ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2019
·Vol. 26
·期 10
·9480-9489
·
IF 2.914
Dai Shijin,Zheng Yilin,Zhao Youcai,Li Qiang,Niu Dongjie
Chlorine-containing organic waste (COWs) is a big threat for the waste incineration because of the dioxin generation and equipment corrosion. Recently, dechlorination and detoxification of COWs is emergent in order to lower the environmental risk and treatment costs. In this study, base-catalyzed decomposition processes with different hydroxides, hydrogen donors, and catalysts were conducted for pre-treatment of COWs to reduce organic chlorine content, with the TCB as a model compound and industrial rectification residues for verification. Results showed that maximum chlorine retention efficiency (CRE) of four alkalis followed the order of KOH > NaOH–KOH > NaOH > Mg(OH) 2 , which were 98.3%, 93.4%, 97.2%, and 1.5%, respectively, and could be expressed as an apparent first-order reaction. The differences were resulted from the varying ionic potentials of the metal cations. Hydrogen donors (glycol, glycerol, paraffin oil, and PEG 200) acted as effective dechlorination regents follow the order of PEG > glycol > paraffin oil > glycerol. In addition, Fe, Ni, Cu, and activated carbon catalysts increased the CRE by 68.9% to 92.4%, 91.9%, 89.2%, and 73.3%, respectively. Residue analysis through X-ray diffraction and Fourier transform infrared spectroscopy revealed that KCl, sodium oxalate, and phenol were the main products and a plausible stepwise dechlorination pathway was proposed. The effectiveness of three optimized combinations including NaOH/PEG, KOH/PEG, and NaOH–KOH/PEG (with the Fe catalyst) was confirmed by using them for dechlorinating rectification residues, and they restrained 98.2%, 91.2%, and 94.6% of the chlorine, respectively. The organochlorine content decreased from 19.2 to 1.8% within 180 min, while inorganic chorine content increased from 1.5 to 18.9%, indicating the potential for COWs dechlorination.
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NEW JOURNAL OF CHEMISTRY
·
2019
·Vol. 43
·期 24
·9725-9731
·
IF 3.069
Suresh Mutyala,Sobhy M. Yakout,Shebl S. Ibrahim,Madhavi Jonnalagadda,Harisekhar Mitta
Iron metal–organic framework, MIL-100(Fe) was prepared by a hydrothermal method and used as a support to incorporate diethylenetriamine (DETA) for the study of CO2 adsorption and separation of CO2/N2. All synthesized adsorbents were characterized by PXRD, N2 adsorption–desorption isotherms, FT-IR, TGA, SEM, and elemental analysis. Structural characterization results have revealed that the structure of MIL-100(Fe) was not changed by the incorporation of diethylenetriamine. The CO2 adsorption capacities were 29 cm3 g−1 and 41 cm3 g−1 at 298 K, 1 bar for MIL-100(Fe) and DETA–MIL-100(Fe), respectively. Adsorption of CO2 on DETA–MIL-100(Fe) was higher than that on MIL-100(Fe). The enhancement was due to the presence of amine groups which could form ammonium carbamate by interaction with CO2. Similarly, the N2 adsorption capacities were 3 cm3 g−1 and 0.9 cm3 g−1 at 298 K, 1 bar for MIL-100(Fe) and DETA–MIL-100(Fe), respectively. The decrease in N2 adsorption capacity was due to the decrease in surface area. The selectivity of CO2/N2 on DETA–MIL-100(Fe) was four times higher than that on MIL-100(Fe). The heat of CO2 adsorption was 74.2 kJ mol−1 at low coverage of CO2 on DETA–MIL-100(Fe) and the CO2 adsorption capacity was constant in each adsorption cycle over the same adsorbent.
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WATER ENVIRONMENT RESEARCH
·
2019
·Vol. 91
·期 8
·770-779
·
IF 1.24
Jinhong Fan,Hehe Qin,Yunfei Zhang,Simin Jiang
In this study, Fe/Cu bimetal composite was prepared by high-energy ball milling (BM) method for the removal of refractory organics. The BM Fe/Cu bimetal was characterized by SEM-EDS, XRD, and XPS. Evenly distributed Fe and Cu was observed in the EDS mapping. In contrasting experiments, the removal rate of 4-chlorophenol (4-CP) by BM Fe/Cu materials was about 10-fold faster than that by chemical substitution deposition (CSD) of Fe/Cu material. Complete 4-CP removal and 66.7% of total organic carbon (TOC) mineralization in the BM Fe/Cu–O 2 system were achieved. Dissolved oxygen plays a crucial role for 4-CP degradation through the in situ generation of reactive oxygen species (ROS) such as H 2 O 2 , ·OH, and via oxygen activation reactions. The predominant reactive radicals were identified to be and ·OH through ESR technique and inhibition experiments. The coexistence of oxidation and reduction of 4-CP in the BM Fe/Cu-O 2 system was proposed. Practitioner points 4-CP removal rate by BM Fe/Cu is 10-fold faster than that by CSD Fe/Cu at the same conditions. Complete 4-CP removal and 66.7% of TOC reduction were achieved. All three ROS including ·OH, , and H 2 O 2 coexisted in the BM Fe/Cu-O 2 system. A harmonious coexistence of oxidation and reduction mechanism was proposed.
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ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2019
·
IF 7.149
Qiuying Yi,Jiahui Ji,Bin Shen,Chencheng Dong,Jun Liu,Jinlong Zhang,Mingyang Xing
As an important reactive oxygen species (ROS) with selective oxidation, singlet oxygen (1O2) has wide application prospects in biology and the environment. However, the mechanism of 1O2 formation, especially the conversion of superoxide radicals (·O2–) to 1O2, has been a great controversy. This process is often disturbed by hydroxyl radicals (·OH). Here, we develop a molybdenum cocatalytic Fenton system, which can realize the transformation from ·O2– to 1O2 on the premise of minimizing ·OH. The Mo0 exposed on the surface of molybdenum powder can significantly improve the Fe3+/Fe2+ cycling efficiency and weaken the production of ·OH, leading to the generation of ·O2–. Meanwhile, the exposed Mo6+ can realize the transformation of ·O2– to 1O2. The molybdenum cocatalytic effect makes the conventional Fenton reaction have high oxidation activity for the remediation of organic pollutants and prompts the inactivation of Staphylococcus aureus, as well as the adsorption and reduction of heavy metal ions (Cu2+, Ni2+, and Cr6+). Compared with iron powder, molybdenum powder is more likely to promote the conversion from Fe3+ to Fe2+ during the Fenton reaction, resulting in a higher Fe2+/Fe3+ ratio and better activity regarding the remediation of organics. Our findings clarify the transformation mechanism from ·O2– to 1O2 during the Fenton-like reaction and provide a promising REDOX Fenton-like system for water treatment.
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ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2019
·
IF 7.149
Yue Hu,Xing Peng,Zhihui Ai,Falong Jia,Lizhi Zhang
In this study, we report that liquid nitrogen treatment is a promising zero-valent iron activation method that does not remove the iron oxide shell; this can improve the apparent Cr(VI) removal rate constant of zero-valent iron by about 4–120 times, depending on the particle sizes and the suppliers of zero-valent iron. It was found that liquid nitrogen, with its low temperature of 77 K, could crack the iron oxide shell of zero-valent iron to produce abundant fractures because of the different thermal expansion coefficients of iron oxide and iron. These fractures provided suitable mass transfer channels for the inward transfer of water/oxygen molecules to the iron core and the subsequent in situ generation of Fe(II) for the reduction of Cr(VI) to Cr(III). More importantly, systematic characterizations confirmed the generation of an Fe(III)/Cr(III)/Cr(VI) composite on the surface of zero-valent iron during the removal, suggesting its environmental benignancy. This study provides a novel physical zero-valent iron activation method, sheds light on the importance of the iron oxide shell of zero-valent iron on Cr(VI) removal, and clarifies the intrinsic Cr(VI) removal mechanism of zero-valent iron.
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SCIENCE OF THE TOTAL ENVIRONMENT
·
2019
·
IF 5.589
Zhen Bi,Wenjing Zhang,Ge Song,Yong Huang
Anammox bacteria are chemolithotrophic organisms growing on the conversion of ammonium and nitrite with bicarbonate as the sole carbon source. Meanwhile, anammox bacteria display a metabolic versatility to sustain their metabolism. However, there is less attention on the Fe 0 /Fe 2+ -dependent autotrophic denitrification by anammox consortia. In this study, the autotrophic nitrate reduction using different valence of iron (Fe 0 , Fe 2+ and Fe 0 + Fe 2+ , respectively) as electron donors by anammox consortia were firstly explored in continuous feeding mode. Results revealed anammox consortia showed high adaptability to the niche wherein containing nitrate and iron. They could generate nitrite and ammonium from iron-dependent nitrate reduction, and hence support their central metabolism. During 60-days operation, the maximum nitrate and total nitrogen removal efficiency reached 88.43% and 80.77%, respectively, with coexistence of Fe 0 and Fe 2+ . The expression of key functional genes involved in nitrate reduction (including narG, napA and nrfA ) in 16S rRNA level revealed the coupling of dissimilatory nitrate reduction to nitrite, dissimilatory nitrite reduction to ammonia (DNRA), and anammox processes possibly play pivotal role in nitrogen loss under Fe 0 /Fe 2+ condition. Meanwhile, abiotic reduction by Fe 0 /Fe 2+ also contributed nitrate reduction to provide nitrite and ammonium for anammox consortia. Activities of two vital enzymes hydrazine dehydrogenase (HDH) and nitrate oxidoreduetase (NAR) also inferred higher microbial activities with co-existence of Fe 0 and Fe 2+ . The present study confirms and further extends the versatile metabolisms of Anammox consortia, also it can help to circumvent the accumulation of nitrate produced by anammox process itself and increase the quality of discharge.
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JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2019
·
IF 4.978
Zhenjiang He,Yuxi Yang,Peng Bai,Xianghai Guo
Selective adsorption and separation of three xylene isomers of seven stable metal-organic frameworks (MOFs) were investigated, where MIL-53(Cr) manifested the highest adsorption capacity and apparent preference for o -xylene. Further detailed studies with MIL-53(Cr) showed that pseudo-second-order model fit best with adsorption kinetics of xylene isomers, and the isotherms were perfectly fitted by Langmuir isotherm model. The adsorption was proved to be a quick process, and both the changes of entropy and enthalpy contributed to the o -xylene selectivity, but which mainly resulted from the entropy effect. The adsorption capacity of preferable isomer o -xylene, on account of better packing efficiency, was record-breaking 8.19 mmol/g, and selectivity of OX/PX, OX/MX and MX/PX were 13.75, 8.01 and 1.72, respectively. Both the adsorption capacity and OX selectivity on MIL-53(Cr) in liquid phase adsorption and breakthrough experiments were super high, which discriminated it from zeolites and other materials reported so far. Combined with extremely short equilibrium time and high stability, MIL-53(Cr) can be a promising adsorbent for separation of xylenes in industrial process.
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CHEMOSPHERE
·
2019
·
IF 5.108
Meimei Du,Yongqing Zhang,Imtyaz Hussain,Xiaodong Du,Shaobin Huang,William Wen
In this study, the enhanced effect of pyrite (FeS 2 ) on zero-valent iron (Fe 0 ) corrosion for arsenic (As) removal was investigated in a combined-Fe 0 /FeS 2 system. The effects of different Fe 0 /FeS 2 composition, dosage and initial pH were evaluated by batch experiments. Results showed that the best combination ratio of Fe 0 :FeS 2 (w/w) was 1:1 and the optimal dosage of mixture was 2.0 g/L. The combination of Fe 0 and FeS 2 in a system significantly enhanced the reactivity of Fe 0 for effective As removal within a broad pH range (3.0–9.0). The effective As removal in the combined-Fe 0 /FeS 2 system was primarily ascribed to being enhanced corrosion of Fe 0 by addition of FeS 2 . SEM and XRD characterizations strongly verified this point. Specifically, the mechanism study (the releases of Fe 2+ and total Fe ion, variations of pH values as well as XPS characterization) suggested that FeS 2 in the combined-Fe 0 /FeS 2 system could alleviate the passivation of Fe 0 (pH ini 3.0–5.0) and accelerate the dissolution of pristine oxide film that coated on Fe 0 surface (pH ini 6.8–9.0). Besides, FeS 2 in combined-Fe 0 /FeS 2 system could also accelerate the reactions between Fe 0 to O 2 at pH ini 3.0–9.0. These phenomena were well explained by a galvanic couple between Fe 0 and FeS 2 , where FeS 2 was a cathode and Fe 0 was an anode. Consequently, electrons released from Fe 0 that mediated by FeS 2 to oxide film, passivation layer and O 2 were accelerated in combined-Fe 0 /FeS 2 system and thereby enhanced the corrosion of Fe 0 for efficient As removal. Our findings suggest that utilizing FeS 2 to enhance the corrosion of Fe 0 would be a promising technology for remediation of As-contaminated water.
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MOLECULES
·
2019
·Vol. 24
·期 7
·1211
·
IF 3.06
Gongsen Chen,Xin Leng,Juyuan Luo,Longtai You,Changhai Qu,Xiaoxv Dong,Hongliang Huang,Xingbin Yin,Jian Ni
A MIL series metal‒organic framework (MOF), MIL-100(Fe), was successfully synthesized at the nanoscale and fully characterized by TEM, TGA, XRD, FTIR, DLS, and BET. A toxicological assessment was performed using two different cell lines: human normal liver cells (HL-7702) and hepatocellular carcinoma (HepG2). In vitro cytotoxicity of MIL-100(Fe) was evaluated by the MTT assay, LDH releasing rate assay, DAPI staining, and annexin V/PI double staining assay. The safe dose of MIL-100(Fe) was 80 μg/mL. It exhibited good biocompatibility, low cytotoxicity, and high cell survival rate (HL-7702 cells’ viability >85.97%, HepG2 cells’ viability >91.20%). Therefore, MIL-100(Fe) has a potential application as a drug carrier.Keywords:MIL-100(Fe);in vitro toxicity;HL-7702 cells;HepG2 cells
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RSC Advances
·
2019
·Vol. 9
·期 41
·23711-23717
·
IF 3.049
Shu-Hui Huo,Chen-Xu Liu,Peng-Xin Zhou,Jing Yu,Lei Bai,Zhen-Gang Han,Xiao-Quan Lu
Development of novel porous materials for efficient adsorption and removal of environmental pollutants from aqueous solution is of great importance and interest in environmental science and chemistry. Herein, we reported a facile synthesis of recyclable magnetic carbonaceous porous composite derived from iron-based metal–organic framework MIL-100(Fe) for superior adsorption and removal of malachite green (MG) from aqueous solution. Because of large surface area and high porosity, the synthesized magnetic carbonaceous porous material presented a superior adsorption capacity of 2090 mg g−1 for MG. The adsorption of MG on magnetic carbonaceous porous composite is endothermic and spontaneous. The prepared magnetic carbonaceous porous composite could be separated easily and rapidly from the solution matrix by an external magnet. The rapid adsorption, large adsorption capacity and good reusability make it attractive for practical use in the adsorption and removal of dyes from aqueous solutions.
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CELLULOSE
·
2019
·Vol. 26
·期 11
·6813-6823
·
IF 3.917
Li Shusheng,Yang Shanshan,Zhu Xiaoli,Jiang Xubao,Kong Xiang Zheng
Owing to the increasing amount of industrial wastewater and ocean pollution, separation of water and oil from their mixtures and emulsions has been an active area in water treatment industry and in academic research. Using cellulose filter paper as the substrate, a porous superoleophobic membrane (OP) was easily prepared by immersing the paper in an acetonitrile solution of toluene diisocyanate and that of N -(2,4-diaminophenyl) maleimide, alternatively and repeatedly, coating the paper with maleimide-containing polyurea (PU). PU coated paper was then functionalized by 2-[(tris(hydroxymethyl)methyl)amino]-1-ethanesulfonic acid through aza-Michael addition. The formation of PU coating and the subsequent functionalization were confirmed by FTIR, NMR and XPS analyses. The produced OP paper was shown to be superoleophobic and had excellent performance for oil–water separation from their mixtures and emulsions. This study provides therefore a novel protocol for preparation of superoleophobic materials, featuring easy operation, low cost, and in particular, versatile applicability to different natural and synthetic materials.
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MICROCHIMICA ACTA
·
2019
·Vol. 187
·期 1
·1-9
·
IF 5.479
Zhang Wanqing,Fan Shumin,Li Xinli,Liu Shanqin,Duan Dawei,Leng Leipeng,Cui Chengxing,Zhang Yuping,Qu Lingbo
A glassy carbon electrode (GCE) was modified with a composite prepared from phytic acid, polypyrrole and a ZIF type metal-organic framework (PA/PPy)/ZIF-8@ZIF-67). The nanocomposite was prepared by in-situ chemical polymerization in the presence of ferric chloride and subsequently functionalized with PA to form PA/PPy/ZIF-8@ZIF-67. The materials were characterized by XRD, FT-IR, BET, XPS, SEM and TEM. The modified GCE was applied to individual and simultaneous detection of Pb(II) and Cu(II), with peak voltages of −0.6 and − 0.1 V, respectively (vs. SCE). The amount of PPy, the ZIF-8@ZIF-67 concentration, polymerization potential, polymerization time and pH value were optimized. Under optimized conditions, the calibration plots have two linear ranges. These are from 0.02 to 200 μM and from 200 to 600 μM for Pb(II), and from 0.2 to 200 μM and 200 to 600 μM for Cu(II). The detection limits are 2.9 nM and 14.8 nM, respectively. Simultaneous detection of Pb(II) and Cu(II) is also demonstrated. The good performance of the electrode is attributed to the large surface area of ZIF-8@ZIF-67, the good electrical conductivity of PPy, and the metal complexation power of PA. The modified GCE was successfully applied to the determination of Pb(II) and Cu(II) in real samples and gave satisfactory recoveries.
Schematic presentation of the construction process of PA/PPy/ZIF-8@ZIF-67/GCE sensor, and the mechanism of Pb(II) and Cu(II) at the prepared sensor.
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