The course of sorptiion reactions of vanadium(V) aqua complex in the intracrystalline space of montmorillonite was studied. An effective sorption was reached after multiple short treatment of montmorillonite with diluted vanadium(V) solution at low pHs. The interactions proceed mainly on the basal planes of clay mineral crystals. After solid phase separation, vanadium(V) in [VO₂(H₂O)_x] ⁺ aqua complex sorbed is partially reduced to vanadium(IV).