CN112827497B

CN112827497B - Preparation method of ozone catalytic material

Info

Publication number: CN112827497B
Application number: CN202011641742.4A
Authority: CN
Inventors: 肖艳春; 郭绍英; 陈彪; 黄婧; 陈芳; 刘瑞来
Original assignee: Institute of Agricultural Engineering Technology of Fujian Academy of Agricultural Sciences; Fujian Polytechnic Normal University
Current assignee: Institute of Agricultural Engineering Technology of Fujian Academy of Agricultural Sciences; Fujian Polytechnic Normal University
Priority date: 2020-12-31
Filing date: 2020-12-31
Publication date: 2022-07-08
Anticipated expiration: 2040-12-31
Also published as: CN112827497A

Abstract

The invention provides a preparation method of an ozone catalytic material, which comprises the following steps: soaking clean alumina in a cobalt chloride solution, adding a sodium hydroxide solution to adjust the pH value to 8-9, performing ultrasonic treatment in a water bath, drying and calcining to obtain modified alumina; dissolving metal nitrate and citric acid in deionized water to obtain a precursor solution, adding the modified alumina into the precursor solution, performing water bath ultrasound, drying, and calcining by adopting a stepped gradient heating method to obtain a solid material; and (3) soaking the solid material in an ammonium nitrate aqueous solution, carrying out water bath ultrasonic treatment for 0.5h, filtering, washing, drying and calcining to obtain the ozone catalytic material. The invention has the beneficial effects that: the introduction of manganese, cobalt and cerium metal oxides and the gradient heating calcination method increase the active sites of the material and improve the dispersibility of active substances; the hydroxylation modification improves the hydrophilicity and is beneficial to O₃And tetracycline TC is adsorbed on the surface of the material, so that the para-O is enhanced₃The decomposition rate of the catalyst greatly improves the TC mineralization rate.

Description

Preparation method of ozone catalytic material

Technical Field

The invention relates to a preparation method of an ozone catalytic material, belonging to the technical field of sewage treatment.

Background

Tetracycline (TC) is one of the most widely used antibiotics in the world, and is often used as a livestock growth promoter added into livestock breeding feed due to the advantages of broad spectrum, high quality, low price and the like. However, TC is difficult to be completely absorbed and utilized by animals, and about 30% to 90% of TC can enter water and soil in the form of parent compounds through various routes such as surface runoff and leaching. It has been reported that TC residues have been detected in surface water, ground water, municipal sewage, and soil in the order of ng.L^-1To mg.L^-1Are not equal. It has been shown that a great deal of dangerous TC is degraded in the natural environment to form primary degradation products with toxicity equal to or higher than that of the parent compound, and may enter human body through food chain to cause adverse reactions, such as poisoning, carcinogenesis, etc. It is also possible to induce the development of resistant microorganisms and resistance genes, even "super-resistant bacteria", with the expectation that 1 million will die globally from resistant infections each year by 2050. Therefore, the development of an environmentally-friendly and efficient TC mineralization method has important scientific significance and wide application prospect for ecological environment protection and human health protection.

TC chemical formula C₂₂H₂₄N₂O₈Molecular weight of 444.4 g/mol^-1An amphiphilic molecule having multiple ionizable functional groups; the parent nucleus is a hydrogenated tetracene skeleton unit with antibacterial activity; the substituent on C1-C4 is a basic pharmacophore; the diketone structures on C1 and C11 have important effects on antibacterial activity, and the molecular structures are shown in fig. 1. At present, a plurality of scholars at home and abroad carry out extensive research on the removal of TC in a water body. The removal method mainly comprises a biological method, an adsorption method, an oxidation method and the like, and the methods have some defects, such as: (1) the biological method is a conventional method for treating organic pollutants and comprises an anaerobic activated sludge method, an aerobic sludge method, anaerobic and aerobic combined treatment and the like. But do notThe biological treatment method has a long treatment period, and meanwhile, because TC is difficult to be completely oxidized and degraded due to the degradation-resistant characteristic, and microorganisms in the sludge can inhibit the TC, the TC is easy to be prevented from being treated and remain in a terminal water body due to the comprehensive effect of the two factors. (2) Electron-donating groups such as carbonyl, amino and the like on the TC molecular structure enable the TC molecular structure to be easily coordinated with metal ions; meanwhile, the higher hydrophobicity of TC and the planar structure of the tetracene molecules can enhance the van der Waals acting force between the TC and the adsorbent. The combined action of the two aspects is beneficial to the generation of adsorption. Li et al (LiR, Zhang Y, Dengh, et al. moving tetracycline and Hg (II) with ball-milli-imaging nanobiochar and iterative amplification water reaction [ J]Journal of Hazardous materials,2020,384: 121095) adsorbed TC by wheat straw ball-milled magnetic nano biochar (BMBCs) with a removal rate of not less than 99%. Kim et al (Kim EJ, Bhatia KS, SongJH, et al, adsorbed removal of an infectious agent by a major leaf-derived biochar [ J]Bioresource Technology,2020,306:123092.) in combination with FTIR and XPS analysis demonstrated that TC removal is primarily mediated by electrostatic, hydrogen bonding, and C π -C π interactions. Also scholars (Xiong W, Chen N, Feng CP, et al. organic catalysis carbon for the treatment of the molecular of phenol [ J].Environmental Science andPollution Research,2019,26:21022-21033.LiuHJ,Yang Y,KangJ,et al.Removal oftetracyclinefrom water byFe-Mn binary oxide[J]Journal of environmental sciences,2012,24(2):242-247.) a binary oxide formed by compounding manganese and other metal oxides is used as an adsorbent to remove TC, and it is consistent that the adsorption mechanism is mainly that surface hydroxyl groups on the oxides are replaced by TC species, and a surface complexation reaction occurs at a water/oxide interface to realize efficient removal of TC. The adsorption method based on the physical principle only realizes the transfer of the pollutants, so that TC is transferred to the surface of the adsorbent and the interior of the adsorbent, and the pollutants are not really removed from the water body. (3) The advanced oxidation technologies (AOPs) have high removal rate for persistent organic matters difficult to biodegrade by virtue of high reactivity of hydroxyl radicals (. OH), and mainly comprise photocatalytic oxidation, Fenton oxidation, ozone oxidation and the like. Mboula et al (Mboula VM, H quest V, Gru Y, et alsment ofthe efficiency ofphotocatalysis on tetracycline biodegradation[J]Journal of Materials,2012,209-210:355-364.) studies show that the by-product structure generated during the photodegradation of TC is similar to that of the parent, and the parent ring is not completely opened and still has great ecotoxicity. Ma et al (Ma S, JingJ, Liu P, et al. high selection sensitivity and sensitivity for removing the information about cycle and its related drug resistance in the information about water heater through the schwertmannite/the phenol oxide captured photo-Fenton-like oxidation [ J S, Jing J, Liu P]Journal of materials 2020,392: 122437) a novel schwertmannite/graphene oxide (SCH/GO) nanocomposite was synthesized by oxidation-co-precipitation method to catalyze H₂O₂The resultant product undergoes Fenton-like oxidation with TC under visible light, and although TC is completely removed, the degradation rate (mineralization rate) of Total Organic Carbon (TOC) is only 27.3%. Khan et al (Khan MH, BaeH, JungJY. Tetracycle degradation by catalysis in the aqueous phase: pro-segregation intermediates and dpathway [ J]Journal of Hazardous materials,2010,181(1-3):659-665.) study the process of ozonation of TC in water at pH 2.2 and 7.0, elucidating the C11a-C12 and C2-C3 double bonds, dimethylamino groups on C4, and benzene rings between C6a and C10 in the TC structure from functional group protonation, dissociation and radical angle, as shown in FIG. 1, all of the electron-rich groups are the attack sites of ozone and radical ozonation products, and although TC is completely removed, the mineralization rate is only 40%. Dalm-zio et al (Dalm zioI, Almeida MO, AugustR, et al. monitoring the degradation of tetracycline by ozone in aqueous medium of adsorption method [ J]Journal of American society for Mass Spectrometry,2007,18(4): 679-. Most of the researches are carried out on the aspect of removing TC, the antibacterial activity change of TC parent bodies is not concerned, the mineralization rate is generally low, and the ecological risk is extremely high. Therefore, how to improve the TC mineralization rate is very interesting and studied.

For emerging micropollutants, such as pesticides, pharmaceuticals, etc., it is difficult to directly mineralize using ozone alone. Heterogeneous phaseCatalytic ozonation provides a unique solution for efficient degradation (mineralization) of persistent micropollutants. Compared with single ozone oxidation, the mineralization rate is greatly improved even if a low-concentration catalyst is used. Afzal et al (Afzal S, QuanX, Sen L. catalysis and analysis of the mechanical inside of CeO₂nanocrystals with different characterization Methods[J]Applied catalysis B Environmental 2019,248:526-₂Catalyzing ozone to oxidize phenolic wastewater, wherein the mineralization rate reaches 86 percent. Liu et al (Liu YF, ZhaoJN, LiZX, et al, catalytic oxidation of bisphenola in aqueous solution using Mn-Ce/HZSM-5as catalyst [ J].WaterScience&Technology,2015,72(5): 696-. Xing et al (Xings T, LuXY, LiuJ, et al, catalytic catalysis of sulfonic acid overexpression uptake oxidant uptake of mesoporous bacteria, river [ J]Chemosphere,2016,144:7-12.) preparation of MnO Supported on mesoporous Ce_xAnd is used for catalyzing ozone to oxidize sulfosalicylic acid, and the mineralization rate reaches 95 percent. The catalytic ozonation mechanism combined with the above studies led to the following conclusions: ce³⁺/Ce⁴⁺Is a redox reaction and an active oxygen species (ROSs, singlet atomic oxygen (1O)₂) Superoxide (O)₂ ^-) Peroxidized species (. O)₂ ^2-) And. OH) plays an important role in catalyzing the ozone oxidation of micropollutants; oxide thereof (CeO)₂) And MnO with MnO_xAfter compounding, Lewis acid sites are increased, so that the catalytic ozone oxidation efficiency is further improved. However, the catalytic ozonation process does not form a uniform mechanism, one of which considers that the mineralization of target pollutants depends on the redox cycling of metal ions by electron transfer. The specific process is as follows: transfer of electrons to O by metal ions in the Lewis acid site₃Decomposition to 1O₂Or O₂ ^-And further with another O₃Reaction to produce O₂ ^2-，·O₂ ^2-Electrons are also given to metal ions on Lewis acid sites to realize redox circulation during whichTo these active oxygen species (1O)₂And O₂ ^-) Attack the organic contaminants adsorbed on the catalyst surface (including target contaminants and organic intermediates) and eventually achieve a high degree of mineralization. Another mechanism considers that mineralization of target pollutants is dependent on O₃Metal Lewis acid sites, surface hydroxyl and surface complexation of organic intermediates. The specific process is as follows: the target pollutant is not easy to be adsorbed on the surface of the catalyst, and is adsorbed on the surface hydroxyl position₃Molecular decomposition to form OH, OH and O₃Diffusing and attacking target pollutant in the bulk solution to quickly generate an organic intermediate, wherein the organic intermediate is adsorbed on a metal Lewis acid site through surface complexation and is further adsorbed by O of a nearby surface hydroxyl site₃And OH attack to achieve high mineralization. Both mechanisms irrefutably indicate that surface hydroxyl groups and Lewis acid sites have a large impact on the behavior of ozone and contaminants on the catalyst surface. Therefore, the generation of ROS species and the adsorption behavior of contaminants on the catalyst surface by both are still under further investigation.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a preparation method of an ozone catalytic material.

A preparation method of an ozone catalytic material comprises the following steps:

soaking clean alumina in 0.15 g/mL^-1Adding 3M sodium hydroxide solution into the cobalt chloride solution to adjust the pH value to 8-9, carrying out water bath ultrasonic treatment at 70-80 ℃ for 0.5h, drying at 120 ℃ for 3h, and calcining at 400-500 ℃ in an air atmosphere for 1-3 h to obtain modified alumina;

dissolving metal nitrate and citric acid in deionized water to obtain a precursor solution, adding the modified alumina into the precursor solution, performing water bath ultrasound, drying, and calcining by adopting a stepped gradient heating method to obtain a solid material;

immersing the solid material in an ammonium nitrate aqueous solution, carrying out water bath ultrasonic treatment for 0.5h, filtering, washing, drying in vacuum at 100-200 ℃ for 3-5 h, and then carrying out N at 400-600 DEG C₂Calcining for 2-4 h in atmosphere to obtain the ozone catalytic materialAnd (5) feeding.

Preferably, the volume ratio of the clean alumina to the cobalt chloride solution is 1: 1.

Preferably, the preparation method of the clean alumina comprises the following steps: alpha-Al is added₂O₃The mixture is soaked in 1M hydrochloric acid and then 1M sodium hydroxide for 5 hours respectively, and then is washed to be neutral by deionized water.

Preferably, the metal nitrate is manganese nitrate or a mixture of manganese nitrate and cerium nitrate, and the molar ratio of manganese to cerium in the mixture of manganese nitrate and cerium nitrate is 7:3, 1:1 or 3: 7.

As a preferred scheme, the step gradient heating method specifically comprises the following steps: heating from room temperature to 200 ℃ at the speed of 10 ℃/min, and keeping the temperature for 2 h; and stage II: heating from 200 ℃ to 400 ℃ at the speed of 5 ℃/min, and preserving heat for 3 h; stage III: cooling from 400 deg.C to 200 deg.C at 3 deg.C/min, and naturally cooling to room temperature.

Preferably, the mass fraction of the ammonium nitrate aqueous solution is 10%.

Preferably, the mass ratio of the solid material to the aqueous ammonium nitrate solution is 1: 3.

An ozone catalytic material obtained by the preparation method.

Compared with the prior art, the invention has the following beneficial effects:

1. ce, Mn and Co are introduced into SA, and an ozone catalytic material prepared by a stepped gradient heating calcination method and hydroxylation modification is adopted, so that active components which are not completely activated are further activated in the calcination process, the active sites of the material are increased, and the dispersibility of active substances is improved;

2. the ammonium nitrate impregnation increases the number of surface hydroxyl groups, increases the hydrophilicity of the catalytic material and is beneficial to O₃And TC adsorbs on the surface of the catalytic material to accelerate O₃The rate of oxidation of TC to an organic intermediate.

3. Co of Lewis acid site has excellent electron transfer efficiency, plays a role in electron shuttling in the reaction process, and activates O in cooperation with cerium and manganese₃Rapidly decomposed into OH and O₂ ^-Adsorption ofFurther conversion of organic intermediates on microsphere surfaces to CO₂And H₂And O, achieving a high mineralization effect.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

FIG. 1 is a schematic diagram of the TC molecular structure and ozone attack site;

FIG. 2 is a schematic diagram of a process unit for catalytic ozonolysis of TC;

FIG. 3 is a graph of reaction time versus TOC removal;

FIG. 4 is SEM electron micrographs of the ozone catalytic material of example 3 before and after use;

FIG. 5 is a 3DEEM spectrogram of medical biochemical wastewater before and after treatment with the ozone catalytic material of the present invention.

In the figure: 1. an ozone generator; 2. a TC liquid tank; 3. an ozone concentration analyzer; 4. a peristaltic pump; 5. an ozone reaction column; 6. an ozone destructor; 7. a liquid storage tank; 8. a multi-well plate.

FIG. 6 microspheres/O of example 1₃For COD and NH in high-salinity biochemical wastewater₄ ⁺-cyclic removal effect of N.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.

Example 1

The embodiment provides a preparation method of an ozone catalytic material, which specifically comprises the following steps:

(1) while continuously stirring, 3M sodium hydroxide solution was added dropwise to 0.15 g/mL^-1The pH value of the cobalt chloride solution soaked with clean alumina (SA) is adjusted to 8-9, the cobalt chloride solution is subjected to ultrasonic treatment in water bath at 70-80 ℃ for 0.5h (the soaking process is repeated), and the cobalt chloride solution is firstly placed inDrying in a 120 ℃ oven for 3h, and calcining in a muffle furnace at 450 ℃ in air atmosphere for 2h to obtain modified alumina, which is recorded as mSA for later use;

(2) adding 3M manganese nitrate Mn (NO)₃)₂·4H₂O and 7M cerium nitrate Ce (NO)₃)₃·6H₂Dissolving O and 1M citric acid in deionized water to prepare a precursor solution, stirring vigorously for 1h, immersing mSA obtained in the step (1) in the precursor solution, carrying out water bath ultrasonic treatment for 0.5h (the immersion process is repeated), drying at 120 ℃ for 3h, placing in a muffle furnace, and calcining by a step gradient heating method (stage I, heating from room temperature to 200 ℃ at 10 ℃/min, keeping the temperature for 2h, stage II, heating from 200 ℃ to 400 ℃ at 5 ℃/min, keeping the temperature for 3h, stage III, cooling from 400 ℃ to 200 ℃ at 3 ℃/min, and naturally cooling to room temperature) to obtain the solid material.

(3) Soaking the solid material obtained in step (2) in 10 wt% ammonium nitrate solution (hydroxylation reagent) at a solid-to-liquid ratio of 1:3, performing ultrasonic treatment in water bath for 0.5h, filtering, washing, drying in a vacuum drying oven at 150 deg.C for 4h, and then drying in a N atmosphere at 500 deg.C₂Calcining for 3 hours in a muffle furnace under the atmosphere to obtain an ozone catalytic material, which is marked as 3MnO₂-7CeO₂@mSA。

Example 2

(1) while continuously stirring, 3M sodium hydroxide solution was added dropwise to 0.15 g/mL^-1The method comprises the following steps of (1) adjusting the pH value to 8-9 in a cobalt chloride solution soaked with clean alumina (SA), carrying out water bath ultrasonic treatment for 0.5h at 70-80 ℃ (the soaking process is repeated), firstly placing the cobalt chloride solution in a 120 ℃ drying oven for drying for 3h, and then placing the cobalt chloride solution in a 450 ℃ muffle furnace in an air atmosphere for calcining for 2h to obtain modified alumina, wherein the modified alumina is recorded as mSA for later use;

(2) adding 5M manganese nitrate Mn (NO)₃)₂·4H₂O and 5M cerium nitrate Ce (NO)₃)₃·6H₂Dissolving O and 1M citric acid in deionized water to prepare a precursor solution, stirring vigorously for 1h, soaking mSA obtained in step (1) in the precursor solution, performing ultrasonic treatment in water bath for 0.5h (the soaking process is repeated), drying at 120 deg.C for 3h, and placing in a muffle furnace by using a step ladderCalcining by temperature rising method (stage I, heating from room temperature to 200 deg.C at 10 deg.C/min, holding for 2 hr, stage II, heating from 200 deg.C to 400 deg.C at 5 deg.C/min, holding for 3 hr, and stage III, cooling from 400 deg.C to 200 deg.C at 3 deg.C/min, and naturally cooling to room temperature) to obtain solid material.

(3) Soaking the solid material obtained in step (2) in 10 wt% ammonium nitrate solution at a solid-to-liquid ratio of 1:3, performing ultrasonic treatment in water bath for 0.5h, filtering, washing, drying in a vacuum drying oven at 150 deg.C for 4h, and drying in N at 500 deg.C₂Calcining for 3 hours in a muffle furnace under the atmosphere to obtain an ozone catalytic material, which is marked as 5MnO₂-5CeO₂@mSA。

Example 3

(1) while continuously stirring, 3M sodium hydroxide solution was added dropwise to 0.15 g/mL^-1The method comprises the following steps of (1) adjusting the pH value to 8-9 in a cobalt chloride solution soaked with clean alumina (SA), carrying out water bath ultrasonic treatment for 0.5h at 70-80 ℃ (the soaking process is repeated), firstly placing the cobalt chloride solution in a drying oven at 120 ℃ for drying for 3h, and then placing the cobalt chloride solution in an air atmosphere at 450 ℃ for calcining in a muffle furnace for 2h to obtain modified alumina, wherein the modified alumina is recorded as mSA for later use;

(2) adding 7M manganese nitrate Mn (NO)₃)₂·4H₂O and 3M cerium nitrate Ce (NO)₃)₃·6H₂Dissolving O and 1M citric acid in deionized water to prepare a precursor solution, stirring vigorously for 1h, immersing mSA obtained in the step (1) in the precursor solution, carrying out water bath ultrasonic treatment for 0.5h (the immersion process is repeated), drying at 120 ℃ for 3h, placing in a muffle furnace, and calcining by a step gradient heating method (stage I, heating from room temperature to 200 ℃ at 10 ℃/min, keeping the temperature for 2h, stage II, heating from 200 ℃ to 400 ℃ at 5 ℃/min, keeping the temperature for 3h, stage III, cooling from 400 ℃ to 200 ℃ at 3 ℃/min, and naturally cooling to room temperature) to obtain the solid material.

(3) Soaking the solid material obtained in step (2) in 10 wt% ammonium nitrate solution (hydroxylation reagent) according to a solid-to-liquid ratio of 1:3, performing ultrasonic treatment in water bath for 0.5h, filtering, washing, drying in a vacuum drying oven at 150 ℃ for 4h, and then drying in an N atmosphere at 500 ℃₂Calcining the mixture for 3 hours in a muffle furnace under the atmosphere to obtain the ozone catalytic materialAnd is denoted as 7MnO₂-3CeO₂@mSA。

Comparative example 1

This comparative example provides a method for preparing an ozone catalytic material, differing from example 1 only in that 5M manganese nitrate Mn (NO) was used only in step 2₃)₂·4H₂Dissolving O and 1M citric acid in deionized water to prepare a precursor solution.

Comparative example 2

This comparative example provides a method for preparing an ozone catalytic material, differing from example 1 only in that only 5M cerium Ce Nitrate (NO) was used in step 2₃)₃·6H₂Dissolving O and 1M citric acid in deionized water to prepare a precursor solution.

TC is a water-soluble pollutant, and in order to evaluate the catalytic performance of the above 5 ozone catalytic materials, the above comparative examples and examples were used in the process of catalytic oxidation of TC by ozone. The structure of the catalytic reaction device is shown in fig. 3: ozone generator 1 and TC liquid tank 2 communicate with the bottom of ozone reaction column 5 through the pipeline respectively, be equipped with ozone concentration analysis appearance 3 between ozone generator 1 and the ozone reaction column 5, be equipped with peristaltic pump 4 between TC liquid tank 2 and the ozone reaction column 5, ozone destructor 6 communicates in the top of ozone reaction column 5, be provided with a plurality of perforated plates 8 in the ozone destruction column 5, be used for placing catalytic material, the upper portion of liquid storage tank 7 and ozone reaction column 5 is linked together, be used for receiving the sewage after ozone catalytic treatment.

The specific method comprises the following steps:

step a: uniformly adding a catalytic material into an ozone reaction column (made of organic glass) in three layers (by adopting a wet sample adding method, soaking the ozone reaction column with deionized water for 12 hours before use, and then draining the mixture), wherein the filling rate is 25%;

step b: mixing 100 mg.L^-1Introducing an ozone reaction column into the TC solution through a peristaltic pump, then starting an ozone generator and introducing O₃，O₃The concentration is 30 mg.L^-1And sampling and detecting after reacting for a certain time.

Step c: the repeated performance evaluation was performed under the optimal process conditions.

Table 1 surface acidity and treatment effect on TC of catalytic materials of comparative and example each

As can be seen from Table 1, the TC removal rate and the mineralization rate are in positive correlation with the surface acidity of the catalyst, wherein in example 3, that is, when the molar ratio of Mn to Ce is 7:3, the surface acidity is the highest (2.85 mmol. multidot.g)^-1) O is₃After reacting for 60min, the corresponding TC mineralization rate is also the highest (90.84%). Taking the catalytic material prepared in example 3 as an example, the degradation effects of the three processes of ozone oxidation, catalytic ozonation and catalytic ozonation circulating 12 times on TC were further compared, and the results are shown in fig. 3. As can be seen from fig. 3, the degradation efficiency of the TC by the three processes is significantly different, wherein the ozone oxidation degradation efficiency is low, when the reaction apparatus runs for 60min, the TOC removal rate is only 53.7%, while the catalytic ozonation can reach 90.0%, the cycle time can still reach 83%, and the removal rate of the TOC of the TC wastewater by the adsorption of the catalytic material is only extremely small, i.e., 7.2%, which indicates that the catalytic ozonation reaction process contributes most to the TC mineralization rate in the wastewater degradation process, and the catalytic material of example 3 plays a significant role in the ozonation reaction. As can be seen in FIGS. 4a (before use) and 4b (after use), 7MnO was 12 times recycled₂-3CeO₂The manganese-cerium composite oxide loaded on the surface of @ mSA has no obvious change, which indicates that the ozone catalytic material has better stability.

As can be seen from fig. 3, the presence of t-butanol and benzoquinone significantly reduced TC mineralization rates, with the two radical scavengers having different radical scavenging capabilities. The addition of excessive OH trapping agent tert-butyl alcohol (10mM) has great interference effect on the removal efficiency of the catalytic reaction, and the mineralization efficiency of the reaction system to TC is lower than that of single O₃Oxidation, which indicates that OH exists in the reaction system and plays a leading role; but at the same time, it is also seen that O is added₂ ^-After the trapping agent benzoquinone (10mM), the mineralization efficiency of the reaction system to TC is higher than that of the reaction system to TC alone₃Oxidation, which verifies the co-presence of O in the reaction system₂ ^-And indirect oxidation of OH and O₃The contribution rate of the direct oxidation of the molecules is OH>O₃>·O₂ ^-。

Application test:

in order to further examine the effect of the ozone catalytic material prepared in example 3 on the application of actual wastewater. An experiment was carried out with MBR effluent of certain solid waste disposal Co., Ltd. (perennial incineration of medical waste) of Fujian province as a research object, and the wastewater quality index is shown in Table 2. As can be seen from Table 2, COD and NH₄ ⁺The N value is far higher than the water quality of industrial water for recycling municipal sewage (GB/T19923-2005) and the water supplement standard of an open type circulating cooling water system in the table 1.

TABLE 2 basic physicochemical properties of medical biochemical wastewater

Fig. 5 shows three-dimensional fluorescence spectra before and after the wastewater treatment (fig. 5a and fig. 5b show before and after the treatment, respectively), and the wastewater mainly contains 1 clear fluorescence peak before the treatment (fig. 5a), and the visible fulvic acid can be determined as a hardly degradable organic substance according to the fluorescence peak position Ex/Em of 340nm/420 nm. After 30min ozone catalytic oxidation treatment, the fluorescence peak disappeared (fig. 5b), and the specific index parameter changes as follows: COD is 629 mg.L^-1Reduced to 53.8 mg.L^-1，NH₄ ⁺-N is comprised of 58.9 mg.L^-1Reduced to 3.7 mg.L^-1TOC of 253.4 mg.L^-1Reduced to 38.3 mg.L^-1，Cl^-From 4427.0 mg. L^-1Reduced to 1237.2 mg.L^-1The removal rates are 91.4%, 93.7%, 84.9% and 72.1%, respectively. The humic substance level is gradually reduced due to low molecular weight or mineralization of the fulvic acid-like humic substance, and the persistent organic substances remained in the medical biochemical wastewater are obviously removed. Therefore, the ozone catalytic material prepared by the invention has remarkable catalytic activity on refractory organic matters in actual wastewater.

Stability test:

example 3 ozone catalytic Material after six reuses, medical BiochemicalCOD and NH of wastewater₄ ⁺The N removal rate was not significantly decreased (FIG. 6), but only decreased by 0.80% and 3.12%, at concentrations of 58.7 mg. multidot.L^-1And 5.43 mg. L^-1And the effluent does not detect Ce, Mn and Co ions, and meets the water supplement standards (60mg/L and 10mg/L) of an open type circulating cooling water system in the table 1 of quality of industrial water for recycling municipal sewage (GB/T19923-2005). The results show that the ozone catalytic material provided by the invention can quickly realize in-situ regeneration and adsorption of organic intermediates (organic carbon) or Cl^-Can be further decomposed or oxidized in the catalytic oxidation process of ozone, so that the catalytic active center can be regenerated, the regenerated microspheres repeat the adsorption-degradation process by virtue of the structure memory effect, active components are not lost in the whole catalytic reaction process, the catalytic activity is lasting and efficient, and the repeated use stability is good.

The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention.

Claims

1. The preparation method of the ozone catalytic material is characterized by comprising the following steps of:

immersing the solid material in an ammonium nitrate aqueous solution, carrying out water bath ultrasonic treatment for 0.5h, filtering, washing, drying in vacuum at 100-200 ℃ for 3-5 h, and then carrying out N at 400-600 DEG C₂Calcining for 2-4 hours in the atmosphere to obtain the ozone catalytic material;

the preparation method of the clean alumina comprises the following steps: alpha-Al is added₂O₃Soaking the raw materials in 1M hydrochloric acid and then 1M sodium hydroxide for 5h respectively, and then washing the raw materials to be neutral by deionized water;

the step gradient heating method specifically comprises the following steps: stage I, heating from room temperature to 200 ℃ at the speed of 10 ℃/min, and keeping the temperature for 2 hours; stage II, heating from 200 ℃ to 400 ℃ at a speed of 5 ℃/min, and preserving heat for 3 hours; stage III, cooling from 400 ℃ to 200 ℃ at the speed of 3 ℃/min, and naturally cooling to room temperature;

the mass fraction of the ammonium nitrate aqueous solution is 10 percent;

the metal nitrate is a mixture of manganese nitrate and cerium nitrate, and the molar ratio of manganese to cerium in the mixture of manganese nitrate and cerium nitrate is 7:3, 1:1 or 3: 7.

2. The method of claim 1, wherein the volume ratio of the clean alumina to the cobalt chloride solution is 1: 1.

3. The method of claim 1, wherein the mass ratio of the solid material to the aqueous ammonium nitrate solution is 1: 3.

4. An ozone catalytic material obtained by the production method according to any one of claims 1 to 3.