阅读说明：本技术 一种三维铁锰复合电极去除水中五价锑污染物的方法 (Method for removing pentavalent antimony pollutants in water by using three-dimensional iron-manganese composite electrode ) 是由 周永潮 郑雯昕 张仪萍 张土乔 于 2021-07-21 设计创作，主要内容包括：本发明涉及废水处理技术领域,具体涉及一种三维铁锰复合电极去除水中五价锑污染物的方法,包括如下步骤：将铁、锰颗粒混合作为阳极、铁板作为阴极制备电絮凝反应器,处理含五价锑污染物的废水。本发明利用三维铁锰复合电极强化电絮凝效果去除水中五价锑污染物的方法,该方法简化药品的投加环节,降低处理成本,且能有效的去除废水中的五价锑污染物。同时在反应后溶液中铁锰的含量也很低,无二次污染的危害,非常适合工业推广应用。(The invention relates to the technical field of wastewater treatment, in particular to a method for removing pentavalent antimony pollutants in water by using a three-dimensional ferro-manganese composite electrode, which comprises the following steps: iron and manganese particles are mixed to be used as an anode, and an iron plate is used as a cathode to prepare an electric flocculation reactor for treating the wastewater containing pentavalent antimony pollutants. The method for removing the pentavalent antimony pollutants in the water by using the three-dimensional iron-manganese composite electrode to strengthen the electrocoagulation effect simplifies the adding link of the medicament, reduces the treatment cost and can effectively remove the pentavalent antimony pollutants in the wastewater. Meanwhile, the content of iron and manganese in the solution after the reaction is very low, no secondary pollution is caused, and the method is very suitable for industrial popularization and application.)

1. A method for removing pentavalent antimony pollutants in water by using a three-dimensional ferro-manganese composite electrode is characterized by comprising the following steps: iron and manganese particles are mixed to be used as an anode, and an iron plate is used as a cathode to prepare an electric flocculation reactor for treating the wastewater containing pentavalent antimony pollutants.

2. The method for removing pentavalent antimony pollutants in water by using the three-dimensional ferro-manganese composite electrode according to claim 1, wherein the volume ratio of iron to manganese is 7: 3-19: 1.

3. The method for removing pentavalent antimony pollutants in water by using the three-dimensional ferro-manganese composite electrode according to claim 1, wherein the volume ratio of iron to manganese is 7: 3-5: 1.

4. The method for removing pentavalent antimony pollutants in water by using the three-dimensional ferro-manganese composite electrode according to claim 1, wherein the particle sizes of iron and manganese particles are both 20-50 cm.

5. The method for removing pentavalent antimony pollutants in water by using the three-dimensional ferro-manganese composite electrode according to claim 1, wherein the applied current is 0.20-0.35A when the electric flocculation reactor is used for treating wastewater.

6. The method for removing pentavalent antimony pollutants in water by using the three-dimensional ferro-manganese composite electrode according to claim 1, wherein when the electric flocculation reactor is used for treating wastewater, the hydraulic retention time is more than 30 min.

7. The method for removing pentavalent antimony pollutants in water by using the three-dimensional ferro-manganese composite electrode according to claim 1, wherein when the electric flocculation reactor is used for treating wastewater, the hydraulic retention time is 60-90 min.

8. The method for removing pentavalent antimony pollutants in water by using the three-dimensional ferro-manganese composite electrode according to claim 1, wherein the distance between the anode and the cathode is 0.5-2 cm.

Technical Field

The invention relates to the technical field of wastewater treatment, in particular to a method for removing pentavalent antimony pollutants in water by using a three-dimensional iron-manganese composite electrode.

Background

In recent years, the problem of heavy metal antimony in the printing and dyeing industry becomes a new challenge in pollution prevention and control. As a catalyst commonly used in the production process of polyester fiber (namely, polyester industrial yarn) which is a raw material in the textile industry, antimony compounds often remain in the polyester fabric and are released in a large amount in the subsequent process. Studies have shown that antimony and its compounds have slow, acute toxicity and carcinogenicity to organisms, and are listed by various countries as the category of priority for controlling pollutants. At present, the common methods for removing antimony pollutants in water include a chemical precipitation method, an adsorption method, an ion exchange method and the like. Compared with trivalent antimony, pentavalent antimony has large electronegativity and high solubility, and is more difficult to remove.

The electric flocculation technology is a hot spot in the research field of recent water treatment, and the electric flocculation technology refers to that under the action of an external electric field, an electrode generates electrochemical reaction. The metal anode generates cations with flocculation property, and is hydrolyzed and polymerized in solution to form a series of hydroxides or polynuclear hydroxyl complexes, antimony pollutants are removed through adsorption, coprecipitation and air flotation, and the currently commonly used electrode materials comprise two types of iron and aluminum, and most of the materials are plate-shaped or rod-shaped.

Some scholars have focused on the effect of the way the electrodes are combined on the structure of the floes. The result shows that the combined use of the aluminum and iron electrodes can improve the removal efficiency, and the electroflocculation product has better crystallization state. Researchers add manganese sulfate or manganese chloride solution into the antimony-containing wastewater to obtain a good antimony removal effect. But the additional dosing increases the operation difficulty and increases the removal cost.

CN 106746058A discloses a method for removing pentavalent antimony in wastewater, wherein the advantages of electrochemical treatment are combined, pentavalent antimony is reduced to trivalent or even partially to zero-valent antimony by using a working electrode, and antimony-containing compounds in the wastewater are further removed by using ferric chloride as a flocculating agent by using a coagulation method.

Also, CN 104724797 a discloses a method for removing pentavalent antimony pollutants in water by manganese ion enhanced electrochemistry, which utilizes a cation dissolution method to generate ferrous and ferric ions, combines with the added manganese ions to effectively reduce the pentavalent antimony pollutants, and generates manganese dioxide to enhance the electrocoagulation action, thereby effectively removing the antimony pollutants in water.

However, such a process is affected by the degree of reduction of pentavalent antimony on the one hand and the addition of flocculants also increases the cost on the other hand.

Disclosure of Invention

Aiming at the problems that the method for removing the pentavalent antimony pollutants in the wastewater in the prior art is not ideal in effect, needs to add a flocculating agent and is high in cost, the invention provides the method for removing the pentavalent antimony pollutants in the wastewater by utilizing the three-dimensional iron-manganese composite electrode to strengthen the electric flocculation effect.

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

a method for removing pentavalent antimony pollutants in water by using a three-dimensional ferro-manganese composite electrode comprises the following steps:

iron and manganese particles are mixed to be used as an anode, an iron plate is used as a cathode to be used for preparing an electric flocculation reactor, and wastewater containing pentavalent antimony pollutants is treated.

The starting principle of the invention is as follows: under the condition of electrifying, the ferro-manganese composite electrode prepared by utilizing the iron and manganese particles generates three-dimensional ferro-manganese double hydroxide flocs with amphoteric surface hydroxyl groups, has the advantages of large specific surface area, large adsorption capacity and the like, and can effectively adsorb antimony pollutants. Meanwhile, compared with the traditional electrode form, the three-dimensional porous medium electrode can enable the electrode material to have a larger contact area with water flow, and the yield of the electroflocculation product is improved. Promote the frequency of the effective collision of floc, increase the floc particle size, reinforcing electric flocculation to effectual aquatic antimony pollutant of getting rid of, the floc of production simultaneously easily air supporting can be favorable to high-efficient solid-liquid separation, improves the get rid of efficiency of antimony pollutant.

The inventor finds that the anode mixed with iron and manganese particles has a strong adsorption effect and is convenient for collecting and removing generated flocs.

Wherein the volume ratio of the iron particles to the manganese particles is 7: 3-19: 1, preferably the volume ratio of the iron particles to the manganese particles is 7: 3-5: 1, and most preferably the volume ratio of the iron particles to the manganese particles is 8: 2, the specific surface area of the flocculating constituent is the largest, and the removal efficiency is the highest.

Preferably, the particle size of the iron and manganese particles is 20-50 cm.

When the electric flocculation reactor is used for treating wastewater, the applied current is 0.20-0.35A. Below 0.20A will result in insufficient removal and too high a current will cause unnecessary power losses.

When the electric flocculation reactor is used for treating wastewater, the hydraulic retention time is more than 30min, and the removal is insufficient when the hydraulic retention time is less than 30 min.

Preferably, when the electric flocculation reactor is used for treating wastewater, the hydraulic retention time is 60-90 min, the removal time is too long, the electrolysis time is too long, and excessive metal ions are generated to cause secondary pollution.

The distance between the anode and the cathode is 0.5-2 cm, preferably 1 cm.

When the volume of the wastewater containing antimony pollutants to be treated is 2L, the volume of the anode is at least 260 mL.

Compared with the prior art, the invention has the following beneficial effects:

the method of the invention does not need to add any flocculating agent, the cost for removing the antimony-containing pollutant is reduced, the pentavalent antimony does not need to be reduced into the trivalent antimony pollutant in the treatment process, and the treatment effect is not influenced by the reduction degree; the floc in the method is easy to float air and has the characteristic of high-efficiency solid-liquid separation. And on one hand, the removal efficiency of pollutants such as pentavalent antimony and the like can be effectively improved through the action of the ferro-manganese composite electrode, and meanwhile, the ferro-manganese content in the solution after reaction is low, so that the method is free from secondary pollution hazards, and is very suitable for industrial popularization and application.

Drawings

FIG. 1 is a graph showing the removal rate of antimony contaminants as a function of time for example 1 and comparative example 1.

FIG. 2 is SEM scanning electron micrographs of iron-manganese composite double hydroxide flocs of example 1 and iron flocs of comparative example 1; wherein (a) is a ferro-manganese composite double hydroxide floc; (b) the iron flocs are granular.

FIG. 3 is a graph of antimony contaminant removal rate over time for different current densities for example 2.

FIG. 4 is a graph of antimony contaminant removal rate over time for different iron-manganese ratios in example 3.

FIG. 5 is a graph of antimony contaminant removal rate over time for different iron-manganese ratios in example 4.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Those skilled in the art should understand that they can make modifications and equivalents without departing from the spirit and scope of the present invention, and all such modifications and equivalents are intended to be included within the scope of the present invention.

Example 1

In the electrochemical reactor, iron and manganese particles are mixed to serve as an anode and an iron plate serves as a cathode. And (2) supplying power by adopting a direct current power supply, wherein the current density is 0.35A, and the volume ratio of iron to manganese is 8: 2, the volume ratio of the anode to the water to be treated is 260ml/2L, and the distance between the polar plates is 1 cm. Preparing the antimony-containing wastewater, wherein the concentration of pentavalent antimony is 1mg/L, adjusting the pH value of the water to 6.5, pumping the water to be treated into an electrochemical reactor, switching on a power supply, and starting reaction. When the treatment time is 60 minutes, the removal rate of antimony reaches 95.19%, and when the treatment time is 90 minutes, the removal rate of antimony reaches 98.74%.

Comparative example 1

The three-dimensional iron electrode is prepared by adopting iron particles and used as an anode to replace the iron-manganese composite electrode in the example 1, other conditions are the same as those in the example 1, and the treatment effect of the pentavalent antimony pollutant in the wastewater is tested. When the treatment time is 60 minutes, the removal rate of antimony reaches 81.8%, and when the treatment time is 90 minutes, the removal rate of antimony reaches 94.45%.

The removal of antimony contaminants by example 1 and comparative example 1 is compared as shown in figure 1.

Microscopic observation is carried out on the ferro-manganese composite double hydroxide floc prepared in the example 1 and the ferro-manganese floc prepared in the comparative example 1, and the SEM scanning result is shown in figure 2, wherein (a) is the ferro-manganese composite double hydroxide floc which has a hexagonal sheet structure, a larger specific surface area and more surface active adsorption points; and the iron flocs in the step (b) are granular, are precisely stacked and have small specific surface area, which is also the main reason for the difference of the antimony pollutant removal effects of the iron flocs and the antimony pollutant removal effects of the iron flocs. And when the reaction time is the same in the experimental process, the ferro-manganese electrode is used, the solution in the reactor is observed to be clear, the scum layer on the surface is obviously thick, and the air flotation effect is good and the separation capacity is strong.

Example 2

In the electrochemical reactor, iron and manganese particles are mixed to serve as an anode and an iron plate serves as a cathode. A direct current power supply is adopted for supplying power, four control groups are set in the experiment, the current density is 0.20A, 0.25A, 0.30A and 0.35A respectively, the volume ratio of the anode to the water to be treated is 260ml/2L, and the distance between the polar plates is 1 cm. Preparing the antimony-containing wastewater, wherein the concentration of pentavalent antimony is 1mg/L, adjusting the pH value of the water to 6.5, pumping the water to be treated into an electrochemical reactor, switching on a power supply, and starting reaction. As a result, as shown in FIG. 3, when the treatment time was 60 minutes, the antimony removal rate was the lowest at 76.24% at a current density of 0.20A, and the antimony removal rate was the highest at 95.19% at a current density of 0.35A; when the treatment time was 90 minutes, the antimony removal rate was the lowest at 80.98% at a current density of 0.20A, and the antimony removal rate was the highest at 98.74% at a current density of 0.35A. It can be seen that the removal efficiency of antimony contaminants is low when the current density is too low, but the removal efficiency of antimony contaminants is not ideal when the current density is too high.

Example 3

In the electrochemical reactor, iron and manganese particles are mixed to serve as an anode and an iron plate serves as a cathode. A direct-current power supply is adopted for supplying power, four control groups are set in the experiment, and the volume ratio of iron to manganese is 7: 3; 8: 2; 9: 1; 19:1, the volume ratio of the anode to the water to be treated is 260ml/2L, the current density is 0.35A, and the distance between the polar plates is 1 cm. Preparing the antimony-containing wastewater, wherein the concentration of pentavalent antimony is 1mg/L, adjusting the pH value of the water to 6.5, pumping the water to be treated into an electrochemical reactor, switching on a power supply, and starting reaction. As shown in FIG. 4, the antimony removal rate was the lowest at 90.03% when the volume ratio of Fe to Mn was 7:3, the highest at 95.19% when the volume ratio of Fe to Mn was 8:2, the lowest at 96.76% when the volume ratio of Fe to Mn was 19:1, and the highest at 98.74% when the volume ratio of Fe to Mn was 8:2, when the treatment time was 90 minutes, at 60 minutes. In summary, when the content of iron is gradually increased, the removal efficiency of antimony pollutants is increased and then decreased, so that the ratio of the two is controlled in the optimal range, and the best antimony pollutant treatment effect can be obtained.

Example 4

In order to verify that the adsorption effect of the iron-manganese flocs is stronger than that of the iron flocs, the flocs are collected centrifugally after the reaction is finished under different iron-manganese ratios in example 3, and then a reabsorption experiment is carried out. 1g of flocs was added to 100ml of wastewater having an initial Sb (V) concentration of 1mg/L and a ph of 6.5, and the mixture was stirred by a magnetic stirrer rotating at 500r/min to uniformly disperse the flocs in a beaker, and the change of the removal rate with time is shown in FIG. 5. The iron-manganese mixed system can be obviously seen, wherein the efficiency of antimony pollutants is far higher than that of an iron system, the specific data is also shown in table 1, after 1 hour of adsorption, the removal rate of iron-manganese flocs is more than 60%, and the removal rate of iron flocs is only 20.87%.

TABLE 1 removal rate of antimony contaminants at different Fe-Mn ratios