Natural gas may be purified by removing C.sub.3+ hydrocarbons and CO.sub.2 in respective one or more separation units to yield conditioned gas lower in C.sub.3+ hydrocarbons and CO.sub.2 in comparison to the un-conditioned natural gas. Notably, the feed gas need not be subjected to joule-thomson expansion and molecular sieve dehydration performed by conventional processes. Rather, any water-rich reject stream from the separation unit(s) is dried downstream with a smaller compressor and smaller molecular sieve or gas separation membrane dehydration unit before it may be re-injected deep underground or deep under the sea bed.

Natural gas may be purified by removing C.sub.3+ hydrocarbons and CO.sub.2 in respective one or more separation units to yield conditioned gas lower in C.sub.3+ hydrocarbons and CO.sub.2 in comparison to the un-conditioned natural gas. Notably, the feed gas need not be subjected to joule-thomson expansion and molecular sieve dehydration performed by conventional processes. Rather, any water-rich reject stream from the separation unit(s) is dried downstream with a smaller compressor and smaller molecular sieve or gas separation membrane dehydration unit before it may be re-injected deep underground or deep under the sea bed.

A method of synthesizing cyclohexanone can include oxidation of cyclohexane to produce a mixture including cyclohexanone, cyclohexanol, and cyclohexane, and separating cyclohexanone from the mixture using a pervaporation method. The pervaporation method includes contacting the mixture with a first side of a poly(styrene-maleic anhydride-dihydropyrane) membrane and receiving the cyclohexanone from a second side of the poly(styrene-maleic anhydride-dihydropyrane) membrane as a low-pressure vapor. The method can be performed in a pervaporation unit including a reactant portion for receiving the cyclohexane, a permeate portion for receiving the cyclohexanone, and a poly(styrene-maleic anhydride-dihydropyrane) membrane separating the reactant portion from the permeate portion.

A graft copolymer including zwitterionic repeat units and hydrophobic repeat units, in which the zwitterionic repeat units constitute 2-60 wt % of the graft copolymer and each of the hydrophobic repeat units is characterized in that a homopolymer formed thereof is miscible with polyvinylidene fluoride, polysulfone, poly ether sulfone, polyvinyl chloride, or polyacrylonitrile, each of the hydrophobic repeat units not being a repeat unit of polyvinylidene fluoride. Also disclosed is a filtration membrane containing such a graft copolymer or a statistical copolymer that includes the same composition of repeat units as the graft copolymer. Further disclosed are methods of preparing the graft copolymer and the filtration membrane.

A graft copolymer including zwitterionic repeat units and hydrophobic repeat units, in which the zwitterionic repeat units constitute 2-60 wt % of the graft copolymer and each of the hydrophobic repeat units is characterized in that a homopolymer formed thereof is miscible with polyvinylidene fluoride, polysulfone, poly ether sulfone, polyvinyl chloride, or polyacrylonitrile, each of the hydrophobic repeat units not being a repeat unit of polyvinylidene fluoride. Also disclosed is a filtration membrane containing such a graft copolymer or a statistical copolymer that includes the same composition of repeat units as the graft copolymer. Further disclosed are methods of preparing the graft copolymer and the filtration membrane.

Provided is a facilitated CO.sub.2 transport membrane having an improved CO.sub.2 permeance and an improved CO.sub.2/H.sub.2 selectivity. The facilitated CO.sub.2 transport membrane includes a separation-functional membrane that includes a hydrophilic polymer gel membrane containing a CO.sub.2 carrier and a CO.sub.2 hydration catalyst. Further preferably, the CO.sub.2 hydration catalyst at least has catalytic activity at a temperature of 100 C. or higher, has a melting point of 200 C. or higher, or is soluble in water.

Provided is a facilitated CO.sub.2 transport membrane having an improved CO.sub.2 permeance and an improved CO.sub.2/H.sub.2 selectivity. The facilitated CO.sub.2 transport membrane includes a separation-functional membrane that includes a hydrophilic polymer gel membrane containing a CO.sub.2 carrier and a CO.sub.2 hydration catalyst. Further preferably, the CO.sub.2 hydration catalyst at least has catalytic activity at a temperature of 100 C. or higher, has a melting point of 200 C. or higher, or is soluble in water.

A filtering device for obtaining a chemical liquid by purifying a liquid to be purified has an inlet portion, an outlet portion, a filter A, at least one filter B different from the filter A, and a flow path which includes the filter A and the filter B arranged in series between the inlet portion and the outlet portion and extends from the inlet portion to the outlet portion, in which the filter A has a porous base material made of polyfluorocarbon and a coating layer which is disposed to cover the porous base material and contains a first resin having a hydrophilic group.

Described herein are water desalination membranes and methods of desalinating water. Sulfonated poly(arylene ether) polymers are also disclosed, including those comprising one or more sulfonate groups at various points along the polymer chain. The polymers may be used as at least a portion of a water desalination membrane. The polymers described herein are useful for preventing transport of aqueous ionic species (e.g., Na.sup.+ and Cl.sup.) across a membrane made from the polymers while allowing water to pass. Chlorine-stable polymers are described, as well as polymers exhibiting good performance for rejecting monovalent cations in the presence of polyvalent cations.

The present application discloses a polymer material, membrane and coating as well as preparation methods and applications thereof. The polymer material is formed by the phase inversion of a polymer compound containing an ionizable hydrophilic group and the ionization of the hydrophilic group. The polymer material has a static contact angle of greater than 140 and an adhesive force of less than 10 N with respect to multiple oil phase systems in water. The polymer material provided by the present application has an underwater super-hydrophobic property and an anti-adhesion function not only to diesel, oil, edible oil and other low-viscosity light oil and numerous water-immiscible organic solvents, but also to petroleum, heavy oil, silicone oil, heavy diesel and other high-viscosity oil. A membrane, coating and the like formed from the polymer material is resistant to oil adhesion and contamination in water along with a self-cleaning effect, and thus has a broad application prospect in a variety of fields.