To remove the fluoride in zinc sulfate electrolyte to an appropriate level,mitigate environmental fluoride pollution,and drive the development of the hydrometallurgy industry of zinc,a novel Fe_(3)O_(4)@SiO_(2)@Fe-MIL...To remove the fluoride in zinc sulfate electrolyte to an appropriate level,mitigate environmental fluoride pollution,and drive the development of the hydrometallurgy industry of zinc,a novel Fe_(3)O_(4)@SiO_(2)@Fe-MIL-101 magnetic composite material was successfully synthesized via the one-pot method.Preparation conditions were optimized and structural characterization of this material conducted using FTIR,SEM,EDS,XRD and Hysteresis analysis.The results show that this composite exhibits a more rapid fluoride adsorption dynamics and a higher fluoride adsorption capacity(18.34 mg/g)and its adsorption behavior fitted for the first order dynamic model and the Freundlich isotherm model.The adsorption of fluorine by this composite is mainly physical adsorption according to the mean adsorption energy(1.216 kJ/mol).The interfering ions co-existed in fluoride-containing solutions,like HCO_(3)^(-),NO^(-)and Cl^(-),have a significant effect on fluorine adsorption.This composite has also been proved with magnetism,higher adsorption selectivity and satisfactory reusability.When this composite is employed as an adsorbent for adsorption removing fluoride in zinc sulfate electrolyte,it exhibits higher pH-dependent behavior as well as high fluoride removal efficiency at pH 6.5.展开更多
Ferromagnetic Fe3O4 nanoparticles were synthesized using water as the solvent through the sol-gel method, which was selected for its cost-effectiveness, simplicity, and eco-friendly nature. The synthesized nanoparticl...Ferromagnetic Fe3O4 nanoparticles were synthesized using water as the solvent through the sol-gel method, which was selected for its cost-effectiveness, simplicity, and eco-friendly nature. The synthesized nanoparticles were characterized using a variety of techniques, including Fourier Transform Infrared (FTIR) spectroscopy, X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), and Vibrating Sample Magnetometer (VSM). These characterizations confirmed the successful formation of Fe3O4 nanoparticles. The FTIR spectra identified characteristic peaks corresponding to the functional groups present, and XRD analysis, using Scherer’s equation, determined an average crystalline size of 1.2 nm for the Fe3O4 nanoparticles. TGA results demonstrated the thermal stability of the nanoparticles, SEM imaging revealed distinct honeycomb-like structures for the nanoparticles synthesized with water as the solvent, while the VSM analysis was used to determine the magnetic behavior of the nanoparticles.展开更多
The problem of water and sulfur poisoning in flue gas atmosphere remains a significant obstacle for low-temperature deNO_(x) catalysts.This study investigated the sulfation mechanism of the CoMn_(2)O_(4)/CeTiO_(x)(CMC...The problem of water and sulfur poisoning in flue gas atmosphere remains a significant obstacle for low-temperature deNO_(x) catalysts.This study investigated the sulfation mechanism of the CoMn_(2)O_(4)/CeTiO_(x)(CMCT)catalyst during the selective catalytic reduction of NO_(x) with NH3 under conditions containing H2O and SO_(2) at 150℃.Employing a comprehensive suite of time-resolved analysis and characterization techniques,the evolution of sulfate species was systematically categorized into three stages:initial rapid surface sulfate accumulation,the transformation of surface sulfates to bulk metal sulfates,and partial sulfates decomposition after the removal of H2O and SO_(2).These findings indicate that bulk metal sulfates irreversibly deactivate the catalyst by distorting active component lattices and consuming oxygen vacancies,whereas surface sulfates(including ammonium sulfates and surface-coordinated metal sulfates)cause reversible performance loss through decomposition.Furthermore,the competitive adsorption of H2O and SO_(2) significantly influences the catalytic efficiency,with H2O suppressing SO_(2) adsorption while simultaneously enhancing the formation of Brönsted acid sites.This research underscores the critical role of sulfate dynamics on catalyst performance,revealing the enhanced SO_(2) resistance of the Eley-Rideal mechanism facilitated by the Ce-Ti support relative to the Langmuir-Hinshelwood pathway.Collectively,the study unravels the complex interplay of sulfate dynamics influencing catalyst performance and provides potential approaches to mitigate deactivation in demanding atmospheric conditions.展开更多
Regulating the orbital spin-electron filling of metal centers via interatomic electron transfer in transition metal oxides is one promising approach to enhancing their electrocatalytic oxygen evolution reaction(OER)pe...Regulating the orbital spin-electron filling of metal centers via interatomic electron transfer in transition metal oxides is one promising approach to enhancing their electrocatalytic oxygen evolution reaction(OER)performances,while it is still a challenge due to lacking of efficient strategy and deep understanding.In this work,a facile strategy containing electrochemical deposition and annealing in air atmosphere has been proposed to introduce monodispersed neodymium(Nd)atoms into spinel Co_(3)O_(4)nanosheets to trigger the electron transfer.Accordingly,the as-prepared Nd doped Co_(3)O_(4)nanosheets(Nd/Co_(3)O_(4))on nickel foam or carbon cloth showed greatly enhanced OER performances,with low overpotential of 284 and 396 mV at 10 m A cm^(-2),small Tafel slope of 95 and 119 mV dec^(-1)in 1.0 M KOH and 0.5 M H_(2)SO_(4),respectively.The experimental and density function theory results coherently indicate that the charge transfer in the Nd-O-Co asymmetric configuration not only enhances the conductivity of Co_(3)O_(4),but also regulates the filling degree of egorbitals of Co,leading to higher spin states,optimized adsorption ability,and accelerated H_(2)O dissociation process,thus achieving boosted OER activity.展开更多
Here we report that the presence of MgCO_(3) stimulates the extracellular polymeric substance (EPS) secretion of Microcystis Aeruginosa (M. Aeruginosa). This stimulation led to a significant reduction in the total con...Here we report that the presence of MgCO_(3) stimulates the extracellular polymeric substance (EPS) secretion of Microcystis Aeruginosa (M. Aeruginosa). This stimulation led to a significant reduction in the total concentration of NH_(4)^(+)‒N by more than 86%, and effective recovery of PO_(4)^(3-)‒P within three days from concentrated wastewater (WW), although the secreted EPS inhibited the conversion of MgCO_(3) to specific crystal forms (MgNH4PO4.6H2O or MgHPO4.7H2O). Moreover, with an increase in PO_(4)^(3-) concentration in WW, these crystals appeared, thus the removal of NH_(4)^(+)‒N and PO_(4)^(3-)‒P nutrients can be attributed to the combined effect of M. Aeruginosa and MgCO_(3). We used Surface-Enhanced Raman Spectroscopy (SERS) combined with X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy with Energy-Dispersive X-ray Spectroscopy (FESEM-EDS), and X-ray Photoelectron Spectroscopy (XPS) to investigate the mechanism for competitive interactions between M. Aeruginosa and MgCO_(3) in removing NH_(4)^(+)‒N and PO_(4)^(3-)‒P. We identified that the bound EPS accumulated amorphous Mg–P–O dense particles on M. Aeruginosa, while soluble EPS, containing –COOH groups of humic-like substances decreased the pH of the solution and coordinated with Mg^(2+) ions. Therefore, both secreted bound and soluble EPS play a vital role in hindering the transformation of Mg^(2+) ions or MgCO_(3) to MgNH4PO4.6H2O or MgHPO4.7H2O crystals within WW, and they enhanced M. Aeruginosa 's ability in absorbing nutrients of NH_(4)^(+)‒N and PO_(4)^(3-)‒P. This mechanism plays a crucial role in the efficient recovery of NH_(4)^(+)‒N and PO_(4)^(3-)‒P from concentrated wastewater sources such as aerobically or anaerobically digested effluent from various sources like agriculture, livestock, and domestic wastewaters.展开更多
采用溶胶-凝胶法制备Fe_3O_4/TiO_2异质磁性催化剂,通过性能流损平衡测试筛选得到最优催化剂Fe_3O_4含量为20%,热处理温度300℃,并对催化剂进行了多手段表征。以罗丹明B为模型污染物,考察催化剂用量、电导率、温度、pH值、复用稳定性的...采用溶胶-凝胶法制备Fe_3O_4/TiO_2异质磁性催化剂,通过性能流损平衡测试筛选得到最优催化剂Fe_3O_4含量为20%,热处理温度300℃,并对催化剂进行了多手段表征。以罗丹明B为模型污染物,考察催化剂用量、电导率、温度、pH值、复用稳定性的影响。试验结果表明,催化光降解浓度为1×10^(-5)mol/L罗丹明B,电导率为50 m S/cm、温度为30℃、p H值为6、催化剂投加量0.1 g/50 m L,150 min时罗丹明B降解率达到94.6%。展开更多
基金National Natural Science Foundation of China(21865011)2024 Innovation and Entrepreneurship Project of College Student in Jishou University(JDCX20241122)。
文摘To remove the fluoride in zinc sulfate electrolyte to an appropriate level,mitigate environmental fluoride pollution,and drive the development of the hydrometallurgy industry of zinc,a novel Fe_(3)O_(4)@SiO_(2)@Fe-MIL-101 magnetic composite material was successfully synthesized via the one-pot method.Preparation conditions were optimized and structural characterization of this material conducted using FTIR,SEM,EDS,XRD and Hysteresis analysis.The results show that this composite exhibits a more rapid fluoride adsorption dynamics and a higher fluoride adsorption capacity(18.34 mg/g)and its adsorption behavior fitted for the first order dynamic model and the Freundlich isotherm model.The adsorption of fluorine by this composite is mainly physical adsorption according to the mean adsorption energy(1.216 kJ/mol).The interfering ions co-existed in fluoride-containing solutions,like HCO_(3)^(-),NO^(-)and Cl^(-),have a significant effect on fluorine adsorption.This composite has also been proved with magnetism,higher adsorption selectivity and satisfactory reusability.When this composite is employed as an adsorbent for adsorption removing fluoride in zinc sulfate electrolyte,it exhibits higher pH-dependent behavior as well as high fluoride removal efficiency at pH 6.5.
文摘Ferromagnetic Fe3O4 nanoparticles were synthesized using water as the solvent through the sol-gel method, which was selected for its cost-effectiveness, simplicity, and eco-friendly nature. The synthesized nanoparticles were characterized using a variety of techniques, including Fourier Transform Infrared (FTIR) spectroscopy, X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), and Vibrating Sample Magnetometer (VSM). These characterizations confirmed the successful formation of Fe3O4 nanoparticles. The FTIR spectra identified characteristic peaks corresponding to the functional groups present, and XRD analysis, using Scherer’s equation, determined an average crystalline size of 1.2 nm for the Fe3O4 nanoparticles. TGA results demonstrated the thermal stability of the nanoparticles, SEM imaging revealed distinct honeycomb-like structures for the nanoparticles synthesized with water as the solvent, while the VSM analysis was used to determine the magnetic behavior of the nanoparticles.
文摘The problem of water and sulfur poisoning in flue gas atmosphere remains a significant obstacle for low-temperature deNO_(x) catalysts.This study investigated the sulfation mechanism of the CoMn_(2)O_(4)/CeTiO_(x)(CMCT)catalyst during the selective catalytic reduction of NO_(x) with NH3 under conditions containing H2O and SO_(2) at 150℃.Employing a comprehensive suite of time-resolved analysis and characterization techniques,the evolution of sulfate species was systematically categorized into three stages:initial rapid surface sulfate accumulation,the transformation of surface sulfates to bulk metal sulfates,and partial sulfates decomposition after the removal of H2O and SO_(2).These findings indicate that bulk metal sulfates irreversibly deactivate the catalyst by distorting active component lattices and consuming oxygen vacancies,whereas surface sulfates(including ammonium sulfates and surface-coordinated metal sulfates)cause reversible performance loss through decomposition.Furthermore,the competitive adsorption of H2O and SO_(2) significantly influences the catalytic efficiency,with H2O suppressing SO_(2) adsorption while simultaneously enhancing the formation of Brönsted acid sites.This research underscores the critical role of sulfate dynamics on catalyst performance,revealing the enhanced SO_(2) resistance of the Eley-Rideal mechanism facilitated by the Ce-Ti support relative to the Langmuir-Hinshelwood pathway.Collectively,the study unravels the complex interplay of sulfate dynamics influencing catalyst performance and provides potential approaches to mitigate deactivation in demanding atmospheric conditions.
基金support from the Natural Science Foundation and Overseas Talent Projects of Jiangxi Province(20242BAB25217,20232BAB214025,20232BCJ25044)the Jiangxi Provincial Natural Science Foundation(20232BAB204088)the National Natural Science Foundation of China(52402132)。
文摘Regulating the orbital spin-electron filling of metal centers via interatomic electron transfer in transition metal oxides is one promising approach to enhancing their electrocatalytic oxygen evolution reaction(OER)performances,while it is still a challenge due to lacking of efficient strategy and deep understanding.In this work,a facile strategy containing electrochemical deposition and annealing in air atmosphere has been proposed to introduce monodispersed neodymium(Nd)atoms into spinel Co_(3)O_(4)nanosheets to trigger the electron transfer.Accordingly,the as-prepared Nd doped Co_(3)O_(4)nanosheets(Nd/Co_(3)O_(4))on nickel foam or carbon cloth showed greatly enhanced OER performances,with low overpotential of 284 and 396 mV at 10 m A cm^(-2),small Tafel slope of 95 and 119 mV dec^(-1)in 1.0 M KOH and 0.5 M H_(2)SO_(4),respectively.The experimental and density function theory results coherently indicate that the charge transfer in the Nd-O-Co asymmetric configuration not only enhances the conductivity of Co_(3)O_(4),but also regulates the filling degree of egorbitals of Co,leading to higher spin states,optimized adsorption ability,and accelerated H_(2)O dissociation process,thus achieving boosted OER activity.
基金supported by Cultivating Fund Project of Hubei Hongshan Laboratory(2022hspy002).
文摘Here we report that the presence of MgCO_(3) stimulates the extracellular polymeric substance (EPS) secretion of Microcystis Aeruginosa (M. Aeruginosa). This stimulation led to a significant reduction in the total concentration of NH_(4)^(+)‒N by more than 86%, and effective recovery of PO_(4)^(3-)‒P within three days from concentrated wastewater (WW), although the secreted EPS inhibited the conversion of MgCO_(3) to specific crystal forms (MgNH4PO4.6H2O or MgHPO4.7H2O). Moreover, with an increase in PO_(4)^(3-) concentration in WW, these crystals appeared, thus the removal of NH_(4)^(+)‒N and PO_(4)^(3-)‒P nutrients can be attributed to the combined effect of M. Aeruginosa and MgCO_(3). We used Surface-Enhanced Raman Spectroscopy (SERS) combined with X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy with Energy-Dispersive X-ray Spectroscopy (FESEM-EDS), and X-ray Photoelectron Spectroscopy (XPS) to investigate the mechanism for competitive interactions between M. Aeruginosa and MgCO_(3) in removing NH_(4)^(+)‒N and PO_(4)^(3-)‒P. We identified that the bound EPS accumulated amorphous Mg–P–O dense particles on M. Aeruginosa, while soluble EPS, containing –COOH groups of humic-like substances decreased the pH of the solution and coordinated with Mg^(2+) ions. Therefore, both secreted bound and soluble EPS play a vital role in hindering the transformation of Mg^(2+) ions or MgCO_(3) to MgNH4PO4.6H2O or MgHPO4.7H2O crystals within WW, and they enhanced M. Aeruginosa 's ability in absorbing nutrients of NH_(4)^(+)‒N and PO_(4)^(3-)‒P. This mechanism plays a crucial role in the efficient recovery of NH_(4)^(+)‒N and PO_(4)^(3-)‒P from concentrated wastewater sources such as aerobically or anaerobically digested effluent from various sources like agriculture, livestock, and domestic wastewaters.
文摘采用溶胶-凝胶法制备Fe_3O_4/TiO_2异质磁性催化剂,通过性能流损平衡测试筛选得到最优催化剂Fe_3O_4含量为20%,热处理温度300℃,并对催化剂进行了多手段表征。以罗丹明B为模型污染物,考察催化剂用量、电导率、温度、pH值、复用稳定性的影响。试验结果表明,催化光降解浓度为1×10^(-5)mol/L罗丹明B,电导率为50 m S/cm、温度为30℃、p H值为6、催化剂投加量0.1 g/50 m L,150 min时罗丹明B降解率达到94.6%。
