阅读说明：本技术 一种红壤热解制备异相芬顿催化剂的方法 (Method for preparing heterogeneous Fenton catalyst by red soil pyrolysis ) 是由 余丽 曹昉 卫皇曌 荣欣 赵颖 刘允康 于 2021-01-26 设计创作，主要内容包括：本发明属于催化技术领域,特别涉及一种红壤热解制备异相芬顿催化剂的方法,针对红壤不易耕种、异相芬顿催化剂成本高、活性组分铁易溶出等难题,本发明的制备方法是以红壤为原料,经醇洗、水洗、挤条成型、预氧化和炭化以及磷酸改性等过程制备出高催化性能和稳定性的新型异相芬顿催化剂,可促进过氧化氢的有效分解,产生充足羟基自由基,处理抗生素等难降解有机废水,具有良好的环境和经济效益。(The invention belongs to the technical field of catalysis, and particularly relates to a method for preparing an out-phase Fenton catalyst by red soil pyrolysis, aiming at the problems that the red soil is not easy to cultivate, the cost of the out-phase Fenton catalyst is high, an active component iron is easy to dissolve out and the like.)

1. A method for preparing a heterogeneous Fenton catalyst by red soil pyrolysis is characterized by comprising the following steps:

(1) naturally drying the red soil, grinding and sieving, pretreating with ethanol, washing with ultrapure water until the conductivity of leacheate is stable, vacuum-filtering the pretreated red soil to remove water, and drying;

(2) adding sesbania powder serving as a binder into the dried red soil, adding a phosphoric acid solution, mixing, and preparing into a cylindrical mixture by using forming equipment;

(3) placing the cylindrical mixture at room temperature, and drying; roasting in a carbonization converter, introducing air for a pre-oxidation process, then evacuating the air, filling nitrogen for a carbonization process, and naturally cooling to normal temperature after carbonization to obtain red soil carbon;

(4) the red soil carbon is dipped in phosphoric acid solution for modification, treated at room temperature under the sealing condition, washed by ultrapure water until the leacheate is neutral, and dried to obtain the modified red soil carbon which is used as the heterogeneous Fenton catalyst.

2. The method for preparing heterogeneous Fenton catalyst through red soil pyrolysis according to claim 1, wherein the red soil in the step (1) is red soil subclass in red soil, the natural air drying time is 5-7 days, and the grinding and sieving are 80-mesh sieve.

3. The method for preparing the heterogeneous Fenton catalyst through red soil pyrolysis according to claim 1, wherein ethanol in the step (1) is absolute ethanol, the drying temperature is 110-130 ℃, and the drying time is 12-24 hours.

4. The method for preparing the heterogeneous Fenton catalyst through red soil pyrolysis according to claim 1, wherein the adding amount of the sesbania powder in the step (2) is 3-6% of the mass of the dried red soil.

5. The method for preparing the heterogeneous Fenton catalyst through red soil pyrolysis according to claim 1, wherein the mass concentration of the phosphoric acid solution in the step (2) is 52-54%, and the adding amount of the phosphoric acid solution is 0.5-1% of the mass of the dried red soil.

6. The method for preparing the heterogeneous Fenton catalyst through red soil pyrolysis according to claim 1, wherein the forming device in the step (2) is a cylindrical extruder, the diameter of the cylindrical mixture is 1.5-2 mm, and the length of the cylindrical mixture is 2-3 mm.

7. The method for preparing the heterogeneous Fenton catalyst through red soil pyrolysis according to claim 1, wherein the standing time at room temperature in the step (3) is 12-24 hours, the drying temperature is 130-150 ℃, and the drying time is 24-48 hours.

8. The method for preparing the heterogeneous Fenton catalyst through red soil pyrolysis according to claim 1, wherein in the step (3), the red soil is roasted in a carbonization converter, air is firstly introduced to carry out a pre-oxidation process, then the air is exhausted, and nitrogen is filled to carry out a carbonization process, and the method comprises the following specific steps: firstly, introducing air at the air flow rate of 300-500 mL/min for pre-oxidation, heating the room temperature to 200-250 ℃ at the heating rate of 2-5 ℃/min, keeping the room temperature for 10 hours, exhausting air, introducing nitrogen at the nitrogen flow rate of 100-300 mL/min, heating the room temperature to 400-600 ℃, keeping the room temperature for 3-5 hours, and keeping the rotation speed of the carbonization converter at 5 r/min.

9. The method for preparing the heterogeneous Fenton catalyst through red soil pyrolysis according to claim 8, wherein the carbonization converter comprises a high-temperature electric heating furnace (1), a transmission motor (2), a transmission motor frequency converter (3), a support (4) and a reactor (5), the transmission motor (2) is electrically connected with the transmission motor frequency converter (3), the support is divided into a base (41) and a support frame (42), the base (41) is connected with one end of a support base (42) through a hinge, the other end of the support base is connected with a jack, the left side of the support frame (42) is used for supporting the high-temperature electric heating furnace (1), the right side of the support frame is used for supporting the transmission motor (2) and the transmission motor frequency converter (3), and the left side and the right side of the high-temperature electric heating furnace (1) are respectively provided with two limiting groove rollers (11);

the reactor (5) is placed in a high-temperature electric heating furnace (1) and comprises a reaction tube (51) and a pressing plate component (52), the right end opening of the reaction tube is sealed by a flange cover (6), a rotary joint (7) is arranged at the center of the flange cover (6) and used for connecting an air inlet pipe, a transmission ring (8) is arranged on the outer wall of the right end of the reaction tube (51), the transmission ring (8) is connected with a gear of a transmission motor (2) through a chain, limiting rings (9) are further arranged on the outer walls of the two ends of the reaction tube (51), the limiting rings (9) are embedded in limiting groove rollers (11), a fixed lug ring (10) is further arranged at the left end of the reaction tube (51), a hole plate (11) is arranged in the middle position inside the reaction tube (51), the hole plate (11) is formed by circular rings and laths which are uniformly arranged vertically and horizontally, a thermocouple sleeve (12) is arranged at the center of the hole plate (, the right side of orifice plate (11) is equipped with material turning plate (13), material turning plate (13) and reaction tube (51) inner wall fixed connection, the one corner of keeping away from reaction tube (51) inner wall of material turning plate (13) is the chamfer, clamp plate subassembly (52) comprises clamp plate (521), connecting rod (522), thermocouple well spacing sleeve (523), dead lever (524), clamp plate (521) are connected with dead lever (524) through connecting rod (522), the structure of clamp plate (521) is the same with orifice plate (11), the center of clamp plate (521) is equipped with thermocouple well perforation (14), the both ends of dead lever (524) are equipped with through-hole (15) and fixed earring (10) bolted connection, thermocouple well spacing sleeve (523) sets up on dead lever (524), and thermocouple well spacing sleeve (523), thermocouple well perforation (14), The central axis of the pore plate (11) is on the same horizontal line, and a layer of porous filler is sandwiched between the pore plate (11) and the pressing plate (521) according to the size of the materials, so that the leakage of the reaction materials is avoided.

10. The method for preparing the heterogeneous Fenton catalyst through red soil pyrolysis according to claim 1, wherein the mass concentration of the phosphoric acid solution in the step (4) is 52-54%; the room temperature treatment time is 20-30 h; the drying temperature is 130-150 ℃, and the drying time is 24-48 h.

Technical Field

The invention belongs to the technical field of catalysis, and particularly relates to a method for preparing a heterogeneous Fenton catalyst by red soil pyrolysis.

Background

Antibiotics are chemicals produced by the metabolism of a class of microorganisms that kill other microorganisms. Due to the inhibition effect of antibiotic on pathogenic microorganisms, the antibiotic is widely applied to the industries of medical treatment, livestock raising, aquaculture and the like. The hospital wastewater is discharged after being treated by a sewage treatment plant or a sewage treatment station, and because the main process of most sewage treatment plants is a biochemical treatment method, the antibiotic removal effect is weak, and the antibiotic can still be detected in the treated wastewater. The aquaculture industry uses a large amount of antibiotics for fishes, and part of the antibiotics are eaten by the fishes and enter a water body along with excrement, while the part which is not eaten by the fishes directly enters the water body, so that the water body is polluted. The wastewater discharged in the pharmaceutical process contains a plurality of high-concentration active antibiotics, which have serious influence on the environment and ecology due to the difficult degradability. The antibiotic wastewater pollutants have complex components, contain non-degradable organic matters such as unreacted raw materials, drug intermediates, organic solvents and the like, and have strong biological inhibition effect on the wastewater, so that the biodegradability of the wastewater is poor.

The treatment method of the waste water comprises the technologies of physical and chemical treatment, biochemical treatment, advanced oxidation and the like, wherein strong oxidation substances can be generated in the advanced oxidation process, and organic pollutants can be effectively degraded. The Fenton oxidation method is widely applied to antibiotic wastewater treatment, and has the advantages of mild reaction conditions, simple equipment, no secondary pollution and the like. But Fe in homogeneous Fenton²⁺Can lead to the wasting of resources and secondary pollution along with arranging water and run off, and need adjust pH, consume a large amount of acid-base solution, can produce a large amount of iron mud in waste water treatment process, need further processing. In the heterogeneous Fenton method, iron exists in a solid phase, so that the service life of the catalyst is prolonged, the catalyst is not easy to run off, and the catalyst can be repeatedly used. The development of a novel heterogeneous Fenton catalyst is particularly important, and the novel Fenton technology is promoted to be more environment-friendly and efficiently applied to large-scale industrial wastewater treatment.

Red soil develops in the soil under the vegetation of tropical and subtropical rainforests, seasonal rainforests or evergreen broadleaf forests, is deficient in alkali metals and alkaline earth metals and is rich in iron and aluminum oxides. The pH value is 4.0-5.5, and the pH value is acidic. The organic content is less than 20g/kg, and the tiltability is poor. However, from another point of view, the red soil contains rich iron minerals, if the red soil is pyrolyzed and carbonized to prepare red soil carbon, iron is fixed in a carbon-based structure to serve as an active component of heterogeneous Fenton, on one hand, a low-cost and high-efficiency heterogeneous Fenton catalyst can be developed, and on the other hand, a new way is provided for resource utilization of barren red soil.

Disclosure of Invention

Aiming at the problems that red soil is not easy to cultivate, the heterogeneous Fenton catalyst is high in cost, the active component iron is easy to dissolve out and the like, the invention provides a method for preparing the heterogeneous Fenton catalyst by red soil pyrolysis.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method for preparing a heterogeneous Fenton catalyst by red soil pyrolysis comprises the following steps:

(1) naturally drying the red soil, grinding and sieving, pretreating with ethanol, washing with ultrapure water until the conductivity of leacheate is stable, vacuum-filtering the pretreated red soil to remove water, and drying;

(2) adding sesbania powder serving as a binder into the dried red soil, adding a phosphoric acid solution, mixing, and preparing into a cylindrical mixture by using forming equipment;

(3) placing the cylindrical mixture at room temperature, and drying; roasting in a carbonization converter, introducing air for a pre-oxidation process, then evacuating the air, filling nitrogen for a carbonization process, and naturally cooling to normal temperature after carbonization to obtain red soil carbon;

(4) the red soil carbon is dipped in phosphoric acid solution for modification, treated at room temperature under the sealing condition, washed by ultrapure water until the leacheate is neutral, and dried to obtain the modified red soil carbon which is used as the heterogeneous Fenton catalyst.

Further, the red soil in the step (1) is a red soil subclass in red soil, the natural air drying time is 5-7 days, and the grinding and sieving are 80-mesh sieves.

Further, the ethanol in the step (1) is absolute ethanol, the drying temperature is 110-130 ℃, and the drying time is 12-24 hours.

Further, the adding amount of the sesbania powder in the step (2) is 3-6% of the mass of the dried red soil.

Further, in the step (2), the mass concentration of the phosphoric acid solution is 52-54%, and the adding amount of phosphoric acid is 0.5-1% of the mass of the dried red soil.

Further, the forming equipment in the step (2) is a cylindrical extruder, the diameter of the cylindrical mixture is 1.5-2 mm, and the length of the cylindrical mixture is 2-3 mm.

Further, in the step (3), the standing time at room temperature is 12-24 hours, the drying temperature is 130-150 ℃, and the drying time is 24-48 hours.

Further, roasting in the carbonization converter in the step (3), introducing air firstly for a pre-oxidation process, then emptying the air, filling nitrogen for a carbonization process, and specifically: firstly, introducing air at the air flow rate of 300-500 mL/min for pre-oxidation, heating the room temperature to 200-250 ℃ at the heating rate of 2-5 ℃/min, keeping the room temperature for 10 hours, exhausting air, introducing nitrogen at the nitrogen flow rate of 100-300 mL/min, heating the room temperature to 400-600 ℃, and keeping the room temperature for 3-5 hours; the rotating speed of the carbonization converter is 5 r/min.

Furthermore, the carbonization converter comprises a high-temperature electric heating furnace, a transmission motor frequency converter, a support and a reactor, wherein the transmission motor is electrically connected with the transmission motor frequency converter, the support is divided into a base and a support frame, one end of the base is connected with one end of a support seat through a hinge, the other end of the base is connected with the other end of the support seat through a jack, the left side of the support frame is used for supporting the high-temperature electric heating furnace, the right side of the support frame is used for supporting the transmission motor and the transmission motor frequency converter, and the left side and the right side of;

the reactor is placed in a high-temperature electric heating furnace and comprises a reaction tube and a pressing plate assembly, the right end opening of the reaction tube is sealed by a flange cover, a rotary joint is arranged in the center of the flange cover and used for connecting an air inlet pipe, a transmission ring is arranged on the outer wall of the right end of the reaction tube and connected with a gear of a transmission motor through a chain, limiting rings are further arranged on the outer walls of the two ends of the reaction tube and embedded in limiting groove rollers, a fixing lug ring is further arranged at the left end of the reaction tube, a hole plate is arranged in the middle of the inside of the reaction tube and consists of circular rings and laths which are uniformly arranged in a vertical and horizontal mode, a thermocouple sleeve is arranged in the center of the hole plate, a material turning plate is arranged on the right side of the hole plate and fixedly connected with the inner wall of the reaction tube, one corner of the material turning plate, which is, Connecting rod, thermocouple well casing limit sleeve, dead lever constitute, the clamp plate passes through the connecting rod and is connected with the dead lever, the structure of clamp plate is the same with the orifice plate, and the center of clamp plate is equipped with the thermocouple well casing and perforates, the both ends of dead lever are equipped with through-hole and fixed earring bolted connection, thermocouple well casing limit sleeve sets up on the dead lever, and the central axis of thermocouple well casing limit sleeve, thermocouple well casing perforation, orifice plate is on same water flat line, press from both sides the poroid filler of one deck according to the material size between orifice plate and the clamp plate, avoid reaction material to spill.

Further, the mass concentration of the phosphoric acid solution in the step (4) is 52-54%; the room temperature treatment time is 20-30 h; the drying temperature is 130-150 ℃, and the drying time is 24-48 h.

Compared with the prior art, the invention has the following advantages:

1. the heterogeneous Fenton catalysts on the market are additionally loaded with iron as an active component and metal oxides such as Al₂O₃And the like or non-metallic carriers such as graphene, biochar and the like are used as carriers, and one or more defects exist, such as complex preparation method, high preparation cost, poor stability of active components and the like. The red soil is used as a raw material, and the red soil is rich in iron minerals (as shown in table 1, the iron content in the dry red soil DR is 3.677 wt.%) and has various forms such as ferric oxide, ferrous oxide, ferroferric oxide and the like. The ethanol is used for pretreatment, so that red soil is prevented from caking during drying treatment, and the properties of the formed catalyst are uniform. In the carbonization processIn the method, the iron element is embedded into the carbon matrix and is used as an active component of the catalyst, so that the iron element is not easy to run off, and the existence of various forms of iron is favorable for accelerating the iron circulation process of the Fenton reaction. Table 1 lists the chemical compositions and physical properties such as specific surface area, pore volume and pore diameter of red soil and red soil carbon.

TABLE 1

Note: DR is dry red soil; RC-0 is unmodified red soil carbon; RC-1 is modified red soil carbon without a pre-oxidation process; RC-2 is the red soil carbon of the invention, namely the red soil carbon which is modified by phosphoric acid through a pre-oxidation process.

2. The pyrolysis carbon materials on the market or in the prior literature are basically carbonized directly or carbonized after simple pretreatment, and in the subsequent modification process, active components exist in ash and are lost along with the dissolution of the ash, so that the activity of the catalyst is reduced. The preparation method of the invention, which is to pre-oxidize the red soil and then carbonize the red soil, has three advantages: the valence state of metal in the red soil and the combination form of the metal, carbon, oxygen and other elements are changed by pre-oxidation, the stability of iron in a carbon matrix is enhanced (the iron content of RC-2 in table 1 is up to 5.914 wt%, which is far higher than that of a catalyst without additionally carrying iron on the market), and the valence state and the combination form of iron on the surface of the catalyst are enriched; secondly, the generation of various oxygen-containing functional groups on the surface of the red soil carbon is promoted, the combination with the characteristic structure of antibiotics is facilitated, for example, the pi-pi combination is carried out on the benzene ring structures in cefalexin and levofloxacin, and the oxidative degradation of free radicals on the surface of the catalyst is promoted; ③ the specific surface area of the modified catalyst is increased, as shown in Table 1, the specific surface area of RC-2 is increased by 36.3 percent compared with that of RC-1, the pore volume is increased by 19.8 percent, and the reaction sites are increased.

3. The carbonization converter adopted by the invention is an autonomously designed carbonization converter, the specific structural schematic diagram and the material object diagram are shown in figures 1, 2, 3, 4 and 5, the carbonization converter is adopted to pre-oxidize and carbonize red soil, the effect is better than that of the traditional fixed tube furnace, a material turning plate is arranged in a constant temperature area of a reaction tube, when the reactor rotates, the material turning plate can continuously turn over the material, so that the material is heated more uniformly, and the material can be fully contacted with reaction gas. The front end of the bracket is provided with a jack which can enable the reaction furnace to incline at a certain angle and enable the reaction materials to be always at the constant temperature section position of the heating furnace. The raw materials for preparing the catalyst are directly put into a quartz reactor, a crucible is not used, the heat transfer resistance is reduced, the rotating speed of 5r/min is adopted, the red soil is uniformly heated in the carbonization process, volatile components are uniformly escaped, the carbonization process is stable, and the obtained red soil carbon has uniform properties.

4. The specific surface area, the pore volume and the like of the red soil carbon catalyst are effectively increased by modifying the performance with a phosphoric acid solution with the mass concentration of 52-54%. As shown in Table 1, the specific surface area of RC-2 is 6.6 times that of the unmodified red soil carbon RC-0. The prior art reports that the effect of the nitric acid modification pretreatment is good, but the strength is greatly reduced. The oxidation of the phosphoric acid used by the method is not like that of nitric acid, and the method is carried out at room temperature, so that the strength of the catalyst can be effectively ensured, the service life of the catalyst is prolonged, and the method is favorable for recycling.

The invention aims to provide a low-cost and high-efficiency preparation method of an out-phase Fenton catalyst aiming at the problems that antibiotic wastewater is difficult to treat and the out-phase Fenton catalyst on the market is high in cost or low in efficiency, creatively utilizes red soil which is rich in iron minerals and poor in culturability as a raw material, and simultaneously solves the problems that the value is low and the like caused by the treatment of the refractory organic wastewater such as antibiotics and the poor culturability of the barren red soil.

Drawings

FIG. 1 is a schematic view of the structure of a carbonization converter of the present invention;

FIG. 2 is a schematic view showing the structure of a reactor of the carbonization converter of the present invention;

FIG. 3 is a schematic view showing the structure of a reaction tube of the carbonization converter of the invention;

FIG. 4 is a schematic structural view of a platen assembly of the carbonization converter of the present invention;

FIG. 5 is a diagram of a carbonization converter;

FIG. 6 is a schematic view of an antibiotic wastewater treatment apparatus.

Detailed Description

The following examples are further illustrative of the present invention and are not intended to be limiting thereof.

Example 1:

a heterogeneous Fenton catalyst prepared by red soil pyrolysis is prepared by the following steps:

(1) naturally drying the red soil for 7 days, grinding the red soil, sieving the red soil by using a 80-mesh sieve, pretreating the red soil by using absolute ethyl alcohol, washing the red soil by using ultrapure water until the conductivity of leacheate is stable, removing moisture from the pretreated red soil by using vacuum filtration, and drying the red soil for 24 hours in an oven at 120 ℃;

(2) adding sesbania powder accounting for 4% of the dry red soil by mass as a binder, adding phosphoric acid with the mass concentration of 52% for mixing, wherein the adding amount of the phosphoric acid solution is 0.6% of the mass of the dry red soil, and preparing a cylindrical mixture by using a strip extruding machine forming device (SET-100), wherein the size of the obtained cylindrical mixture is 1.5-2 mm in diameter and 2-3 mm in length;

(3) placing the cylindrical mixture for 24 hours at room temperature, then placing the cylindrical mixture in an oven at the temperature of 150 ℃ for drying for 24 hours, roasting the cylindrical mixture in a carbonization converter, introducing air at the air flow rate of 300mL/min for pre-oxidation, heating the cylindrical mixture to 250 ℃ at the heating rate of 3 ℃/min, keeping the temperature for 10 hours, then exhausting the air, introducing nitrogen at the nitrogen flow rate of 200mL/min, heating the cylindrical mixture to 500 ℃ and keeping the temperature for 4 hours, wherein the rotation speed of the carbonization converter is 5r/min, and naturally cooling the cylindrical mixture to the normal temperature after carbonization to obtain the red soil carbon;

the carbonization converter comprises a high-temperature electric heating furnace 1(YKRL type), a transmission MOTOR 2(3-PHASE GEAR MOTOR), a transmission MOTOR frequency converter 3(E390-A), a support 4 and a reactor 5, wherein the high-temperature electric heating furnace 1 adopts a silicon carbide rod as a heating element and is provided with a platinum-rhodium thermocouple, so that the reaction temperature can reach 800 ℃; the reactor 5 is made of 310S stainless steel, has good oxidation resistance, corrosion resistance, high temperature resistance and other properties, and the highest service temperature can reach 1200 ℃; the bracket 4 is made of carbon steel material; the high-temperature electric heating furnace is characterized in that the transmission motor 2 is electrically connected with the transmission motor frequency converter 3, the support is divided into a base 41 and a support frame 42, one end of the base 41 is connected with one end of the support base 42 through a hinge, the other end of the base 41 is connected with a jack, so that the carbonization converter can incline for a certain angle (0-5 degrees), the left side of the support frame 42 is used for supporting the high-temperature electric heating furnace 1, the right side of the support frame is used for supporting the transmission motor 2 and the transmission motor frequency converter 3, and the left side and the right side of the high-temperature;

the reactor 5 is placed in the high-temperature electric heating furnace 1 and comprises a reaction tube 51 and a pressure plate component 52, the right end opening of the reaction tube is sealed by a flange cover 6, a rotary joint 7 is arranged at the center of the flange cover 6 and used for connecting an air inlet pipe, the air inlet pipe cannot rotate along with the reactor when the reactor 5 rotates, a transmission ring 8 is arranged on the outer wall of the right end of the reaction tube 51, the transmission ring 8 is connected with a gear of a transmission motor 2 through a chain, limiting rings 9 are further arranged on the outer walls of two ends of the reaction tube 51, the limiting rings 9 are embedded in limiting groove rollers 11, when the reactor 5 rotates, the position of the reactor 5 cannot be changed, a fixed lug ring 10 is further arranged at the left end of the reaction tube 51, a pore plate 11 is arranged at the middle position inside the reaction tube 51 and used for supporting reaction materials, so that the reaction materials are always located at a constant temperature section of the heating furnace, the pore plate 11 is composed of circular rings and laths which are uniformly arranged in a longitudinal and transverse direction, the center of the pore plate 11 is provided with a thermocouple sleeve 12, a thermocouple is placed in the thermocouple sleeve 12, the right side of the pore plate 11 is provided with a material turning plate 13, when the reactor 5 rotates, the material turning plate 13 can continuously turn over the material to ensure that the material is heated more uniformly, and simultaneously the material can be fully contacted with reaction gas, the material turning plate 13 is fixedly connected with the inner wall of the reaction tube 51, one corner of the material turning plate 13, which is far away from the inner wall of the reaction tube 51, is a chamfer, the pressure plate assembly 52 is composed of a pressure plate 521, a connecting rod 522, a thermocouple sleeve limiting sleeve 523 and a fixed rod 524, the pressure plate 521 is connected with the fixed rod 524 through the connecting rod 522, the structure of the pressure plate 521 is the same as that of the pore plate 11, the center of the pressure plate, the thermocouple well limiting sleeve 523 is arranged on the fixing rod 524, the central axes of the thermocouple well limiting sleeve 523, the thermocouple well perforation 14 and the pore plate 11 are on the same horizontal line, so that the thermocouple well in the reaction tube 51 can be kept horizontal, and a layer of porous filler is sandwiched between the pore plate 11 and the pressure plate 521 according to the size of the material, so that the reaction material is prevented from leaking;

(4) soaking the red soil carbon in a phosphoric acid solution with the mass concentration of 52% for modification, and treating for 24 hours at room temperature under a sealed condition; and (3) rinsing with ultrapure water until the leacheate is neutral, drying in an oven at the drying temperature of 150 ℃ for 24 hours to obtain modified red soil carbon RC-2(1) serving as the heterogeneous Fenton catalyst after cooling.

The application comprises the following steps: the actual wastewater of a certain hospital is taken as a treatment object, the wastewater sequentially passes through a fine grating, an adjusting tank, ultrafiltration and an out-phase Fenton reaction coupling process, and a schematic diagram of a treatment device is shown in figure 6. Wherein, the heterogeneous Fenton reaction conditions are as follows: the temperature is 60 ℃, the pH is 3, 1kg/t (30 wt.%) of hydrogen peroxide and the space velocity of the reactor is 1h^-1The catalyst is red soil carbon RC-2(1) prepared in the embodiment (1) of the invention. Control experiments were set up, i.e. no catalyst was added during the heterogeneous fenton reaction phase. The water quality analysis and detection items of inlet and outlet water comprise Chemical Oxygen Demand (COD), Total Organic Carbon (TOC), cephalexin, resistance genes and the like. After the catalyst was added, the treatment apparatus was allowed to run stably for a period of time until the effluent quality was stable, and the table 2 was recorded.

TABLE 2

Example 2:

a heterogeneous Fenton catalyst prepared by red soil pyrolysis is prepared by the following steps:

(1) naturally drying the red soil for 7 days, grinding the red soil, sieving the red soil by using a 80-mesh sieve, pretreating the red soil by using absolute ethyl alcohol, washing the red soil by using ultrapure water until the conductivity of leacheate is stable, removing water from the pretreated red soil by using vacuum filtration, and drying the red soil in an oven at 130 ℃ for 15 hours;

(2) adding sesbania powder accounting for 5% of the dry red soil by mass as a binder, adding 53% of phosphoric acid by mass concentration, mixing, wherein the adding amount of the phosphoric acid solution is 0.5% of the dry red soil by mass, and preparing a cylindrical mixture by using a strip extruding machine forming device (SET-100), wherein the size of the obtained cylindrical mixture is 1.5-2 mm in diameter and 2-3 mm in length;

(3) placing the cylindrical mixture at room temperature for 18h, then placing the cylindrical mixture in an oven at the temperature of 130 ℃ for drying for 48h, roasting the cylindrical mixture in a carbonization converter, firstly introducing air at the air flow rate of 400mL/min for pre-oxidation, heating the cylindrical mixture to 250 ℃ at the heating rate of 4 ℃/min, keeping the temperature for 10h, then exhausting the air, introducing nitrogen at the nitrogen flow rate of 300mL/min, heating the cylindrical mixture to 600 ℃, keeping the temperature for 3h, wherein the rotation speed of the carbonization converter is 5r/min, and the carbonization converter is the same as the embodiment 1, and naturally cooling to the normal temperature after carbonization to obtain the red soil carbon;

(4) soaking the red soil carbon in a phosphoric acid solution with the mass concentration of 53% for modification, and treating for 20 hours at room temperature under a sealed condition; and (3) rinsing with ultrapure water until the leacheate is neutral, drying in an oven at the drying temperature of 130 ℃ for 30 hours to obtain modified red soil carbon RC-2(2) serving as the heterogeneous Fenton catalyst after cooling.

The application comprises the following steps: the actual wastewater of a certain hospital is taken as a treatment object, the wastewater sequentially passes through a fine grating, an adjusting tank, ultrafiltration and an out-phase Fenton reaction coupling process, and a schematic diagram of a treatment device is shown in figure 6. Wherein, the heterogeneous Fenton reaction conditions are as follows: the temperature is 60 ℃, the pH is 3, 1kg/t (30 wt.%) of hydrogen peroxide and the space velocity of the reactor is 1h^-1The catalyst is red soil carbon RC-2(2) prepared in the embodiment (2) of the invention. Control experiments were set up, i.e. no catalyst was added during the heterogeneous fenton reaction phase. The water quality analysis and detection items of inlet and outlet water comprise Chemical Oxygen Demand (COD), Total Organic Carbon (TOC), cephalexin, resistance genes and the like. After the catalyst was added, the treatment apparatus was allowed to run stably for a period of time until the effluent quality was stable, which is recorded in table 3.

TABLE 3

Example 3:

a heterogeneous Fenton catalyst prepared by red soil pyrolysis is prepared by the following steps:

(1) naturally drying the red soil for 7 days, grinding the red soil, sieving the red soil by using a 80-mesh sieve, pretreating the red soil by using absolute ethyl alcohol, washing the red soil by using ultrapure water until the conductivity of leacheate is stable, removing moisture from the pretreated red soil by using vacuum filtration, and drying the red soil for 24 hours in an oven at 120 ℃;

(2) adding sesbania powder accounting for 3% of the dry red soil by mass as a binder, adding phosphoric acid with the mass concentration of 54% for mixing, wherein the adding amount of the phosphoric acid solution is 0.8% of the mass of the dry red soil, and preparing a cylindrical mixture by using a strip extruding machine forming device (SET-100), wherein the size of the obtained cylindrical mixture is 1.5-2 mm in diameter and 2-3 mm in length;

(3) placing the cylindrical mixture for 24 hours at room temperature, then placing the cylindrical mixture in an oven with the temperature of 140 ℃ for drying for 36 hours, roasting the cylindrical mixture in a carbonization converter, introducing air at the air flow rate of 500mL/min for pre-oxidation, raising the temperature to 250 ℃ at the temperature raising rate of 5 ℃/min, keeping the temperature for 10 hours, then exhausting the air, introducing nitrogen at the nitrogen flow rate of 280mL/min, raising the temperature to 550 ℃ and keeping the temperature for 3 hours, wherein the rotation speed of the carbonization converter is 5r/min, and the carbonization converter is the same as the embodiment 1 and naturally cools to the normal temperature after carbonization to obtain the red soil carbon;

(4) soaking the red soil carbon in a phosphoric acid solution with the mass concentration of 54% for modification, and treating for 20 hours at room temperature under a sealed condition; and (3) rinsing with ultrapure water until the leacheate is neutral, drying in an oven at the drying temperature of 130 ℃ for 48 hours to obtain the modified red soil carbon RC-2(3) serving as the heterogeneous Fenton catalyst after cooling.

The application comprises the following steps: the actual wastewater of a certain hospital is taken as a treatment object, the wastewater sequentially passes through a fine grating, an adjusting tank, ultrafiltration and an out-phase Fenton reaction coupling process, and a schematic diagram of a treatment device is shown in figure 6. Wherein, the heterogeneous Fenton reaction conditions are as follows: the temperature is 60 ℃, the pH is 3, 1kg/t (30 wt.%) of hydrogen peroxide and the space velocity of the reactor is 1h^-1The catalyst is red soil carbon RC-2(3) prepared in the embodiment (3) of the invention. Control experiments were set up, i.e. no catalyst was added during the heterogeneous fenton reaction phase. The water quality analysis and detection items of inlet and outlet water comprise Chemical Oxygen Demand (COD), Total Organic Carbon (TOC), cephalexin, resistance genes and the like. After the catalyst is added, let to treatThe device stably operates for a period of time until the effluent quality is stable, and the table 4 is recorded.

TABLE 4

Example 4:

a heterogeneous Fenton catalyst prepared by red soil pyrolysis is prepared by the following steps:

(1) naturally drying the red soil for 5 days, grinding the red soil, sieving the red soil by using a 80-mesh sieve, pretreating the red soil by using absolute ethyl alcohol, washing the red soil by using ultrapure water until the conductivity of leacheate is stable, removing water from the pretreated red soil by using vacuum filtration, and drying the red soil in a drying oven at 110 ℃ for 12 hours;

(2) adding sesbania powder accounting for 6% of the dry red soil by mass as a binder, adding phosphoric acid with the mass concentration of 53% for mixing, wherein the adding amount of the phosphoric acid solution is 1% of the mass of the dry red soil, and preparing a cylindrical mixture by using a strip extruding machine forming device (SET-100), wherein the size of the obtained cylindrical mixture is 1.5-2 mm in diameter and 2-3 mm in length;

(3) placing the cylindrical mixture at room temperature for 12h, then placing the cylindrical mixture in an oven at the temperature of 130 ℃ for drying for 48h, roasting the cylindrical mixture in a carbonization converter, firstly introducing air at the air flow rate of 400mL/min for pre-oxidation, heating the cylindrical mixture to 200 ℃ at the heating rate of 2 ℃/min, keeping the temperature for 10h, then exhausting the air, introducing nitrogen at the nitrogen flow rate of 100mL/min, heating the cylindrical mixture to 400 ℃ and keeping the temperature for 5h, wherein the rotation speed of the carbonization converter is 5r/min, and the carbonization converter is the same as the embodiment 1, and naturally cooling to the normal temperature after carbonization to obtain the red soil carbon;

(4) soaking the red soil carbon in a phosphoric acid solution with the mass concentration of 53% for modification, and treating for 30 hours at room temperature under a sealed condition; and (3) rinsing with ultrapure water until the leacheate is neutral, drying in an oven at the drying temperature of 140 ℃ for 30 hours to obtain modified red soil carbon RC-2(4) serving as the heterogeneous Fenton catalyst after cooling.

The application comprises the following steps: the actual wastewater of a certain hospital is taken as a treatment object, and the wastewater sequentially passes throughFine grating, adjusting tank, ultrafiltration and out-phase Fenton reaction coupling process, and the schematic diagram of the treatment device is shown in figure 6. Wherein, the heterogeneous Fenton reaction conditions are as follows: the temperature is 60 ℃, the pH is 3, 1kg/t (30 wt.%) of hydrogen peroxide and the space velocity of the reactor is 1h^-1The catalyst is red soil carbon RC-2(4) prepared in the embodiment (4) of the invention. Control experiments were set up, i.e. no catalyst was added during the heterogeneous fenton reaction phase. The water quality analysis and detection items of inlet and outlet water comprise Chemical Oxygen Demand (COD), Total Organic Carbon (TOC), cephalexin, resistance genes and the like. After the catalyst was added, the treatment apparatus was allowed to run stably for a period of time until the effluent quality was stable, and the results are recorded in Table 5.

TABLE 5

Example 5:

a heterogeneous Fenton catalyst prepared by red soil pyrolysis is prepared by the following steps:

(1) naturally drying the red soil for 6 days, grinding the red soil, sieving the red soil by a sieve of 80 meshes, pretreating the red soil by absolute ethyl alcohol, washing the red soil by ultrapure water until the conductivity of leacheate is stable, removing water from the pretreated red soil by vacuum filtration, and drying the red soil in a drying oven at 110 ℃ for 12 hours;

(2) adding sesbania powder accounting for 6% of the dry red soil by mass as a binder, adding phosphoric acid with the mass concentration of 53% for mixing, wherein the adding amount of the phosphoric acid solution is 1% of the mass of the dry red soil, and preparing a cylindrical mixture by using a strip extruding machine forming device (SET-100), wherein the size of the obtained cylindrical mixture is 1.5-2 mm in diameter and 2-3 mm in length;

(3) placing the cylindrical mixture at room temperature for 12h, then placing the cylindrical mixture in an oven at the temperature of 130 ℃ for drying for 48h, roasting the cylindrical mixture in a carbonization converter, firstly introducing air at the air flow rate of 400mL/min for pre-oxidation, heating the cylindrical mixture to 230 ℃ at the heating rate of 2 ℃/min, keeping the temperature for 10h, then exhausting the air, introducing nitrogen at the nitrogen flow rate of 100mL/min, heating the cylindrical mixture to 400 ℃ and keeping the temperature for 5h, wherein the rotation speed of the carbonization converter is 5r/min, and the carbonization converter is the same as the embodiment 1, and naturally cooling to the normal temperature after carbonization to obtain the red soil carbon;

(4) soaking the red soil carbon in a phosphoric acid solution with the mass concentration of 53% for modification, and treating for 20 hours at room temperature under a sealed condition; and (3) rinsing with ultrapure water until the leacheate is neutral, drying in an oven at the drying temperature of 130 ℃ for 30 hours to obtain modified red soil carbon RC-2(5) serving as the heterogeneous Fenton catalyst after cooling.

The application comprises the following steps: the actual wastewater of a certain hospital is taken as a treatment object, the wastewater sequentially passes through a fine grating, an adjusting tank, ultrafiltration and an out-phase Fenton reaction coupling process, and a schematic diagram of a treatment device is shown in figure 6. Wherein, the heterogeneous Fenton reaction conditions are as follows: the temperature is 60 ℃, the pH is 3, 1kg/t (30 wt.%) of hydrogen peroxide and the space velocity of the reactor is 1h^-1The catalyst is red soil carbon RC-2(5) prepared in the embodiment (5) of the invention. Control experiments were set up, i.e. no catalyst was added during the heterogeneous fenton reaction phase. The water quality analysis and detection items of inlet and outlet water comprise Chemical Oxygen Demand (COD), Total Organic Carbon (TOC), cephalexin, resistance genes and the like. After the catalyst was added, the treatment apparatus was allowed to run stably for a while until the effluent quality was stable, and the results are recorded in Table 6.

TABLE 6

Example 6:

a heterogeneous Fenton catalyst prepared by red soil pyrolysis is prepared by the following steps:

(1) naturally drying the red soil for 7 days, grinding the red soil, sieving the red soil by using a 80-mesh sieve, pretreating the red soil by using absolute ethyl alcohol, washing the red soil by using ultrapure water until the conductivity of leacheate is stable, removing moisture from the pretreated red soil by using vacuum filtration, and drying the red soil for 24 hours in an oven at 120 ℃;

(2) adding sesbania powder accounting for 4% of the mass of the dried red soil into the dried red soil as a binder, adding phosphoric acid with the mass concentration of 52% into the dried red soil for mixing, wherein the adding amount of the phosphoric acid solution is 0.6% of the mass of the dried red soil, and preparing a cylindrical mixture by using a strip extruding machine forming device (SET-100), wherein the size of the obtained cylindrical mixture is 1.5-2 mm in diameter and 2-3 mm in length;

(3) placing the cylindrical mixture for 24 hours at room temperature, then placing the cylindrical mixture in an oven with the temperature of 150 ℃ for drying for 24 hours, roasting the cylindrical mixture in a carbonization converter, directly entering a carbonization process without an air pre-oxidation process, introducing nitrogen at the nitrogen flow rate of 200mL/min, raising the temperature to 500 ℃ at the temperature raising rate of 3 ℃/min, keeping the temperature for 4 hours, and keeping the rotation speed of the carbonization converter at 5r/min, wherein the carbonization converter is the same as the embodiment 1, and naturally cooling to the normal temperature after carbonization to obtain the red soil carbon;

(4) soaking the red soil carbon in a phosphoric acid solution with the mass concentration of 52% for modification, and treating for 24 hours at room temperature under a sealed condition; and (3) washing with ultrapure water until the leacheate is neutral, drying in an oven at the drying temperature of 150 ℃ for 24 hours to obtain the modified red soil carbon RC-1 serving as the heterogeneous Fenton catalyst after cooling.

The application comprises the following steps: the actual wastewater of a certain hospital is taken as a treatment object, the wastewater sequentially passes through a fine grating, an adjusting tank, ultrafiltration and an out-phase Fenton reaction coupling process, and a schematic diagram of a treatment device is shown in figure 6. Wherein, the heterogeneous Fenton reaction conditions are as follows: the temperature is 60 ℃, the pH is 3, 1kg/t (30 wt.%) of hydrogen peroxide and the space velocity of the reactor is 1h^-1The red soil carbon RC-1 prepared in the embodiment (4) of the invention is adopted as the catalyst. Control experiments were set up, i.e. no catalyst was added during the heterogeneous fenton reaction phase. The water quality analysis and detection items of inlet and outlet water comprise Chemical Oxygen Demand (COD), Total Organic Carbon (TOC), cephalexin, resistance genes and the like. After the catalyst was added, the treatment apparatus was allowed to run stably for a while until the effluent quality was stable, and the results are recorded in Table 7.

TABLE 7

Example 7:

a heterogeneous Fenton catalyst prepared by red soil pyrolysis is prepared by the following steps:

(1) naturally drying the red soil for 7 days, grinding the red soil, sieving the red soil by using a 80-mesh sieve, pretreating the red soil by using absolute ethyl alcohol, washing the red soil by using ultrapure water until the conductivity of leacheate is stable, removing moisture from the pretreated red soil by using vacuum filtration, and drying the red soil for 24 hours in an oven at 120 ℃;

(2) adding sesbania powder accounting for 4% of the dry red soil by mass as a binder, adding phosphoric acid with the mass concentration of 52% for mixing, wherein the adding amount of the phosphoric acid solution is 0.6% of the mass of the dry red soil, and preparing a cylindrical mixture by using a strip extruding machine forming device (SET-100), wherein the size of the obtained cylindrical mixture is 1.5-2 mm in diameter and 2-3 mm in length;

(3) placing the cylindrical mixture for 24 hours at room temperature, then placing the cylindrical mixture in an oven with the temperature of 150 ℃ for drying for 24 hours, roasting the cylindrical mixture in a carbonization converter, wherein the heating rate is 3 ℃/min, firstly introducing air for carrying out a pre-oxidation process, the air flow rate is 300mL/min, heating the cylindrical mixture from the room temperature to 250 ℃, keeping the temperature for 10 hours, then evacuating the air, filling nitrogen for carrying out a carbonization process, the nitrogen flow rate is 200mL/min, heating the cylindrical mixture to 500 ℃, keeping the temperature for 4 hours, the rotation speed of the carbonization converter is 5r/min, naturally cooling the carbonized mixture to the normal temperature to obtain the red soil carbon RC-0, and performing no phosphoric acid modification to obtain the red soil carbon RC-.

The application comprises the following steps: the actual wastewater of a certain hospital is taken as a treatment object, the wastewater sequentially passes through a fine grating, an adjusting tank, ultrafiltration and an out-phase Fenton reaction coupling process, and a schematic diagram of a treatment device is shown in figure 6. Wherein, the heterogeneous Fenton reaction conditions are as follows: the temperature is 60 ℃, the pH is 3, 1kg/t (30 wt.%) of hydrogen peroxide and the space velocity of the reactor is 1h^-1The red soil carbon RC-0 prepared in the embodiment (5) of the invention is adopted as the catalyst. Control experiments were set up, i.e. no catalyst was added during the heterogeneous fenton reaction phase. The water quality analysis and detection items of inlet and outlet water comprise Chemical Oxygen Demand (COD), Total Organic Carbon (TOC), cephalexin, resistance genes and the like. After the catalyst was added, the treatment apparatus was allowed to run stably for a while until the effluent quality was stable, and the table 8 was recorded.

TABLE 8

As can be seen from the specific examples, examples 1, 2, 3, 4 and 5 were prepared according to the preparation method of the present inventionThe obtained red soil heterogeneous Fenton catalyst RC-2. Hospital wastewater can be effectively treated by adding an out-of-phase Fenton catalyst, in examples 1, 2 and 3, under the condition of water quality fluctuation of hospital wastewater, the removal rates of COD, TOC, cephalexin and resistance genes are respectively about 57%, 42%, 100% and 100%, which are far higher than those of a control group, and the removal rates of COD, TOC and cephalexin are higher than those of commercial Fe/Al₂O₃A catalyst. Examples 3, 4 and 5 treatment of the same hospital wastewater quality, the red soil heterogeneous Fenton catalyst used was prepared under the same conditions, the removal rates of COD, TOC, cephalexin and resistance gene were stably higher than 55%, 40%, 100% and 100%, and the removal rates of COD, TOC and cephalexin were much higher than those of the control group, and the removal rates of COD, TOC and cephalexin were higher than those of commercial Fe/Al₂O₃A catalyst. Example 6 compared with example 1, the red soil heterogeneous Fenton catalyst preparation process has no pre-oxidation treatment, and the carbonization is carried out by directly introducing nitrogen into the carbonization converter, so that the hospital wastewater treatment effect is reduced, but the hospital wastewater treatment effect is still better than that of the commercial Fe/Al catalyst₂O₃A catalyst. Example 7 compared with example 1, the preparation process of the red soil heterogeneous Fenton catalyst is not modified by phosphoric acid, and the effect of treating hospital wastewater is greatly reduced and is lower than that of commercial Fe/Al₂O₃The catalyst has about 5% higher treatment effect than that without the catalyst. In general, the red soil heterogeneous Fenton catalyst prepared by the method has a good effect on treatment of refractory wastewater such as antibiotics and the like, such as hospital wastewater, is low in dissolution rate of active components of the catalyst, stable in property and long in service life, is subjected to pre-oxidation and carbonization treatment by using an autonomously designed carbonization converter, and is modified by phosphoric acid, so that the catalyst has an important effect on improvement of the performance of the catalyst.