Abstract: A weak base anion resin has alkylamine segments covalently bound to cross-linking segments, the alkylamine segments being selected from a group consisting of: vinylamine, N-methylvinylamine, N,N-dimethylvinylamine, N-methyl-N-ethylvinylamine, and N,N-diethylvinylamine, and the weak base anion resin including ions adsorbed to the alkylamine segments. A method for ion exchange includes providing a weak base anion resin, contacting the weak base anion resin with a solution containing ions to one of capture or adsorb ions from solution to the weak base anion resin, and regenerating the weak base anion resin. A method to capture and release an acid gas includes providing a weak base anion resin, contacting the weak base anion resin with a gas including an acid gas to one of capture or adsorb the acid gas from the gas to the weak base anion resin, and regenerating the weak base anion resin to release the acid gas.

Abstract: The present disclosure is directed to an electrodialytic stack with a concentrate stream that moves through a concentrate flow path bounded by a central ion exchange membrane and a first outer ion exchange membrane. A dilute stream moves through a dilute flow path bounded by the central ion exchange membrane and a second outer ion exchange membrane. A redox shuttle loop is separated from the concentrate and dilute streams by the first and second outer ion exchange membranes, respectively. The outer ion exchange membranes are a different type than the central ion exchange membrane. Electrodes are operable to apply a voltage across the stack. At least one collection of ion exchange materials is located in at least one of the flow paths. The ion exchange materials migrate ions between the central ion exchange membrane and at least one of the outer ion exchange membranes.