Preparation method of zeolite-magnetic iron oxide and application of zeolite-magnetic iron oxide in catalyzing sodium percarbonate to repair petroleum hydrocarbon polluted soil

Abstract

The invention belongs to the technical field of environmental rock soil, and particularly relates to a preparation method of zeolite-magnetic iron oxide and application of the zeolite-magnetic iron oxide in catalyzing sodium percarbonate to repair petroleum hydrocarbon polluted soil. The specific method comprises the following steps: carrying out alkali treatment on zeolite, and then carrying out heat treatment to obtain alkali-heat combined modified zeolite; extracting an iron element in the iron-containing by-product with acid and preparing ferric hydroxide colloid; and uniformly mixing the alkali-heat combined modified zeolite with the ferric hydroxide colloid, carrying out solid-liquid separation, and then carrying out heat treatment and hydrogen reduction treatment to obtain the zeolite-magnetic iron oxide, the application specifically comprises the following steps: uniformly mixing sodium percarbonate, tween-80, silica sol and water to prepare a turbid solution A; uniformly mixing zeolite-magnetic iron oxide, organic acid, silica sol and water to prepare a turbid solution B; and uniformly mixing the turbid liquid B with the petroleum hydrocarbon polluted soil, then adding the turbid liquid A, uniformly mixing, and maintaining for 12-15 days to finish the remediation.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental rock and soil, and in particular relates to a preparation method of zeolite-magnetic iron oxide and application of the zeolite-magnetic iron oxide in catalyzing sodium percarbonate to repair soil contaminated by petroleum hydrocarbons. Background Art

[0002] In recent years, with the continuous advancement of industrialization, the problem of soil contamination by petroleum hydrocarbons has become increasingly serious, posing a serious threat to the ecological environment and human health. Therefore, the development of efficient, economical and environmentally friendly soil remediation technology has become one of the hot topics in environmental science research.

[0003] First, at home and abroad, research on soil remediation using zeolites and iron-containing byproducts produced during metal smelting has made some progress. Zeolite, as a natural mineral, has strong adsorption capacity and huge surface area, and can effectively adsorb petroleum hydrocarbon pollutants. The iron-containing byproducts produced during metal smelting are rich in iron and have good catalytic properties. In foreign research, there are relatively rich studies on the use of zeolites and iron-based materials to repair petroleum hydrocarbon-contaminated soil. For example, some research teams have achieved good remediation effects by modifying zeolites to improve their adsorption capacity and catalytic activity. In China, the research on environmental remediation using iron in iron-containing byproducts produced during metal smelting has also gradually increased. Related studies have shown that water and soil treated with iron-containing byproducts have achieved significant purification effects.

[0004] However, despite a certain research foundation, there are still some technical difficulties in the method of using zeolite and iron-containing byproducts to co-heat to construct zeolite-magnetic iron oxide to catalyze sodium percarbonate to repair petroleum hydrocarbon contaminated soil. The first is the problem of material preparation. How to efficiently extract the iron element in the iron-containing byproduct and make it form a stable magnetic iron oxide carrier with zeolite during the co-heating process is the key to realizing this method. The second is the optimization of process parameters. The reaction conditions of the co-heating method, such as temperature, time, reaction atmosphere, etc., will affect the performance of the final product and need to be optimized through a large number of experiments. In addition, the catalytic activity and stability of zeolite loaded with magnetic iron oxide in the process of catalyzing sodium percarbonate are also one of the technical difficulties, and its reaction mechanism and catalytic performance need to be studied in depth.

[0005] In the catalytic sodium percarbonate remediation of petroleum hydrocarbon contaminated soil, domestic and foreign research mainly focuses on the selection of sodium percarbonate activators and its catalytic performance. Sodium percarbonate is a commonly used oxidant with strong oxidizing properties and can effectively degrade petroleum hydrocarbon pollutants. However, its catalytic activity in soil is low, and catalysts are needed to improve its oxidation efficiency. Studies have shown that porous materials loaded with metal oxides, such as zeolites loaded with iron oxides, have good catalytic activity. However, how to improve the catalytic performance of zeolites loaded with magnetic iron oxides, especially to maintain their stability and durability in complex soil environments, remains an urgent problem to be solved. Future research should focus on how to improve the catalytic activity and stability of materials, optimize the reaction conditions of the co-thermal method, and explore its application effect in actual soil environments. Through these studies, the practical application of this method can be further promoted, providing new ideas and technical support for the efficient remediation of petroleum hydrocarbon contaminated soil.

[0006] In summary, the method of constructing zeolite-magnetic iron oxide based on zeolite and iron-containing by-products and its catalytic sodium percarbonate to repair petroleum hydrocarbon contaminated soil has a certain research foundation at home and abroad, but there are still technical difficulties such as material preparation, process parameter optimization and catalytic performance improvement.

[0007] Therefore, it is of great significance to construct a new zeolite-magnetic iron oxide and explore its preparation method and application. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a method for constructing zeolite-magnetic iron oxide and its catalytic sodium percarbonate repairing petroleum hydrocarbon contaminated soil based on zeolite and iron-containing byproducts by co-heating method, in view of the limited adsorption capacity of existing zeolites, poor loading effect, low content of loaded target substances, weak catalytic ability after synthesis, etc. The zeolite is modified multiple times to improve the adsorption characteristics of the zeolite and the adsorption and catalytic performance of the synthesized zeolite-magnetic iron oxide.

[0009] In order to solve the above technical problems, the present invention discloses a method for preparing zeolite-magnetic iron oxide, which comprises the following specific steps:

[0010] S1. treating the zeolite with alkali and then heat treating it to obtain an alkali-heat combined modified zeolite;

[0011] S2. extracting the iron in the iron-containing byproduct with acid and preparing iron hydroxide colloid;

[0012] S3. The alkali-heat combined modified zeolite and the iron hydroxide colloid are uniformly mixed, and after solid-liquid separation, heat treatment and hydrogen reduction treatment are performed to obtain the zeolite-magnetic iron oxide.

[0013] Among them, in S1, the specific process of the alkali treatment is: putting the zeolite into a sodium hydroxide solution, heating and stirring at 80-120°C for 20-25 hours, soaking for 70-75 hours after cooling, and then washing after solid-liquid separation; wherein the mass volume ratio of the zeolite and sodium hydroxide is (50-70):1; the concentration of the sodium hydroxide solution is 0.1-0.3 mol / L.

[0014] Among them, in S1, the specific conditions of the heat treatment are: the temperature is controlled at 300-600°C, and the heating time is controlled at 8-12h;

[0015] Preferably, in S1, the specific conditions of the heat treatment are: the temperature is controlled at 600° C., and the heating time is controlled at 12 h.

[0016] The specific steps in S2 are: adding the iron-containing byproduct to concentrated sulfuric acid at a mass volume ratio of 1: (3-9), stirring for 24 hours, adding deionized water 4 times the volume of concentrated sulfuric acid to the filtrate after solid-liquid separation to obtain an iron-containing filtrate, adding sodium hydroxide solution to the iron-containing filtrate until the pH of the filtrate reaches 7, thereby obtaining iron hydroxide colloid; wherein the iron-containing byproduct is scrap iron and / or steel slag; and the concentration of the sodium hydroxide solution is 0.1-0.3 mol / L;

[0017] Preferably, the mass volume ratio of the iron-containing byproduct to the concentrated sulfuric acid is 1:9.

[0018] The specific steps in S3 are: uniformly mixing the alkali-heat combined modified zeolite and the iron hydroxide colloid in a mass volume ratio of (0.5-3):10, continuously stirring for 24 hours, washing the solid after solid-liquid separation, and then heating the solid at 600°C for 8 hours, and then heating the heated solid at 600-1000°C for 4 hours in a hydrogen atmosphere, wherein the flow rate of the hydrogen is 50-500 ml / min;

[0019] Preferably, the specific steps in S3 are: uniformly mixing the alkali-heat combined modified zeolite and the iron hydroxide colloid in a mass volume ratio of 2:10, continuously stirring for 24 hours, washing the solid after solid-liquid separation, and then heating the solid at 600°C for 8 hours, and then heating the heated solid at 900°C for 4 hours in a hydrogen atmosphere, wherein the flow rate of the hydrogen is 300 ml / min.

[0020] Specifically, in some embodiments of the present invention, the zeolite-magnetic iron oxide prepared by the above method is mixed with sodium percarbonate and used to repair petroleum hydrocarbon contaminated soil, and the efficiency of repairing petroleum hydrocarbon contaminated soil is explored, thereby verifying the application prospects of zeolite-magnetic iron oxide in the field of catalyzing sodium percarbonate to repair petroleum hydrocarbon contaminated soil.

[0021] The specific steps of the application are:

[0022] S11. Sodium percarbonate, Tween-80, silica sol and water were mixed to prepare a turbid solution A;

[0023] S22. The zeolite-magnetic iron oxide, organic acid, silica sol and water are uniformly mixed to prepare a turbid solution B;

[0024] S33. Mix turbid liquid B and petroleum hydrocarbon contaminated soil evenly, then add turbid liquid A and mix evenly. Curing for 12 to 15 days to complete the restoration.

[0025] Wherein, in the turbid liquid A, the mass ratio of sodium percarbonate, Tween-80 and silica sol is (1-3): (0.5-1.5): (0.1-0.2), and the ratio of the volume of added water to the total mass of sodium percarbonate, Tween-80 and silica sol is 5:1;

[0026] Preferably, in the turbid liquid A, the mass ratio of sodium percarbonate, Tween-80 and silica sol is 2:1.5:0.1.

[0027] The mass ratio of the sodium percarbonate to the zeolite-magnetic iron oxide material is (1-5): (0.5-4); in the turbid solution B, the mass ratio of the zeolite-magnetic iron oxide, the organic acid, and the silica sol is (1-1.5): (1-3): (0.1-0.3), and the ratio of the volume of the added water to the total mass of the zeolite-magnetic iron oxide material, the lactic acid, and the silica sol is 3:1;

[0028] Preferably, the organic acid comprises lactic acid and citric acid;

[0029] Preferably, the mass ratio of the sodium percarbonate to the zeolite-magnetic iron oxide material is 5:1;

[0030] Preferably, the mass ratio of the zeolite-magnetic iron oxide, organic acid and silica sol is 1.5:3:0.1.

[0031] Among them, in S33, the petroleum hydrocarbon contaminated soil needs to be pretreated, and the specific steps of the pretreatment are to remove stones and roots in the soil and air-dry it, and then crush it and pass it through a 2mm sieve.

[0032] Beneficial effects: 1. The present invention uses waste iron and steel slag as raw materials to prepare magnetic iron oxide and composites it with zeolite. The prepared zeolite-magnetic iron oxide has good catalytic activity and stability;

[0033] 2. The present invention uses silica sol to load zeolite-magnetic iron oxide to achieve secondary loading of iron oxide, thereby ensuring the stability and sustained release characteristics of iron oxide;

[0034] 3. Replace traditional inorganic acid substances with organic acids to maintain the acidic repair environment. At the same time, organic acids can release trace elements in the soil itself and serve as a carbon source, which has a positive effect on the secondary utilization of the soil.

[0035] 4. The present invention further studies the conditions for the combined use of zeolite-magnetic iron oxide and sodium percarbonate, providing a direction for better achieving efficient remediation of petroleum hydrocarbon contaminated soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0037] Figure 1 It is a technical flow chart of the present invention;

[0038] Figure 2 This is a graph showing the influence of heat treatment temperature and time on the catalytic performance of zeolite-magnetic iron oxide in the alkali-heat combined modified zeolite in the embodiment of the present invention;

[0039] Figure 3 This is a graph showing the effect of the mass of scrap iron and the volume ratio of concentrated sulfuric acid on the catalytic performance of zeolite-magnetic iron oxide in an embodiment of the present invention;

[0040] Figure 4 This is a graph showing the influence of the mass of the zeolite modified by alkali-heat combined with the volume ratio of the ferric hydroxide colloidal solution on the catalytic performance of the zeolite-magnetic iron oxide in the embodiment of the present invention;

[0041] Figure 5 This is a graph showing the effect of hydrogen flow rate on the catalytic performance of zeolite-magnetic iron oxide in an embodiment of the present invention;

[0042] Figure 6 This is a graph showing the effect of heat treatment temperature on the catalytic performance of zeolite-magnetic iron oxide in the hydrogen reduction process in an embodiment of the present invention;

[0043] Figure 7 This is a graph showing the effect of the mass ratio of sodium percarbonate, Tween-80 and silica sol on the degradation effect of petroleum hydrocarbons in an embodiment of the present invention;

[0044] Figure 8 This is a graph showing the effect of the mass ratio of sodium percarbonate to zeolite-magnetic iron oxide on the degradation effect of petroleum hydrocarbons in an embodiment of the present invention;

[0045] Fig. 9 This is a graph showing the influence of the mass ratio of zeolite-magnetic iron oxide material, lactic acid, and silica sol on the degradation effect of petroleum hydrocarbons in an embodiment of the present invention. DETAILED DESCRIPTION

[0046] The experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are commercially available unless otherwise specified.

[0047] Example 1: Effect of heat treatment temperature and time in alkali-heat combined modified zeolite on the catalytic performance of zeolite-magnetic iron oxide

[0048] The zeolite was put into 0.2mol / L sodium hydroxide solution, the mass ratio of zeolite to sodium hydroxide solution (g / L) was 60:1, heated and stirred at 100°C for 24h, cooled to room temperature, soaked for 72h, and solid-liquid separation was performed. The solid obtained by solid-liquid separation was washed with deionized water and placed in a muffle furnace for heat treatment. The heating temperature was controlled at 300°C, 400°C, 500°C and 600°C, and the heating time was controlled at 8h, 10h and 12h, respectively, to obtain alkali-heat combined modified zeolite.

[0049] Put the scrap iron into concentrated sulfuric acid, the mass ratio of scrap iron to concentrated sulfuric acid (g / mL) is 1:3, and stir continuously for 24 hours. The obtained mixture is separated into solid and liquid, and the obtained filtrate is retained and deionized water is added to obtain an iron-containing filtrate, and the amount of deionized water is 4 times the volume of concentrated sulfuric acid. Add 0.2 mol / L sodium hydroxide solution to the iron-containing filtrate, adjust the solution pH to 7, and form a stable iron hydroxide colloid.

[0050] The alkali-heat modified zeolite was added to the iron hydroxide colloid, and the volume ratio (g / mL) of the alkali-heat modified zeolite mass to the iron hydroxide colloid solution was 0.5:10. The mixture was stirred for 24 hours, and then the solid-liquid separation was performed, and the solid matter was washed with deionized water. The obtained solid matter was placed in a muffle furnace and heated for 8 hours at a heating temperature of 600°C. The heated solid matter was placed in a hydrogen atmosphere and heated for 4 hours at a hydrogen flow rate of 50 ml / min and a heating temperature of 600°C to obtain zeolite-magnetic iron oxide.

[0051] Take petroleum hydrocarbon contaminated soil for pretreatment. Sodium percarbonate, Tween-80, silica sol and water were mixed and stirred, the mass ratio of sodium percarbonate, Tween-80 and silica sol was 1:0.5:0.1, and the ratio of the volume of water added to the total mass of sodium percarbonate, Tween-80 and silica sol (mL / g) was 5:1, and turbid liquid A was prepared; zeolite-magnetic iron oxide material, lactic acid, silica sol (the mass concentration of silica sol used was 30%) and water were mixed and stirred, wherein the mass ratio of sodium percarbonate to zeolite-magnetic iron oxide material was 1:0.5, the mass ratio of zeolite-magnetic iron oxide material, lactic acid and silica sol was 1:1:0.1, and the ratio of the volume of water added to the total mass of zeolite-magnetic iron oxide material, lactic acid and silica sol (mL / g) was 3:1, and turbid liquid B was prepared. Turbid liquid B was poured into the petroleum hydrocarbon contaminated soil, pre-stirred for 5 minutes, and then turbid liquid A was poured in and stirred evenly again. After curing at 25℃ for 14 days, the residual concentration of petroleum hydrocarbons in the soil was tested.

[0052] Figure 2 The figure shows the effect of heat treatment temperature and time on the catalytic performance of zeolite-magnetic iron oxide in alkali-heat combined modified zeolite. It can be seen from the figure that with the increase of heat treatment temperature and time, the catalytic performance of zeolite-magnetic iron oxide can be significantly improved, further promoting the oxidation of petroleum hydrocarbons by sodium percarbonate and improving the remediation efficiency of petroleum hydrocarbon contaminated soil. Example 2: Effect of the mass of scrap iron and the volume ratio of concentrated sulfuric acid on the catalytic performance of zeolite-magnetic iron oxide

[0053] The zeolite was put into 0.2mol / L sodium hydroxide solution, the mass ratio of zeolite to sodium hydroxide solution (g / L) was 60:1, heated and stirred at 100°C for 24h, cooled to room temperature, soaked for 72h, and solid-liquid separation was performed. The solid obtained by solid-liquid separation was washed with deionized water and placed in a muffle furnace for heat treatment, the heating temperature was controlled at 600°C, and the heating time was controlled at 8h to obtain alkali-heat combined modified zeolite.

[0054] The scrap iron was added to concentrated sulfuric acid in a mass volume ratio (g / mL) of 1:5, 1:7 and 1:9, respectively, and stirred for 24 hours. The obtained mixture was separated into solid and liquid, and the obtained filtrate was retained and deionized water was added to obtain an iron-containing filtrate, and the amount of deionized water was 4 times the volume of concentrated sulfuric acid. 0.2 mol / L sodium hydroxide solution was added to the iron-containing filtrate, and the pH of the solution was adjusted to 7 to form a stable iron hydroxide colloid.

[0055] The alkali-heat modified zeolite was added to the iron hydroxide colloid, and the volume ratio (g / mL) of the alkali-heat modified zeolite mass to the iron hydroxide colloid solution was 0.5:10. The mixture was stirred for 24 hours, and then the solid-liquid separation was performed, and the solid matter was washed with deionized water. The obtained solid matter was placed in a muffle furnace and heated for 8 hours at a heating temperature of 600°C. The heated solid matter was placed in a hydrogen atmosphere and heated for 4 hours at a hydrogen flow rate of 50 ml / min and a heating temperature of 600°C to obtain zeolite-magnetic iron oxide.

[0056] Take petroleum hydrocarbon contaminated soil for pretreatment. Mix and stir sodium percarbonate, Tween-80, silica sol and water, the mass ratio of sodium percarbonate, Tween-80 and silica sol is 1:0.5:0.1, and the ratio of the volume of water added to the total mass of sodium percarbonate, Tween-80 and silica sol (mL / g) is 5:1, and turbid liquid A is prepared; zeolite-magnetic iron oxide material, lactic acid, silica sol and water are mixed and stirred (the mass concentration of silica sol used is 30%), wherein the mass ratio of sodium percarbonate to zeolite-magnetic iron oxide material is 1:0.5, the mass ratio of zeolite-magnetic iron oxide material, lactic acid and silica sol is 1:1:0.1, and the ratio of the volume of water added to the total mass of zeolite-magnetic iron oxide material, lactic acid and silica sol (mL / g) is 3:1, and turbid liquid B is prepared. Pour turbid liquid B into the petroleum hydrocarbon contaminated soil, pre-stir for 5 minutes, then pour turbid liquid A into it, and stir evenly again. After curing at 25℃ for 14 days, the residual concentration of petroleum hydrocarbons in the soil was tested.

[0057] Figure 3 This is a graph showing the effect of the mass of scrap iron and the volume ratio of concentrated sulfuric acid on the catalytic performance of zeolite-magnetic iron oxide. It can be seen from the figure that the increase of concentrated sulfuric acid can increase the content of dissolved iron elements, thereby increasing the content of zeolite-magnetic oxide, improving the catalytic performance of sodium percarbonate, further promoting the oxidation of petroleum hydrocarbons by sodium percarbonate, and improving the remediation efficiency of petroleum hydrocarbon-contaminated soil.

[0058] Example 3: Effect of the mass ratio of zeolite modified by alkali-heat and the volume ratio of ferric hydroxide colloidal solution on the catalytic performance of zeolite-magnetic iron oxide

[0059] The zeolite was put into 0.2mol / L sodium hydroxide solution, the mass ratio of zeolite to sodium hydroxide solution (g / L) was 60:1, heated and stirred at 100°C for 24h, cooled to room temperature, soaked for 72h, and solid-liquid separation was performed. The solid obtained by solid-liquid separation was washed with deionized water and placed in a muffle furnace for heat treatment, the heating temperature was controlled at 600°C, and the heating time was controlled at 8h to obtain alkali-heat combined modified zeolite.

[0060] Put the scrap iron into concentrated sulfuric acid, the mass ratio of scrap iron to concentrated sulfuric acid (g / mL) is 1:3, and stir continuously for 24 hours. The obtained mixture is separated into solid and liquid, and the obtained filtrate is retained and deionized water is added to obtain an iron-containing filtrate, and the amount of deionized water is 4 times the volume of concentrated sulfuric acid. Add 0.2 mol / L sodium hydroxide solution to the iron-containing filtrate, adjust the solution pH to 7, and form a stable iron hydroxide colloid.

[0061] The alkali-heat modified zeolite was added to the iron hydroxide colloid at a mass volume ratio (g / mL) of 1:10, 2:10 and 3:10, respectively, and stirred for 24 hours, followed by solid-liquid separation, and the solid matter was washed with deionized water. The obtained solid matter was placed in a muffle furnace and heated for 8 hours at a heating temperature of 600°C. The heated solid matter was placed in a hydrogen atmosphere and heated for 4 hours at a hydrogen flow rate of 50 ml / min and a heating temperature of 600°C to obtain zeolite-magnetic iron oxide.

[0062] Take petroleum hydrocarbon contaminated soil for pretreatment. Sodium percarbonate, Tween-80, silica sol and water were mixed and stirred, the mass ratio of sodium percarbonate, Tween-80 and silica sol was 1:0.5:0.1, and the ratio of the volume of water added to the total mass of sodium percarbonate, Tween-80 and silica sol (mL / g) was 5:1, and turbid liquid A was prepared; zeolite-magnetic iron oxide material, lactic acid, silica sol (the mass concentration of silica sol used was 30%) and water were mixed and stirred, wherein the mass ratio of sodium percarbonate to zeolite-magnetic iron oxide material was 1:0.5, the mass ratio of zeolite-magnetic iron oxide material, lactic acid and silica sol was 1:1:0.1, and the ratio of the volume of water added to the total mass of zeolite-magnetic iron oxide material, lactic acid and silica sol (mL / g) was 3:1, and turbid liquid B was prepared. Turbid liquid B was poured into the petroleum hydrocarbon contaminated soil, pre-stirred for 5 minutes, and then turbid liquid A was poured in and stirred evenly again. After curing at 25℃ for 14 days, the residual concentration of petroleum hydrocarbons in the soil was tested.

[0063] Figure 4 This is a graph showing the influence of the mass of alkali-heat modified zeolite and the volume ratio of ferric hydroxide colloidal solution on the catalytic performance of zeolite-magnetic iron oxide. It can be seen from the figure that when the volume ratio of zeolite mass to ferric hydroxide colloidal solution (g / mL) is 2:10, zeolite-magnetic oxide has the best catalytic performance for sodium percarbonate, thereby achieving the optimal petroleum hydrocarbon contaminated soil remediation efficiency.

[0064] Example 4: Effect of hydrogen flow rate and corresponding thermal environment temperature on the catalytic performance of zeolite-magnetic iron oxide

[0065] The zeolite was put into 0.2mol / L sodium hydroxide solution, the mass ratio of zeolite to sodium hydroxide solution (g / L) was 60:1, heated and stirred at 100°C for 24h, cooled to room temperature, soaked for 72h, and solid-liquid separation was performed. The solid obtained by solid-liquid separation was washed with deionized water and placed in a muffle furnace for heat treatment, the heating temperature was controlled at 600°C, and the heating time was controlled at 8h to obtain alkali-heat combined modified zeolite.

[0066] Put the scrap iron into concentrated sulfuric acid, the mass ratio of scrap iron to concentrated sulfuric acid (g / mL) is 1:3, and stir continuously for 24 hours. The obtained mixture is separated into solid and liquid, and the obtained filtrate is retained and deionized water is added to obtain an iron-containing filtrate, and the amount of deionized water is 4 times the volume of concentrated sulfuric acid. Add 0.2 mol / L sodium hydroxide solution to the iron-containing filtrate, adjust the solution pH to 7, and form a stable iron hydroxide colloid.

[0067] The alkali-heat modified zeolite was added to the iron hydroxide colloid, and the volume ratio (g / mL) of the alkali-heat modified zeolite mass to the iron hydroxide colloid solution was 0.5:10. The mixture was stirred for 24 hours, and then the solid-liquid separation was performed, and the solid matter was washed with deionized water. The obtained solid matter was placed in a muffle furnace and heated for 8 hours at a heating temperature of 600°C. The heated solid matter was placed in a hydrogen atmosphere and heated for 4 hours, and the hydrogen flow rate was controlled to 100ml / min, 200ml / min, 300ml / min, 400ml / min and 500ml / min, respectively, and the heating temperature was 600°C to obtain zeolite-magnetic iron oxide.

[0068] Take petroleum hydrocarbon contaminated soil for pretreatment. Sodium percarbonate, Tween-80, silica sol and water were mixed and stirred, the mass ratio of sodium percarbonate, Tween-80 and silica sol was 1:0.5:0.1, and the ratio of the volume of water added to the total mass of sodium percarbonate, Tween-80 and silica sol (mL / g) was 5:1, and turbid liquid A was prepared; zeolite-magnetic iron oxide material, lactic acid, silica sol (the mass concentration of silica sol used was 30%) and water were mixed and stirred, wherein the mass ratio of sodium percarbonate to zeolite-magnetic iron oxide material was 1:0.5, the mass ratio of zeolite-magnetic iron oxide material, lactic acid and silica sol was 1:1:0.1, and the ratio of the volume of water added to the total mass of zeolite-magnetic iron oxide material, lactic acid and silica sol (mL / g) was 3:1, and turbid liquid B was prepared. Turbid liquid B was poured into the petroleum hydrocarbon contaminated soil, pre-stirred for 5 minutes, and then turbid liquid A was poured in and stirred evenly again. After curing at 25℃ for 14 days, the residual concentration of petroleum hydrocarbons in the soil was tested.

[0069] Figure 5This is a graph showing the effect of hydrogen flow rate on the catalytic performance of zeolite-magnetic iron oxide. It can be seen from the figure that when the hydrogen flow rate is 300 ml / min, the catalytic performance of zeolite-magnetic iron oxide reaches the best, thereby catalyzing the sodium percarbonate to oxidize petroleum hydrocarbons and achieving the optimal contaminated soil remediation efficiency.

[0070] Example 5: Effect of heat treatment temperature in hydrogen reduction process on catalytic performance of zeolite-magnetic iron oxide

[0071] The zeolite was put into 0.2mol / L sodium hydroxide solution, the mass ratio of zeolite to sodium hydroxide solution (g / L) was 60:1, heated and stirred at 100°C for 24h, cooled to room temperature, soaked for 72h, and solid-liquid separation was performed. The solid obtained by solid-liquid separation was washed with deionized water and placed in a muffle furnace for heat treatment, the heating temperature was controlled at 600°C, and the heating time was controlled at 8h, respectively, to obtain alkali-heat combined modified zeolite.

[0072] Put the scrap iron into concentrated sulfuric acid, the mass ratio of scrap iron to concentrated sulfuric acid (g / mL) is 1:3, and stir continuously for 24 hours. The obtained mixture is separated into solid and liquid, and the obtained filtrate is retained and deionized water is added to obtain an iron-containing filtrate, and the amount of deionized water is 4 times the volume of concentrated sulfuric acid. Add 0.2 mol / L sodium hydroxide solution to the iron-containing filtrate, adjust the solution pH to 7, and form a stable iron hydroxide colloid.

[0073] The alkali-heat modified zeolite was added to the iron hydroxide colloid, and the volume ratio (g / mL) of the alkali-heat modified zeolite mass to the iron hydroxide colloid solution was 0.5:10. The mixture was stirred for 24 hours, and then the solid-liquid separation was performed, and the solid matter was washed with deionized water. The obtained solid matter was placed in a muffle furnace and heated for 8 hours at a heating temperature of 600°C. The heated solid matter was placed in a hydrogen atmosphere and heated for 4 hours at a hydrogen flow rate of 50 ml / min. The heating temperatures were controlled at 700°C, 800°C, 900°C and 1000°C, respectively, to obtain zeolite-magnetic iron oxide.

[0074] Take petroleum hydrocarbon contaminated soil for pretreatment. Sodium percarbonate, Tween-80, silica sol and water were mixed and stirred, the mass ratio of sodium percarbonate, Tween-80 and silica sol was 1:0.5:0.1, and the ratio of the volume of water added to the total mass of sodium percarbonate, Tween-80 and silica sol (mL / g) was 5:1, and turbid liquid A was prepared; zeolite-magnetic iron oxide material, lactic acid, silica sol (the mass concentration of silica sol used was 30%) and water were mixed and stirred, wherein the mass ratio of sodium percarbonate to zeolite-magnetic iron oxide material was 1:0.5, the mass ratio of zeolite-magnetic iron oxide material, lactic acid and silica sol was 1:1:0.1, and the ratio of the volume of water added to the total mass of zeolite-magnetic iron oxide material, lactic acid and silica sol (mL / g) was 3:1, and turbid liquid B was prepared. Turbid liquid B was poured into the petroleum hydrocarbon contaminated soil, pre-stirred for 5 minutes, and then turbid liquid A was poured in and stirred evenly again. After curing at 25℃ for 14 days, the residual concentration of petroleum hydrocarbons in the soil was tested.

[0075] Figure 6 This is a graph showing the effect of heat treatment temperature in the hydrogen reduction process on the catalytic performance of zeolite-magnetic iron oxide. It can be seen from the figure that when the heat treatment temperature in the hydrogen reduction process is 900°C, the catalytic performance of zeolite-magnetic iron oxide reaches the best, thereby catalyzing sodium percarbonate to oxidize petroleum hydrocarbons and achieving the optimal contaminated soil remediation efficiency.

[0076] Example 6: Effect of the mass ratio of sodium percarbonate, Tween-80 and silica sol on the degradation of petroleum hydrocarbons

[0077] The zeolite was put into 0.2mol / L sodium hydroxide solution, the mass ratio of zeolite to sodium hydroxide solution (g / L) was 60:1, heated and stirred at 100°C for 24h, cooled to room temperature, soaked for 72h, and solid-liquid separation was performed. The solid obtained by solid-liquid separation was washed with deionized water and placed in a muffle furnace for heat treatment, the heating temperature was controlled at 600°C, and the heating time was controlled at 8h, respectively, to obtain alkali-heat combined modified zeolite.

[0078] Put the scrap iron into concentrated sulfuric acid, the mass ratio of scrap iron to concentrated sulfuric acid (g / mL) is 1:3, and stir continuously for 24 hours. The obtained mixture is separated into solid and liquid, and the obtained filtrate is retained and deionized water is added to obtain an iron-containing filtrate, and the amount of deionized water is 4 times the volume of concentrated sulfuric acid. Add 0.2 mol / L sodium hydroxide solution to the iron-containing filtrate, adjust the solution pH to 7, and form a stable iron hydroxide colloid.

[0079] The alkali-heat modified zeolite was added to the iron hydroxide colloid, and the volume ratio (g / mL) of the alkali-heat modified zeolite mass to the iron hydroxide colloid solution was 0.5:10. The mixture was stirred for 24 hours, and then the solid-liquid separation was performed, and the solid matter was washed with deionized water. The obtained solid matter was placed in a muffle furnace and heated for 8 hours at a heating temperature of 600°C. The heated solid matter was placed in a hydrogen atmosphere and heated for 4 hours at a hydrogen flow rate of 50 ml / min and a heating temperature of 600°C to obtain zeolite-magnetic iron oxide.

[0080] Petroleum hydrocarbon contaminated soil was pretreated. Sodium percarbonate, Tween-80, silica sol and water were mixed and stirred, the mass ratios of sodium percarbonate, Tween-80 and silica sol were 2:1:0.1, 2:1.5:0.1 and 3:1.5:0.2 respectively, the ratio of the volume of water added to the total mass of sodium percarbonate, Tween-80 and silica sol (mL / g) was 5:1, and turbid liquid A was obtained; zeolite-magnetic iron oxide material, lactic acid, silica sol (the mass concentration of silica sol used was 30%) and water were mixed and stirred, wherein the mass ratio of sodium percarbonate to zeolite-magnetic iron oxide material was 1:0.5, the mass ratio of zeolite-magnetic iron oxide material, lactic acid and silica sol was 1:1:0.1, and the ratio of the volume of water added to the total mass of zeolite-magnetic iron oxide material, lactic acid and silica sol (mL / g) was 3:1, and turbid liquid B was obtained. Pour turbid liquid B into the petroleum hydrocarbon contaminated soil, pre-stir for 5 minutes, then pour turbid liquid A into it and stir evenly again. Curing at 25℃ for 14 days, test the residual concentration of petroleum hydrocarbons in the soil.

[0081] Figure 7 This is an influence diagram of the mass ratio of sodium percarbonate, Tween-80 and silica sol on the degradation effect of petroleum hydrocarbons. It can be seen from the figure that when the mass ratio of sodium percarbonate, Tween-80 and silica sol is 2:1.5:0.1, the remediation efficiency of the remediation system for petroleum hydrocarbon contaminated soil can reach the optimal level.

[0082] Example 7: Effect of the mass ratio of sodium percarbonate to zeolite-magnetic iron oxide on the degradation of petroleum hydrocarbons

[0083] The zeolite was put into 0.2mol / L sodium hydroxide solution, the mass ratio of zeolite to sodium hydroxide solution (g / L) was 60:1, heated and stirred at 100°C for 24h, cooled to room temperature, soaked for 72h, and solid-liquid separation was performed. The solid obtained by solid-liquid separation was washed with deionized water and placed in a muffle furnace for heat treatment, the heating temperature was controlled at 600°C, and the heating time was controlled at 8h, respectively, to obtain alkali-heat combined modified zeolite.

[0084] Put the scrap iron into concentrated sulfuric acid, the mass ratio of scrap iron to concentrated sulfuric acid (g / mL) is 1:3, and stir continuously for 24 hours. The obtained mixture is separated into solid and liquid, and the obtained filtrate is retained and deionized water is added to obtain an iron-containing filtrate, and the amount of deionized water is 4 times the volume of concentrated sulfuric acid. Add 0.2 mol / L sodium hydroxide solution to the iron-containing filtrate, adjust the solution pH to 7, and form a stable iron hydroxide colloid.

[0085] The alkali-heat modified zeolite was added to the iron hydroxide colloid, and the volume ratio (g / mL) of the alkali-heat modified zeolite mass to the iron hydroxide colloid solution was 0.5:10. The mixture was stirred for 24 hours, and then the solid-liquid separation was performed, and the solid matter was washed with deionized water. The obtained solid matter was placed in a muffle furnace and heated for 8 hours at a heating temperature of 600°C. The heated solid matter was placed in a hydrogen atmosphere and heated for 4 hours at a hydrogen flow rate of 50 ml / min and a heating temperature of 600°C to obtain zeolite-magnetic iron oxide.

[0086] Petroleum hydrocarbon contaminated soil was pretreated. Sodium percarbonate, Tween-80, silica sol and water were mixed and stirred, the mass ratio of sodium percarbonate, Tween-80 and silica sol was 1:0.5:0.1, and the ratio of the volume of water added to the total mass of sodium percarbonate, Tween-80 and silica sol (mL / g) was 5:1, and turbid liquid A was obtained; zeolite-magnetic iron oxide material, lactic acid, silica sol (the mass concentration of silica sol used was 30%) and water were mixed and stirred, wherein the mass ratio of sodium percarbonate to zeolite-magnetic iron oxide material was 1:1, 1:2, 1:4, 5:1, 4:1 and 3:1 respectively, the mass ratio of zeolite-magnetic iron oxide material, lactic acid and silica sol was 1:1:0.1, and the ratio of the volume of water added to the total mass of zeolite-magnetic iron oxide material, lactic acid and silica sol (mL / g) was 3:1, and turbid liquid B was obtained. Pour turbid liquid B into the petroleum hydrocarbon contaminated soil, pre-stir for 5 minutes, then pour turbid liquid A into it and stir evenly again. Curing at 25℃ for 14 days, test the residual concentration of petroleum hydrocarbons in the soil.

[0087] Figure 8 This is the influence of the mass ratio of sodium percarbonate to zeolite-magnetic iron oxide on the degradation effect of petroleum hydrocarbons. It can be seen from the figure that when the mass ratio of sodium percarbonate to zeolite-magnetic iron oxide is 5:1, the remediation efficiency of the remediation system for petroleum hydrocarbon contaminated soil can reach the optimal level.

[0088] Example 8: Effect of the mass ratio of zeolite-magnetic iron oxide material, lactic acid and silica sol on the degradation effect of petroleum hydrocarbons

[0089] The zeolite was put into 0.2mol / L sodium hydroxide solution, the mass ratio of zeolite to sodium hydroxide solution (g / L) was 60:1, heated and stirred at 100°C for 24h, cooled to room temperature, soaked for 72h, and solid-liquid separation was performed. The solid obtained by solid-liquid separation was washed with deionized water and placed in a muffle furnace for heat treatment, the heating temperature was controlled at 600°C, and the heating time was controlled at 8h to obtain alkali-heat combined modified zeolite.

[0090] Put the scrap iron into concentrated sulfuric acid, the mass ratio of scrap iron to concentrated sulfuric acid (g / mL) is 1:3, and stir continuously for 24 hours. The obtained mixture is separated into solid and liquid, and the obtained filtrate is retained and deionized water is added to obtain an iron-containing filtrate, and the amount of deionized water is 4 times the volume of concentrated sulfuric acid. Add 0.2 mol / L sodium hydroxide solution to the iron-containing filtrate, adjust the solution pH to 7, and form a stable iron hydroxide colloid.

[0091] The alkali-heat modified zeolite was added to the iron hydroxide colloid, and the volume ratio (g / mL) of the alkali-heat modified zeolite mass to the iron hydroxide colloid solution was 0.5:10. The mixture was stirred for 24 hours, and then the solid-liquid separation was performed, and the solid matter was washed with deionized water. The obtained solid matter was placed in a muffle furnace and heated for 8 hours at a heating temperature of 600°C. The heated solid matter was placed in a hydrogen atmosphere and heated for 4 hours at a hydrogen flow rate of 50 ml / min and a heating temperature of 600°C to obtain zeolite-magnetic iron oxide.

[0092] Take petroleum hydrocarbon contaminated soil for pretreatment. Sodium percarbonate, Tween-80, silica sol and water were mixed and stirred, the mass ratio of sodium percarbonate, Tween-80 and silica sol was 1:0.5:0.1, and the ratio of the volume of water added to the total mass of sodium percarbonate, Tween-80 and silica sol (mL / g) was 5:1, to obtain turbid liquid A; zeolite-magnetic iron oxide material, lactic acid, silica sol (the mass concentration of silica sol used was 30%) and water were mixed and stirred, wherein the mass ratio of sodium percarbonate to zeolite-magnetic iron oxide material was 1:0.5, the mass ratios of zeolite-magnetic iron oxide material, lactic acid and silica sol were 1:2:0.1, 1:3:0.1, 1.5:2:0.1, 1.5:3:0.1, 1:2:0.2 and 1:2:0.3 respectively, and the ratio of the volume of water added to the total mass of zeolite-magnetic iron oxide material, lactic acid and silica sol was 3:1 (mL / g), to obtain turbid liquid B. Pour turbid liquid B into the petroleum hydrocarbon contaminated soil, pre-stir for 5 minutes, then pour turbid liquid A into it and stir evenly again. Curing at 25℃ for 14 days, test the residual concentration of petroleum hydrocarbons in the soil.

[0093] Fig. 9This is an influence diagram of the mass ratio of zeolite-magnetic iron oxide material, lactic acid and silica sol on the degradation effect of petroleum hydrocarbons. It can be seen from the figure that when the mass ratio of zeolite-magnetic iron oxide material, lactic acid and silica sol is 1.5:3:0.1, the remediation efficiency of the remediation system for petroleum hydrocarbon contaminated soil can reach the optimal level.

[0094] Example 9: Preparation of zeolite-magnetic iron oxide by replacing scrap iron with steel slag

[0095] The zeolite was put into 0.2mol / L sodium hydroxide solution, the mass ratio of zeolite to sodium hydroxide solution (g / L) was 60:1, heated and stirred at 100°C for 24h, cooled to room temperature, soaked for 72h, and solid-liquid separation was performed. The solid obtained by solid-liquid separation was washed with deionized water and placed in a muffle furnace for heat treatment, the heating temperature was controlled at 600°C, and the heating time was controlled at 8h to obtain alkali-heat combined modified zeolite.

[0096] Put the steel slag into concentrated sulfuric acid, the steel slag mass to concentrated sulfuric acid volume ratio (g / mL) is 1:3, and stir continuously for 24 hours. The obtained mixture is separated into solid and liquid, and the obtained filtrate is retained and deionized water is added to obtain an iron-containing filtrate, and the amount of deionized water is 4 times the volume of concentrated sulfuric acid. Add 0.2 mol / L sodium hydroxide solution to the iron-containing filtrate, adjust the solution pH to 7, and form a stable iron hydroxide colloid.

[0097] The alkali-heat modified zeolite was added to the iron hydroxide colloid, and the volume ratio (g / mL) of the alkali-heat modified zeolite mass to the iron hydroxide colloid solution was 0.5:10. Stirring was continued for 24 hours, followed by solid-liquid separation, and the solid matter was washed with deionized water. The obtained solid matter was placed in a muffle furnace and heated for 8 hours at a heating temperature of 600°C. The heated solid matter was placed in a hydrogen atmosphere and heated for 4 hours at a hydrogen flow rate of 50 ml / min and a heating temperature of 600°C to obtain zeolite-magnetic iron oxide, which was labeled as zeolite-ferroferric oxide.

[0098] Take petroleum hydrocarbon contaminated soil for pretreatment. Sodium percarbonate, Tween-80, silica sol and water were mixed and stirred, the mass ratio of sodium percarbonate, Tween-80 and silica sol was 1:0.5:0.1, and the ratio of the volume of water added to the total mass of sodium percarbonate, Tween-80 and silica sol (mL / g) was 5:1, and turbid liquid A was prepared; zeolite-ferroferric oxide material, citric acid, silica sol (the mass concentration of silica sol used was 30%) and water were mixed and stirred, wherein the mass ratio of sodium percarbonate to zeolite-magnetic iron oxide material was 1:0.5, the mass ratio of zeolite-ferroferric oxide material, citric acid and silica sol was 1.5:3:0.1, and the ratio of the volume of water added to the total mass of zeolite-ferroferric oxide material, citric acid and silica sol (mL / g) was 3:1, and turbid liquid B was prepared. Turbid liquid B was poured into the petroleum hydrocarbon contaminated soil, pre-stirred for 5 minutes, and then turbid liquid A was poured in and stirred again. After curing for 14 days at 25℃, the degradation of petroleum hydrocarbons in the contaminated soil was completed. After the scrap iron was replaced with steel slag, the remediation efficiency was 73%, which was significantly lower than that when the raw material was scrap iron (remediation efficiency was 84%), indicating that the catalytic performance of the zeolite-magnetic iron oxide prepared from scrap iron was stronger than that of steel slag.

[0099] The present invention provides a method for preparing zeolite-magnetic iron oxide and its application. There are many methods and ways to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A method for preparing zeolite-magnetic iron oxide, characterized in that: The specific steps are: S1. treating the zeolite with alkali and then heat treating it to obtain an alkali-heat combined modified zeolite; S2. extracting the iron in the iron-containing byproduct with acid and preparing iron hydroxide colloid; S3. The alkali-heat combined modified zeolite and the iron hydroxide colloid are uniformly mixed, and after solid-liquid separation, heat treatment and hydrogen reduction treatment are performed to obtain the zeolite-magnetic iron oxide.

2. The preparation method according to claim 1, characterized in that: In S1, the specific process of the alkali treatment is: putting the zeolite into a sodium hydroxide solution, heating and stirring at 80-120° C. for 20-25 hours, soaking for 70-75 hours after cooling, and then washing after solid-liquid separation; wherein the mass volume ratio of the zeolite and the sodium hydroxide is (50-70):1; and the concentration of the sodium hydroxide solution is 0.1-0.3 mol / L.

3. The preparation method according to claim 1, characterized in that: In S1, the specific conditions of the heat treatment are: the temperature is controlled at 300-600°C, and the heating time is controlled at 8-12h.

4. The preparation method according to claim 1, characterized in that: The specific steps in S2 are: adding the iron-containing by-product into concentrated sulfuric acid at a mass volume ratio of 1: (3-9), stirring for 24 hours, adding deionized water 4 times the volume of concentrated sulfuric acid to the filtrate after solid-liquid separation to obtain an iron-containing filtrate, and adding sodium hydroxide solution to the iron-containing filtrate until the pH of the filtrate reaches 7, so as to obtain iron hydroxide colloid; wherein the iron-containing by-product is scrap iron and / or steel slag; and the concentration of the sodium hydroxide solution is 0.1-0.3 mol / L.

5. The preparation method according to claim 1, characterized in that: The specific steps in S3 are: uniformly mixing the alkali-heat combined modified zeolite and the iron hydroxide colloid in a mass volume ratio of (0.5-3):10, continuously stirring for 24 hours, washing the solid after solid-liquid separation, and then heating the solid at 600°C for 8 hours, and then heating the heated solid at 600-1000°C for 4 hours in a hydrogen atmosphere, wherein the flow rate of the hydrogen is 50-500 ml / min.

6. Zeolite-magnetic iron oxide prepared by the preparation method according to any one of claims 1 to 5.

7. Application of the zeolite-magnetic iron oxide according to claim 6 in the field of catalyzing sodium percarbonate to repair soil contaminated by petroleum hydrocarbons.

8. The use according to claim 7, characterized in that: The specific steps of the application are: S11. Sodium percarbonate, Tween-80, silica sol and water were mixed to prepare a turbid solution A; S22. The zeolite - magnetic iron oxide, organic acid, silica sol and water are uniformly mixed to prepare a turbid solution B; S33. Mix turbid liquid B and petroleum hydrocarbon contaminated soil evenly, then add turbid liquid A and mix evenly. Curing for 12 to 15 days to complete the restoration.

9. The use according to claim 8, characterized in that: In the turbid liquid A, the mass ratio of sodium percarbonate, Tween-80 and silica sol is (1-3):(0.5-1.5):(0.1-0.2), and the ratio of the volume of added water to the total mass of sodium percarbonate, Tween-80 and silica sol is 5:

1.

10. The use according to claim 8, characterized in that: The mass ratio of the sodium percarbonate to the zeolite-magnetic iron oxide material is (1-5):(0.5-4); in the turbid liquid B, the mass ratio of the zeolite-magnetic iron oxide, the organic acid, and the silica sol is (1-1.5):(1-3):(0.1-0.3), and the ratio of the volume of the added water to the total mass of the zeolite-magnetic iron oxide material, the lactic acid, and the silica sol is 3:1.

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