Cu(II) adsorption by halloysites intercalated with sodium acetate

► Intercalated halloysites with sodium acetate were prepared and characterised by XRD, FTIR, SEM, and specific area evaluation. ► The most intercalated sample evidences a proliferation of nanotubes, consequence of unfolding of the curved tubes. ► The intercalation products were used for removing copper(II) from aqueous solutions. ► The results were discussed as a function of intercalation rate. ► The most intercalated solid, i.e., 91%, was found to be very effective as adsorbent.