Activated carbon cloth electrodes for capacitive deionization: a neutron imaging study

Neutron imaging was employed to track the uptake of Gd ³⁺ 3 + ions by the sub 2 nm micropores of charged activated carbon cloth electrodes from an aqueous Gd(NO ₃ 3 ) ₃ 3 solution. The transmitted neutron intensity evinces the persistent presence of Gd ³⁺ 3 + in the micropores during the discharge cycle, which is caused by the adsorption of oppositely charged ions. The charge efficiency of the activated carbon cloth system was determined by direct comparison with the imaged Gd ³⁺ 3 + concentration changes, with which the influence of ion swapping and resistive losses on capacitive deionization cells can be ascertained.