Novel regeneration of mixed bed ion exchange resin for seawater desalination

Abstract

The present invention is directed to a novel ion exchange regeneration process wherein the regeneration does not require separation of the resin or consumption of acids and bases. A depleted strong acid / strong base mixed bed resin suitable for seawater desalination can be regenerated in situ, i.e., at a moderately elevated temperature (up to 60-80 DEG C) through high pressure (lt; 10 atm) concentrated ammonium bicarbonate (AB) solution (concentration up to 8-10 m) is washed without bead separation. Under these conditions, a relatively small amount of AB solution can be used to regenerate the depleted mixed bed resin, converting it into a form saturated with absorbed NH < 4 + > and HCO < 3-> ions. This resin can then be used for seawater desalination via direct exchange with Na + and Cl-ions, as well as other ions in seawater. By this process, the volume of drinking water produced may be at least 2-4 times the volume of the desired AB solution, which may then be discarded as a waste concentrated salt solution. By heating to 60-80 DEG C, or under reduced pressure to a lower temperature, AB dissolved in the desalinated product water can be readily thermally decomposed, which completely removes AB in the form of discharged gases NH3 and CO2, and then it is trapped and re-dissolved in cold water to reform a regenerant solution. Application of increased pressure for driving regeneration of supersaturated ammonium bicarbonate may also be performed using guided ultrasound. Waveguide ultrasound waves of appropriate frequency and intensity are transmitted inside a vessel containing a depleted mixed bed resin immersed in a concentrated or supersaturated AB solution, driving an ion exchange regeneration process. Alternatively, the pressure applied to the resin may be generated via centrifugal force generated within the rotating drum.

Description

Technical Field

[0001] The present invention relates to an improved method for the regeneration of spent mixed bed ion exchange resins, particularly for applications in seawater and brackish water desalination. The method disclosed in the present invention can also be used for the recovery of magnesium carbonate / magnesium bicarbonate precipitates at significant levels originating from seawater. In addition, the method disclosed in the present invention can be used to remove many other valuable polyvalent ions from wastewater, such as radioactive strontium (Sr 2+ ) and rare earth metals. 2+ ) and rare earth metals. Background Art

[0002] Current desalination technologies such as distillation and reverse osmosis (RO) are so energy intensive that they are often economically marginal. Seawater RO (SWRO) requires complex control systems and expensive specialized membranes. It also requires seawater pretreatment to protect the membranes from fouling, and even so, the membranes must be discarded and replaced regularly. Seawater typically has to be pressurized to 70 atm, and complex pressure recovery systems are used to reduce costs. Thermal methods are severely limited by the high heat energy demand for water evaporation enthalpy, and even with energy recovery systems, these units are only viable when associated with the availability of industrial waste heat, such as when located next to power plants and other industrial facilities.

[0003] The ancient Greeks knew how to produce "sweet" water from seawater via a simpler ion exchange method by passing seawater through viscous soil. With the development of the first plastic or polymer-based synthetic resins, the ion exchange method was modernized. This technology offers several advantages in desalination. Some of these technologies are derived from traditional resin ion exchange technologies, which have advantages such as low input pressure, simple setup, high efficiency, and do not require extensive feed water pretreatment.

[0004] Mixed bed ion exchange methods are commonly used to produce "distilled water" from slightly salty or even brackish water, but are rarely used to produce potable water from seawater. This is because the strong anion and strong cation exchange resin beads must be regenerated after exhaustion, requiring their physical separation and washing with strong acid and base solutions, which not only damages the resin polymers but also completely consumes them, at too high a cost.

[0005] Prior Art

[0006] Recently, it has been disclosed that ammonium bicarbonate (AB) solution can be used for in-situ regeneration of these mixed bed resins without the need to separate the cation and anion resins, thus giving a simpler and more effective method and increasing the resin life as these resins are not exposed to the strong acids and bases used in traditional regeneration methods. This method is disclosed in WO / 2020 / 118371. The main improvement comes from the complete elimination of the need to remove large amounts of expensive acids and bases.

[0007] Problems of the prior art

[0008] An effective commercial method must produce a significantly larger volume of desalinated water than the AB solution required to regenerate the spent mixed-bed resin. So far, this problem has not been solved.

[0009] Seawater desalination typically involves removing significant levels of dissolved Mg 2+ and SO 4 2- as well as Na + and Cl - ions, and divalent ions are more readily absorbed onto the resin, making regeneration more difficult. The present invention aims to solve the problems faced by the AB regeneration method when specifically applied to the production of drinking water from seawater.

[0010] Typical major ionic components in seawater are:

[0011] Cl - : 0.55 M, Na + : 0.47 M, Mg 2+ : 0.053 M, SO 4 2- : 0.028 M.

[0012] All of these ions can bind electrostatically to groups of opposite charge on the ion exchange resin, and they can all be removed by exposure to a higher concentration of the same type of ion, i.e., cation for cation, anion for anion. However, divalent ions must be displaced by a higher concentration of monovalent ions of the same charge.

[0013] To regenerate seawater-depleted mixed-bed resin, it is important to use a significantly higher concentration of solute, such as AB, which is possible because of the high water solubility of AB. Raising the temperature is one way to increase the concentration of the AB solution. However, raising the temperature causes AB to decompose into ammonia and carbon dioxide gases. The present invention aims to solve this problem. Summary of the invention

[0014] Ammonium bicarbonate is highly soluble in water, especially as the temperature increases. However, raising the temperature also causes the salt to decompose into ammonia and carbon dioxide gases. To solve this problem, the present invention discloses an efficient AB regeneration method that is driven by the use of increased pressure and temperature to produce a supersaturated AB solution. The pressure required for the AB regeneration method can be provided by directly applying pressure or via heating, ultrasound, or even the use of centrifugal force.

[0015] When an excess of the salt is added to an ammonium bicarbonate solution, it decomposes as the temperature rises to about 60 °C in a sealed container, and this can be used to produce NH 3 and CO2 increase in the partial pressure thereof for driving the AB regeneration of the mixed bed resin.

[0016] For example, AB starts to decompose in an aqueous solution above 40 °C, and even its solubility increases as follows:

[0017] · At 40 °C: The solubility of AB is 36.6 g / 100 g of water, which corresponds to: 4.6 m.

[0018] · At 60 °C: The solubility of AB is 60 g / 100 g of water, which corresponds to: 7.6 m.

[0019] According to the novel method of the present invention, at these higher temperatures, the partial pressure is increased to prevent the decomposition of AB.

[0020] According to Henry's law for the solubility of a gas in a solution, the pressure required to maintain a certain solubility can be estimated. Thus, for the solubility of AB at a pressure of 4 atm, the solubility will increase to approximately 8 M, reducing the volume of the regenerant solution required. Under these higher concentration and elevated temperature conditions, for resin regeneration, the productivity of the produced desalinated water increases compared to the volume of the AB regenerant solution and can exceed the requirements of commercial methods. This results in the production of excess desalinated water during the process. When the supersaturated AB solution is heated in a pressure vessel, the decomposition of AB increases the partial pressures of ammonia and carbon dioxide and drives the regeneration process.

[0021] This discovery of the present invention is also strongly supported by a very important consideration based on a fundamental thermodynamic law known as Le Chatelier's principle. Applied to the pressurized regeneration method, this general principle means that the increased (partial) pressures of NH3 and CO2 gases will drive the adsorption of NH 4 + and HCO 3 - ions onto the resin, thereby removing them from the solution, because they are always in dynamic equilibrium with ammonia and carbon dioxide gases, which is why pressure needs to be applied to prevent the decomposition of AB.

[0022] Le Chatelier's principle predicts that this system will react to counteract the applied pressure, and it can only do this by forcing more of these ions into the resin. In contrast, Na + 、Cl - and Mg 2+ and SO 4 2- ions do not have a pressure change related to whether they are in solution or on the resin, and thus are not driven in some way by the application of pressure.

[0023] In addition, it should also be recognized that due to NH 4+ and HCO 3 - ions are absorbed onto separate beads (i.e., anion and cation exchange beads) in the mixed bed, so the different absorbed ions are physically separated by about 1 mm and thus cannot decompose. This is because in order to decompose into two gases, a water molecule must be extracted from the NH 4 HCO 3 molecule.

[0024] This makes pressure AB regeneration ideal for mixed bed resins. Once AB is absorbed by the resin, reducing this pressure will not make much difference, and the NaCl concentrate can be discharged, especially if the temperature is allowed to return to room temperature before the pressure is released.

[0025] Any strong acid-base mixed bed resin can be used as the resin in the method disclosed in the present invention. One of the resins suitable for implementing this invention is MonoPlus SM 1000KR resin, which is a ready-to-use mixed bed that includes strongly acidic gel-type cation and strongly basic gel-type anion exchange resins in a fully regenerated form. In this mixed resin, the anion exchange capacity is half of the cation exchange capacity, so they are mixed in a ratio of 2:1. The functional groups of the anion exchanger contain quaternary ammonium (quats), and the cation exchanger contains sulfonate groups.

[0026] This new method is equivalent to separating the products generated in a chemical reaction, which is often used to drive the reaction forward and prevent the reverse reaction. It should be noted that although the present invention focuses more on the most difficult problem of seawater desalination, this method will also significantly improve the productivity of brackish water.

[0027] In addition, it has also been observed that the new AB regeneration method of the present invention produces magnesium carbonate / magnesium bicarbonate precipitate as a by-product, which is derived from a significant level of Mg in the seawater absorbed by the resin 2+ . Similarly, the method disclosed in the present invention can be used to remove many other valuable polyvalent ions (such as radioactive strontium (Sr 2+ )) and rare earth metals) from contaminated wastewater.

[0028] Essentially, the new method of the present invention includes the following main stages:

[0029] Stage 1: A continuously flowing ionic solution (such as seawater) passes through a mixed bed, strong acid and strong base resins, where the ion exchange groups are initially saturated with NH 4 + and HCO 3 - ions, preferably by an upward flow of the supplied water, to produce a solution containing essentially only desorbed NH 4+ and HCO 3 - drinking water (volume Vp) containing ions.

[0030] Stage 2: Heat the product water to 60 - 80 °C to completely remove the AB solute in the form of CO 2 and NH 3 gases to produce the final product water (volume Vp); or at a lower temperature under reduced pressure.

[0031] Stage 3: Collect the released gases by initially dissolving them in cold water, and then further concentrate them by dissolving under pressure (up to 10 atm) and heating the solution to up to 80 °C to produce an AB regeneration solution (volume Vr) up to 8 m.

[0032] Stage 4: Then the heated regenerant solution is fed under pressure into a container (ion exchange column) containing seawater - depleted resin. The container is sealed and continuously rolled or shaken to allow mixing for a period of time until the pressure in the container drops to a lower equilibrium value, which indicates that NH 4 + and HCO 3 - ions have replaced the seawater ions absorbed by the resin. When the supersaturated AB solution is heated in a pressure vessel, the decomposition of AB increases the partial pressures of ammonia and carbon dioxide, thus driving the regeneration process.

[0033] Stage 5: Then reduce the temperature and pressure in the resin container to ambient conditions, and allow the salt concentrate to completely drain from the resin (or be discharged, for example, by pumping a gas stream) and be discarded (volume approximately Vr).

[0034] Then the method repeats from Stage 1. Description of the Drawings

[0035] Although any other form of the present invention falls within the scope of the disclosed methods and devices, the following describes specific embodiments of the present invention by way of example only with reference to the attached Figures 1 to 3 drawings.

[0036] Figure 1 is a schematic diagram of a desalination method according to the present invention, including a regeneration step using a supersaturated ammonium bicarbonate solution under pressure. Figure 1 The reference numerals used in the

[0037] 101 - ion exchange container

[0038] 102 - ammonium bicarbonate decomposition unit

[0039] 103 - Unit for preparing supersaturated ammonium bicarbonate solution

[0040] V1 - Seawater isolation valve

[0041] V2 - Product water with AB isolation valve

[0042] V3 - Supersaturated AB solution isolation valve

[0043] V4 - Waste salt concentrate isolation valve

[0044] Figure 2 is a schematic diagram showing the standard wave characteristics.

[0045] Figure 3 is a schematic embodiment for guiding ultrasonic waves in a pipeline container for ion exchange. In this figure, item 1 is a tubular container, which serves as an ion exchange unit that can be used vertically or horizontally. Item 2 represents an ultrasonic transducer or emitter. Item 3 is a strong acid-strong base mixed bed resin. As Figure 3 shown, this pipeline container can be used horizontally or vertically. Detailed implementation mode

[0046] The following refers to Figure 1 to describe the arrangement of using the seawater desalination equipment of the present invention:

[0047] In Figure 1 , item 101 is an ion exchange container, or a column filled with strong acid-strong base mixed bed resin. In the operation cycle, the resin is in the form of ammonium bicarbonate (AB). During the operation cycle, valves V3 and V4 are in the closed position. Valves V1 and V2 are in the open position.

[0048] In the operation stage, seawater is pumped into the ion exchange column 101 via valve V1. When the seawater passes through the column, the Na + and Cl - ions in the seawater are exchanged with the ammonium ions and bicarbonate ions in the resin.

[0049] The product water containing AB leaves the ion exchange column 101 via valve V2 and enters the container 102 for decomposing the AB solution. The decomposition of AB is carried out by heating the container 102 to a suitable temperature (about 60 °C).

[0050] The clean water generated by the decomposition of AB leaves the container. The CO 2 and NH 3 gases generated during the decomposition process are guided to the container 103, where it combines with some of the clean water generated by the decomposition process.

[0051] In the container 103, CO 2 , NH 3Water and are subjected to a relatively high temperature (60 °C) and pressure (greater than 1 atm) to produce a supersaturated AB solution. This supersaturated AB solution is pumped under pressure via valve V3 into an ion exchange vessel or column 101 (while V1 and V2 are in the closed position).

[0052] The supersaturated AB solution passes through the resin in the ion exchange column under pressure, exchanging with Na attached to the resin + and Cl - ions for ammonium ions and bicarbonate ions. The concentrated waste salt solution is discharged via valve V4.

[0053] After removing all the Na + and Cl - ions, the cycle is changed back to the operating cycle by pumping seawater through the ion exchange column 101 again.

[0054] For a typical seawater supply, the productivity (Vp / Vr) can be targeted in the range of 2 - 4.

[0055] Another preferred embodiment of the present invention is that the AB regeneration process can be driven by a positive pressure increase that acts only in one direction; such that even when the pressure is decreased or reversed, no reverse ion exchange reaction occurs. This is because the anion and cation exchange beads are physically separated, which prevents thermal or low-pressure decomposition of AB, which can only occur via the combined salts. This embodiment is based on the observation that the pressure-driven displacement of Na 4 + and Cl 3 - ions by NH + and Cl - ions on the ineffective mixed bed resin can only act in one direction. This is because AB can only decompose in the combined salt state. Even under the application of negative pressure, the individual ions cannot decompose because they are physically separated onto two different ion exchange beads (i.e., anion and cation exchange beads).

[0056] This embodiment of the present invention uses guided ultrasonic waves of appropriate frequency and intensity, transmitted along the interior of the container housing the ineffective mixed bed resin immersed in the concentrated or supersaturated AB solution, to apply pressure in one direction. This embodiment can be used to substantially reduce the need to raise the background temperature and increase the pressure during the regeneration process, provide significant energy savings, and also reduce the required operating time. At the end of the process, AB can be easily recycled by low-temperature thermal decomposition (by heating to 60 - 80 °C), which removes AB completely in the form of the emission gases NH 3 and CO 2 and then the gases are captured and redissolved in cold water to reform the regenerant solution.

[0057] Ultrasonic waves can be used to effectively provide an appropriate transient pressure source to generate a pressure increase acting on the exchange reaction in only one direction. This pressure increase, passing through the ineffective resin immersed in the concentrated or supersaturated AB solution, will assist or even drive the regeneration in the low-energy process. Ultrasonic waves are pressure waves with frequencies above the human audible range of 20 kHz. The traveling speed of these waves depends on the medium and is approximately 1500 m / s in seawater. Human imaging ultrasound scanners operate at relatively high frequencies of about 10 MHz. The waveform of such waves is shown in Figure 2 it.

[0058] The speed of ultrasonic waves is obtained by multiplying the frequency by the wavelength. Thus, the wavelength at 40 kHz is: 1500 / 20000 = 0.075 m or 7.5 cm, and the wavelength at 10 MHz (such as that of a human scanner) is: 1500 / 107 = 0.00015 m or 0.15 mm. This indicates that a wide range of frequencies and wavelengths can be used to drive the transient increase in local pressure in the AB ion exchange method.

[0059] Ultrasonic waves have been used to detect fluid-filled pipes using point-by-point defect detection by bulk ultrasonic waves or long-range inspection by guided waves. Guided wave ultrasonic testing (GWUT) is more suitable for large-area damage detection. Guided waves can propagate long distances along the structure under test and query the entire structure in a short time. Depending on the required application, there are many different geometries for generating waveguide configurations. Such guided waves can be used in the method described in the present invention.

[0060] An ultrasonic transducer converts alternating current (AC) into ultrasonic waves and vice versa. Transducers typically use piezoelectric transducers or capacitive transducers to generate or receive ultrasound. Piezoelectric crystals can oscillate in response to an applied voltage signal over a wide frequency range. Such oscillations can generate ultra-high-frequency sound waves. As required, the piezoelectric transducer can be assembled on the outer wall of the container or directly in contact with the fluid inside the container.

[0061] Figure 3 is a schematic diagram of a guided ultrasonic waveguide configuration for use with a pipe container according to one aspect of the present invention.

[0062] As Figure 3 shown, the non-axisymmetric partial loading of small element transducers in the pipe excited multiple modes (longitudinal and flexural guided waves). The excited flexural modes have displacement fields in all three directions (radial, circumferential, and axial). When the excitation source inputs a wide range of frequencies, more flexural guided wave modes are generated, and their different wavelengths are conducive to generating a wide range of forced, pressure-driven interactions suitable for supporting this pressure-driven ion exchange method in the entire enclosed fluid and resin mixture.

[0063] The method of the present invention for desalination of seawater or brackish water has been described above. Similarly, this method can be used to purify any other contaminated wastewater for removing polyvalent ions such as radioactive Sr 2+ and rare earth metal ions.

[0064] Although various embodiments of the present invention have been described above, it should be understood that they are presented by way of example only and not as limitations. It will be apparent to those skilled in the relevant art that various changes can be made in form and detail to adapt to different situations without departing from the spirit and scope of the present invention. Therefore, the present invention should not be limited by any of the above exemplary embodiments.

Claims

1. A method for desalination of seawater or brackish water, comprising the steps of: a. Continuous flowing seawater or brackish water passes through a mixed bed ion exchange column containing strong acid and strong base resins, where the ion exchange groups are initially saturated with NH 4 + and HCO 3 - ions to produce substantially desalted water containing desorbed NH 4 + and HCO 3 - ions until the resin is exhausted; b. Heat the desalinated water containing desorbed NH 4 + and HCO 3 - ions to a temperature between 60 - 80 °C or to a lower temperature by heating under reduced pressure to completely remove the ammonium bicarbonate solute as CO 2 and NH 3 gases to produce desalinated product water; c. Combine the released gases CO 2 and NH 3 with a portion of the produced desalinated product water to prepare an ammonium bicarbonate solution; d. Concentrating the ammonium bicarbonate solution by subjecting it to a higher pressure and temperature to produce a supersaturated ammonium bicarbonate regenerant solution; e. Pass the supersaturated ammonium bicarbonate regeneration solution, and exchange the ammonium and bicarbonate ions in the regeneration solution with the sodium and chloride (as well as Mg 2+ and SO 4 2- ) ions in the exhausted resin. At the same time, heat to decompose the supersaturated ammonium bicarbonate regenerant to increase the ammonia and carbon dioxide partial pressures and drive the regeneration process, so as to regenerate the exhausted resin in the ion exchange column; f. Discharging the concentrated sodium chloride solution from the ion exchange column; and g. Repeating steps a to f.

2. The method according to claim 1, wherein the volume of the produced desalinated product water is higher than the volume of the ammonium bicarbonate regeneration solution used, resulting in a net surplus of desalinated product water.

3. The method according to claim 2, wherein the concentration of the ammonium bicarbonate solution is carried out at a pressure between 1 and 10 atm and a temperature between 40°C and 80°C to produce a regenerant solution having an ammonium bicarbonate concentration of at most 8 molar.

4. The method according to claim 3, wherein the heated regenerant solution is fed under pressure into an ion exchange column containing the depleted resin, and the ion exchange column is continuously rolled or shaken to allow mixing for a period of time until the pressure in the vessel drops to a lower equilibrium value, indicating that NH 4 + and HCO 3 - ions have replaced the seawater ions absorbed by the resin.

5. The method according to claim 4, wherein the temperature and pressure in the ion exchange column are reduced to ambient conditions before discharging the concentrated sodium chloride solution.

6. The method according to claim 5, wherein the regeneration process is driven by a positive pressure increase acting only in one direction.

7. The method according to claim 6, wherein guided ultrasonic waves are used to instantaneously apply a positive pressure increase to pressurize all regions within the seawater-depleted mixed bed ion exchange resin in the concentrated or supersaturated solution of ammonium bicarbonate immersed in the ion exchange column, thereby driving the resin regeneration process via ion exchange.

8. The method according to claim 7, wherein the frequency of the guided ultrasonic waves is in the range of 20 kHz to 20 MHz.

9. The method according to any one of claims 1 to 8, wherein magnesium in the form of magnesium carbonate or magnesium bicarbonate precipitate is recovered as a by-product derived from Mg present at a significant level in seawater absorbed by the resin. 2+ ​ 10. A method for treating wastewater containing dissolved electrolytes, comprising the steps of: a. The continuously flowing electrolyte wastewater passes through a mixed-bed ion exchange column containing strong acid and strong base resins, where the ion exchange groups are initially saturated with NH 4 + and HCO 3 - ions to produce an ammonium bicarbonate solution substantially containing desorbed NH 4 + and HCO 3 - ions until the resin is exhausted; b. Heat the ammonium bicarbonate solution produced in the previous step to a temperature between 60 - 80 °C or heat it under reduced pressure to a lower temperature to completely remove the ammonium bicarbonate solute as CO 2 or NH 3 gas to produce treated product water; c. Combine the released gases CO 2 and NH 3 with a portion of the treated product water to prepare an ammonium bicarbonate solution; d. Concentrating the ammonium bicarbonate solution by subjecting it to a higher pressure and temperature to produce a supersaturated ammonium bicarbonate regenerant solution; e. Passing the supersaturated ammonium bicarbonate regenerant solution, exchanging the ammonium and bicarbonate ions in the regenerant solution with the electrolyte ions in the depleted resin, and heating to decompose the supersaturated ammonium bicarbonate regenerant to increase the ammonia and carbon dioxide partial pressures and drive the regeneration process, thereby regenerating the depleted resin in the ion exchange column; f. Discharging the concentrated waste solution from the ion exchange column; and g. Repeating steps a to f.

11. The method according to claim 10, wherein the volume of the produced treated product water is higher than the volume of the ammonium bicarbonate regeneration solution used, resulting in a net surplus of treated product water.

12. The method according to claim 11, wherein the concentration of the ammonium bicarbonate solution is carried out at a pressure between 1 and 10 atm and a temperature between 40°C and 80°C to produce a regenerant solution having an ammonium bicarbonate concentration of at most 8 molar.

13. The method according to claim 12, wherein the heated regenerant solution is fed under pressure into an ion exchange column containing the depleted resin, and the ion exchange column is continuously rolled or shaken to allow mixing for a period of time until the pressure in the vessel drops to a lower equilibrium value, indicating that NH 4 + and HCO 3 - ions have replaced the electrolyte ions absorbed by the resin.

14. The method according to claim 13, wherein the temperature and pressure in the ion exchange column are reduced to ambient conditions before discharging the concentrated waste electrolyte solution.

15. The method according to claim 14, wherein the regeneration process is driven by a positive pressure increase forcing the ion exchange reaction to occur only in one direction.

16. The method according to claim 15, wherein guided ultrasonic waves are used to apply a positive pressure increase to instantaneously pressurize all regions within the depleted mixed-bed ion exchange resin in a concentrated or supersaturated solution of ammonium bicarbonate immersed in an ion exchange column, thereby driving the resin regeneration process via ion exchange.

17. The method according to claim 16, wherein the frequency of the guided ultrasonic waves is in the range of 20 kHz to 20 MHz.

18. The method according to claims 10 to 17, for removing radioactive strontium (Sr 2+ ) or rare earth metals from wastewater.

19. An apparatus for treating an ionic solution by ion exchange, which comprises: ·Mixed bed ion exchange column containing strong acid and strong base resins, wherein the ion exchange groups are initially saturated with NH 4 + and HCO 3 - ions to produce treated water substantially containing desorbed NH 4 + and HCO 3 - ions until the resin is exhausted; · A component for heating the treated water containing desorbed NH 4 + and HCO 3 - ions to a temperature between 60 - 80 °C or heating under reduced pressure to a lower temperature to completely remove the ammonium bicarbonate solute as CO 2 and NH 3 gas to produce product water; · A component for combining the released gases CO 2 and NH 3 with a part of the produced product water to prepare a component for an ammonium bicarbonate solution; · A component for concentrating the ammonium bicarbonate solution by subjecting it to a higher pressure and temperature to produce a supersaturated ammonium bicarbonate regenerant solution; · A component for transferring the supersaturated ammonium bicarbonate regenerant solution, exchanging the ammonium and bicarbonate ions in the regenerant solution with the ions in the depleted resin, while heating to decompose the supersaturated ammonium bicarbonate regenerant to increase the ammonia and carbon dioxide partial pressures and drive the regeneration process to regenerate the depleted resin in the ion exchange column; · A component for discharging the concentrated waste solution from the ion exchange column, using the applied pressure or residual pressure from the regeneration process.

20. The apparatus according to claim 19, further comprising a component for applying an instantaneously acting pressure to pressurize all regions within the mixed-bed ion exchange resin in a concentrated or supersaturated solution of ammonium bicarbonate immersed in an ion exchange column, thereby driving the resin regeneration process via ion exchange.

21. The apparatus according to claim 20, wherein the component for applying the instantaneously acting pressure is either guided ultrasonic waves having a frequency range of 20 kHz to 20 MHz or by using a rotating drum to generate a centrifugal pressure on the resin.

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