A method for treating chemical wastewater

Abstract

The application relates to the technical field of wastewater treatment, and specifically discloses a chemical wastewater treatment method, which comprises the following steps: S1, introducing the chemical wastewater into a regulating tank, adjusting the pH value of the chemical wastewater, controlling the temperature of the chemical wastewater, filtering, standing, and obtaining pretreated wastewater; S2, adding a modified industrial treatment agent into the pretreated wastewater, stirring and reacting, then adding a coagulant aid, continuously stirring and uniformly distributing, standing and precipitating, carrying out solid-liquid separation, obtaining supernatant and precipitated sludge, and carrying out harmless treatment on the precipitated sludge after dewatering treatment; and S3, carrying out sand filtration treatment on the supernatant, then carrying out ultraviolet disinfection treatment, and obtaining chemical wastewater which can be directly discharged or recycled. The chemical wastewater treatment method has significant treatment advantages and practical value, the removal rates of the chemical oxygen demand, ammonia nitrogen and total phosphorus of the treated chemical wastewater are high, the content of suspended matter in the treated chemical wastewater is low, and the treated chemical wastewater meets the discharge standard.

Description

Technical Field

[0001] This application relates to the field of wastewater treatment technology, and more specifically, to a method for treating chemical wastewater. Background Technology

[0002] Chemical wastewater is characterized by its complex composition, high concentration of pollutants, and difficulty in degradation. It contains large amounts of heavy metal ions, persistent organic matter, and nutrients such as nitrogen and phosphorus. Direct discharge without effective treatment will severely pollute water and soil environments, exacerbate eutrophication, and threaten ecosystem balance and human health. As environmental standards become increasingly stringent, higher demands are placed on the treatment efficiency and pollutant removal precision of chemical wastewater, rendering existing wastewater treatment technologies inadequate for meeting practical needs.

[0003] Currently, the main methods for treating chemical wastewater include physical, chemical, and biological methods. Among them, chemical methods such as chemical flocculation and oxidation-reduction have become the mainstream industrial treatment processes due to their simplicity and speed. However, existing chemical treatment technologies have significant drawbacks: traditional flocculants can only remove suspended impurities and some COD from wastewater, and their removal effect on low-concentration heavy metals and recalcitrant organic matter is limited, making it difficult to meet stringent discharge standards; some advanced wastewater treatment processes require the use of multiple reagents, which not only complicates the process and increases operating costs but also easily generates secondary pollution.

[0004] While existing technologies have attempted to improve wastewater treatment efficiency through composite agents, most suffer from poor agent compatibility and limited effectiveness, failing to achieve simultaneous and deep removal of multiple pollutants. Furthermore, they require large agent dosages and demanding reaction conditions, hindering industrial-scale application. To address these technological bottlenecks, there is an urgent need to develop a highly efficient, environmentally friendly, and low-cost method for treating chemical wastewater. In particular, there is a need to develop a dedicated industrial treatment agent to achieve simultaneous and efficient removal of multiple pollutants from chemical wastewater, simplify the treatment process, reduce operating costs, and overcome the shortcomings of existing technologies. Summary of the Invention

[0005] To address the technical problems mentioned in the background section, this application provides a method for treating chemical wastewater.

[0006] This application provides a method for treating chemical wastewater, employing the following technical solution: A method for treating chemical wastewater includes the following steps: S1. Introduce the chemical wastewater into the equalization tank, adjust the pH value of the chemical wastewater to 6.5-7.5, control the temperature of the chemical wastewater to 25-35℃, filter, and let it stand for 30-40 minutes to obtain the pretreated wastewater. S2. Add modified industrial treatment agent to the pretreated wastewater, stir and react for 40-60 minutes, then add coagulant aid, continue stirring for 20-30 minutes, let it stand to settle, and perform solid-liquid separation to obtain supernatant and precipitated sludge. The precipitated sludge is then dewatered and disposed of in a harmless manner. S3. After sand filtration, the supernatant is then disinfected with ultraviolet light for 15-20 minutes to obtain chemical wastewater that can be directly discharged or recycled.

[0007] Preferably, the preparation method of the modified industrial treatment agent in step S2 is as follows: Modified water treatment adsorbent, polyaluminum chloride, activated carbon, and hydroxylated starch are added to a mixer in sequence and stirred evenly. Then, a composite corrosion inhibitor is added and stirring is continued for 30-40 minutes. After drying and pulverizing to a particle size of 80-100 mesh, the modified industrial treatment agent is obtained.

[0008] Preferably, the mass ratio of the modified water treatment adsorbent, polyaluminum chloride, activated carbon, hydroxylated starch and composite corrosion inhibitor is 20-30:25-35:15-20:10-15:3-6.

[0009] Preferably, the preparation method of the modified water treatment adsorbent includes the following preparation steps: Attapulgite and diatomaceous earth are mixed evenly, calcined and activated, naturally cooled to room temperature, pulverized and sieved to obtain a composite mineral carrier. Deionized water is added to the composite mineral carrier and stirred to disperse evenly. Then, hydroxyethylidene diphosphonic acid, polyepoxysuccinic acid and polyquaternium-7 are added. The mixture is stirred and reacted at 30-45℃ for 2-3 hours. After filtration, washing, drying, pulverizing and sieving, a modified water treatment adsorbent is obtained.

[0010] Preferably, the calcination activation treatment specifically involves: first heating to 300-350℃ at a heating rate of 8-10℃ / min, holding at that temperature for 2-3 hours, and then heating to 420-450℃ at a heating rate of 2-5℃ / min, and calcining for 3-5 hours.

[0011] Preferably, the mass ratio of attapulgite, diatomaceous earth, hydroxyethylidene diphosphonic acid, polyepoxysuccinic acid, and polyquaternium-7 is 30-40:20-30:5-8:3-5:2-4.

[0012] Preferably, the composite corrosion inhibitor is composed of benzotriazole and aminotrimethylenephosphonic acid in a mass ratio of 1:1.2-1.8.

[0013] Preferably, in step S2, the mass ratio of pretreated wastewater, modified industrial treatment agent, and coagulant is 1000:3-8:1-2.

[0014] Preferably, the coagulant is one or more of anionic polyacrylamide, activated silica, and sodium alginate.

[0015] Preferably, the sand filtration process uses a double-layer filter media of quartz sand and anthracite, wherein the mass ratio of quartz sand to anthracite is 1:0.4-0.6, and the filtration rate is 6-10 m / h; the ultraviolet disinfection process has an ultraviolet light intensity of 40-60 μW / cm². 2 The ultraviolet wavelength is 254nm.

[0016] In summary, this application has the following beneficial effects: This application involves gradient calcination activation of attapulgite and diatomaceous earth, followed by modification with a compound of hydroxyethylidene diphosphonic acid, polyepoxysuccinic acid, and polyquaternium-7. This modification results in a porous water treatment adsorbent with a significantly increased number of surface active sites, greatly enhancing its adsorption performance. The calcination activation treatment effectively removes impurities from the mineral carrier, expands its specific surface area, and the synergistic effect of the three modifiers enhances the adsorption capacity of the modified water treatment adsorbent for heavy metal ions and organic pollutants in wastewater, while also improving its dispersibility and stability. This avoids the problem of decreased adsorption efficiency caused by adsorbent agglomeration. Compared to adsorbents modified with a single component or without calcination activation treatment, the modified water treatment adsorbent exhibits a significantly increased adsorption capacity, enabling rapid and efficient removal of pollutants from wastewater.

[0017] This application utilizes a composite corrosion inhibitor formed by combining benzotriazole and aminotrimethylenephosphonic acid, resulting in a significant synergistic corrosion inhibition effect. Benzotriazole forms a dense complex protective film on the equipment surface, preventing corrosive media from contacting the surface, while aminotrimethylenephosphonic acid chelates metal ions in wastewater, reducing corrosion reactions. When combined in a specific ratio, the two components complement each other, significantly improving corrosion inhibition efficiency, further reducing equipment corrosion rates, and extending the service life of the treatment equipment. This approach avoids the problems of large dosages and unstable inhibition effects associated with single corrosion inhibitors, while also reducing reagent consumption. Detailed Implementation

[0018] The present application will be further described in detail below with reference to the embodiments.

[0019] The anionic polyacrylamide used in the embodiments and comparative examples of this application was purchased from Gongyi Sifeng Water Purification Materials Co., Ltd.; benzotriazole was purchased from Jinan Mingjiang Chemical Co., Ltd.; aminotrimethylene phosphonic acid was purchased from Jiangsu Runfeng Synthetic Technology Co., Ltd.; attapulgite (item number: 4-58) was purchased from Lingshou Ruikai Mineral Products Co., Ltd.; diatomaceous earth was purchased from Lingshou Ruikai Mineral Products Co., Ltd.; hydroxyethylidene diphosphonic acid was purchased from Hubei Xingyan New Materials Technology Co., Ltd.; polyepoxysuccinic acid was purchased from Hubei Watson Chemical Technology Co., Ltd.; and polyquaternium-7 was purchased from Hubei Xinjiecheng Chemical Technology Co., Ltd.

[0020] Examples 1-3 provide a method for treating chemical wastewater.

[0021] Example 1 A method for treating chemical wastewater includes the following steps: S1. The chemical wastewater is introduced into the equalization tank, and the pH value of the chemical wastewater is adjusted to 6.5 with 0.5mol / L dilute hydrochloric acid. The temperature of the chemical wastewater is controlled at 25℃. The wastewater is filtered with a stainless steel filter screen with a pore size of 2mm to remove suspended impurities with a particle size ≥2mm. The wastewater is allowed to stand at room temperature and pressure for 30 minutes to obtain the pretreated wastewater. S2. Add modified industrial treatment agent to the pretreated wastewater, stir at 200 rpm for 40 min at room temperature, then add coagulant aid and continue stirring for 20 min. Allow to settle at room temperature and pressure to separate solids and liquids, obtaining supernatant and precipitated sludge. The precipitated sludge is dewatered and then disposed of harmlessly. The mass ratio of pretreated wastewater, modified industrial treatment agent and coagulant aid is controlled at 1000:3:1. The coagulant aid is anionic polyacrylamide. The preparation method of the modified industrial treatment agent is as follows: Modified water treatment adsorbent, polyaluminum chloride, activated carbon, and hydroxylated starch were added to a mixer in sequence. The mixture was stirred at 200 rpm at room temperature for 20 minutes. After stirring until homogeneous, a composite corrosion inhibitor was added. The mixture was stirred at 200 rpm at room temperature for 30 minutes. The mixture was then dried at 40°C for 10 hours and pulverized to a particle size of 80 mesh to obtain a modified industrial treatment agent. The composite corrosion inhibitor was composed of benzotriazole and aminotrimethylenephosphonic acid in a mass ratio of 1:1.2. The preparation method of the modified water treatment adsorbent includes the following preparation steps: Attapulgite and diatomaceous earth were mixed evenly and then subjected to calcination activation treatment. The calcination activation treatment specifically involved: first, heating to 300℃ at a heating rate of 8℃ / min and holding at that temperature for 2 hours; then heating to 420℃ at a heating rate of 2℃ / min and calcining for 3 hours; finally, allowing it to cool naturally to room temperature; and then pulverizing it through a 200-mesh sieve to obtain a composite mineral carrier. Deionized water was added to the composite mineral carrier, controlling the mass ratio of composite mineral carrier to deionized water to be 10:100, and stirring at a speed of 200 rpm. At pm, stir at room temperature for 10 min to disperse evenly. Then add hydroxyethylidene diphosphonic acid, polyepoxysuccinic acid and polyquaternium-7. Stir at 30℃ and 200 rpm for 2 h. Filter, wash with deionized water until the washing liquid is neutral, dry at 40℃ for 6 h, pulverize and pass through a 200-mesh sieve to obtain the modified water treatment adsorbent. Control the mass ratio of attapulgite, diatomaceous earth, hydroxyethylidene diphosphonic acid, polyepoxysuccinic acid and polyquaternium-7 to be 30:20:5:3:2.

[0022] S3. The supernatant was subjected to sand filtration using a double-layer filter media of quartz sand and anthracite, with a mass ratio of quartz sand to anthracite of 1:0.4 and a filtration rate of 6 m / h. After sand filtration, the supernatant was then subjected to ultraviolet light with an intensity of 40 μW / cm at room temperature. 2 The wastewater was disinfected with ultraviolet light at a wavelength of 254 nm for 15 minutes to obtain chemical wastewater that can be directly discharged or recycled.

[0023] Example 2 A method for treating chemical wastewater includes the following steps: S1. The chemical wastewater is introduced into the equalization tank, and the pH value of the chemical wastewater is adjusted to 7.0 with 0.8mol / L dilute hydrochloric acid. The temperature of the chemical wastewater is controlled at 30℃. The wastewater is filtered with a stainless steel filter screen with a pore size of 2mm to remove suspended impurities with a particle size ≥2mm. The wastewater is allowed to stand at room temperature and pressure for 35 minutes to obtain the pretreated wastewater. S2. Add modified industrial treatment agent to the pretreated wastewater, stir at 250 rpm for 50 min at room temperature, then add coagulant aid and continue stirring for 25 min. Allow to settle at room temperature and pressure to separate solids and liquids, obtaining supernatant and precipitated sludge. The precipitated sludge is dewatered and then disposed of harmlessly. The mass ratio of pretreated wastewater, modified industrial treatment agent and coagulant aid is controlled at 1000:5:1.5. The coagulant aid is anionic polyacrylamide. The preparation method of the modified industrial treatment agent is as follows: Modified water treatment adsorbent, polyaluminum chloride, activated carbon, and hydroxylated starch were added to a mixer in sequence. The mixture was stirred at 300 rpm at room temperature for 25 minutes. After the mixture was homogeneous, a composite corrosion inhibitor was added. The mixture was stirred at 300 rpm at room temperature for 35 minutes. The mixture was then dried at 50°C for 11 hours and pulverized to a particle size of 90 mesh to obtain a modified industrial treatment agent. The composite corrosion inhibitor was composed of benzotriazole and aminotrimethylenephosphonic acid in a mass ratio of 1:1.5. The preparation method of the modified water treatment adsorbent includes the following preparation steps: Attapulgite and diatomaceous earth were mixed evenly and then subjected to calcination activation treatment. The calcination activation treatment specifically involved: first, heating to 325℃ at a heating rate of 9℃ / min and holding at that temperature for 2.5 hours; then heating to 440℃ at a heating rate of 4℃ / min and calcining for 4 hours; finally, allowing it to cool naturally to room temperature, pulverizing it through a 250-mesh sieve to obtain a composite mineral carrier; deionized water was added to the composite mineral carrier, controlling the mass ratio of composite mineral carrier to deionized water at 15:110, and stirring at a speed of 250 rpm. At pm, stir at room temperature for 20 minutes to disperse evenly. Then add hydroxyethylidene diphosphonic acid, polyepoxysuccinic acid and polyquaternium-7. Stir at 38℃ and 250 rpm for 2.5 hours. Filter, wash with deionized water until the washing liquid is neutral, dry at 50℃ for 7 hours, pulverize and pass through a 250-mesh sieve to obtain the modified water treatment adsorbent. Control the mass ratio of attapulgite, diatomaceous earth, hydroxyethylidene diphosphonic acid, polyepoxysuccinic acid and polyquaternium-7 to be 35:25:7:4:3.

[0024] S3. The supernatant is subjected to sand filtration using a double-layer filter media of quartz sand and anthracite, with a mass ratio of quartz sand to anthracite of 1:0.5 and a filtration rate of 8 m / h. After sand filtration, the supernatant is then subjected to ultraviolet light with an intensity of 50 μW / cm at room temperature. 2 The wastewater was disinfected with ultraviolet light at a wavelength of 254 nm for 18 minutes to obtain chemical wastewater that can be directly discharged or recycled.

[0025] Example 3 A method for treating chemical wastewater includes the following steps: S1. The chemical wastewater is introduced into the equalization tank, and the pH value of the chemical wastewater is adjusted to 7.5 using 1mol / L sodium hydroxide solution. The temperature of the chemical wastewater is controlled at 35℃. The wastewater is filtered using a stainless steel filter screen with a pore size of 2mm to remove suspended impurities with a particle size ≥2mm. The wastewater is allowed to stand at room temperature and pressure for 40 minutes to obtain the pretreated wastewater. S2. Add modified industrial treatment agent to the pretreated wastewater, stir at 300 rpm for 60 min at room temperature, then add coagulant aid, continue stirring for 30 min, let it stand at room temperature and pressure to settle, and perform solid-liquid separation to obtain supernatant and precipitated sludge. The precipitated sludge is dewatered and then disposed of harmlessly. The mass ratio of pretreated wastewater, modified industrial treatment agent and coagulant aid is controlled at 1000:8:2. The coagulant aid is anionic polyacrylamide. The preparation method of the modified industrial treatment agent is as follows: Modified water treatment adsorbent, polyaluminum chloride, activated carbon, and hydroxylated starch were added to a mixer in sequence. The mixture was stirred at 400 rpm at room temperature for 30 minutes. After the mixture was homogeneous, a composite corrosion inhibitor was added. The mixture was stirred at 400 rpm at room temperature for 40 minutes. The mixture was then dried at 60°C for 12 hours and pulverized to a particle size of 100 mesh to obtain a modified industrial treatment agent. The composite corrosion inhibitor was composed of benzotriazole and aminotrimethylenephosphonic acid in a mass ratio of 1:1.8. The preparation method of the modified water treatment adsorbent includes the following preparation steps: Attapulgite and diatomaceous earth were mixed evenly and then subjected to calcination activation treatment. The calcination activation treatment specifically involved: first, heating to 350℃ at a heating rate of 10℃ / min and holding at that temperature for 3 hours; then heating to 450℃ at a heating rate of 5℃ / min and calcining for 5 hours; finally, allowing it to cool naturally to room temperature and pulverizing it through a 300-mesh sieve to obtain a composite mineral carrier; deionized water was added to the composite mineral carrier, controlling the mass ratio of composite mineral carrier to deionized water at 20:120, and stirring at a speed of 300 rpm. At pm, stir at room temperature for 30 min to disperse evenly. Then add hydroxyethylidene diphosphonic acid, polyepoxysuccinic acid and polyquaternium-7. Stir at 300 rpm at 45℃ for 3 h. Filter, wash with deionized water until the washing liquid is neutral, dry at 60℃ for 8 h, pulverize and pass through a 300-mesh sieve to obtain the modified water treatment adsorbent. Control the mass ratio of attapulgite, diatomaceous earth, hydroxyethylidene diphosphonic acid, polyepoxysuccinic acid and polyquaternium-7 to be 40:30:8:5:4.

[0026] S3. The supernatant is subjected to sand filtration using a double-layer filter media of quartz sand and anthracite, with a mass ratio of quartz sand to anthracite of 1:0.6 and a filtration rate of 10 m / h. After sand filtration, the supernatant is then subjected to ultraviolet light with an intensity of 60 μW / cm at room temperature. 2 The wastewater was disinfected with ultraviolet light at a wavelength of 254 nm for 20 minutes to obtain chemical wastewater that can be directly discharged or recycled.

[0027] Comparative Example 1 A method for treating chemical wastewater includes the following steps: S1. The chemical wastewater is introduced into the equalization tank, and the pH value of the chemical wastewater is adjusted to 6.5 with 0.5mol / L dilute hydrochloric acid. The temperature of the chemical wastewater is controlled at 25℃. The wastewater is filtered with a stainless steel filter screen with a pore size of 2mm to remove suspended impurities with a particle size ≥2mm. The wastewater is allowed to stand at room temperature and pressure for 30 minutes to obtain the pretreated wastewater. S2. Add modified industrial treatment agent to the pretreated wastewater, stir at 200 rpm for 40 min at room temperature, then add coagulant aid and continue stirring for 20 min. Allow to settle at room temperature and pressure to separate solids and liquids, obtaining supernatant and precipitated sludge. The precipitated sludge is dewatered and then disposed of harmlessly. The mass ratio of pretreated wastewater, modified industrial treatment agent and coagulant aid is controlled at 1000:3:1. The coagulant aid is anionic polyacrylamide. The preparation method of the modified industrial treatment agent is as follows: Modified water treatment adsorbent, polyaluminum chloride, activated carbon, and hydroxylated starch were added to a mixer in sequence. The mixture was stirred at 200 rpm at room temperature for 20 minutes. After stirring until homogeneous, a composite corrosion inhibitor was added. The mixture was stirred at 200 rpm at room temperature for 30 minutes. The mixture was then dried at 40°C for 10 hours and pulverized to a particle size of 80 mesh to obtain a modified industrial treatment agent. The composite corrosion inhibitor was composed of benzotriazole and aminotrimethylenephosphonic acid in a mass ratio of 1:1.2. The preparation method of the modified water treatment adsorbent includes the following preparation steps: Attapulgite and diatomaceous earth were mixed evenly and then subjected to calcination activation treatment. Specifically, the calcination activation treatment involved first heating to 300℃ at a rate of 8℃ / min and holding at that temperature for 2 hours, then heating to 420℃ at a rate of 2℃ / min and calcining for 3 hours. After natural cooling to room temperature, the mixture was pulverized and passed through a 200-mesh sieve to obtain a composite mineral carrier. Deionized water was added to the composite mineral carrier, maintaining a mass ratio of 10:100, and the mixture was stirred. The mixture was stirred at 200 rpm for 10 minutes at room temperature until it was evenly dispersed. Then, polyepoxysuccinic acid and polyquaternium-7 were added, and the mixture was stirred at 200 rpm for 2 hours at 30°C. The mixture was then filtered, washed with deionized water until the washing liquid was neutral, dried at 40°C for 6 hours, and pulverized through a 200-mesh sieve to obtain the modified water treatment adsorbent. The mass ratio of attapulgite, diatomaceous earth, polyepoxysuccinic acid, and polyquaternium-7 was controlled to be 30:20:5.5:4.5.

[0028] S3. The supernatant was subjected to sand filtration using a double-layer filter media of quartz sand and anthracite, with a mass ratio of quartz sand to anthracite of 1:0.4 and a filtration rate of 6 m / h. After sand filtration, the supernatant was then subjected to ultraviolet light with an intensity of 40 μW / cm at room temperature. 2The wastewater was disinfected with ultraviolet light at a wavelength of 254 nm for 15 minutes to obtain chemical wastewater that can be directly discharged or recycled.

[0029] Comparative Example 2 A method for treating chemical wastewater includes the following steps: S1. The chemical wastewater is introduced into the equalization tank, and the pH value of the chemical wastewater is adjusted to 6.5 with 0.5mol / L dilute hydrochloric acid. The temperature of the chemical wastewater is controlled at 25℃. The wastewater is filtered with a stainless steel filter screen with a pore size of 2mm to remove suspended impurities with a particle size ≥2mm. The wastewater is allowed to stand at room temperature and pressure for 30 minutes to obtain the pretreated wastewater. S2. Add modified industrial treatment agent to the pretreated wastewater, stir at 200 rpm for 40 min at room temperature, then add coagulant aid and continue stirring for 20 min. Allow to settle at room temperature and pressure to separate solids and liquids, obtaining supernatant and precipitated sludge. The precipitated sludge is dewatered and then disposed of harmlessly. The mass ratio of pretreated wastewater, modified industrial treatment agent and coagulant aid is controlled at 1000:3:1. The coagulant aid is anionic polyacrylamide. The preparation method of the modified industrial treatment agent is as follows: Modified water treatment adsorbent, polyaluminum chloride, activated carbon, and hydroxylated starch were added to a mixer in sequence. The mixture was stirred at 200 rpm at room temperature for 20 minutes. After stirring until homogeneous, a composite corrosion inhibitor was added. The mixture was stirred at 200 rpm at room temperature for 30 minutes. The mixture was then dried at 40°C for 10 hours and pulverized to a particle size of 80 mesh to obtain a modified industrial treatment agent. The composite corrosion inhibitor was composed of benzotriazole and aminotrimethylenephosphonic acid in a mass ratio of 1:1.2. The preparation method of the modified water treatment adsorbent includes the following preparation steps: Attapulgite and diatomaceous earth were mixed evenly and then subjected to calcination activation treatment. Specifically, the calcination activation treatment involved first heating to 300℃ at a rate of 8℃ / min and holding at that temperature for 2 hours, then heating to 420℃ at a rate of 2℃ / min and calcining for 3 hours. After natural cooling to room temperature, the mixture was pulverized and passed through a 200-mesh sieve to obtain a composite mineral carrier. Deionized water was added to the composite mineral carrier, maintaining a mass ratio of 10:100, and the mixture was stirred. The mixture was stirred at 200 rpm for 10 minutes at room temperature until it was evenly dispersed. Then, hydroxyethylidene diphosphonic acid and polyquaternium-7 were added. The mixture was stirred at 200 rpm for 2 hours at 30°C. The mixture was filtered, washed with deionized water until the washing liquid was neutral, dried at 40°C for 6 hours, and pulverized through a 200-mesh sieve to obtain the modified water treatment adsorbent. The mass ratio of attapulgite, diatomaceous earth, hydroxyethylidene diphosphonic acid, and polyquaternium-7 was controlled to be 30:20:6.5:3.5.

[0030] S3. The supernatant was subjected to sand filtration using a double-layer filter media of quartz sand and anthracite, with a mass ratio of quartz sand to anthracite of 1:0.4 and a filtration rate of 6 m / h. After sand filtration, the supernatant was then subjected to ultraviolet light with an intensity of 40 μW / cm at room temperature. 2 The wastewater was disinfected with ultraviolet light at a wavelength of 254 nm for 15 minutes to obtain chemical wastewater that can be directly discharged or recycled.

[0031] Comparative Example 3 A method for treating chemical wastewater includes the following steps: S1. The chemical wastewater is introduced into the equalization tank, and the pH value of the chemical wastewater is adjusted to 6.5 with 0.5mol / L dilute hydrochloric acid. The temperature of the chemical wastewater is controlled at 25℃. The wastewater is filtered with a stainless steel filter screen with a pore size of 2mm to remove suspended impurities with a particle size ≥2mm. The wastewater is allowed to stand at room temperature and pressure for 30 minutes to obtain the pretreated wastewater. S2. Add modified industrial treatment agent to the pretreated wastewater, stir at 200 rpm for 40 min at room temperature, then add coagulant aid and continue stirring for 20 min. Allow to settle at room temperature and pressure to separate solids and liquids, obtaining supernatant and precipitated sludge. The precipitated sludge is dewatered and then disposed of harmlessly. The mass ratio of pretreated wastewater, modified industrial treatment agent and coagulant aid is controlled at 1000:3:1. The coagulant aid is anionic polyacrylamide. The preparation method of the modified industrial treatment agent is as follows: Modified water treatment adsorbent, polyaluminum chloride, activated carbon, and hydroxylated starch were added to a mixer in sequence. The mixture was stirred at 200 rpm at room temperature for 20 minutes. After stirring until homogeneous, a composite corrosion inhibitor was added. The mixture was stirred at 200 rpm at room temperature for 30 minutes. The mixture was then dried at 40°C for 10 hours and pulverized to a particle size of 80 mesh to obtain a modified industrial treatment agent. The composite corrosion inhibitor was composed of benzotriazole and aminotrimethylenephosphonic acid in a mass ratio of 1:1.2. The preparation method of the modified water treatment adsorbent includes the following preparation steps: Attapulgite and diatomaceous earth were mixed evenly and then calcined and activated. The calcination and activation treatment was as follows: the temperature was first increased to 300℃ at a heating rate of 8℃ / min and held for 2 hours, then increased to 420℃ at a heating rate of 2℃ / min and calcined for 3 hours. After natural cooling to room temperature, the mixture was pulverized and passed through a 200-mesh sieve to obtain a composite mineral carrier. Deionized water was added to the composite mineral carrier, and the mass ratio of composite mineral carrier to deionized water was controlled at 10:100. The mixture was stirred at 200 rpm at room temperature for 10 minutes to disperse it evenly. Then, hydroxyethylidene diphosphonic acid and polyepoxysuccinic acid were added, and the mixture was stirred at 30℃ at 200 rpm for 2 hours. The mixture was filtered, washed with deionized water until the washing liquid was neutral, dried at 40℃ for 6 hours, and pulverized and passed through a 200-mesh sieve to obtain a modified water treatment adsorbent. The mass ratio of attapulgite, diatomaceous earth, hydroxyethylidene diphosphonic acid, and polyepoxysuccinic acid was controlled at 30:20:6:4.

[0032] S3. The supernatant was subjected to sand filtration using a double-layer filter media of quartz sand and anthracite, with a mass ratio of quartz sand to anthracite of 1:0.4 and a filtration rate of 6 m / h. After sand filtration, the supernatant was then subjected to ultraviolet light with an intensity of 40 μW / cm at room temperature. 2 The wastewater was disinfected with ultraviolet light at a wavelength of 254 nm for 15 minutes to obtain chemical wastewater that can be directly discharged or recycled.

[0033] Comparative Example 4 A method for treating chemical wastewater includes the following steps: S1. The chemical wastewater is introduced into the equalization tank, and the pH value of the chemical wastewater is adjusted to 6.5 with 0.5mol / L dilute hydrochloric acid. The temperature of the chemical wastewater is controlled at 25℃. The wastewater is filtered with a stainless steel filter screen with a pore size of 2mm to remove suspended impurities with a particle size ≥2mm. The wastewater is allowed to stand at room temperature and pressure for 30 minutes to obtain the pretreated wastewater. S2. Add modified industrial treatment agent to the pretreated wastewater, stir at 200 rpm for 40 min at room temperature, then add coagulant aid and continue stirring for 20 min. Allow to settle at room temperature and pressure to separate solids and liquids, obtaining supernatant and precipitated sludge. The precipitated sludge is dewatered and then disposed of harmlessly. The mass ratio of pretreated wastewater, modified industrial treatment agent and coagulant aid is controlled at 1000:3:1. The coagulant aid is anionic polyacrylamide. The preparation method of the modified industrial treatment agent is as follows: Modified water treatment adsorbent, polyaluminum chloride, activated carbon, and hydroxylated starch were added to a mixer in sequence. The mixture was stirred at 200 rpm at room temperature for 20 minutes. After stirring until homogeneous, a corrosion inhibitor was added, and the mixture was stirred at 200 rpm for 30 minutes. The mixture was then dried at 40°C for 10 hours and pulverized to a particle size of 80 mesh to obtain a modified industrial treatment agent. The corrosion inhibitor was aminotrimethylenephosphonic acid. The preparation method of the modified water treatment adsorbent includes the following preparation steps: Attapulgite and diatomaceous earth were mixed evenly and then subjected to calcination activation treatment. The calcination activation treatment specifically involved: first, heating to 300℃ at a heating rate of 8℃ / min and holding at that temperature for 2 hours; then heating to 420℃ at a heating rate of 2℃ / min and calcining for 3 hours; finally, allowing it to cool naturally to room temperature; and then pulverizing it through a 200-mesh sieve to obtain a composite mineral carrier. Deionized water was added to the composite mineral carrier, controlling the mass ratio of composite mineral carrier to deionized water to be 10:100, and stirring at a speed of 200 rpm. At pm, stir at room temperature for 10 min to disperse evenly. Then add hydroxyethylidene diphosphonic acid, polyepoxysuccinic acid and polyquaternium-7. Stir at 30℃ and 200 rpm for 2 h. Filter, wash with deionized water until the washing liquid is neutral, dry at 40℃ for 6 h, pulverize and pass through a 200-mesh sieve to obtain the modified water treatment adsorbent. Control the mass ratio of attapulgite, diatomaceous earth, hydroxyethylidene diphosphonic acid, polyepoxysuccinic acid and polyquaternium-7 to be 30:20:5:3:2.

[0034] S3. The supernatant was subjected to sand filtration using a double-layer filter media of quartz sand and anthracite, with a mass ratio of quartz sand to anthracite of 1:0.4 and a filtration rate of 6 m / h. After sand filtration, the supernatant was then subjected to ultraviolet light with an intensity of 40 μW / cm at room temperature. 2 The wastewater was disinfected with ultraviolet light at a wavelength of 254 nm for 15 minutes to obtain chemical wastewater that can be directly discharged or recycled.

[0035] Comparative Example 5 A method for treating chemical wastewater includes the following steps: S1. The chemical wastewater is introduced into the equalization tank, and the pH value of the chemical wastewater is adjusted to 6.5 with 0.5mol / L dilute hydrochloric acid. The temperature of the chemical wastewater is controlled at 25℃. The wastewater is filtered with a stainless steel filter screen with a pore size of 2mm to remove suspended impurities with a particle size ≥2mm. The wastewater is allowed to stand at room temperature and pressure for 30 minutes to obtain the pretreated wastewater. S2. Add modified industrial treatment agent to the pretreated wastewater, stir at 200 rpm for 40 min at room temperature, then add coagulant aid and continue stirring for 20 min. Allow to settle at room temperature and pressure to separate solids and liquids, obtaining supernatant and precipitated sludge. The precipitated sludge is dewatered and then disposed of harmlessly. The mass ratio of pretreated wastewater, modified industrial treatment agent and coagulant aid is controlled at 1000:3:1. The coagulant aid is anionic polyacrylamide. The preparation method of the modified industrial treatment agent is as follows: Modified water treatment adsorbent, polyaluminum chloride, activated carbon, and hydroxylated starch were added to a mixer in sequence. The mixture was stirred at 200 rpm at room temperature for 20 minutes. After stirring until homogeneous, a corrosion inhibitor was added, and the mixture was stirred at 200 rpm at room temperature for 30 minutes. The mixture was then dried at 40°C for 10 hours and pulverized to a particle size of 80 mesh to obtain a modified industrial treatment agent. The corrosion inhibitor was benzotriazole. The preparation method of the modified water treatment adsorbent includes the following preparation steps: Attapulgite and diatomaceous earth were mixed evenly and then subjected to calcination activation treatment. The calcination activation treatment specifically involved: first, heating to 300℃ at a heating rate of 8℃ / min and holding at that temperature for 2 hours; then heating to 420℃ at a heating rate of 2℃ / min and calcining for 3 hours; finally, allowing it to cool naturally to room temperature; and then pulverizing it through a 200-mesh sieve to obtain a composite mineral carrier. Deionized water was added to the composite mineral carrier, controlling the mass ratio of composite mineral carrier to deionized water to be 10:100, and stirring at a speed of 200 rpm. At pm, stir at room temperature for 10 min to disperse evenly. Then add hydroxyethylidene diphosphonic acid, polyepoxysuccinic acid and polyquaternium-7. Stir at 30℃ and 200 rpm for 2 h. Filter, wash with deionized water until the washing liquid is neutral, dry at 40℃ for 6 h, pulverize and pass through a 200-mesh sieve to obtain the modified water treatment adsorbent. Control the mass ratio of attapulgite, diatomaceous earth, hydroxyethylidene diphosphonic acid, polyepoxysuccinic acid and polyquaternium-7 to be 30:20:5:3:2.

[0036] S3. The supernatant was subjected to sand filtration using a double-layer filter media of quartz sand and anthracite, with a mass ratio of quartz sand to anthracite of 1:0.4 and a filtration rate of 6 m / h. After sand filtration, the supernatant was then subjected to ultraviolet light with an intensity of 40 μW / cm at room temperature. 2 The wastewater was disinfected with ultraviolet light at a wavelength of 254 nm for 15 minutes to obtain chemical wastewater that can be directly discharged or recycled.

[0037] Comparative Example 6 A method for treating chemical wastewater includes the following steps: S1. The chemical wastewater is introduced into the equalization tank, and the pH value of the chemical wastewater is adjusted to 6.5 with 0.5mol / L dilute hydrochloric acid. The temperature of the chemical wastewater is controlled at 25℃. The wastewater is filtered with a stainless steel filter screen with a pore size of 2mm to remove suspended impurities with a particle size ≥2mm. The wastewater is allowed to stand at room temperature and pressure for 30 minutes to obtain the pretreated wastewater. S2. Add modified industrial treatment agent to the pretreated wastewater, stir at 200 rpm for 40 min at room temperature, then add coagulant aid and continue stirring for 20 min. Allow to settle at room temperature and pressure to separate solids and liquids, obtaining supernatant and precipitated sludge. The precipitated sludge is dewatered and then disposed of harmlessly. The mass ratio of pretreated wastewater, modified industrial treatment agent and coagulant aid is controlled at 1000:3:1. The coagulant aid is anionic polyacrylamide. The preparation method of the modified industrial treatment agent is as follows: Modified water treatment adsorbent, polyaluminum chloride, activated carbon, and hydroxylated starch were added to a mixer in sequence. The mixture was stirred at 200 rpm at room temperature for 20 minutes. After stirring until homogeneous, a composite corrosion inhibitor was added. The mixture was stirred at 200 rpm at room temperature for 30 minutes. The mixture was then dried at 40°C for 10 hours and pulverized to a particle size of 80 mesh to obtain a modified industrial treatment agent. The composite corrosion inhibitor was composed of benzotriazole and aminotrimethylenephosphonic acid in a mass ratio of 1:1.2. The preparation method of the modified water treatment adsorbent includes the following preparation steps: Attapulgite and diatomaceous earth were mixed evenly and pulverized through a 200-mesh sieve to obtain a composite mineral carrier. Deionized water was added to the composite mineral carrier, and the mass ratio of composite mineral carrier to deionized water was controlled at 10:100. The mixture was stirred at 200 rpm at room temperature for 10 min to disperse it evenly. Then, hydroxyethylidene diphosphonic acid, polyepoxysuccinic acid, and polyquaternium-7 were added. The mixture was stirred at 200 rpm at 30°C for 2 h. The mixture was filtered, washed with deionized water until the washing liquid was neutral, dried at 40°C for 6 h, and pulverized through a 200-mesh sieve to obtain a modified water treatment adsorbent. The mass ratio of attapulgite, diatomaceous earth, hydroxyethylidene diphosphonic acid, polyepoxysuccinic acid, and polyquaternium-7 was controlled at 30:20:5:3:2.

[0038] S3. The supernatant was subjected to sand filtration using a double-layer filter media of quartz sand and anthracite, with a mass ratio of quartz sand to anthracite of 1:0.4 and a filtration rate of 6 m / h. After sand filtration, the supernatant was then subjected to ultraviolet light with an intensity of 40 μW / cm at room temperature. 2 The wastewater was disinfected with ultraviolet light at a wavelength of 254 nm for 15 minutes to obtain chemical wastewater that can be directly discharged or recycled.

[0039] Performance testing The performance of the chemical wastewater treated by the methods in Examples 1-3 and Comparative Examples 1-6 of this application was tested. The specific testing methods are as follows: Chemical oxygen demand (COD) removal rate: determined according to national standard GB / T 22597-2014 "Determination of Chemical Oxygen Demand in Reclaimed Water - Potassium Dichromate Method"; Ammonia nitrogen removal rate: The determination was carried out in accordance with the industry standard HJ 535-2009 "Determination of Ammonia Nitrogen in Water - Nessler's Reagent Spectrophotometric Method"; Total phosphorus removal rate: determined according to national standard GB / T 11893-1989 "Determination of total phosphorus in water quality - ammonium molybdate spectrophotometric method"; Determination of suspended solids in water: The determination was carried out in accordance with the national standard GB / T 11901-1989 "Determination of suspended solids in water - Gravimetric method"; The specific test results are shown in Table 1.

[0040] Table 1 Performance test results of the treated chemical wastewater in Examples 1-3 and Comparative Examples 1-6

[0041] As shown in Table 1, the chemical wastewater treatment methods provided in Examples 1-3 of this application have significant treatment advantages and practical value. The treated chemical wastewater exhibits chemical oxygen demand (COD) removal rates, ammonia nitrogen removal rates, and total phosphorus removal rates all exceeding 92%, with maximum removal rates of 96.5%, 94.6%, and 97.2%, respectively. The suspended solids content is 38-45 mg / L, meeting discharge standards. Compared to Comparative Examples 1-6, this application effectively solves the problem of poor treatment performance caused by single modified components or processes by optimizing the composition of the modified water treatment adsorbent and employing a composite corrosion inhibitor and composite mineral carrier calcination activation treatment process. The treated chemical wastewater can be directly discharged or recycled, combining environmental protection and economic efficiency, and is suitable for the efficient treatment of chemical wastewater.

[0042] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for treating chemical wastewater, characterized in that, Includes the following steps: S1. Introduce the chemical wastewater into the equalization tank, adjust the pH value of the chemical wastewater to 6.5-7.5, control the temperature of the chemical wastewater to 25-35℃, filter, and let it stand for 30-40 minutes to obtain the pretreated wastewater. S2. Add modified industrial treatment agent to the pretreated wastewater, stir and react for 40-60 minutes, then add coagulant aid, continue stirring for 20-30 minutes, let it stand to settle, and perform solid-liquid separation to obtain supernatant and precipitated sludge. The precipitated sludge is then dewatered and disposed of in a harmless manner. S3. After the supernatant is treated by sand filtration, it is then disinfected by ultraviolet light for 15-20 minutes to obtain chemical wastewater that can be directly discharged or recycled. The preparation method of the modified industrial treatment agent in step S2 is as follows: Modified water treatment adsorbent, polyaluminum chloride, activated carbon, and hydroxylated starch are added to a mixer in sequence and stirred evenly. Then, a composite corrosion inhibitor is added and stirred for another 30-40 minutes. After drying and pulverizing to a particle size of 80-100 mesh, the modified industrial treatment agent is obtained. The mass ratio of the modified water treatment adsorbent, polyaluminum chloride, activated carbon, hydroxylated starch and composite corrosion inhibitor is 20-30:25-35:15-20:10-15:3-6; The preparation method of the modified water treatment adsorbent includes the following preparation steps: Attapulgite and diatomaceous earth are mixed evenly, calcined and activated, naturally cooled to room temperature, pulverized and sieved to obtain a composite mineral carrier; deionized water is added to the composite mineral carrier, stirred and dispersed evenly, and then hydroxyethylidene diphosphonic acid, polyepoxysuccinic acid and polyquaternium-7 are added. The mixture is stirred and reacted at 30-45℃ for 2-3 hours, filtered, washed, dried, pulverized and sieved to obtain a modified water treatment adsorbent; The roasting activation treatment specifically involves: first, heating the temperature to 300-350℃ at a heating rate of 8-10℃ / min, holding the temperature for 2-3 hours, and then heating the temperature to 420-450℃ at a heating rate of 2-5℃ / min, and roasting for 3-5 hours. The mass ratio of attapulgite, diatomaceous earth, hydroxyethylidene diphosphonic acid, polyepoxysuccinic acid, and polyquaternium-7 is 30-40:20-30:5-8:3-5:2-4.

2. The chemical wastewater treatment method according to claim 1, characterized in that, The composite corrosion inhibitor is composed of benzotriazole and aminotrimethylenephosphonic acid in a mass ratio of 1:1.2-1.

8.

3. The chemical wastewater treatment method according to claim 1, characterized in that, In step S2, the mass ratio of pretreated wastewater, modified industrial treatment agent, and coagulant is 1000:3-8:1-2.

4. The chemical wastewater treatment method according to claim 1, characterized in that, The coagulant is one or more of anionic polyacrylamide, activated silica, and sodium alginate.

5. The chemical wastewater treatment method according to claim 1, characterized in that, The sand filtration process employs a double-layer filter media of quartz sand and anthracite, with a mass ratio of quartz sand to anthracite of 1:0.4-0.6 and a filtration rate of 6-10 m / h. The ultraviolet disinfection process uses an ultraviolet light intensity of 40-60 μW / cm². 2 The ultraviolet wavelength is 254nm.

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