Patent Publication Number: US-2021170457-A1

Title: Methods and systems for disposing alkali metal patches

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The application claims the benefit of U.S. Provisional Patent Application No. 62/946,124, filed Dec. 10, 2019, which is hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The technology described herein generally relates to methods and devices to dispose alkali metal patches after use by a patient under a therapeutic procedure. 
     BACKGROUND 
     Disposable medical devices for use by patients may include amounts of highly reactive materials, compounds, or elements. The disposal of such devices after use poses a hazardous challenge for the patients, for the medical personnel, and for the facility storing the disposal materials. In some configurations, it may be desirable to neutralize the disposable medical device completely, prior to, or in conjunction with, disposing of it. In the case of medical devices containing alkali materials, effective disposal methodologies that can be applied with simplicity, rapidly, and securely are lacking or non-existent. 
     SUMMARY 
     In a first embodiment, a method for disposing of a device having an alkali metal includes placing into a container a device including a layer portion having at least an alkali metal, an oxide of the alkali metal, a hydroxide of the alkali metal, or any combination thereof. The method also includes controllably exposing the layer portion on the device to a reactant for the alkali metal or a solubilizer of the alkali metal and allowing the alkali metal to react with the reactant or to dissolve in the solubilizer to render the alkali metal substantially non-reactive. The method also includes optionally disposing of the device, the container, or both. 
     In a second embodiment, a kit is disclosed that includes a device including a layer of an alkali metal and a disposal container. The disposal container has a cavity configured to receive the device and an opening configured to receive the device into the cavity, the opening closable or capable of being closed. The disposal container also includes one or more of: (i) a solvent that dissolves the alkali metal, (ii) a means for the egress of hydrogen or a scavenger of hydrogen, and (iii) a source of reactant or a mechanism to receive a reactant from an external source. In one embodiment, the reactant is water. 
     In a third embodiment, a method is disclosed that includes sealing, in a disposal container, a device including a layer of an alkali metal and an oxide or a hydroxide of the alkali metal. The disposal container includes a closeable opening and a semi-permeable membrane. The method also includes allowing a water vapor molecule to contact the layer and controllably oxidizing the alkali metal to form an alkali metal oxide or hydroxide and to generate a hydrogen molecule. The method also includes allowing the hydrogen molecule to egress the disposal container. 
     In yet another embodiment, a container includes an enclosure forming a cavity and configured to receive a device including an alkali metal layer in the cavity and a medium configured to allow contact of a water molecule or a reactant with the alkali metal at a pre-selected rate or in a controlled manner. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a kit for disposing of a used patch, according to some embodiments. 
         FIG. 2  illustrates a kit for disposing of a used patch that is put in contact with a coated mesh, according to some embodiments. 
         FIG. 3  illustrates a kit for disposing of a used patch including a first compartment and a second compartment, according to some embodiments. 
         FIG. 4  illustrates a kit for disposing of a used patch including a first compartment, a second compartment, and a third compartment, according to some embodiments. 
         FIG. 5  illustrates a container for disposing of a used patch including a cylindrical compartment, according to some embodiments. 
         FIG. 6  illustrates a container for disposing of multiple used patches, according to some embodiments. 
         FIG. 7  illustrates a device for disposing of a used patch, according to some embodiments. 
         FIG. 8  is a flow chart illustrating steps in a method for disposing of a used patch, according to some embodiments. 
         FIG. 9  is a flow chart illustrating steps in a method for disposing of a used patch, according to some embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Devices including an alkali metal (e.g., lithium, sodium, potassium, rubidium, cesium, francium, or any combination of the above) enable an approach for effective treatment of certain skin conditions, such as hyperhidrosis (the profusion of sweat) or other medical or aesthetic dermatological conditions. The alkali metal devices can be applied to a human body surface, such as skin, for such medical therapy. In some embodiments, the alkali metal device may include a pen-like device, or stylus for wound closure. The device has a core made of a thin, elongated column of alkali metal (e.g., a mechanical pencil with a′/4 inch diameter led made from the alkali metal). The user applies the pen over a wound, tracing a thin layer of alkali metal over the tissue, for healing. The slow reaction of the alkali metal with the skin moisture and ambient air creates a gentle amount of heat that promotes tissue recovery. 
     The devices can also be used to substantially sterilize or render substantially aseptic a surface—a human skin surface or any other surface, such as a surgical instrument, a laboratory bench top surface, or a petri dish. Approaches for safe and easy disposal of the devices are needed, whether the device is used in a controlled environment of a healthcare facility (e.g., hospital, clinic, doctor&#39;s office), in a laboratory, or in a home setting. 
     Alkali metals (e.g., sodium, potassium lithium, rubidium, cesium, or francium) are highly reactive. The reaction is typically vigorous and exothermic, sometimes melting the metal, sometimes igniting the evolved hydrogen, and sometimes inducing a Coulomb explosion. Embodiments as disclosed herein include methods and systems to safely neutralize and dispose of alkali metal-based skin patches, pens, and other related therapeutic devices by the end user (e.g., in a hospital, doctor office, clinic, or eventually patient household settings). Methods and devices disclosed herein allow the alkali metal or alkali metal oxide or hydroxide to chemically react in a controlled manner, avoiding the excess temperatures or reaction conditions that may melt the alkali metal or ignite evolved hydrogen (H 2 ) or related flammable gasses or materials. Some embodiments include commercial/residential waste streams, e.g., city drainage or trash disposal means. 
     Accordingly, disclosed herein are methods and devices to neutralize, render harmless, deactivate, and/or consume an alkali metal in a device including an alkali metal layer. When the alkali metal reacts with water, e.g., during use of the device when the alkali metal layer contacts sweat or another source of water, energy (e.g., heat) is generated from the exothermic reaction between water and the alkali metal. In some embodiments, the alkali metal may include an alloy of an alkali metal, or any compound having less than 100% alkali metal in it. The energy is transferred to the treatment surface, such as a skin or body surface of a human, to provide a clinical benefit. In some embodiments, the device, also referred to herein as a patch, is configured for a single-use and to be disposable, and the single-use may leave a portion of the alkali metal unreacted—e.g., a portion of the alkali metal remains capable of reaction with water. Accordingly, it is desirable to have a simple, safe way to react the unused or unreacted portion of alkali metal, to render it safe so that it may be disposed of with conventional methods (e.g., mixed into a solution that can be drained or placed in a garbage container). 
     A reaction of an alkali metal compound (e.g., sodium, Na; potassium, K) with water (e.g., the “reactant” or “solubilizer”) may be described with the following chemical equation: 
     
       
         
           
             
               
                 
                   
                     
                       Na 
                       
                          
                         
                           Alkali 
                            
                           
                               
                           
                            
                           Metal 
                         
                       
                     
                     + 
                     
                       
                         
                           H 
                           2 
                         
                          
                         O 
                       
                       
                          
                         Reactant 
                       
                     
                   
                   → 
                   
                     
                       
                         Na 
                         
                           ( 
                           
                             a 
                              
                             q 
                           
                           ) 
                         
                         + 
                       
                       + 
                       
                         OH 
                         
                           ( 
                           
                             a 
                              
                             q 
                           
                           ) 
                         
                         - 
                       
                       + 
                       
                         
                           1 
                           2 
                         
                         · 
                         
                           H 
                           
                             2 
                              
                             
                               ( 
                               g 
                               ) 
                             
                           
                         
                       
                       + 
                       energy 
                     
                     
                        
                       Product 
                     
                   
                 
               
               
                 
                   ( 
                   1 
                   ) 
                 
               
             
           
         
       
     
     The reaction in Eq. 1, where Na is used as an example for illustrative purposes only, is highly exothermic, and may in fact produce a harmful, explosive shock. To avoid the explosive shock, it is important to limit the rate of the reaction. Moreover, a sudden rise in temperature from the heat may further lead to ignition of the hydrogen, H 2 , especially when a sizeable amount of hydrogen has accumulated after a certain amount of time. For instance, when sodium metal contacts liquid water, a large quantity of heat is generated along with hydrogen. The heat may cause the alkali metal to melt, generating liquid metallic droplets that may detach from the alkali metal that composes the device, further worsening the hazard. Methods and devices as disclosed herein avoid the above undesirable effects, providing a user-friendly disposal means. 
     Another challenge is the removal of the residual hydrogen, steam, and related gasses. For example, in some embodiments, a used patch may include an alkali layer with dimensions 100 mm×100 mm×0.1 mm (1000 mm 3 =1 mL=1 cm 3  of Na). With a density of ρ Na =0.97 g/cm 3 , and a molar weight (MW=23 g/mol), this results in 0.97/23=0.0422 mol of Na in the used patch. According to the stoichiometry of Eq. 1, this corresponds to: 0.0422/2 mol (of H 2 )÷22.4 L/mol (molar volume of H 2  at STP)=473 mL H 2  per Patch. That is, in some embodiments, a single-used patch neutralization produces almost half a liter of highly flammable hydrogen gas. Accordingly, embodiments such as those disclosed herein may include: hydrogen scavenging materials, solutions, and/or structures, purging inert gases, valves, and membranes to trap or allow the egress of hydrogen and related gasses that are generated during the reaction. 
     Embodiments as disclosed herein provide various solutions to convert the alkali metal residue in a used patch into another, non-pyrophoric substance, such as a metal hydroxide, a metal alkoxide, or a salt (e.g., an alkali-halide such as NaCl, and the like). 
     Accordingly, embodiments include a disposal means having containers with one or more compartments and are configured to limit the chemical reaction (cf. Eq. 1) so as to avoid any possible explosive conditions. Disposal kits as disclosed herein control the rate of the reaction to neutralize the alkali metal, and completely consume the residual alkali metal in the patch to yield a non-pyrophoric substance that can be discarded in standard waste streams (e.g., garbage containers, drains, or similar means). In some embodiments, a disposal kit may contain and manage the heat generated by the reaction such that it is safe for the user. For example, in some embodiments, the exterior portion of a container as disclosed herein is safely maintained below 50° C. 
     Disposal kits as disclosed herein may include vents, absorbing materials, gels, solutions, or other controls to manage products including gas(es), e.g., hydrogen, that are involved in the reaction described in Eq. 1 or equivalents. 
       FIG. 1  illustrates a disposal kit  100  for disposing of a used patch  101 , according to some embodiments. Used patch  101  is generically a device including a layer of an alkali metal  103 . In some embodiments, disposal kit  100  may be configured as a single-use disposal unit (e.g., the user disposes of at least a portion of disposal kit  100  after used patch  101  is neutralized). In some embodiments, disposal kit  100  may be configured to receive and neutralize multiple used patches  101  before being discarded. In yet other embodiments, disposal kit  100  may be configured to receive and neutralize multiple used patches  101  that are removed from disposal kit  100  when, for example, an indicator means signals that it is safe to do so. In such embodiments, the used, neutralized alkali patches  101  may be removed from disposal kit  100  and safely discarded to allow the continued introduction of further used patches  101 . 
     Disposal kit  100  includes a disposal container  105  including a cavity  107  and an opening  109  configured to receive used patch  101  into cavity  107 . In some embodiments, container  105  includes a packaging that is substantially impermeable to water and to air, having a closeable opening  109 . In some embodiments, closeable opening  109  includes a sliding lock (e.g., a Ziploc top) or screw cap to seal the used patch in the disposal container. In some embodiments, disposal container  105  is manufactured at least in part from a water-permeable material. In some embodiments, disposal container  105  may include a polyethylene or polypropylene vial or a poly bag. Further, in some embodiments, disposal container  105  may include at least one or more walls (e.g., a front wall and a rear wall), where the bottom wall is attached to the front and rear walls. In some embodiments, disposal container  105  further includes two side walls, where each side wall is connected to the front wall, the rear wall, and to the bottom wall, wherein at least one wall is flexible. In some embodiments, at least one of the walls is circular or curved, and disposal container  105  includes an annular or a circular cavity. In some embodiments, at least one of the walls in the container may include a metal, a metal foil (e.g., stainless steel, or Mylar), or a metal-sputtered plastic film. 
     In one embodiment, disposal container  105  may have a venting cap or valve  112  to allow a hydrogen (or any other excess gas) egress from and allows water into, disposal container  105 . 
     In some embodiments, disposal container  105  includes a reactant  115  that chemically interacts with alkali metal  103  in used patch  101  to neutralize it. Reactant  115  may include a solvent that is miscible with water and that dissolves alkali metal  103 . The solvent may include an alcohol or a glycol, wherein the alcohol is selected from ethanol, isopropanol, t-butanol, stearyl alcohol, and tris(trimethylsilyl)methanol, and the glycol includes propylene glycol. In some embodiments, the reactant may include a few milliliters of substantially anhydrous R—OH (˜99%) solution, where R is an unspecified chemical group. For example, in some embodiments, reactant  115  may include ethanol, isopropanol, t-butanol, or heavier, unusual or sterically hindered alcohols having a more predictable and slow reactivity. In some embodiments, reactant  115  may include a low viscosity or gelled solution to react with alkali metal  103 . In some embodiments, the water or water solution is contained on or in a sponge, a porous body, or an absorbent polymer substrate. In some embodiments, the absorbent polymer substrate may be a hydrogel including a cross-linked hydrophilic polymer. In some embodiments, reactant  115  may include a triglyceride, an anhydrous foam, or a compound with a counter ion that produces upon reacting with sodium or related metals or alloys a compound selected from sodium alginate, sodium difluoride, sodium fluorosilicate, sodium metaborate, sodium paraperiodate, sodium stearate, sodium zirconium glycolate, and sodium perrhenate (NaReO 4 ) in anhydrous ethanol. The addition of sodium or other alkali metals will produce nonahydridorhenate. These are well-behaved reactions that yield inert salts. In some embodiments, the rhenium (Rh) compound may be replaced with more affordable substances such as with technetium (Tc) or manganese (Mn). 
     Further, in some embodiments, disposal kit  100  may include a mechanism to receive water from an external source. In some embodiments, the reactant may be a compound with a counter ion that produces upon reacting with sodium a compound selected from sodium alginate (NaC 6 H 7 O 6 ), potassium difluoride (KHF 2 ), sodium difluoride (NaHF 2 ), sodium fluorosilicate (Na 2 SiF 6 ), sodium metaborate (NaBO 2 ), sodium paraperiodate (Na 3 H 2 IO 6 ), sodium stearate (NaOOCC 17 H 35 ), and sodium zirconium glycolate (NaZrH 3 (H 2 COCOO) 3 ). 
     In some embodiments, the mechanism to receive water from an external source is a water or moisture-permeable polymer membrane. In addition to water or a solution of water and salt, solutions that may be used to limit the rate of the chemical reaction (Eq. 1) may include: propylene glycol (PG), alcohol, or high molar NaOH(aq) such as 10M NaOH, which slowly reacts with the sodium in a controlled manner. 
     Additionally, in some embodiments, reactant  115  may include carbon dioxide to form a carbonate of the alkali metal. The CO 2  may be in gaseous form or at least one compartment could be filled with a substance that releases carbon dioxide. Additionally, carbon tetrachloride and dichloromethane react vigorously with sodium and could be used as reactant  115  to expend the used sodium. 
     In some embodiments, it may be beneficial to neutralize the products following the alkali metal reactions (cf. Eq. 1). Highly basic alkali hydroxides (e.g., NaOH, cf. Eq. 1) are caustic and/or corrosive, and may be a hazardous challenge to dispose of. Accordingly, some embodiments may include buffers, acids, or similar compounds in a solution of reactant  115 , to neutralize or control the reaction products (e.g., right hand side of Eq. 1). 
     One or more walls of cavity  107  may include a membrane that is selectively permeable to hydrogen. Such semi-permeable membrane can be polymeric membranes, porous membranes, dense metal membranes, or ion-conductive membranes. Exemplary porous membranes include ceramic, carbon, and metallic membranes. Exemplary polymer membranes include: aromatic polyimides, polysulfone, cellulose acetate, polyethylene, and tetrabromopolycarbonate. Exemplary dense metal membranes include palladium and palladium-based alloy membranes. The hydrogen permeable membrane can also be a hybrid membrane of nanoparticles dispersed in a polymer matrix, such as those described, for example, in Pulyalina A., et al., Polymers, 10(8): 828 (2018). Some embodiments allow hydrogen to escape while retaining water vapor or steam. In some embodiments, the alkali patch may be partially or totally immersed in the reactant (e.g., a PG solution). Some embodiments control the environment of disposal container  105  so as to provide a high humidity level. For the latter, disposal container  105  may include a membrane that vents hydrogen at a higher rate than water vapor or steam that may be desirable. 
     In one embodiment, water vapor enters cavity  107  of a pouch and the reaction with alkali metal  103  proceeds (cf. Eq. 1). Hydrogen exits cavity  107  through the membrane or material that is hydrogen-permeable, and the alkali metal then oxidizes, leaving behind a high molar hydroxide hydrate, a crust, or layer of alkali hydroxide (e.g., NaOH cf. Eq. 1) on the used patch, which is safely sealed in the first cavity. In another embodiment, the hydrogen permeable membrane has a permeation or diffusion rate for hydrogen that is at least about 10%, 20%, 25%, 30%, 35%, 40%, 50%, 60%, 75%, or higher than the permeation rate for water vapor or steam. 
     In some embodiments, at least the first cavity in the container may include a wall wherein at least a portion of the wall includes a hydrogen-permeable membrane or material (e.g., a synthetic polymer such as those mentioned above, and similar). In some embodiments, the semi-permeable membrane may also be permeable to water vapor or steam. The semi-permeable membrane may be disposed on a bottom wall of disposal container  105 . The hydrogen released by the interaction between the reactant and the alkali metal may then egress freely from disposal container  105  through the hydrogen-permeable membrane and be released into the atmosphere. Disposal container  105  including used patch  101  may then be safely discarded using regular procedures. In some embodiments, disposal container  105  also includes a source of reactant (e.g., water or other solvent) or a mechanism to receive a reactant from an external source (e.g., the reaction products on the left-hand side of Eq. 1). In one embodiment, used patch  101  is exposed to water or an aqueous solution in a manner that limits the availability of water for reaction with alkali metal  103  or alloy thereof, thus avoiding an explosive regime. In some embodiments, the reactant may include a membrane with a pre-selected diffusion gradient that slowly passes water (in liquid or vapor form) across to cavity  107  that includes used patch  101 . In some embodiments, reactant  115  includes an aqueous solution, such as a propylene glycol (PG)+water, salt+water, or alcohol+water. In some embodiments, the reactant  115  includes a sponge that entrains water and slowly allows it to ingress into cavity  107  at a limited rate to provide for a controlled reaction. 
     In some embodiments, reactant  115  may include water or a water solution embedded in a sintered metal, a porous polymer, a porous plastic, or an absorbent polymer substrate (e.g., a hydrogel including a cross-linked hydrophilic synthetic polymer). More specifically, the sintered metal forms a rate-limiting interface between reactant  115  and alkali metal  103  in used patch  101 . Further, because the metal has a relatively high thermal mass, the sintered metal could control the temperature of the reacting alkali metal  103  below its melting point and below the auto-ignition temperature of hydrogen. The sintered metal or plastic material or combinations thereof may provide a torturous/porous path to limit the rate of water ingress into cavity  107  that contains used patch  101 . In some embodiments, reactant  115  may include beads, a film or sheet of any combination of hydrogel, absorbent or super-absorbent polymer, polyvinyl alcohol (PVA), silicone, or any suitable substrate that contains water or an aqueous solution. 
     In some embodiments, reactant  115  may include a solution of propylene glycol (PG). Propylene glycol has the benefit of being miscible with water. It is also non-flammable, and safe to use. In some embodiments, the reactant may include a 100% PG solution, or any other ratio of PG/H 2 O so as to effectively dissolve the patch. For embodiments in which used patch  101  has an alkali metal  103  with a thin foil sheet (e.g., about ˜0.005 in of metal or alloy, or less), it may take approximately 30 minutes to completely dissolve the alkali when immersed in a 100% PG solution. Dissolution of alkali metal  103  in used patch  101  occurs faster when the amount of water in the aqueous PG solution increases. In some embodiments, it may be desirable to maintain the level of water in the aqueous PG solution to less than approximately 10% to avoid generating too much heat and the formation of small metallic beads due to melting of alkali metal  103 . When beads of alkali metal  103  float to the surface of the solution (e.g., a solution including reactant  115 ), they continued to react with the solution, air, and water vapor, and in some cases may undesirably ignite the evolved hydrogen. 
     In some embodiments, the concentration of the PG/water solution may be adjusted (e.g., “tuned”) to obtain a desirable reaction rate. For example, in some embodiments, the concentration of the PG/water solution can be tuned such that the rate of formation of hydrogen is no faster than the rate at which the hydrogen egresses from the container. Hydrogen is a very small molecule and is therefore difficult to contain. Standard containers, such as a polyethylene bag with a slidable seal (e.g., ZIPLOC®) or a sealable flap, may successfully contain used patch  101  and the solvent, and allow the hydrogen to pass through (or membranes, or Tyvek bags can be used as described above). However, when the reaction is allowed to proceed too quickly, hydrogen may form at a rate that exceeds the egress rate from the container. Accordingly, in some embodiments, a careful selection of the ratio of PG and water in solution may slow hydrogen production to a rate that it is matched by the egress rate from disposal container  105 . 
     In some embodiments, reactant  115 , or at least a portion of disposal kit  100  may include a color changing material that indicates when the reaction with alkali metal  103  is complete. More generally, reactant  115  or a portion of disposal kit  100  may include a material that changes physically in a perceptible way when the reaction is complete. The physical change could be triggered by heat, by pH of a solution or the reaction products contained therein, and the like. The color change could indicate to a user when the reaction is complete and when it is safe to dispose of disposal kit  100 . 
     In some embodiments, disposal kit  100  may include an excess of a solution having a high thermal capacity or the container may include at least a portion of a wall made of a metal or other material with a high thermal capacity. In some embodiments, disposal kit  100  may include a label or a leaflet  120  (e.g., stamped on the outside of one of the walls, or loosely placed inside the container, or attached through a string). Label or leaflet  120  may include a set of instructions for use. In some embodiments, the instructions may be directly printed on disposal container  105  or on a material that is disposed on an adhesive portion of used patch  101 . 
       FIG. 2  illustrates a kit  200  for disposing of used patch  101  that is put in contact with a mesh  201   a  coated with reactant  115  (e.g., stearyl alcohol), according to some embodiments. Mesh  201   a  may be a mesh, or a non-metallic mesh such as carbon fiber and the like. Mesh  201   a  offers a substrate for reactant  115 , and also a good thermal conductivity that prevents over-heating of used patch  101  due to the neutralizing chemical reaction. In some embodiments, mesh  201   a  may be placed over used patch  101  and both then placed in cavity  107  inside a disposal pouch  205  (cf. disposal container  105 ). Disposal pouch  205  includes valve  112 , reactant  115 , and closeable opening  109 . In some embodiments, mesh  201   a  may be replaced with a membrane  201   b , paper, fiberglass, cloth layer, and the like, impregnated with a salt such as Epsom salt (MgSO 4  7H 2 O), or other water-soluble salts such as CdCl 2  or similar. In some embodiments, mesh  201   a  or membrane  201   b  may include a permeable disposal means such as paper or a membrane to cover the adhesive surrounding the perimeter of alkali metal  103  on used patch  101 . After neutralization of alkali metal  103 , used patch  101  may be quenched with water and discarded. 
     In some embodiments, a suitably doped gel or wax is applied on used patch  101  prior to insertion in disposal pouch  205 . Accordingly, the doped material may include a low concentration halogen (e.g., Cl, F, Br, I, and the like) gradient in a gel or wax. The gradient may be formed upon exposure to room air. Alkali metal  103  would then react with the halogen in a controlled manner to slowly form a salt. Some embodiments may include a coat of an anhydrous foam over used patch  101 ; the foam physically restrains ejected sodium debris, which prevents combustion. 
       FIG. 3  illustrates a kit  300  for disposing of used patch  101  having alkali metal  103 , including a first compartment or cavity  307   a  and a second compartment or cavity  307   b  (hereinafter, collectively referred to as “cavities  307 ”), according to some embodiments. Compartment  307   b  may include reactant  115  (or a solubilizer), separated from the used patch by a wall  315 . A semi-permeable membrane  312  may cover at least a portion of wall  315 . In some embodiments, separating reactant  115  from used patch  101  may reduce the reaction speed, which can safely proceed at a non-explosive rate. 
     In one embodiment, container  305  includes closeable opening  109 . In one embodiment, container  305  may have a one-way valve  311 , such as a duckbill valve, to allow a hydrogen egress from the container (or any other excess gas). One-way valve  311  is configured to open when subjected to a sufficient pressure differential between the inside of compartment  307   a  and the outside atmosphere. In some embodiments, one-way valve  311  is configured to open when pressure inside compartment  307   a  exceeds a threshold pressure. When the reaction product (e.g., the alkali oxide or hydroxide product in the right hand side of Eq. 1) has the physical consistency of a solid or semi-solid form, one-way valve  311  may actuate at a lower pressure differential, or no pressure differential (e.g., a flap valve). In some embodiments, one-way valve  311  may include a check valve or a pressure valve to allow for hydrogen egress from container  105 . 
       FIG. 4  illustrates a kit  400  for disposing of used patch  101  with alkali metal  103 , including a first compartment  407   a , a second compartment  407   b , and a third compartment  407   c  (hereinafter, collectively referred to as “compartments  407 ”), according to some embodiments. In one embodiment, kit  400  includes a container  405  having closeable opening  109 . 
     Third compartment  407   c  may include a hydrogen scavenger material  425 , which reacts with free hydrogen to form a neutral compound. In some embodiments, scavenger material  425  may include a ceramic, a metal, or metal-oxide wire (e.g., platinum-flashed alumina or similar), or any other material having a structure that traps the free hydrogen into a neutral configuration that may be disposed of via regular garbage disposal procedures. In some embodiments, scavenger material  425  may be a few mL of a solution such as dihydrolevoglucosenone (Cyrene), perfluorodecalin, cyclohexane, platinum, or palladium, among others. 
     Compartment  407   b  includes reactant  115  and is separated from compartment  407   c  by a wall  415   b . A semi-permeable membrane  412  separates compartment  407   b  from compartment  407   a , and allows water to flow from the latter to the former. In some embodiments, compartment  407   c  may be separated from compartment  407   a  via a hydrogen-permeable membrane  415   a , or a one-way valve  411 . In some embodiments, one-way valve  411  is activated when the difference in partial pressure of hydrogen between compartment  407   a  and compartment  407   c  exceeds a threshold value. 
       FIG. 5  illustrates a container  500  for disposing of used patch  501  including a cylindrical compartment  505 , according to some embodiments. In some embodiments, cylindrical compartment  505  may include side walls  506   a  and a bottom wall  506   b  (hereinafter, collectively referred to as “outer walls  506 ”) made of a hard plastic or other hard material (e.g., a metal such as stainless steel and the like). In some embodiments, a metal tube forms a cylindrical compartment  505  with an inner annular space  515  of a porous body  507  filled with water or any other reactant  115 . Accordingly, used patch  501  may be placed in annular space  515  so that reactant  115  slowly contacts alkali metal layer  503  on used patch  501  by porous body  507 . Outer walls  506  may act as a thermal mass to constrain the overall temperature of the reaction. In some embodiments, the metal forming outer walls  506  is beneficial to limit the overall temperature increase of the system due to the high heat capacity of the metal. In some embodiments, the metal forms a thermal mass in the shape of a tube, and used patch  501  is placed inside, in the shape of a roll, with alkali metal  503  facing the interior of cylindrical compartment  505 , where reactant  115  is located. More generally, some embodiments include containers  500  made from a material with a heat capacity and mass that effectively limits the rate of the reaction and the overall temperature increase inside container  500 . In some embodiments, cylindrical compartment  505  may include a sintered metal, foil, or solid metal with or without holes or passages for water, or it could be a sufficient quantity of water or an aqueous solution or a non-aqueous solvent. 
     In some embodiments, container  500  may include a temperature control unit  550  to measure the temperature inside of the cylindrical compartment, or in the outer walls  506  of the compartment. The temperature measurement is an indicator of the energy released in the neutralization reaction (cf. Eq. 1) and may include a thermometer or a thermocouple. Accordingly, the temperature value may indicate whether the reaction is occurring too fast, or approaching an explosive or hazardous regime, and whether or not the reaction is complete. 
     In some embodiments, the opening of container  500  may be configured to close by a cap (e.g., a threaded cap) or lid  517 . In some embodiments, container  500  may further include a visual, audible, or electronic indicator or timer  560  that is activated when a sensor indicates that the neutralization reaction (cf. Eq. 1) is complete, or when it is safe to remove used patch  501  from container  500 . In some embodiments, indicator  560  may respond to a temperature sensor, a pH detector, or a photodetector configured to detect the color of a portion of the used patch or the aqueous solution that has made contact with used patch  501 . For example, an optical sensor may be configured to determine an ignition event. More specifically, an optical sensor may be configured to detect a light emission corresponding to at least one wavelength in the emission spectrum of alkali metal  503  (e.g., approximately 589 nm for Na, approximately 794 nm for Rb, approximately 766 nm for K, and the like). 
     One-way valve  511  is configured to open when subjected to a sufficient pressure differential between inner annular space  515  and the outside atmosphere. A semi-permeable membrane  512  may cover at least a portion of porous body  507 . 
       FIG. 6  illustrates a container  600  for disposing of multiple used patches, according to some embodiments. Container  600  includes an interior compartment  605  to receive the used patches through a one-way slot  609  configured as a closeable opening. In some embodiments, one-way slot  609  may include an automatic inlet driver (e.g., a roller). In some embodiments, interior compartment  605  includes an atmosphere that is substantially filled with an inert gas (e.g., argon or nitrogen) to mitigate any risk of an uncontrolled reaction due to atmospheric oxygen or water vapor. In some embodiments, up to a 10/90 air/argon atmosphere may be acceptable, even at temperatures higher than room temperature (e.g., as high as 500° F. for Na). Further, in some embodiments, interior compartment  605  may be continually purged with a flow of an inert gas source  650  to reduce or eliminate the hydrogen resulting from the neutralization reaction of multiple patches. In addition, a one-way valve  611  may be included as described above, to allow the hydrogen gas to egress from compartment  605  while impeding or limiting the ingress of water vapor. 
     In some embodiments, container  600  may be semi-permanent, and receive multiple alkali patches. In some embodiments, container  600  may be wholly or partially replaced once a pre-selected number of alkali patches have been neutralized in its interior. In some embodiments, the interior of container  600  is at least partially filled with a reactant solution  615  (e.g., in addition to the inert gas atmosphere) such as PG, and the like, as discussed above, or any other water evaporator. In some embodiments, the container is occasionally emptied of the used patches that have been neutralized (e.g., 10-20 used patches). In some embodiments, the shape and size of container  600  (e.g., base, neck, top, curvature, geometry, and the like), and the disposition of reactant solution  615  and closeable opening  609 , may be configured to suppress any fire or ignition event in the interior. In that regard, some embodiments may include an alarm, indicator, or timer  660  with associated sensors, to indicate to a user that one or more, or all, of the used patches in the interior have been neutralized. Alarm or indicator  660  may also indicate that a temperature in the interior of container  600  has reached a hazardous level, or that an ignition has occurred or will occur imminently. In some embodiments, compartment  605  may include a scavenger material  425 , as described above. 
       FIG. 7  illustrates a device  700  for disposing of a used patch  101 , according to some embodiments. Device  700  includes a container  705  having a first platen  702   a  and a second platen  702   b  (hereinafter, collectively referred to as “platens  702 ”). One of platens  702  receives used patch  101  (e.g., the bottom platen  702   b ). In some embodiments, used patch  101  could be loaded on platen  702   b  with a paper, or semi-permeable membrane  701  covering the adhesive and trapping alkali metal  103 . In some embodiments, platens  702  are moveably connected. For example, in some embodiments, platens  702  are rotatably coupled through hinges  720  along one of the sides of either platen  702  using a handle  710 . Platens  702  form a closed configuration, trapping used patch  101  in the plane between platens  702 . In some embodiments, at least one of platens  702  includes a region manufactured from a material with a selected thermal conductivity and a selected thermal capacity. In some embodiments, at least one of platens  702  may include a material having a specific heat capacity of at least about the heat capacity of an alkali metal hydroxide at room temperature. Device  700  allows a rapid disposal of used patch  101  while absorbing a controlled amount of heat evolved, as platens  702  may be made of a high thermal capacity material. 
     In some embodiments, one of the platens (e.g., the top platen) includes a substrate  755  having the reactant or solubilizer. In some embodiments, substrate  705  includes a polymer film, a non-woven material, a woven cloth, fiberglass, or paper. Accordingly, the reactant may include MgSO 4 , CdCl 2 , a water solution including any other salt, a water solution, alcohol, a glycol (e.g., PG), or any other solvent as disclosed above. In some embodiments, container  705  may further include valves  711  (e.g., a gas vent, one-way valve, or pressure valve), to release H 2  into the atmosphere. In some embodiments, the dissolution liquid is injected into the cavity via an injection point  730 . 
     In some embodiments, a thermal mass  715  could also be placed on platen  702   b  in contact with the back side of used patch  101  (non-patient contacting side of the used patch) so that alkali metal  103  is not obstructed and can be completely reacted with the reactant on platen  702   a . In some embodiments, device  700  also includes a temperature controller including a temperature sensor, as disclosed above. In some embodiments, temperature controller  750  may be coupled to an alarm or indicator that signals when the temperature has cooled sufficiently to be safe. The temperature controller may monitor the temperature that is passively limited from reaching a threshold value by selection and design of platens with sufficient thermal mass. In some embodiments, the temperature controller may actively control the flow of a coolant fluid to reduce the temperature in the platens, or use a thermo-electric cooling device. 
     In some embodiments, the device is configured to trap alkali metal  103  between two porous, non-flammable members with a high thermal capacity, to limit the overall temperature rise. Pure water can be introduced into this sandwich, which will react with alkali metal  103 ; however there will be no combustion of the hydrogen because the high heat capacity metal (with a high thermal conductivity) will limit the overall and local temperature increases. Some embodiments incorporate a lock  740  so that platens  702  lock together, the temperature and/or time is monitored, platens  702  unlock, and a visual or audible signal alerts the user to remove used patch  101 . 
     In some embodiments, a rapid dissolution liquid (e.g., water or water/PG mixture with 10% water or more) could be loaded into a sponge on platen  702   a  (or injected after the two platens are closed). Platens  702  could then be closed, trapping the reaction and allowing (with vents for the hydrogen) the thermal mass of the two platens to limit the reaction temperature maintaining a temperature below the melting point of alkali metal  103  and the auto-ignition temperature of the hydrogen. In some embodiments, platens  702  may form small vents when closed (e.g., valves  711 ), to allow for hydrogen egress from the interior. 
     In some embodiments, the semi-permeable membrane covering the adhesive and also alkali metal  103  in used patch  101  has the benefit of trapping unreacted alkali metal to prevent beads of molten metal to egress from the device in case the reaction is sufficiently fast, such that the alkali metal melts. Some embodiments include a liquid disposal feature  745  such as a channel or trench so that any residual liquid (e.g., alkali hydroxide and water) may be disposed of. Some embodiments may include a resident sponge to collect any residual liquid, to be disposed after use. Some embodiments may include a disposal container having a buffer solution to neutralize the alkali hydroxide that then may be emptied into standard waste streams or discarded as a unit. 
       FIG. 8  is a flow chart illustrating steps in a method  800  for disposing of a used patch, according to some embodiments. 
     Step  802  includes placing into a container a device including a laminate of an adhesive and a film having an alkali metal layer or coating and an oxide or hydroxide of the alkali metal. In some embodiments, step  802  includes placing the device in a container through a closable opening in the container. In some embodiments, step  802  includes placing the device in a container including a wall and a bottom wall attached to the wall, wherein the wall includes a front wall and a rear wall, and the bottom wall is attached to the front wall and the rear wall. 
     Step  804  includes controllably exposing, or contacting, the film on the device to a reactant for the alkali metal or a solubilizer of the alkali metal. 
     In some embodiments, step  804  may include applying a low water concentration passivating gel with an applicator on the alkali metal. In some embodiments, step  804  includes supplying the low water concentration passivating gel in a packet that acts as its own applicator. 
     Step  806  includes allowing the alkali metal to react with the reactant or to dissolve in the solubilizer to render the alkali metal substantially non-reactive. 
     Step  808  includes optionally disposing of the device, the container, or both. In some embodiments, step  808  includes verifying a completion signal for the neutralization reaction from an indicator prior to disposing of the used device. 
       FIG. 9  is a flow chart illustrating steps in a method  900  for disposing of a used patch, according to some embodiments. 
     Step  902  includes sealing, in a disposal container, a device including a layer having an alkali metal and an oxide or a hydroxide of the alkali metal, wherein the disposal container includes a closeable opening and a semi-permeable membrane. 
     Step  904  includes allowing a water vapor molecule to contact the layer. 
     Step  906  includes controllably oxidizing the alkali metal to form an alkali metal oxide or hydroxide and to generate a hydrogen molecule. 
     Step  908  includes allowing the hydrogen molecule to egress the disposal container via the semi-permeable membrane. 
     As used herein, the phrase “at least one of” preceding a series of items, with the terms “and” or “or” to separate any of the items, modifies the list as a whole, rather than each member of the list (e.g., each item). The phrase “at least one of” does not require selection of at least one item; rather, the phrase allows a meaning that includes at least one of any one of the items, and/or at least one of any combination of the items, and/or at least one of each of the items. By way of example, the phrases “at least one of A, B, and C” or “at least one of A, B, or C” each refer to only A, only B, or only C; any combination of A, B, and C; and/or at least one of each of A, B, and C. 
     To the extent that the term “include,” “have,” or the like is used in the description or the claims, such term is intended to be inclusive in a manner similar to the term “comprise” as “comprise” is interpreted when employed as a transitional word in a claim. The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. 
     A reference to an element in the singular is not intended to mean “one and only one” unless specifically stated, but rather “one or more.” All structural and functional equivalents to the elements of the various configurations described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and intended to be encompassed by the subject technology. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the above description. 
     While this specification contains many specifics, these should not be construed as limitations on the scope of what may be claimed, but rather as descriptions of particular implementations of the subject matter. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination. 
     The subject matter of this specification has been described in terms of particular aspects, but other aspects can be implemented and are within the scope of the following claims. For example, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. The actions recited in the claims can be performed in a different order and still achieve desirable results. As one example, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the aspects described above should not be understood as requiring such separation in all aspects, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. Other variations are within the scope of the following claims. 
     In one aspect, a method may be an operation, an instruction, or a function and vice versa. In one aspect, a claim may be amended to include some or all of the words (e.g., instructions, operations, functions, or components) recited in other one or more claims, one or more words, one or more sentences, one or more phrases, one or more paragraphs, and/or one or more claims. 
     The foregoing description is intended to illustrate various aspects of the instant technology. It is not intended that the examples presented herein limit the scope of the appended claims. The invention now being fully described, it will be apparent to one of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit or scope of the appended claims. 
     To illustrate the interchangeability of hardware and software, items such as the various illustrative blocks, modules, components, methods, operations, instructions, and algorithms have been described generally in terms of their functionality. Whether such functionality is implemented as hardware, software, or a combination of hardware and software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application. 
     As used herein, the phrase “at least one of” preceding a series of items, with the terms “and” or “or” to separate any of the items, modifies the list as a whole, rather than each member of the list (e.g., each item). The phrase “at least one of” does not require selection of at least one item; rather, the phrase allows a meaning that includes at least one of any one of the items, and/or at least one of any combination of the items, and/or at least one of each of the items. By way of example, the phrases “at least one of A, B, and C” or “at least one of A, B, or C” each refer to only A, only B, or only C; any combination of A, B, and C; and/or at least one of each of A, B, and C. 
     The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. Phrases such as an aspect, the aspect, another aspect, some aspects, one or more aspects, an implementation, the implementation, another implementation, some implementations, one or more implementations, an embodiment, the embodiment, another embodiment, some embodiments, one or more embodiments, a configuration, the configuration, another configuration, some configurations, one or more configurations, the subject technology, the disclosure, the present disclosure, other variations thereof and alike are for convenience and do not imply that a disclosure relating to such phrase(s) is essential to the subject technology or that such disclosure applies to all configurations of the subject technology. A disclosure relating to such phrase(s) may apply to all configurations, or one or more configurations. A disclosure relating to such phrase(s) may provide one or more examples. A phrase such as an aspect or some aspects may refer to one or more aspects and vice versa, and this applies similarly to other foregoing phrases. 
     A reference to an element in the singular is not intended to mean “one and only one” unless specifically stated, but rather “one or more.” Pronouns in the masculine (e.g., his) include the feminine and neuter gender (e.g., her and its) and vice versa. The term “some” refers to one or more. Underlined and/or italicized headings and subheadings are used for convenience only, do not limit the subject technology, and are not referred to in connection with the interpretation of the description of the subject technology. Relational terms such as first and second and the like may be used to distinguish one entity or action from another without necessarily requiring or implying any actual such relationship or order between such entities or actions. All structural and functional equivalents to the elements of the various configurations described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and intended to be encompassed by the subject technology. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the above description. No claim element is to be construed under the provisions of 35 U.S.C. § 112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.” 
     While this specification contains many specifics, these should not be construed as limitations on the scope of what may be described, but rather as descriptions of particular implementations of the subject matter. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially described as such, one or more features from a described combination can in some cases be excised from the combination, and the described combination may be directed to a subcombination or variation of a subcombination. 
     The title, background, brief description of the drawings, abstract, and drawings are hereby incorporated into the disclosure and are provided as illustrative examples of the disclosure, not as restrictive descriptions. It is submitted with the understanding that they will not be used to limit the scope or meaning of the claims. In addition, in the detailed description, it can be seen that the description provides illustrative examples and the various features are grouped together in various implementations for the purpose of streamlining the disclosure. The method of disclosure is not to be interpreted as reflecting an intention that the described subject matter requires more features than are expressly recited in each claim. Rather, as the claims reflect, inventive subject matter lies in less than all features of a single disclosed configuration or operation. The claims are hereby incorporated into the detailed description, with each claim standing on its own as a separately described subject matter. 
     The claims are not intended to be limited to the aspects described herein, but are to be accorded the full scope consistent with the language claims and to encompass all legal equivalents. Notwithstanding, none of the claims are intended to embrace subject matter that fails to satisfy the requirements of the applicable patent law, nor should they be interpreted in such a way.