Method for removing typical new pollutants in water by adopting combination of superfine powdered activated carbon and ultrafiltration membrane

Abstract

The invention provides a method for removing typical new pollutants in water by adopting a combination of superfine powder activated carbon and an ultrafiltration membrane, which comprises the following steps: adding a to-be-treated water sample containing the typical new pollutants into an ultrafiltration process membrane pool, and continuously adding superfine powder activated carbon slurry into the to-be-treated water sample, carrying out adsorption treatment and stirring treatment to obtain a mixed solution, and filtering the mixed solution by utilizing an ultrafiltration process to obtain a treated water sample. According to the method, new pollutants in water are effectively adsorbed and removed by adopting superfine powdered activated carbon, and the removal effect of conventional pollutants is further improved while the superfine powdered activated carbon added into water is effectively separated by using an ultrafiltration process, so that additional influence caused by the superfine powdered activated carbon is avoided, the concentration of the new pollutants in the effluent is reduced, and the water quality is improved. And the effluent quality of waterworks, domestic sewage treatment plants, industrial wastewater treatment plants and reclaimed water plants can meet related requirements.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and in particular to a method for removing typical new pollutants from water using a combination of ultrafine powdered activated carbon and ultrafiltration membrane. Background Technology

[0002] Emerging contaminants refer to chemical substances emitted into the environment that possess toxic effects such as biotoxicity, environmental persistence, and bioaccumulation, posing significant risks to the ecological environment or human health, but which are not yet included in regulations or for which existing management measures are insufficient. In recent years, emerging contaminants have received increasing attention and research from academic and industrial communities both domestically and internationally. Furthermore, as understanding and research deepen, the scope of emerging contaminants continues to expand. Currently, the most concerning emerging contaminants include perfluorinated compounds, pharmaceuticals and personal care products (including antibiotics), endocrine disruptors, microplastics, novel pesticides, and novel disinfection byproducts.

[0003] Studies show that various new pollutants have been widely detected in wastewater, reclaimed water, surface water, groundwater, and drinking water globally, with concentrations typically in the ppt or ppb range, and even reaching ppm levels in industrial wastewater and contaminated soil. It is noteworthy that the vast majority of existing reclaimed water plants and water treatment plants were designed only to remove conventional pollutants and are ineffective in reducing new pollutants. This means that a significant portion of new pollutants generated during human production and daily life enters the aquatic environment directly with reclaimed water. These new pollutants then enter water sources via surface runoff, subsequently enter tap water at water treatment plants, and are ultimately ingested through drinking water exposure, threatening human health and safety.

[0004] Activated carbon adsorption technology is considered one of the most effective and feasible methods for removing new pollutants from water bodies due to its wide applicability, ease of use, and low cost. However, the activated carbon used in existing powdered activated carbon-ultrafiltration processes is powdered activated carbon with a particle size of 40-78 μm. The time required for powdered activated carbon to adsorb pollutants and reach adsorption saturation often takes several hours. In actual production, the powdered activated carbon-ultrafiltration process is limited by space and cost constraints, making it impossible to meet the long hydraulic retention time requirements. This results in the limited contact time during actual production, preventing the full utilization of its adsorption capacity and significantly limiting its adsorption effect on new pollutants. Therefore, upgrading the existing powdered activated carbon-ultrafiltration process to improve its adsorption and removal efficiency for new pollutants while ensuring effluent safety is of significant practical importance. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention provides a method for removing new pollutants from water using a combination of ultrafine powdered activated carbon and an ultrafiltration membrane. This method utilizes ultrafine powdered activated carbon to effectively adsorb and remove new pollutants from water, while the ultrafiltration process effectively separates the ultrafine powdered activated carbon added to the water, further improving the removal efficiency of conventional pollutants. It avoids the additional impacts of ultrafine powdered activated carbon, reduces the concentration of new pollutants in the effluent, and ensures that the effluent quality of waterworks, sewage treatment plants, industrial wastewater treatment plants, and reclaimed water plants meets relevant requirements.

[0006] This invention provides a method for removing typical new pollutants from water using a combination of ultrafine powdered activated carbon slurry and an ultrafiltration membrane. The method combines ultrafine powdered activated carbon and an ultrafiltration membrane, utilizing the rapid adsorption and removal of typical new pollutants by the ultrafine powdered activated carbon, followed by filtration and retention by the ultrafiltration membrane. This effectively removes new pollutants from the water sample while avoiding the additional pollution problems associated with adding ultrafine powdered activated carbon. The activated carbon in the activated carbon slurry is ultrafine powdered activated carbon with a median particle size of 1 μm-5 μm and a specific surface area of ​​900 m². 2 / g-1500 m 2 The average pore size is 1.5 nm-2.0 nm, and the total pore volume is 0.4 mL / g-0.8 mL / g. The ultrafiltration membrane has a pore size of 50-100 nm, the hydraulic retention time of the ultrafiltration membrane cell is 5-30 min, and the membrane flux is 20-116 L / m³. 2 The filtration cycle is 30-60 minutes, the backwashing time is 30 seconds, and the backwashing flux is 20-146 L / m³. 2 This technology can solve the problems that conventional processes in existing waterworks, reclaimed water plants, and sewage treatment plants are unable to remove new pollutants, that traditional powdered activated carbon-ultrafiltration processes have limited adsorption effects on new pollutants, that ozone-activated carbon processes have large footprints and high construction costs, and that ultrafine powdered activated carbon poses a risk of filter penetration. It provides a technical solution for the treatment of new pollutants in drinking water, domestic sewage, and industrial wastewater, and has good prospects for practical application.

[0007] In one aspect, the present invention provides a method for removing typical new pollutants from water using a combination of ultrafine powdered activated carbon and an ultrafiltration membrane. According to an embodiment of the present invention, the method includes: A water sample containing typical new pollutants was added to the ultrafiltration membrane tank, and activated carbon slurry was continuously added to the water sample for adsorption and stirring to obtain a mixed solution. The mixture was filtered using ultrafiltration (the filtration process retains the ultrafine activated carbon that has adsorbed new pollutants) to obtain a treated water sample. The activated carbon used in the activated carbon slurry is ultrafine powder activated carbon, with a median particle size of 1 μm-5 μm and a specific surface area of ​​900 m². 2 / g-1500 m 2 / g, with an average pore size of 1.5 nm-2.0 nm and a total pore volume of 0.4 mL / g-0.8 mL / g; The filter membrane in the ultrafiltration process membrane pool is an ultrafiltration membrane with a pore size of 50-100 nm.

[0008] According to embodiments of the present invention, the above method may further include at least one of the following additional technical features: According to an embodiment of the present invention, the ultrafiltration membrane is a ceramic ultrafiltration membrane.

[0009] According to embodiments of the present invention, the typical novel contaminants include perfluorinated compounds and / or pharmaceutical personal care products.

[0010] According to embodiments of the present invention, the perfluorinated compound includes at least one selected from perfluorobutyric acid, perfluorovalerate, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluorobutylsulfonic acid, perfluorohexylsulfonic acid, perfluorooctylsulfonic acid, and perfluorodecylsulfonic acid.

[0011] According to an embodiment of the present invention, the pharmaceutical personal care product includes at least one selected from ranitidine and nizatidine.

[0012] According to an embodiment of the present invention, the content of ultrafine powder activated carbon in the activated carbon slurry is 10wt%-30wt%.

[0013] According to an embodiment of the present invention, the adsorption time of the ultrafine powder activated carbon is 5-30 min.

[0014] According to an embodiment of the present invention, the stirring intensity of the stirring process is 500-800 / s as measured by a hydraulic gradient meter.

[0015] According to an embodiment of the present invention, the content of the ultrafine powdered activated carbon in the mixture is 5 mg / L-40 mg / L.

[0016] According to an embodiment of the present invention, the hydraulic retention time of the ultrafiltration process is 5-30 min.

[0017] According to an embodiment of the present invention, the membrane flux of the ultrafiltration process is 20-116 L / m³. 2 ·h.

[0018] According to an embodiment of the present invention, the filtration cycle of the ultrafiltration membrane tank is 30-60 min, the backwashing interval is 30 s, and the backwashing flux is 20-146 L / m³. 2 ·h.

[0019] In another aspect, the present invention also proposes the application of ultrafine powder activated carbon in the removal of pollutants from water. According to an embodiment of the present invention, the pollutant is a pharmaceutical or personal care product, and the ultrafine powder activated carbon has a median particle size of 1 μm-5 μm and a specific surface area of ​​900 m². 2 / g-1500 m 2 / g, with an average pore size of 1.5 nm-2.0 nm and a total pore volume of 0.4 mL / g-0.8 mL / g.

[0020] According to embodiments of the present invention, the above application may further include at least one of the following additional technical features: According to an embodiment of the present invention, the pharmaceutical personal care product includes at least one selected from ranitidine and nizatidine.

[0021] In another aspect of the invention, a device is proposed for removing typical new pollutants from water using a combination of ultrafine powdered activated carbon and an ultrafiltration membrane. According to an embodiment of the invention, the device comprises: Raw water tank (1) is used to store water samples to be treated; Water inlet pump (2), which is connected to the raw water tank (1); Membrane tank (4), the membrane tank (4) and the inlet pump (2), when the inlet pump (2) is turned on, the water sample to be treated in the raw water tank (1) enters the membrane tank (4); A stirrer (3) is connected to the membrane tank (4) and is used to control the mixing of water sample and activated carbon slurry in the membrane tank (4) for stirring treatment. Ultrafiltration membrane (5), the ultrafiltration membrane (5) is located in the membrane tank (4) and is used to treat the water sample and activated carbon slurry in the membrane tank (4) by ultrafiltration process; Pressure gauge (9), which is connected to the ultrafiltration membrane (5); A negative pressure water pump (10) is connected to the pressure gauge (9); The activated carbon used in the activated carbon slurry is ultrafine powder activated carbon, with a median particle size of 1 μm-5 μm and a specific surface area of ​​900 m². 2 / g-1500 m 2 / g, with an average pore size of 1.5 nm-2.0 nm and a total pore volume of 0.4 mL / g-0.8 mL / g.

[0022] According to embodiments of the present invention, the above-described apparatus may further include at least one of the following additional technical features: According to an embodiment of the present invention, the apparatus further comprises: A backwash pump (8) is connected to the ultrafiltration membrane (5); Backwash water tank (7), the backwash water tank (7) is connected to the backwash water tank (7); According to an embodiment of the present invention, the apparatus further comprises: Pressure monitoring device (11), which is connected to the pressure gauge (9).

[0023] According to an embodiment of the present invention, the contaminants in the water sample to be treated include perfluorinated compounds and / or pharmaceuticals and personal care products.

[0024] According to embodiments of the present invention, the perfluorinated compound includes at least one selected from perfluorobutyric acid, perfluorovalerate, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluorobutylsulfonic acid, perfluorohexylsulfonic acid, perfluorooctylsulfonic acid, and perfluorodecylsulfonic acid.

[0025] According to an embodiment of the present invention, the pharmaceutical personal care product includes at least one selected from ranitidine and nizatidine.

[0026] According to an embodiment of the present invention, the pore size of the ultrafiltration membrane is 50-100 nm.

[0027] According to an embodiment of the present invention, the content of the ultrafine powdered activated carbon in the mixture is 5 mg / L-40 mg / L.

[0028] According to an embodiment of the present invention, the hydraulic retention time of the ultrafiltration process is 5-30 min.

[0029] According to an embodiment of the present invention, the membrane flux of the ultrafiltration process is 20-116 L / m³. 2 ·h.

[0030] According to an embodiment of the present invention, the filtration cycle of the ultrafiltration membrane tank is 30-60 min, the backwashing interval is 30 s, and the backwashing flux is 20-146 L / m³. 2 ·h.

[0031] In another aspect, the present invention also proposes a water treatment method for removing typical new pollutants using a combination of ultrafine powdered activated carbon and an ultrafiltration membrane. According to an embodiment of the present invention, the method includes the following steps: The water sample containing typical new pollutants was added to the ultrafiltration membrane tank, and ultrafine activated carbon slurry was continuously added to the water sample for stirring to obtain a mixed solution. While stirring, ultrafiltration is used to remove the ultrafine powdered activated carbon that has adsorbed new pollutants from the mixture, thereby achieving the removal of typical new pollutants from the water sample to be treated. The ultrafine powder activated carbon has a median particle size of 1 μm-5 μm and a specific surface area of ​​900 m². 2 / g-1500m 2 / g, with an average pore size of 1.5 nm-2.0 nm and a total pore volume of 0.4 mL / g-0.8 mL / g.

[0032] According to embodiments of the present invention, the above method may further include at least one of the following additional technical features: According to an embodiment of the present invention, the content of ultrafine powder activated carbon in the activated carbon slurry is 10wt%-20wt%.

[0033] According to an embodiment of the present invention, the content of the ultrafine powder activated carbon in the mixture is 5 mg / L-40 mg / L.

[0034] According to an embodiment of the present invention, the pore size of the ultrafiltration membrane is 50-100 nm.

[0035] According to an embodiment of the present invention, the hydraulic retention time of the ultrafiltration process is 5-30 min; According to an embodiment of the present invention, the adsorption time of the ultrafine powder activated carbon is 5-30 min.

[0036] According to an embodiment of the present invention, the membrane flux of the ultrafiltration process is 20-116 L / m³. 2 ·h.

[0037] According to an embodiment of the present invention, the filtration cycle of the membrane tank is 30-60 min, the backwash interval is 30 s, and the backwash flux is 20-146 L / m³. 2 ·h,.

[0038] According to embodiments of the present invention, the typical novel contaminants include at least one of perfluorinated compounds, pharmaceuticals, and personal care products; According to embodiments of the present invention, the perfluorinated compound includes at least one selected from perfluorobutyric acid, perfluorovaleric acid, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluorobutylsulfonic acid, perfluorohexylsulfonic acid, perfluorooctylsulfonic acid, and perfluorodecylsulfonic acid. According to embodiments of the present invention, the pharmaceutical and personal care products include at least one of ranitidine and nizatidine.

[0039] According to an embodiment of the present invention, the stirring intensity of the stirring process is 500-800 / s as measured by a hydraulic gradient meter.

[0040] According to an embodiment of the present invention, after the mixture is filtered, the turbidity of the filtrate is <0.3 NTU.

[0041] The method provided by this invention replaces the 40-78 μm particle size powdered activated carbon used in the original powdered activated carbon-ultrafiltration process with pre-processed ultrafine powdered activated carbon with a median particle size of less than 5 μm, achieving highly efficient adsorption and removal of new pollutants. Simultaneously, the ultrafiltration process effectively ensures the efficient separation of the ultrafine powdered activated carbon after adsorbing new pollutants from the water, avoiding the impact on the original water plant process after replacing powdered activated carbon with ultrafine powdered activated carbon. Furthermore, the ultrafine powdered activated carbon used in this method is transported in the form of pre-processed carbon slurry and added to the water plant, avoiding the potential dust explosion hazards during production, transportation, and use, and reducing environmental pollution problems for workers. In addition, the ultrafiltration process used in this invention can form a denser filter cake layer than powdered carbon during the separation of ultrafine powdered activated carbon, further enhancing the retention capacity of the membrane filtration process, resulting in a stronger filtration effect for both conventional and new pollutants, fully ensuring water quality safety.

[0042] According to embodiments of the present invention, the present invention has at least one of the following beneficial effects compared to the prior art: (1) The method provided by the present invention uses ultrafine powder activated carbon with smaller particle size to replace the powder activated carbon in the original powdered carbon-ultrafiltration process, so that the upgraded process has a better adsorption and removal effect on new pollutants in a shorter contact time. By using specific process parameters, a better overall interaction is achieved. While removing new pollutants, it can efficiently separate ultrafine powder activated carbon in water, avoid the secondary pollution problem caused by the use of ultrafine powder activated carbon, and reduce the interference with the existing processes of tap water plants, domestic sewage treatment plants, industrial wastewater treatment plants, and reclaimed water plants. In addition, the ultrafiltration process in the present invention can also form a denser ultrafine powder activated carbon filter cake layer during operation, which can further remove conventional pollutants and some new pollutants, and improve water treatment efficiency. (2) The ultrafine powder activated carbon used in this invention is transported in the form of pre-processed carbon slurry and added to the water plant, which avoids the dust explosion hazard that may be caused by the ultrafine powder activated carbon during production, transportation and use, and reduces the environmental pollution problem of workers' operation. (3) The method provided by the present invention is simple and convenient, and its use, frequency and scale are flexible and diverse. It can also be used as a substitute for some of the original process links of water plants and can be used for a long time. It has a limited impact on water treatment costs. It solves the problem of new pollutant pollution faced by tap water plants, domestic sewage treatment plants, industrial wastewater treatment plants and reclaimed water plants without generating additional impacts. It has good economic benefits and practical application prospects. Attached Figure Description

[0043] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 The diagram shows the adsorption effect of ultrafine powder activated carbon used in Example 1 of the present invention on perfluoroalkyl acids; Figure 2 The diagram shows the adsorption effect of ultrafine powder activated carbon used in Example 1 of the present invention on perfluoroalkyl sulfonic acid; Figure 3 The diagram shows the adsorption effect of ultrafine powder activated carbon used in Example 2 of the present invention on ranitidine and nizatidine. Figure 4 A structural diagram of the membrane pool used in Embodiment 3 of the present invention is shown; Figure 5 The retention filtration process of the ultrafiltration membrane used in Embodiment 3 of the present invention is shown.

[0044] In the diagram: 1-raw water tank, 2-inlet pump, 3-agitator, 4-membrane tank, 5-ultrafiltration membrane, 6-liquid level float, 7-backwash water tank, 8-backwash pump, 9-pressure gauge, 10-negative pressure pump, 11-pressure monitoring device, 12-ceramic ultrafiltration membrane surface, 13-ceramic ultrafiltration membrane pores, 14-ultrafine powder activated carbon, 15-new pollutants. Detailed Implementation

[0045] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described in detail below. Specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0046] It should be noted that the endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0047] To facilitate understanding of the invention, certain technical and scientific terms are specifically defined below. Unless otherwise expressly defined elsewhere in this document, all other technical and scientific terms used herein have the meanings commonly understood by one of ordinary skill in the art to which this invention pertains.

[0048] In this document, the terms “comprising” or “including” are open-ended expressions, meaning that they include the contents specified in this invention, but do not exclude other aspects.

[0049] In this document, the terms “optionally,” “optionally,” or “optionally” generally refer to an event or condition that may, but may not, occur, and the description includes both cases in which the event or condition occurs and cases in which the event or condition does not occur.

[0050] According to embodiments of the present invention, a first aspect provides a method for removing typical new pollutants using a combination of ultrafine powdered activated carbon and an ultrafiltration membrane, the method comprising the following steps: (1) Add the water sample containing typical new pollutants to the ultrafiltration membrane tank and continuously add activated carbon slurry to the water sample for stirring to obtain a mixed liquid. The activated carbon used in the activated carbon slurry is ultrafine powder activated carbon, with a median particle size of 1 μm-5 μm and a specific surface area of ​​900 m². 2 / g-1500 m 2 / g, with an average pore size of 1.5 nm-2.0 nm and a total pore volume of 0.4 mL / g-0.8 mL / g.

[0051] The method provided by this invention uses ultrafine powder activated carbon with a small particle size, which can effectively remove new pollutants within a short contact time in the water plant. At the same time, in view of the potential pollution of the operating environment and dust explosion risk that ultrafine powder activated carbon itself may bring, the invention proposes to produce, transport and use ultrafine powder activated carbon in the form of carbon slurry, so as to ensure the safety of the whole process.

[0052] According to specific embodiments of the present invention, the content of ultrafine powder activated carbon in the activated carbon slurry is 10wt%-30wt%. As some specific examples, the content of ultrafine powder activated carbon in the activated carbon slurry can be 10wt%, 20wt%, 30wt%, etc. Specifically, commercially available conventional activated carbon can be processed into ultrafine powder activated carbon with a median particle size of less than 5 μm by wet grinding. It does not require drying and bagging; it can be directly prepared into a slurry with a content of 10wt%-30wt%, transported to the water plant by tank trucks, tonnes, or other containers, and stored in storage tanks for later use. When needed, it is quantitatively added using a metering pump, avoiding the safety hazards associated with dry grinding, conventional wet grinding followed by drying, and the addition of ultrafine powder activated carbon.

[0053] According to specific embodiments of the present invention, the content of ultrafine powder activated carbon in the mixture is 5 mg / L-40 mg / L. As some specific examples, the content of ultrafine powder activated carbon in the mixture can be 5 mg / L, 10 mg / L, 20 mg / L, 40 mg / L, etc.

[0054] According to specific embodiments of the present invention, the types of the new pollutants are not particularly limited. As some specific examples, the new pollutants include at least one of perfluorinated compounds, pharmaceuticals, and personal care products.

[0055] According to specific embodiments of the present invention, the type of perfluorinated compound is not particularly limited. As some specific examples, the perfluoroalkyl acid includes at least one of perfluorobutyric acid (PFBA), perfluorovalerate (PFPeA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluorobutylsulfonic acid (PFBS), perfluorohexylsulfonic acid (PFHxS), perfluorooctylsulfonic acid (PFOS), and perfluorodecylsulfonic acid (PFDS).

[0056] According to specific embodiments of the present invention, the type of pharmaceutical personal care product is not particularly limited. As some specific examples, the pharmaceutical personal care product includes at least one of ranitidine (RAN) and nizatidine (NIZ).

[0057] According to a specific embodiment of the present invention, the stirring time is 5 min-30 min. As some specific examples, the stirring time can be 5 min, 10 min, 15 min, 20 min, 30 min, etc.

[0058] According to a specific embodiment of the present invention, the stirring intensity of the stirring treatment is 500-800 in terms of hydraulic gradient. As some specific examples, the stirring intensity of the first stirring treatment in terms of hydraulic gradient (G value) can be 500, 600, 700, 800, etc.

[0059] (2) While adsorption and stirring, ultrafiltration is used to remove ultrafine powdered activated carbon from the mixture, thereby removing typical new pollutants from the water sample to be treated. Combining ultrafiltration with ultrafine activated carbon allows for the complete removal and separation of the adsorbed ultrafine activated carbon from the water through the filtration effect of the ultrafiltration membrane. This avoids the additional impact of ultrafine activated carbon on the water treatment process and ensures that the effluent turbidity meets standards. Simultaneously, the ultrafiltration process forms a denser ultrafine activated carbon filter cake layer during the retention of the ultrafine activated carbon, achieving further removal of conventional pollutants and some new pollutants. This results in a complete process suitable for waterworks, domestic sewage treatment plants, industrial wastewater treatment plants, and reclaimed water plants.

[0060] According to embodiments of the present invention, the pore size of the ultrafiltration membrane is 50-100 nm. As some specific examples, the pore size of the ultrafiltration membrane may be 50 nm, 70 nm, 100 nm, etc.

[0061] According to an embodiment of the present invention, the hydraulic retention time of the ultrafiltration process is 5-30 min. As some specific examples, the hydraulic retention time can be 5 min, 10 min, 15 min, 20 min, 30 min, etc.

[0062] According to an embodiment of the present invention, the membrane flux of the ultrafiltration process is 20-116 L / m³. 2 •h, as some specific examples, the membrane flux may be 20 L / m 2 ·h、68 L / m 2 ·h、116 L / m 2 ·h etc.

[0063] According to embodiments of the present invention, the filtration cycle of the ultrafiltration process is 30-60 min, and the backwashing interval is 30 s. As some specific examples, the filtration cycle of the ultrafiltration process is 30 min, 40 min, 50 min, or 60 min, and the backwashing interval can be 30 s.

[0064] According to an embodiment of the present invention, the backwashing flux of the ultrafiltration process is 20-146 L / m³. 2 As a specific example, the backwashing flux of the ultrafiltration process can be 20 L / m³. 2 ·h、98 L / m2 ·h、146 L / m 2 ·h etc.

[0065] According to a specific embodiment of the present invention, the method further includes: The mixture is filtered until the turbidity of the supernatant is <0.3 NTU.

[0066] Specifically, "NTU" is a standard unit for measuring the turbidity of a solution. Controlling the turbidity of the supernatant to <0.3 NTU allows for the removal of adsorbed new contaminants by ultrafine powdered carbon filtration.

[0067] like Figure 4 As shown, this invention proposes a device for removing typical new pollutants from water using a combination of ultrafine powdered activated carbon and an ultrafiltration membrane. According to an embodiment of the invention, the device includes: Raw water tank (1) is used to store water samples to be treated; Water inlet pump (2), which is connected to the raw water tank (1); Membrane tank (4), the membrane tank (4) and the inlet pump (2), when the inlet pump (2) is turned on, the water sample to be treated in the raw water tank (1) enters the membrane tank (4); A stirrer (3) is connected to the membrane tank (4) and is used to control the mixing of water sample and activated carbon slurry in the membrane tank (4) for stirring treatment. Ultrafiltration membrane (5), the ultrafiltration membrane (5) is located in the membrane tank (4) and is used to treat the water sample and activated carbon slurry in the membrane tank (4) by ultrafiltration process; Pressure gauge (9), which is connected to the ultrafiltration membrane (5); A negative pressure water pump (10) is connected to the pressure gauge (9); The activated carbon used in the activated carbon slurry is ultrafine powder activated carbon, with a median particle size of 1 μm-5 μm and a specific surface area of ​​900 m². 2 / g-1500 m 2 / g, with an average pore size of 1.5 nm-2.0 nm and a total pore volume of 0.4 mL / g-0.8 mL / g.

[0068] According to embodiments of the present invention, the above-described apparatus may further include at least one of the following additional technical features: According to an embodiment of the present invention, the apparatus further comprises: A backwash pump (8) is connected to the ultrafiltration membrane (5); Backwash water tank (7), the backwash water tank (7) is connected to the backwash water tank (7); Optionally, the device further includes: Pressure monitoring device (11), which is connected to the pressure gauge (9).

[0069] According to an embodiment of the present invention, the contaminants in the water sample to be treated include perfluorinated compounds and / or pharmaceuticals and personal care products.

[0070] According to embodiments of the present invention, the perfluorinated compound includes at least one selected from perfluorobutyric acid, perfluorovalerate, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluorobutylsulfonic acid, perfluorohexylsulfonic acid, perfluorooctylsulfonic acid, and perfluorodecylsulfonic acid.

[0071] According to an embodiment of the present invention, the pharmaceutical personal care product includes at least one selected from ranitidine and nizatidine.

[0072] According to an embodiment of the present invention, the pore size of the ultrafiltration membrane is 50-100 nm.

[0073] According to an embodiment of the present invention, the content of the ultrafine powdered activated carbon in the mixture is 5 mg / L-40 mg / L.

[0074] According to an embodiment of the present invention, the hydraulic retention time of the ultrafiltration process is 5-30 min.

[0075] According to an embodiment of the present invention, the membrane flux of the ultrafiltration process is 20-116 L / m³. 2 ·h.

[0076] According to an embodiment of the present invention, the filtration / backwashing interval of the ultrafiltration membrane tank is 30-60 min / 30 s, and the backwashing flux is 20-146 L / m³. 2 ·h.

[0077] The present invention will be explained below with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0078] Example 1 This embodiment investigates the removal effect of ultrafine powder activated carbon on perfluorinated compounds in water. The specific steps are as follows: Eleven perfluorinated compounds (PFBA, PFPeA, PFHxA, PFHpA, PFOA, PFNA, PFDA, PFBS, PFHxS, PFOS, and PFDS) standards and a phosphate buffer solution at pH 7 were added to ultrapure water to make the concentration of each perfluorinated compound in the ultrapure water 200 μg / L. Raw water is pumped into the membrane tank using a peristaltic pump. The membrane module is immersed in the membrane tank and the peristaltic pump is used to draw the produced water under negative pressure. The membrane module uses an ultrafiltration membrane with a pore size of 50 nm. The peristaltic pump is controlled to make the hydraulic retention time of the membrane tank 30 min. The membrane flux is 68 LMH.

[0079] The membrane reactor includes a water storage tank, a backwash water tank, a membrane tank, membrane modules, a magnetic stirrer, a peristaltic pump, a digital pressure gauge, and silicone tubing. The membrane filtration method used in the experiment is internal suction constant flux dead-end filtration. Raw water is pumped into the membrane reactor using a peristaltic pump. The membrane modules are submerged in the membrane tank, and the peristaltic pump draws in permeate water under negative pressure. Throughout the process, transmembrane pressure differential (TMP) data is automatically recorded by a computer via a USB interface using a digital pressure gauge. During system operation, the backwash pump is periodically activated to perform backwashing with clean water. The structure of the membrane tank is as follows: Figure 4 As shown.

[0080] During operation, ultrafine powder activated carbon slurry is continuously added to the membrane tank to maintain the concentration of ultrafine powder activated carbon in the membrane tank solution at 5 mg / L. During the filtration process, stirring is performed at a G value of 500 to increase mixing and reduce carbon powder deposition on the membrane surface; During system operation, the backwash pump is turned on periodically to backwash with clean water.

[0081] The adsorption effect of the ultrafine powder activated carbon on perfluoroalkyl acids and perfluoroalkyl sulfonic acids is shown in the figure below. Figure 3 and Figure 4 As shown, the turbidity of the effluent after ultrafiltration is maintained at 0.12 NTU.

[0082] The experimental results show that the ultrafine powder activated carbon used in this invention has a strong adsorption capacity for various types of perfluorinated compounds. Adding 5 mg / L of activated carbon can effectively adsorb and remove perfluorinated compounds within a contact time of 15 min. In particular, the removal rates of perfluorooctanoic acid and perfluorooctyl sulfonic acid, which are included in the appendix of the drinking water hygiene standards, reached 40% and 75%, respectively.

[0083] Example 2 The only difference between this embodiment and Embodiment 1 is that this embodiment investigates the removal effects of ultrafine powder activated carbon and ultrafiltration process on ranitidine and nizatidine.

[0084] Ranitidine standard and phosphate buffer solution with pH=7 were added to pure water to prepare raw water with a ranitidine concentration of 500 μg / L. Raw water is pumped into the membrane tank using a peristaltic pump. The membrane module is immersed in the membrane tank and the peristaltic pump is used to draw the produced water under negative pressure. The membrane module uses an ultrafiltration membrane with a pore size of 50 nm. The peristaltic pump is controlled to make the hydraulic retention time of the membrane tank 30 min. The membrane flux is 68 LMH.

[0085] During operation, ultrafine powder activated carbon slurry is continuously added to the membrane tank to maintain the concentration of ultrafine powder activated carbon in the membrane tank solution at 4 mg / L. During the filtration process, stirring is performed at a G value of 500 to increase mixing and reduce carbon powder deposition on the membrane surface; During system operation, the backwash pump is turned on periodically to backwash with clean water.

[0086] After 30 minutes of stable operation, the ranitidine concentration in the effluent decreased to 144.3 μg / L, with a removal rate of 71.14%. After adding ultrafine powdered carbon to the membrane tank, the turbidity increased to 11.4 NTU, while the effluent turbidity decreased to 0.08 NTU, representing a turbidity reduction of 99.29%.

[0087] The above results indicate that the ultrafine activated carbon-membrane ultrafiltration combined process has a significant removal effect on ranitidine. Since the ultrafiltration membrane itself has no effect on the removal of small molecule organic matter (ranitidine), the removal of ranitidine can be almost entirely attributed to the adsorption effect of the activated carbon. Because ultrafine activated carbon is used in this process, its adsorption rate is significantly improved, achieving the adsorption and removal of over 90% of pollutants with a hydraulic retention time of 30 min. This condition fully meets the requirements of short hydraulic retention times in actual production processes, thereby reducing the reactor footprint and minimizing the financial and time costs of infrastructure construction. Simultaneously, the turbidity of the raw water containing ultrafine activated carbon is reduced to 0.08 NTU after filtration through the ultrafiltration membrane, maintaining a turbidity level close to that of pure water. This demonstrates that the ultrafiltration process can effectively retain the ultrafine activated carbon adsorbed with pollutants, solving the additional pollution problems caused by the addition of ultrafine activated carbon and the impact on existing processes, thus forming a complete and mature new pollutant removal solution.

[0088] Example 3 The only difference between this embodiment and Embodiment 2 is that the dosage of ultrafine powdered carbon in the raw water is increased to 8 mg / L.

[0089] After 30 minutes of stable operation, the ranitidine concentration in the effluent decreased to 33.2 μg / L, with a removal rate of 93.36%. Adding ultrafine activated carbon to the membrane tank increased the turbidity to 17.4 NTU, while reducing the effluent turbidity to 0.12 NTU, representing a turbidity reduction of 99.31%.

[0090] In this embodiment, as the concentration of ultrafine powdered activated carbon increased, the removal rate of ranitidine also increased to over 90%, and the concentration of ranitidine in the treated raw water was only tens of ppm, close to the limit concentration level. Meanwhile, even with the concentration of ultrafine powdered activated carbon doubling, the turbidity of the treated effluent did not increase significantly, remaining at only 0.11 NTU, still close to the level of pure water. This indicates that the ultrafiltration membrane maintains a good retention effect for high concentrations of ultrafine powdered activated carbon without causing additional pollution problems. The above results demonstrate that the ultrafine powdered activated carbon-ultrafiltration membrane combined process developed in this invention has strong stability and can meet diverse new pollutant treatment needs. In practical applications, when facing high concentrations of new pollutants in the raw water or high removal rates of new pollutants, the process developed in this invention can further ensure effective removal of new pollutants by increasing the dosage of ultrafine powdered activated carbon, demonstrating strong adaptability and a wide range of applications.

[0091] Example 4 The only difference between this embodiment and Embodiment 2 is that the membrane flux in the ultrafiltration process is 20 LMH.

[0092] After 30 minutes of stable operation, the ranitidine concentration in the effluent decreased to 120.1 μg / L, with a removal rate of 75.98%. Adding ultrafine activated carbon to the membrane tank increased the turbidity to 18.3 NTU, while reducing the effluent turbidity to 0.07 NTU, representing a turbidity reduction of 99.62%.

[0093] In this embodiment, the membrane flux of the ultrafiltration process was reduced to 20 LMH. The results showed that the reduction in membrane flux had virtually no impact on the removal efficiency of ranitidine or the effluent turbidity. This is because membrane flux typically only affects the volume of water treated per unit time and the hydraulic retention time of the membrane tank. This demonstrates that the process developed in this study can adapt to the requirements of water treatment volume and hydraulic retention time in different practical scenarios, and has a wide range of applications.

[0094] Example 5 The only difference between this embodiment and Embodiment 3 is that the hydraulic residence time is reduced to 10 minutes.

[0095] After 30 minutes of stable operation, the ranitidine concentration in the effluent decreased to 28.1 μg / L, with a removal rate of 94.38%. Adding ultrafine activated carbon to the membrane tank increased the turbidity to 16.9 NTU, while reducing the effluent turbidity to 0.11 NTU, a turbidity reduction of 99.34%.

[0096] In this embodiment, with an ultrafine powder activated carbon dosage of 8 mg / L, the process developed in this invention still exhibited a removal rate of nearly 95% for ranitidine even as the hydraulic retention time was further reduced to 10 min. These results indicate that ultrafine powder activated carbon has an extremely fast adsorption rate, enabling the adsorption and removal of new pollutants in a short time, thus eliminating hydraulic retention time as a key factor limiting the removal of new pollutants. Therefore, the ultrafine powder activated carbon-ultrafiltration process can effectively remove new pollutants in practical applications while further reducing the hydraulic retention time in water plants. This, in turn, reduces the space and costs required for new pollutant treatment processes in water plants while ensuring effluent safety, demonstrating promising application prospects.

[0097] Example 6 The difference between this embodiment and Embodiment 2 is as follows: (1) The raw water was prepared by adding ranitidine standard to natural water taken from the surface water of a river in a certain area. The concentration of ranitidine in the raw water was 500 μg / L. (2) The dosage of ultrafine powdered carbon was increased to 16 mg / L.

[0098] After 30 minutes of stable operation, ranitidine was not detected in the effluent (the instrument's detection limit for ranitidine is 100 ng / L), and the removal rate was almost 100%. After adding ultrafine powdered carbon to the membrane tank, the turbidity increased to 24.5 NTU, and the effluent turbidity decreased to 0.23 NTU, representing a turbidity reduction of 99.06%.

[0099] The results of this embodiment show that the ultrafine powder carbon-ultrafiltration process can adapt to different raw water conditions. Even under the interference of complex components in natural water bodies, it still exhibits excellent removal capabilities for new pollutants, indicating that the process developed in this invention has strong practical application potential.

[0100] Comparative Example 1 The only difference between this comparative example and Example 3 is that the activated carbon used is commercially available conventional 200-mesh powdered activated carbon with a particle size of 78 μm.

[0101] After 30 minutes of stable operation, the concentration of ranitidine in the effluent decreased to 382.5 μg / L, with a removal rate of only 23.5%.

[0102] In this comparative example, under otherwise unchanged conditions, only the activated carbon was replaced with commercially available 200-mesh powdered activated carbon. The results showed that its effect on the treatment of new pollutants in water bodies was very limited. The concentration of new pollutants in the treated water bodies was still at a high level, indicating that conventional powdered activated carbon cannot meet the treatment requirements of new pollutants in actual production applications.

[0103] Comparative Example 2 The only difference between this comparative example and Example 5 is that no ultrafine powdered carbon was added.

[0104] Without the addition of ultrafine activated carbon, the concentration of ranitidine in the effluent was 470.5 μg / L, with a removal rate of only 5.9%. The results indicate that the ultrafiltration membrane has almost no removal effect on new pollutants. Without the addition of ultrafine activated carbon, effective treatment of new pollutants in the raw water is impossible, resulting in high levels of new pollutants in the effluent and posing a risk to drinking water health.

[0105] Comparative Example 3 The only difference between this comparative example and Example 2 is that the filter membrane assembly used is a microfiltration membrane.

[0106] The ultrafine powdered carbon used in this study has a particle size of 1-5 μm. In the microfiltration process, the pore size of the microfiltration membrane is 0.1-10 μm. The pore size of some membrane pores of the microfiltration membrane is larger than the particle size of the ultrafine powdered carbon used in this study. Therefore, the combination of ultrafine powdered carbon and microfiltration process cannot effectively retain the ultrafine powdered carbon, which will allow the ultrafine powdered carbon to penetrate the microfiltration membrane and enter the effluent, causing secondary pollution problems.

[0107] Comparative Example 4 The only difference between this comparative example and Example 2 is that the filtration membrane module used is a nanofiltration membrane or a reverse osmosis membrane.

[0108] The ultrafine powdered carbon used in this study has a particle size of 1-5 μm. In the ultrafiltration process, the pore size of the ultrafiltration membrane is 1-100 nm. This pore size is smaller than the particle size of the ultrafine powdered carbon used in this study, which can effectively retain the ultrafine powdered carbon and control the turbidity of the effluent to about 0.1 NTU, thus avoiding the problem of secondary pollutants from the ultrafine powdered carbon.

[0109] For nanofiltration and reverse osmosis processes, the pore sizes of nanofiltration membranes and reverse osmosis membranes are 0.1–1 nm and below 0.1 nm, respectively. Although these pore sizes are much smaller than the ultrafine carbon powder particle size used in this study, enabling effective retention of the ultrafine carbon powder, the denser membranes generate more energy consumption and more wastewater when treating the same volume of clean water. Specifically, the operating pressure of ultrafiltration is 0.1–0.5 MPa, and the wastewater ratio is 5–15% of the influent; the operating pressure of nanofiltration is 0.5–2 MPa, and the wastewater ratio is 15–30% of the influent; and the operating pressure of reverse osmosis is 1–10 MPa, and the wastewater ratio is 25–50% of the influent. Therefore, while nanofiltration or reverse osmosis membrane modules can effectively retain ultrafine carbon powder, they require higher operating pressures (i.e., higher energy consumption) and generate more wastewater, increasing the economic cost of water treatment. In summary, combining ultrafine powdered carbon with ultrafiltration is not only an effective way to retain ultrafine powdered carbon and remove new pollutants from water, but also the most economical technical means.

[0110] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0111] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for removing typical new pollutants from water using a combination of ultrafine powdered activated carbon and an ultrafiltration membrane, characterized in that, include: A water sample containing typical new pollutants was added to the ultrafiltration membrane tank, and activated carbon slurry was continuously added to the water sample for adsorption and stirring to obtain a mixed solution. The mixture was filtered using ultrafiltration to obtain a treated water sample. The activated carbon used in the activated carbon slurry is ultrafine powder activated carbon, with a median particle size of 1 μm-5 μm and a specific surface area of ​​900 m². 2 / g-1500 m 2 / g, with an average pore size of 1.5 nm-2.0 nm and a total pore volume of 0.4 mL / g-0.8 mL / g; The filter membrane in the ultrafiltration process membrane pool is an ultrafiltration membrane with a pore size of 50-100 nm.

2. The method according to claim 1, characterized in that, The typical new pollutants include perfluorinated compounds and / or pharmaceuticals and personal care products; Optionally, the perfluorinated compound includes at least one selected from perfluorobutyric acid, perfluorovaleric acid, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluorobutylsulfonic acid, perfluorohexylsulfonic acid, perfluorooctylsulfonic acid, and perfluorodecylsulfonic acid. Optionally, the pharmaceutical personal care product includes at least one selected from ranitidine and nizatidine.

3. The method according to claim 1, characterized in that, The content of ultrafine powder activated carbon in the activated carbon slurry is 10wt%-30wt%; Optionally, the adsorption time of the ultrafine powder activated carbon is 5-30 min; Optionally, the stirring intensity of the stirring treatment is 500-800 / s as measured by a hydraulic gradient meter.

4. The method according to claim 1, characterized in that, The content of the ultrafine powder activated carbon in the mixture is 5 mg / L-40 mg / L; Optionally, the hydraulic retention time of the ultrafiltration membrane tank is 5-30 min; Optionally, the membrane flux of the ultrafiltration process is 20-116 L / m³. 2 ·h; Optionally, the ultrafiltration process has a filtration cycle of 30-60 min, a backwash interval of 30 s, and a backwash flux of 20-146 L / m³. 2 ·h.

5. The application of ultrafine powder activated carbon in the removal of pollutants from water, characterized in that, The pollutant is a pharmaceutical product or personal care product. The median particle size of the ultrafine powdered activated carbon is 1 μm-5 μm, and the specific surface area is 900 m². 2 / g-1500 m 2 / g, with an average pore size of 1.5 nm-2.0 nm and a total pore volume of 0.4 mL / g-0.8 mL / g.

6. The application according to claim 5, characterized in that, The pharmaceutical personal care products include at least one selected from ranitidine and nizatidine.

7. A device for removing typical new pollutants from water using a combination of ultrafine powdered activated carbon and an ultrafiltration membrane, characterized in that, include: Raw water tank (1) is used to store water samples to be treated; Water inlet pump (2), which is connected to the raw water tank (1); Membrane tank (4), the membrane tank (4) and the inlet pump (2), when the inlet pump (2) is turned on, the water sample to be treated in the raw water tank (1) enters the membrane tank (4); A stirrer (3) is connected to the membrane tank (4) and is used to control the mixing of water sample and activated carbon slurry in the membrane tank (4) for stirring treatment. Ultrafiltration membrane (5), the ultrafiltration membrane (5) is located in the membrane tank (4) and is used to treat the water sample and activated carbon slurry in the membrane tank (4) by ultrafiltration process; Pressure gauge (9), which is connected to the ultrafiltration membrane (5); A negative pressure water pump (10) is connected to the pressure gauge (9); The activated carbon used in the activated carbon slurry is ultrafine powder activated carbon, with a median particle size of 1 μm-5 μm and a specific surface area of ​​900 m². 2 / g-1500 m 2 / g, with an average pore size of 1.5 nm-2.0 nm and a total pore volume of 0.4 mL / g-0.8 mL / g.

8. The apparatus according to claim 7, characterized in that, The device further includes: A backwash pump (8) is connected to the ultrafiltration membrane (5); Backwash water tank (7), the backwash water tank (7) is connected to the backwash water tank (7); Optionally, the device further includes: Pressure monitoring device (11), which is connected to the pressure gauge (9).

9. The apparatus according to claim 7, characterized in that, The contaminants in the water sample to be treated include perfluorinated compounds and / or pharmaceuticals and personal care products; Optionally, the perfluorinated compound includes at least one selected from perfluorobutyric acid, perfluorovaleric acid, perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluorobutylsulfonic acid, perfluorohexylsulfonic acid, perfluorooctylsulfonic acid, and perfluorodecylsulfonic acid. Optionally, the pharmaceutical personal care product includes at least one selected from ranitidine and nizatidine.

10. The apparatus according to claim 7, characterized in that, The ultrafiltration membrane has a pore size of 50-100 nm; Optionally, the content of the ultrafine powdered activated carbon in the mixture is 5 mg / L-40 mg / L; Optionally, the hydraulic retention time of the ultrafiltration process is 5-30 min; Optionally, the membrane flux of the ultrafiltration process is 20-116 L / m³. 2 ·h; Optionally, the filtration cycle of the ultrafiltration membrane tank is 30-60 min, the backwashing interval is 30 s, and the backwashing flux is 20-146 L / m³. 2 ·h.

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