CN116060004A

CN116060004A - Iron-carbon slow-release material and preparation method and application thereof

Info

Publication number: CN116060004A
Application number: CN202111277404.1A
Authority: CN
Inventors: 赵越; 蒋广安; 单广波; 王永剑
Original assignee: China Petroleum and Chemical Corp; Sinopec Dalian Research Institute of Petroleum and Petrochemicals
Current assignee: Sinopec Dalian Petrochemical Research Institute Co ltd; China Petroleum and Chemical Corp
Priority date: 2021-10-30
Filing date: 2021-10-30
Publication date: 2023-05-05

Abstract

The invention discloses an iron-carbon slow-release material, a preparation method and application thereof, wherein the iron-carbon slow-release material comprises an iron phase, silicon dioxide, carbon and inorganic refractory oxide; the iron phase is a dispersed particle of zero-valent iron and ferric oxide, the outer surface of the iron phase is coated with silicon dioxide, and the iron phase coated with the silicon dioxide is distributed in and/or on the pores of carbon and inorganic refractory oxide. The preparation method comprises (1) preparing iron-containing material; (2) preparing a siliceous material; (3) Mixing the iron-containing material, the silicon-containing material and the organic polymer, and finally introducing a carrier precursor to obtain the iron-carbon slow-release material after drying and roasting. The provided iron-carbon slow release material can realize the slow reaction of iron and carbon, and protect the iron from being rapidly oxidized, so that the method of in-situ catalytic oxidation can be combined to carry out long-term restoration on petroleum hydrocarbon pollutants.

Description

Iron-carbon slow-release material and preparation method and application thereof

Technical Field

The invention belongs to the technical field of catalytic materials, and particularly relates to a catalytic material for catalytic oxidation and a preparation method thereof.

Background

The advanced oxidation technology (AOPs) can utilize high-activity and strong-oxidability free radical species generated by activation of oxidant such as persulfate, percarbonate, hydrogen peroxide, ozone and the like, and can efficiently oxidize and degrade organic pollutants, and has the advantages of high reaction rate, strong oxidizing capability, almost no selectivity to organic matters, high mineralization rate and the like. In recent years, advanced oxidation technology has been rapidly developed in the field of organic pollutant wastewater treatment.

The iron-carbon material is a material for degrading organic pollutants, has the characteristic of micro-electrolysis reaction, and has been applied in many occasions. However, the conventional iron-carbon oxidation reaction has the defects that the iron-carbon reaction is severe, the iron mud is produced in a large amount, and the iron mud has better activity under the acidic condition, so that the application is limited.

Iron-carbon activated persulfate widens the application range of pH, but still has the problem of violent reaction and large amount of iron mud generation. Thus, two approaches of iron release and oxidant release are considered. Researchers use nano zero-valent iron and porous Fe ₂ O ₃ The particle activated persulfate is used for treating organic pollutants and can slowly release Fe ²⁺ Thereby controlling the activation speed of persulfate and ensuring the continuous and efficient degradation of pollutants of the system, but the problems of iron consumption and a large amount of iron mud generated by the electrolysis in iron and carbon cannot be solved as well as the slow release of oxidant. The generation of iron mud can block the water flow channel, and the replacement of the catalyst is difficult, so that the slow release material is required to have long-acting activity.

The slow release technology is firstly the drug research and development applied to the medical field, and is gradually applied to the environmental field to treat the pollution of soil and underground water after the current wide attention, and meanwhile, a good repairing effect is obtained, so that the slow release agent for repairing the pollution is derived. However, the slow release of the oxidizing agent is mostly performed, and the slow release of iron is less studied.

CN108675431a discloses a method for preparing a porous carbon coated magnetic nano molten iron treatment composite material by low-temperature pyrolysis of a Metal Organic Framework (MOF) and an application method thereof in water treatment. The invention firstly utilizes urea to preparePreparing graphite phase carbon nitride (g-C) ₃ N ₄ ) And then in-situ coupling with the iron-containing MOF, and finally carrying out low-temperature pyrolysis in an inert atmosphere to obtain the porous carbon coated magnetic nano molten iron treated composite material. The iron element in the composite material is mainly zero-valent iron and gamma-Fe ₂ O ₃ The form of (C) exists in the porous carbon, has excellent magnetic property and is easy to magnetically separate. However, the iron-carbon product prepared by the method has tight contact, is easy to cause iron ion loss, and is not suitable for iron-carbon reaction.

CN108690625a discloses a slow-release composite repairing agent for treating durable halogenated hydrocarbon in soil and a preparation method thereof. The preparation method comprises 1) preparing saturated black carbon of bacterial liquid; 2) Preparing a colloidal solution A containing locust bean gum and an organic carbon source; 3) Preparing a colloidal suspension B containing locust bean gum, an organic carbon source, nanoscale zero-valent metal and fungus liquid saturated black carbon; 4) Crosslinking reaction is carried out for 2-6 h; 5) And (3) carrying out delayed crosslinking reaction for 2-6 hours to obtain the slow-release composite repair agent for treating the durable halogenated hydrocarbon in the soil. The invention does not relate to iron-carbon reactions.

CN 201910067630.3A preparation and application of functional slow-release microcapsule for soil heavy metal treatment, discloses a preparation method of microcapsule under certain conditions, which takes microcrystalline cellulose as raw material, sodium alginate as adhesive and CaCl ₂ The method is characterized in that nano zero-valent iron (nZ VI) is used as a core material for preparing slow-release microcapsules for treating heavy metal pollution of soil. The invention uses the slow release agent to wrap the nanometer zero-valent iron, and the reaction rate is difficult to control.

CN201910373586.9 discloses a novel cherry-core-based biomass iron-carbon composite material. Cherry pit powder and anhydrous FeCl ₃ Uniformly mixing, calcining at high temperature under inert atmosphere, and Fe ³⁺ The material can be used for catalyzing and activating sodium persulfate to generate active free radicals to degrade endocrine disruptors bisphenol A by utilizing the oxidative activation cherry stone powder, and reducing the material into iron nano particles to be loaded on the cherry stone powder biomass activated carbon. The invention introduces iron in a conventional way and does not involve a slow release treatment

CN202010346235.1 discloses a process for producing nanoscale iron oxide, which comprises pre-activating nanoscale iron oxide, mixing with a hydrophobic agent, and performing a series of reactions to obtain nanoscale hydrophobic iron oxide. The nano iron oxide is firstly subjected to activation treatment, so that the contact effect of the nano iron oxide and the hydrophobic agent is better, and the hydrophobic capability of the nano iron oxide is improved. Can be used in the field of hydrophobic material preparation.

Disclosure of Invention

Aiming at the defects existing in the prior art, the invention mainly aims to provide the iron-carbon slow-release material, and the preparation method and the application thereof, and the provided iron-carbon slow-release material can realize the slow reaction of iron and carbon and protect the iron from being rapidly oxidized, so that the method of in-situ catalytic oxidation can be combined to carry out long-term restoration on petroleum hydrocarbon pollutants.

The first aspect of the invention provides an iron-carbon slow-release material, which comprises an iron phase, silicon dioxide, carbon and inorganic refractory oxide; the iron phase is a dispersed particle of zero-valent iron and ferric oxide, the outer surface of the iron phase is coated with silicon dioxide, and the iron phase coated with the silicon dioxide is distributed in and/or on the pores of carbon and inorganic refractory oxide.

Further, in the iron-carbon slow release material, the iron phase content is 5-35 wt%, preferably 10-30 wt%, based on the total weight of the iron-carbon slow release material; the silicon dioxide content is 0.5wt% to 4.0wt%, preferably 1.0wt% to 3.0wt%; the carbon content is 10 to 55wt percent, preferably 15 to 45wt percent; the inorganic refractory oxide content is 30wt% to 70wt%, preferably 35wt% to 60wt%.

Further, in the iron-carbon slow-release material, the pore diameter distribution of the iron-carbon slow-release material is as follows, wherein the pore diameter of the first-stage pore canal is smaller than 4nm, the most probable pore diameter is 2.5nm, the pore diameter of the second-stage pore canal is 4-9 nm, and the most probable pore diameter is 7.5nm; the pore diameter of the third stage pore canal is more than 9nm, preferably 9-20 nm, the most probable pore diameter is 13.5nm, and further, the ratio of peak intensity represented by Y-axis coordinates of the most probable pore diameters of the first stage pore canal, the second stage pore canal and the third stage pore canal is 2:1 to 4:1 to 8.

Further, in the iron-carbon slow-release material, the specific surface area of the iron-carbon slow-release material is 120-1200 m ² /g。

The second aspect of the invention provides a preparation method of an iron-carbon slow-release material, which comprises the following steps:

(1) Mixing ferric salt and a stabilizer, and adding an alkaline substance after uniform mixing to obtain an iron-containing material;

(2) Mixing the first silicon source, the second silicon source and the organic solvent uniformly to obtain a silicon-containing material;

(3) Mixing and reacting the iron-containing material, the silicon-containing material, formaldehyde and the auxiliary agent, and uniformly mixing to obtain a material A;

(4) Mixing a carbon source, an inorganic refractory oxide and a binder, uniformly mixing, and then forming, drying and roasting to obtain a carrier precursor;

(5) And (3) mixing the carrier precursor obtained in the step (4) with the material A obtained in the step (3) for reaction, and then drying and roasting to obtain the iron-carbon slow-release material.

Further, in the preparation method of the iron-carbon slow release material, the iron salt in the step (1) comprises trivalent iron salt and optional divalent iron salt, preferably trivalent iron salt; the ferric salt is at least one of ferric nitrate, ferric chloride, ferric citrate, ferric acetate and ferric sulfate, preferably ferric sulfate; the ferrous salt is at least one of ferrous chloride, ferrous acetate and ferrous sulfate, preferably ferrous sulfate.

In the preparation method of the iron-carbon slow-release material, the stabilizer in the step (1) is one or more of cetyltrimethylammonium chloride, cetyltrimethylammonium bromide, octadecyl trimethylammonium chloride, octadecyl trimethylammonium bromide, polyamide, polyethyleneimine and dimercaptosuccinic acid.

In the method for preparing the iron-carbon slow-release material, the alkaline substance in the step (1) is at least one of sodium hydroxide, potassium hydroxide, ammonia water, urea and sodium bicarbonate. The addition molar quantity of the alkaline substance is 0.8-1.5 times of that of the iron element.

Further, in the method for preparing the iron-carbon slow-release material, the first silicon source in the step (2) is at least one of silica sol, sodium silicate and silicic acid, preferably silica sol; the silica sol is further preferably alkaline silica sol, the pH value of the alkaline silica sol is 9-12, and the concentration of the silica sol is 10-40 wt%.

In the preparation method of the iron-carbon slow-release material, the second silicon source in the step (2) is organic silicon ester and/or organic siloxane, and the second silicon source can be one or more selected from tetraethyl silicate, methyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane, trimethylchlorosilane and octyltrimethoxysilane; tetraethyl silicate is preferred. The mass ratio of the second silicon source to the first silicon source is 1:2 to 6.

Further, in the preparation method of the iron-carbon slow-release material, the organic solvent in the step (2) is an alcohol compound and/or an ether compound, wherein the alcohol compound can be one or more selected from methanol, ethanol, n-propanol, n-butanol, n-pentanol, isopropanol, isobutanol and isoamyl alcohol, and ethanol is preferred; the ether compound can be selected from one or more of diethyl ether, petroleum ether, tetrahydrofuran and 1, 4-dioxane, and preferably tetrahydrofuran.

Further, in the preparation method of the integral slow-release iron-carbon catalytic material, in the step (3), the auxiliary agent is at least one of phenol, cresol, xylenol, resorcinol and urea, and the molar ratio of the auxiliary agent to formaldehyde is 1.2-2.5: 1.

further, in the preparation method of the integral slow-release iron-carbon catalytic material, the reaction condition in the step (3) is that the reaction temperature is 20-90 ℃.

In the preparation method of the integral slow-release iron-carbon catalytic material, the reaction condition in the step (3) is that the pH value of a reaction system is 9-12.

Further, in the preparation method of the iron-carbon slow-release material, the carbon source in the step (4) is one or more selected from biomass carbon, petroleum-based carbon, coal-based carbon and the like, and the carbon element content of the carbon source is not less than 60wt%; the carbon source can be one or more of active carbon, shell powder, wood powder, coconut shell powder, coal dust, coal tar, asphalt, organic polymer (polyethylene, polystyrene, polyvinyl chloride, polyacrylic acid, polyacrylonitrile, polymethyl methacrylate, polylactic acid, polycarbonate, phenolic resin, urea resin) and cellulose.

Further, in the preparation method of the iron-carbon slow release material, the inorganic refractory oxide in the step (4) may be one or more of alumina, molecular sieve and clay; further, the molecular sieve can be one or more selected from ZSM-5 molecular sieve, A-type molecular sieve, Y-type molecular sieve and beta-type molecular sieve; the clay can be silicon aluminum clay with granularity of 300-2000 meshes, and SiO in the components ₂ And Al ₂ O ₃ The sum of the mass accounts for more than 80 percent of the total mass of the silicon-aluminum clay, and the specific surface area is 5 to 500m ² /g。

Further, in the preparation method of the iron-carbon slow-release material, the binder in the step (4) is one or more of water, an inorganic binder and an organic binder, wherein the inorganic binder can be one or more selected from silica sol, alumina sol, aluminum dihydrogen phosphate and water glass, and the organic binder can be one or more selected from hydroxymethyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose, hydroxypropyl methyl cellulose, polyvinyl alcohol and polyethylene glycol.

Further, in the method for preparing the iron-carbon slow release material, the drying temperature in the step (4) is 50-120 ℃, preferably 60-110 ℃.

Further, in the method for preparing the iron-carbon slow release material, the roasting in the step (4) is performed under an anaerobic condition, for example, can be performed under an inert atmosphere such as nitrogen, helium, neon, argon and the like, and the roasting temperature is 500-900 ℃, preferably 600-700 ℃; the calcination time is 1 to 8 hours, preferably 2 to 4 hours.

In the preparation method of the iron-carbon slow-release material, the reaction temperature in the step (5) is 20-80 ℃, the reaction time is 2-24 h, and the pH value of a reaction system is preferably controlled to be 9-12.

Further, in the method for preparing the iron-carbon slow release material, the drying temperature in the step (5) is 50-120 ℃, preferably 60-110 ℃.

Further, in the method for preparing the iron-carbon slow release material, the roasting in the step (5) is performed under an anaerobic condition, for example, can be performed under an inert atmosphere such as nitrogen, helium, neon, argon and the like, and the roasting temperature is 500-900 ℃, preferably 600-700 ℃; the calcination time is 1 to 8 hours, preferably 2 to 4 hours.

The third aspect of the invention provides an iron-carbon slow-release material obtained by adopting the preparation method.

Further, in the iron-carbon slow-release material, the iron-carbon slow-release material comprises an iron phase, silicon dioxide, carbon and inorganic refractory oxide; the iron phase is a dispersed particle of zero-valent iron and ferric oxide, the outer surface of the iron phase is coated with silicon dioxide, and the iron phase coated with the silicon dioxide is distributed in and/or on the pores of carbon and inorganic refractory oxide.

Further, in the iron-carbon slow-release material, the pore diameter distribution of the iron-carbon slow-release material is as follows, wherein the pore diameter of the first-stage pore canal is smaller than 4nm, the most probable pore diameter is 2.5nm, the pore diameter of the second-stage pore canal is 4-9 nm, and the most probable pore diameter is 7.5nm; the pore diameter of the third stage pore canal is more than 9nm, preferably 9-20 nm, the most probable pore diameter is 13.5nm, and further, the ratio of the peak intensity (peak height) represented by the Y-axis coordinates of the most probable pore diameters of the first stage pore canal, the second stage pore canal and the third stage pore canal is 2:1 to 4:1 to 8.

The fourth aspect of the invention provides an application of the iron-carbon slow-release material in the treatment of petroleum hydrocarbon-containing wastewater.

Further, in the above application, the specific application process is that the petroleum hydrocarbon-containing wastewater is contacted with an oxidant, and the reaction is carried out in the presence of the iron-carbon slow-release material, and the purified water is obtained after the reaction.

Further, in the above application, the oxidizing agent is one or more of ozone, hydrogen peroxide, sodium persulfate and sodium percarbonate.

Further, in the above application, the petroleum hydrocarbon contained in the petroleum hydrocarbon-containing wastewater is mainly C4-C40 hydrocarbon, and the hydrocarbon is typically one or more of alkane, alkene, benzene series, halogenated hydrocarbon, etc.

Compared with the prior art, the iron-carbon slow-release material and the preparation method and application thereof have the following advantages:

the invention provides a composite catalyst formed by coating carrier materials such as iron particles and active carbon with silicon dioxide. Wherein, iron and silicon dioxide are mixed and crosslinked together in advance, and the preparation forms a hydrophobic silicon dioxide porous structure to restrict the iron active center, so that the invalid micro-electrolysis reaction of iron and carbon is weakened, the iron slowly participates in the reaction, and iron mud is not easy to generate. In the using process, the reaction core iron is highly dispersed in the carrier, so that the consumption of the iron does not influence the structural integrity of the carrier, and the mechanical strength of the material is not easy to change. The catalyst is matched with an oxidant to be used in a high-grade oxidation mode, has wider application range to pH and has wider application value.

Meanwhile, the carbon-containing composite material is used as a carrier, has strong adsorption capacity on organic pollutant components, and can adsorb pollutant molecules on the surface of a catalyst, so that the contact probability of active components and the pollutant molecules is increased, the local concentration is improved, the initial reaction rate is improved, and the catalytic oxidation reaction is facilitated. The content of active carbon in the carbon-containing composite carrier is controlled at a reasonable proportion, and the unique contact mode with iron particles also obviously reduces the invalid reaction of iron-carbon micro-electrolysis. The carbon-containing composite carrier has a porous structure, can adsorb iron ions generated by iron-carbon reaction, forms a catalytic active center in situ, and continuously maintains good catalytic oxidation activity.

Detailed Description

The preparation method of the present invention will be further described with reference to specific examples, but the scope of the present invention is not limited to the examples.

The specific surface area and average pore size referred to in the examples and comparative examples of the present invention were measured using a nitrogen physical adsorption instrument. The ratio of the most probable pore size to the Y-axis value on the pore size distribution curve is noted as the peak intensity ratio. The iron ion analysis method is a microwave digestion/inductively coupled plasma mass spectrometry. The silica content referred to in the present invention is the mass of silica combined with iron at the time of addition, excluding the mass of silica introduced into the inorganic refractory oxide and binder.

All percentages, parts, ratios, etc. referred to in this specification are by weight and pressure is gauge unless explicitly indicated.

Throughout the specification and claims, unless explicitly stated otherwise, the term "comprise" or variations thereof such as "comprises" or "comprising", etc. will be understood to include the stated element or component without excluding other elements or other components.

Spatially relative terms, such as "below," "beneath," "lower," "above," "upper," and the like, may be used herein for ease of description to describe one element's or feature's relationship to another element's or feature.

The terms "first," "second," and the like herein are used for distinguishing between two different elements or regions and are not intended to limit a particular position or relative relationship. In other words, in some embodiments, the terms "first," "second," etc. may also be interchanged with one another.

In this document, all numerical values of a parameter (e.g., quantity or condition) are to be understood as being modified in all instances by the term "about," whether or not "about" actually occurs before the numerical value.

Any two or more embodiments of the invention may be combined in any desired manner within the context of this specification, and the resulting solution is part of the original disclosure of this specification, while still falling within the scope of the invention.

Example 1

241g of ferric nitrate is weighed to prepare ferric salt solution, 2.8g of cetyltrimethylammonium bromide is added, the mixture is stirred uniformly, and 60.7g of ammonia water is added to form colloidal solution A. 13.3g of 30wt% silica sol, 5.6g of tetraethyl silicate and 25g of ethanol are weighed, mixed evenly, added with 1.8g of phenol, at the moment, poured into solution A, the pH value is regulated to 9.5 by ammonia water, 1.2g of formaldehyde is added dropwise, and stirring is continued for 30min to form solution B. 290g of active carbon, 186g of silicon aluminum clay and 22.4g of water glass are uniformly mixed, extruded and molded according to a conventional method, dried at 110 ℃ for 8 hours and baked at 600 ℃ for 6 hours in an isolated manner to obtain the carrier. Adding the carrier into the solution B, heating to 65 ℃ in a water bath, reacting for 6 hours, taking out the carrier, and evaporating the carrier by rotating. And (3) roasting the dried material at 550 ℃ for 3 hours while isolating oxygen, thus obtaining the iron-carbon slow release material A1. Specific surface area of material 523m ² And/g, the ratio of the most probable pore size peak intensities of the first-stage pore canal, the second-stage pore canal and the third-stage pore canal is 2:1.3:2.6.

example 2

245g of ferric citrate is weighed to prepare ferric salt solution, 1.2g of polyacetylimine is added, and the mixture is stirred uniformly. 40g of sodium hydroxide was then added to form a colloidal solution A. 5.1g of sodium silicate, 3.8g of methyltriethoxysilane and 40g of diethyl ether are weighed, mixed evenly, added with 1.5g of urea, at the moment, poured into solution A, the pH value is regulated to 10 by sodium hydroxide, 1.0g of formaldehyde is added dropwise, and stirring is continued for 10min to form solution B. Mixing 56g of active carbon, 104g of silicon aluminum clay, 50g of 4A molecular sieve and 20g of aluminum dihydrogen phosphate colloid uniformly, extruding and molding by a conventional method, drying at 100 ℃ for 12h, and roasting at 700 ℃ for 2h while isolating oxygen to obtain the carrier. The carrier is immersed in the solution B, reacted for 6 hours at room temperature and rotary evaporated to dryness. And (3) roasting the dried material at 500 ℃ for 2 hours in an oxygen-isolated manner to obtain the iron-carbon slow-release material A2. Specific surface area 387m of material ² And/g, the ratio of the most probable pore size peak intensities of the first-stage pore canal, the second-stage pore canal and the third-stage pore canal is 2:3.3:3.6.

example 3

152g of ferrous sulfate is weighed to prepare ferric salt solution, and 2.0g of ten-component is addedOctaalkyl trimethyl ammonium bromide is stirred uniformly. 80g of sodium bicarbonate was added to form a colloidal solution A. Weighing 5g of 40% alkaline silica sol, mixing 2.8g of tetraethyl methylsilicate with 40g of methanol, uniformly stirring, adding 2.0g of resorcinol, pouring the solution A at the moment, adjusting the pH to 9.5 by potassium hydroxide, dropwise adding 0.8g of formaldehyde, and continuously stirring for 20min to form a solution B. Uniformly mixing 74.6g of active carbon, 87.6g of alumina and 5.6g of carboxymethyl cellulose, extruding and molding by a conventional method, drying at 95 ℃ for 7h, and roasting at 680 ℃ for 6h under the protection of argon gas to obtain the carrier. Adding the carrier into the solution B, heating to 62 ℃ in a water bath, reacting for 6 hours, taking out the carrier, and evaporating the carrier by rotating. And (3) roasting the dried material at 600 ℃ for 5 hours while isolating oxygen, thus obtaining the iron-carbon slow release material A3. Specific surface area of material 611m ² And/g, the ratio of the most probable pore size peak intensities of the first-stage pore canal, the second-stage pore canal and the third-stage pore canal is 2:3.5:5.5.

example 4

400g of ferric sulfate is weighed to prepare ferric salt solution, 1.6g of polyamide is added, and the mixture is stirred uniformly. 60g of urea was then added to form a colloidal solution A. 4.5g of silicic acid, 1.3g of trimethylchlorosilane and 25g of tetrahydrofuran are weighed and mixed, 2.4g of phenol is added after uniform stirring, the pH is regulated to 9.5 by potassium hydroxide, 1.6g of formaldehyde is added dropwise, and stirring is continued for 20min to form a solution B. Uniformly mixing 286g of active carbon, 240g of white carbon black and 36.4g of water glass, extruding and molding by a conventional method, drying at 100 ℃ for 12h, and roasting at 700 ℃ for 2h under helium protection to obtain the carrier. Mixing the solution A and the solution B, stirring for 15min, adding the carrier, heating to 75 ℃ in a water bath, reacting for 5h, taking out the carrier, and rotationally evaporating to dryness. Roasting the dried material for 6 hours under nitrogen protection at 680 ℃ to obtain the iron-carbon slow release material A4. Specific surface area of material 658m ² And/g, the ratio of the most probable pore size peak intensities of the first-stage pore canal, the second-stage pore canal and the third-stage pore canal is 2:1.2:1.8.

example 5

95.5g of ferric acetate and 63g of ferrous chloride are weighed and mixed to prepare ferric salt solution, and 2.5g of cetyltrimethylammonium chloride is added and stirred uniformly. 60g of potassium hydroxide was added to form a colloidal solution A. Weighing 19.3g of 20wt% alkaline silica sol, mixing 2.4g of tetraethyl silicate and 30g of ethanol, adding 2.3g of urea after uniformly stirring, and regulating the PH to be 1 by using ammonia water0, 1.7g of formaldehyde is added dropwise, and stirring is continued for 20min to form a solution B. Uniformly mixing 28.4g of active carbon, 78.8g of silicon-aluminum clay and 13.3g of hydroxypropyl methyl cellulose, extruding and molding by a conventional method, drying at 90 ℃ for 12h, and roasting at 650 ℃ for 6h under nitrogen protection to obtain the carrier. Mixing the solution A and the solution B, stirring for 20min, adding the carrier, heating to 55 ℃ in a water bath, reacting for 6h, taking out the carrier, and rotationally evaporating to dryness. Roasting the dried material for 6 hours at 720 ℃ under nitrogen protection to obtain the iron-carbon slow release material A5. Specific surface area of material 523m ² And/g, the ratio of the most probable pore size peak intensities of the first-stage pore canal, the second-stage pore canal and the third-stage pore canal is 2:3.6:6.2.

example 6

200mL of iron-carbon slow-release material A1 is filled in a cylindrical reaction tube, and under the action of 250mg/L of sodium persulfate, the continuous reaction is carried out to treat the gasoline simulated petroleum hydrocarbon wastewater with COD of 150 mg/L, the iron ion concentration in the effluent is 26 mg/L, and the COD removal rate is 93.1%.

Example 7

1g of iron-carbon slow-release material A2 is measured and filled in a sealed bottle, 100g of petrol-simulated petroleum hydrocarbon wastewater with initial COD of 150 mg/L is poured, 0.2g of sodium persulfate is added, continuous oscillation is carried out for 180min at 25 ℃ in a constant-temperature oscillator, the concentration of iron ions in a water sample after reaction is detected to be 55 mg/L, and the COD removal rate is 95.3%.

Example 8

200mL of iron-carbon slow-release material A3 is filled in a cylindrical reaction tube, diesel oil simulated petroleum hydrocarbon wastewater with COD of 120 mg/L is continuously reacted under the action of 125mg/L of sodium persulfate, the iron ion concentration in the effluent is 21 mg/L, and the COD removal rate is 92.5%.

Example 9

0.5g of iron-carbon slow-release material A4 is measured and filled in a sealed bottle, 100g of petrol-simulated petroleum hydrocarbon wastewater with initial COD of 100 mg/L is poured, 0.2g of sodium persulfate is added, continuous oscillation is carried out for 120min at 35 ℃ in a constant-temperature oscillator, the concentration of iron ions in a water sample after reaction is detected to be 28 mg/L, and the COD removal rate is 94.2%.

Example 10

500mL of iron-carbon slow-release material A5 is filled in a cylindrical reaction tube, gasoline simulated petroleum hydrocarbon wastewater with COD of 120 mg/L is continuously reacted under the action of 300mg/L of sodium persulfate, the concentration of iron ions in effluent water is 59 mg/L, and the COD removal rate is 96.1%.

Comparative example 1

386.4g of active carbon, 140g of silicon aluminum clay and 22.4g of water glass are uniformly mixed, extruded and molded according to a conventional method, dried at 110 ℃ for 8 hours and baked at 600 ℃ for 6 hours in an isolated manner to obtain the carrier. 241g of ferric nitrate is weighed to prepare ferric salt solution, and the carrier is added into the solution for dipping and rotary evaporation to dryness. And (3) roasting the dried material at 550 ℃ for 3 hours while isolating oxygen, thus obtaining the catalytic material B1.

Comparative example 2

45g and 25g of scrap iron and active carbon are respectively weighed, mixed and filled in a cylindrical reaction tube, and under the action of 300mg/L of sodium persulfate, the continuous reaction is carried out to treat the gasoline simulated petroleum hydrocarbon wastewater with COD of 200 mg/L, obvious yellow precipitation exists in the effluent, and the contact part of the scrap iron and the active carbon is hardened quickly. The concentration of iron ions is 7839 mg/L, and the COD removal rate after settling the iron ions is 88.1%.

Comparative example 3

Example 6 was repeated, the iron-carbon slow-release material A1 was changed to the catalytic material B1, and the removal rate of COD was 79.2% in the effluent having an iron ion concentration of 1426 mg/L.

Comparative example 4

The conventional iron-carbon reaction is adopted, 40g, 20g and 35g of scrap iron, active carbon and inert porcelain balls are respectively weighed, mixed and filled in a cylindrical reaction tube, toluene with COD of 160 mg/L is introduced to simulate petroleum hydrocarbon wastewater, obvious yellow precipitation exists in effluent, and the contact part of the scrap iron and the active carbon is quickly hardened. The concentration of iron ions 6621 mg/L and the COD removal rate after settling the iron ions is 81.5%.

Comparative example 5

50g of active carbon and 50g of scrap iron are weighed, mixed and filled in a cylindrical reaction tube, and 100 mg/L of sodium persulfate is added into petroleum hydrocarbon-containing underground water of a certain gas station with the COD average value of 140 mg/L to carry out continuous reaction, wherein obvious yellow precipitation exists in the effluent, and the contact part of the scrap iron and the active carbon is hardened quickly. The concentration of iron ions 7351 mg/L and the COD removal rate after settling the iron ions was 87.2%.

Claims

1. An iron-carbon slow release material comprises an iron phase, silicon dioxide, carbon and inorganic refractory oxide; the iron phase is a dispersed particle of zero-valent iron and ferric oxide, the outer surface of the iron phase is coated with silicon dioxide, and the iron phase coated with the silicon dioxide is distributed in and/or on the pores of carbon and inorganic refractory oxide.

2. The iron-carbon slow release material according to claim 1, wherein the iron phase content is 5wt% to 35wt%, preferably 10wt% to 30wt%, based on the total weight of the iron-carbon slow release material; the silicon dioxide content is 0.5wt% to 4.0wt%, preferably 1.0wt% to 3.0wt%; the carbon content is 10 to 55wt percent, preferably 15 to 45wt percent; the inorganic refractory oxide content is 30wt% to 70wt%, preferably 35wt% to 60wt%.

3. The iron-carbon slow release material according to claim 1, wherein the pore size distribution of the iron-carbon slow release material is as follows, wherein the pore diameter of the first-stage pore canal is less than 4nm, the most probable pore diameter is 2.5nm, the pore diameter of the second-stage pore canal is 4-9 nm, and the most probable pore diameter is 7.5nm; the pore diameter of the third-stage pore canal is more than 9nm, preferably 9-20 nm, and the most probable pore diameter is 13.5nm.

4. The iron-carbon slow release material according to claim 1, wherein the ratio of peak intensities represented by Y-axis coordinates of the most probable pore diameters of the primary pore passage, the secondary pore passage and the tertiary pore passage is 2:1 to 4:1 to 8.

5. The iron-carbon slow release material according to claim 1, wherein the specific surface area of the iron-carbon slow release material is 120-1200 m ² /g。

6. The preparation method of the iron-carbon slow-release material comprises the following steps:

(3) Mixing and reacting an iron-containing material, a silicon-containing material, formaldehyde and an auxiliary agent, and uniformly mixing to obtain a material A, wherein the auxiliary agent is at least one of phenol, cresol, xylenol, resorcinol and urea;

7. The method for producing an iron-carbon slow release material according to claim 6, wherein the iron salt in step (1) comprises a trivalent iron salt and optionally a divalent iron salt, preferably a trivalent iron salt; the ferric salt is at least one of ferric nitrate, ferric chloride, ferric citrate, ferric acetate and ferric sulfate, preferably ferric sulfate; the ferrous salt is at least one of ferrous chloride, ferrous acetate and ferrous sulfate, preferably ferrous sulfate.

8. The method for preparing an iron-carbon slow-release material according to claim 6, wherein the stabilizer in the step (1) is one or more of cetyltrimethylammonium chloride, cetyltrimethylammonium bromide, octadecyl trimethylammonium chloride, octadecyl trimethylammonium bromide, polyamide, polyethyleneimine and dimercaptosuccinic acid.

9. The method for producing an iron-carbon slow-release material according to claim 6, wherein the alkaline substance in the step (1) is at least one of sodium hydroxide, potassium hydroxide, ammonia, urea and sodium bicarbonate.

10. The method for producing an iron-carbon slow-release material according to claim 6, wherein the alkaline substance is added in a molar amount of 0.8 to 1.5 times that of the iron element.

11. The method for producing an iron-carbon slow release material according to claim 6, wherein the first silicon source in the step (2) is at least one of silica sol, sodium silicate, silicic acid, preferably silica sol; the silica sol is further preferably alkaline silica sol, the pH value of the alkaline silica sol is 9-12, and the concentration of the silica sol is 10-40 wt%.

12. The method for producing an iron-carbon slow-release material according to claim 6, wherein the second silicon source in the step (2) is an organic silicon ester and/or an organic siloxane, and further specifically the second silicon source is one or more selected from the group consisting of tetraethyl silicate, methyl orthosilicate, methyltrimethoxysilane, methyltriethoxysilane, trimethylchlorosilane, and octyltrimethoxysilane; preferably tetraethyl silicate; the mass ratio of the second silicon source to the first silicon source is 1:2 to 6.

13. The method for preparing an iron-carbon slow-release material according to claim 6, wherein the organic solvent in the step (2) is an alcohol compound and/or an ether compound, and the alcohol compound can be one or more selected from methanol, ethanol, n-propanol, n-butanol, n-pentanol, isopropanol, isobutanol and isoamyl alcohol, preferably ethanol; the ether compound is selected from one or more of diethyl ether, petroleum ether, tetrahydrofuran and 1, 4-dioxane, and preferably tetrahydrofuran.

14. The method for producing an iron-carbon slow-release material according to claim 6, wherein the molar ratio of the auxiliary agent to formaldehyde in the step (3) is 1.2 to 2.5:1.

15. the method for producing an iron-carbon slow-release material according to claim 6, wherein the carbon source in the step (4) is one or more selected from biomass charcoal, petroleum-based charcoal, coal-based charcoal, etc., and the carbon element content of the carbon source is not less than 60wt%.

16. The method for producing an iron-carbon slow-release material according to claim 6, wherein the carbon source is one or more of activated carbon, nut shell powder, wood powder, coconut shell powder, coal dust, coal tar, pitch, a polymer organic polymer having a polymerization degree of more than 3000, and cellulose.

17. The method for producing an iron-carbon slow-release material according to claim 6, wherein the inorganic refractory oxide in the step (4) is one or more of alumina, a molecular sieve and clay.

18. The method for producing an iron-carbon slow-release material according to claim 6, wherein the binder in the step (4) is one or more of water, an inorganic binder and an organic binder, the inorganic binder is one or more selected from silica sol, alumina sol, aluminum dihydrogen phosphate and water glass, and the organic binder is one or more selected from hydroxymethyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose, hydroxypropyl methyl cellulose, polyvinyl alcohol and polyethylene glycol.

19. The method for producing an iron-carbon slow release material according to claim 6, wherein the drying temperature in step (4) and step (5) is 50 to 120 ℃, preferably 60 to 110 ℃.

20. The method for producing an iron-carbon slow release material according to claim 6, wherein the firing in step (4) and step (5) is performed under an oxygen-free condition at a firing temperature of 500 to 900 ℃, preferably 600 to 700 ℃.

21. The method for producing an iron-carbon slow release material according to claim 6, wherein the reaction temperature in the step (5) is 20 to 80 ℃, and the pH value of the reaction system is controlled to 9 to 12.

22. An iron-carbon slow release material obtained by the preparation method of any one of claims 7 to 21.

23. Use of an iron-carbon slow-release material according to any one of claims 1-6 and 22 in the treatment of petroleum hydrocarbon-containing wastewater, wherein the petroleum hydrocarbon-containing wastewater is contacted with an oxidizing agent and reacted in the presence of the iron-carbon slow-release material to obtain purified water after the reaction.

24. The use according to claim 23, wherein the oxidizing agent is one or more of ozone, hydrogen peroxide, sodium persulfate, sodium percarbonate.