Method for treating wastewater of super-high concentration water-soluble acrylate

Abstract

The application discloses a kind of treatment methods of super-high concentration water-soluble acrylate wastewater.The method comprises the following steps: adjusting the pH value of wastewater to 6-8;By standing precipitation and filtration, remove solid particles in wastewater;Add demulsifier polyaluminum chloride and polyacrylamide, destroy the stability of emulsion in wastewater, after demulsification, remove separated organic matter by centrifugal separation and filtration;After preliminary demulsification treatment, wastewater enters electrolytic catalytic oxidation system, and wastewater is efficiently electrolytic catalytic oxidized;After high-efficiency catalytic self-electrolysis treatment, wastewater is precipitated and filtered, and enters ozone catalytic oxidation system, and is subjected to ozone catalytic oxidation, and the effluent is discharged after reaching the standard.The process of the treatment method disclosed by the application is short, has high load resistance, high efficiency, small floor area, and no biochemical treatment system.The method has a COD removal rate of more than 99% for industrial wastewater with a concentration of 100,000 mg / L < COD < 200,000 mg / L.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a method for treating ultra-high concentration water-soluble acrylate wastewater. Background Technology

[0002] Water-soluble acrylates are a class of resins widely used in industrial production. Their wastewater contains high concentrations of organic matter such as COD and BOD, acidic substances, and toxic and harmful substances. Direct discharge of these wastewaters can cause environmental damage.

[0003] Adhesive wastewater is mostly water-soluble acrylate wastewater. This type of wastewater contains ester monomers, high-molecular-weight organic polymers, small amounts of initiators, emulsifiers, rosin resin tackifiers, etc., with a COD content typically exceeding 100,000 mg / L and high acidity, with a pH value as low as around 4.5. If this wastewater is discharged directly without treatment, it will cause serious pollution to the surrounding environment. Traditional methods for treating this type of adhesive industrial wastewater include incineration, catalytic wet oxidation, supercritical water oxidation, biodegradation, electrolysis, and membrane treatment. Among these, incineration is a mature and simple process, but it has the highest energy consumption; biodegradation has the best treatment effect, but its operation is very complex; electrolysis is relatively simple to operate, but its treatment effect is relatively poor, and the treated wastewater has a high COD content. Therefore, traditional wastewater treatment technologies can no longer meet the requirements of environmental protection, high efficiency, and energy conservation.

[0004] Hu Wenhu et al. used aluminum sulfate as a demulsifier and cationic PAM (polyacrylamide) as a flocculant to pretreat strongly alkaline waterborne acrylic adhesive industrial wastewater [COD (chemical oxygen demand) 37.90 g / L, pH 13.1] using coagulation. The pretreated wastewater was then further treated using reverse osmosis technology. The effects of demulsifier, flocculant, and stirring time on the wastewater pretreatment effect were investigated, and the optimal process parameters for the coagulation-reverse osmosis combined process were determined. The results showed that the optimal dosage of demulsifier at room temperature was 28.2 mg / L, the optimal dosage of flocculant was 0.24 g / mL, the optimal stirring time was 10 min, and the optimal reverse osmosis operating temperature was 30℃ and the operating pressure was 0.4 MPa. After treatment by the coagulation-reverse osmosis combined process, the COD value of the industrial wastewater decreased to 0.069 g / L, and the COD removal rate reached 99.8%. However, the wastewater treated by this process is highly alkaline, meaning that the process is not suitable for acidic acrylic ester wastewater. Furthermore, although the COD removal rate after demulsification reaches 96.2%, the COD of the effluent after coagulation and sedimentation is still 1430 mg / L. Finally, compared to the influent water quality of reverse osmosis, which generally requires COD < 15 mg / L, the reverse osmosis membrane in this process becomes clogged, making equipment operation and maintenance difficult. Summary of the Invention

[0005] To address the shortcomings and deficiencies of existing technologies, the present invention aims to provide a method for treating ultra-high concentration water-soluble acrylate wastewater. This treatment process is short, has strong load resistance, high efficiency, small footprint, and requires no biochemical treatment.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A method for treating ultra-high concentration water-soluble acrylate wastewater includes the following steps:

[0008] Step 1: Add a pH adjuster to the ultra-high concentration water-soluble acrylate wastewater to adjust the pH value of the wastewater to 6-8 to avoid corrosion of subsequent treatment equipment;

[0009] Step 2: Remove solid particles from wastewater through settling and filtration;

[0010] Step 3: Add demulsifiers polyaluminum chloride and polyacrylamide to disrupt the stability of the emulsion in the wastewater. After demulsification, remove the separated organic matter by centrifugation and filtration.

[0011] Step 4: The wastewater after preliminary demulsification treatment enters the electrolytic catalytic oxidation system for efficient electrolytic catalytic oxidation;

[0012] Step 5: After sedimentation and filtration, the wastewater treated by high-efficiency catalytic electrolysis enters the ozone catalytic oxidation system for ozone catalytic oxidation. The effluent is discharged after meeting the standards.

[0013] Preferably, the total COD content of the ultra-high concentration water-soluble acrylate wastewater in step 1 is 100,000 mg / L to 200,000 mg / L, and the pH value is less than 5.

[0014] More preferably, the ultra-high concentration water-soluble acrylate wastewater is adhesive paper coating and cleaning wastewater, which contains water-soluble acrylate and organic matter such as rosin resin.

[0015] Preferably, the pH adjustment in step 1 is performed using an alkaline substance, specifically sodium hydroxide or lime.

[0016] Preferably, the settling time in step 2 is 1 to 2 hours.

[0017] Preferably, the amount of polyaluminum chloride used in step 3 is 1-4 g / L, and the amount of polyacrylamide used is 5-10 mg / L; after adding the demulsifier, stir for 10-30 min.

[0018] More preferably, the polyacrylamide in step 3 is anionic polyacrylamide.

[0019] Preferably, the electrolytic catalytic oxidation system described in step 4 uses an iron-carbon micro-electrolysis packing material, and the electrolysis time is 4–6 hours. The self-electrolysis material is an iron-carbon micro-electrolysis packing material (preferably Φ6–14 mm, porosity 55%–65%, iron content ≥70%, carbon content ≥14%, specific surface area 1.2 m²). 2 / g~1.4m 2 / g), can generate an electrolytic voltage of approximately 1230mV in wastewater. Pure iron acts as the anode, while iron carbide and impurities become the cathode, resulting in an electrode reaction that breaks down the rings and chains of cyclic and long-chain macromolecular organics. It also breaks down the toxic functional groups of toxic and harmful organic pollutants, effectively removing color and heavy metal ions from wastewater. The Fe generated after iron discharge... 2+ Further release of electrons to oxidize into Fe 3+ When the pH is adjusted to 8-9, a flocculant Fe(OH)3 is formed, which has a strong adsorption-flocculation effect. This allows residual suspended solids, toxic organic matter, heavy metal ion hydrates and organic macromolecules in wastewater to be adsorbed, flocculated and separated, thus achieving wastewater purification.

[0020] Preferably, the ozone catalytic oxidation time in step 5 is 2-4 hours, and the ozone concentration during the ozone catalytic oxidation process is 400 mg / L-600 mg / L. Ozone is a very strong oxidant; adding ozone to industrial wastewater can improve its biodegradability and reduce its color. Ozone oxidation purifies water by directly participating in the reaction or generating highly oxidizing hydroxyl radicals to oxidize and decompose organic matter in the water. Ozone catalytic technology combines the strong oxidizing properties of ozone with the enrichment and catalytic characteristics of a catalyst, effectively solving the problem of incomplete degradation of organic matter and thus achieving better water treatment results.

[0021] Preferably, the COD content of the effluent in step 5 is less than 1000 mg / L.

[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0023] This invention provides an engineerable method for treating water-soluble acrylate wastewater that is short in process, has strong load resistance, high efficiency, small footprint, and no biochemical treatment system. This method is suitable for special and difficult industrial wastewater treatment processes with large load fluctuations within the wastewater treatment capacity range of 5 tons / day to 10 tons / day.

[0024] The method described in this invention is used to treat wastewater from the coating and cleaning of self-adhesive paper containing water-soluble acrylates and rosin resin. The concentration of this wastewater is between 100,000 mg / L and COD is between 200,000 mg / L, which is an ultra-high concentration industrial wastewater. The COD removal rate is as high as 99% or more. Attached Figure Description

[0025] Figure 1Photographs of the raw wastewater treated in Examples 1 and 2.

[0026] Figure 2 The relationship between the amount of demulsifier and the COD removal rate in Example 1 is shown.

[0027] Figure 3 This is a photograph of the wastewater after 4 hours of electrolytic catalytic oxidation in Example 2.

[0028] Figure 4 This is a photograph of the wastewater after further precipitation and filtration following 4 hours of electrolytic catalytic oxidation in Example 2. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto. All raw materials involved in the present invention can be purchased directly from the market. For process parameters not specifically specified, conventional techniques can be referred to.

[0030] Example 1: Demulsifier Dosage Experiment

[0031] 1. Wastewater quality

[0032] The water sample was taken from the coating and cleaning wastewater of a self-adhesive paper manufacturing company. The COD content was approximately 173,000 mg / L, the pH was approximately 4.6, the color was milky white, and it had a pungent odor. The wastewater mainly contained water-soluble acrylates and rosin resin. (See photo below.) Figure 1 As shown.

[0033] 2. Materials and Methods

[0034] Polyaluminum chloride (PAC) was prepared into a 10% (w / w) solution, and anionic polyacrylamide (PAM) was prepared into a 0.2% (w / w) solution.

[0035] 3. Experimental Procedure

[0036] First, adjust the pH of the wastewater to 8. Then, measure 50 mL of water sample into a round beaker and set up four experimental groups, adding different concentrations (1 g / L, 2 g / L, 3 g / L, 4 g / L) of PAC and PAM (10 mg / L). Use a six-stage mixer for stirring, with the following program: add PAC and stir rapidly for 2 minutes, then add PAM and maintain the original speed for 1 minute, then stir slowly for 10 minutes, and let it stand for 30 minutes to settle. After the experiment, take the supernatant 2 cm below the liquid surface to determine the COD of the treated water sample.

[0037] COD was determined using the potassium dichromate method and a water quality spectrophotometer.

[0038] 4. Results Analysis and Discussion

[0039] The COD removal rate when using PAC to treat this wastewater is as follows: Figure 2 As shown.

[0040] When the amount of PAC added was 1 g / L, 2 g / L, 3 g / L, and 4 g / L, the COD removal rates were 10.29%, 12.33%, 14.98%, and 24.28%, respectively.

[0041] It is evident that the COD removal rate increases with the increase of PAC dosage. The highest COD removal rate, 24.28%, was achieved when the PAC dosage was 4 g / L.

[0042] Example 2:

[0043] 1. Wastewater quality

[0044] The water sample was taken from the coating and cleaning wastewater of a self-adhesive paper manufacturing company. The COD content was about 173,000 mg / L, the pH was about 4.6, the color was milky white, and it had a pungent odor. The wastewater mainly contained water-soluble acrylates and rosin resin.

[0045] 2. Materials and Methods

[0046] Prepare a 10% (w / w) solution of polyaluminum chloride (PAC) and a 0.2% (w / w) solution of anionic polyacrylamide (PAM).

[0047] Iron electrodes as self-electrolysis materials

[0048] 3. Experimental Procedure

[0049] Step 1: Add sodium hydroxide to the wastewater to adjust the pH value to 8 to prevent corrosion of subsequent treatment equipment;

[0050] Step 2: Let the mixture stand for 1 hour to settle, then filter to remove solid particles from the waste liquid;

[0051] Step 3: Add polyaluminum chloride (4 g / L) and anionic polyacrylamide (10 mg / L) to destabilize the emulsion in the wastewater. Stir for 30 min to break the emulsion, then centrifuge and filter to remove the separated organic matter. The COD of the wastewater after the initial demulsification treatment is 122,800 mg / L and the pH is 5.5.

[0052] Step 4: After preliminary demulsification, the wastewater enters the electrolytic catalytic oxidation system for efficient catalytic self-electrolysis for 6 hours. This system uses iron-carbon micro-electrolysis packing material (φ6~14mm, porosity 55%~65%, iron content ≥70%, carbon content ≥14%, specific surface area 1.2m²). 2 / g~1.4m 2 / g);

[0053] Step 5: After the wastewater undergoes high-efficiency catalytic self-electrolysis treatment, it is precipitated and filtered, and then enters the ozone catalytic oxidation system for ozone catalytic oxidation for 4 hours; the ozone concentration is 400mg / L~600mg / L.

[0054] The effluent samples after 4 hours and 6 hours of high-efficiency catalytic self-electrolysis, and after 2 hours and 4 hours of ozone catalytic oxidation are shown in Table 1:

[0055] Table 1

[0056]

[0057] In this embodiment, the wastewater after 4 hours of highly efficient catalytic self-electrolysis is as follows: Figure 3 As shown, the wastewater after further sedimentation and filtration is as follows: Figure 4 As shown in Table 1 and the accompanying drawings, the method of the present invention can effectively treat high-concentration water-soluble acrylate wastewater.

[0058] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for treating ultra-high concentration water-soluble acrylate wastewater, characterized in that, Includes the following steps: Step 1: Add a pH adjuster to the ultra-high concentration water-soluble acrylate wastewater to adjust the pH value of the wastewater to 6-8; the total COD content of the ultra-high concentration water-soluble acrylate wastewater is 100,000 mg / L-200,000 mg / L, and the pH value is less than 5; the ultra-high concentration water-soluble acrylate wastewater is self-adhesive paper coating and cleaning wastewater; Step 2: Remove solid particles from wastewater through settling and filtration; Step 3: Add demulsifiers polyaluminum chloride and polyacrylamide to disrupt the stability of the emulsion in the wastewater. After demulsification, remove the separated organic matter by centrifugation and filtration. Step 4: The wastewater after preliminary demulsification treatment enters the electrolytic catalytic oxidation system for efficient electrolytic catalytic oxidation; the electrolysis time is 4~6 hours. Step 5: After sedimentation and filtration, the wastewater treated by high-efficiency catalytic electrolysis enters the ozone catalytic oxidation system for ozone catalytic oxidation. The ozone catalytic oxidation time is 2~4 hours, and the ozone concentration is 400 mg / L~600 mg / L. The effluent is discharged after meeting the standards.

2. The processing method according to claim 1, characterized in that, The pH adjuster mentioned in step 1 is an alkaline substance, specifically sodium hydroxide or lime.

3. The processing method according to claim 1, characterized in that, The settling time in step 2 is 1-2 hours.

4. The processing method according to claim 1, characterized in that, In step 3, the amount of polyaluminum chloride used is 1~4 g / L, and the amount of polyacrylamide used is 5~10 mg / L; after adding the demulsifier, stir for 10~30 min.

5. The processing method according to claim 1, characterized in that, The electrolytic catalytic oxidation system described in step 4 uses iron-carbon micro-electrolysis packing material.

6. The processing method according to claim 5, characterized in that, The parameters of the iron-carbon micro-electrolysis filler are: α6~14mm, porosity 55%~65%, iron content ≥70%, carbon content ≥14%, and specific surface area 1.2m². 2 / g~1.4m 2 / g.

7. The processing method according to claim 1, characterized in that, The COD content of the effluent in step 5 is less than 1000 mg / L.

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