CN115947493A - Fluorine chemical resin dispersion water treatment process - Google Patents

Abstract

The invention discloses a process for treating fluorine chemical resin dispersion water, which belongs to the technical field of waste water treatment; it comprises the following steps: S1 sequentially processes and filters the chemical resin dispersion water to obtain a pretreatment liquid; S2 performs the pretreatment liquid is subjected to ultrafiltration treatment to obtain ultrafiltrate; S3 carries out RO treatment to the ultrafiltrate to obtain treated water; the chemical resin dispersion water treatment process of the present invention includes Fenton treatment, filtration+ultrafiltration treatment+RO membrane Treatment, the treatment process is simple and low cost, and can be widely used in the treatment process of chemical resin dispersion water. After this process, the removal rate of SS in the chemical resin dispersion water can be 100%, and the ammonia nitrogen content in it can be reduced to 100%. Control at 10%, while the recovery rate of dispersed water is ≥70%.

Description

A fluorine chemical resin dispersion water treatment process

technical field

The invention relates to the technical field of chemical wastewater treatment, in particular to a fluorine chemical resin dispersion water treatment process.

Background technique

In the fluorine chemical industry, various fluororesin products are widely produced, such as PTFE dispersion resin, PTFE concentrated dispersion liquid, PTFE suspension resin, etc., and a large amount of resin dispersion water will be generated during the production process. The resin dispersion water contains a large amount of SS (suspended solids concentration). However, due to the presence of surfactants, the resin dispersion water is stable, and the colloidal substances in it are difficult to fully coagulate and thus difficult to remove. At the same time, the resin dispersion The ammonia nitrogen content of the water is also extremely high, which leads to the fact that the resin dispersion water does not meet the acceptance standards of the sewage treatment plant in the park. Therefore, the resin separation water needs to be treated before it is transported to the sewage treatment plant.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art and provide a fluorine chemical resin dispersion water treatment process to at least achieve the purpose of reducing the concentration of SS and ammonia nitrogen in the resin dispersion water and improving the recovery rate.

The purpose of the present invention is achieved through the following technical solutions:

A fluorine chemical resin dispersion water treatment process, comprising the steps of:

S1 The chemical resin dispersion water is sequentially treated by Fenton and filtered to obtain the pretreatment liquid;

S2 performing ultrafiltration on the pretreatment liquid to obtain an ultrafiltrate;

S3 subjecting the ultrafiltrate to RO treatment to obtain treated water.

As some possible implementations of the present application, in the step S1, aeration and stirring are used during the Fenton treatment.

As some possible embodiments of the present application, in the step S1, the Fenton reagent in the Fenton treatment is hydrogen peroxide and ferrous sulfate, wherein the mass ratio of hydrogen peroxide and ferrous sulfate is 1-3:1.

As some possible embodiments of the present application, the mass ratio of hydrogen peroxide to ferrous sulfate is 1:1.

As some possible implementations of the present application, in the step S1, a filter with a filter pore diameter of less than 100 microns is used for filtering.

As some possible implementations of the present application, in the step S2, the pH of the influent during the ultrafiltration treatment is 5.5-6.

As some possible implementations of the present application, in the step S2, the pH of the influent during the ultrafiltration treatment is 5.5.

As some possible implementations of the present application, in the step S3, the pH of the influent during the RO treatment is 5.5-6.

As some possible implementations of the present application, in the step S3, the pH of the influent during the RO treatment is 5.5.

The beneficial effects of the present invention are:

The chemical resin dispersion water treatment process of the present invention includes Fenton treatment, filtration+ultrafiltration treatment+RO membrane treatment, the treatment process is simple, the cost is low, and can be widely used in the treatment process of chemical resin dispersion water. After the process treatment, The removal rate of SS in the chemical resin dispersion water can be 100%, the ammonia nitrogen content in it can be controlled at 10mg/l, and the recovery rate of the dispersion water is ≥70%, which meets the acceptance standard of the sewage treatment plant in the park.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of this application.

In the fluorine chemical industry, various fluororesin products are widely produced, such as PTFE dispersion resin, PTFE concentrated dispersion liquid, PTFE suspension resin, etc., and a large amount of resin dispersion water will be generated during the production process. The resin dispersion water contains a large amount of SS, but the resin dispersion water contains surfactants, etc., resulting in the stability of the resin dispersion water, which makes it difficult to fully coagulate and remove the colloidal substances in the resin dispersion water. At the same time, the resin dispersion water The ammonia nitrogen content is also extremely high, which leads to the fact that the resin dispersion water does not meet the acceptance standards of the sewage treatment plant in the park. Therefore, the resin separation water needs to be treated before it is transported to the sewage treatment plant.

Based on this, the present invention provides a kind of fluorine chemical resin dispersion water treatment process, comprises the following steps:

S1 The chemical resin dispersion water is sequentially treated by Fenton and filtered to obtain the pretreatment liquid;

S2 performing ultrafiltration on the pretreatment liquid to obtain an ultrafiltrate;

S3 subjecting the ultrafiltrate to RO treatment to obtain treated water.

In the above scheme, the Fenton treatment method is first used to destroy the stability of the dispersed water to the greatest extent, so that the stable colloidal substances in the dispersed water form a large amount of suspended solids, and then the suspended solids and colloidal substances are removed by filtration. The pretreatment solution was obtained, and the pretreatment was passed through the aeration experiment, and it was found that the solution was still clear and transparent, indicating that there were very few suspended solids and colloidal substances in the dispersed water after Fenton treatment and filtration treatment, and then indicating that the SS in it had been maximized. removal, to avoid impact on the permeability of the ultrafiltration membrane during the subsequent ultrafiltration treatment, resulting in adverse phenomena such as membrane plugging; thereafter, the pretreatment liquid is treated by the ultrafiltration membrane, and some of the unremoved particles in step S1 can be removed. Suspended solids, colloidal substances, and impurities such as suspended solids and colloids generated by adding chemicals during the Fenton treatment process are effectively removed to ensure the stable operation of the subsequent expensive RO membrane; finally, reverse osmosis treatment is performed through the R0 membrane to Reduce ammonia nitrogen content, salinity in water and completely remove SS. After the resin dispersion water treated by the above scheme, SS is completely removed, the ammonia nitrogen content is controlled at about 10mg/l, and the recovery rate of dispersion water is ≥70%, which meets the acceptance standard of the sewage treatment plant in the park.

In order to further improve the removal efficiency of SS in the chemical resin dispersion water, as some possible implementations of the present application, in the step S1, aeration and stirring are used during the Fenton treatment. During the Fenton treatment, the stirring method plays an important role in the destabilization of the colloids in the dispersed water. By adopting the aeration and stirring method, the dissolved oxygen content in the water can be effectively increased, and then cooperate with the Fenton reagent to exert the oxidation effect, and at the same time, it can increase Disperse the mixing effect of water and medicine to speed up the reaction.

In order to further improve the removal efficiency of SS in chemical resin dispersion water, as some possible embodiments of the present application, the Fenton reagent in the Fenton treatment and the reagent consumption are limited, that is, in the step S1, the Fenton in the Fenton treatment The ton reagent is hydrogen peroxide and ferrous sulfate, wherein the mass ratio of hydrogen peroxide and ferrous sulfate is 1-3:1.

In the Fenton treatment, the cost and effectiveness need to be considered. The combination of hydrogen peroxide and ferrous sulfate is the most basic combination in the Fenton reagent. However, in the Fenton treatment, when the characteristics of the dispersed water itself are fixed, hydrogen peroxide The quality relationship with ferrous sulfate is very important. If too much hydrogen peroxide is added, it will cause waste of oxidant, and it will also float tetrafluoroethylene resin and other substances in the dispersed water. If too much ferrous sulfate is added, the colloid will not be easy to suspend, and even Discoloration occurs. Through a large number of experiments, the present invention shows that when the mass ratio of hydrogen peroxide and ferrous sulfate is 1-3:1, the reaction efficiency is high and the SS removal efficiency is the highest.

In order to further improve the removal efficiency of SS in chemical resin dispersion water and reduce the conductivity in dispersion water, as some possible embodiments of the application, the amount ratio between Fenton's reagents is limited, that is, the quality of the hydrogen peroxide and ferrous sulfate The ratio is 1:1. In actual experiments, when the mass ratio of hydrogen peroxide and ferrous sulfate is 1-3:1, it can play a significant role in removing SS. However, different mass ratios will lead to large differences in the conductivity of the dispersed water after treatment. , if the conductivity of the dispersed water is much greater than the value originally designed for the ultrafiltration membrane module system, it will cause the ultrafiltration membrane equipment to reduce the water pressure, which will lead to a decrease in the water production. In the present invention, by limiting the mass ratio of hydrogen peroxide to ferrous sulfate to be 1:1, the conductivity of the ultra-ultrafiltration membrane influent can be controlled at about 5000us/cm, so as to ensure the stable operation of the ultra-filtration membrane and increase the water production. The mass ratio of ferrous sulfate to ferrous sulfate is 3:1, then the conductivity of dispersed water after Fenton is about 8000us/cm, and the water production rate is relatively reduced.

In order to further improve the removal efficiency of SS in chemical resin dispersion water, as some possible implementation methods of the present application, the filter pore diameter during filtration is limited, that is, in the step S1, filter with a filter pore diameter less than 100 microns is used for filtration. filter. By limiting the pore diameter of the filter, the suspended matter in it can be removed to the greatest extent, thereby improving the SS removal rate.

In order to further improve the removal efficiency of SS in chemical resin dispersion water, as some possible embodiments of the present application, the influent pH during ultrafiltration treatment is limited, that is, in the step S2, the influent pH during ultrafiltration treatment is 5.5-6. During the ultrafiltration treatment, if the pH is high, there are still some flocculated impurities in the dispersed water, such as ferric hydroxide colloid, which will adversely affect the flux of the ultrafiltration membrane during the ultrafiltration treatment, and even cause membrane blocking. . If the pH is too low, the hydrophobicity of the organic matter remaining in the dispersion water will increase, which will cause a certain degree of membrane fouling. By limiting the pH to 5.5-6, the fouling of the ultrafiltration membrane can be reduced, and at the same time, the flux of the ultrafiltration membrane can be ensured to be stable.

In order to further improve the removal efficiency of SS in chemical resin dispersion water, as some possible embodiments of the present application, the influent pH during ultrafiltration treatment is limited, that is, in the step S2, the influent pH during ultrafiltration treatment is 5.5.

In order to further improve the removal efficiency of ammonia nitrogen in chemical resin dispersion water, as some possible embodiments of the present application, the influent water during RO treatment is limited, that is, in the step S3, the pH of the influent water during RO treatment is 5.5-6 . In the actual operation of the RO membrane, the pH of the feed water has a great influence on the ammonia nitrogen of the produced water. When the pH of the feed water is 5.5-6, the ammonia nitrogen content in the produced water is ≤25mg/l.

In order to further improve the removal efficiency of ammonia nitrogen in the chemical resin dispersion water, as some possible embodiments of the present application, the influent water during RO treatment is limited, that is, in the step S3, the pH of the influent water during RO treatment is 5.5. When the influent pH is 5.5, the ammonia nitrogen content of the product water can be controlled at about 10mg/l.

Below in conjunction with specific embodiment, the treatment process of resin dispersion water described in the present application is further described in detail;

It is worth noting that: various raw materials in the embodiment are commercially available products;

Example 1

S1 Take 2L of chemical resin dispersion water, adjust the pH to 3 with dilute sulfuric acid, then add hydrogen peroxide (30% hydrogen peroxide mass fraction) with 1‰ dispersion water quality and 1‰ ferrous sulfate dispersion water quality, and use exposure Stir in the air stirring mode, after the reaction is finished, adjust the pH of the dispersed water to be neutral, and then filter it with a bag filter with a pore size of 100 μm to obtain a pretreatment solution;

S2 adjusts the pH of the pretreatment solution to 5.5 with sulfuric acid, and then performs ultrafiltration to obtain an ultrafiltrate;

S3 adjusts the pH of the ultrafiltrate to 5.5 with sulfuric acid, and then performs RO treatment to obtain treated water.

Example 2

S1 Take 2L of chemical resin dispersion water, adjust the pH to 3 with dilute sulfuric acid, then add hydrogen peroxide (30% hydrogen peroxide mass fraction) with dispersion water quality of 2‰ and ferrous sulfate with dispersion water quality of 1‰, and use exposure Stir in the air stirring mode, after the reaction is finished, adjust the pH of the dispersed water to be neutral, and then filter it with a bag filter with a pore size of 100 μm to obtain a pretreatment solution;

S2 adjusts the pH of the pretreatment solution to 5.5 with sulfuric acid, and then performs ultrafiltration to obtain an ultrafiltrate;

S3 adjusts the pH of the ultrafiltrate to 5.8 with sulfuric acid, and then performs RO treatment to obtain treated water.

Comparative example 1

Compared with Example 1, the pH is not adjusted before the supertreatment in step S2, and the remaining steps and parameters are the same as in Example 1.

Comparative example 2

Compared with Example 1, the steps in step S1 have been changed, and the Fenton + filtration process has been changed to the "aeration + flocculation" method. The specific steps are as follows:

S1 Add chemical resin dispersion water into the vat, then adjust the pH of the raw water to be neutral and aerate for 1 hour, then add 5‰ PAC solution (flocculation), filter after sufficient flocculation; continue aeration according to the previous method after filtration + Flocculation, continue aeration after filtration + Flocculation, filtration to obtain pretreatment liquid.

All the other steps and parameters are the same as in Example 1.

Test case

Test Example 1 compares the effect of removing SS in step S1 in Example 1 and Comparative Example 2.

In this test example, the chemical resin dispersion water used in Example 1 and Comparative Example 1 all came from the same batch, and the indicators of the chemical resin dispersion water are shown in Table 1.

Table 1 Chemical resin dispersion water index

Water sample name resin dispersion water pH (dimensionless) 8.0 SS(mg/l) 67mg/L Ammonia nitrogen 447mg/L fluorine 3.4mg/L Conductivity 3800us/cm COD (mg/L) 14mg/L sensory description Raw water has floating matter, white turbidity

Get the pretreatment liquid among the embodiment 1, find that its water quality is clear, carry out aeration treatment to it afterwards, find that there is no suspended matter to produce again, illustrate thus that Fenton process can effectively handle the suspended matter in resin dispersion water; Wherein , the conductivity of the pretreatment solution in Example 1 is only 5000us/cm.

In Comparative Example 2, a white suspension was produced during the three aeration + flocculation processes. At the same time, the pretreatment liquid in Comparative Example 2 was taken and aerated, and it was found that suspended matter was still produced, which shows that aeration + flocculation The method can not completely remove the white suspended matter in the water, and then embodies the remarkable effect that Fenton can achieve; wherein, the conductivity of the pretreatment solution in Comparative Example 2 is 4500us/cm, which is compared with the conductivity in Example 1 near.

Test example 2 comparative example 1, comparative example 1 and the ultrafiltration membrane plugging situation in comparative example 2

The parameters of the resin dispersion water used in this test example were the same as those in Test Example 1.

1. According to the method of S1 in Comparative Example 2, 5 groups of parallel experiments were carried out, and then the obtained 5 groups of pretreatment liquids were subjected to ultrafiltration treatment, and the parameters in the ultrafiltration treatment were shown in Table 2.

Among them, groups 1-4 are continuous experiments, and group 5 is an experiment after cleaning, in order to check the fouling situation of ultrafiltration and the effect of cleaning and recovery, and to prevent deviations in experimental results. The ultrafiltration was cleaned before the experiment.

Table 2

It can be seen from Table 2 that the output of ultrafiltration is in a downward trend, indicating that the water treated by aeration + flocculation is likely to cause fouling and clogging of ultrafiltration membranes; in addition, the data in Table 2 are analyzed as follows: ①The first group of ultrafiltration membranes pass through The flow rate was low, which was related to the low temperature of the day and the failure of the equipment to be cleaned; ②The second group of ultrafiltration was a normal flux at 18.6°C; ③The ultrafiltration was backwashed before the third group, and the membrane flux The decrease is slight, which is within the error range, because the on-site timing and the volume of water samples are slightly deviated; ④The fourth group did not backwash the ultrafiltration before the start, and the membrane flux decreased by about 20%; ⑤The fifth group underwent backwashing After cleaning and acid-base cleaning, the flux has recovered, but it still drops significantly.

2. according to the method for S1 in embodiment 1, embodiment 1 is done 3 groups of parallel tests, comparative example 1 is done 1 group of tests, carries out ultrafiltration process according to S2 thereafter, the parameter of ultrafiltration process is as shown in table 3, with Check the fouling of ultrafiltration after Fenton. Note: Only water backwashing is performed after each set of tests, because in engineering, water is normally produced for about 1 hour and then backwashed for 3 minutes.

table 3

Can know by table 3: the membrane flux of 3 groups of experiments in the embodiment 1 and the experiment in the comparative example 1 does not change much when ultrafiltration starts and ends; 3 groups of experiments in the embodiment 1 all rise to some extent, comparative example The membrane flux in 1 drops slightly; The reason for the rise of 3 groups of experiments in embodiment 1 is that along with the prolongation of membrane experiment time, the temperature of membrane device rises gradually, has increased membrane flux, and amphoteric colloid ( Ferric hydroxide, aluminum hydroxide) are difficult to exist, and membrane fouling is less; And the reason that comparative example 1 membrane flux declines is that pH is not adjusted, causes still part flocculation impurity (as ferric hydroxide colloid) to cause; Through table 2 It can be seen that, before the ultrafiltration treatment, the Fenton oxidation treatment is carried out, and there is basically no fouling in the ultrafiltration treatment.

Through this test, it can be seen that after the raw water is treated with ultrafiltration + aeration, there are still many suspended solids, and it is easy to cause fouling to the ultrafiltration membrane if it is directly used for ultrafiltration treatment; after the raw water is treated with Fenton, there is almost no Suspended matter, using it for ultrafiltration treatment, there is basically no fouling, which reflects the remarkable effect of Fenton treatment on SS removal.

Test example 3 verifies the effect of the solution of the present invention in treating dispersion water.

After comparing the processes of S1 and S2 in test examples 1 and 2, this test example directly carries out the comparison of S3, and S3 is also the last step of the scheme of the present invention, and the parameters of water production in this step can test the feasibility of the scheme of the present invention and superiority.

Do 4 groups of experiments according to the method of embodiment 1, do 1 group of experiments according to the method of embodiment 2, wherein, the parameter of the resin dispersion water (being the raw water in table 4) in every group of experiments is different, and concrete parameter is as shown in table 4 Show:

Table 4 Comparison of relevant parameters of RO membrane treatment

It can be seen from Table 4 that during the 4 groups of experiments in Example 1 and the RO membrane treatment process in Example 2, the RO membrane flux did not change much, indicating that after ultrafiltration, the water caused little fouling to the RO membrane; , the fourth group of experiments in Example 1 was cleaned, and the membrane flux after cleaning can be restored to the highest level, indicating that the fouling caused by it can be effectively removed. In addition, through the 5 sets of experimental data in Table 3, it can be known that the recovery rate of dispersion water is ≥76%. Because the difference between Example 1 and Example 2 is that the pH of the RO membrane feed water is different, it can be seen from Table 3 that when the feed water pH is 5.8, the ammonia nitrogen content in the product water is 20.7 mg/l; when the feed water pH is stable at At 5.5, the ammonia nitrogen in the produced water can be stabilized at about 10mg/l, which reflects the influence of pH on the removal rate of ammonia nitrogen; further, after the process of the present invention, there is no SS in the dispersed water, which means that no SS is detected , indicating that the removal rate is 100%.

To sum up: through test examples 1-3, it can be seen that the dispersion water can be effectively treated by using the process of Fenton + ultrafiltration + RO, so that the ammonia nitrogen of the produced water can be stabilized at 10mg/l, and the SS removal rate is 100%, which meets the customer's requirements , At the same time, the RO recovery rate is greater than 70%, the flux of ultrafiltration and RO membranes is large, which fully meets the design requirements, the fouling of the membrane is effectively controlled, and it can run stably for a long time; at the same time, the cost of dosing is low, and engineering treatment can be carried out.

The above descriptions are only preferred embodiments of the present invention, and it should be understood that the present invention is not limited to the forms disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and Modifications can be made within the scope of the ideas described herein, by virtue of the above teachings or skill or knowledge in the relevant art. However, changes and changes made by those skilled in the art do not depart from the spirit and scope of the present invention, and should all be within the protection scope of the appended claims of the present invention.

Claims (9)

1. a fluorine chemical resin dispersion water treatment process, is characterized in that, comprises the steps: S1 The chemical resin dispersion water is sequentially treated by Fenton and filtered to obtain the pretreatment liquid; S2 performing ultrafiltration on the pretreatment liquid to obtain an ultrafiltrate; S3 subjecting the ultrafiltrate to RO treatment to obtain treated water. 2. A fluorine chemical resin dispersion water treatment process according to claim 1, characterized in that, in the step S1, aeration and stirring are used in the Fenton treatment process. 3. A kind of fluorine chemical resin dispersion water treatment process according to claim 1, is characterized in that, in described step S1, the Fenton's reagent in the Fenton treatment is hydrogen peroxide and ferrous sulfate, wherein, hydrogen peroxide and ferrous sulfate The mass ratio of iron is 1-3:1. 4. A kind of fluorine chemical resin dispersion water treatment process according to claim 3, is characterized in that, the mass ratio of described hydrogen peroxide and ferrous sulfate is 1:1. 5. A fluorine chemical resin dispersion water treatment process according to claim 1, characterized in that, in the step S1, a filter with a filter pore diameter of less than 100 microns is used for filtering. 6. A fluorine chemical resin dispersion water treatment process according to claim 1, characterized in that, in the step S2, the pH of the influent during the ultrafiltration treatment is 5.5-6. 7. A fluorine chemical resin dispersion water treatment process according to claim 6, characterized in that, in the step S2, the pH of the influent during the ultrafiltration treatment is 5.5. 8. A fluorine chemical resin dispersion water treatment process according to claim 1, characterized in that, in the step S3, the pH of the incoming water during the RO treatment is 5.5-6. 9. A fluorine chemical resin dispersion water treatment process according to claim 1, characterized in that, in the step S3, the pH of the influent during RO treatment is 5.5.