CN101100340A - Method and device for producing pharmaceutical water by membrane separation and electrodeionization - Google Patents

Abstract

The invention discloses a method and device for producing pharmaceutical water through membrane separation and electrodeionization, belonging to pure water preparation technology. Taking urban tap water as raw water, it undergoes water treatment processes such as low-pressure membrane filtration, activated carbon adsorption, precision filtration, nanofiltration softening and desalination, deep softening of electrodeionization, deep deionization of electrodeionization, and functional charged membrane filtration to effectively remove pollutants in the water. Various inorganic ions, organic pollutants, bacteria, viruses and other microorganisms can be used to obtain pure water and ultrapure water for pharmaceutical use. Compared with the prior art, the raw water utilization rate of the water production process is effectively improved, and the water production cost is obviously reduced. The whole water production system avoids chemical regeneration softening and deionization methods, does not consume any acid and alkali, does not discharge environmentally harmful pollutants, and can adapt to a wider range of raw water conditions. , Production of pure water and ultrapure water for pharmaceutical use under the premise of environmental friendliness.

Description

Method and device for producing pharmaceutical water by membrane separation and electrodeionization

technical field

The invention relates to a method and a device for producing pharmaceutical water through membrane collection separation and electrodeionization, belonging to pure water preparation technology.

Background technique

Among the existing processes for preparing medicinal water, there are three representative types: one is the process with ion exchange technology as the core, and the other is the process of combining electrodialysis, reverse osmosis and other membrane technologies with ion exchange. The third is the process with two-stage reverse osmosis as the core. The first two are mainly used for the production of purified water (purified water). The third process is not only able to produce purified water, but also allowed to produce water for injection in some countries. With the continuous development and maturity of membrane separation technology, membrane technology has become the most versatile and economical means of pure water production. In all stages of pure water production, membrane technology is continuously used to replace traditional water treatment processes. It is a modern pure water technology. development trend.

Since any kind of membrane separation technology, like traditional separation technology, has its own specific technical boundaries and economic boundaries, and only shows its own significant advantages under some specific separation objects and working conditions, so for medical water Complicated separation problems such as the preparation of membranes require the use of membrane technology and traditional processes, as well as the optimal combination of different membrane technologies to form an efficient integrated membrane process, so as to give full play to the advantages of each separation technology and achieve the best process matching and the lowest Economical investment to optimize the process.

Invention patent ZL99111578.3 provides a production process and equipment for pharmaceutical water, which integrates four membrane separation technologies: ultrafiltration, reverse osmosis, electrodeionization, and charged microporous membrane. Raw water is pretreated by ultrafiltration, Reverse osmosis primary desalination, electrodeionization (EDI) deep desalination and charged microporous membrane terminal filtration process to obtain pharmaceutical water. The main deficiency of this design process has the following two points:

(1) Reverse osmosis is used as the pretreatment of electrodeionization, which has high cost and low water utilization rate. Especially for small-scale water production systems, the waste of raw water is high.

For pure water for medical use, a very high inorganic ion removal rate is generally not required, and the conductivity of the product water generally reaches 1 μS/cm, such as the index specified by the United States Pharmacopoeia is 1.3 μS/cm. Since the usual one-stage reverse osmosis technology cannot directly obtain pure water with a conductivity of about 1 μS/cm, it must be combined with ion exchange or electrodeionization technology. This combination can easily obtain high-purity water with a conductivity of less than 0.1 μS/cm . However, the use of reverse osmosis technology as the pretreatment of ion exchange or electrodeionization technology requires the use of high-pressure reverse osmosis pumps, high operating pressure, high power consumption and water system investment costs, which are not conducive to the popularization and application of this technology; but The more critical problem is that the use of reverse osmosis technology makes water utilization often too low. The standard water utilization rate of laboratory-scale reverse osmosis membranes with a water production rate ranging from several liters to tens of liters per hour is generally 15%. The utilization rate is only 8%. Even if the method of connecting multiple membranes in series is adopted, the water utilization rate does not exceed 60%. This has all resulted in a greater waste of water resources.

(2) With the charged microporous membrane as the terminal filtration method, the operation of the water production system is unreliable, and the product water quality is unsafe.

This special microporous filter membrane has a certain amount of positive charge on the surface of the membrane by using a specific charging agent during the production process. Because bacteria, viruses, and bacterial endotoxins in water are negatively charged, they can be adsorbed to the surface of a positively charged microporous membrane to be retained. The pore size of the membrane can reach up to 1.6 μm. However, the use of this microporous membrane also brings the following three dangers. One is that adsorption saturation is unpredictable. Since the effective positive charge on the surface of the membrane and the content of bacteria and viruses in the treated aqueous solution cannot be accurately grasped in real time, it is easy for the membrane to still be used when the adsorption is saturated. At this time, the surface of the charged membrane no longer has effective positive charges; secondly, because the membrane pore size of the charged membrane is 2-8 times larger than that of ordinary microporous membranes, when the system operating pressure is high and the water flow rate is high , electrostatic attraction may not be enough to capture bacteria and viruses, resulting in leakage; third, positively charged microporous membranes are only suitable for use in weakly acidic media. When the pH of the treatment solution is neutral to alkaline and greater than the isoelectric point of the membrane, the electrical properties of the charged groups change and the membrane becomes negatively charged. At this time, the charged membrane not only loses the ability to separate impurities by electrostatic attraction, but also the impurities adsorbed on the membrane will be eluted, which will increase the impurity content of the product water instead. The typical pH of the product water from an electrodeionization (EDI) module is neutral, with pH values approaching 7.5 under certain conditions. Under such conditions, it is unsafe to use charged microporous membranes as terminal filters.

In addition, the adsorption removal of impurities is equivalent to adsorption pollution for charged membranes. This makes it necessary to replace the new membrane immediately after the adsorption is saturated, that is, the membrane is polluted. Therefore, unlike the first three processes in the water production system, the terminal filtration process cannot run stably for a long time, which limits the degree of automation and integration of the system. , which adversely affects production efficiency.

Contents of the invention

The purpose of the present invention is to address the shortcomings of the existing water treatment process, to provide a new type of high-efficiency full-membrane integrated membrane process ultrapure water production process, which can effectively remove various inorganic ions and organic pollutants in the water, and is environmentally friendly and efficient. Production of medicinal water and ultra-pure water under the premise of high reliability, reliability and continuity can significantly improve the utilization rate of water resources and reduce the operating cost of the water system.

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

A method for producing pharmaceutical water by collecting membrane separation and electrodeionization is characterized in that it includes the following water treatment process.

1. Low-pressure membrane filtration pretreatment process of raw water

Use urban tap water that conforms to the national standard GB5749-2006 as raw water, and pass the raw water through an organic polymer ultrafiltration membrane with a membrane pore size of 0.001--0.1μm, or an inorganic ceramic ultrafiltration membrane, or a membrane with an operating pressure of 0.1-0.4MPa Organic polymer microfiltration membranes with a pore size of 0.1-0.22 μm, or inorganic ceramic microfiltration membranes, perform filtration pretreatment to intercept and remove particles, colloids, pigments, rust, bacteria and other impurities in raw water, and the retained impurities pass through the pretreatment The concentrated water in the treatment process is discharged, and the permeate is purified water.

For the present invention, when the raw water quality is poor, such as turbidity and chromaticity are high, a quartz sand filter is set before the low-pressure membrane filter unit, that is, the raw water first passes through a quartz sand filter assembly with automatic flushing function, which is filled with filter The medium is quartz sand of 0.4-1.0mm, and then enters the low-pressure membrane filter assembly, which can effectively reduce the flux attenuation of the low-pressure membrane filter.

2. Softening and desalination process of pretreated water

The water pretreated in the above step 1 is firstly filtered through adsorption and filtration of silver-infiltrated granular activated carbon or fiber activated carbon with a particle size of 20-80 mesh to remove residual chlorine, bacteria, microorganisms, and a precision filter with a filter medium of 0.2-5 μm. After removing the particles above 0.2μm, the operating pressure of 0.5-0.7MPa passes through the organic polymer nanofiltration membrane with a membrane pore size of 1-3nm to remove organic substances including divalent and above high-valent ions and molecular weight greater than 200 in water , and the treatment of impurities such as bacteria, viruses, and bacterial endotoxins to obtain nanofiltration softened water.

For the activated carbon adsorption and filtration process in the present invention, when the water output of the system is small, silver-infiltrated granular activated carbon is used. Silver-infiltrated activated carbon not only has adsorption effect on organic pollutants in water, but also has bactericidal function, which can ensure that after a certain period of use of activated carbon, bacteria will not grow due to the absence of bactericidal residual chlorine and nitrite content The problem of increased height; and the system has a large water production rate, such as more than 10m ³ /h, then use fiber activated carbon. Fiber activated carbon has a more developed microporous structure than granular activated carbon, a huge surface area and numerous functional groups, and its adsorption capacity and adsorption speed are much higher than other activated carbons. At the same time, fiber activated carbon has good strength and shape, and will not cause loose packing and over-compacting in the impact of water flow, and will not cause channeling and significant bed settlement during operation, and it is easier to desorb during regeneration, so it is more efficient. Suitable for use in large flow processing systems.

For the present invention, the types of nanofiltration membranes that can be used include cellulose acetate-triacetate cellulose (CA-CTA) membranes, aromatic polyamide composite membranes, and sulfonated polyethersulfone membranes.

3. Deep softening process of softening desalinated water

The water softened and desalinated in step 2 is filled with macroporous strong acid and strong basic anion and yang mixed bed resin in the fresh water chamber, and the volume ratio of the cation resin is 0.7-1.0, and the volume ratio of the anion resin is 0-0.3 The deep softening electrodeionization (EDI) membrane stack, under the operating condition of the working membrane pair voltage of 0.5-5V, removes divalent and high-valent ions such as Ca ²⁺ and Mg ²⁺ remaining in the softened desalinated water, as well as some other Monovalent ions, get primary pure water.

4. Deep desalination process of deeply softened water

The primary pure water obtained through deep softening in step 3 is filled with uniform mixed bed resin in the fresh water chamber, and the deep desalination electrodeionization (EDI) membrane stack in which the anion: anion resin ratio is 6:4-2:1 , under the condition that the voltage of the working membrane is 8-12V, other various charged ions and impurities remaining in the water are further removed, and a high-resistivity deep desalinated water with a resistivity of 16-18MΩ·cm is obtained.

5. Charged membrane filtration process of deep desalinated water

The water desalinated in depth in step 4 is obtained through secondary compounding with N, O-carboxymethyl chitosan as the composite material and polyethersulfone microporous membrane as the base membrane. Functional carboxymethyl chitosan/polyethersulfone (CM-CS/PES) composite ultrafiltration membrane with weakly acidic -COOH group and weakly basic _-NH2 group, or only once compounded The obtained CM-CS/PES charged microfiltration membrane removes possible particles and bacteria in the water, and finally obtains pharmaceutical water and ultrapure water without any impurities.

The devices used to realize the above method include a low-pressure membrane filter in the pretreatment unit, a nanofiltration softening and desalination device, a deep softening electrodeionization device, a deep desalination electrodeionization device and a charged membrane filtration device. The structure of the deep softening electrodeionization device mainly includes four parts: a membrane stack, a membrane stack supporting device, an electrode device, and a clamping device. The clamping device is composed of two clamping plates, tension bolts and nuts; inside the two clamping plates are positive and negative electrode devices composed of positive and negative electrode chambers and electrode separators; between the positive and negative electrodes is a The membrane stack support device is composed of rectangular hollow supporting frame plates that are adhered to each other; in the hollow cavity of the hollow supporting frame plate is a membrane stack, and the basic unit of the membrane stack is a membrane pair, each membrane pair is sequentially composed of a cation exchange membrane, a concentrated water chamber The separator, the anion exchange membrane, and the separator of the fresh water chamber are each composed of one piece, and the separator of the fresh water chamber is filled with ion exchange resin. Strong acid and strong base ion exchange resin, in which the volume ratio of cationic resin is 0.7-1.0; the thickness of the fresh water chamber partition is 3-8mm and the resin particle size is 0.4-0.9mm, and the average working membrane voltage is 1-5V.

Each membrane separation water treatment unit of the present invention is integrated into a whole to produce the following effects:

(1) It avoids the softening and deionization means of chemical regeneration, does not consume any acid and alkali, and does not discharge any environmentally harmful pollutants in the whole process;

(2) Compared with other technologies such as "two-stage reverse osmosis", "reverse osmosis/electrodeionization" and "reverse osmosis/ion exchange", the production centered on "nanofiltration/electrodeionization/electrodeionization" Water technology, the water utilization rate has been significantly improved, and the system investment has been reduced accordingly;

(3) Each component can realize long-term continuous operation, the system is easy to integrate and automate, no need to design a backup system, and the operation and maintenance costs are low;

(4) Terminal charged membrane filtration is more efficient and reliable, without adsorption and pollution saturation.

Apparently, the pure water production process of the membrane integration technology described in the present invention is not limited to pharmaceutical water. It is also applicable to the preparation of pure water in other industrial sectors and laboratory research fields such as electronics, electric power, and biology.

Description of drawings

Fig. 1 is the block diagram of the technological process of producing pharmaceutical water by membrane separation and electrodeionization provided by the present invention;

Fig. 2 is a schematic diagram of the internal structure of the deep softening electrodeionization device for realizing the invention, and Fig. 3 is a schematic diagram of the internal structure of the deep desalination electrodeionization device for realizing the present invention, in the figure:

1-Positive electrode; 2-Positive electrode chamber; 3-Desalination chamber; 4-Concentration chamber; 5-Negative electrode chamber; 6-Negative electrode; 7-Anion resin;

Fig. 4 is the specific flow chart of a kind of embodiment device provided by the present invention, in the figure:

10-raw water; 11-stop valve; 12-booster pump; 13-solenoid valve; 14-pressure gauge; 15-ultrafiltration membrane module; 16-ultrafiltration purified water; 17-ultrafiltration concentrated water; 18-activated carbon adsorption Filter; 19-precision filter; 20-nanofiltration high-pressure pump; 21-nanofiltration membrane module; 22-nanofiltration softened water; 23-nanofiltration concentrated water; Deionized electrode water; 26-deeply softened electrodeionized product water; 27-deeply softened electrodeionized concentrated water; 28-one-way valve; 29-deeply deionized electrodeion components; 30-deeply deionized electrode Water; 31-Deep deionization product water; 32-Deep deionization concentrated water; 33-Charged membrane filter module; 34-Charged membrane concentrated water; 35-Online resistivity meter; 36-Ultra Pure product water; 37-the total discharge water of the device;

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

In the example provided in Figure 4, city tap water is used as raw water, which is purified by ultrafiltration, silver-infiltrated granular activated carbon, and precision filtration. The salt unit adopts two-stage electrodeionization components, and the terminal filter is an anti-pollution charged ultrafiltration membrane component. Among them, ultrafiltration is two HYDRAcap40-LD modules connected in parallel, with a single stable water production of 1.2m ³ /h and a total water production of 2.4m ³ /h; nanofiltration uses three HL4040FF modules in series, with a water production of 1.8m ³ /h; depth The size of the fresh water chamber partition used in the softening electrodeionization device is 200*400*3mm, and the number of membrane pairs is 40. The flow rates of softened product water, concentrated water and electrode water are 1.5m ³ /h, 0.25m ³ /h and 0.05m ³ /h; the membrane logarithm of the deep desalination electrodeionization device is 36, and the flow rates of desalinated product water, concentrated water and electrode water are 1.3m ³ /h, ^{0.15m 3} /h and 0.05m ³ /h respectively ; The product water and concentrated water flows of the terminal charged membrane filtration module are 1.2m ³ /h and 0.1m ³ /h respectively. The water utilization rate of the whole system during normal operation is 71%.

A booster pump 12 and a pressure gauge 14 are arranged before the left ultrafilter. If the water pressure of the raw water 10 is high, the ultrafiltration unit will work directly; if the raw water pressure is low, the booster pump will automatically start; if the water supply is insufficient and the raw water pressure is too low, the ultrafiltration pump will automatically stop working. The system power is automatically cut off to protect the safety of the water system.

The two ultrafiltration membrane modules 15 in the pretreatment can also realize automatic mutual backwashing under the control of the PLC program through the mutual cooperation between the five solenoid valves 13, that is, in the first half cycle of backwashing, one of the components is used The purified water backwashes another component, and the flushing time can be set in advance; in the second half cycle, the opposite is true; when all backwashing is completed, all four solenoid valves except the ultrafiltration water solenoid valve are opened, and the The two ultrafiltration components perform positive flushing, and the flushing time can also be set in advance. After all flushing is completed, the concentrated water discharge solenoid valves of the two ultrafiltration components are closed, and the produced water solenoid valves are opened to enter the normal water production process. The ultrafiltration concentrated water 17 is directly discharged, and the ultrafiltration purified water 16 enters the nanofiltration unit through the activated carbon adsorption filter 18 and the precision filter 19 .

A power pump 20 and a shock-resistant pressure gauge 14 are arranged in front of the nanofiltration module. Three nanofiltration membrane modules are arranged in series in a 1-1-1 manner, and the concentrated water of the previous module is used as the water inlet of the next module. Nanofiltration concentrated water 23 is discharged. A low pressure protection switch LP is provided between the precision filter 19 and the nanofiltration pump 29 . When the upstream fails or the raw water supply fails, the low pressure switch LP will automatically sense and cut off the power supply of the nanofiltration pump and the system to protect the water system; A high pressure switch HP is set on the inter-pipeline. When the concentrated water discharge valve cannot be opened due to misoperation or accidental failure, resulting in a sudden increase in the pressure in the pipeline, the high pressure switch HP will also automatically cut off the power supply of the nanofiltration pump and the system to protect the device from damage.

At the initial stage of starting the nanofiltration pump, the concentrated water discharge solenoid valve 14 is opened to positively flush the nanofiltration system. When the flushing time is completed, the electromagnetic valve is closed, and the discharge water volume of the nanofiltration system is manually adjusted by the shut-off valve 11.

The nanofiltration demineralized water 22 is divided into three parts, and enters the downstream deep softening electrodeionization module 24, and the electrode water 25 of the latter is discharged; the concentrated water 27 is recycled to the activated carbon filter 18 through the check valve 28, and is actually a nanofiltration process. water; the deeply softened electrodeionized product water 26 is divided into three streams again and enters the deep desalination electrodeionization component 29 . The electrode water 30 of this assembly is also discharged directly, and the concentrated water 32 is also recovered before the activated carbon filter 18 through a one-way valve 28 . The product water 31 of the deep desalination electrodeionization module enters the downstream charged membrane terminal filter module 33, and finally ultra-pure product water 36 without any impurities, whose resistivity is monitored by an online resistivity meter 35 in real time. The concentrated water 34 of the charged membrane filter module 33 is also recycled to before the activated carbon filter 18 through a one-way valve 28 .

All the discharge water of the electrode water of ultrafiltration, nanofiltration and two-stage electrodeionization is finally collected and mixed into one, and discharged from the general discharge water port 37 of the device.

In this specific embodiment, the ultrafiltration membrane filtration pretreatment with self-backwashing and automatic sewage discharge functions removes particles, particles, colloids, rust, pigments, etc. in the raw water, ensuring that the pollution index of the produced water can be reduced to below 3. In addition At the same time, impurities such as organic matter and microorganisms that may cause the downstream activated carbon to quickly reach adsorption saturation are removed, thereby providing effective protection for it. Activated carbon is mainly used to remove residual chlorine that is harmful to downstream membrane processes before nanofiltration, while further reducing the content of organic matter. Although activated carbon does not have the function of automatic sewage discharge, its service life has been greatly extended due to the effective pre-ultrafiltration membrane filtration. The combined pretreatment of ultrafiltration membrane filtration and activated carbon provides reliable water inlet conditions for nanofiltration membranes and reduces the possibility of nanofiltration membranes being polluted.

The first-stage nanofiltration membrane in the system softens and removes salt, with a total desalination rate of 60%, and a removal rate of 93.6% for calcium, magnesium, hardness ions and other high-priced ions that are not conducive to downstream electrodeionization components. It removes organic matter with a molecular weight above 200 and a small amount of bacterial growth, providing the best protection for the downstream electrodeionization unit. Since the operating pressure of the nanofiltration membrane is 0.5-0.7MPa, which is significantly lower than that of the reverse osmosis membrane, the cost and power consumption of the high-pressure pump used in the nanofiltration system are correspondingly reduced compared with the reverse osmosis device with the same water production capacity. . More importantly, the concentrated water discharge of the primary nanofiltration system is 0.6m ³ /h, and the water utilization rate is 75%. If the first-stage reverse osmosis process is adopted, the highest water utilization rate is only 50%. It can be seen that the water resource utilization efficiency of the new water treatment process provided by the present invention is significantly improved.

The nanofiltration softened water is further hardened and desalinated by the special electrodeionization deep softening unit, the residual hardness ion removal rate is higher than 99%, the total desalination rate is higher than 92%, and the total content of Ca ²⁺ and Mg ²⁺ in the effluent is only 0.01 mg·L ^-1 . In this electrodeionization deep softening device, the resin filled in the fresh water chamber of the membrane stack is mainly cation exchange resin, and a small amount of anion exchange resin is doped, wherein the volume fraction of cation resin is 0.85, and the working membrane pair voltage is 2V. That is, the total membrane stack voltage is 80V. The resins filled in the fresh water chamber are D072 macroporous strongly acidic and D296 macroporous strongly basic resins with narrow particle size distribution, and the used resin particle size is 0.4-0.9mm. Using this kind of resin with a narrow particle size distribution has lower water flow resistance and hydrodynamic properties than resins with a standard particle size distribution of 0.3-1.2mm, and the desalination process can quickly reach a steady state.

The concentrated water of the electrodeionization deep softening unit is recycled to the inlet water of the upstream nanofiltration membrane filtration unit, so the unit only discharges a very small amount of electrode water, and the water utilization rate reaches 97.2%. Compared with the traditional cation exchange resin softening technology, the deep softening of electrodeionization completely avoids the periodic regeneration of the resin with chemicals, does not produce any environmentally harmful waste liquid, and keeps the process running continuously, significantly improving production efficiency and Produced water quality.

Due to the extremely low content of hardness ions in the desalinated water of the electrodeionization deep softening unit, it ensures that the downstream electrodeionization deep desalination unit will not cause scaling risks, and its not very low conductivity makes the electrodeionization deep desalination The unit can maintain an appropriate working current to ensure that the quality of the effluent water reaches the level of ultra-pure water. The resins filled in each fresh water chamber of the deep desalination electrodeionization unit are gel-type 001×7 and 201×7 mixed-bed resins, and the volume ratio of the two is 1:2. The working membrane pair voltage of the device is 10V, that is, the total membrane stack voltage is 360V, and the resistivity of the produced water exceeds 17.5MΩ·cm.

Similar to the upstream electrodeionization deep softening unit, the concentrated water of the electrodeionization deep desalination unit is also recycled to the influent water filtered by the nanofiltration membrane, and the discharged electrode water is only 50 liters per hour, so the water utilization rate reaches 96.7% . The unique two-stage electrodeionization series process in this embodiment realizes the continuous production of ultrapure water without consuming any acid and alkali, does not discharge polluting waste water, and eliminates environmental pollution.

In the terminal charged membrane filtration unit in the embodiment, the charged membrane used is a CM-CS/PES composite ultrafiltration membrane, and its polymer skeleton has both weakly acidic -COOH groups and weakly basic - The _NH2 group therefore has a large number of positive and negative charges with fixed positions at the same time, but its streaming potential is negative. When water containing bacteria and bacterial endotoxins is filtered through this charged membrane, these impurities cannot reach the surface of the membrane due to strong electrostatic repulsion, so they cannot pass through the membrane but are discharged from the concentrated water. Therefore, the functional charged membrane has very excellent anti-pollution performance, and there is no problem of adsorption/pollution saturation, so it ensures the absolute interception of microorganisms such as bacteria and bacterial endotoxins, so that it can be used continuously and for a long time, and also ensures the entire Long-term, stable and continuous operation of the water system.

Since the impurity content of the charged membrane treatment object at the terminal is already extremely low, the concentrated water accounts for a very small proportion, and it is the same as the concentrated water of the upstream two-stage electrodeionization device, which is recycled to the feed water of the nanofiltration membrane, so the unit There is actually no waste water discharge, and the water utilization rate is 100%.

The following table shows the water yield and typical water quality parameters of each process stage in the embodiment shown in Fig. 4 .

Water production m ³ /h Conductivity μS/cm Ca ²⁺ , Mg ²⁺ total content mg·L ^-1 Resistivity MΩ cm Ultrafiltration water purification 2.4 466 18.7 -- Nanofiltration softened water 1.8 190 1.2 -- Deeply softened water 1.5 14 0.010 -- Deeply demineralized water 1.3 0.056 -- 17.78   Ultra pure product water 1.2 0.056 -- 17.71

It can be seen from the water quality analysis data that the deep softening and electrodeionization process can remove more than 99% of Ca ²⁺ and Mg ²⁺ ions in nanofiltration softened water, and the total desalination rate is more than 92%. High-resistivity pure water plays a key role.

Claims (4)

1. A method for producing pharmaceutical water by membrane separation and electrodeionization, characterized in that city tap water is used as raw water, and the following water treatment processes are followed successively to obtain pharmaceutical water and ultrapure water: (1) Use organic polymer ultrafiltration membranes with a membrane pore size of 0.001-0.1 μm, or inorganic ceramic ultrafiltration membranes, or organic polymer microfiltration membranes with a membrane pore size of 0.1-0.22 μm, or the low pressure of inorganic ceramic microfiltration membranes Membrane filtration module, under the pressure of 0.1-0.4MPa, the raw water is pretreated by membrane filtration and purification; (2) adopt particle size to be 20-80 purpose silver-infiltrated granular activated carbon or fiber activated carbon adsorption assembly to carry out adsorption filtration to the water obtained through the pretreatment of step (1), then filter with the precision filter that filter medium is 0.2-5 μm, Then, under the operating pressure of 0.5-0.7MPa, the nanofiltration membrane separation process with a membrane pore size of 1-3nm is used to soften and desalinate the above-mentioned treated water; (3) Using the electrodeionization deep softening process, the nanofiltration demineralized water obtained in step (2) is deeply softened and further desalted under the operating condition that the working membrane voltage is 0.5-5V; (4) Using the electrodeionization deep desalination process, under the operating condition that the working membrane voltage is 6-12V, the deep demineralized water obtained in step (3) is deeply demineralized; (5) Perform terminal filtration on the deeply desalted water obtained in step (4) by using a charged membrane filter module. 2. The method for producing pharmaceutical water by membrane separation and electrodeionization according to claim 1, further characterized in that the charged membrane used in the charged membrane module described in step (5) is made of polyether Carboxymethyl chitosan/polyether sulfone (CM-CS/PES) made of sulfone microporous membrane as the base membrane and N,O-carboxymethyl chitosan as the composite material after one or two composites Composite film. 3. A device for producing pharmaceutical water with membrane separation and electrodeionization, including a low-pressure membrane filter, nanofiltration softening and desalination device, deep softening and electrodeionization device, deep desalination and electrodeionization device, and a charged membrane filtration device , it is characterized in that, the resin filled in each fresh water chamber of the membrane stack of the deep softening electrodeionization device is a macroporous strong acid and strong basic resin, and its particle size is 0.4-0.9mm, while the cationic resin is in the total resin volume The proportion in the middle is 70-100%. 4. The device for producing pharmaceutical water by membrane separation and electrodeionization according to claim 2, further characterized in that the concentrated water of the deep softening electrodeionization device, the deep desalination electrodeionization device and the charged membrane filtration device All are recycled to the upstream of the nanofiltration membrane softening device through a one-way valve, as the inlet water of the nanofiltration device.

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