experiments confirmed that the primary reactive species responsible for AO7 degradation were sulfate radical at both pH 3 and pH 8, rather than hydroxyl radical and Cu(III). Nevertheless, sulfate radical was mainly produced by Fe(II)-activated PS at pH 3, while both Cu(I) and Fe(II) made important contributions to the generation of sulfate radical at pH 8. The bimetallic system was also highly effective in degrading other organic contaminants, such as phenol, diclofenac, reactive red 2 and orange G. This study might provide a promising idea based on Fe(II)-activated PS for degrading organic contaminants over a wide pH range.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
·
2016
·
IF 5.991
Zhexin Zhu,Yi Chen,Yan Gu,Fei Wu,Wangyang Lu,Tiefeng Xu,Wenxing Chen
Iron (II) phthalocyanine (FePc) molecules were isolated in polyacrylonitrile (PAN) nanofibers by electrospinning to prevent the formation of dimers and oligomers . Carbamazepine (CBZ) and Rhodamine B (RhB) degradation was investigated during a Fenton-like process with FePc/PAN nanofibers. Classical quenching tests with isopropanol and electron paramagnetic resonance tests with 5,5-dimethyl-pyrroline-oxide as spin-trapping agent were performed to determine the formation of active species during hydrogen peroxide (H 2 O 2 ) decomposition by FePc/PAN nanofibers. After eight recycles for CBZ degradation over the FePc/PAN nanofibers/H 2 O 2 system, the removal ratios of CBZ remained at 99%. Seven by-products of RhB and twelve intermediates of CBZ were identified using ultra-performance liquid chromatography and high-resolution mass spectrometry. Pathways of CBZ and RhB degradation were proposed based on the identified intermediates. As the reaction proceeded, all CBZ and RhB aromatic nucleus intermediates decreased and were transformed to small acids, but also to potentially toxic epoxide-containing intermediates and acridine, because of the powerful oxidation ability of • OH in the catalytic system.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
·
2023
·
IF 12.8
Bin Liu,Yin Jun,Changrong Zhao,Chu Zhou,Tingting Zhu,Senlin Shao
Ultrafiltration (UF) is a technology commonly used to treat secondary effluents in wastewater reuse; however, it faces two main challenges: 1) membrane fouling and 2) inadequate nitrogen (N), phosphorus (P), and organic micropollutants (OMPs) removal. To address these two issues, in this study, we applied peracetic acid (PAA), Fe(VI)/PAA, and Fe(II)/PAA as UF pretreatments. The results showed that the most effective pretreatment was Fe(II)/200 μM PAA, which reduced the total fouling resistance by 90.2%. In comparison, the reduction was only 29.7% with 200 μM PAA alone and 64.3% with Fe(VI)/200 μM PAA. Fe(II)/200 μM PAA could effectively remove fluorescent components and hydrophobic organics in effluent organic matter (EfOM), and enhance the repulsive force between foulants and membrane (according to XDLVO analysis), and consequently, mitigate pore blocking and delay cake layer formation. Regarding pollutant removal, Fe(II)/200 μM PAA effectively degraded OMPs (>85%) and improved P removal by 58.2% via in-situ Fe(Ⅲ) co-precipitation. The quencher and probe experiments indicated that Fe IV O 2+ , •OH, and CH 3 C(O)OO•/CH 3 C(O)O• all played important roles in micropollutant degradation with Fe(II)/PAA. Interestingly, PAA oxidation produced highly biodegradable products such as acetic acid, which significantly elevated the BOD 5 level and increased the BOD 5 /total nitrogen (BOD 5 /TN) ratio from 0.8 to 8.6, benefiting N removal with subsequent denitrification. Overall, the Fe(II)/PAA process exhibits great potential as a UF pretreatment to control membrane fouling and improve water quality during secondary effluent treatment.
研究领域:
环境科学
·
水处理工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Environmental Science-Nano
·
2023
·Vol. 10
·期 10
·2744-2753
·
IF 7.3
Jiaxin Lv,Ruixin Chen,Zhen Wu,Yang Bai,Han Song,Chen Tian,Mengye Wang,Zhang Lin
The enrichment of microplastics in polar ice is a typical phenomenon discovered in recent years. Thus, it is worthwhile to explore the degradation behavior of microplastics in frozen environments, which is crucial to evaluate their impact on polar ecosystems. Here, taking polystyrene (PS) as an example, the degradation behaviors of MPs in frozen anoxic Fe(II)-containing solutions were investigated. The results revealed that PS degradation rate in frozen solution was 14.6-fold higher than that in water. Mechanism study showed that freezing-induced aggregation and extrusion of PS enhanced the generation of environmentally persistent free radicals (EPFRs), which in turn contributed to the formation of H2O2. Moreover, freezing-induced enrichment of Fe(II) further interreacted with H2O2 to form Fe(IV) and OH free radicals at a pH of ∼6.5, and thus accelerated the degradation of PS. Such reaction was accompanied by the formation of Fe(III)-containing products, which would further react with aged PS to produce new EPFRs and Fe(II). Such cycles of aged PS/EPFRs and Fe(III)/Fe(II) continued to accelerate the degradation of PS in the frozen solution. This study provides an overlooked pathway for microplastic degradation in frozen Fe(II)-containing solutions, which would be of key importance to understand the degradation behaviors of microplastics in frozen environments.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
DYES AND PIGMENTS
·
2021
·
IF 4.889
Yu Kuai,Tao Yang,Feiya Yuan,Yujie Dong,Qingbao Song,Cheng Zhang,Wai-Yeung Wong
A new metallo-supramolecular film was prepared by a liquid–liquid interface self-assembly method based on the metal ion Fe(II) in water solution and a star-shaped ligand of triphenylamine-substituted alkyl terpyridine in organic solvents . The film obtained exhibited excellent flexibility due to the presence of flexible alkyl arms, and could tightly adhere to the surface of ITO glass with very smooth surface morphology via SEM characterization. Spectroelectrochemical experiments demonstrated that the film displayed the electrochromism with purplish color in the neutralized state at 0 V vs Ag/AgCl turning to yellow-green color in the oxidized state at 1.2 V vs Ag/AgCl. This work further indicates that the liquid–liquid interfaciad self-assembly method is a promising strategy to prepare the metallo-supramolecular film towards electrochromic applications.
研究领域:
材料科学
·
电化学
·
超分子化学
✓ 已验证
DOI
高影响因子
JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2019
·Vol. 57
·期 7
·767-775
·
IF 2.591
Xianhui Zhang,Guangqian Zhu,Qaiser Mahmood,Mengmeng Zhao,Liang Wang,Chuyang Jing,Xiaowu Wang,Qinggang Wang
A stereoselectivity switchable polymerization of isoprene has been developed, which is catalyzed by iminoimidazole-Co(II) and -Fe(II) complexes. The influence of substituents ranging from electron donating to the electron withdrawing on the iminoimidazole-Co(II) and -Fe(II) catalysts is investigated for isoprene polymerization. Two sets of iminoimidazole-Co(II) and -Fe(II) complexes have been prepared and fully characterized. X-ray crystallography analysis reveals that the complexes Co1 and Fe1 adopt distorted tetrahedral geometries. In the presence of AlEt 2 Cl as co-catalyst, all the Co(II) complexes are active and the catalytic activity is highly dependent on the molar ratio of Al/Co. All the Co(II) complexes exhibit higher activities at low Al/Co ratio. Compared with the Co(II) complexes, the Fe(II) complexes are essentially inactive under the identical condition. However, on activation with combination of AlEtCl 2 and [Ph 3 C][B(C 6 F 5 ) 4 ], both Co(II) and Fe(II) complexes display high activities with good conversions of isoprene (up to >99%). Additionally, low molecular weight and high trans -1,4-unit (>96%) selectivity are characteristics of the resultant polyisoprene. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57 , 767–775
研究领域:
化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
INORGANICA CHIMICA ACTA
·
2016
·
IF 1.918
Na Zhang,Sihan Wang,Lei Song,Cuiqin Li,Jun Wang
A series of novel hyperbranched salicylaldimine iron (II) complexes have been synthesized and characterized with IR, UV, MS and TG. These iron coordinative complexes, activated with methylaluminoxane (MAO), exhibited moderate activities in ethylene oligomerization (TOF = 2.62–9.19 × 10 4 g/mol Fe·h), giving higher selectivity (7.37–24.44%) for higher carbon number olefins (C 10+ ). As reaction temperature increased, the catalytic activities firstly increased and then decreased, but the product distributions were almost independent on the temperature. With the increase of the Al/Fe molar ratio and the ethylene pressure, the catalytic activity increased rapidly and the selectivity of higher carbon number olefins increased at first and then decreased. In addition, the nature of solvent and co-catalyst, as well as the structure of catalyst significantly affected both the catalytic activities and product compositions of the resultant catalysts. Under optimized conditions ([Fe] = 7 μmol, 25 °C, Al/Fe = 500, 0.5 MPa ethylene), pre-catalyst Fe1 led to catalytic activity of 6.91 × 10 4 g/mol Fe·h and 20.48% selectivity for higher carbon number olefins.
研究领域:
有机化学
·
催化化学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2022
·Vol. 12
·期 49
·31959-31965
·
IF 4.036
Chunde Li,Hua Wei,Xueyan Hu,Zhaoxian Chen,Xin Xie,Guo Chen,Anping Liu,Yingzhou Huang,Weijia Wen
Electrorheological (ER) fluid, containing polarized particles within an insulating liquid, represents a smart material, the mechanical properties of which can be altered mainly by an electric field. In this work, ER fluids based on cauliflower iron(II) oxalate doped titanium particles show excellent rheological and wetting properties by the sample co-precipitation method. The morphology of the particles is observed by SEM and the molecular structure within the particles is obtained via XRD and FTIR. The distribution of elements within the particles is obtained by EDS. Owing to a lower current density than pure iron(II) oxalate, the SEM and optical images show an obvious chain-like structure within the ER fluids with 2 wt% and 5 wt%, respectively, under 2 kV mm−1. Then, the rheological properties of these ER fluids are tested up to 3 kV mm−1 and the results show a gratifying property of resisting shear with different shear rates (0.1–100 s−1), which is attributed to the appearance of a stable chain-like structure. At the same time, the ER efficiency and the switching performance are obtained and the static yield stress fits the relevant electric field strength well. Ultimately, an excellent sedimentation ratio is obtained from 0 h to 600 h.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）