(a) The waveform of the applied bias and the physical process in the AACE filtration (Reproduced from Ref. [146]. Copyright©2019, Springer Nature Limited). Schematics of physicochemical and HW-ACE extraction. (b) In physicochemical adsorption systems, Coulomb repulsion can cause incoming ions to be rejected by the adsorbed charged ions. (c) Competition between uranyl ions and other cations reduces the adsorption of uranyl ions and results in the blocking of active sites. (d) Physical processes in HW-ACE extraction (Reproduced from Ref. [28]. Copyright©2017, Springer Nature Limited).