A solid powder for treating formaldehyde-containing wastewater, a preparation method and application thereof

Abstract

The application provides a solid powder for treating formaldehyde-containing wastewater and a preparation method and application thereof. The method comprises the following steps: mixing hydrometallurgy device waste and water to obtain a mixture; and treating the mixture at high temperature under stirring to obtain a target solid powder; wherein the hydrometallurgy device waste comprises cobalt hydroxide, chromium hydroxide, polyaluminum chloride, polyacrylamide, activated carbon powder, phosphate ester kerosene and calcium hydroxide; the polyacrylamide is decomposed to generate ammonia gas under high-temperature alkaline conditions, which plays a role of hole expansion on the solid powder, and greatly improves the solid surface area of the powder. The solid powder has a good treatment effect on formaldehyde in acrylic acid device wastewater, and fully utilizes the peroxide-containing wastewater as an oxidizing agent to oxidize formaldehyde in the wastewater, so that the purpose of waste treatment by waste is achieved, and the biochemical property of the wastewater is improved.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a solid powder for treating formaldehyde-containing wastewater, its preparation method, and its application. Background Technology

[0002] Formaldehyde has a wide range of uses in chemical enterprises, resulting in numerous sources of formaldehyde wastewater. Chemical companies utilize large quantities of formaldehyde raw materials in the production of resins, plastics, leather, fibers, and preservatives. Some of this formaldehyde becomes waste after production, which, if not properly treated, can become a serious source of pollution. The most harmful component in formaldehyde wastewater is, of course, the large amount of formaldehyde itself. Formaldehyde is extremely harmful to human health and has been identified by the World Health Organization as a carcinogenic and teratogenic toxic substance, seriously threatening the human sense of smell, liver and lung function, and immune tissues; it is an extremely difficult global problem to solve. Besides formaldehyde, formaldehyde wastewater also contains benzene, trioxymethylene, dioxane, and other substances, all of which are more or less polluting or toxic. Low concentrations of formaldehyde wastewater inhibit the growth of microorganisms, causing a considerable impact on the ecological environment. High concentrations of formaldehyde wastewater further damage proteins, causing microbial death and irreversible damage to the ecological environment.

[0003] Currently, commonly used methods for treating formaldehyde wastewater include biological methods and Fenton oxidation.

[0004] Biological treatment of formaldehyde-containing wastewater mostly employs a combination of anaerobic and aerobic biological methods. Anaerobic biological treatment can handle high concentrations of toxic and harmful wastewater, degrading formaldehyde into simple, stable compounds while significantly reducing COD in the wastewater. Aerobic biological treatment metabolizes the small molecules produced during anaerobic biological treatment, ultimately stabilizing them as low-energy inorganic substances. Biological methods offer the advantage of low operating costs; however, due to the high biotoxicity of formaldehyde, biological methods can only treat low-concentration formaldehyde wastewater, and are difficult to treat wastewater with formaldehyde levels exceeding 500 ppm.

[0005] Fenton's reagent method involves using Fe... 2+ When combined with H₂O₂ under acidic conditions, it generates hydroxyl radicals (·OH), exhibiting strong oxidizing properties. These highly reactive hydroxyl radicals react with organic matter, promoting its degradation and mineralization into inorganic substances such as CO₂ and H₂O, rapidly and completely oxidizing and degrading the organic matter within a short time. The Fenton reagent oxidation process is widely used in industrial wastewater treatment due to its advantages of simple operation, readily available reactants, and low investment. The Fenton oxidation method can treat formaldehyde wastewater with high and low concentrations, but the process involves the use of Fe... 2+ As a catalyst, it produces a large amount of iron sludge, which is costly to treat as hazardous waste.

[0006] Since its industrial production in the 1930s, acrylic acid has undergone several technological advancements, including the cyanoethanol method, carbonyl synthesis, ketene method, acrylonitrile hydrolysis, and the two-step oxidation process. Currently, the two-step oxidation process is the primary method for producing acrylic acid. This process requires water to absorb the oxidation products, followed by separation and refining to obtain the final acrylic acid product. Consequently, a large amount of wastewater is generated during the production of acrylic acid and its esters. Wastewater from acrylic acid and ester production is characterized by large volume, high organic content, complex pollutant composition, and significant water quality fluctuations. The wastewater from acrylic acid and ester plants is a high-concentration organic industrial wastewater, with a chemical oxygen demand (CODcr) typically between 30,000 and 50,000 mg / L. It is strongly acidic and primarily contains acetic acid (3.0-6.0%), acrylic acid and its esters (0.02-3.0%), formaldehyde (0.04-4%), toluene, and other organic compounds (0-2%). It contains numerous recalcitrant and toxic pollutants, making treatment extremely difficult.

[0007] During the production process of the PO / SM unit, air is used to oxidize ethylbenzene to EBHP. This process generates a large amount of wastewater containing peroxides, which has strong oxidizing and biological toxicity and is difficult to treat.

[0008] In summary, there is a need to develop a universal treatment process that can handle both high and low concentrations of formaldehyde without generating solid waste or secondary pollution, and that can utilize the strong oxidizing properties of peroxides to treat formaldehyde wastewater, thereby achieving the goal of treating waste with waste. Summary of the Invention

[0009] One of the objectives of this invention is to provide a method for preparing a solid powder for treating formaldehyde-containing wastewater. This solid powder treats formaldehyde, promotes its oxidation to formic acid, reduces its biotoxicity, and provides stable treatment results.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] A method for preparing a solid powder for treating formaldehyde-containing wastewater, the method comprising the following steps:

[0012] S1: Waste from hydrometallurgical equipment is mixed with water to obtain a mixture;

[0013] S2: The mixture is subjected to high temperature treatment under stirring to obtain the target solid powder;

[0014] Among them, the waste from the hydrometallurgical equipment mentioned in S1 includes cobalt hydroxide, chromium hydroxide, polyaluminum chloride, polyacrylamide, activated carbon powder, phosphate ester kerosene, and calcium hydroxide.

[0015] The powdered reagent in this invention is made from waste from hydrometallurgical equipment. Its main components contain a certain amount of alkaline substances. Under high-temperature conditions, these alkaline substances promote the decomposition of the C-NH2 carbon-nitrogen bonds in polyacrylamide, generating ammonia gas. With stirring, the ammonia gas is evenly distributed in the solid-liquid slurry. As the mixture is dried at high temperature, a large number of porous structures are formed, greatly increasing the solid surface area of ​​the powder. As an additional effect, the organic peroxides contained in the powder are decomposed into highly oxidizing hydroxyl radicals, breaking down large molecules in the wastewater into smaller acid molecules. Some of these smaller carboxylic acids are further oxidized to CO2 and H2O.

[0016] In one embodiment of the present invention, the composition of the waste from the hydrometallurgical plant in S1 is as follows, based on the total mass of the waste after the water has been evaporated:

[0017] Cobalt hydroxide 5-25 wt%, preferably 15-22 wt%.

[0018] Chromium hydroxide 10-20 wt%, preferably 12-15 wt%.

[0019] Polyaluminum chloride 11-25 wt%,

[0020] Polyacrylamide 3-12 wt%, preferably 4-8 wt%.

[0021] Activated carbon powder 5-25 wt%,

[0022] Phosphate ester kerosene 3-10 wt%, preferably 4-6 wt%.

[0023] Calcium hydroxide 2-10 wt%, preferably 3-5 wt%.

[0024] In one embodiment of the present invention, the ratio of waste to water in the S1 hydrometallurgical device is 1:(3-8), preferably 1:(4-6).

[0025] In one embodiment of the present invention, the temperature of the high-temperature treatment in S2 is 100-130°C.

[0026] In one embodiment of the present invention, S2 is based on the weight of the solid powder, and the solid powder comprises the following components:

[0027] Cobalt hydroxide 5.5–25.5 wt%, preferably 15–22 wt%.

[0028] Chromium hydroxide 11-21 wt%, preferably 13-16 wt%.

[0029] Polyaluminum chloride 12-27 wt%,

[0030] Polyacrylamide 1-4 wt%, preferably 1.2-2.5 wt%.

[0031] Activated carbon powder 6-28 wt%,

[0032] Phosphate ester kerosene 3-12 wt%, preferably 5-7 wt%.

[0033] Calcium hydroxide 3–12 wt%, preferably 4–7 wt%.

[0034] Another object of the present invention is to provide a solid powder for treating formaldehyde-containing wastewater.

[0035] A solid powder for treating formaldehyde-containing wastewater, the solid powder being prepared using the above-described preparation method, and comprising the following components based on the weight of the solid powder:

[0036] Cobalt hydroxide 5.5–25.5 wt%, preferably 15–22 wt%.

[0037] Chromium hydroxide 11-21 wt%, preferably 13-16 wt%.

[0038] Polyaluminum chloride 12-27 wt%,

[0039] Polyacrylamide 1-4 wt%, preferably 1.2-2.5 wt%.

[0040] Activated carbon powder 6-28 wt%,

[0041] Phosphate ester kerosene 3-12 wt%, preferably 5-7 wt%.

[0042] Calcium hydroxide 3–12 wt%, preferably 4–7 wt%.

[0043] Another object of the present invention is to provide a use of a solid powder for treating formaldehyde-containing wastewater.

[0044] The use of a solid powder for treating formaldehyde-containing wastewater, wherein the solid powder is a solid powder prepared by the above-described preparation method, or is the solid powder described above, and the solid powder is used to treat formaldehyde-containing wastewater, preferably for the combined treatment of peroxide-containing wastewater and formaldehyde-containing wastewater, more preferably for the combined treatment of PO / SM peroxide-containing wastewater and formaldehyde-containing wastewater from an acrylic acid plant.

[0045] Another object of the present invention is to provide a method for the combined treatment of wastewater containing peroxide and wastewater containing formaldehyde.

[0046] A method for jointly treating wastewater containing peroxide and wastewater containing formaldehyde, wherein the method uses a solid powder prepared by the above-described preparation method, or is a solid powder prepared as described above, and the method includes the following steps:

[0047] SS1: Wastewater containing peroxides and wastewater containing formaldehyde are mixed to obtain mixed wastewater;

[0048] SS2: Adjusts the pH value of the mixed wastewater;

[0049] SS3: Mixed wastewater enters the reactor, and solid powder for treating formaldehyde-containing wastewater is added to the reactor for reaction;

[0050] SS4: After the reaction is completed, solid and liquid are separated. The solid is treated as hazardous waste, and the liquid meets the biochemical indicators and is discharged.

[0051] In one embodiment of the present invention, the total amount of peroxide in SS1, measured as hydrogen peroxide, is higher than the formaldehyde content. This can be adjusted by those skilled in the art based on the actual treatment process requirements, measured by mass per unit time. Preferably, the peroxide-containing wastewater in SS1 comes from a PO / SM unit. Preferably, the organic peroxide content in the peroxide-containing wastewater in SS1 is ≤30000 mg / L, and the COD is ≤80000 mg / L. More preferably, the methyl hydrogen peroxide content in the peroxide-containing wastewater is ≤25000 mg / L. Preferably, the formaldehyde-containing wastewater in SS1 comes from an acrylic acid unit. Preferably, the formaldehyde content in the formaldehyde-containing wastewater in SS1 is ≤40000 mg / L, and the COD is ≤50000 mg / L.

[0052] In one embodiment of the present invention, the pH value of SS2 is adjusted with alkali or acid.

[0053] In one embodiment of the present invention, the pH value in SS2 is adjusted to 9-11.

[0054] In one embodiment of the present invention, a stirred tank reactor is used in SS3.

[0055] In one embodiment of the present invention, the amount of solid powder added to SS3 is 5-10 g / L.

[0056] In one embodiment of the present invention, the SS3 reaction temperature is 40-60°C, the wastewater is mixed, and the reaction time is 2-5 hours.

[0057] In one embodiment of the present invention, the formaldehyde content in the liquid after SS4 separation is ≤700mg / L and the COD is ≤38000mg / L.

[0058] In one application of this invention, wastewater enters a batch stirred tank reactor, and powdered reagents are added to the reactor. An adsorption-extraction-catalytic oxidation synergistic reaction occurs on the surface of the powdered reagents. The powdered reagents have a porous structure, and under the impetus of stirring, they rapidly contact peroxides. The turbulent stirring, extraction of phosphate esters, and the porous surface structure collectively improve the diffusion mass transfer rate. The contacting peroxides decompose into [OH] and [O], which have high oxidizing properties. During contact with formaldehyde, they oxidize it to formic acid, further enhancing its biochemical properties. Furthermore, increasing the formaldehyde oxidation reaction temperature and reaction time is beneficial for increasing the decomposition efficiency of peroxides and formaldehyde, but the corresponding operating and investment costs will increase. In addition, with increasing time and temperature, a large amount of organic matter is converted into carbon dioxide or small molecule organic matter. Small molecule substances have high biochemical properties and are difficult to continue reacting; therefore, the reaction temperature and time need to be optimized. Unlike hydrogen peroxide-like peroxides, organic peroxides, especially methyl hydrogen peroxide in POSM wastewater, have low decomposition efficiency at room temperature and pressure without a catalyst, and cannot be fully decomposed into hydroxyl radicals. However, in the presence of solid powder, the active sites greatly reduce the activation energy of the reaction, which will rapidly decompose the organic peroxides into [OH], thereby decomposing and removing the organic matter.

[0059] In one application of the present invention, unlike hydrogen peroxide-type peroxides, organic peroxides, especially methyl hydrogen peroxide in POSM wastewater, have low decomposition efficiency at room temperature and pressure without a catalyst, and cannot be fully decomposed into hydroxyl radicals. However, in the presence of solid powder, the active sites greatly reduce the activation energy of the reaction, which will rapidly decompose the organic peroxides into [OH], thereby decomposing and removing the organic matter.

[0060] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0061] (1) The raw materials used in this invention are solid waste from the equipment, which are simple and readily available.

[0062] (2) After simple and effective treatment, solid waste can be transformed into a porous additive with excellent effect, and the treatment process is simple.

[0063] (3) This scheme proposes a method for the combined treatment of wastewater containing peroxide and formaldehyde, which makes full use of the oxidizing properties of peroxide to remove formaldehyde and other organic compounds, thereby achieving the purpose of treating waste with waste. Detailed Implementation

[0064] The following specific embodiments further illustrate the technical solution and effects of the present invention. These embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Simple modifications made to the present invention based on the concept of the present invention are all within the scope of protection claimed by the present invention.

[0065] The batch reactor was purchased from Anhui Wufu Fluid Equipment Co., Ltd.

[0066] Powder raw materials, wastewater treatment workshop of hydrometallurgical unit of Wanhua Chemical Co., Ltd.

[0067] PO / SM wastewater containing organic peroxides, Wanhua Chemical Co., Ltd.;

[0068] Formaldehyde-containing wastewater from an acrylic acid plant, Wanhua Chemical Co., Ltd.

[0069] GC analysis conditions: An Agilent HP-5 gas chromatographic column with dimensions of 30m*530μm*1.5μm was used. The column temperature was set to 70℃ and held for 5 min, then increased to 300℃ at a rate of 5℃ / min and held for 10 min for water quality principal component analysis.

[0070] COD analysis: The national standard potassium dichromate oxidation analysis method was used.

[0071] In the following examples, the sampling and analysis results of wastewater containing organic peroxides are shown in Table 1.

[0072] Table 1 Composition of Wastewater #1

[0073]

[0074]

[0075] Table 2 Composition of Wastewater #2

[0076]

[0077]

[0078] Table 3 Composition of Wastewater #3

[0079]

[0080]

[0081]

[0082] Example 1

[0083] Preparation of formaldehyde removal powder #0 and its effect on the combined treatment of POSM wastewater and formaldehyde wastewater.

[0084] A 100g wet sample from the hydrometallurgical unit was placed in an evaporating dish. The sample consisted of the following components: cobalt hydroxide 22wt%, chromium hydroxide 15wt%, polyaluminum chloride 23wt%, polyacrylamide 3wt%, activated carbon powder 17wt%, phosphate ester kerosene 10wt%, and calcium hydroxide 10wt%. The sample was placed in an oven at 90℃ for 5 hours. 20g of the dried sample was then ground using a small ball mill to a particle size (D50) of 5 micrometers.

[0085] The above 20g sample was uniformly mixed with 100g of pure water, and stirred magnetically at 400rpm for 100min. Heating was then applied at 120℃ for 5h to obtain the expanded-pore formaldehyde removal powder reagent. The total mass of the powder was: cobalt hydroxide 22.4wt%, chromium hydroxide 15.3wt%, polyaluminum chloride 23.5wt%, polyacrylamide 1wt%, activated carbon powder 17.7wt%, phosphate ester kerosene 10.2wt%, and calcium hydroxide 10.2wt%. Its bulk density was 1.23g / cm³. 3 Specific surface area is 110m² 2 / g.

[0086] Take the POSM wastewater and formaldehyde wastewater shown in Table 1 and place them in a beaker. Add 4.5g of 32wt% sodium hydroxide, adjust the pH to 10, and add it to a batch reactor. Adjust the reaction temperature to 50℃ and the reaction time to 3h. Add 2.8g of 0# powder. The formaldehyde content is reduced to 65mg / L and the biochemical B / C ratio is increased to 0.5.

[0087] Example 2

[0088] Preparation of Formaldehyde Removal Powder No. 1 and Evaluation of its Combined Treatment Effect on POSM Wastewater and Formaldehyde Wastewater.

[0089] A 100g wet sample from the hydrometallurgical unit was placed in an evaporating dish. The sample consisted of the following components: cobalt hydroxide 20wt%, chromium hydroxide 14wt%, polyaluminum chloride 17wt%, polyacrylamide 12wt%, activated carbon powder 17wt%, phosphate ester kerosene 10wt%, and calcium hydroxide 10wt%. The sample was placed in an oven at 90℃ for 5 hours. 20g of the dried sample was then ground using a small ball mill to a particle size (D50) of 5 micrometers.

[0090] The above 20g sample was uniformly mixed with 100g of pure water, and stirred magnetically at 400rpm for 100min. Heating was then applied at 120℃ for 5h to obtain the expanded-pore formaldehyde removal powder reagent. The total mass of the powder was: cobalt hydroxide 21.7wt%, chromium hydroxide 15.2wt%, polyaluminum chloride 18.5wt%, polyacrylamide 4.3wt%, activated carbon powder 18.5wt%, phosphate ester kerosene 10.9wt%, and calcium hydroxide 10.9wt%. Its bulk density was 1.25g / cm³. 3 Specific surface area is 120m² 2 / g.

[0091] Take the POSM wastewater and formaldehyde wastewater shown in Table 2 and put them into a beaker. Add 4g of 32wt% sodium hydroxide, adjust the pH to 10.5, add it to the batch reactor, adjust the reaction temperature to 40℃, and the reaction time to 2h. Add 5g of No. 1 powder. The formaldehyde content is reduced to 37mg / L and the biochemical B / C ratio is increased to 0.55.

[0092] Example 3

[0093] Preparation of Formaldehyde Removal Powder No. 2 and Evaluation of its Combined Treatment Effect on POSM Wastewater and Formaldehyde Wastewater.

[0094] A 100g wet sample from the hydrometallurgical unit was placed in an evaporating dish. The sample consisted of the following components: cobalt hydroxide 8wt%, chromium hydroxide 20wt%, polyaluminum chloride 21wt%, polyacrylamide 6wt%, activated carbon powder 25wt%, phosphate ester kerosene 10wt%, and calcium hydroxide 10wt%. The sample was placed in an oven at 90℃ for 5 hours. 20g of the dried sample was then ground using a small ball mill to a particle size (D50) of 5 micrometers.

[0095] The above 20g sample was uniformly mixed with 100g of pure water, and stirred magnetically at 400rpm for 100min. Heating was then applied at 120℃ for 5h to obtain the expanded-pore formaldehyde removal powder reagent. The total mass of the powder was: cobalt hydroxide 8.3wt%, chromium hydroxide 20.8wt%, polyaluminum chloride 21.9wt%, polyacrylamide 2.1wt%, activated carbon powder 26.0wt%, phosphate ester kerosene 10.4wt%, and calcium hydroxide 10.4wt%. Its bulk density was 1.25g / cm³. 3 Specific surface area is 115m² 2 / g.

[0096] Take the POSM wastewater and formaldehyde wastewater shown in Table 1 and place them in a beaker. Add 4.5g of 32wt% sodium hydroxide, adjust the pH to 10, and add it to a batch reactor. Adjust the reaction temperature to 50℃ and the reaction time to 3h. Add 2.8g of No. 2 powder. The formaldehyde content is reduced to 28.9mg / L and the biochemical B / C ratio is increased to 0.6.

[0097] Example 4

[0098] Preparation of Formaldehyde Removal Powder No. 3 and Evaluation of its Combined Treatment Effect on POSM Wastewater and Formaldehyde Wastewater.

[0099] A 100g wet sample from the hydrometallurgical unit was placed in an evaporating dish. The sample consisted of the following components: cobalt hydroxide 22wt%, chromium hydroxide 10wt%, polyaluminum chloride 21wt%, polyacrylamide 6wt%, activated carbon powder 21wt%, phosphate ester kerosene 10wt%, and calcium hydroxide 10wt%. The sample was placed in an oven at 90℃ for 5 hours. 20g of the dried sample was then ground using a small ball mill to a particle size (D50) of 5 micrometers.

[0100] The above 20g sample was uniformly mixed with 100g of pure water, and stirred magnetically at 400rpm for 100min. Heating was then initiated at 120℃, and the mixture was dried for 5h to obtain the expanded-pore formaldehyde removal powder reagent. The total mass of the powder was: cobalt hydroxide 22.9wt%, chromium hydroxide 10.4wt%, polyaluminum chloride 21.9wt%, polyacrylamide 2.1wt%, activated carbon powder 21.9wt%, phosphate ester kerosene 10.4wt%, and calcium hydroxide 10.4wt%. Its bulk density was 1.26g / cm³. 3 Specific surface area is 120m² 2 / g.

[0101] Take the POSM wastewater and formaldehyde wastewater shown in Table 3 and put them into a beaker. Add 3g of 32wt% sodium hydroxide, adjust the pH to 9, add it to the batch reactor, adjust the reaction temperature to 55℃, and the reaction time to 4.5h. Add 9g of No. 3 powder. The formaldehyde content is reduced to 30.5mg / L and the biochemical B / C ratio is increased to 0.57.

[0102] Example 5

[0103] Preparation of Formaldehyde Removal Powder No. 4 and Evaluation of its Combined Treatment Effect on POSM Wastewater and Formaldehyde Wastewater.

[0104] A 100g wet sample from the hydrometallurgical unit was placed in an evaporating dish. The sample consisted of the following components: cobalt hydroxide 20wt%, chromium hydroxide 13wt%, polyaluminum chloride 21wt%, polyacrylamide 6wt%, activated carbon powder 25wt%, phosphate ester kerosene 5wt%, and calcium hydroxide 10wt%. The sample was placed in an oven at 90℃ for 5 hours. 20g of the dried sample was then ground using a small ball mill to a particle size (D50) of 5 micrometers.

[0105] The above 20g sample was uniformly mixed with 100g of pure water, and stirred magnetically at 400rpm for 100min. Heating was then applied at 120℃ for 5h to obtain the expanded-pore formaldehyde removal powder reagent. The total mass of the powder was: cobalt hydroxide 20.8wt%, chromium hydroxide 13.5wt%, polyaluminum chloride 21.9wt%, polyacrylamide 2.1wt%, activated carbon powder 26wt%, phosphate ester kerosene 5.2wt%, and calcium hydroxide 10.4wt%. Its bulk density was 1.21g / cm³. 3 Specific surface area is 120m² 2 / g.

[0106] Take the POSM wastewater and formaldehyde wastewater shown in Table 1 and place them in a beaker. Add 4.5g of 32wt% sodium hydroxide, adjust the pH to 10, and add it to a batch reactor. Adjust the reaction temperature to 50℃ and the reaction time to 3h. Add 2.8g of No. 4 powder. The formaldehyde content is reduced to 34.5mg / L and the biochemical B / C ratio is increased to 0.6.

[0107] Example 6

[0108] Preparation of Formaldehyde Removal Powder No. 5 and Evaluation of its Combined Treatment Effect on POSM Wastewater and Formaldehyde Wastewater.

[0109] A 100g wet sample from the hydrometallurgical unit was placed in an evaporating dish. The sample consisted of the following components: cobalt hydroxide 25wt%, chromium hydroxide 15wt%, polyaluminum chloride 21wt%, polyacrylamide 6wt%, activated carbon powder 25wt%, phosphate ester kerosene 3wt%, and calcium hydroxide 5wt%. The sample was placed in an oven at 90℃ for 5 hours. 20g of the dried sample was then ground using a small ball mill to a particle size (D50) of 5 micrometers.

[0110] The above 20g sample was uniformly mixed with 100g of pure water, and stirred magnetically at 400rpm for 100min. Heating was then applied at 120℃ for 5h to obtain the expanded-pore formaldehyde removal powder reagent. The total mass of the powder was: cobalt hydroxide 26wt%, chromium hydroxide 15.6wt%, polyaluminum chloride 21.9wt%, polyacrylamide 2.1wt%, activated carbon powder 26wt%, phosphate ester kerosene 3.1wt%, and calcium hydroxide 5.2wt%. Its bulk density was 1.24g / cm³. 3 Specific surface area is 120m² 2 / g.

[0111] Take the POSM wastewater and formaldehyde wastewater shown in Table 1 and put them into a beaker. Add 4.5g of 32wt% sodium hydroxide, adjust the pH to 10, add it to the batch reactor, adjust the reaction temperature to 50℃, and the reaction time to 3h. Add 2.8g of No. 5 powder, and the formaldehyde content will be reduced to 40.5mg / L and the biochemical B / C ratio will be increased to 0.55.

[0112] Comparative Example 1

[0113] Compared with Example 1, the difference is the removal of polyacrylamide.

[0114] Preparation of Formaldehyde Removal Powder No. 6 and Evaluation of its Combined Treatment Effect on POSM Wastewater and Formaldehyde Wastewater.

[0115] 100g of wet sample from a hydrometallurgical unit was placed in an evaporating dish. The total mass of the waste from the hydrometallurgical unit after evaporation at 85℃ was: cobalt hydroxide 22wt%, chromium hydroxide 15wt%, polyaluminum chloride 23wt%, polyacrylamide 3wt%, activated carbon powder 17wt%, phosphate ester kerosene 10wt%, and calcium hydroxide 10wt%. The above raw materials were mixed with dichloromethane at a mass ratio of 1:1 in a glass beaker and stirred thoroughly with a glass rod for 10 minutes. After stirring, the material was vacuum filtered through 5μm filter paper to remove the extractant. The filtered material was then mixed with pure water at a mass ratio of 1:1, and the extraction and filtration process was repeated twice to obtain filter material extracted with dichloromethane and rinsed with pure water. This material was placed in an oven at 90℃ and dried for 5 hours. 20g of the dried sample was then ground using a small ball mill to a particle size D50 of 5 micrometers.

[0116] The above 20g sample was uniformly mixed with 100g of pure water, and stirred magnetically at 400rpm for 100min. Heating was then applied at 120℃ for 5h to obtain the expanded-pore formaldehyde removal powder reagent. The total mass of the powder was: cobalt hydroxide 25.8wt%, chromium hydroxide 17.6wt%, polyaluminum chloride 27wt%, polyacrylamide 0wt%, activated carbon powder 19.9wt%, phosphate ester kerosene 0wt%, and calcium hydroxide 11.7wt%. Its bulk density was 2.1g / cm³. 3 Specific surface area is 10m² 2 / g.

[0117] Take the POSM wastewater and formaldehyde wastewater shown in Table 1 and put them into a beaker. Add 4.5g of 32wt% sodium hydroxide, adjust the pH to 10, add it to the batch reactor, adjust the reaction temperature to 50℃, and the reaction time to 3h. Add 2.8g of No. 6 powder. The formaldehyde content is reduced to 7890mg / L and the biochemical B / C ratio is increased to 0.

Claims

1. A method for preparing a solid powder for treating formaldehyde-containing wastewater, characterized by, The method comprises the following steps: S1: mixing the hydrometallurgy device waste with water to obtain a mixture; S2: high-temperature treatment of the mixture in a stirring state to obtain a target solid powder; The hydrometallurgy device waste in S1 comprises cobalt hydroxide, chromium hydroxide, polyaluminum chloride, polyacrylamide, activated carbon powder, phosphate ester kerosene, and calcium hydroxide. The composition of the hydrometallurgy device waste in S1 is as follows, based on the total mass of the waste after the water is evaporated: 5-25wt% of cobalt hydroxide, 10-20wt% of chromium hydroxide, 11-25wt% of polyaluminum chloride, 3-12wt% of polyacrylamide, 5-25wt% of activated carbon powder, 3-10wt% of phosphate ester kerosene, 2-10wt% of calcium hydroxide. The temperature of the high-temperature treatment in S2 is 100-130℃.

2. The production method according to claim 1, characterized by, The composition of the hydrometallurgy device waste in S1 is as follows, based on the total mass of the waste after the water is evaporated: 15-22wt% of cobalt hydroxide, 12-15wt% of chromium hydroxide, 4-8wt% of polyacrylamide, 4-6wt% of phosphate ester kerosene, 3-5wt% of calcium hydroxide. And / or, the ratio of the hydrometallurgy device waste in S1 to water is 1:(3-8).

3. The production method according to claim 1 or 2, characterized by, The ratio of the hydrometallurgy device waste in S1 to water is 1:(4-6).

4. The production method according to claim 1 or 2, characterized by, The solid powder in S2 comprises the following components, based on the weight of the solid powder: 5.5-25.5wt% of cobalt hydroxide, 11-21wt% of chromium hydroxide, 12-27wt% of polyaluminum chloride, 1-4wt% of polyacrylamide, 6-28wt% of activated carbon powder, 3-12wt% of phosphate ester kerosene, 3-12wt% of calcium hydroxide.

5. The preparation method according to claim 4, characterized in that, The solid powder in S2 comprises the following components, based on the weight of the solid powder: 15-22wt% of cobalt hydroxide, 13-16wt% of chromium hydroxide, 1.2-2.5wt% of polyacrylamide, 5-7wt% of phosphate ester kerosene, 4-7wt% of calcium hydroxide.

6. A solid powder for treating formaldehyde-containing wastewater, which is prepared by the method according to any one of claims 1 to 5, characterized in that, The solid powder comprises the following components, based on the weight of the solid powder: 5.5-25.5wt% of cobalt hydroxide, 11-21wt% of chromium hydroxide, 12-27wt% of polyaluminum chloride, 1-4wt% of polyacrylamide, 6-28wt% of activated carbon powder, 3-12wt% of phosphate ester kerosene, 3-12wt% of calcium hydroxide.

7. The solid powder according to claim 6, characterized in that, The solid powder comprises the following components, based on the weight of the solid powder: 15-22wt% of cobalt hydroxide, 13-16wt% of chromium hydroxide, 1.2-2.5wt% of polyacrylamide, 5-7wt% of phosphate ester kerosene, 4-7wt% of calcium hydroxide.

8. Use of a solid powder for treating formaldehyde-containing wastewater, wherein the solid powder is prepared by the method of any one of claims 1-5, or is the solid powder of claim 6 or 7, and the solid powder is used for treating formaldehyde-containing wastewater.

9. The use of claim 8, wherein the solid powder is used for jointly treating peroxide-containing wastewater and formaldehyde-containing wastewater.

10. The use of claim 9, wherein the solid powder is used for jointly treating PO / SM peroxide-containing wastewater and acrylic device formaldehyde-containing wastewater.

11. A method for treating peroxide-containing wastewater and formaldehyde-containing wastewater in combination, the method using the solid powder prepared by the preparation method of any one of claims 1-5, or the solid powder of claim 6 or 7, the method comprising the following steps: SS1: mixing the peroxide-containing wastewater and the formaldehyde-containing wastewater to obtain mixed wastewater; SS2: adjusting the pH value of the mixed wastewater; SS3: feeding the mixed wastewater into a reaction kettle, and adding the solid powder for treating formaldehyde-containing wastewater in the kettle for reaction; SS4: after the reaction is completed, separating the solid and the liquid, treating the solid as hazardous waste, and discharging the liquid to meet the biochemical indicators.

12. The method of claim 11, wherein, In SS1, the total amount of peroxide calculated based on hydrogen peroxide is higher than the formaldehyde content, in terms of mass per unit time; And / or, in SS2, the pH value is adjusted by using alkali or acid; And / or, in SS2, the pH value is adjusted to 9-11; And / or, in SS3, a stirred tank reactor is used; And / or, in SS3, the amount of the solid powder added is 5-10 g / L; And / or, in SS3, the reaction temperature is 40-60℃, the mixed wastewater, and the reaction time is 2-5 h; And / or, in SS4, the formaldehyde content in the separated liquid is ≤700 mg / L, and the COD is ≤38000 mg / L.

13. The method of claim 12, wherein, The peroxide-containing wastewater in SS1 is from a PO / SM device; The organic peroxide content in the peroxide-containing wastewater in SS1 is ≤30000 mg / L, and the COD is ≤80000 mg / L; The formaldehyde-containing wastewater in SS1 is from an acrylic acid device; The formaldehyde content in the formaldehyde-containing wastewater in SS1 is ≤40000 mg / L, and the COD is ≤50000 mg / L.

14. The method of claim 13, wherein, The methyl hydroperoxide content in the peroxide-containing wastewater in SS1 is ≤25000 mg / L.

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