Degassing Unit

Abstract

A degassing module is described that can be used with a sorbent regeneration cartridge. The degassing module can include an air inlet port, a fluid outlet port, a gas outlet port, first and second channels disposed within an internal chamber, a port connecting the first and second channels, and a hydrophobic membrane positioned above the second channel. The first channel can be in fluid communication with the air inlet port, and the second channel can be in fluid communication with the fluid outlet port. In some embodiments, each of the first and second channels can have a helical configuration.

Description

[Technical field]

[0001] (CROSS REFERENCE TO RELATED APPLICATIONS) This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 194,834, filed May 28, 2021, which is expressly incorporated by reference in its entirety herein for all purposes.

[0002] The present invention relates to cartridges useful in dialysis. In particular, the present invention relates generally to degassing of regenerated dialysate fluid. [Background technology]

[0003] In the United States, it is estimated that more than one in seven adults (about 15% of U.S. adults) suffer from chronic kidney (or renal) disease. In people with chronic kidney disease, their kidneys no longer cleanse their blood and healthy kidneys. Thus, toxic waste products and excess fluid build up in the body. Dialysis is a treatment that removes the waste products and excess fluid that builds up in the blood as a result of kidney failure. Chronic renal failure is when kidney function has deteriorated to about 25% of normal. This amount of deterioration causes significant changes in blood chemistry, and is the time when people feel too unwell and seek medical treatment. If medical treatment is sought in time, the progression can be slowed. Late stage chronic renal failure is when kidney function has decreased to 15%. End stage renal failure is when kidney function is at 5% of normal. Death will most likely result from the condition without treatment at this point.

[0004] While there is no current cure for kidney disease, several forms of treatment do exist. One treatment is transplantation, where a human kidney is surgically placed in the body and connected to the bladder. After transplantation, daily drug treatments are required to prevent the body from rejecting the transplanted kidney. Another treatment is peritoneal dialysis (PD). For this treatment, a thin salt water solution called dialysate, which contains glucose and electrolytes, is placed into the peritoneal cavity. Because there is an abundant blood supply to this cavity, urea and other toxins from the blood and fluid are transferred into the dialysate, thereby cleaning the blood. The dialysate is then drained from the peritoneum. Later, "fresh" dialysate is placed back into the peritoneum.

[0005] Another form of treatment is hemodialysis. It is a method of blood purification in which blood is continuously removed from the body and passed through a dialyzer (artificial kidney), where metabolic waste and excess water are removed and pH and acid / base balance are normalized. The blood is returned to the body at the same time. The dialyzer is a small disposable device consisting of a semi-permeable membrane. The membrane allows waste, electrolytes, and water to cross, but restricts the passage of large molecular weight proteins and blood cells. Blood is pumped on one side of the membrane as dialysate is pumped in the opposite direction on the other side of the membrane. The dialysate is highly purified water with added salts and electrolytes. The machine is a control unit that works to pump the blood and dialysate and control their pressure, temperature, and electrolyte concentration. The average length of one hemodialysis treatment is about 3.5 hours.

[0006] Several types of hemodialysis exist, including single-pass and sorbent systems. Single-pass hemodialysis is the most common treatment for kidney disease. These devices are called single-pass because the dialysate (cleansed solution) passes once through the blood in the dialyzer and is then disposed of. Single-pass dialysis machines generally require (1) a water source capable of delivering at least 1,000-1,500 ml / min (assuming a 50% rejection rate by the reverse osmosis (RO) system), (2) a water purification system sufficient to provide a continuous flow of 500-800 ml / min of purified water, (3) an electrical circuit of at least 15 amps to pump and heat 500-800 ml / min of water, and (4) a bed drain or any other receiver capable of receiving at least 500 ml / min of used dialysate and rejected water from the RO system.

[0007] The sorbent dialysis system does not require a continuous water source, a separate water purification machine, or bed drains because the system continually regenerates a small amount of dialysate and incorporates a water treatment system within the machine. Thus, the sorbent system is portable. The sorbent system can use six liters of water from which dialysate is made for the entire treatment. The sorbent system uses a sorbent cartridge that functions both as a water purifier and as a means to regenerate used dialysate into fresh dialysate. The infusate system works in conjunction with the sorbent system to properly balance the electrolyte composition of the regenerated dialysate.

[0008] Currently, there are several types of multi-layer sorbent cartridges that are used in dialysis machines to remove uremic toxins from a patient's blood and reuse the dialysis solution through recirculation. However, these sorbent dialysis systems do not efficiently remove uremic toxins at high volumes or with high electrolyte stability.

[0009] In a sorbent dialysis system, the process of removing urea using urease and zirconium phosphate generates a fluid composition that exits the sorbent cartridge and has a lower pH than the standard range used in bicarbonate dialysate. The sorbent devices described above use a high pH final layer in the sorbent cartridge of zirconium oxide and zirconium carbonate. However, these devices have limitations on the dialysate flow rate and the length of the dialysis treatment, which must be traded off against increasing the total mass of the final layer to raise the pH. Alternatively, increased pH can be used in the zirconium phosphate layer. Other metal phosphates of iron (III), titanium (IV), and cerium (IV) suffer from similar challenges. However, it results in excess sodium and reduced removal capacity for ammonium generated by the urea reaction with urease. Other processes use sodium bicarbonate as an added chemical to the sorbent outlet stream, but these systems have resulting pH levels well below standard bicarbonate dialysis or require specialized systems for removal of the majority of the dissolved CO2 gas in the fluid stream exiting the sorbent cartridge.

[0010] Some devices remove CO2 by pumping the dialysate into an open chamber and allowing the gas bubbles to float to the top of the chamber. However, the system simply relies on the gas naturally escaping the fluid while agitating the fluid with a pump. Such systems offer little control over the degassing process. Additionally, the fluid reservoir is open to the atmosphere, which presents potential sterility challenges, extra short-term maintenance, and long-term maintenance challenges.

[0011] Other degassing systems that remove CO2 under vacuum are not ideal because they require a lot of energy to operate. Additionally, a lot of water evaporates under these vacuum systems, which concentrates the dialysate and raises the sodium level. They also generate a moisture stream that needs to be collected and disposed of. Vacuum systems also add higher vacuum pressure requirements to the system tubing and pumps. Membrane degassing systems require large surface areas and expensive membranes, which are prone to fouling challenges. Degassing using chemical reactions or adsorbents adds significant cost, and most feasible adsorbents for CO2 also filter out undesirable chemicals. Summary of the Invention [Means for solving the problem]

[0012] Therefore, it would be beneficial in the field of dialysis to create a sorbent regeneration system that includes an effective method of removing excess CO2 gas from the regenerated fluid while also raising the pH of the fluid to an acceptable level. [Brief description of the drawings]

[0013] [Figure 1A] FIG. 1A is an exemplary schematic diagram of an adsorbent cartridge with a degasser module.

[0014] [Figure 1B] FIG. 1B is a cross-section of an exemplary sorbent cartridge with a degasser module.

[0015] [Figure 2A] FIG. 2A is a bottom perspective view of a portion of a degasser module.

[0016] [Figure 2B] FIG. 2B is a top perspective view of a portion of the degasser module.

[0017] [Figure 3A] FIG. 3A is a perspective view of a degasser module.

[0018] [Figure 3B] FIG. 3B is a cross section AA' of the degasser module shown in FIG. 3A.

[0019] [Figure 3C] FIG. 3C is a cross section BB' of the degasser module shown in FIG. 3A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] (summary) A sorbent cartridge including a degassing module is described, which can be used to regenerate dialysate to be used in a dialysis system.

[0021] Sorbent regeneration degassing may be accomplished by introducing a stream of air, which may be substantially free of CO2, into the regenerated dialysate. The air stream may have approximately the same flow rate as the liquid flow rate. The combined air-liquid fluid may then be exposed to a hydrophobic membrane where the gas is free to exit the system.

[0022] The fluid may be directed to flow through several fluidic channels. In the first fluidic channel, the fluid may mix with ambient air, lowering the partial pressure of CO2 in the fluid. In the second fluidic channel, as the fluid flows through the long channel, at least a portion of the gas contained in the fluid dissipates out of the fluid through a hydrophobic membrane.

[0023] (Detailed Description) In dialysis therapy, the dialysis machine acts as an artificial kidney to remove uremic toxins, balance ionic molecules, and balance pH for patients who lack healthy kidneys to perform renal tasks. When a multi-layer cartridge is used instead of a large amount of water, the cartridge is not only responsible for removing uremic toxins, but also for balancing ionic salts and pH.

[0024] A hemodialysis system incorporating a dialysate generator is described in US 2021 / 0128807, which is expressly incorporated by reference in its entirety for all purposes. Various embodiments of a sorbent regeneration system including a sorbent cartridge described herein may be incorporated into the system described in US 2021 / 0128807 in place of the dialysate generator.

[0025] The sorbent regeneration cartridge 200 may contain multiple layers of components for purifying the dialysate. The cartridge 200 may contain at least a layer of urease and a layer or layers of zirconium phosphate or other metal phosphates (such as iron(III), titanium(IV), and cerium(IV) which may be in different forms). During regeneration dialysis, the used dialysate moves upward through the layers of the cartridge 200. The urease converts urea to ammonium carbonate. The ammonia and ammonium ions are then converted to H + and Na + The carbonate from the urea hydrolysis is then removed by a layer or layers of zirconium phosphate (or metal phosphate) in exchange for the ions. + Combined with bicarbonate (HCO3 - ) and carbonic acid (H2CO3). Carbonic acid is an unstable organic acid, most of which quickly decomposes into water and carbon dioxide molecules (CO2). The CO2 gas bubbles can then be vented from the cartridge using the degassing unit 300.

[0026] The sorbent cartridge 200 has two processes that generate excess carbon dioxide (CO2) gas. The decomposition of urea (CON2H4) by the urease enzyme follows the reaction: CON2H4+H2O→CO2+2NH3 CO2+2NH3H2O→0.5CO3 2- HCO3 1- +2NH4 1+

[0027] The chemical equilibrium is between carbon, ammonia (NH3), and ammonium (NH4 + ) may have different amounts of each form. xCO2 ←→ yHCO3 1- ←→zCO3 2- aNH3←→bNH4 1+

[0028] When the spent dialysate, which contains ammonia (NH3), is then passed through a zirconium phosphate (or other metal phosphate) cation adsorbent, the following reaction occurs, which results in the production of carbonic acid (H2CO3): Zr(HPO4)2+0.5CO3 2- HCO3 1- +2NH4 1+ ←→Zr(NH4PO4)2+HCO3 1- +H2CO3 To a lesser extent, sodium bicarbonate and sodium chloride can also be exchanged to produce carbonic acid. Zr(HPO4)2+NaHCO3+NaCl←→Zr(NaPO4)(HPO4)+H2CO3+NaCl

[0029] Carbonic acid (H2CO3) is not stable and tends to decompose into carbon dioxide (CO2) according to the following equation: H2CO3→CO2+H2O

[0030] Thus, treatment of the dialysate with zirconium phosphate or other metal phosphates (such as iron(III), titanium(IV), and cerium(IV)) results in an acidified dialysis solution. Some of the CO2 present may be purely in the gas phase, and another portion of the CO2 present may be dissolved in the dialysate exiting the sorbent cartridge 200. The portion of the CO2 dissolved in the dialysate may be very high since the partial pressure of CO2 in the sorbent cartridge is very high. This relationship is known as Henry's Law:

number

[0031] Henry's law states that a constant (H CP ) is the concentration of dissolved gas (C i ) to the partial pressure of the same dissolved gas (P i ). Thus, methods for removing excess CO2 may focus on lowering the partial pressure of CO2 in the dialysate.

[0032] As seen in FIGS. 1A-1B and 3A, a degasser module or unit 300 may be disposed above the sorbent cartridge 200. The degasser 300 may include a container 316 having a base 310 and a cover 314. The base may have a groove 312 configured to hold an O-ring 322, which may frictionally engage the outer wall 296 of the sorbent cartridge 200. The container 316 may include at least two fluid channels, a lower fluid channel 330 and an upper fluid channel 340, that are configured to direct the flow of a fluid, such as regenerated dialysate. The base 310 of the degasser unit 300 may be located adjacent to or in contact with a particle-retaining filter 298 disposed above the sorbent bed 294, such that the lower fluid channel may contact the particle-retaining filter 298 at the top of the sorbent bed 294. Thus, the lower fluid channel 330 can contact fluids and gases being pumped from the bottom to the top of the sorbent bed 294 of the sorbent cartridge 200 .

[0033] As seen in FIG. 1A, pump 290 may pump a flow of ambient air through microbial membrane filter 292 through inlet 318. As seen in FIG. 2A, inside container 316, air flow 334 may combine with fluid pumped from sorbent bed 294 into lower fluid channel 330. Fluid may enter lower fluid channel 330 anywhere along the path of lower fluid channel 330. The addition of air flow into lower fluid channel 330 may cause fluid and gas from the sorbent cartridge to follow a path defined by lower fluid channel 330 that leads to port 332, which fluidly connects lower fluid channel 330 and upper fluid channel 340.

[0034] Each of the lower fluid channel 330 and the upper fluid channel can be an elongated channel. Each fluid channel can be at least about 6 inches, alternatively at least about 7 inches, alternatively at least about 8 inches, alternatively at least about 9 inches, alternatively at least about 10 inches long, alternatively about 6 inches to about 12 inches in length, alternatively about 7 inches to about 11 inches, alternatively about 8 inches to about 11 inches, alternatively about 6 inches to about 25 inches, alternatively about 6 inches to about 20 inches, alternatively about 6 inches to about 15 inches in length. Each of the lower fluid channel 330 and the upper fluid channel can be in a spiral pattern (see, e.g., FIGS. 2A and 2B), a switchback pattern, random, or other suitable arrangement that is a first of a length of the fluid path within the container 316. In embodiments in which the pattern of the lower fluid channel 330 and the upper fluid channel 340 is a spiral, each spiral can be either clockwise or counterclockwise from the center (e.g., as viewed from the top of the degassing unit 300). In some embodiments, each spiral can be in the same clockwise or counterclockwise direction, or each spiral can be in a different direction, such as one clockwise and the other counterclockwise.

[0035] 1B, 3B, and 3C, surface 338 separates lower fluid channel 330 and upper fluid channel 340 such that lower 330 and upper 340 fluid channels are in fluid communication only through port 332. Surface 338 may have a dome (see, e.g., FIGS. 3B and 3C) or cone shape, whereby port 332 is at a height or elevation above an outer edge of lower fluid channel 330. In some embodiments, the port may be at least about 0.125 inches, alternatively at least about 0.25 inches, alternatively at least about 0.4 inches, alternatively at least about 0.5 inches, alternatively between about 0.125 inches and about 0.8 inches, alternatively between about 0.125 inches and about 0.7 inches, alternatively between about 0.125 inches and about 0.6 inches, alternatively between about 0.125 inches and about 0.5 inches higher than the outer edge of lower fluid channel 330. In embodiments in which the surface has a dome shape, the port 332 may be located at or near the center of the dome. Thus, the surface 338 defining the top of the lower fluid channel 330 may have a concave surface, and the surface 338 defining the bottom of the upper fluid channel 340 may have a convex surface. Alternatively, the surface 338 may be flat, i.e., horizontal (not shown). In embodiments in which the lower and upper fluid channels 330, 340 each have a spiral shape or pattern, the ports 332 connecting the channels may be located at the center of each of the spirals, and the air inlet port 318 and liquid outlet port 320 may be located at or near the outer edges of the lower and upper fluid channels 330, 340, respectively.

[0036] 1A, 1B, and 2A, an air flow can be pumped into the lower fluid channel 330 through the air inlet 318, and the air flow 334 can mix in the lower fluid channel 330 with a fluid, e.g., regenerated dialysate, being pumped upward from the sorbent bed 294. The fluid can enter the lower fluid channel 330 anywhere along the path of the lower fluid channel 330. The flow rate of the ambient air flow into the degassing unit 300 can be from about 100 mL / min to about 600 mL / min, alternatively, from about 200 mL / min to about 600 mL / min, alternatively, from about 200 mL / min to about 500 mL / min, alternatively, from about 200 mL / min to about 400 mL / min. The flow rates of fluids and gases from adsorbent bed 294 can be from about 100 mL / min to about 600 mL / min, alternatively from about 200 mL / min to about 600 mL / min, alternatively from about 200 mL / min to about 500 mL / min, alternatively from about 200 mL / min to about 400 mL / min. In some embodiments, the flow rates of ambient air and the flow rates of fluids and gases from adsorbent bed 294 are substantially the same. Alternatively, the difference between the flow rate of ambient air and the flow rate of fluids can be from about 50 mL / min to about 100 mL / min, alternatively from about 50 mL / min to about 200 mL / min, alternatively from about 100 mL / min to about 300 mL / min, alternatively from about 100 mL / min to about 400 mL / min, alternatively from about 200 mL / min to about 400 mL / min, alternatively from about 300 mL / min to about 500 mL / min.

[0037] As seen in FIG. 2A, the path of the airflow 334 may urge the fluid to flow through and along the path defined by the lower fluid channel 330 until the fluid reaches the port 332 and flows through it into the upper fluid channel. The long path defined by the lower fluid channel 330 allows for mixing of the airflow 334 from the ambient air with the fluid containing CO2. As the fluid flows through the lower fluid channel 330, the partial pressure of CO2 within the fluid (e.g., regenerated dialysate) may equilibrate with the ambient air, thereby lowering the total amount of dissolved CO2. As explained above with reference to Henry's Law, lowering the partial pressure of CO2 with respect to the fluid lowers the total amount of dissolved CO2.

[0038] After exiting the lower fluid channel 330 through port 332 and entering the upper fluid channel 340 through port 332, the fluid flows through a path 336 defined by the upper fluid channel 340 until it reaches a liquid outlet port 320, which may be located at or near the outer edge of the upper fluid channel 340. The flow rate of the fluid at or near the center of the upper fluid channel 340 may be higher than the flow rate of the fluid at or near the outer edge of the upper fluid channel 340 due to the higher pressure near the center of the upper fluid channel 340. The long path defined by the upper fluid channel 340 allows at least a portion of the gas contained in the fluid to dissipate out of the fluid into the atmosphere as the fluid follows the path 336 through the upper fluid channel 340. The long length of the upper fluid channel 340 may allow the gas and liquid time to separate. As the gas-containing fluid moves around the upper fluid channel (e.g., the spiral channel path 336 shown in FIG. 2B), the gas-containing fluid may experience a centripetal force, which is greater in the liquid due to the greater mass of the gas compared to the mass of the liquid. This greater force required to change the direction of the liquid may cause the liquid to be forced outward of the upper fluid channel 340 (e.g., the outer wall of the spiral depicted in FIG. 2B). This may help collect small gas bubbles at the center of the upper fluid channel 340 or at the inner wall of the upper fluid channel 340, thereby allowing the small gas bubbles to rise up to the hydrophobic degassing membrane 328, where larger bubbles are less likely to remain mixed in the liquid flow or to stick to the surface. Thus, the centripetal force may help separate the gas (e.g., CO2) from the liquid. As the gas separates from the liquid in the upper fluid channel 340, the gas may pass through a hydrophobic membrane 328 positioned above the upper fluid channel 340, while the liquid may exit through a liquid outlet 320 at the bottom of the channel.

[0039] A hydrophobic degassing membrane 328 may be disposed above the upper fluid channel 340, and the hydrophobic degassing membrane 328 may contact the fluid flowing through the upper fluid channel 340. Because the membrane 328 is hydrophobic, generally, fluid will not pass through the membrane 328 (i.e., it is impermeable to liquids), but will allow gas to pass through the membrane. The fluid in contact with the hydrophobic membrane 328 may be under a slight amount of back pressure (e.g., <5 psi) that allows CO2 and air bubbles to leave the fluid stream. The hydrophobic degassing membrane 328 may have a pore size of about 0.005 μm to about 1.5 μm, alternatively about 0.005 μm to about 1.3 μm, alternatively about 0.005 μm to about 1.0 μm, alternatively about 0.006 μm to about 1.0 μm.

[0040] As seen in FIG. 3A, a cover 314 over the container 316 may be added to close the system and reduce environmental contaminants from entering the fluid. The cover 314 may include an opening 342 to allow gas (e.g., CO2 from the fluid) to escape into the atmosphere. As seen in FIGS. 1B, 3B, and 3C, the cover 314 may also include additional structure 350 to help keep the hydrophobic membrane 328 substantially flat. Without the additional structure 350, the hydrophobic membrane 328 may form a curved concave surface with a higher point in the center of the hydrophobic membrane 328 compared to the outer edge of the hydrophobic membrane 328 due to pressure within the container 316. When the hydrophobic membrane 328 is no longer substantially flat, a portion of the hydrophobic membrane 328 may not contact the liquid in the upper fluid channel 340. The additional structures 350 may be in any shape that helps to keep the hydrophobic membrane 328 substantially flat or planar in addition to maintaining a gap above the membrane to allow gas to escape through the openings 342. The additional structures 350 may depend on the pattern of the upper fluid channel 340, as the additional structures 350 may complement the pattern of the upper fluid channel 340. For example, in embodiments where the upper fluid channel 340 is in a spiral configuration, the additional structures 350 may also be in a complementary spiral configuration, where at least a portion of the walls defining the spiral in the additional structures 350 may be positioned between the walls defining the spiral configuration of the upper fluid channel 340, as seen in FIGS.

[0041] Various aspects of the subject matter are described herein below with a review and / or complement of the previously described embodiments, with emphasis on the interrelationships and interchangeability of the following embodiments. In other words, emphasis is placed on the fact that each feature of the embodiments can be combined with any and all other features, unless explicitly stated otherwise or logically unlikely to be true. The embodiments described herein are described again and elaborated in the following paragraphs without explicit reference to figures.

[0042] In many embodiments, a degassing module is described that may include an air inlet port, a fluid outlet port, first and second channels disposed within an internal chamber, each configured to direct a flow of a fluid, the first channel in communication with the air inlet port and the second channel in communication with the fluid outlet port, a port connecting the first and second channels, and a hydrophobic membrane positioned above the second channel.

[0043] In some embodiments, the degassing module further includes a cover with a gas exit port, the cover being positioned above the hydrophobic membrane.

[0044] In some embodiments, each of the first and second channels has a helical configuration.

[0045] In some embodiments, the port connecting the first and second channels is located at or near the center of the first channel and at or near the center of the second channel.

[0046] In some embodiments, the first channel has a helical configuration with a center and an outer periphery of the helical configuration, and the air inlet port is located at the outer periphery.

[0047] In some embodiments, the degassing module further includes a substrate separating the first and second channels, the substrate comprising a port connecting the first and second channels, hi some embodiments, the substrate comprises a dome shape, and the port is disposed approximately near a center of the dome shape.

[0048] In some embodiments, the second channel is disposed above the first channel.

[0049] In many embodiments, a system for dialysis is described. The system may include a sorbent regeneration cartridge comprising urease and a metal phosphate, a degassing module comprising an air inlet port, a fluid outlet port, first and second channels disposed within an internal chamber, each of the first and second channels configured to direct a flow of fluid, the first channel in communication with the air inlet port and the second channel in communication with the fluid outlet port, a port connecting the first and second channels, and a hydrophobic membrane positioned above the second channel.

[0050] In some embodiments, the degassing module further includes a cover with a gas exit port, the cover being positioned above the hydrophobic membrane.

[0051] In some embodiments, each of the first and second channels has a helical configuration.

[0052] In some embodiments, the port connecting the first and second channels is located at or near the center of the first channel and at or near the center of the second channel.

[0053] In some embodiments, the first channel has a helical configuration with a center and an outer periphery of the helical configuration, and the air inlet port is located at the outer periphery.

[0054] In some embodiments, the degassing module further includes a substrate separating the first and second channels, the substrate comprising a port connecting the first and second channels, hi some embodiments, the substrate comprises a dome shape, and the port is disposed approximately near a center of the dome shape.

[0055] In some embodiments, the second channel is disposed above the first channel.

[0056] In some embodiments, the metal phosphate comprises zirconium phosphate.

[0057] In some embodiments, the metal phosphate comprises at least one of iron (III) phosphate, titanium (IV) phosphate, cerium (IV) phosphate, and combinations thereof.

[0058] In some embodiments, the metal phosphate comprises a mixture of at least two metal phosphates.

[0059] In some embodiments, the metal phosphate comprises a mixture of zirconium phosphate and titanium phosphate.

[0060] In many embodiments, a method of degassing a fluid comprising CO2 is described. The method may include pumping a flow of air into the fluid stream into a first channel to form an aerated fluid stream, the aerated fluid stream flows through the first channel, exits a port, and flows through a second channel, and CO2 bubbles are released from the aerated fluid in the second channel.

[0061] In some embodiments, the air flow has a flow rate of about 300 mL / min to about 500 mL / min.

[0062] In some embodiments, the method further includes pumping the fluid stream through the first channel, the fluid stream being pumped at a rate between about 300 mL / min and about 500 mL / min.

[0063] In some embodiments, the rate of flow of the fluid stream is approximately the same as the rate of flow of the air into the first channel.

[0064] In some embodiments, the CO2 bubbles are released through a hydrophobic membrane. In some embodiments, the hydrophobic membrane is disposed above the second channel.

[0065] In some embodiments, the first channel has a helical shape. In some embodiments, the second channel has a helical shape. In some embodiments, the port is disposed near a center of the helical shape of the first channel and near a center of the helical shape of the second channel.

[0066] In some embodiments, the second channel is positioned above the first channel.

[0067] It should be noted that all features, elements, components, functions, and steps described with respect to any embodiment provided herein are intended to be freely combinable and substituted with those from any other embodiment. If a feature, element, component, function, or step is described with respect to only one embodiment, it should be understood that the feature, element, component, function, or step may be used with all other embodiments described herein unless expressly stated otherwise. This paragraph therefore serves as a preamble and descriptive aid for the introduction of claims that combine features, elements, components, functions, and steps from different embodiments or substitute features, elements, components, functions, and steps from one embodiment with another, whenever possible, even if the preceding description does not expressly state that such combinations or substitutions are possible in a particular case. In particular, it should be expressly recognized that expressing a list of all possible combinations and substitutions would be unduly burdensome, given that the permissibility of all such combinations and substitutions would be readily recognized by those skilled in the art.

[0068] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0069] The embodiments are susceptible to various modifications and alternative forms, specific examples of which are shown in the drawings and described in detail herein. However, it should be understood that these embodiments are not limited to the particular forms disclosed, but on the contrary, these embodiments should cover all modifications, equivalents, and alternatives falling within the spirit of the disclosure. Furthermore, any feature, function, step, or element of the embodiments may be recited in or added to the claims, as well as negative limitations that define the scope of the claimed invention by features, functions, steps, or elements not within their scope.

Claims

1. A degassing module, comprising: An air inlet port; A fluid outlet port; first and second channels disposed within the interior chamber, each of the first and second channels configured to direct a flow of a fluid, the first channel in communication with the air inlet port and the second channel in communication with the fluid outlet port; a port connecting the first and second channels; a hydrophobic membrane positioned over the second channel; and The degassing module comprises:

2. The module of claim 1 , further comprising a cover with a gas exit port, said cover positioned above said hydrophobic membrane.

3. The module of claim 1 , wherein the first channel and the second channel each have a helical configuration.

4. 2. The module of claim 1, wherein the ports connecting the first and second channels are located at or near a center of the first channel and at or near a center of the second channel.

5. The module of claim 1 , wherein the first channel has a spiral configuration having a center and an outer edge of the spiral configuration, and the air inlet port is disposed at the outer edge.

6. 2. The module of claim 1, further comprising a substrate separating the first and second channels, the substrate comprising the port connecting the first and second channels.

7. The module of claim 6 , wherein the substrate comprises a dome shape and the port is disposed approximately near the center of the dome shape.

8. The module of claim 1 , wherein the second channel is disposed above the first channel.

9. 1. A system for dialysis, comprising: a sorbent regeneration cartridge comprising urease and a metal phosphate; Degassing module and Equipped with The degassing module comprises: An air inlet port; A fluid outlet port; first and second channels disposed within the interior chamber, each of the first and second channels configured to direct a flow of a fluid, the first channel in communication with the air inlet port and the second channel in communication with the fluid outlet port; a port connecting the first and second channels; a hydrophobic membrane positioned over the second channel; and The system comprises:

10. The system of claim 9 , wherein the degassing module further comprises a cover with a gas exit port, the cover being positioned above the hydrophobic membrane.

11. The system of claim 9 , wherein the first channel and the second channel each have a helical configuration.

12. 10. The system of claim 9, wherein the ports connecting the first and second channels are located at or near a center of the first channel and at or near a center of the second channel.

13. 10. The system of claim 9, wherein the first channel has a spiral configuration having a center and an outer edge of the spiral configuration, and the air inlet port is disposed at the outer edge.

14. 10. The system of claim 9, wherein the degassing module further comprises a substrate separating the first and second channels, the substrate comprising the port connecting the first and second channels.

15. The system of claim 14 , wherein the substrate comprises a dome shape and the port is disposed approximately near the center of the dome shape.

16. The system of claim 9 , wherein the second channel is disposed above the first channel.

17. The system of claim 9 , wherein the metal phosphate is zirconium phosphate.

18. 10. The system of claim 9, wherein the metal phosphate is selected from the group consisting of iron (III) phosphate, titanium (IV) phosphate, cerium (IV) phosphate, and combinations thereof.

19. The system of claim 9 , wherein the metal phosphate comprises a mixture of at least two metal phosphates.

20. 10. The system of claim 9, wherein the metal phosphate comprises a mixture of zirconium phosphate and titanium phosphate.

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