Zirconium oxide modified activated carbon and method for catalyzing potassium permanganate to deeply treat sewage by using zirconium oxide modified activated carbon

Abstract

The invention provides zirconia-modified activated carbon and a method for catalyzing potassium permanganate to deeply treat sewage by using the zirconia-modified activated carbon, and belongs to the field of sewage deep treatment. The preparation method of the zirconium oxide modified activated carbon comprises the following steps: (1) dissolving zirconium oxychloride in water, adding activated carbon according to the mass ratio of the zirconium oxychloride to the activated carbon being (1: 0.1)-(1: 1), and quickly stirring and uniformly mixing; and (2) dropwise adding an ammonia water solution under an ultrasonic condition until the pH value of the solution is adjusted to 7, fully precipitating, and drying the obtained mixture to obtain the zirconium oxide modified activated carbon AC (at) ZrO2. When in use, the AC-ZrO2 and potassium permanganate are added into sewage to be treated according to the mass ratio of 1: (0.01-0.1), so that effective treatment of new pollutants in the sewage can be realized. The preparation method and the application method are simple, the raw materials are cheap and easy to obtain, the sewage treatment cost is low, the catalytic efficiency is high, and large-scale sewage treatment is facilitated.

Description

Technical Field

[0001] The invention relates to the field of sewage deep treatment, and in particular to a zirconium oxide modified activated carbon (AC@ZrO2) and a method for deep treatment of sewage by catalyzing potassium permanganate thereof. Background Art

[0002] Vigorously developing sewage deep treatment and reuse technology is an important way to alleviate water resource shortage and ensure water ecological security.

[0003] In recent years, new pollutants have attracted widespread attention due to their biological toxicity, environmental persistence, bioaccumulation and other characteristics, which pose great risks to the ecological environment or human health. However, conventional sewage treatment processes cannot effectively remove new pollutants, so there is an urgent need to develop effective, low-cost deep treatment processes that do not produce by-products. Domestic and foreign scholars have carried out a lot of research on the removal of new pollutants in deep sewage treatment. Among them, advanced oxidation processes have attracted widespread attention due to their strong oxidizing properties, fast reaction speed, and easy-to-control operating conditions.

[0004] The characteristics of Advanced Oxidation Processes (AOPS) are to generate hydroxyl radicals (·OH) or sulfate radicals (SO4 ·- ), using the strong oxidizing property of free radicals to degrade and remove new pollutants in sewage. However, the background components of sewage (such as humus, halogen ions, etc.) have a capture effect on free radicals, which can easily interfere with the degradation process of new pollutants and easily generate toxic byproducts such as bromate.

[0005] In summary, considering the water quality characteristics of sewage, the oxidative capacity of free radicals will be greatly limited. How to deeply remove new pollutants in sewage is an urgent problem to be solved. Proper deep sewage treatment can not only reduce environmental risks, but also realize the recycling and reuse of clean water, which has important environmental and economic significance.

[0006] Potassium permanganate (KMnO4) has the advantages of low cost, easy storage and convenient addition. The KMnO4 pre-oxidation process has been widely used since the 1990s. Compared with ozone and chlorine dioxide, KMnO4 oxidation is less likely to produce toxic and harmful byproducts (such as bromate and chlorite). In recent years, studies have found that KMnO4 oxidation is selective and has a strong ability to resist interference from background components in sewage, but its oxidation efficiency for some new pollutants is not ideal. It is of great practical significance to develop potassium permanganate catalytic oxidation technology and improve its treatment efficiency for new pollutants in sewage.

[0007] Zirconia materials are becoming increasingly promising catalysts or catalyst carrier materials due to their diverse crystal structures, unique surface chemical properties and catalytic activity. Zirconia is commonly prepared by the sol-coagulation method. The nanoparticles obtained by this method have small particle size, large specific surface area and high material uniformity. However, the formed zirconia has serious agglomeration phenomenon, which directly affects its catalytic efficiency. It also leads to problems such as long drying time of zirconia during the preparation process, increasing the treatment cost. Therefore, directly adding zirconia for catalysis in the water treatment process is not the best treatment method.

[0008] In addition, the prior art still has great limitations in utilizing the performance of zirconium oxide materials. For example, CN109173988A provides a magnetic composite activated carbon, a preparation method and its application in organic wastewater treatment, wherein the utilization of zirconium oxide is mainly to provide more active sites, and the performance of zirconium oxide needs to be further explored. Summary of the invention

[0009] In view of the above problems existing in the prior art, the present invention provides a method for treating sewage by catalyzing potassium permanganate using zirconium oxide modified activated carbon and the like. The preparation method and application method of the present invention are relatively simple, the raw materials are cheap and readily available, the cost of treating sewage is low, the catalytic efficiency is high, and it is conducive to large-scale sewage treatment.

[0010] The technical solution of the present invention is as follows:

[0011] A zirconium oxide modified activated carbon, characterized in that the preparation method of the zirconium oxide modified activated carbon comprises the following steps:

[0012] (1) dissolving zirconium oxychloride in water, adding activated carbon in a ratio of zirconium oxychloride to activated carbon of 1:0.1-1:1 by mass, and rapidly stirring to mix well;

[0013] (2) Adding an aqueous ammonia solution dropwise under ultrasonic conditions until the pH of the solution is adjusted to 7, and drying the obtained mixture after sufficient precipitation to obtain zirconium oxide modified activated carbon AC@ZrO2.

[0014] Preferably, in step (1), the concentration of zirconium oxychloride after being dissolved in water is 0.05-0.2 mol / L.

[0015] Preferably, the mass fraction of the ammonia solution in step (2) is 25-35wt%.

[0016] Preferably, the drying temperature in step (2) is 50-80° C. and the drying time is 12-24 hours.

[0017] The present invention also provides the use of the zirconium oxide modified activated carbon in catalyzing potassium permanganate to deeply treat sewage. When used, AC@ZrO2 and potassium permanganate are added to the sewage to be treated at a mass ratio of 1:0.01-0.1, thereby effectively treating new pollutants in the sewage.

[0018] Furthermore, the sewage to be treated includes wastewater from a sewage treatment plant from which new pollutants have not yet been removed.

[0019] Furthermore, the new pollutants include phenolic organic pollutants.

[0020] Furthermore, the concentration range of the phenolic organic pollutants is 0.01-100 mg / L.

[0021] The beneficial technical effects of the present invention are:

[0022] 1. Aiming at the practical problem of deep treatment of new pollutants in sewage, the inventor conducted in-depth research and obtained a new reaction principle different from the existing technology: the present invention combines activated carbon and zirconium oxide to form a ternary complex with potassium permanganate and organic matter. The reaction process and principle are as follows: Figure 1 As shown in the figure, it can be seen that zirconium oxide modified activated carbon can effectively catalyze potassium permanganate to form active KMnO4 complex (AC@ZrO2—KMnO4*—organic pollutants), capture the electrons of organic pollutants in the water phase, and thus accelerate the decomposition of organic matter. Zirconium oxide modified activated carbon catalyzes potassium permanganate for deep sewage treatment, achieving efficient removal of new pollutants in sewage, and at the same time is conducive to improving the utilization rate of electrons in sewage.

[0023] In the prior art, the catalytic oxidation of potassium permanganate usually relies on the reduction of potassium permanganate, while the catalytic zirconia modified activated carbon in the present invention does not rely on the reduction of potassium permanganate, but uses the highly active complex formed by the zirconia modified activated carbon and potassium permanganate to achieve the degradation of organic pollutants in water, which greatly improves the utilization rate of potassium permanganate and provides an effective method for the deep treatment of new pollutants in sewage. In addition, the present invention does not utilize zirconium oxide to provide more active sites, but generates AC@ZrO2, and then forms a ternary complex with potassium permanganate and organic matter to play a role. If the ternary complex cannot be formed, the promotion effect cannot be produced.

[0024] 2. The present invention selects zirconium oxychloride as a precursor, undergoes hydrolysis and condensation reactions, forms a stable sol system in the solution, and then utilizes the strong adsorption properties of activated carbon to adsorb it on the surface of activated carbon. With the addition of ammonia water, the surface debris of the activated carbon is significantly reduced and it is sunken inward to produce a large number of grooves. The pore size in the grooves is uniform, which is more conducive to the uniform and tight combination of the zirconium oxide formed in situ and the activated carbon. It is not easy to fall off during the catalytic process and can maintain the catalytic efficiency for a long time.

[0025] 3. The method of modifying activated carbon with zirconium oxide of the present invention is applicable to activated carbons of different sources and shapes, is easy to operate, and the raw materials are easily obtained, inexpensive, and convenient to use. The prepared AC@ZrO2 zirconium oxide is strongly adsorbed on the surface of activated carbon, has stronger stability, and is not easy to fall off during the reaction. The surface of zirconium oxide is acidic and alkaline, and has unique catalytic activity. The modified activated carbon can make the zirconium oxide particles more evenly dispersed, catalyze potassium permanganate to capture organic electrons, and achieve efficient treatment of new pollutants in sewage, thereby improving the utilization rate of electrons in wastewater. At the same time, the use of zirconium oxide to modify activated carbon catalysis can avoid the agglomeration phenomenon that affects the catalytic efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the process and principle of potassium permanganate catalyzed by zirconium oxide modified activated carbon to capture electrons of organic pollutants in the aqueous phase.

[0027] Figure 2 The figure is a comparison diagram of the effects of degrading diclofenac by the conventional potassium permanganate oxidation method and the method of the present invention. DETAILED DESCRIPTION

[0028] The present invention is described in detail below in conjunction with the accompanying drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Embodiment 1:

[0030] This embodiment provides a method for preparing zirconium oxide modified activated carbon, comprising the following steps:

[0031] (1) dissolving 10 g of zirconium oxychloride in water to obtain a 0.1 mol / L zirconium oxychloride solution, then adding 10 g of activated carbon, and rapidly stirring to mix well;

[0032] (2) Under ultrasonic conditions, a 27 wt % ammonia solution was added dropwise until the pH of the solution was adjusted to 7. After sufficient precipitation, the obtained mixture was dried at 60° C. for 18 h to obtain zirconium oxide modified activated carbon AC@ZrO2.

[0033] The obtained product is a granular powder, which is more conducive to the uniform and tight combination of the zirconium oxide formed in situ and the activated carbon, is not easy to fall off during the catalytic process, and can maintain the catalytic efficiency for a long time. The zirconium oxide modified activated carbon in the present invention can form a highly active complex with potassium permanganate to capture the electrons of new pollutants in sewage, thereby accelerating the decomposition of organic matter. Zirconium oxide modified activated carbon catalyzes potassium permanganate for the treatment of deep sewage, achieving efficient removal of new pollutants in sewage, and at the same time is conducive to improving the utilization rate of electrons in sewage.

[0034] Application Example 1:

[0035] The AC@ZrO2 and potassium permanganate prepared in Example 1 were added to simulated sewage at a mass ratio of 1:0.02. The sewage contained 1.6 mg / L of diclofenac, and the concentration of AC@ZrO2 was 0.5 g / L and the concentration of potassium permanganate was 0.01 g / L. Ordinary potassium permanganate was used as a control group, and potassium permanganate (0.01 g / L) was added to the same volume of sewage. The experiments were carried out under the conditions of pH 5 and 7 of the sewage, respectively. The process and principle of the zirconium oxide modified activated carbon catalyzing potassium permanganate to capture electrons of organic pollutants in the aqueous phase in the experiment are shown as follows Figure 1 shown.

[0036] The concentration of organic matter is detected by high performance liquid chromatography (HPLC). Liquid chromatography uses the difference in adsorption and solubility of different organic matter in the fixed mobile phase. When the mobile phase and the sample are mixed and enter the chromatogram together, different organic matter is repeatedly adsorbed and dissolved in the chromatographic column. The organic matter with strong adsorption or solubility is retained in the chromatographic column for a long time, and vice versa, the retention time is short, thus successfully separating different organic matter. The peak area ratio obtained, that is, [C] t / [C]0 can determine the change in organic matter concentration.

[0037] The concentration of diclofenac in sewage was detected by the above method. As time went by, the removal rates of diclofenac in the two groups of experiments were shown in Tables 1, 2 and Figure 2 As shown, Figure 2 This is the case when pH is 5.

[0038] Table 1 Removal rate at pH 5

[0039] time Potassium permanganate oxidation removal rate <![CDATA[Removal rate of potassium permanganate oxidation catalyzed by AC@ZrO2 <!-- 3 -->]]> 0 0 0 5 minutes 3.68％ 69.91％ 10 minutes 10.87％ 76.00％

[0040] Table 2 Removal rate at pH 7

[0041] time Potassium permanganate oxidation removal rate <![CDATA[Removal rate of potassium permanganate oxidation catalyzed by AC@ZrO2]]> 0 0 0 5 minutes 4.1％ 21.5％ 10 minutes 23.60％ 62.70％

[0042] From Table 1, Table 2 and Figure 2It can be seen that under the condition of pH 7, the addition of AC@ZrO2 promotes the degradation of diclofenac, but the degradation effect is not as significant as under acidic conditions at pH 5.

[0043] Application Example 2:

[0044] AC@ZrO2 and potassium permanganate prepared in Example 1 were added to simulated sewage at a mass ratio of 1:0.04. The sewage contained 1.6 mg / L diclofenac, the concentration of AC@ZrO2 added was 0.5 g / L, and the concentration of potassium permanganate was 0.02 g / L. Ordinary potassium permanganate was used as a control group, and potassium permanganate (0.02 g / L) was added to the same volume of sewage. The pH of the sewage was 5. The removal rate of diclofenac changed over time as shown in Table 3.

[0045] Table 3

[0046] time Potassium permanganate oxidation removal rate <![CDATA[Removal rate of potassium permanganate oxidation catalyzed by AC@ZrO2]]> 0 0 0 5 minutes 8.53％ 89.08％ 10 minutes 21.30％ 91.25％

[0047] Application Example 3:

[0048] AC@ZrO2 and potassium permanganate prepared in Example 1 were added to simulated sewage at a mass ratio of 1:0.1. The sewage contained 1.6 mg / L diclofenac, the concentration of AC@ZrO2 added was 0.5 g / L, and the concentration of potassium permanganate was 0.05 g / L. Ordinary potassium permanganate was used as a control group, and potassium permanganate (0.05 g / L) was added to the same volume of sewage. The pH of the sewage was 5. The removal rate of diclofenac changed over time as shown in Table 4.

[0049] Table 4

[0050] time Potassium permanganate oxidation removal rate <![CDATA[Removal rate of potassium permanganate oxidation catalyzed by AC@ZrO2]]> 0 0 0 2 minutes 17.90％ 82.3％ 5 minutes 31.80％ 88.4％

[0051] From the data in Tables 1 to 4, it can be seen that when the mass ratio of AC@ZrO2 to potassium permanganate is in the range of 1:0.01-0.1, as the concentration of potassium permanganate increases, the degradation of diclofenac also accelerates.

[0052] Application example 4:

[0053] AC@ZrO2 and potassium permanganate prepared in Example 1 were added to simulated sewage at a mass ratio of 1:0.02. The sewage contained 0.5 mg / L phenol, the concentration of AC@ZrO2 added was 0.5 g / L, and the concentration of potassium permanganate was 0.01 g / L. Ordinary potassium permanganate was used as a control group, and potassium permanganate (0.01 g / L) was added to the same volume of sewage. The pH of the sewage was 5. The change in the removal rate of phenol over time is shown in Table 5.

[0054] Table 5

[0055] time Potassium permanganate oxidation removal rate <![CDATA[Removal rate of potassium permanganate oxidation catalyzed by AC@ZrO2]]> 0 0 0 20 minutes 5.30％ 19.20％ 40 minutes 12.00％ 41.80％

[0056] Comparative Example 1:

[0057] AC@ZrO2 and potassium permanganate prepared in Example 1 were added to the sewage effluent from the sewage treatment plant at a mass ratio of 1:0.02. The sewage contained 0.5 mg / L atrazine (non-phenolic compound), the concentration of AC@ZrO2 was 0.5 g / L, and the concentration of potassium permanganate was 0.01 g / L. Ordinary potassium permanganate was used as a control group, and potassium permanganate (0.01 g / L) was added to the same volume of sewage. The pH of the sewage was 5. The change in the removal rate of atrazine over time is shown in Table 6.

[0058] Table 6

[0059] time Potassium permanganate oxidation removal rate <![CDATA[Removal rate of potassium permanganate oxidation catalyzed by AC@ZrO2]]> 0 0 0 20 minutes 0.08％ 1.2％ 40 minutes 0.1％ 3.6％

[0060] From the data of Comparative Example 1, it can be seen that the zirconium oxide modified activated carbon prepared by the present invention has a high selective catalytic activity for phenol pollutants, and whether it has an obvious catalytic degradation effect on other types of pollutants requires further study.

[0061] Comparative Example 2:

[0062] The activated carbon (AC) and potassium permanganate used in Example 1 were added to the sewage effluent from the sewage treatment plant at a mass ratio of 1:0.02, the sewage contained 0.5 mg / L diclofenac, and the concentration of potassium permanganate was 0.01 g / L. The pH of the sewage was 5. The removal rate of diclofenac changed with time as shown in Table 7.

[0063] Table 7

[0064] time AC catalytic potassium permanganate oxidation removal rate 0 0 5 minutes 7.1％ 10 minutes 18.6％

[0065] Comparative Example 3:

[0066] Zirconium oxide (ZrO2) and potassium permanganate used in Example 1 were added to the sewage effluent from the sewage treatment plant at a mass ratio of 1:0.02, the sewage contained 0.5 mg / L diclofenac, and the concentration of potassium permanganate was 0.01 g / L. The pH of the sewage was 5. The removal rate of diclofenac changed with time as shown in Table 8.

[0067] Table 8

[0068] time <![CDATA[Removal rate of potassium permanganate oxidation catalyzed by ZrO2]]> 0 0 5 minutes 17.6％ 10 minutes 21.8％

[0069] From the data of Comparative Examples 2 and 3, it can be seen that the effects of activated carbon or zirconium oxide alone catalyzing potassium permanganate to degrade diclofenac are not ideal. Therefore, the formation of AC@ZrO2-KMnO4*-organic pollutant active complex is an indispensable step in degrading organic pollutants, and is also the key mechanism of AC@ZrO2 catalyzing potassium permanganate to degrade diclofenac mentioned in the present invention.

[0070] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and implementation modes, and can be fully applicable to various fields suitable for the present invention. For those familiar with the art, for those of ordinary skill in the art, various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to specific details.

Claims

1. A zirconium oxide modified activated carbon, characterized in that: The preparation method of the zirconium oxide modified activated carbon comprises the following steps: (1) dissolving zirconium oxychloride in water, adding activated carbon in a ratio of zirconium oxychloride to activated carbon of 1:0.1-1:1 by mass, and rapidly stirring to mix well; (2) Adding an aqueous ammonia solution dropwise under ultrasonic conditions until the pH of the solution is adjusted to 7, and drying the obtained mixture after sufficient precipitation to obtain zirconium oxide modified activated carbon AC@ZrO2.

2. The zirconium oxide modified activated carbon according to claim 1, characterized in that In step (1), the concentration of zirconium oxychloride after being dissolved in water is 0.05-0.2 mol / L.

3. The zirconium oxide modified activated carbon according to claim 1, characterized in that The mass fraction of the ammonia solution in step (2) is 25-35wt%.

4. The zirconium oxide modified activated carbon according to claim 1, characterized in that The drying temperature in step (2) is 50-80° C. and the drying time is 12-24 hours.

5. Use of the zirconium oxide modified activated carbon according to any one of claims 1 to 4 in catalyzing potassium permanganate deep treatment of sewage, characterized in that: When in use, AC@ZrO2 and potassium permanganate are added to the sewage to be treated in a mass ratio of 1:0.01-0.1, so as to achieve effective treatment of new pollutants in the sewage.

6. The use according to claim 5, characterized in that: The sewage to be treated includes wastewater from the effluent of a sewage treatment plant from which new pollutants have not yet been removed.

7. The use according to claim 5, characterized in that: The new pollutants include phenolic organic pollutants.

8. The use according to claim 7, characterized in that: The concentration range of the phenolic organic pollutants is 0.01-100 mg / L.

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