CN117756342B - System and method for efficiently removing bisphenol A and fulvic acid from surface water sources - Google Patents

Abstract

The present invention discloses a system for efficiently removing bisphenol A and FA from surface water sources, including a mixed reaction precipitation unit for removing tiny particles from surface water, a water outlet pipe of the mixed reaction precipitation unit connected to a reagent adaptor adding unit, the reagent adaptor adding unit for adding reagents to water treated by the mixed reaction precipitation unit, the water with the reagents added flows into a filter unit, and under the action of a filter material provided in the filter unit, bisphenol A and FA in the water are removed, the filter unit is connected to a disinfection unit, and the disinfection unit is used to sterilize and disinfect the surface water. The present invention also discloses a method for removing bisphenol A and FA using the above system. The method of the present invention reasonably and effectively integrates multiple technologies such as ferrate reagent adaptor addition, chemical assisted oxidation, interception filtration, chemical adsorption, chemical contact catalytic oxidation, etc., and can effectively achieve efficient removal of bisphenol A and FA from surface water sources.

Description

System and method for efficiently removing bisphenol A and fulvic acid from surface water sources

Technical Field

The present invention belongs to the technical field of drinking water treatment, and in particular relates to a system for efficiently removing bisphenol A and fulvic acid (FA) in surface water sources. The present invention also relates to a method for removing bisphenol A and FA in surface water sources using the system.

Background technique

As an environmental hormone, bisphenol A is a type of diphenylalkane/bisphenol compound and is commonly used in the production of polycarbonate plastics and epoxy resins. Bisphenol A is mainly derived from industrial production and is produced through a chemical synthesis process. It is generated by the condensation reaction of phenol and acetone. As humans increasingly use fossil fuels and synthesize various chemical products, groundwater across the country has been polluted by phenolic pollutants to varying degrees, and organic pollutants such as phenols discharged into wastewater are also difficult to degrade naturally. In addition, bisphenol A is an endocrine disruptor that can simulate hormones in the human body, may interfere with the normal function of the endocrine system, and affect the reproductive system, metabolism, immune system and other physiological processes. In recent years, the issue of natural organic matter (NOM) in water resources has also received widespread attention. Humus, as a representative of NOM, is widely present in nature. Fulvic acid (FA) is mainly distributed in water sources such as lakes and rivers. It can react with some metal ions, pesticides or halogenated hydrocarbons to form carriers of these compounds. In particular, FA will be lost due to rainfall and runoff. The loss of FA will reduce soil fertility and cause dissolved organic matter pollution in water bodies. FA will also increase the risk of cancer in humans and lead to the birth of deformed infants.

Experimental research and practical production at home and abroad have shown that: organic polluted water can remove most of the large-particle organic matter and a small part of the small-particle organic matter through the conventional flocculation-sedimentation-filtration-disinfection process, while the large-particle organic matter only accounts for 20% to 30% of the total organic matter. The removal rate of organic matter in water characterized by bisphenol A and FA is 20% to 30%. Due to the variety, small particle size and complex structure of soluble organic matter (such as bisphenol A and FA) in water, most organic matter cannot be removed by traditional processes. Therefore, the research on the removal of bisphenol A and FA is mainly focused on deep treatment, mainly including adsorption technology, membrane treatment technology and biological treatment technology. Although adsorption technology has high removal efficiency and simple operation, the quality of the effluent after adsorption saturation is difficult to guarantee, and the adsorption material needs to be replaced and regenerated regularly. Although membrane separation technology has a good removal effect, the operation and maintenance cost is high and the membrane is easily contaminated. The biological treatment process has a low operating cost, but the startup cycle is long and it is easily affected by low temperature.

In summary, the research and development of low-cost and efficient water treatment processes for high-load bisphenol A and FA in drinking water sources has become one of the challenges faced by the drinking water treatment field. Therefore, researching and developing a new process for efficiently removing bisphenol A and FA from water is of great significance to the safety of drinking water.

Summary of the invention

The purpose of the present invention is to provide a system for efficiently removing bisphenol A and FA from surface water sources, which can quickly and effectively remove bisphenol A and FA from water and has a long service life.

Another object of the present invention is to provide a method for removing bisphenol A and FA from surface water sources using the above system, and to achieve effective removal of bisphenol A and FA by using ferrate and manganese modified molecular sieve filter materials.

The technical solution adopted by the present invention is a system for efficiently removing bisphenol A and FA from surface water sources, including a mixed reaction precipitation unit for removing tiny particles in surface water. The water outlet pipeline of the mixed reaction precipitation unit is connected to a reagent adapter adding unit, and the reagent adapter adding unit is used to add reagents to the water treated by the mixed reaction precipitation unit. The water with the added reagents flows into a filtering unit, and under the action of a filter material arranged in the filtering unit, bisphenol A and FA in the water are removed. The filtering unit is connected to a disinfection unit, and the disinfection unit is used to sterilize and disinfect the surface water.

The present invention is also characterized in that:

The filter unit is connected with a backwash unit and a filter material regeneration unit, which are used for backwashing and regenerating the filter material in the filter unit respectively.

The mixed reaction sedimentation unit includes a mixing tank, a reaction tank and a sedimentation tank which are connected in sequence. A coagulant is placed in the mixing tank. After the surface water enters the mixing tank and is fully mixed with the coagulant, it flows into the reaction tank for flocculation reaction to form larger floc particles. The floc particles and suspended matter in the water are then removed through the sedimentation action of the sedimentation tank. The outlet pipe of the sedimentation tank is connected to the filtration unit.

The reaction tank is in the form of a grid, a bar, a partition or a folded plate; the sedimentation tank is in the form of a horizontal flow, an inclined tube, an inclined plate, a combination of horizontal flow and inclined tube, or a combination of horizontal flow and inclined plate.

The reagent adaptor dosing unit includes a drug storage device a, the drug storage device a is connected to a metering dosing device a, the metering dosing device a is connected to the water outlet pipe of the sedimentation tank through a drug dosing pipe, and after the two are connected, they are connected to the water inlet pipe of the filtration unit through a pipeline, and a tubular static mixer is arranged on the pipeline;

Ferrate is placed in the drug storage device a, and the drug adaptor dosing unit is used to add ferrate to the outlet pipe of the mixing reaction precipitation unit;

The molar ratio of ferrate/bisphenol A used is 0.03-0.05; the mass ratio of ferrate/FA is 0.4-0.7.

The filtration unit comprises a filter tank, in which filter media is filled. The filter media adopts manganese modified molecular sieve filter media, and the filter layer thickness is 1.1m-1.5m.

The disinfection unit comprises a medicine storage device b, which is connected to a metering dosing device b, which is connected to a water outlet pipe of the filter unit, and a disinfectant is placed in the medicine storage device b.

The backwash unit includes a water suction well, which is connected to a backwash water pump, which is connected to the filter tank through a backwash water pipeline; the backwash unit also includes an air pressurizing device, which is connected to the filter tank through an air pipeline; the air pressurizing device is an air compressor or a blower.

The filter material regeneration unit comprises a drug storage device c, which is connected to the filter tank via a metering dosing device c, and an oxidant or a demolding agent is placed in the drug storage device c.

Another technical solution adopted by the present invention is a method for efficiently removing bisphenol A and FA from surface water sources, using the above system, and specifically implementing the following steps:

The surface water is fully mixed with the coagulant through a mixed reaction sedimentation unit, flocculated and precipitated to remove tiny particles in the surface water. It is then mixed with a ferrate solution and flows into a filtration unit. Under the action of the manganese-modified molecular sieve in the filtration unit, bisphenol A and FA in the surface water are removed. The water then enters the disinfection unit for sterilization and disinfection to obtain drinking water of qualified quality.

Another technical solution of the present invention is also characterized in that:

The molar ratio of ferrate/bisphenol A used is 0.03-0.05; the mass ratio of ferrate/FA is 0.4-0.7; the filter layer thickness of the manganese-modified molecular sieve filter material is 1.1m-1.5m, the filtration rate during filtration is 8m/h-11m/h, and the filtration cycle is 2d-3d.

The beneficial effects of the present invention are:

(1) The method of the present invention reasonably and effectively integrates multiple technologies such as mixed reaction precipitation, ferrate reagent adaptive addition, interception filtration, chemical contact catalytic oxidation, etc. to synergistically remove bisphenol A and fulvic acid (FA) in water sources, and can achieve better treatment effects;

(2) The method of the present invention has the technical advantages of good removal effect (bisphenol A removal of more than 95%, fulvic acid removal of about 57%), fast processing speed (effective removal at a filtration rate of 8 to 11 m/h), little impact by environmental factors, no side effects, simple operation and management, etc., and has the economic advantages of small engineering investment and low operating cost;

(3) The system of the present invention is not only suitable for the design of new surface water plants, but also easy to realize the upgrading and transformation of existing surface water plants. For the upgrading and transformation of existing surface water plants, it is only necessary to add a ferrate agent adaptation dosing system and replace the filter material of the filter tank with a manganese-modified molecular sieve, which can effectively improve the removal efficiency of bisphenol A and FA in water and ensure the water quality of the effluent.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic diagram of the structure of the system of the present invention;

FIG2 is a graph showing the effect of different concentrations of potassium ferrate on the removal of fulvic acid in Example 1 of the present invention;

3 is a graph showing the effect of different concentrations of potassium ferrate on the removal of bisphenol A in Example 2 of the present invention;

FIG4a is a graph showing the effect of different concentrations of potassium ferrate on the removal of fulvic acid when bisphenol A and fulvic acid are removed simultaneously in Example 3 of the present invention; FIG4b is a graph showing the effect of different concentrations of potassium ferrate on the removal of bisphenol A when bisphenol A and fulvic acid are removed simultaneously in Example 3 of the present invention;

Figure 5a is a diagram showing the removal effect of fulvic acid in the long-term operation experiment of Example 4 of the present invention; Figure 5b is a diagram showing the removal effect of bisphenol A in the long-term operation experiment of Example 4 of the present invention.

In the figure, 1. surface water;

2. Mixing reaction sedimentation unit, 21. Mixing tank, 22. Reaction tank, 23. Sedimentation tank;

3. Medicament adaptor dosing unit, 31. Drug storage device a, 32. Metering dosing device a, 33. Dosing pipe, 34. Tubular static mixer, 35. Pipeline;

4. filtration unit, 41. filter tank, 42. filter material;

5. disinfection unit, 51. metering and dosing device b, 52. drug storage device b;

6. Backwash unit, 61. Backwash water pump, 62. Water suction well, 63. Backwash water pipeline, 64. Air pressurizing device, 65. Backwash air inlet pipeline;

7. Filter material regeneration unit, 71. Metering and dosing device c, 72. Drug storage device c.

Detailed ways

The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

The system for efficiently removing bisphenol A and fulvic acid (FA) from surface water sources of the present invention has a structure as shown in FIG1 , and includes a mixing reaction precipitation unit 2 for mixing, reacting, and precipitating surface water 1; the outlet pipe of the mixing reaction precipitation unit 2 is connected to the reagent adaption adding unit 3, and the reagent adaption adding unit 3 is used to add ferrate adaption reagent to the surface water, and the surface water treated by the mixing reaction precipitation unit 2 and the ferrate reagent added by the reagent adaption adding unit 3 are mixed by a tubular static mixer 34 and flow into the filtering unit 4, and the filtering unit 4 is used to absorb bisphenol A and FA in the water, and at the same time intercept the suspended matter remaining in the water, and the filtering unit 4 is connected to the disinfection unit 5, which is used to kill the pathogenic microorganisms in the surface water treated by the filtering unit 4, and finally produce qualified drinking water. In addition, the filtering unit 4 is also connected to a backwashing unit 6 and a filter material regeneration unit 7, which are used to backwash and regenerate the filter material in the filtering unit 4.

The mixing reaction precipitation unit 2 comprises a mixing tank 21, a reaction tank 22 and a sedimentation tank 23 connected in sequence. The mixing tank 21 is connected to the surface water 1, wherein a coagulant is placed. The coagulant can be polyaluminium chloride (PAC) or polyferric chloride (PFC). The mixing tank 21 adopts mechanical mixing or hydraulic mixing. In order to achieve a better mixing effect, and considering the sedimentation rate of suspended matter, the uniformity of the reaction of potassium ferrate with bisphenol A and FA, etc., the stirring speed during mixing is set to 10-60r/min; the reaction tank 22 is in the form of a grid, a bar, a partition or a folded plate; the sedimentation tank 23 is in the form of a horizontal flow, an inclined tube or an inclined plate, or a combination of horizontal flow and inclined tube, or a combination of horizontal flow and inclined plate. After the surface water 1 enters the mixing tank 21, it is fully mixed with the coagulant, and then flows into the reaction tank 22 for a full flocculation reaction to form larger floc particles, and then the floc particles and suspended matter in the water are removed by the sedimentation action of the sedimentation tank 23, and then mixed with the agent in the agent adaptation dosing unit 3 and flows into the filtration unit 4.

The reagent adapting and adding unit 3 includes a drug storage device a31, the drug storage device a31 is connected to a metering and adding device a32, and the metering and adding device a32 is connected to the outlet pipe of the sedimentation tank 23 through a drug adding pipe 33. After the two are connected, they are connected to the water inlet pipe of the filter unit 4 through a pipe 35, and a tubular static mixer 34 is arranged on the pipe 35. The drug added by the drug adapting and adding unit 3 is ferrate, preferably potassium ferrate or sodium ferrate, and contains 0.5% to 2% of calcium ferrate or manganese ferrate by mass. The drug is stored in the drug storage device a31 in the form of a solution. When used, the metering and adding device a32 adds the drug stored in the drug storage device a31 to the water after coagulation and precipitation by the mixing reaction precipitation unit 2 through the drug adding pipe 33, and then mixes it evenly through the tubular static mixer 34, and then enters the filter unit 4. The dosage of ferrate can be determined according to the amount of raw water to be treated and the concentrations of bisphenol A and FA in the raw water.

In other existing processes for removing bisphenol A, as disclosed in the literature (Zhao Xiaona. Effect of divalent manganese on the oxidation and degradation of bisphenol A by potassium ferrate and its mechanism of action [D]. Harbin Institute of Technology, 2022.) and the literature (Dong Jinhua. Research on the oxidation and degradation of bisphenol A in water by potassium ferrate [D]. Hunan University, 2010.), when the molar ratio of K ₂ FeO ₄ /bisphenol A is 0.2, the degradation rate of bisphenol A reaches 41.2%; when the molar ratio of K ₂ FeO ₄ /bisphenol A increases to 2, the degradation rate of bisphenol A significantly increases to 89.9%. However, in the process of the present invention, when the molar ratio is only 0.03, the degradation rate can reach 95.3%; when the molar ratio of K ₂ FeO ₄ /bisphenol A reaches 0.05, the bisphenol A in the raw water is completely degraded. Specifically, in the process of the present invention, the molar ratio of ferrate/bisphenol A is set at 0.03-0.05.

In other existing FA removal processes, such as those disclosed in the literature (Cheng Yanhui, Yuan Xiangjuan, Deng Huiyuan, etc. Study on UV-potassium ferrate combined oxidation treatment of bisphenol A in water [J]. Applied Chemical Industry, 2023, 52(06): 1682-1688.) and the literature (Qu Jiuhui, Lin Su, Tian Baozhen, etc. Study on ferrate oxidation flocculation removal of humus in water [J]. Journal of Environmental Science, 1999(05): 510-514), when the mass ratio of K ₂ FeO ₄ /FA is 12, ferrate oxidation can remove more than 50% of FA in water; when the value of K ₂ FeO ₄ /FA is greater than 15, the residual amount of FA in water is basically no longer significantly reduced by the increase in the amount of potassium ferrate added. However, under the condition of the same removal rate, the required mass ratio of K ₂ FeO ₄ /FA in the degradation method of the present invention is only between 0.4 and 0.7.

A filter tank 41 is provided in the filter unit 4, and a filter material 42 is filled in the filter tank 41. The filter material 42 adopts a manganese-modified molecular sieve filter material with adsorption and catalytic oxidation capabilities. The filter material is prepared by the method disclosed in the invention patent with publication number CN112939007B. The filter layer thickness is 1.1m to 1.5m, and the filtration rate during filtration is preferably 8m/h to 11m/h, and the filtration cycle is preferably 2d to 3d. In terms of this process, when the filtration rate is lower than 8m/h, the water treatment volume of the entire filtration unit will be reduced, and the initial construction cost will be increased; when the filtration rate is too high, a stable removal effect cannot be achieved, and the filter layer will be more easily blocked, shortening the filtration cycle and increasing the later operation cost. The ferrate added by the reagent adapter dosing unit 3 enters the filter tank 41 and is adsorbed onto the surface of the filter material 42, further enhancing the catalytic oxidation ability of the active oxide film on the surface of the filter material 42. Under the joint action of the filter material 42 and its surface active oxide film, chemical adsorption and contact catalytic oxidation of bisphenol A and FA in the water are achieved, and at the same time, residual suspended matter in the water is intercepted, reducing the turbidity and color of the water.

The disinfection unit 5 includes a medicine storage device b52, which is connected to a metering dosing device b51, and the metering dosing device b51 is connected to the outlet pipe of the filter unit 4. A disinfectant is placed in the medicine storage device b52, and the disinfectant is added to the outlet pipe of the filter unit 4 through the metering dosing device b51 to sterilize and disinfect the water after being treated by the filter unit 4, kill the pathogenic microorganisms therein, remove the organic matter and color in the water, and ensure the quality of the water finally produced. The disinfectant can be chlorine, sodium hypochlorite, chlorine dioxide, etc., and the dosage is calculated and determined according to the water output, the type of medicine and the residual chlorine in the water.

The backwash unit 6 includes a water suction well 62, which is connected to a backwash water pump 61, and the backwash water pump 61 is connected to the filter tank 41 through a backwash water pipeline 63; the backwash unit 6 also includes an air pressurizing device 64, which is connected to the filter tank 41 through an air pipeline 65, and the air pressurizing device 64 is an air compressor or a blower. The backwash water pump 61 absorbs water from the water suction well 62 through a pipeline to provide backwash water to the filter tank 41, and the air pressurizing device 64 provides backwash air to the filter tank 41. The water and air flushing strengths can be reasonably selected according to the "Outdoor Water Supply Design Code" ( _GB50013-2006 ) and the thickness of the filter layer, wherein the preferred air flushing strength is 14L/( ^m2.s ), the water flushing strength is 6L/( ^m2.s ) when the air and water are flushed together, ^{and the water flushing strength is 15L/(m2.s} ₎ when the water is flushed alone _. When the present invention uses ferrate-enhanced manganese-modified molecular sieve to remove bisphenol A and FA in water, complex long-chain organic matter will be formed on the surface of the manganese-modified molecular sieve filter material. Therefore, the filter material is subjected to combined air-water backwashing and the intensity of the air flushing is increased to achieve a better backwashing effect.

The filter material regeneration unit 7 includes a medicine storage device c72, which is connected to the filter tank 41 through a metering dosing device c71, and an oxidant or a demolding agent is placed in the medicine storage device c72. The filter material regeneration unit 7 is used to regenerate the manganese modified molecular sieve filter material, which uses the strong oxidizing effect of the oxidant or the strong acidity of the demolding agent to peel off the aged filter membrane to restore its original activity. The oxidant can be hydrogen peroxide, chlorine dioxide or ozone with strong oxidizing properties, and the demolding agent can be HCl, which has a dissolving effect on the metal oxide on the surface of the oxide film, can destroy the oxide lattice structure, and realize the stripping of the oxide film material. The dosage is determined according to the amount of filter material and the type of oxidant or demolding agent, and the regeneration cycle can be controlled at 3 to 5 years.

The method of the present invention utilizes the system disclosed in the present invention, uses ferrate and manganese-modified molecular sieve to work together to adsorb bisphenol A and FA in water, and can achieve good absorption effect with a small amount of ferrate, mainly because:

(1) Ferrate has strong oxidizing properties. When it comes into contact with manganese-modified molecular sieve filter media, the two will react to form active manganese oxide substances (MnO _x ) on the filter media surface. This active substance also has certain oxidizing properties. Therefore, ferrate-modified manganese molecular sieve has stronger oxidizing properties and can provide more oxidants per unit mass, thus achieving more significant effects in removing bisphenol A and fulvic acid, which can reduce the amount of ferrate used;

(2) Ferrate-modified manganese molecular sieves may have more specific active sites, thus having a faster reaction rate and being more efficient when reacting with bisphenol A and fulvic acid;

(3) Experimental verification shows that the ferrate-modified manganese molecular sieve used in the method of the present invention can reduce or avoid the generation of some undesirable by-products and improve the selectivity of the removal effect. This helps to reduce the complexity of subsequent processing steps and reduce the overall processing cost;

(4) The modified molecular sieve has better durability and regeneration performance. Ferrate can oxidize ^Mn2+ in water into active manganese oxide, which adheres to the surface of the molecular sieve. By utilizing this self-catalytic oxidation property, the manganese-modified molecular sieve filter material can be used multiple times without losing its activity (as disclosed in Example 4 below, when the removal effect of bisphenol A is not good during long-term operation, adding 1 mg/L of Mn2 ⁺ to the influent water can restore the activity of the manganese-modified molecular sieve, so that bisphenol A can be completely removed). Even when the backwash intensity is very low, a good removal effect can be achieved.

Therefore, compared with other existing methods, the method of the present invention is excellent in environmental friendliness and almost no by-products are generated. In practical applications, the method has shown excellent results, with less ferrate dosage, lower addition cost and excellent removal effect. This provides a feasible and sustainable solution for the treatment of bisphenol A and FA.

Example 1

The system of the present invention is used to remove FA in water, the initial concentration of FA is 7 mg/L, the ferrate used is potassium ferrate, and the concentrations are 2 mg/L, 3 mg/L, 4 mg/L and 5 mg/L respectively, wherein the water inflow of FA solution and potassium ferrate solution is 50 L, and the formula: m (mass) = A (concentration) × V (volume) is used to obtain the mass of FA and potassium ferrate in the inflow water, and then the mass ratio of potassium ferrate to FA can be obtained to be between 0.4 and 0.7. The water containing FA is passed into the mixing reaction precipitation unit 2, after mixing, reaction and precipitation treatment, it is mixed with potassium ferrate agent, and then enters the filtering unit 4, under the joint action of manganese modified molecular sieve filter material and potassium ferrate, FA is removed, and finally sterilized by the disinfection unit 5 to obtain water after FA is removed.

The removal effect of potassium ferrate at different concentrations on fulvic acid (FA) at different filter layer depths is shown in Figure 2. It can be seen that when the filter layer depth is 10 cm, the potassium ferrate at the above concentrations can remove most of the FA, and as the potassium ferrate dosage increases from 2 mg/L to 3 mg/L, the removal of fulvic acid also gradually increases, but the removal effect of 4 mg/L and 5 mg/L potassium ferrate is not much different from that of 3 mg/L. Therefore, for the case of FA of 7 mg/L, the optimal dosage of potassium ferrate is 3 mg/L. In addition, the removal of FA at a filter layer depth of 20 to 120 cm shows a slow increasing trend, and it can be seen that the final concentration of FA obtained at different filter layer depths is slightly different. In summary, the system of the present invention has a better effect in removing fulvic acid, and can efficiently and quickly remove FA in water at a smaller filter layer thickness.

Example 2

The system of the present invention is used to remove bisphenol A in water, the initial concentration of bisphenol A is 0.7 mg/L, the ferrate used is potassium ferrate, the concentrations are 0 mg/L, 0.01 mg/L, 0.02 mg/L and 0.03 mg/L respectively, the water inflow of bisphenol A solution and potassium ferrate solution are both 50 L, and the molar ratio of potassium ferrate to bisphenol A is between 0.03 and 0.05. The remaining steps are the same as in Example 1.

The removal effect of potassium ferrate at different concentrations on bisphenol A at different filter layer depths is shown in Figure 3. It can be seen that when potassium ferrate is not added (i.e., when the concentration is 0 mg/L), the removal rate of bisphenol A in the filtration system is less than 50%, and after adding potassium ferrate, the removal effect of bisphenol A is greatly improved, and the removal rate can reach more than 80%. And when the concentration of potassium ferrate is 0.02 mg/L, bisphenol A in water can be completely removed. However, as the concentration of potassium ferrate continues to increase (up to 0.03 mg/L), the removal rate of bisphenol A at different filter layer depths does not increase significantly, and the removal effect is not much different from that when the concentration of potassium ferrate is 0.02 mg/L. Therefore, considering economic factors and other factors, the optimal dosage of potassium ferrate is 0.02 mg/L for the case of bisphenol A at 0.7 mg/L. In addition, the depth of the filter layer has a greater impact on the removal effect of bisphenol A. The thicker the filter layer, the better the removal effect.

Example 3

In this embodiment, bisphenol A and FA are simultaneously removed from water, wherein the initial concentration of fulvic acid is 7 mg/L, the initial concentration of bisphenol A is 0.7 mg/L, and the ferrate used is potassium ferrate, with concentrations of 3.02 mg/L, 3.04 mg/L, 3.06 mg/L, 3.07 mg/L and 3.08 mg/L, respectively. The remaining steps are the same as in Example 1.

During simultaneous removal, the removal effects of different concentrations of potassium ferrate on bisphenol A and FA are shown in Figures 4a and 4b, respectively. It can be seen that as the concentration of potassium ferrate increases from 3.02 mg/L to 3.08 mg/L, the removal amount of fulvic acid has almost no change, the removal effect is not affected, and the removal efficiency can still be maintained at more than 50%. During the simultaneous removal process, the removal effect of bisphenol A changes more significantly. When the concentration of potassium ferrate is 3.02 mg/L, bisphenol A in the water cannot be completely removed. This is mainly because fulvic acid has a certain inhibitory effect on the removal of bisphenol A in water, affecting the removal effect of bisphenol A. However, as the concentration of potassium ferrate continues to increase (up to 3.08 mg/L), the final effluent bisphenol A concentration is zero, which is the same as the removal effect when the concentration of potassium ferrate is 3.06 mg/L. Therefore, considering various factors comprehensively, the optimal addition concentration of potassium ferrate during simultaneous removal is 3.06 mg/L.

Example 4

On the basis of Example 3, a long-term operation experiment of simultaneous removal of bisphenol A and FA was carried out. The concentration of fulvic acid in the influent was controlled at about 7 mg/L, the concentration of bisphenol A was controlled at about 0.7 mg/L, and the concentration of potassium ferrate was controlled at about 3.06 mg/L. The experimental results are shown in Figures 5a and 5b. It can be seen that with the increase in the number of operating days, the system's removal effect on FA remained stable for 60 days, with almost no change, and the removal rate was always able to remain at about 50%. As for bisphenol A, during the continuous operation process of up to 60 days, bisphenol A in the influent at the beginning of the operation can be stably and completely removed, but from the 23rd day, the residual concentration of bisphenol A began to gradually increase, mainly because the adsorption sites of the iron-manganese oxide film were gradually occupied, resulting in a gradual deterioration in the removal effect of bisphenol A. Starting from the 30th day, after adding 1 mg/L of Mn ²⁺ to the influent, the removal effect of bisphenol A gradually recovered, and finally the process system was restored to the sustainable and stable removal of bisphenol A in water. Compared with the prior art, the removal effect of the method of the present invention is already at a higher level. The ferrate used in the present invention is an efficient and environmentally friendly strong oxidant, which can quickly oxidize organic matter in water into harmless products, and has strong applicability for the removal of micro-pollutants in water. In addition, the manganese-modified molecular sieve filter material used in the present invention has a large specific surface area and pore structure, can effectively adsorb organic matter in water, improve the removal efficiency of organic matter, and produce less by-products, which helps to reduce the impact of the treatment process on the environment.

Claims (6)

1. The system for efficiently removing bisphenol A and FA in surface water sources is characterized by comprising a mixed reaction precipitation unit (2) for removing tiny particles in the surface water, wherein an outlet pipeline of the mixed reaction precipitation unit (2) is connected with a medicament adaptive dosing unit (3), the medicament adaptive dosing unit (3) is used for dosing medicament into the water treated by the mixed reaction precipitation unit (2), the water with the medicament is flowed into a filtering unit (4), bisphenol A and fulvic acid in the water are removed under the action of a filter material (42) arranged in the filtering unit (4), the filtering unit (4) is connected with a disinfection unit (5), and the disinfection unit (5) is used for carrying out disinfection treatment on the surface water;

The mixed reaction sedimentation unit (2) comprises a mixing tank (21), a reaction tank (22) and a sedimentation tank (23) which are sequentially connected, wherein a coagulant is placed in the mixing tank (21), surface water enters the mixing tank (21) to be fully mixed with the coagulant, and then flows into the reaction tank (22) to carry out flocculation reaction to form larger flocculent particles, the flocculent particles and suspended matters in the water are removed through the sedimentation effect of the sedimentation tank (23), and a water outlet pipe of the sedimentation tank (23) is connected with the filtering unit (4);

The reaction tank (22) is in the form of a grid, a grid strip, a baffle plate or a folded plate; the sedimentation tank (23) is in a advection, inclined pipe, inclined plate, advection and inclined pipe combination or advection and inclined plate combination form;

The medicament adaptive dosing unit (3) comprises a medicament storage device a (31), the medicament storage device a (31) is connected with a metering dosing device a (32), the metering dosing device a (32) is connected with a water outlet pipe of the sedimentation tank (23) through a dosing pipe (33), and after the metering dosing device a and the water outlet pipe are connected, the metering dosing device a is connected with a water inlet pipe of the filtering unit (4) through a pipeline (35), and a tubular static mixer (34) is arranged on the pipeline (35);

ferrate is placed in the drug storage device a (31), and the drug adaptation adding unit (3) is used for adding the ferrate into the water outlet pipeline of the mixed reaction precipitation unit (2);

The mol ratio of ferrate to bisphenol A is 0.03-0.05; the mass ratio of ferrate to FA is 0.4-0.7;

The filtering unit (4) comprises a filtering tank (41), a filtering material (42) is filled in the filtering tank (41), the filtering material (42) adopts a manganese modified molecular sieve filtering material, and the thickness of a filtering layer is 1.1-1.5 m;

the coagulant is polyaluminum chloride or polyferric chloride.

2. The system for efficiently removing bisphenol a and FA from a surface water source according to claim 1, wherein the filtering unit (4) is connected with a back flushing unit (6) and a filtering material regenerating unit (7) for back flushing and regenerating the filtering material (42) in the filtering unit (4), respectively.

3. The system for efficiently removing bisphenol a and FA from a surface water source according to claim 1, wherein the disinfection unit (5) comprises a medicine storage device b (52), the medicine storage device b (52) is connected with a metering and adding device b (51), the metering and adding device b (51) is connected with a water outlet pipeline of the filtering unit (4), and the disinfectant is placed in the medicine storage device b (52).

4. The system for efficiently removing bisphenol a and FA from a surface water source according to claim 2, wherein the back flush unit (6) comprises a water suction well (62), the water suction well (62) is connected with a back flush water pump (61), and the back flush water pump (61) is connected with the filter tank (41) through a back flush water pipe (63); the back flushing unit (6) further comprises an air pressurizing device (64), and the air pressurizing device (64) is connected with the filter tank (41) through a gas pipeline (65); the air pressurizing device (64) is an air compressor or a blower.

5. The system for efficiently removing bisphenol a and FA from a surface water source according to claim 2, wherein the filter material regeneration unit (7) comprises a medicine storage device c (72), the medicine storage device c (72) is connected with the filter tank (41) through a metering and adding device c (71), and an oxidizing agent or a mold release agent is placed in the medicine storage device c (72).

6. A method for efficiently removing bisphenol a and FA from a surface water source, characterized by using a system according to any one of claims 1-5, in particular according to the following steps:

The surface water is fully mixed with a coagulant through a mixed reaction precipitation unit (2), subjected to flocculation reaction and precipitation, tiny particles in the surface water are removed, then the surface water is mixed with ferrate solution and flows into a filtering unit (4), bisphenol A and FA in the surface water are removed under the action of a manganese modified molecular sieve in the filtering unit (4), and then the surface water enters a disinfection unit (5) for disinfection, so that qualified drinking water is obtained;

the mol ratio of ferrate to bisphenol A is 0.03-0.05; the mass ratio of ferrate to FA is 0.4-0.7; the thickness of the filtering layer of the manganese modified molecular sieve filtering material is 1.1-1.5 m, the filtering speed during filtering is 8-11 m/h, and the filtering period is 2-3 d;

In the bisphenol A and FA removal process, back flushing is carried out on the filter material, wherein the air flushing strength is 14L/(m ² _. s), the water flushing strength in the air-water combined flushing is 6L/(m ² _. s), and the water flushing strength in the single water flushing is 15L/(m ² _. s).