Fe-based solid catalysts in promoting Fenton reaction to generate ·OH radical has drawn much attention,and interestingly,FeOCl was reported to have superior activity compared with the traditional Fe2 O3 catalysts...Fe-based solid catalysts in promoting Fenton reaction to generate ·OH radical has drawn much attention,and interestingly,FeOCl was reported to have superior activity compared with the traditional Fe2 O3 catalysts.However,the mechanism of Fenton reaction on FeOCl and the origin of high activity remain unclear.Herein,by virtue of DFT+ U calculations,the H2 O2 decomposition and conversion mechanism on FeOCl(100)surface were systematically investigated.It is found that on clean FeOCl(100)surface,the exposed[Fe^3+-Fe^3+]sites can hardly break O-O bond of H2 O2 into OH groups,but instead H2 O2 tends to dehydrogenate by the surface lattice O,resulting in a series of side reactions and final conversion into O2,while the left H atoms gradually saturate the surface lattice O and reduce Fe^3+ into Fe^2+.On fully H-covered FeOCl(100),H2O2 can efficiently dissociate at[Fe^2+-Fe^2+]sites into two OH,but OH binds with Fe^2+ so strongly that it cannot desorb as OH radical as easily as that on Fe^3+.Interestingly,FeOCl(100)tends to be partially protonated in the real acid solution,which,along with H2 O2 dehydrogenation,results in the formation of active unit [Fe^2+-Fe^3+].On[Fe^2+-Fe^3+]unit,H2 O2 can easily break its O-O bond and OH at Fe3+ can desorb as OH radical,while the other OH at Fe^2+ couples with the surface H into H2O and finish the catalytic cycle.By comparison,Fe2 O3(012)cannot provide enough [Fe^2+-Fe^3+] active units due to the relative difficulty in H2 O2 dehydrogenation,which accounts for its inferior catalytic efficiency for Fenton reaction.展开更多
The textile industry spreads globally with the challenges of its wastewater treatment,especially dyes,which are difficult to degrade.To improve coagulation-flocculation process in dye wastewater treatment,an intercala...The textile industry spreads globally with the challenges of its wastewater treatment,especially dyes,which are difficult to degrade.To improve coagulation-flocculation process in dye wastewater treatment,an intercalation process was employed to prepare a new efficient coagulant of lithium borohydride-iron oxychloride(LiBH_(4)_FeOCl) in this study.The layered crystal pristine iron oxychloride(FeOCl) material was prepared by chemical gas phase migration.LiBH4 was introduced into the layers of two dimensional(2 D) FeOCl nanosheets by a simple method of liquid phase insertion.The samples were characterized by a field emitting scanning electron microscopy(SEM),a rotating anode X-ray powder diffractometer(XRD),etc.The cationic dye was employed as the simulated pollutant.A coagulation and decolorization experimental device was built to study the coagulation performance of the new coagulant LiBH_(4)_FeOCl.It is found that the intercalation modified LiBH_(4)_FeOCl exhibits the characteristics of crystal structure,and the layered structure of FeOCl is preserved.LiBH_(4)_FeOCl,as an insoluble inorganic solid coagulant,performs well for dye pollutants of methyl red,basic yellow 1,methylene blue,rhodamine B,ethyl violet and Janus green B.The reaction rate is significantly 68% higher than the current commercial coagulants of Al_(2)(SO_(4))_(3).The mechanism analysis reveals that LiBH_(4)_FeOCl breaks and disperses rapidly in the water environment.Its negatively charged material particles can be electrostatically adsorbed with dye pollutant molecules through electrostatic action.The above collaborative actions of breaking,dispersion and electrostatic adsorption are the main coagulation mechanisms of LiBH_(4)_FeOCl.The solid inorganic coagulant of LiBH4FeOCl provides a competitive alternative for traditional inorganic salts and organic coagulants.展开更多
For the first time,two-dimensional FeOCl(Fe_(1-x)Co_(x)OCl)doped with Co was successfully applied to the photocatalytic and photo-Fenton degradation of Rhodamine B(RhB).The photocatalytic and photo-Fenton experiments ...For the first time,two-dimensional FeOCl(Fe_(1-x)Co_(x)OCl)doped with Co was successfully applied to the photocatalytic and photo-Fenton degradation of Rhodamine B(RhB).The photocatalytic and photo-Fenton experiments showed that the degradation rates of RhB by Fe0.94Co0.06OCl are 82.6%and 98.2%within 50 min under neutral solution,room temperature and visible light.The inclusion of Co resulted in lattice imperfections on the surface of Fe OCl,which was advantageous for the photogenerated electron-hole pair separation efficiency(consistent with the density functional theory calculation).Moreover,the RhB removal rate decreased from 98%to 82%during five successive cycles,showing good structural stability.Finally,based on the radical capture experiment,a potential mechanism for RhB degradation by Fe_(1-x)Co_(x)OCl catalyst was proposed.The idea of a synergistic mechanism for Fe_(1-x)Co_(x)OCl also offers a fresh concept for catalysts used in doping modification.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.21622305 and21333003)the Young Elite Scientist Sponsorship Program by China Association for Science and Technology(No.YESS20150131)+1 种基金"Shu Guang"Project supported by Shanghai Municipal Education Commission and Shanghai Education Development Foundation(No.17SG30)the Fundamental Research Funds for the Central Universities(No.WJ1616007)
文摘Fe-based solid catalysts in promoting Fenton reaction to generate ·OH radical has drawn much attention,and interestingly,FeOCl was reported to have superior activity compared with the traditional Fe2 O3 catalysts.However,the mechanism of Fenton reaction on FeOCl and the origin of high activity remain unclear.Herein,by virtue of DFT+ U calculations,the H2 O2 decomposition and conversion mechanism on FeOCl(100)surface were systematically investigated.It is found that on clean FeOCl(100)surface,the exposed[Fe^3+-Fe^3+]sites can hardly break O-O bond of H2 O2 into OH groups,but instead H2 O2 tends to dehydrogenate by the surface lattice O,resulting in a series of side reactions and final conversion into O2,while the left H atoms gradually saturate the surface lattice O and reduce Fe^3+ into Fe^2+.On fully H-covered FeOCl(100),H2O2 can efficiently dissociate at[Fe^2+-Fe^2+]sites into two OH,but OH binds with Fe^2+ so strongly that it cannot desorb as OH radical as easily as that on Fe^3+.Interestingly,FeOCl(100)tends to be partially protonated in the real acid solution,which,along with H2 O2 dehydrogenation,results in the formation of active unit [Fe^2+-Fe^3+].On[Fe^2+-Fe^3+]unit,H2 O2 can easily break its O-O bond and OH at Fe3+ can desorb as OH radical,while the other OH at Fe^2+ couples with the surface H into H2O and finish the catalytic cycle.By comparison,Fe2 O3(012)cannot provide enough [Fe^2+-Fe^3+] active units due to the relative difficulty in H2 O2 dehydrogenation,which accounts for its inferior catalytic efficiency for Fenton reaction.
基金financial supports by the National Key Basic Research Program of China (No.2019YFC1906700)National Natural Science Foundation of China (Nos.21876049,51878643)University of Shanghai for Science and Technology (Grant Agreement No.ZR18PY01)。
文摘The textile industry spreads globally with the challenges of its wastewater treatment,especially dyes,which are difficult to degrade.To improve coagulation-flocculation process in dye wastewater treatment,an intercalation process was employed to prepare a new efficient coagulant of lithium borohydride-iron oxychloride(LiBH_(4)_FeOCl) in this study.The layered crystal pristine iron oxychloride(FeOCl) material was prepared by chemical gas phase migration.LiBH4 was introduced into the layers of two dimensional(2 D) FeOCl nanosheets by a simple method of liquid phase insertion.The samples were characterized by a field emitting scanning electron microscopy(SEM),a rotating anode X-ray powder diffractometer(XRD),etc.The cationic dye was employed as the simulated pollutant.A coagulation and decolorization experimental device was built to study the coagulation performance of the new coagulant LiBH_(4)_FeOCl.It is found that the intercalation modified LiBH_(4)_FeOCl exhibits the characteristics of crystal structure,and the layered structure of FeOCl is preserved.LiBH_(4)_FeOCl,as an insoluble inorganic solid coagulant,performs well for dye pollutants of methyl red,basic yellow 1,methylene blue,rhodamine B,ethyl violet and Janus green B.The reaction rate is significantly 68% higher than the current commercial coagulants of Al_(2)(SO_(4))_(3).The mechanism analysis reveals that LiBH_(4)_FeOCl breaks and disperses rapidly in the water environment.Its negatively charged material particles can be electrostatically adsorbed with dye pollutant molecules through electrostatic action.The above collaborative actions of breaking,dispersion and electrostatic adsorption are the main coagulation mechanisms of LiBH_(4)_FeOCl.The solid inorganic coagulant of LiBH4FeOCl provides a competitive alternative for traditional inorganic salts and organic coagulants.
基金the National Natural Science Foundation of China(Grant No.52268042)the Natural Science Foundation of Gansu Province+1 种基金China(Grant No.22JR5RA253)HongLiu First-Class Disciplines Development Program of Lanzhou University of Technology。
文摘For the first time,two-dimensional FeOCl(Fe_(1-x)Co_(x)OCl)doped with Co was successfully applied to the photocatalytic and photo-Fenton degradation of Rhodamine B(RhB).The photocatalytic and photo-Fenton experiments showed that the degradation rates of RhB by Fe0.94Co0.06OCl are 82.6%and 98.2%within 50 min under neutral solution,room temperature and visible light.The inclusion of Co resulted in lattice imperfections on the surface of Fe OCl,which was advantageous for the photogenerated electron-hole pair separation efficiency(consistent with the density functional theory calculation).Moreover,the RhB removal rate decreased from 98%to 82%during five successive cycles,showing good structural stability.Finally,based on the radical capture experiment,a potential mechanism for RhB degradation by Fe_(1-x)Co_(x)OCl catalyst was proposed.The idea of a synergistic mechanism for Fe_(1-x)Co_(x)OCl also offers a fresh concept for catalysts used in doping modification.
