Abstract: A fluid purifying apparatus that includes a manifold that includes a first branch and a second branch, a first check valve coupled to the first branch of the manifold, and a purifier unit that includes a first end and a second end, wherein the first end is coupled to the second branch of the manifold. Also, a fluid purifying apparatus that includes a vessel that includes a first interior compartment for containing a purifier material and a second interior compartment for containment of a fluid containing impurities, wherein the first interior compartment is separated from the second interior compartment by a fluid permeable support, and a rupturable seal.

Abstract: An exemplary method and apparatus for abating reaction products from a vacuum processing chamber includes a reaction chamber in fluid communication with the vacuum processing chamber, a coil disposed about the reaction chamber, and a power source for supplying RF energy to the coil. The coil creates a plasma in the reaction chamber which effectively breaks down stable reaction products from the vacuum processing chamber such as perfluorocarbons (PFCs) and hydrofluorocarbons (HFCs) which significantly contribute to global warming. According to alternative embodiments, the plasma may be generated with grids or coils disposed in the reaction chamber perpendicular to the flow of reaction products from the vacuum processing chamber.

Abstract: A process for treating gaseous emissions generated during the production of carbon anodes in the aluminum industry. In this process, first gaseous emissions generated during green anode preparation are collected and preheated by direct contact with a stream of combustion gases. Second gaseous emissions generated during anode baking are also collected and mixed with the first gaseous emissions to form a gaseous emission mixture. Alumina powder is then injected into the so obtained mixture and the resulting mixture with the alumina injected therein is processed into a dry scrubber that is equipped with a bag filter and is operating at temperatures well above the saturation temperature of tars, so as to obtain a gaseous mixture partially purified and free of fluorides and particulates. The so obtained partially purified gaseous mixture is then processed into an oxidation furnace in order to destroy all the organic compounds contained therein.

Abstract: An apparatus and process for abating at least one acid or hydride gas component or by-product thereof, from an effluent stream deriving from a semiconductor manufacturing process, comprising, a first sorbent bed material having a high capacity sorbent affinity for the acid or hydride gas component, a second and discreet sorbent bed material having a high capture rate sorbent affinity for the same gas component, and a flow path joining the process in gas flow communication with the sorbent bed materials such that effluent is flowed through the sorbent beds, to reduce the acid or hydride gas component. The first sorbent bed material preferably comprises basic copper carbonate and the second sorbent bed preferably comprises at least one of, CuO, AgO, CoO, Co3O4, ZnO, MnO2 and mixtures thereof.

Abstract: A method of treating exhaust gases containing halogen compound, the improvement in that the exhaust gases containing halogen compounds such as halogen gases and/or hydrogen halide gases (halogenated acid gases) are brought into contact with simple metals. The halogen compounds such as acid gases and halogen gases can thereby effectively be removed from the exhaust gases.

Abstract: A fluid storage and dispensing apparatus including a fluid storage and dispensing vessel having a rectangular parallelepiped shape, and an integrated gas cabinet assembly including such fluid storage and dispensing apparatus and/or a point-of-use ventilation gas scrubber in the vented gas cabinet. By the use of physical adsorbent and chemical sorbent media, the gas cabinet can be enhanced in safety of operation, e.g., where the process gas supplied from the gas cabinet is of a toxic or otherwise hazardous character.

Abstract: A method for the recovery or separation of sulfur oxyfluorides from gas mixtures, in which the gas mixture passes through at least one adsorption stage or membrane stage containing or consisting of zeolites with a modulus >10. The sulfur oxyfluorides fixed to the adsorbent may be made available for use after desorption. The sulfur oxyfluorides enriched through the membrane can be re-used directly.

Abstract: Using a distillation separator, a gas to be treated is separated into a plurality of gas groups having different boiling points. Then, the specific gases included in each of the plurality of gas groups separated at the first separator and having similar boiling points are separated using a chromatographic separator. In this manner, specific gases can be separated from the gas to be treated containing a plurality of specific gases.

Abstract: This invention relates to an improvement in a process for removing C2F6 as an impurity from a CF4 containing gas, preferably CF4 produced by the reaction of F2 with carbon. The improvement in the process comprises the steps: contacting the CF4 containing gas, containing C2F6 impurity, with an activated carbon having a CCl4 activity from 43 to 55 in an adsorption bed to effect adsorption of the C2F6 impurity; and, recovering purified CF4 product in the effluent from the adsorbent bed.

Abstract: The present invention relates to a method of purifying gaseous nitrogen trifluoride from CF4 as impurity.

Abstract: A new method for removing HF and related organic fluorides from fluid streams in which the fluoride species exist as impurities and, in particular, from hydrocarbon fluid streams containing no more than about 1.0% by weight total combined fluorides. The method consists of contacting the fluid stream with an adsorbent consisting essentially of activated alumina that has been treated with a promoter material selected from the oxides and phosphates of alkali metals and alkaline earth metals, and mixtures thereof. This is preferably accomplished by providing a suitable absorber vessel charged with the adsorbent to form a fixed bed, and then conducting the fluoride-contaminated fluid through the fixed bed, either in a downflow or an upflow manner.

Abstract: A fluid storage and dispensing system including a vessel containing a low heel carbon sorbent having fluid adsorbed thereon, with the system arranged to effect desorption of the fluid from the sorbent for dispensing of fluid on demand. The low heel carbon sorbent preferably is characterized by at least one of the following characteristics: (i) Heel, measured for gaseous arsine (AsH3) at 20° C. at 20 Torr, of not more than 50 grams AsH3 per liter of bed of the sorbent material; (ii) Heel, measured for gaseous boron trifluoride (BF3) at 20° C. at 20 Torr, of not more than 20 grams boron trifloride per liter of bed of the sorbent material; (iii) Heel, measured for gaseous germanium tetrafluoride (GeF4) at 20° C. at 20 Torr, of not more than 250 grams AsH3 per liter of bed of the sorbent material; (iv) Heel, measured for gaseous arsenic pentafluoride (AsF5) at 20° C.

Abstract: The present invention provides a process for eliminating halogen-containing compounds contained in a gas or a liquid, characterized in that the gas or liquid is brought into contact with a composition based on an alumina and/or a hydrated alumina and at least one compound (A) comprising at least one metallic element selected from metals from groups VIII, IB and/or IIB of the periodic table, and in that the total metallic element(s) content is at most 45% by weight with respect to the total composition weight, the complement by weight preferably comprising in a major part alumina and/or hydrated alumina.

Abstract: An HFBD purification process includes: (a) contacting a composition containing HFBD with an adsorbent to remove from the HFBD at least two impurities selected from the group consisting of water, an alcohol, hydrofluoric acid and a fluorinated olefin, wherein the adsorbent is a solid having an average pore diameter of about 5 Å and the adsorbent is contacted with the HFBD at a rate of at least 2.7 kg of the HFBD per hour; and (b) recovering from the adsorbent a purified HFBD product containing at least 99.9 vol. % HFBD, a reduced amount of the impurities and less than 0.1 vol. % hexafluoro-2-butyne. Alternatively, the process can be conducted at any contacting rate to produce 99.96 vol. % HFBD. The process can also be conducted at any contacting rate in a bed within a column having a length of at least 30 cm and an inner diameter of at least 2.5 cm.

Abstract: A method for the recovery or separation of sulfur oxyfluorides from gas mixtures, in which the gas mixture passes through at least one adsorption stage or membrane stage containing or consisting of zeolites with a modulus >10. The sulfur oxyfluorides fixed to the adsorbent may be made available for use after desorption. The sulfur oxyfluorides enriched through the membrane can be re-used directly.

Abstract: The filter contains about 1-15% lithium hydroxide and about 85-99% hopcalite material, having a particle size of approximately 20 to 100 mesh, and can be used in combination with a chemical oxygen generator for removing chlorine gas and carbon monoxide.

Abstract: Gas mixtures of SF6 and N2, which have been used, for example, as an insulating filler gas for underground cables, for insulating-gas window panes or as a filler gas for car tires and SF6/air mixtures which have been used as a protective gas when casting magnesium can be separated if they are contacted with hydrophobic zeolites of a certain pore size as selective adsorption agent for sulfur hexafluoride. For a relatively high SF6 concentration, the mixture is preferably first subjected to a membrane separation process and the permeate is contacted with the adsorption agent. The invention also relates to an apparatus for carrying out the process. The process may also be used for separating SF6 from exhaust gases.

Abstract: A method and apparatus for controlling or removing mercury, mercury compounds and high molecular weight organics, if present, from a resource recovery exhaust stream by separately adding a carbonaceous char to the flue gas while it is still within the unit. The char can be produced in situ by adding a carbonaceous material and allowing it to thermally decompose.

Abstract: An ion implantation process system, including an ion implanter apparatus for carrying out an ion implantation process. A supply of source gas for the ion implantation process is arranged to flow to the ion implanter apparatus, which discharges an effluent gas stream including ionization products of the source gas during the ion implantation process. The system includes an effluent abatement apparatus for removing hazardous effluent species from the effluent gas stream. The source gas may be furnished from a low pressure gas source in which the source gas is sorptively retained in a vessel on a sorbent medium having affinity for the source gas, and desorbed for dispensing to the process system. A novel scrubbing composition may be employed for effluent treatment, and the scrubbing composition breakthrough of scrubbable component may be monitored with a device such as a quartz microbalance monitor.

Abstract: The filter contains 1-15% lithium hydroxide and about 85-99% hopcalite material, having a particle size of approximately 20 to 100 mesh, and be used in combination with a chemical oxygen generator for removing chlorine gas and carbon monoxide.

Abstract: A decentralized cleaning plant for dry cleaning by removing fluorine containing waste gases from a reduction process in several electrolytic cells for aluminum, comprising: a storing place for aluminum oxide; a transportation system to distribute aluminum oxide from the storing place to the decentralized cleaning plant, a filter portion to store aluminum oxide before and after use in the decentralized cleaning plant; and an exhaust fan integrated with a top filter part of the plant, wherein a chimney and a separate silo are not required.

Abstract: A cleaning agent and a cleaning process for efficiently removing noxious halogen-based gases such as fluorine, chlorine, boron trifluoride, boron trichloride and tungsten hexafluoride from exhaust gases from semiconductor fabrication processes. The cleaning agent is produced by adherently adding alkali metal formate and/or alkaline earth metal formate to activated carbon, or adherently adding alkali metal hydroxide and/or alkaline earth metal hydroxide together with alkali metal formate and/or alkaline earth metal formate to activated carbon. By exposing exhaust gases to the cleaning agent, noxious halogen-based gases in the exhaust gases are efficiently removed with little desorption of halogen-based gases adsorbed on the cleaning agent. Also, the cleaning treatment is further improved in safety and efficiency by a pre-treatment cleaning agent comprising a metal oxide or a metal hydroxide and a post-treatment cleaning agent prepared by adherently adding sodium formate to a metal oxide.

Abstract: The filer contains about 1-15% lithium hydroxide and about 85-99% hopcalite material, having a particle size approximately 20 to 100 mesh, and can be used in combination with a chemical oxygen generator for removing chlorine gas and carbon monoxide.

Abstract: A method for delivering a gas having a proton affinity of less than 866 kJ/mol is disclosed. A support including at least one polymer sufficiently acidic to protonate the gas is contacted with the gas to protonate the gas. The protonated gas condenses to form a solid salt which is sorbed by the support. The gas is dispensed by deprotonating the sorbed solid salt to regenerate said gas. The at least one polymer of the support has a first Hammett acidity value greater than a second Hammett acidity value of a conjugate acid of the gas. Also provided is an apparatus for performing the method. The invention is especially useful for storing, transporting and delivering hazardous gases, such as arsine and phosphine. The polymer can be polymeric sulfonic acids, polymeric perfluoroalkylsulfonic acids, fluorinated sulfonic acid polymers, cross-linked sulfonated polystyrene-divinylbenzene macroreticular copolymers, carboxylic acid polymers, halogenated carboxylic acid functionalized polymers and mixtures thereof.

Abstract: A system for discharging gas emitted from an apparatus or facility having a vacuum pump which sucks the gas emitted from the apparatus or facility while being supplied with a gas other than the sucked gas, the system comprising a unit for recovering at least part of the gas discharged from the vacuum pump, and recirculating the recovered gas to the vacuum pump as the gas other than the sucked gas. Part of the recovered gas may be recirculated to the apparatus or facility emitting the gas. The system reduces or eliminates emission to the atmosphere of global warming gases such as perfluorocompounds discharged from the vacuum pump, and also reduces the energy required for operating the vacuum pump. A method for discharging gas emitted from an apparatus or facility using a vacuum pump, wherein emission of global warming gases to the atmosphere is reduced or eliminated, is also disclosed.

Abstract: An apparatus and a method for trapping a toxic gas contained in an exhaust gas from a process chamber are disclosed. In the apparatus, two toxic gas traps are provided which are connected in series with a toxic gas sensor provided thereinbetween and in fluid communication with the two traps. When toxic gas is detected by the toxic gas sensor, i.e., an indication that the first toxic gas trap is fully consumed, the second toxic gas trap is used to replace the first toxic gas trap, while a new toxic gas trap is installed as the second toxic gas trap. The present invention novel apparatus and method enables the full use or utilization of a toxic gas trap and results in significant cost savings. Furthermore, the present invention novel apparatus and method improves the yield of a fabrication process by reducing the machine down time since the service frequency for the chamber is reduced.

Abstract: A CVD device A is provided which is equipped with a gas introduction part A3 having an inert gas supply part G1 for supplying a diluting inert gas and a cleaning gas supply path G2 for supplying a cleaning gas, each connected therewith, and equipped with an exhaust gas discharge part A4 for releasing an exhaust gas; an exhaust gas circulation part D1 for circulating an exhaust gas from the CVD device, a cooling part D4 for cooling down and liquefying the cleaning gas in the exhaust gas, and a recovery part 4 for recovering the cleaning gas liquefied in said cooling part D4; the diluting inert gas is composed of a gas having a boiling point lower than that of the cleaning gas; a supply part 6 for supplying a cooling inert gas having the same composition as the diluting inert gas in a liquid state, an inert gas circulation part D3 which is cooled down by heat of evaporation of the cooling inert gas, and an inert gas discharge part 7 for discharging the cooling inert gas evaporated in the inert gas circulation p

Abstract: A process for separating at least one of CF4 and C2F6 from a gas. The process includes the steps of: (a) contacting a gas mixture comprising (i) at least one of CF4 and C2F6, (ii) at least one of NF3, CHF3, and N2, and (iii) SF6 with a membrane at conditions effective to obtain a retentate stream rich in SF6 and at least one of CF4 and C2F6, and a permeate stream rich in at least one of NF3, CHF3, and N2; and (b) contacting the retentate stream with an adsorbent at conditions effective to adsorb SF6 and produce a product stream rich in at least one of CF4 and C2F6.

Abstract: The filter contains about 1-5% lithium hydroxide and about 85-99% hopcalite material, having a particle size of approximately 20 to 100 mesh, and can be used in combination with a chemical oxygen generator for removing chlorine gas and carbon monoxide.

Abstract: The invention relates to a process for removing hydrogen halides from hydrocarbon-containing streams. More particularly, the invention relates to a process and an HCl sorbent for the removal of HCl and other hydrogen halides from hydrocarbon streams to prevent the formation of green oils. The sorbent has an increased capacity for the sorption of HCl and a reduced catalytic activity for the formation of green oils which, surprisingly, results from the pre-loading of water on a sodium promoted alumina adsorbent. The pre-loading of water on the sodium promoted alumina adsorbent in the range of about 5 to about 11 percent of the essentially water-free adsorbent increases the HCl sorption capacities by about 25% with a corresponding decrease in catalytic reactivity.

Abstract: A method of processing semiconductor manufacturing exhaust gases for recovering at least hexafluoroethane in which a feed stream composed of the exhaust gases is passed through an adsorbent bed selected to adsorb oxygen, and also nitrogen if present, but not to appreciably adsorb the hexafluoroethane. As a result, a product stream, discharged from the adsorbent bed, has a higher concentration of hexafluoroethane than in the feed stream. In one embodiment, only a single adsorbent such as carbon molecular sieve is provided to adsorb the oxygen or a modified 4A zeolite could be used to adsorb both oxygen and nitrogen. When nitrogen is a potential constituent, layers of carbon molecular sieve and zeolite are provided to adsorb the oxygen and then the nitrogen, respectively. A third adsorbent, preferably 5A zeolite may be provided in addition to the foregoing two adsorbents to also adsorb any carbon tetrafluoride produced as a by-product.

Abstract: SF.sub.6 gas is collected from the inside of a gas insulated machine during maintenance and inspection and is refined. Compositions of the refined SF.sub.6 gas are analyzed and confirmed to be reusable at the site. In the process of SF.sub.6 gas collecting and refining, acidic gases are neutralized and removed by a dry method using filters and the refined SF.sub.6 gas is collected in a collecting tank. In particular, after the refining, the composition of the collected SF.sub.6 gas is measured and confirmed by analysis equipment to quantitatively confirm whether or not the refined SF.sub.6 gas is reusable.

Abstract: A system for the storage and delivery of a sorbable fluid, comprising a storage and dispensing vessel containing a sorbent material having sorptive affinity for the sorbable fluid, and from which the fluid is desorbable by pressure-mediated and/or thermally-mediated desorption, wherein the sorbent material is functionally enhanced by a reagent which alters the binding energy of the fluid to the sorbent. In a preferred aspect, the system is arranged for storage and delivery of B.sub.2 H.sub.6, in which the sorbent material has sorptive affinity for B.sub.2 H.sub.6 and is effective when B.sub.2 H.sub.6 is contacted with the sorbent to convert B.sub.2 H.sub.6 to a sorbed .BH.sub.3 form, which is desorbable by pressure-mediated desorption and/or thermally-mediated desorption to release B.sub.2 H.sub.6 from the sorbent, and means for selectively discharging desorbed B.sub.2 H.sub.

Abstract: A process for the separation and recovery of fluorochemicals from a gas stream containing a diluent gas and fluorochemicals by contact of the gas stream with a membrane system in combination with an adsorption system, the adsorption system used either before or after the membrane system.

Abstract: A device for removing at least laughing gas and anesthetic vapor from a gas sample based on a molecular sieve shall be improved such that it possesses good adsorption properties for both gas components. A molecular sieve arrangement is provided, which is flown through from a gas inlet to a gas outlet and comprises a first molecular sieve area with a first pore size between about 0.3 nm and 0.5 nm and a second molecular sieve area with a second pore size between about 0.8 nm and 1 nm.

Abstract: Processes and systems to recover at least one perfluorocompound gas from a gas mixture are provided. In one embodiment the inventive process comprises the steps of a) providing a gas mixture comprising at least one perfluorocompound gas and at least one carrier gas, the gas mixture being at a predetermined pressure; b) providing at least one glassy polymer membrane having a feed side and a permeate side; c) contacting the feed side of the at least one membrane with the gas mixture; d) withdrawing from the feed side of the membrane as a non-permeate stream at a pressure which is substantially equal to the predetermined pressure a concentrated gas mixture comprising essentially the at least one perfluorocompound gas; and e) withdrawing from the permeate side of the membrane as a permeate stream a depleted gas mixture comprising essentially the at least one carrier gas.

Abstract: A method for the removal and rapid decomposition of halogenated fumigation agents is described. A fumigation agent, such as methyl bromide, contained in the gas stream exiting a fumigation chamber or structure is captured on activated carbon or other retentive substrate and rapidly decomposed using thiosulfate and water. The method provides an inexpensive, safe, and on-site executable way to remove and detoxify methyl bromide from fumigation discharge gases, thereby reducing or eliminating methyl bromide emissions into the atmosphere.

Abstract: A process is disclosed for separating HF from organics by passing a mixture of HF and organics through a column or bed containing a polymer which sorbs the HF leaving an essentially pure organic stream. The HF may be recovered from the polymer, or the organics may be recovered with reduced HF concentration. The HF and organics may form an azeotropic or azeotrope-like mixture.

Abstract: The gas stream which is produced in and emanates from landfills, anaerobic digesters and other waste gas streams, is treated to produce a purified gas which is essentially a hydrocarbon such as methane and which can be used as the fuel source in a fuel cell power plant. The gas stream passes through a simplified purification system which removes essentially all of the sulfur compounds, hydrogen sulfide, and halogen compounds from the gas stream. The resultant gas stream can be used to power a fuel cell power plant which produces electricity, or as a hydrocarbon fuel gas for other applications.

Abstract: A process for recovering at least one of CF.sub.4 and C.sub.2 F.sub.6 from a vent gas from an aluminum electrolysis cell. The process includes the steps of:(a) removing inorganic fluorides from a vent gas comprising inorganic fluorides and at least one of CF.sub.4 and C.sub.2 F.sub.6 to obtain a purified vent gas; and(b) contacting the purified vent gas with a membrane at conditions effective to obtain a retentate stream rich in at least one of CF.sub.4 and C.sub.2 F.sub.6, and a permeate stream depleted in at least one of CF.sub.4 and C.sub.2 F.sub.6.

Abstract: A method for separating hydrogen fluoride from a chemical mixture is provided. In the process of the invention, hydrogen fluoride is separated from a chemical mixture containing hydrogen fluoride by contacting the chemical mixture with a hydrogen fluoride binder. The separated hydrogen fluoride may be recovered from the hydrogen fluoride binder.

Abstract: Processes and systems to recover at least one perfluorocompound gas from a gas mixture are provided. In one embodiment the inventive process comprises the steps of a) providing a gas mixture comprising at least one perfluorocompound gas and at least one carrier gas, the gas mixture being at a predetermined pressure; b) providing at least one glassy polymer membrane having a feed side and a permeate side; c) contacting the feed side of the at least one membrane with the gas mixture; d) withdrawing from the feed side of the membrane as a non-permeate stream at a pressure which is substantially equal to the predetermined pressure a concentrated gas mixture comprising essentially the at least one perfluorocompound gas; and e) withdrawing from the permeate side of the membrane as a permeate stream a depleted gas mixture comprising essentially the at least one carrier gas.

Abstract: The present invention relates to a process for recovering sulfur hexafluoride ("SF.sub.6 "). More specifically, the invention provides a pressure swing adsorption--desorption process for recovering SF.sub.6 from a gas stream using zeolites, activated carbons, or silicalites to adsorb the SF.sub.6.

Abstract: To dispose of halogenated hydrocarbons one uses a solid sorbent containing an iron oxide and/or iron oxyhydroxide.

Abstract: A process for removing a carbon dioxide, HF or sulfur dioxide contaminant from an exhaust gas stream containing that contaminant comprising providing a gas stream to a reaction zone, the gas stream entering the reaction zone from underneath and being caused to flow through the reaction zone with components of velocity in substantially upwards and circumferential directions; contacting the gas stream in the reaction zone with particulate material to adsorb the contaminant on the particulate material, wherein the flow of gas in the reaction zone causes a dispersed toroidal bed of particulate material to be formed in the reaction zone; the slip velocity of the gas stream relative to the particulate material in the toroidal bed is greater than 1 m/s; and entraining a fine fraction of the particulate material in the gas stream whereby the fine fraction is removed from the toroidal bed by the gas stream exiting the bed; and separately recovering a coarse fraction of the particulate material from the reaction zone.

Abstract: Acidic halides, especially chlorides, in two phase (vapor and hydrocarbon liquid) reactor effluent are separated and at least the halides in the vapor fraction neutralized in a vapor/liquid separator with an alkaline neutralization medium such as an alumina treater impregnated with NaOH. The treater may remove halides from both the vapor and liquid phase within the separator.

Abstract: Acidic halogens, especially chlorides, are removed from a dry gas stream by contact with dry particles of solid caustic. The solid caustic particles are preferably non-porous, and disposed in a bed with at least a 10% bed interstitial volume. Limiting halogen content in gas, and operating with a bone dry gas, ensures that salts deposit on the surface of the solid caustic without plugging the bed of solid caustic. Efficient halogen removal can be achieved even when treating a bone dry gas, one having less than 10 ppmv water vapor, at ambient temperature, without plugging the bed.

Abstract: Acidic halides, especially chlorides, are removed from gas by contact with particles of solid caustic covered by aqueous and hydrocarbon phases, respectively. Effective neutralization is achieved without swelling or plugging the bed of solid caustic. Halides are removed as brine. Efficient caustic utilization is achieved by controlling water vapor levels in the gas based on pH of brine product.

Abstract: HF can be recovered from aqueous streams, particularly those which are dilute and have a concentration of HF lower than the azeotrope between HF and water. Such aqueous streams are contacted with carbon molecular sieves, preferably those having an average pore size of about 3.5 Angstroms, which adsorb both HF and water. When regenerated by heating, more dilute aqueous streams are desorbed at lower temperatures, followed by desorption of HF which is free of water, making possible a separation of HF and water and avoiding formation of the azeotrope.

Abstract: An HCl adsorbent, and method of making and using the adsorbent, the adsorbent comprising an activated alumina promoted with an alkali metal in an amount such that if calculated as alkali metal oxide, the adsorbent contains at least about 5% by weight alkali metal oxide.