Zirconium oxide modified activated carbon and method for deep treatment of sewage by catalyzing potassium permanganate

Abstract

The present invention provides a zirconium oxide modified activated carbon and a method for catalyzing potassium permanganate to deeply treat sewage, belonging 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 at a mass ratio of zirconium oxychloride to activated carbon of 1:0.1-1:1, and quickly stirring and mixing evenly; (2) adding an 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. 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, so as to achieve effective treatment of new pollutants in the sewage. The preparation method and application method of the present invention are relatively simple, the raw materials are cheap and easy to obtain, the cost of treating sewage is low, the catalytic efficiency is high, and it is conducive to large-scale sewage treatment.

Description

Technical Field

[0001] The present invention relates to the field of sewage deep treatment, and in particular to a zirconium oxide modified activated carbon (AC@ZrO 2 ) and a method for deep treatment of sewage by catalyzing potassium permanganate. 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 (SO 4 ·- ), 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 (KMnO 4 ) has the advantages of low cost, easy storage and convenient addition, KMnO 4 The pre-oxidation process has been widely used since the 1990s. Compared with ozone and chlorine dioxide, KMnO 4 It is not easy to produce toxic and harmful byproducts (such as bromate and chlorite) during the oxidation process. 4Oxidation 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 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@ZrO 2 .

[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@ZrO 2 Adding potassium permanganate and potassium permanganate into the sewage to be treated in a mass ratio of 1:0.01-0.1 can effectively treat 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 KMnO 4 Complex (AC@ZrO 2 —KMnO 4 *—organic pollutants), capturing the electrons of organic pollutants in the water phase, thereby accelerating 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 helping to improve the utilization rate of electrons in sewage.

[0023] In the prior art, potassium permanganate catalytic oxidation usually relies on potassium permanganate reduction, while the zirconium oxide modified activated carbon catalysis in the present invention does not rely on potassium permanganate reduction, but uses the highly active complex formed by zirconium oxide modified activated carbon and potassium permanganate to achieve the degradation of organic pollutants in water, greatly improving the utilization rate of potassium permanganate and providing an effective method for deep treatment of new pollutants in sewage. In addition, the present invention does not utilize zirconium oxide to provide more active sites, but to generate AC@ZrO 2 , and then form a ternary complex with potassium permanganate and organic matter to play a role. If the ternary complex cannot be formed, no promoting effect can 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 in the present invention is applicable to activated carbons from different sources and in different shapes, and is easy to operate, has easy-to-obtain raw materials, is inexpensive, and is convenient to use. 2 Zirconia is strongly adsorbed on the surface of activated carbon, with stronger stability and less likely to fall off during the reaction. The surface of zirconium oxide is both acidic and alkaline, with unique catalytic activity. The modified activated carbon can make the zirconium oxide particles more evenly dispersed, catalyzing potassium permanganate to capture organic electrons, achieving efficient treatment of new pollutants in sewage and improving the utilization rate of electrons in wastewater. At the same time, the use of zirconium oxide to modify activated carbon catalysis can avoid agglomeration and affect 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@ZrO prepared in Example 1 2 The AC@ZrO 2 The concentration of potassium permanganate 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 sewage. The process and principle of the zirconium oxide modified activated carbon catalyzing potassium permanganate to capture the electrons of organic pollutants in the water phase are 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 The change of organic matter concentration can be determined.

[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[AC@ZrO 2 Catalytic potassium permanganate oxidation removal rate<!-- 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[AC@ZrO 2 Catalytic potassium permanganate oxidation removal rate]]> 0 0 0 5 minutes 4.1％ 21.5％ 10 minutes 23.60％ 62.70％

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

[0043] Application Example 2:

[0044] The AC@ZrO prepared in Example 1 2 and potassium permanganate at a mass ratio of 1:0.04 were added to simulated sewage, which contained 1.6 mg / L diclofenac. AC@ZrO 2 The concentration of potassium permanganate is 0.5 g / L, and the concentration of potassium permanganate is 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 changes in the removal rate of diclofenac over time are shown in Table 3.

[0045] Table 3

[0046] time Potassium permanganate oxidation removal rate <![CDATA[AC@ZrO 2 Catalytic potassium permanganate oxidation removal rate]]> 0 0 0 5 minutes 8.53％ 89.08％ 10 minutes 21.30％ 91.25％

[0047] Application Example 3:

[0048] The AC@ZrO prepared in Example 1 2 and potassium permanganate at a mass ratio of 1:0.1 were added to simulated sewage, which contained 1.6 mg / L diclofenac. AC@ZrO 2 The concentration of potassium permanganate is 0.5 g / L, and the concentration of potassium permanganate is 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 changes in the removal rate of diclofenac over time are shown in Table 4.

[0049] Table 4

[0050] time Potassium permanganate oxidation removal rate <![CDATA[AC@ZrO 2 Catalytic potassium permanganate oxidation removal rate]]> 0 0 0 2 minutes 17.90％ 82.3％ 5 minutes 31.80％ 88.4％

[0051] From the data in Tables 1 to 4, we can see that when AC@ZrO 2 When the mass ratio of diclofenac 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] The AC@ZrO prepared in Example 1 2 The AC@ZrO 2The concentration of potassium permanganate is 0.5g / L, and the concentration of potassium permanganate is 0.01g / L. Ordinary potassium permanganate was used as a control group, and potassium permanganate (0.01g / L) was added to the same volume of sewage. The pH of the sewage was 5. The changes in the removal rate of phenol over time are shown in Table 5.

[0054] Table 5

[0055] time Potassium permanganate oxidation removal rate <![CDATA[AC@ZrO 2 Catalytic potassium permanganate oxidation removal rate]]> 0 0 0 20 minutes 5.30％ 19.20％ 40 minutes 12.00％ 41.80％

[0056] Comparative Example 1:

[0057] The AC@ZrO prepared in Example 1 2 The AC@ZrO 2 The concentration of atrazine 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 changes in the removal rate of atrazine over time are shown in Table 6.

[0058] Table 6

[0059] time Potassium permanganate oxidation removal rate <![CDATA[AC@ZrO 2 Catalytic potassium permanganate oxidation removal rate]]> 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] The zirconium oxide (ZrO 2 ) and potassium permanganate were added into 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[ZrO 2 Catalytic potassium permanganate oxidation removal rate]]> 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 effect of activated carbon or zirconium oxide alone in catalyzing the degradation of diclofenac with potassium permanganate is not ideal. 2 —KMnO 4 *—Active complexes of organic pollutants are an indispensable step in degrading organic pollutants and are also the AC@ZrO mentioned in this invention. 2 The key mechanism of catalytic degradation of diclofenac by potassium permanganate.

[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. Application of zirconium oxide modified activated carbon in catalytic potassium permanganate deep treatment of sewage, 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; When in use, AC@ZrO2 and potassium permanganate are added to the sewage to be treated at a mass ratio of 1:0.01-0.1, so that the pollutants in the sewage can be effectively treated; the pollutants are phenolic organic pollutants.

2. The use 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 use according to claim 1, characterized in that: The mass fraction of the ammonia solution in step (2) is 25-35wt%.

4. The use 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. The use according to claim 1, characterized in that: The sewage to be treated includes wastewater from the effluent of a sewage treatment plant from which pollutants have not yet been removed.

6. The use according to claim 1, characterized in that: The concentration range of the phenolic organic pollutants is 0.01-100 mg / L.

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