A method for treating potassium permanganate wastewater

Abstract

The invention discloses a method for disposing potassium permanganate wastewater, comprising the following steps: adding acid to potassium permanganate wastewater to adjust the pH value of the solution to 2‑3, adding a discarded reducing agent at a rate of less than 10 g / min until the potassium permanganate wastewater fades and becomes colorless; the discarded reducing agent is discarded potassium borohydride or sodium borohydride. The inventive method is simple, easy to operate, saves medicaments, and disposes of discarded potassium borohydride, sodium borohydride, and waste acid while disposing of potassium permanganate wastewater, rationally utilizes resources, saves costs, is safe and efficient, improves production capacity, and achieves the purpose of waste coordinated disposal and waste treatment, with good economic benefits.

Description

Technical Field

[0001] The invention belongs to the technical field of harmless treatment of hazardous wastes, and particularly relates to a method for treating potassium permanganate wastewater. Background Art

[0002] Potassium permanganate is a strong oxidant. It is black-purple crystal with a blue metallic luster and is odorless. It is prone to explosion when in contact with certain organic matter or oxidizable substances. It is soluble in water and alkali solution, and slightly soluble in methanol, acetone, and sulfuric acid. The manganese ion in potassium permanganate is in the highest valence state of +7, and can undergo redox reactions with substances with very weak reducing properties. Therefore, it is a strong oxidant. It can explode when it encounters concentrated sulfuric acid and ammonium salts, and is listed in the "List of Dangerous Chemicals that Can Be Exploded". Potassium permanganate wastewater is common in medical, industrial and other industries, and has a disinfecting and sterilizing effect. The potassium permanganate wastewater produced in industry has a high concentration and a large output. It has strong oxidizing properties and a darker color. It is corrosive and polluting to the environment when used directly for disinfection and sterilization. This type of method has a slow disposal speed and low production capacity.

[0003] Potassium borohydride and sodium borohydride are inorganic compounds with strong hygroscopicity. They can cause combustion when in contact with water, humid air, acids, oxidants, high heat and open flames. Structurally, the tetrahydroboron anion of sodium borohydride has a tetrahedral structure centered on the boron atom, and the hydrogen atoms are at the four vertices of the tetrahedron. It may release hydrogen anions that are very alkaline and have strong nucleophilicity. It is usually used as a foaming agent in industry and as a hydrogenating agent in the pharmaceutical industry. It is also included in the "List of Dangerous Chemicals that Can Be Exploded and Prepared" and is controlled in accordance with the "Regulations on the Public Security Administration of Dangerous Chemicals that Can Be Exploded and Prepared". However, the discarded sodium borohydride and potassium borohydride contain some impurities, which makes it difficult to comprehensively utilize them after purification, and their strong reducibility increases the risk of temporary storage. There is currently no relevant technical literature available for reference on the harmless disposal of discarded sodium borohydride and potassium borohydride.

[0004] Therefore, it is of great application prospect to study a technology for simultaneously treating potassium permanganate wastewater and waste potassium borohydride, sodium borohydride and waste acid to achieve rational utilization of resources, save costs, treat waste with waste and realize resource disposal of waste. Summary of the invention

[0005] The invention aims to provide a method for treating potassium permanganate wastewater, which can treat waste potassium borohydride, sodium borohydride and waste acid while treating the potassium permanganate wastewater, thereby rationally utilizing resources and improving treatment efficiency.

[0006] The technical solution of the present invention is achieved in this way:

[0007] Under room temperature conditions, acid is added to potassium permanganate wastewater to adjust the pH value of the solution to 2-3, and waste reducing agent is added at a rate of less than 10 g / min until the potassium permanganate wastewater fades to colorless; the waste reducing agent is waste potassium borohydride or sodium borohydride. The waste reducing agent is added at a rate of less than 10 g / min. Since the waste reducing agent is a powdered solid or solid particle, it cannot be precisely controlled like a liquid. Instead, it is added in a manner that the amount added within 1 minute cannot be 10 g, and 10 g / min is an average value.

[0008] Preferably, the waste acid pH is less than 1, and the other heavy metal indicators are qualified.

[0009] Preferably, the pH of the solution after the waste acid is added is 2-3. Potassium permanganate has strong oxidizing properties under acidic conditions. The pH value is controlled at 2-3 to avoid excessive acid from producing highly toxic borane gas.

[0010] Preferably, after the reaction, the solution becomes colorless and transparent, and the pH value is 6-8.

[0011] Preferably, the potassium permanganate wastewater after treatment is non-oxidizing. The detection system is non-oxidizing using starch potassium iodide test paper. If the test paper does not turn blue, it proves that it is non-oxidizing. The reaction system is non-reducing using acidic potassium permanganate solution. If the acidic potassium permanganate solution does not fade, it proves that it is non-reducing.

[0012] The beneficial effects of the present invention are:

[0013] The applicant surprisingly found that when the pH value of potassium permanganate wastewater is 2-3, potassium borohydride and sodium borohydride are added at a rate of less than 10 g / min, and the potassium permanganate wastewater can completely react with potassium borohydride and sodium borohydride to eliminate their oxidizing properties and has no reducing properties. The generation of borane gas is avoided during the reaction process, and ultimately the safe disposal of potassium permanganate wastewater is achieved and the waste potassium borohydride and sodium borohydride are disposed of in coordination. When the pH of potassium permanganate wastewater is > 4, the reaction between potassium permanganate wastewater and potassium borohydride and sodium borohydride is incomplete. When the pH of the solution after the reaction is 6-8, it is still dark brown and has oxidizing and reducing properties. When the pH of potassium permanganate wastewater is < 2, acidic potassium permanganate wastewater reacts violently with potassium borohydride and sodium borohydride and releases highly toxic gas borane. When the pH of potassium permanganate wastewater is 2, potassium borohydride and sodium borohydride are added at a rate greater than 15g / min, acidic potassium permanganate wastewater reacts completely with potassium borohydride and sodium borohydride, but releases highly toxic gas borane.

[0014] The present invention has the following effects:

[0015] (1) The method is simple and easy to operate, which solves the problem of incomplete fading of potassium permanganate wastewater and will not cause secondary pollution to the equipment and the environment.

[0016] (2) Large-scale, rapid and safe disposal of potassium permanganate wastewater while co-disposing of waste potassium borohydride, sodium borohydride and waste acid.

[0017] (3) Rationally utilize resources, save costs, and improve production capacity. DETAILED DESCRIPTION

[0018] The present invention is further described in conjunction with examples. 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. It should be noted that in the present application, the mixed solution after the reaction in the production stage is tested for oxidizing properties using starch potassium iodide test paper, and the acid potassium permanganate solution is used to judge whether it is reducing properties. Heavy metal detection standards for production wastewater and waste acid: "Determination of Nickel in Water Quality by Flame Atomic Absorption Spectrophotometry" (GB 11912-89), "Determination of Copper, Zinc, Lead and Cadmium in Water Quality by Atomic Absorption Spectrophotometry" (GBT7475-1987), "Determination of Chromium in Water Quality by Flame Atomic Absorption Spectrophotometry" (HJ757-2015), "Determination of Mercury, Arsenic, Selenium, Bismuth and Antimony in Water Quality by Atomic Fluorescence Method" (HJ 694-2014).

[0019] Comparative Example 1

[0020] Under room temperature conditions, use an electronic balance to weigh 300g of potassium permanganate wastewater into a beaker, test the solution pH to be 6, add waste potassium borohydride at a rate of 5g / min, and stir while adding to ensure sufficient reaction (simultaneously use a portable hydrogen detector and a handheld borane gas detector for testing) until there is no obvious change in the mixed solution. After the reaction is complete, test the pH value, oxidizability, and reducibility of the mixed solution.

[0021] Test results and phenomena: Portable hydrogen detection test results (range: 0-1000ppm, alarm value set to 50ppm): 35ppm, no alarm;

[0022] The test results of the handheld borane gas detector (range: 0-100ppm, alarm value set to 10ppm): 0ppm, no alarm.

[0023] The mixed solution is dark brown, pH=7.25, starch potassium iodide test paper turns blue, and the solution after the reaction is dropped into acidic potassium permanganate solution to make the potassium permanganate solution fade; hydrogen is produced during the reaction, and the solution after the reaction still has oxidizing and reducing properties.

[0024] Comparative Example 2

[0025] Under normal temperature conditions, use an electronic balance to weigh 300g of potassium permanganate wastewater into a beaker, add sulfuric acid to adjust the pH value to 1, add potassium borohydride at a rate of 5g / min, and stir while adding to make the reaction complete (simultaneously use a portable hydrogen detector and a handheld borane gas detector for detection) until the mixed solution has no obvious changes. After the reaction is complete, test the pH value, oxidizing property, and reducing property of the mixed solution.

[0026] Test results and phenomena: Portable hydrogen detection test results (range: 0-1000ppm, alarm value set to 50ppm): 56ppm, sound, light and vibration alarm;

[0027] Test results of handheld borane gas detector (range: 0-100ppm, alarm value set to 10ppm): 20ppm, sound, light and vibration alarm;

[0028] The mixed solution is colorless and transparent, pH=7.95, starch potassium iodide test paper does not turn blue, and the solution after the reaction is dropped into acidic potassium permanganate solution so that the potassium permanganate solution does not fade; hydrogen and highly toxic gas borane are produced during the reaction, and the solution after the reaction is neither oxidizing nor reducing.

[0029] Comparative Example 3

[0030] Under normal temperature conditions, use an electronic balance to weigh 300g of potassium permanganate wastewater into a beaker, add sulfuric acid to adjust the pH value to 4, add potassium borohydride at a rate of 5g / min, and stir while adding to make the reaction complete (simultaneously use a portable hydrogen detector and a handheld borane gas detector for detection) until the mixed solution has no obvious changes. After the reaction is complete, test the pH value, oxidizability, and reducibility of the mixed solution.

[0031] Test results and phenomena: Portable hydrogen detection test results (range: 0-1000ppm, alarm value set to 50ppm): 65ppm, sound, light and vibration alarm;

[0032] Test results of the handheld borane gas detector (range: 0-100ppm, alarm value set to 10ppm): 0ppm, no alarm;

[0033] The mixed solution is dark brown, pH=7.20, starch potassium iodide test paper turns blue, and the solution after the reaction is dropped into acidic potassium permanganate solution to make the potassium permanganate solution fade; hydrogen is produced during the reaction, and the solution after the reaction still has oxidizing and reducing properties.

[0034] Comparative Example 4

[0035] Under normal temperature conditions, use an electronic balance to weigh 300g of potassium permanganate wastewater into a beaker, add sulfuric acid to adjust the pH value to 2, add potassium borohydride at a rate of 15g / min (detected with a portable hydrogen detector and a handheld borane gas detector at the same time), and stir while adding until the mixed solution is colorless and transparent. After the reaction is completed, test the pH, oxidizing property, and reducing property of the mixed solution.

[0036] Test results and phenomena: Portable hydrogen detection test results (range: 0-1000ppm, alarm value set to 50ppm): 87ppm, sound, light and vibration alarm;

[0037] The test results of the handheld borane gas detector (range: 0-100ppm, alarm value set to 10ppm): 15ppm, sound, light and vibration alarm.

[0038] The mixed solution is colorless and transparent, pH=6.75, starch potassium iodide test paper does not turn blue, and the solution after the reaction is dropped into acidic potassium permanganate solution without causing the potassium permanganate solution to fade; hydrogen and highly toxic gas borane are produced during the reaction, and the solution after the reaction is neither oxidizing nor reducing.

[0039] Implementation Example 1

[0040] Under normal temperature conditions, use an electronic balance to weigh 300g of potassium permanganate wastewater into a beaker, add sulfuric acid to adjust the pH value to 2, add potassium borohydride at a rate of 5g / min (detected with a portable hydrogen detector and a handheld borane gas detector at the same time), and stir while adding until the mixed solution is colorless and transparent. After the reaction is completed, test the pH, oxidizing property, and reducing property of the mixed solution.

[0041] Test results and phenomena: Portable hydrogen detection test results (range: 0-1000ppm, alarm value set to 50ppm): 76ppm, sound, light and vibration alarm;

[0042] The test results of the handheld borane gas detector (range: 0-100ppm, alarm value set to 10ppm): 0ppm, no alarm.

[0043] The mixed solution is colorless and transparent, pH=6.75, starch potassium iodide test paper does not turn blue, and the solution after the reaction does not fade when dropped into acidic potassium permanganate solution; hydrogen is produced during the reaction, and the solution after the reaction is neither oxidizing nor reducing.

[0044] Implementation Example 2

[0045] Under normal temperature conditions, use an electronic balance to weigh 6000g of potassium permanganate wastewater into a plastic basket, add sulfuric acid to adjust the pH value to 2.5, add sodium borohydride at a rate of 8g / min (simultaneously use a portable hydrogen detector and a handheld borane gas detector for detection), and stir while adding until the mixed solution becomes colorless and transparent. After the reaction is completed, test the pH, oxidizing property, and reducing property of the mixed solution.

[0046] Test results and phenomena: Portable hydrogen detection test results (range: 0-1000ppm, alarm value set to 50ppm): 655ppm, sound, light and vibration alarm;

[0047] The test results of the handheld borane gas detector (range: 0-100ppm, alarm value set to 10ppm): 0ppm, no alarm.

[0048] The mixed solution is colorless and transparent, pH=7.03, starch potassium iodide test paper does not turn blue, and the solution after the reaction does not fade when dropped into acidic potassium permanganate solution; hydrogen is produced during the reaction, and the solution after the reaction is neither oxidizing nor reducing.

[0049] Implementation Example 3

[0050] Under normal temperature conditions, use an electronic scale to weigh 600 kg of potassium permanganate wastewater into the reaction tank, add sulfuric acid to adjust the pH value to 3, and add potassium borohydride at a rate of 10 g / min (detected with a portable hydrogen detector and a handheld borane gas detector at the same time) while stirring until the mixed solution becomes colorless and transparent. After the reaction is completed, test the pH, oxidizing property, and reducing property of the mixed solution.

[0051] Test results and phenomena: Portable hydrogen detection test results (range: 0-1000ppm, alarm value set to 50ppm): 1000ppm, sound, light and vibration alarm;

[0052] The test results of the handheld borane gas detector (range: 0-100ppm, alarm value set to 10ppm): 0ppm, no alarm.

[0053] The mixed solution is colorless and transparent, pH=7.15, starch potassium iodide test paper does not turn blue, and the solution after the reaction does not fade when dropped into acidic potassium permanganate solution; hydrogen is produced during the reaction, and the solution after the reaction is neither oxidizing nor reducing.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for treating potassium permanganate wastewater, characterized in that: The following steps are involved: Adding an acid solution to the potassium permanganate wastewater to adjust the pH value to 2-3, and adding a waste reducing agent at a rate of less than 10 g / min until the potassium permanganate wastewater fades to colorless; The waste reducing agent is waste potassium borohydride or sodium borohydride; The acid added to the potassium permanganate wastewater is sulfuric acid, which has a pH <1; The pH value of the potassium permanganate wastewater solution after the reaction is 6-8.

2. A method for disposing of potassium permanganate wastewater as claimed in claim 1, characterized in that: When the potassium permanganate wastewater after treatment is tested with starch potassium iodide test paper, the test paper does not turn blue; when the potassium permanganate wastewater after treatment is tested with acidic potassium permanganate solution, the acidic potassium permanganate solution does not fade.