为了提升大豆蛋白废水厌氧发酵产气性能,通过批式实验探究纳米Fe3O4(Fe3O4nanoparticles,Fe3O4NPs)对模拟大豆蛋白废水厌氧发酵产甲烷的影响,并采用2种不同模型对发酵过程中累积甲烷产量进行动力学分析。结果表明,添加适量的Fe3O4NPs有...为了提升大豆蛋白废水厌氧发酵产气性能,通过批式实验探究纳米Fe3O4(Fe3O4nanoparticles,Fe3O4NPs)对模拟大豆蛋白废水厌氧发酵产甲烷的影响,并采用2种不同模型对发酵过程中累积甲烷产量进行动力学分析。结果表明,添加适量的Fe3O4NPs有助于提高大豆蛋白废水厌氧发酵产气量和有机物去除率,促进产甲烷过程。质量浓度为300 mg/L时,累积产气量达到652.12 m L,比对照组提高23.51%,平均甲烷含量为81.63%;可溶性化学需氧量(soluble chemical oxygen demand,SCOD)、生化需氧量(biochemical oxygen demand,BOD5)和蛋白质去除率均最高,分别为89.11%、91.91%和71.52%,甲烷产率达到331.40 m L/g SCOD;添加Fe3O4NPs可以降低厌氧发酵过程中氨氮和总氮浓度。Transference模型和改进的Gompertz模型均可较好地拟合大豆蛋白废水厌氧发酵产甲烷过程,前者拟合度更高(R2>0.96),且Fe3O4NPs质量浓度为300 mg/L时获得的最大甲烷产率为350.84 m L/g SCOD。展开更多
Enrichment of trace bioactive constituents and metabolites from complex biological samples is challenging.This study presented a one-pot synthesis of magnetic polydopamine nanoparticles(Fe3O4@-SiO2@PDA NPs)with multip...Enrichment of trace bioactive constituents and metabolites from complex biological samples is challenging.This study presented a one-pot synthesis of magnetic polydopamine nanoparticles(Fe3O4@-SiO2@PDA NPs)with multiple recognition sites for the magnetic dispersive solid-phase extraction(MDSPE)of ginsenosides from rat plasma treated with white ginseng.The extracted ginsenosides were characterized by combining an ultra-high-performance liquid chromatography coupled to a highresolution mass spectrometry with supplemental UNIFI libraries.Response surface methodology was statistically used to optimize the extraction procedure of the ginsenosides.The reusability of Fe3O4@-SiO2@PDA NPs was also examined and the results showed that the recovery rate exceeded 80%after recycling 6 times.Furthermore,the proposed method showed greater enrichment efficiency and could rapidly determine and characterize 23 ginsenoside prototypes and metabolites from plasma.In comparison,conventional methanol method can only detect 8 ginsenosides from the same plasma samples.The proposed approach can provide methodological reference for the trace determination and characterization of different bioactive ingredients and metabolites of traditional Chinese medicines and food.展开更多
In situ anchor of magnetic Fe304 nanoparticles （NPs） onto the surface of natural maifanite was realized by chemical oxidation coprecipitation in hot alkaline solution. The Fe304/maifanite composites were characteriz...In situ anchor of magnetic Fe304 nanoparticles （NPs） onto the surface of natural maifanite was realized by chemical oxidation coprecipitation in hot alkaline solution. The Fe304/maifanite composites were characterized by XRD, FTIR, SEM, and TEM. These results indicated that polycrystalline Fe304 NPs with inverse spinel structure were formed and tightly dispersed on maifanite surface. Based on the measurement of surface Zeta potential of maifanite at different medium pHs, the possible combination mechanism between natural maifanite and Fe304 NPs was proposed. Then, the as- obtained composites were developed as highly efficient heterogeneous Fenton-like catalyst for the discoloration of an azo dye, Methyl Orange （MO）. The comparative tests on MO discoloration in different systems revealed that Fe304/maifanite composite exhibited much higher Fenton-like catalytic activity than Fe304 NPs and the heterogeneous Fenton- like reaction governed the discoloration of MO. Kinetic results clearly showed that MO discoloration process followed the second-order kinetic model. Fe304/maifanite compo- sites exhibited the typical ferromagnetic property detected by VSM and could be easily separated from solution by an external magnetic field.展开更多
Multi-walled carbon nanotubes （MWCNTs） can act not only as a support for Fe3O4 nanoparticles （NPs） but also as a coworker with synergistic effect, accordingly improving the heterogeneous Fenton-like efficiency of ...Multi-walled carbon nanotubes （MWCNTs） can act not only as a support for Fe3O4 nanoparticles （NPs） but also as a coworker with synergistic effect, accordingly improving the heterogeneous Fenton-like efficiency of Fe3O4 NPs. In this study, Fe3O4 NPs were in situ anchored onto MWCNTs by a moderate co-precipitation method and the as-prepared Fe3O4/MWCNTs nanocomposites were employed as the highly efficient Fenton-like catalysts. The analyses of XRD, FTIR, Raman, FESEM, TEM and HRTEM results indicated the formation of Fe3O4 crystals in Fe3O4/MWCNTs nanocomposites prepared at different conditions and the interaction between Fe3O4 NPs and MWCNTs. Over a wide pH range, the surface of modified MWCNTs possessed negative charges. Based on these results, the possible combination mechanism between Fe3O4 NPs and MWCNTs was discussed and proposed. Moreover, the effects of preparation and catalytic conditions on the Fenton-like catalytic efficiency were investigated in order to gain further insight into the heterogeneous Fenton-like reaction catalyzed by Fe3O4/MWCNTs nanocomposites.展开更多
The kinetics and Fenton-like mechanism are two challenging tasks for heterogeneous Fenton-like catalytic oxidation of organic pollutants. In this study, three kinetic models were used for the kinetic studies of Fe3O4/...The kinetics and Fenton-like mechanism are two challenging tasks for heterogeneous Fenton-like catalytic oxidation of organic pollutants. In this study, three kinetic models were used for the kinetic studies of Fe3O4/MWCNTs-H2O2 Fenton-like reaction for MO degradation. The results indicated that this reaction followed the first- order kinetic model. The relationship of reaction rate constant and temperature followed the Arrhenius equation. The activation energy and frequency factor of this system were calculated as 8.2 kJ.mo1-1 and 2.72 s-1, respectively. The quantifications of Fe ions dissolution and ,OH radicals generation confirmed that the homogeneous and hetero- geneous catalyses were involved in Fe3O4/MWCNTs＇H2O2 Fenton-like reaction. The reaction rate constant was closely related with Fe ions dissolution and ,OH radicals generation. Fe3O4/MWCNTs nanocomposites had typical ferromagnetic property and could be easily separated from solution by an external magnet after being used. Furthermore, Fe3O4/MWCNTs nanocomposites exhibited good stability and recyclability. Finally, the Fenton-like mechanisms on homogeneous and heterogeneous catalyses were described.展开更多
To assess the biological safety of Fe3O4 nanoparticles （NPs）, the oxidative-damage effect of these NPs was studied. Twenty-five Kunming mice were exposed to Fe3O4 NPs by intraperitoneai injection daily for 1 week at...To assess the biological safety of Fe3O4 nanoparticles （NPs）, the oxidative-damage effect of these NPs was studied. Twenty-five Kunming mice were exposed to Fe3O4 NPs by intraperitoneai injection daily for 1 week at doses of 0, 10, 20, and 40 mg.kg1. Five Kunming mice were also injected with 40 mg.kg 1 ordinary Fe3O4 particles under the same physiological conditions. Biomarkers of reactive oxygen species （ROS）, glutathione （GSH）, and malondialdehyde （MDA） in the hepatic and brain tissues were detected. Results showed that no significant difference in oxidative damage existed at concentrations lower than 10 mg.kg i for NPs compared with the control group. Fe3O4 NP concentration had obvious dose-effect relationships （P〈 0.05 or P 〈 0.01） with ROS level, GSH content, and MDA content in mouse hepatic and brain tissues at〉20 mg.kg 1 concentrations. To some extent, ordinary Fe3O4 particles with 40mg.kg -1 concentration also affected hepatic and brain tissues in mice. The biological effect was similar to Fe3O4 NPs at 10 mg. kg-1 concentration. Thus, Fe3O4 NPs had significant damage effects on the antioxidant defense system in the hepatic and brain tissues of mice, whereas ordinary Fe3O4 had less influence than Fe3O4 NPs at the same concentration.展开更多
Novel magnetic core/shell bimetallic Au/Cu nanoparticles（Fe_3O_4@SiO_2-Au/Cu NPs） were prepared using SiO_2-coated iron oxide（Fe_3O_4@SiO_2） as a supported material. The magnetic Fe_3O_4 colloidal nanocrystal clus...Novel magnetic core/shell bimetallic Au/Cu nanoparticles（Fe_3O_4@SiO_2-Au/Cu NPs） were prepared using SiO_2-coated iron oxide（Fe_3O_4@SiO_2） as a supported material. The magnetic Fe_3O_4 colloidal nanocrystal clusters（CNCs） as nano-core were modified with a silica coating for improvement stability and superficial area of the Au-Cu particles. The morphological structure and chemical composition of the Fe_3O_4@SiO_2-Au/Cu NPs were characterized with high-resolution transmission electron microscopy（HRTEM）, energy-dispersive X-ray（EDX） and X-ray photoelectron spectroscopy（XPS） analyses. The Au and Cu NPs were deposited on the SiO_2 surface in a highly dense and well dispersed manner with an average size of approximately 5 nm. The Fe_3O_4@SiO_2-Au/Cu NPs as magnetic nano-catalysts were applied to the Ullmann coupling reaction of bromamine acid to synthesize 4,40-diamino-1,10-dianthraquinonyl-3,30-disulfonic acid（DAS）. The prepared Fe_3O_4@SiO_2-Au/Cu NPs exhibited efficient catalytic activity with higher conversion and selectivity. A bromamine acid conversion of 97.35% and selectivity for DAS of 88.67% were obtained in aqueous medium. The magnetic nano-catalysts can be readily separated from the reaction system and reused. This new nano-catalytic reaction represents a useful and attractive cleaner production system. The new catalyst system has important and potential applications in dye and pigment industry.展开更多
文摘为了提升大豆蛋白废水厌氧发酵产气性能,通过批式实验探究纳米Fe3O4(Fe3O4nanoparticles,Fe3O4NPs)对模拟大豆蛋白废水厌氧发酵产甲烷的影响,并采用2种不同模型对发酵过程中累积甲烷产量进行动力学分析。结果表明,添加适量的Fe3O4NPs有助于提高大豆蛋白废水厌氧发酵产气量和有机物去除率,促进产甲烷过程。质量浓度为300 mg/L时,累积产气量达到652.12 m L,比对照组提高23.51%,平均甲烷含量为81.63%;可溶性化学需氧量(soluble chemical oxygen demand,SCOD)、生化需氧量(biochemical oxygen demand,BOD5)和蛋白质去除率均最高,分别为89.11%、91.91%和71.52%,甲烷产率达到331.40 m L/g SCOD;添加Fe3O4NPs可以降低厌氧发酵过程中氨氮和总氮浓度。Transference模型和改进的Gompertz模型均可较好地拟合大豆蛋白废水厌氧发酵产甲烷过程,前者拟合度更高(R2>0.96),且Fe3O4NPs质量浓度为300 mg/L时获得的最大甲烷产率为350.84 m L/g SCOD。
基金This work was supported by grants from the National Natural Science Foundation of China Key Program(NO.81530094)General Program(NO.81573574,81873193)the Science and Technology Development Project of Jilin Province(20190201283JC).
文摘Enrichment of trace bioactive constituents and metabolites from complex biological samples is challenging.This study presented a one-pot synthesis of magnetic polydopamine nanoparticles(Fe3O4@-SiO2@PDA NPs)with multiple recognition sites for the magnetic dispersive solid-phase extraction(MDSPE)of ginsenosides from rat plasma treated with white ginseng.The extracted ginsenosides were characterized by combining an ultra-high-performance liquid chromatography coupled to a highresolution mass spectrometry with supplemental UNIFI libraries.Response surface methodology was statistically used to optimize the extraction procedure of the ginsenosides.The reusability of Fe3O4@-SiO2@PDA NPs was also examined and the results showed that the recovery rate exceeded 80%after recycling 6 times.Furthermore,the proposed method showed greater enrichment efficiency and could rapidly determine and characterize 23 ginsenoside prototypes and metabolites from plasma.In comparison,conventional methanol method can only detect 8 ginsenosides from the same plasma samples.The proposed approach can provide methodological reference for the trace determination and characterization of different bioactive ingredients and metabolites of traditional Chinese medicines and food.
基金This work was financially supported by the National Natural Science Foundation of China （Grant No. 51404083）, the Program for New Century Excellent Talents in Heilongjiang Provincial Universities （Grant No. 1253-NCET-010）, the Research Development Fund of Nianzishan Institute of Maifanite, Qiqihaer （Grant No. 201406）, and the Natural Science Foundation of Heilongjiang Province, China （Grant No. E2015065）.
文摘In situ anchor of magnetic Fe304 nanoparticles （NPs） onto the surface of natural maifanite was realized by chemical oxidation coprecipitation in hot alkaline solution. The Fe304/maifanite composites were characterized by XRD, FTIR, SEM, and TEM. These results indicated that polycrystalline Fe304 NPs with inverse spinel structure were formed and tightly dispersed on maifanite surface. Based on the measurement of surface Zeta potential of maifanite at different medium pHs, the possible combination mechanism between natural maifanite and Fe304 NPs was proposed. Then, the as- obtained composites were developed as highly efficient heterogeneous Fenton-like catalyst for the discoloration of an azo dye, Methyl Orange （MO）. The comparative tests on MO discoloration in different systems revealed that Fe304/maifanite composite exhibited much higher Fenton-like catalytic activity than Fe304 NPs and the heterogeneous Fenton- like reaction governed the discoloration of MO. Kinetic results clearly showed that MO discoloration process followed the second-order kinetic model. Fe304/maifanite compo- sites exhibited the typical ferromagnetic property detected by VSM and could be easily separated from solution by an external magnetic field.
基金This work was financially supported by the Natural Science Foundation of Heilongjiang Province, China （No. E2015065）.
文摘Multi-walled carbon nanotubes （MWCNTs） can act not only as a support for Fe3O4 nanoparticles （NPs） but also as a coworker with synergistic effect, accordingly improving the heterogeneous Fenton-like efficiency of Fe3O4 NPs. In this study, Fe3O4 NPs were in situ anchored onto MWCNTs by a moderate co-precipitation method and the as-prepared Fe3O4/MWCNTs nanocomposites were employed as the highly efficient Fenton-like catalysts. The analyses of XRD, FTIR, Raman, FESEM, TEM and HRTEM results indicated the formation of Fe3O4 crystals in Fe3O4/MWCNTs nanocomposites prepared at different conditions and the interaction between Fe3O4 NPs and MWCNTs. Over a wide pH range, the surface of modified MWCNTs possessed negative charges. Based on these results, the possible combination mechanism between Fe3O4 NPs and MWCNTs was discussed and proposed. Moreover, the effects of preparation and catalytic conditions on the Fenton-like catalytic efficiency were investigated in order to gain further insight into the heterogeneous Fenton-like reaction catalyzed by Fe3O4/MWCNTs nanocomposites.
基金This work was financially supported by the Natural Science Foundation of Heilongjiang Province, China （Grant No. E2015065）.
文摘The kinetics and Fenton-like mechanism are two challenging tasks for heterogeneous Fenton-like catalytic oxidation of organic pollutants. In this study, three kinetic models were used for the kinetic studies of Fe3O4/MWCNTs-H2O2 Fenton-like reaction for MO degradation. The results indicated that this reaction followed the first- order kinetic model. The relationship of reaction rate constant and temperature followed the Arrhenius equation. The activation energy and frequency factor of this system were calculated as 8.2 kJ.mo1-1 and 2.72 s-1, respectively. The quantifications of Fe ions dissolution and ,OH radicals generation confirmed that the homogeneous and hetero- geneous catalyses were involved in Fe3O4/MWCNTs＇H2O2 Fenton-like reaction. The reaction rate constant was closely related with Fe ions dissolution and ,OH radicals generation. Fe3O4/MWCNTs nanocomposites had typical ferromagnetic property and could be easily separated from solution by an external magnet after being used. Furthermore, Fe3O4/MWCNTs nanocomposites exhibited good stability and recyclability. Finally, the Fenton-like mechanisms on homogeneous and heterogeneous catalyses were described.
基金This work was financially supported by a grant from the National Natural Science Foundation of China （Grant No. 50802032）.
文摘To assess the biological safety of Fe3O4 nanoparticles （NPs）, the oxidative-damage effect of these NPs was studied. Twenty-five Kunming mice were exposed to Fe3O4 NPs by intraperitoneai injection daily for 1 week at doses of 0, 10, 20, and 40 mg.kg1. Five Kunming mice were also injected with 40 mg.kg 1 ordinary Fe3O4 particles under the same physiological conditions. Biomarkers of reactive oxygen species （ROS）, glutathione （GSH）, and malondialdehyde （MDA） in the hepatic and brain tissues were detected. Results showed that no significant difference in oxidative damage existed at concentrations lower than 10 mg.kg i for NPs compared with the control group. Fe3O4 NP concentration had obvious dose-effect relationships （P〈 0.05 or P 〈 0.01） with ROS level, GSH content, and MDA content in mouse hepatic and brain tissues at〉20 mg.kg 1 concentrations. To some extent, ordinary Fe3O4 particles with 40mg.kg -1 concentration also affected hepatic and brain tissues in mice. The biological effect was similar to Fe3O4 NPs at 10 mg. kg-1 concentration. Thus, Fe3O4 NPs had significant damage effects on the antioxidant defense system in the hepatic and brain tissues of mice, whereas ordinary Fe3O4 had less influence than Fe3O4 NPs at the same concentration.
基金financially supported by the Shanghai Natural Science Foundation (No. 13ZR1400300)National Key R&D Program of China (No. 2017YFB030900)
文摘Novel magnetic core/shell bimetallic Au/Cu nanoparticles（Fe_3O_4@SiO_2-Au/Cu NPs） were prepared using SiO_2-coated iron oxide（Fe_3O_4@SiO_2） as a supported material. The magnetic Fe_3O_4 colloidal nanocrystal clusters（CNCs） as nano-core were modified with a silica coating for improvement stability and superficial area of the Au-Cu particles. The morphological structure and chemical composition of the Fe_3O_4@SiO_2-Au/Cu NPs were characterized with high-resolution transmission electron microscopy（HRTEM）, energy-dispersive X-ray（EDX） and X-ray photoelectron spectroscopy（XPS） analyses. The Au and Cu NPs were deposited on the SiO_2 surface in a highly dense and well dispersed manner with an average size of approximately 5 nm. The Fe_3O_4@SiO_2-Au/Cu NPs as magnetic nano-catalysts were applied to the Ullmann coupling reaction of bromamine acid to synthesize 4,40-diamino-1,10-dianthraquinonyl-3,30-disulfonic acid（DAS）. The prepared Fe_3O_4@SiO_2-Au/Cu NPs exhibited efficient catalytic activity with higher conversion and selectivity. A bromamine acid conversion of 97.35% and selectivity for DAS of 88.67% were obtained in aqueous medium. The magnetic nano-catalysts can be readily separated from the reaction system and reused. This new nano-catalytic reaction represents a useful and attractive cleaner production system. The new catalyst system has important and potential applications in dye and pigment industry.
