Disclosed herein are lithiated cyclodextrin metal organic frameworks and method of making and using the same. A metal organic framework comprising a coordinated network of repeating units extending in three dimensions, wherein the repeating unit comprises a cyclodextrin, a first coordinating metal cation, and a second coordinating metal cation.

A method of obtaining helium from a helium-containing feed gas. Helium-containing feed gas is fed to a prepurifying unit that uses a pressure swing adsorption process to remove undesirable components from the helium-containing feed gas and obtain a prepurified feed gas. The prepurified feed gas is fed to a membrane unit connected downstream of the prepurifying unit and that has at least one membrane more readily permeable to helium than to at least one further component present in the prepurified feed gas. A pressurized low-helium retentate stream that has not passed through the membrane is fed to the prepurifying unit. The pressurized low-helium retentate is used to displace helium-rich gas from an adsorber that is to be regenerated into an already regenerated adsorber.

Disclosed herein are ceramic selective membranes and methods of forming the ceramic selective membranes by forming a selective silica ceramic on a porous membrane substrate.

Methods for purifying a hydrogen gas stream are provided that can include: introducing the hydrogen gas stream into the hydrogen pumping cell, and collecting a purified hydrogen gas from the hydrogen pumping cell. The hydrogen gas stream can include hydrogen sulfide in an amount of about 10 ppm to about 1,000 ppm, and can have a relative humidity of about 0.1% or more at the operational temperature and pressure of the hydrogen pumping cell.

Systems and methods are provided for separating oxygen from air using a sorption/desorption cycle that includes a reduced or minimized difference between the maximum and minimum pressures involved in the sorption/desorption cycle. The reduced or minimized difference in pressures can be achieved in part by using valves that can allow for commercial scale flow rates while avoiding large pressure drops for flows passing through the valves. A rotary wheel adsorbent is an example of a system that can allow for a sorption/desorption cycle with reduced and/or minimized pressure drops across valves associated with the process. Stationary adsorbent beds can also be used in combination with commercially available valves that have reduced and/or minimized pressure drops.

An air separation unit for an OBOGS includes a housing having an inlet for receiving a wet inlet air and an outlet for outputting a dry product gas. The housing includes an outer side wall and annular walls defining a series of concentric annular chambers. A first annular chamber is coupled to the inlet and includes a desiccant material to receive the wet inlet air and output a dried air. An unfilled second annular chamber is coupled to the first annular chamber. A third annular chamber is coupled to the second annular chamber at a first end and the outlet at a second end. The third annular chamber receives air separation material to selectively remove unwanted constituents from the dried air and output the dry product gas. A tap may be coupled to the second annular chamber so that dried air may be removed from the housing.

A carbon molecular sieve (CMS) membrane is made by pyrolyzing a polymeric precursor membrane in a pyrolysis atmosphere containing a sulfur-containing compound.

A separation membrane structure comprises a porous support, a first separation membrane formed on the porous support, and a second separation membrane formed on the first separation membrane. The first separation membrane has an average pore diameter of greater than or equal to 0.32 nm and less than or equal to 0.44 nm. The second separation membrane includes addition of at least one of a metal cation or a metal complex that tends to adsorb nitrogen in comparison to methane.

A separation membrane structure comprises a porous support body, a zeolite membrane formed on the porous support body and comprising pores having a major diameter and a minor diameter. The ratio of a major diameter to a minor diameter is greater than 1.0. The minor diameter is greater than or equal to 0.30 nm and less than or equal to 0.35 nm.

This disclosure relates to new crystalline microporous solids (including silicate- and aluminosilicate-based solids), the compositions comprising 8 and 10 membered inorganic rings, particularly those having IWV topologies having a range of Si:Al ratios, methods of preparing these and known crystalline microporous solids using certain quaternized imidazolium cation templates.