WATER RESEARCH
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2018
·
IF 7.051
Zisheng Zhao,Yaobin Zhang,Yang Li,Xie Quan,Zhiqiang Zhao
Anaerobic digestion is one of the most promising technologies to stabilize waste-activated sludge (WAS) and recover energy. However, the low efficiency of anaerobic digestion of WAS constrains its application. Supplementing zero valent iron (ZVI) and Fe 3 O 4 in digesters could improve the sludge digestion performance, which has recently been extensively studied. However, the mechanisms behind this improvement remain unclear. In this study, the effects of ZVI and Fe 3 O 4 on the four stages of anaerobic digestion of WAS (solubilization, hydrolysis, acidification and methanogenesis) were investigated. Results showed that ZVI had only a slight effect on the solubilization , hydrolysis and acidification processes, while ZVI significantly promoted the hydrogenotrophic methanogenesis , increasing methane production by 70%. Further investigation indicated that coenzyme F420 activity in the ZVI added reactor was 32.3% higher than in the blank. These results indicate that ZVI promoted anaerobic digestion of WAS through promoting hydrogenotrophic methanogenesis. On the other hand, Fe 3 O 4 obviously promoted the solubilization, hydrolysis and acidification of sludge. Vast Fe 2+ was detected in the aqueous phase of the Fe 3 O 4 digester which was a result of dissimilatory iron reduction that can utilize complicated matter as a substrate. This was in agreement with the acceleration of the solubilization, hydrolysis and acidification of the sludge. However, the acetoclastic and hydrogenotrophic methanogenesis with Fe 3 O 4 decreased by 27% and 22% compared to the Fe 3 O 4 -free digester, respectively. Further study indicated that Fe 3 O 4 competed with CH 3 ▪S▪CoM for electrons and thus inhibited the methanogenesis process.
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ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Yu-Xia Li,Yu-Nong Ji,Meng-Meng Jin,Shi-Chao Qi,Shuai-Shuai Li,Ding-Ming Xue,Ming Bo Yue,Xiao-Qin Liu,Lin-Bing Sun
Here, we designed a double-solvent/host–guest redox combined strategy to construct Cu+ sites in metal–organic frameworks (MOFs) for the first time. As a proof of concept, a representative MOF MIL-100(Fe) with tunable valence states of cations was employed as the host. The combined strategy realizes selective introduction of Cu2+ precursors to the interior pores of MIL-100(Fe), remarkably minimizing the aggregation of Cu2+ and subsequently formed Cu+ species. Owing to the proper reducibility of in situ formed Fe2+ in the frameworks, controlled conversation of Cu2+ to Cu+ with ∼100% yield is achieved in the absence of any additional reducing agents. These characteristics make the obtained materials Cu+-modified MIL-100(Fe) highly active in selective CO adsorption. The CO adsorption capacity is up to 3.75 mmol·g–1 at 298 K and 1 bar, which is superior to all other Cu+-containing adsorbents reported so far such as CuCl/activated carbon (2.5 mmol·g–1), CuCl/γ-Al2O3 (1.0 mmol·g–1), and CuCl/SBA-15 (0.50 mmol·g–1). The same adsorbent also exhibits quite high selectivity of CO over N2, and the ideal adsorption solution theory selectivity reaches 424. The outstanding CO adsorption performance make the present adsorbents great potential in separation of CO from various mixtures.
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BIORESOURCE TECHNOLOGY
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2019
·
IF 6.669
Chunhua He,Weishi Lin,Xiaohao Zheng,Chuanya Wang,Zhenhu Hu,Wei Wang
Anaerobic digestion is widely employed for treating phenol-containing wastewater, but there are still some drawbacks such as slow phenol degradation rate and vulnerable acetoclastic methanogens. Coupling of magnetite (Fe 3 O 4 ) and zero valent iron (ZVI) was firstly used to enhance anaerobic digestion of phenol. The results indicated an obvious synergistic effect was generated with coupling of Fe 3 O 4 and ZVI during the whole anaerobic digestion of phenol. The phenol degradation rate and methane production of Fe 3 O 4 /ZVI-added group were increased by 8.8–23.1% and 11.9–31.6%, respectively compared with Fe 3 O 4 -added group, and enhanced by 5.9–17.1% and 4.4–18.3%, respectively compared with ZVI-added group. ZVI improved the growth of hydrogenotrophic methanogens and Fe 3 O 4 enhanced the growth of syntrophic acetate-oxidizing bacteria. Finally, the syntrophic interaction between acetate-oxidizing bacterium and hydrogenotrophic methanogens played a vital role on the synergistic effect of Fe 3 O 4 and ZVI on the whole anaerobic phenol digestion.
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SCIENCE OF THE TOTAL ENVIRONMENT
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2019
·
IF 5.589
Cong Lyu,Dan He,Yuming Chang,Qihui Zhang,Fang Wen,Xiansheng Wang
The persulfate/Fe 2+ system has been proposed for the chemical oxidation for soil remediation , however, the homogeneous iron catalyst was hard to reuse which limited the further application. Cobalt oxyhydroxide (CoOOH) existed as a mineral in nature, which was environmentally friendly. Thus, in this study, CoOOH was selected as an efficient heterogeneous catalyst for peroxymonosulfate (PMS) activation to remediate oil contaminated soil by chemical oxidized reaction. 88.3% of oil at the initial concentration of 78–99 mg/kg can be removed within 24 h under the conditions of 1.0 g/L CoOOH and 0.1 M PMS at room temperature. The residual oil content was approximately 11.5 mg/kg which was lower than the standard of petroleum hydrocarbons for residential land (30 mg/kg), published by the Canadian Council of Ministers of the Environment (CCME). Specifically, the PMS/CoOOH system had a relatively high apparent reaction rate constant (0.3078 h −1 ), which was approximately twice that of the PS/Fe 2+ system (0.1601 h −1 ). Furthermore, multiple radicals and reactive oxygen species (ROS), such as SO 4 − , O 2 − and 1 O 2 , were involved in the oil removal oxidation reaction. Moreover, 73% total organic carbon (TOC) had been removed after the reaction. The findings of this study suggested that the oil-contaminated soil and CoOOH could both be recycled after remediation using the PMS/CoOOH system. In summary, the results indicated that CoOOH is a promising heterogeneous catalyst, and the PMS/CoOOH system could be considered as a feasible alternative to the PS/Fe 2+ system for the remediation of oil-contaminated soil.
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ELECTROANALYSIS
·
2018
·Vol. 30
·期 11
·2768-2773
·
IF 2.851
Xin Feng,Xiaomei Dong,Qingcheng Zhang,Cuixia Cui,JingJing Zhang,Zhen Chen,Changmi Wu,Huile Jin,Shun Wang,Jichang Wang
In this study carbon materials with a hierarchical pore structure have been fabricated through a scalable and template free solvothermal method in the presence of metal catalysts, where the presence of metal catalysts was found to be essential for the initial polymerization process. The as-prepared carbon contained trace amounts of metal residues and exhibited highly efficient catalytic activity toward the oxygen reduction reaction (ORR). Among all the metal catalysts studied, cobalt containing porous carbon exhibited the highest ORR electrocatalytic activity with great tolerance to methanol crossover and excellent long-term cycling stability, outperforming the commercial 30 % ( w / w ) Pt/C catalysts. The great performance may be contributed to the unique porous structure, the large specific surface area of cobalt-doped carbon and chemical activity of cobalt. The result provides useful guidance for the development of carbon-based electrocatalysts.
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CHEMICAL ENGINEERING JOURNAL
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2018
·
IF 6.735
Yang Wu,Lifeng Lin,Fidèle Suanon,Anyi Hu,Ya-Nan Sun,Zhi-Min Yu,Chang-Ping Yu,Qian Sun
The aim of this study was to quantify the removal of halogenated pollutants (using triclosan as a model pollutant) from aqueous solution by zero-valent iron coupled with a weak magnetic field. We determined the removal efficiency of triclosan from a sodium sulfate solution at different pH values under both aerobic and anaerobic conditions. The removal of triclosan followed pseudo-first-order kinetics in both the presence and absence of a weak magnetic field. The calculated rate constants indicated higher removal efficiencies of triclosan under the aerobic condition compared to the anaerobic condition. In addition, increase of triclosan removal from acidic solutions was achieved with the assistance of weak magnetic field. X-ray diffraction and X-ray photoelectron spectroscopy analysis indicated that FeO(OH) and Fe 3 O 4 were the main aerobic transformation products, suggesting that the zero-valent iron surfaces were completely oxidized. The aerobic and anaerobic transformation products of triclosan were analyzed by liquid chromatography tandem mass spectrometry. The results indicated that the application of a weak magnetic field could be an efficient and cheap treatment process to improve the removal of halogenated pollutants by zero-valent iron, which may be developed for future use.
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Nano Research
·
2015
·Vol. 8
·期 10
·3237-3249
·
IF 7.01
Liang Ruowen,Jing Fenfen,Shen Lijuan,Qin Na,Wu Ling
Proper design and preparation of high-performance and stable dual functional photocatalytic materials remains a significant objective of research. In this work, highly dispersed noble-metal nanoparticles (Au, Pd, Pt) were immobilized on MIL-100(Fe) (denoted M@MIL-100(Fe)) using a facile room-temperature photodeposition technique. The resulting M@MIL-100(Fe) (M = Au, Pd, and Pt) nanocomposites exhibited enhanced photoactivities toward photocatalytic degradation of methyl orange (MO) and reduction of heavy-metal Cr(VI) ions under visible-light irradiation (λ ≥ 420 nm) compared with blank-MIL-100(Fe). Combining these results with photoelectrochemical analyses revealed that noble-metal deposition can effectively improve the charge-separation efficiency of MIL-100(Fe) under visible-light irradiation. This phenomenon in turn leads to the enhancement of visible-light-driven photoactivity of M@MIL-100(Fe) toward photocatalytic redox reactions. In particular, the Pt@MIL-100(Fe) with an average Pt particle size of 2 nm exhibited remarkably enhanced photoactivities compared with those of M@MIL-100(Fe) (M = Au and Pd), which can be attributed to the integrative effect of the enhanced light absorption intensity and more efficient separation of the photogenerated charge carrier. In addition, possible photocatalytic reaction mechanisms are also proposed.
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JOURNAL OF CHROMATOGRAPHY A
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2012
·
IF 4.531
Yan-Yan Fu,Cheng-Xiong Yang,Xiu-Ping Yan
Metal-organic framework MIL-100(Fe) was explored as a novel stationary phase for both normal-phase and reverse-phase high performance liquid chromatography. Two groups of analytes (benzene, toluene, ethylbenzene, naphthalene and 1-chloronaphthalene; aniline, acetanilide, 2-nitroaniline and 1-naphthylamine) were used to test the separation performance of MIL-100(Fe) in the reverse-phase mode, while the isomers of chloroaniline or toluidine were employed to evaluate its performance in the normal-phase mode. The MIL-100(Fe) packed column gave a baseline separation of all the tested analytes with good precision. The separation was controlled by negative enthalpy change and entropy change in the reverse-phase mode, but positive enthalpy change and entropy change in the normal-phase mode. The relative standard deviations of retention time, peak area, peak height, and half peak width for eleven replicate separations of the tested analytes were 0.2–0.7%, 0.5–3.6%, 0.6–2.3% and 0.8–1.7%, respectively. The mesoporous cages, accessible windows, excellent chemical and solvent stability, metal active sites and aromatic pore walls make MIL-100(Fe) a good candidate as a novel stationary phase for both normal-phase and reverse-phase high performance liquid chromatography.
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Analytical Methods
·
2015
·Vol. 8
·期 6
·1239-1248
·
IF 1.821
Shaolin Li,Yangyang Ding,Wei Wang,Hong Lei
Zero valent iron (ZVI) is increasingly used in large quantities for water treatment. In large-scale application of ZVI, a common question that engineers encounter is ZVI selection or its quality assurance and quality control (QA/QC). A facile method for assessing ZVI quality is proposed and studied in this work. The method is based on the Fe(III)–Fe(0) reaction that has a fast reaction rate, a known and simple stoichiometry, and an easy-to-assay product. The method is conducted by mixing the sample (e.g., testing ZVI) with concentrated Fe(III) solution (up to 3.0 g L−1) for 3–4 hours. The metallic iron (Fe(0)) content of the sample is obtained by assaying the final increase of the total dissolved iron, and its reactivity is quantified using the observed dissolution rate constants. The method is experimentally validated using 23 iron-based materials. Studies with reference iron powder and iron oxide demonstrate that the Fe(III) solution has satisfactory specificity in selecting Fe(0). Replicate experiments and t-test evaluation show the complete dissolution of the Fe(0) content in micron-scale ZVI and the high reproducibility of the method for measuring Fe(0). The accuracy and reliability of the method are studied using 15 commercial ZVIs of known Fe(0) purity, in a series of experiments using Fe(III), Cu(II) or trichloroethylene. The experiments show that the results from the proposed method are accurate and reliable, and that the method is a strong tool more effective than conventional techniques such as X-ray diffraction and BET-N2 adsorption. This work provides an easy and facile way for the quantitative assessment of the quality of metallic iron used for environmental clean-up, especially for the quick survey of a large number of iron samples on site. The method may also serve as a QA/QC procedure for ZVI in industrial-scale production.
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CHEMICAL ENGINEERING JOURNAL
·
2014
·
IF 4.058
Huanxuan Li,Jinquan Wan,Yongwen Ma,Mingzhi Huang,Yan Wang,Yangmei Chen
Batch tests were conducted to investigate the effect of initial pH on the degradation of dibutyl phthalate (DBP), the formation and evolution of iron corrosion products, and the role of iron oxides on the further degradation of DBP in zero-valent iron (ZVI)–persulfate system. The study indicated that the half-lives for the oxidation of DBP by persulfate activated with ZVI were 30–176 min at pH 3.0–11.0. The constituents and the morphology of the iron corrosion coating along different initial pH and over reaction time were investigated with Raman spectroscopy , X-ray photoelectron spectroscopy and Scanning electron microscopy. The results illustrated that magnetite (Fe 3 O 4 ), wustite (FeO), hematite (α-Fe 2 O 3 ) and goethite (α-FeOOH) were identified as the corrosion products. In alkaline and neutral solutions, the inner layer of iron oxides was mainly composed of α-Fe 2 O 3 with some α-FeOOH while the outer layer mostly consisted of Fe 3 O 4 and α-FeOOH. Oppositely, the iron oxides formation in acidic solution mainly consisted of Fe 3 O 4 , α-FeOOH and a small amount of α-Fe 2 O 3 and FeO in the inner layer, the outer layer was mostly composed of α-Fe 2 O 3 and some α-FeOOH. These iron corrosion coatings exhibited an inhibitory effect on the degradation of DBP, which may be due to that the iron oxides hindered the electron transfer from ZVI core to the solid–liquid interface.
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POLYMER INTERNATIONAL
·
2015
·Vol. 64
·期 12
·1715-1721
·
IF 2.409
Tao Xing,Kai Zhang
Novel carborane polyimides were synthesized and studied. Aromatic meta -carborane diamines of different structures were initially prepared. Polymerization of these new diamines with the commercially available 4,4′-oxydiphthalic dianhydride led to meta -carborane polyimides with various structures and thermal properties. The amorphous polymers obtained are of moderate molecular weight and show good solubility in organic solvents. Thermal analyses of these polyimides reveal that they have moderate to ultrahigh thermal stability depending on their specific structures, with 5% decomposition temperatures ranging from 382 to 786 °C in nitrogen. Different thermal properties of these polyimides are observed when the analyses are performed in dry air, with 5% decomposition temperatures shifting to temperatures ranging from 388 to 1128 °C. Due to the ever-present requirement of higher performance polymers in fields like aerospace and defense, the methods developed here could be an impetus for the development of these industries. © 2015 Society of Chemical Industry
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Journal of Material Cycles and Waste Management
·
2013
·Vol. 15
·期 4
·461-468
·
IF 0.568
Su Lianghu,Shi Xinlong,Guo Guangzhai,Zhao Aihua,Zhao Youcai
The potential benefits of nanoscale zero-valent iron (nZVI) on sludge stabilization, either the abatement of odor or the improvement of biogas production, were investigated in this study. Two commercial-grade microscale iron powders were also utilized for comparison. Adding 0.10 wt% of nZVI in sludge during anaerobic incubation significantly reduced the concentration of H 2 S in biogas by 98.0 % (96.2–98.9 %), probably attributed by reactions between sulfides and the neo-formed hydrous Fe(II)/Fe(III) oxides layer at the surface of ZVI nanoparticles. Meanwhile, the percentage of P in bioavailable fractions decreased from 76.8 to 52.5 %, possibly due to the formation of vivianite [Fe 3 (PO 4 ) 2 ]. Furthermore, 0.10 wt% of nZVI in anaerobic digestion for 17 days enhanced the concentration of CH 4 in biogas by 5.1–13.2 % and improved the production of biogas and methane by 30.4 and 40.4 %, respectively. The amendment of iron nanoparticles during anaerobic digestion can not only effectively reduce H 2 S in biogas, but also potentially boost methane production significantly.
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