A water treatment antimony removal agent and its preparation method

Abstract

The present invention relates to the technical field of water treatment, in particular to a water treatment antimony removal agent and a preparation method thereof, which helps the antimony-containing wastewater in the printing and dyeing industry to achieve up-to-standard discharge and meet the antimony discharge standard in the "Discharge Standard of Water Pollutants for the Textile Dyeing and Finishing Industry" (GB4287-2012); a water treatment antimony removal agent is prepared from the following raw materials: polymeric ferric sulfate and sodium bisulfite.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and particularly to a water treatment antimony removal agent and a preparation method thereof. Background Art

[0002] Antimony pollution is the pollution of the environment by antimony and its compounds. When smelting antimony and antimony-containing metals or mining coal mines, and when using antimony or its compounds in other processes, pollutants containing antimony elements or their compounds can be produced to pollute the environment. Antimony in water comes from the dissolution of antimony-containing rocks, the discharge of antimony-containing industrial wastewater, and antimony-containing rainfall, etc. Water seeping into the soil also pollutes it, causing antimony to accumulate in water. When it reaches 3×10 -6 mg / l, it begins to be toxic to algae, and when it reaches 12×10 -6 mg / l, it is toxic to fish. The average antimony content in the human body is 5.8 milligrams, mostly from tableware, ceramic glazes, etc. Workers engaged in antimony mining and smelting are prone to antimony poisoning. About half of the people exposed to antimony trioxide (Sb2O3) have heart disorders. Antimony is similar to arsenic, and the toxicity of trivalent antimony is greater than that of pentavalent antimony. Antimony hydride (SbH3) is extremely toxic and can cause hemolysis, liver and kidney disorders, and pulmonary edema after inhalation.

[0003] Antimony compounds have a wide range of applications. Taking textile printing and dyeing where a water treatment antimony removal agent is applied as an example, when synthesizing polyester fiber, the raw material of polyester, antimony-containing catalysts such as antimony acetate and antimony glycol are required for the synthesis of terephthalic acid and ethylene glycol. It is the most efficient and economical catalyst at present and can almost help achieve a conversion rate of 100%. However, during the synthesis process, antimony elements will be evenly dispersed into the polyester fiber in a free state. When these fibers enter the printing and dyeing factory or the weaving factory for further processing, in the desizing and alkali weight reduction processes, the free antimony will enter the wastewater and deposit. Since the "Discharge Standard of Water Pollutants for the Textile Dyeing and Finishing Industry" (GB4287-2012) requires the limit index of metallic antimony to be 100 μg / L, and after the accumulation of antimony in printing and dyeing and spraying wastewater layer by layer, it may eventually exceed the standard. At present, the control of heavy metal antimony can only rely on traditional flocculants for dosing treatment, and the treatment effect of traditional agents on antimony is very limited. Therefore, how to effectively remove antimony deposited in wastewater has become a problem that needs to be solved. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a water treatment antimony removal agent, which helps the antimony-containing wastewater in the printing and dyeing industry to meet the discharge standard and meet the antimony discharge standard in the "Discharge Standard of Water Pollutants for the Textile Dyeing and Finishing Industry" (GB4287-2012).

[0005] The present invention also provides a preparation method of the water treatment antimony removal agent. The method is simple and easy to operate, and the prepared water treatment antimony removal agent has the advantage of high antimony removal rate.

[0006] A water treatment antimony removal agent of the present invention comprises the following raw materials: polyferric sulfate and sodium bisulfite.

[0007] Furthermore, it also includes water.

[0008] Furthermore, the raw materials are mixed evenly to obtain the water treatment antimony removal agent.

[0009] A method for treating antimony-containing wastewater of the present invention comprises the following steps: adding the water treatment antimony removal agent to the wastewater, mixing evenly, precipitating polyferric sulfate antimony compound precipitate, and then separating the solid from the liquid.

[0010] A method for treating antimony-containing wastewater of the present invention further comprises a step of adjusting the pH of the wastewater before adding the water treatment antimony removal agent to the wastewater.

[0011] A method for treating antimony-containing wastewater of the present invention adjusts the pH of the wastewater to 7 - 7.5.

[0012] A method for treating antimony-containing wastewater of the present invention, the addition amount of the water treatment antimony removal agent is greater than or equal to 1‰ of the weight of the antimony-containing wastewater.

[0013] A method for treating antimony-containing wastewater of the present invention further adds a polymer to the wastewater.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: A water treatment antimony removal agent provided by the present invention uses polyferric sulfate and sodium bisulfite as raw materials. Sodium bisulfite, as a reducing agent, can directly reduce antimony ions to form antimony precipitate and also reduce pentavalent antimony to trivalent antimony. It is easier to capture trivalent antimony ions through polyferric sulfate and react with them to form polyferric sulfate antimony compound precipitate. The antimony removal rate in the wastewater is as high as over 90%;

[0015] The preparation method of the antimony removal agent provided by the present invention is simple and feasible. The prepared antimony removal agent has the advantage of high antimony removal rate. Applying the above antimony removal agent to the treatment of antimony-containing wastewater can effectively reduce the antimony content in the wastewater, and the antimony removal rate is as high as over 90%. Specific Embodiments

[0016] The following combines examples to further describe in detail the specific embodiments of the present invention. The following examples are used to illustrate the present invention, but not to limit the scope of the present invention.

[0017] In the first aspect, the present invention provides a water treatment antimony removal agent prepared from the following raw materials: polyferric sulfate and sodium bisulfite.

[0018] Polyferric sulfate is an inorganic polymer flocculant with excellent performance. Its morphological property is light yellow amorphous powdery solid, which is extremely soluble in water. Sodium bisulfite has strong reducibility and also has the function of sterilization and disinfection.

[0019] At present, some technologies directly use polyferric sulfate to remove antimony from wastewater. Since there is only a small amount of antimony in a large amount of printing and dyeing wastewater and it exists in different valence forms, simply using polyferric sulfate to remove it does not cover all cases. Therefore, although antimony can be removed, the removal effect is not good, and a large amount of polyferric sulfate is needed to achieve effective removal, which is not suitable for industrial application. During actual treatment, high-concentration antimony-containing wastewater also needs to be separated for separate treatment of different qualities, and the process flow is relatively cumbersome.

[0020] The weight ratio of polyferric sulfate to sodium bisulfite is 10:1. Through a large number of experiments, it is proved that when the weight ratio of polyferric sulfate to sodium bisulfite is 10:1, the removal effect of antimony is the best and the economic cost is also the lowest. In the present invention, the weight ratio of polyferric sulfate to sodium bisulfite can also be: 5:1, 15:1, 20:1, etc.

[0021] Secondly, the present invention provides a preparation method of the above-mentioned water treatment antimony remover. Mixing the raw materials evenly can obtain the antimony remover. The above method is simple and easy to implement, and the prepared antimony remover has the advantage of high antimony removal rate. Further, water is also included in the raw materials. Water is mainly used to dissolve polyferric sulfate and sodium bisulfite, making them in a liquid state before being put into the wastewater, so that it is not necessary to wait for them to dissolve during wastewater treatment, reducing the treatment time.

[0022] Thirdly, the present invention provides a method for treating antimony-containing wastewater. The treatment of antimony-containing wastewater includes the following steps: adding the above-mentioned water treatment antimony remover and polymer to the wastewater with adjusted pH, mixing evenly and then precipitating, and then separating the solid from the liquid. The treatment of the above-mentioned antimony-containing wastewater is very simple, with a short treatment time and high efficiency. The mixing time is only 30 s to 1 min, the time for complete precipitation is within 15 min, and the antimony removal rate is above 90%.

[0023] In a preferred embodiment, before adding the above-mentioned water treatment antimony remover, there is also a step of adjusting the pH of the wastewater. When the pH of the wastewater is alkaline, it is easier to precipitate, and the precipitated antimony sulfate will exist stably in the form of basic antimony sulfate.

[0024] In a preferred embodiment, the pH of the wastewater is adjusted to 7 - 7.5. It has been proven through experiments that when the pH of the wastewater is around 7.5, good removal effects can be achieved. If the pH is too low, the removal effect of antimony is not good. If the pH is too high, it will increase the subsequent treatment process of the wastewater and the economic efficiency is low. The present invention fully considers the dual effects of the antimony removal rate and the wastewater treatment cost, and determines that when the pH of the wastewater is around 7.5, the antimony removal rate is the highest and the wastewater treatment cost is relatively low.

[0025] In a preferred embodiment, the dosage of the antimony removal agent is at least 1‰ of the weight of the antimony-containing wastewater. The minimum dosage of the water treatment antimony removal agent of the present invention is 1‰ (weight content) of the antimony-containing wastewater to achieve good removal effects. If it is too low, antimony cannot be effectively removed. If the dosage of the antimony removal agent is too much, the economic efficiency is low.

[0026] The present invention will be further described in detail below with reference to examples, comparative examples and test examples;

[0027] In the following examples, comparative examples and test examples, the polymer is all polyacrylamide;

[0028] The water treatment antimony removal agent of the present invention and the water treatment antimony removal agent in the prior art are used to treat the wastewater according to the above treatment method for antimony-containing wastewater, and the following data are obtained:

[0029] Example 1

[0030] Specimen Adjust the pH Antimony removal agent for water treatment Polymer Antimony content after treatment Removal rate Raw water 7 1‰ 0.1‰ 0.086 96％ Raw water 7.5 1‰ 0.1‰ 0.062 97％

[0031] In Example 1, the raw materials of the water treatment antimony removal agent are polyferric sulfate and sodium bisulfite, and the weight ratio is 15:1;

[0032] Comparative Example 1 (the water treatment antimony removal agent is polyferric sulfate)

[0033] Specimen Adjust the pH Antimony removal agent for water treatment Polymer Antimony content after treatment Removal rate Raw water 7 1‰ 0.1‰ 0.76 62％ Raw water 7.5 1‰ 0.1‰ 0.66 67％

[0034] Comparative Example 2 (the water treatment antimony removal agent is polyaluminum chloride)

[0035] Specimen Adjust the pH Antimony removal agent for water treatment Polymer Antimony content after treatment Removal rate Raw water 7 1‰ 0.1‰ 1.5 25％ Raw water 7.5 1‰ 0.1‰ 1.4 30％

[0036] Comparative Example 3 (the weight ratio of polyaluminum ferric sulfate and sodium bisulfite is 15:1)

[0037] Specimen Adjust the pH Antimony removal agent for water treatment Polymer Antimony content after treatment Removal rate Raw water 7 1‰ 0.1‰ 0.61 70％ Raw water 7.5 1‰ 0.1‰ 0.55 73％

[0038] As can be seen from the table treatment results, when the same amount of reagent is added, the antimony content in the wastewater treated by the antimony removal agent in Example 1 is significantly lower than that in the wastewater treated by the antimony removal agents in Comparative Examples 1-3. This shows that the antimony removal agent in Example 1 has a good removal effect on heavy metal antimony in the wastewater. For example, when the reagent addition amount is 1‰, the removal rate of Example 1 is 96-97%, while the removal rates of Comparative Examples 1-3 are all below 75%.

[0039] Therefore, the raw materials of the antimony removal agent of the present invention are reasonably selected, and the synergistic cooperation of polyferric sulfate and sodium bisulfite is fully exerted. It can directly reduce antimony ions to form antimony precipitation and also reduce pentavalent antimony to trivalent antimony. It is easier to capture trivalent antimony ions through polyferric sulfate and react with them to form polyferric sulfate-antimony compound precipitation, achieving a good antimony removal effect and meeting the needs of practical applications. However, no matter using polyferric sulfate, polyaluminum chloride, or a mixture of polyaluminum ferric sulfate and potassium permanganate, the removal effect of the antimony removal agent of the present invention cannot be achieved. Even when the reagent addition amount reaches 1‰, the antimony content in the treated wastewater is still above 0.1 mg / L and cannot be directly discharged, and further treatment is required, so the practical application value is very low.

[0040] At the same time, the precipitation time of Example 1 is 15 min, while the precipitation time of Comparative Examples 1-3 is about 30 min. The time used in Example 1 is shorter. Therefore, the antimony removal agent of the present invention removes heavy metal antimony more quickly, effectively saving time costs.

[0041] Example 2: (The weight ratio of polyferric sulfate to sodium bisulfite is 5:1)

[0042] Specimen Adjust the pH Antimony removal agent for water treatment Polymer Antimony content after treatment Removal rate Raw water 7 1‰ 0.1‰ 0.12 94％ Raw water 7.5 2‰ 0.1‰ 0.11 95％

[0043] Example 3: (The weight ratio of polyferric sulfate to sodium bisulfite is 10:1)

[0044] Specimen Adjust the pH Antimony removal agent for water treatment Polymer Antimony content after treatment Removal rate Raw water 7 1‰ 0.1‰ 0.045 98％ Raw water 7.5 2‰ 0.1‰ 0.022 99％

[0045] Example 4: (The weight ratio of polyferric sulfate to sodium bisulfite is 20:1)

[0046] Specimen Adjust the pH Antimony removal agent for water treatment Polymer Antimony content after treatment Removal rate Raw water 7 1‰ 0.1‰ 0.081 96％ Raw water 7.5 2‰ 0.1‰ 0.072 96％

[0047] The antimony removal agents in Examples 1, 2 and 4 are composed of non-preferred formulations of the present invention. Among them, the proportion of sodium bisulfite in the formulation of Example 2 is higher than that in the preferred formulation, while the proportions of sodium bisulfite in Examples 1 and 4 are lower than that in the preferred formulation. The antimony removal agent in Example 3 is composed of the preferred formulation of the present invention. From the treatment results, it can be seen that when the dosage of the agent is the same, the antimony content in the wastewater treated with the antimony removal agent of Example 3 is higher than that of Examples 1, 2 and 4. Further, in the case of pH 7.5 and increasing the dosage of the water treatment antimony removal agent, the removal efficiency can be further improved. Of course, in the actual application process, economic benefits need to be considered while meeting the standards. Therefore, the antimony removal agent obtained by using the preferred formulation of the present invention can give full play to the comprehensive advantages of polyferric sulfate and sodium bisulfite, and can effectively avoid the reduction of antimony removal rate caused by too high or too low content of sodium bisulfite; and when the ratio of polyferric sulfate to sodium bisulfite is 10:1, the antimony removal effect is the best and the economic cost is the lowest.

[0048] In addition to the above application tests, the present invention also treated the antimony-containing wastewater of a certain printing and dyeing company in Suzhou with the water treatment antimony removal agents of Example 3 and Comparative Example 2 respectively. The pH of the raw water was 6.5 and the antimony content was 0.354 mg / L. The following are the treatment results:

[0049] Test Example 1 (Polyferric Sulfate and Sodium Bisulfite in Example 1 at 10:1)

[0050] Specimen Adjust the pH Antimony removal agent for water treatment Polymer Antimony content after treatment Removal rate Raw water 7 1‰ 0.1‰ 0.0106 97％ Raw water 7.5 1‰ 0.1‰ 0.0035 99％

[0051] Test Example 2 (Polyaluminum Chloride in Comparative Example 2)

[0052] Specimen Adjust the pH Antimony removal agent for water treatment Polymer Antimony content after treatment Removal rate Raw water 7 1‰ 0.1‰ 0.25 29％ Raw water 7.5 1‰ 0.1‰ 0.22 38％

[0053] It can be seen from the results that the antimony removal agent in Example 1 has a better antimony removal effect on heavy metal antimony in the wastewater. When the dosage of the water treatment antimony removal agent is 1‰, the removal rate in Example 1 is 99%, while the removal rate in Comparative Example 2 is only 38%. Therefore, the antimony removal rate of the antimony removal agent of the present invention is high, while the antimony removal effect of using a single polyaluminum chloride on the antimony in the wastewater is extremely unsatisfactory.

[0054] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for treating antimony-containing wastewater, characterized in that, It includes the following steps: Adjust the pH of the antimony-containing wastewater to 7-7.5, and then add a water treatment antimony removal agent and a high molecular organic matter to the antimony-containing wastewater. The water treatment antimony removal agent includes polyferric sulfate and sodium bisulfite; after mixing evenly, a polyferric sulfate antimony compound precipitate is precipitated, and then solid-liquid separation is carried out.

2. The method for treating antimony-containing wastewater according to claim 1, wherein, Mix polyferric sulfate and sodium bisulfite evenly to obtain the water treatment antimony removal agent.

3. The treatment method of antimony-containing wastewater according to claim 1, characterized in that, The addition amount of the water treatment antimony removal agent is greater than or equal to 1‰ of the weight of the antimony-containing wastewater.