CN113663730A - Iron-based organic framework composite material and preparation method and application thereof - Google Patents
Iron-based organic framework composite material and preparation method and application thereof Download PDFInfo
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Abstract
The invention discloses an iron-based organic framework composite material and a preparation method and application thereof. The preparation method comprises the following steps: g to C3N4、FeCl3·6H2O and H2Dissolving BDC in DMF to obtain a mixture, dispersing the mixture by ultrasonic wave, heating for reaction, cooling, and washingWashing, drying and grinding to obtain MIL-53(Fe)/g-C3N4Wherein g-C3N4、FeCl3·6H2O and H2The molar ratio of BDC is 3: 1: 1-4: 1: 1. the invention forms a heterojunction structure to promote conduction band transition electrons to carry out charge transfer between interfaces, thereby inhibiting the recombination of photogenerated electron-hole pairs, reducing the forbidden bandwidth of the material to widen the response range of visible light, carrying out visible light top irradiation in the degradation experimental process, and simultaneously adding an oxidant to have efficient oxidative degradation performance on dye wastewater.
Description
Technical Field
The invention relates to the technical field of sewage treatment, in particular to an iron-based organic framework composite material and a preparation method and application thereof.
Background
MIL-53(Fe) and g-C3N4All the photocatalysts can respond under visible light, have great photocatalytic application potential, meanwhile, the MIL-53(Fe) as an iron-based MOF can be used as a transition metal heterogeneous catalyst to activate peroxymonosulfate so as to generate active oxygen species to degrade organic pollutants, but still has the problems that the MIL-53(Fe) has a forbidden band width of about 2.5eV, and the photocatalytic degradation activity of the MIL-53(Fe) is influenced to a certain extent due to the narrow light absorption range of the MIL-53 (Fe); g-C3N4The material has good visible light response performance, but the recombination rate of photogenerated electrons and holes is high, and the photocatalysis performance is limited; the efficiency of degrading organic pollutants by the iron-based MOFs system still needs to be improved, and a mechanism capable of efficiently degrading high-concentration organic pollutants in a short time needs to be developed.
Disclosure of Invention
The invention aims to provide an iron-based organic framework composite material, a preparation method and application thereof, aiming at the defects in the prior art.
The preparation method of the iron-based organic framework composite material comprises the following steps:
g to C3N4、FeCl3·6H2O and H2BDC is dissolved in DMF to form a mixed solution, ultrasonic dispersion is used for the mixed solution, then the mixed solution is heated for reaction, cooled, washed, dried and ground to obtain the iron-based organic framework composite material MIL-53(Fe)/g-C3N4Which isMiddle g-C3N4、 FeCl3·6H2O and H2The molar ratio of BDC is 3: 1: 1-4: 1: 1.
further, said g-C3N4、FeCl3·6H2O and H2BDC molar ratio 3.4: 1: 1-3.7: 1: 1.
further, said g-C3N4、FeCl3·6H2O and H2BDC molar ratio is 3.5:1
Further, the heating reaction temperature is 150 ℃, the reaction time is 12h, and the reaction temperature is 5 ℃ min-1And (5) raising the temperature.
An iron-based organic framework composite material is prepared by the preparation method.
A method for treating dye wastewater, which is to use the iron-based organic framework composite material MIL-53(Fe)/g-C3N4Adding the solution into dye wastewater to reach adsorption-desorption equilibrium, adding peroxymonosulfate into the dye wastewater, and providing illumination conditions.
Further, when the dye concentration of the dye wastewater is 10-50mol/L, the MIL-53(Fe)/g-C3N4And the mass volume ratio of the peroxymonosulfate in the dye wastewater is 500-1000: 0.3074-0.6148.
Further, the pH value of the dye wastewater is 3-9.
Further, the pH value of the dye wastewater is 3-4.
The ultrasonic dispersion is uniform in the preparation process of the composite material, so that MIL-53(Fe) and g-C are mixed3N4Successful recombination, in this catalyst configuration, heterogeneously activated peroxymonosulfate was performed using iron-based MOFs-MIL-53 (Fe) instead of iron ions, and g-C3N4When the material is introduced into a heterogeneous system, electrons can be generated for redox conversion among Fe ions, and a heterojunction structure is formed to promote conduction band transition electrons to carry out charge transfer among interfaces, so that the recombination of photogenerated electron-hole pairs is inhibited, the forbidden bandwidth of the material is reduced to widen the response range of visible light, the recombination rate of the photogenerated electron and the hole is reduced, and the photocatalysis performance is improvedBetter, visible light top irradiation is carried out in the degradation experiment process, and meanwhile, the oxidant is added, so that the dye wastewater has efficient oxidative degradation performance.
Drawings
FIG. 1 MIL-53(Fe)/g-C3N4SEM picture of (1);
FIG. 2 MIL-53(Fe)/g-C3N4UV-Vis DRS Tauc Plot of the composite material;
FIG. 3 MIL-53(Fe), g-C3N4，MIL-53(Fe)/g-C3N4PL plot of composite material;
FIG. 4 MIL-53(Fe)/g-C3N4VBXPS plot of the composite;
FIG. 5a is a graph showing the effect of different systems on the removal of RhB;
FIG. 5b is a graph of the pseudo first order reaction kinetic rate constant k for different systems versus RhB;
FIG. 6 initial pH of the solution versus RhB removal (a) and pseudo first order reaction kinetic rate constant k (b);
FIG. 7 shows the effect of different material additions on the degradation of RhB (a) and the pseudo first-order reaction kinetic rate constant k (b);
FIG. 8 shows the degradation effect of catalytic materials with different composite proportions on RhB (a) and a pseudo first-order reaction kinetic rate constant k (b);
FIG. 9 is a graph of the UV-VIS diffuse reflectance spectra of various catalytic materials;
FIG. 10 Tauc plots for different catalytic materials;
FIG. 11 MIL-53(Fe)/g-C3N4A corresponding mechanism diagram in the reaction process of a system for degrading RhB by PMS/Vis;
FIG. 12 MIL-53(Fe)/g-C3N4VBXPS of the composite.
Detailed Description
The following are specific embodiments of the present invention and are further described with reference to the drawings, but the present invention is not limited to these embodiments.
Example 1
1.1 preparation
The iron-based organic framework composite material prepared by the implementation has good visible light responsiveness, a heterojunction structure and high separation efficiency of photo-generated electron-hole pairs, and the specific implementation steps are as follows:
3.00g of melamine was charged into a 50mL ceramic crucible, and heated in a muffle furnace at 550 ℃ for 3 hours (at 5 ℃ C. min)-1Heating), naturally cooling, taking out, and fully grinding with agate mortar to obtain g-C3N4. Prepared by a solvothermal method, and 1.5000g of FeCl is weighed3·6H2O and 0.9219g (with FeCl)3·6H2The ratio of the amounts of O substances is 1) H2BDC, and 0.1459g (FeCl)3·6H2The ratio of O to the amount of substance is 3.5) g-C3N4Dissolving in 30mL DMF, stirring for 30min, ultrasonic treating with ultrasonic cell disruptor for 60min, transferring into 100mL stainless steel reaction kettle with polytetrafluoroethylene lining, heating in muffle furnace at 150 deg.C for 12h (at 5 deg.C. min)-1Heating), naturally cooling to room temperature, centrifuging at 8000r min-1 for 5min to remove solvent, centrifuging and washing with anhydrous ethanol and ultrapure water for 3 times respectively, vacuum filtering with 0.22 μm microporous membrane, washing with ultrapure water and anhydrous ethanol for 2 times respectively, vacuum drying at 60 deg.C for 12 hr, grinding with agate mortar, and collecting MIL-53(Fe)/g-C3N4。
SEM picture shown in FIG. 1, MIL-53(Fe)/g-C prepared3N4The octahedral MIL-53(Fe) are uniformly and tightly distributed in the stacked g-C3N4The interlayer and the surface of the composite material are successfully prepared.
UV-Vis DRS (ultraviolet-visible diffuse reflectance Spectrum) Tauc Plut is shown in FIG. 2, and the prepared MIL-53(Fe)/g-C is obtained according to the formulas (1) and (2)3N4The band gap energy of the optical fiber is 2.18eV, the maximum absorption band edge is 568.81nm, the process of light-excited electronic transition is easier, the maximum absorption band edge is obviously red-shifted, and the visible light response range is enlarged.
(αhv)n＝A(hv-Eg) (1)
In the formula, when the material is a direct transition semiconductorN is 1/2, n is 2, α is the absorption coefficient, h is the planck constant, v is the frequency, EgIs forbidden band width, lambdamaxIs the maximum absorption band edge.
PL graph (photoluminescence spectrum) is shown in FIG. 3, MIL-53(Fe)/g-C3N4Is in a ratio of g-C to the photoluminescence intensity of3N4The obvious reduction indicates that the composite material ratio g-C3N4The recombination rate of the photo-generated electrons and the holes is lower, the separation of electron-hole pairs is promoted, the electron transfer efficiency is improved, and the redox reaction is favorably carried out.
VBXPS (X-ray photoelectron valence band spectrum) As shown in FIG. 4, the heterojunction formation of the composite material was verified, and the valence band potential (E) of the composite material was obtainedVB) 1.75eV at MIL-53(Fe) (2.10eV) and g-C3N4(1.58eV), it is inferred that a heterojunction is formed between the two. According to formula ECB＝EVB-EgCan further calculate MIL-53(Fe) and g-C3N4And MIL-53(Fe)/g-C3N4Conduction band potential (E)CB) Respectively-0.45 eV, -1.11eV, and-0.43 eV. And E of MIL-53(Fe)VBAnd ECBAre all higher than g-C3N4. Excited electrons transit from the valence band to the conduction band upon irradiation with visible light, g-C3N4The potential of the conduction band is lower, and the photogenerated electrons generated on the conduction band are transferred to the conduction band of MIL-53(Fe) through interface charges, so that the separation of the photogenerated electrons and holes is promoted, the recombination rate of electron holes is reduced, and the photocatalytic performance is effectively improved.
1.2 degradation Performance testing
MIL-53(Fe)/g-C prepared in this example 13N4The composite material shows the most excellent degradation performance to rhodamine B in a visible light coupling oxidant PMS system.
The experimental process specifically comprises the following steps:
0.05g of catalyst (variable: MIL-53(Fe) or g-C) was added at room temperature (20. + -. 2 ℃ C.), respectively3N4Or MIL-53(Fe)/g-C3N4) Adding 100mL of 50mg/L RhB solution (initial pH was not adjusted, about 4.15), and placing in the darkAfter 1h of medium adsorption to equilibrium, 1mM PMS solution (variable: present or absent) was added simultaneously and a visible light source (500W) was turned on for overhead illumination (variable: present or absent), the light source being 30cm in vertical height from the liquid surface. At defined time intervals ("-60" indicates a dark reaction), 2ml samples were taken and after rapid filtration through a 0.22 μm organic filter, the RhB concentration was determined by uv spectrophotometer at 554 nm. All experiments were repeated three times.
Figure 5 shows a control experiment comparing the removal of RhB by different systems. The removal kinetics curve of RhB conforms to the linear transformation ln (C)0The pseudo-first order process of kt, yields the pseudo-first order reaction kinetic rate constant k for the different systems (fig. 5 (b)). As shown in FIG. 4(a), g-C under dark conditions3N4、 MIL-53(Fe)、MIL-53(Fe)/g-C3N4(3.5) the three catalytic materials have certain adsorption effect on RhB. Target Material MIL-53(Fe)/g-C3N4Compared with MIL-53(Fe) and g-C3N4And the coupling with PMS, Vis and PMS/Vis thereof can improve the removal efficiency of RhB. MIL-53(Fe)/g-C under the coexistence condition of visible light and PMS3N4The catalytic effect of (2) was best, and 50mg/L RhB solution (fig. 5(b)) in system 12 (k: 0.07142 min) was removed in 50min-1) K values of (a) are respectively system 6(k is 0.01933 min)-1) And system 9 (k. 0.02023 min)-1) 2.98 times and 3.35 times of the reaction speed of the system of the invention is fastest.
1.3 pH application Range test
MIL-53(Fe)/g-C prepared in this example3N4Has wide pH application range.
The specific experimental steps are as follows: 0.05g of catalyst MIL-53(Fe)/g-C was added at room temperature (20. + -. 2 ℃ C.) separately3N4The composite material was added to 100mL of 50mg/L RhB solution (initial pH was not adjusted, about 4.15), and after equilibration by adsorption in the dark for 1h, 1mM PMS solution was added simultaneously and the visible light source (500W) overhead was turned on, the light source being 30cm in vertical height from the liquid surface. At defined time intervals ("-60" indicates a dark reaction), 2ml samples were taken and after rapid filtration through a 0.22 μm organic filter, the RhB concentration was determined by uv spectrophotometer at 554 nm. All experiments were repeated three times.
Changing the pH value of the RhB solution, repeating the experimental steps, and as shown in FIG. 6, the results show that when the pH value is 3-9, the removal rate of RhB reaches more than 99%, which indicates that MIL-53(Fe)/g-C3N4the/PMS/Vis system has a wide pH application range.
1.4 addition of Material to MIL-53(Fe)/g-C3N4Effect of/PMS/Vis on degradation of RhB
The specific experimental steps are as follows: 0.05g of catalyst MIL-53(Fe)/g-C was added at room temperature (20. + -. 2 ℃ C.) separately3N4The composite material was added to 100mL of 50mg/L RhB solution (initial pH was not adjusted, about 4.15), and after equilibration by adsorption in the dark for 1h, 1mM PMS solution was added simultaneously and the visible light source (500W) overhead was turned on, the light source being 30cm in vertical height from the liquid surface. At defined time intervals ("-60" indicates a dark reaction), 2ml samples were taken and after rapid filtration through a 0.22 μm organic filter, the RhB concentration was determined by uv spectrophotometer at 554 nm. All experiments were repeated three times.
Changing MIL-53(Fe)/g-C3N4The above experimental procedure was repeated with the amount of catalytic material added.
With MIL-53(Fe)/g-C3N4The addition of the catalytic material is increased, the degradation rate of RhB is continuously increased within the range of 0.1-1.0 g/L, and the final degradation rate is obviously improved.
As shown in FIG. 7, when the material addition was increased from 0.1g/L to 0.2g/L, the corresponding RhB removal rate was increased from 74% to 90%, and the reaction kinetic rate constant (k) was increased from 0.0262min-1Increased to 0.0431 min-1. However, when the amount of the catalyst was increased from 0.50g/L to 1.0g/L, the degradation rate was faster as the amount of the catalyst was increased, the time until the degradation rate reached 100% was changed from 50min to 30min, and the reaction kinetics rate constant (k) was changed from 0.0714min-1Increasing to 0.1094min-1The increase is 0.53 times. These information indicate that a moderate amount of photocatalyst is required to achieve excellent photocatalytic performance, that a higher amount of catalyst results in more active species being produced during the photocatalytic process, and that it is also possible that the initial R in solution is due to an increase in the amount of RhB adsorbed as a result of an increase in the amount of catalyst usedThe reduction in hB concentration accelerates the catalytic oxidation reaction in solution. At the same time, the catalyst dosage will increase the turbidity of the solution, possibly reducing the light transmittance through the RhB solution.
1.5 MIL-53(Fe)/g-C3N4Evaluation of the stability Properties of the catalytic Material
For MIL-53(Fe)/g-C prepared in example 13N4In the experimental process of three times of cyclic utilization of the catalytic material, MIL-53(Fe)/g-C3N4The catalytic material still shows good catalytic activity, and the degradation efficiency on RhB is 100%, 71.46% and 57.77% respectively.
Example 2
Composite molar ratio of material to MIL-53(Fe)/g-C3N4Effect of/PMS/Vis on degradation of RhB
Modification of FeCl in example 13·6H2O and g-C3N4The other operations were the same as in example 1.
The catalytic materials with different composite ratios have different removal effects on RhB, and MIL-53(Fe)/g-C with different composite ratios is shown in FIG. 83N4The removal effect on RhB is shown as: with g-C3N4The content increases, the removal rate of RhB shows a tendency of increasing first and then decreasing, MIL-53(Fe)/g-C3N4When the composite ratio x of the catalytic material is less than 3.5, the removal rate of RhB is increased and the degradation rate is obviously increased, which is caused by g-C3N4The introduction of the compound can red shift the absorption wavelength range of MIL-53(Fe), improve the response performance to visible light, and reduce g-C by forming a heterojunction between the two3N4Recombination of the photogenerated electrons and holes; with g-C3N4The content is increased, and the active sites on the surface of the composite material are gradually increased, so that the reaction rate of photocatalysis and PMS activation is accelerated, and the degradation effect of RhB is improved. The best results were achieved when the composite ratio x was 3.5, so MIL-53(Fe)/g-C was chosen in this study3N4(3.5) the material, RhB completely removed, the reaction rate reached the highest, its pseudo first order reaction kinetic rate constant k was 0.07142min-1Are each a composite ratioExample x is 4(k is 0.05084 min)-1) And x is 3(k is 0.05566 min)-1) 1.4 times and 1.28 times of the time. When the composite ratio x is greater than 3.5, g-C3N4Too large a relative content of (b) may affect the synthesis of the composite material and the reduction of the relative content of MIL-53(Fe), thereby reducing the degradation rate of RhB.
Example 3
MIL-53(Fe), g-C were tested in the 200-800nm wavelength range3N4And three composite proportions of MIL-53(Fe)/g-C3N4The light absorption values obtained by ultraviolet-visible light diffuse reflectance spectroscopy (UV-Vis DRS) are shown in fig. 9, and the advantages of the composite in terms of light absorption and band gap energy are analyzed. The Tauc diagram is drawn according to formula (3.1) where n is 1/2 for a material that is a direct transition semiconductor and 2 for an indirect transition semiconductor.
(αhv)n＝A(hv-Eg) Formula (3.1)
Thus, MIL-53(Fe) and MIL-53(Fe)/g-C3N4The n value of the composite material is selected from 1/2 g-C3N4Is n ═ 2, with (α hv)nThe vertical axis and hv are plotted on the horizontal axis, and as shown in fig. 10, the forbidden band width E of each material was calculatedgAnd maximum absorption band edge lambdamax(formula 3.2). MIL-53(Fe), g-C3N4、 MIL-53(Fe)/g-C3N4(3.5)、MIL-53(Fe)/g-C3N4(3)、MIL-53(Fe)/g-C3N4(4) E of (A)gThe values are respectively 2.55eV, 2.69eV, 2.18eV, 2.22eV and 2.19eV, and the maximum absorption band edge lambda is respectivelymax486.27nm, 460.97nm, 568.81nm, 558.56nm and 566.21nm respectively. As can be seen, MIL-53(Fe) was associated with g-C3N4The composite material has narrower forbidden band width than pure original material, can make the transition process of light excitation electron easier, and the maximum absorption band edge of the composite material is purer MIL-53(Fe) and pure g-C3N4All are obviously red-shifted, toThe response range performance of visible light is better. And 3.5 of the three ratios: 1 of the compositegMinimum value, maximum absorption band edge lambdamaxAt the maximum, the method possibly forms a heterojunction structure and thus has better visible light photocatalysis performance.
And (3) mechanism analysis:
MIL-53(Fe)/g-C3N4the corresponding mechanism in the reaction process of the system for degrading RhB by PMS/Vis is shown in figure 11:
MIL-53(Fe)/g-C3N4the catalyst generates electrons and holes (formula (1)) through visible light excitation, and the interface charge is from g-C3N4The conduction band transfer to the MIL-53(Fe) conduction band promotes efficient separation of electron holes. The reduction potential of the photo-generated electrons on the conduction band is-0.43 eV, which is lower than O2/
Standard redox potential of (-0.33eV vs NHE), thus e-Can be O2Capture generation
(formula (2)), which can react with photogenerated holes
And degrading RhB together. The oxidation potential of the hole on the valence band of the composite material is 1.75eV which is less than OH−/
Standard redox potential of (2.40eV vsNHE), MIL-53(Fe)/g-C3N4The hole in (2) can not be substituted with OH−Or H2O is directly oxidized to obtain
But O2Can be generated by multiple electron transfer pathways
That is to sayThat is, the photo-generated electrons can be transferred to ubiquitous oxygen molecules, first forming
Then is protonated to form
The free radical (formula (3)), which is then HOO ∙ and the trapped electron combine to form H2O2(formula (4)), finally forming
Radical (formula (5)). In addition, photo-generated electrons react with PMS to form
(formulae (6) to (9)), in part
May be further reacted with H2Formation of O by reaction
A free radical.
Can be reacted with H2Formation of O by reaction1 
And also has a certain oxidizing ability (formula (10)). The above experiment confirmed that MIL-53(Fe)/g-C3N4The visible light catalytic oxidation and the activated PMS have synergistic effect,
1 
are the main free radicals which can co-oxidize the contaminants to give non-toxic or low-toxicDegradation products (formula (11))
The heterojunction formation of the composite material was verified:
MIL-53(Fe)/g-C was tested3N4VBXPS of the composite, as shown in FIG. 12, gives the valence band potential E of the compositeVB1.75eV, E of MIL-53(Fe) according to the prior studyVBIs 2.10eV, g-C3N4E of (A)VBThe valence band potential of the composite material is 1.58eV, so that it can be inferred that a heterojunction is formed between the two. Band gap energy E calculated from the previousgThe conduction band potential E can be further calculatedCB=EVB-EgThus, E of MIL-53(Fe)CBIs-0.45 eV, g-C3N4E of (A)CBIs-1.11 eV, MIL-53(Fe)/g-C3N4E of composite materialsCBIs-0.43 eV. E of MIL-53(Fe) in the composite MaterialCBHigher than g-C3N4E of MIL-53(Fe)VBHigher than g-C3N4When visible light irradiates an excited state of an electron, the electron transits from the valence band to the conduction band, g-C3N4The potential of the conduction band is lower, and the photogenerated electrons generated on the conduction band are transferred to the conduction band of MIL-53(Fe) through interface charges, so that the separation of the photogenerated electrons and holes is promoted, the recombination rate of electron holes is reduced, and the photocatalytic oxidation performance is effectively improved.
The heterojunction formation of the composite material was verified:
MIL-53(Fe)/g-C was tested3N4VBXPS of the composite, as shown in FIG. 12, gives the valence band potential E of the compositeVB1.75eV, E of MIL-53(Fe) according to the prior studyVBIs 2.10eV, g-C3N4E of (A)VBThe valence band potential of the composite material is 1.58eV, so that it can be inferred that a heterojunction is formed between the two. Band gap energy E calculated from the previousgThe conduction band potential E can be further calculatedCB＝EVB-EgTherefore, MIL-E of 53(Fe)CBIs-0.45 eV, g-C3N4E of (A)CBIs-1.11 eV, MIL-53(Fe)/g-C3N4E of composite materialsCBIs-0.43 eV. E of MIL-53(Fe) in the composite MaterialCBHigher than g-C3N4E of MIL-53(Fe)VBHigher than g-C3N4When visible light irradiates an excited state of an electron, the electron transits from the valence band to the conduction band, g-C3N4The potential of the conduction band is lower, and the photogenerated electrons generated on the conduction band are transferred to the conduction band of MIL-53(Fe) through interface charges, so that the separation of the photogenerated electrons and holes is promoted, the recombination rate of electron holes is reduced, and the photocatalytic oxidation performance is effectively improved.
The above is not relevant and is applicable to the prior art.
While certain specific embodiments of the present invention have been described in detail by way of illustration, it will be understood by those skilled in the art that the foregoing is illustrative only and is not limiting of the scope of the invention, as various modifications or additions may be made to the specific embodiments described and substituted in a similar manner by those skilled in the art without departing from the scope of the invention as defined in the appending claims. It should be understood by those skilled in the art that any modifications, equivalents, improvements and the like made to the above embodiments in accordance with the technical spirit of the present invention are included in the scope of the present invention.
Claims (9)
1. A preparation method of an iron-based organic framework composite material is characterized by comprising the following steps: the method comprises the following steps: g to C3N4、FeCl3·6H2O and H2BDC is dissolved in DMF to form a mixed solution, ultrasonic dispersion is used for the mixed solution, then the mixed solution is heated for reaction, cooled, washed, dried and ground to obtain the iron-based organic framework composite material MIL-53(Fe)/g-C3N4Wherein g-C3N4、FeCl3·6H2O and H2The molar ratio of BDC is 3: 1: 1-4: 1: 1.
2. the method of preparing an iron-based organic framework composite material according to claim 1, wherein: the g to C3N4、FeCl3·6H2O and H2BDC molar ratio 3.4: 1: 1-3.7: 1: 1.
3. a method of making an iron-based organic framework composite material as claimed in claim 2, wherein: the g to C3N4、FeCl3·6H2O and H2BDC molar ratio is 3.5:1
4. The method of preparing an iron-based organic framework composite material according to claim 1, wherein: the heating reaction temperature is 150 ℃, the reaction time is 12h, and the reaction temperature is 5 ℃ min-1And (5) raising the temperature.
5. An iron-based organic framework composite material, which is characterized in that: prepared by the preparation method as described in any one of claims 1 to 4.
6. A method for treating dye wastewater is characterized by comprising the following steps: mixing the iron-based organic framework composite material MIL-53(Fe)/g-C of claim 53N4Adding the solution into dye wastewater to reach adsorption-desorption equilibrium, adding peroxymonosulfate into the dye wastewater, and providing illumination conditions.
7. The method for treating dye wastewater according to claim 6, wherein: when the dye concentration of the dye wastewater is 10-50mol/L, the MIL-53(Fe)/g-C3N4And the mass volume ratio of the peroxymonosulfate in the dye wastewater is 500-1000: 0.3074-0.6148.
8. The method for treating dye wastewater according to claim 6, wherein: the pH value of the dye wastewater is 3-9.
9. The method for treating dye wastewater according to claim 8, wherein: the pH value of the dye wastewater is 3-4.
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