The effect of anodic surface treatment of activated carbons on
their Cr(VI) adsorption properties under reaction-treatment time
conditions with 35 wt.% HCl solution was investigated [75]. The
acidic surface functional groups increased with increasing HCl
reaction-treatment time. Specific surface area, total pore volume,
net heat of adsorption, and BET’s, slightly decreased during
anodic surface treatments of activated carbons. Adsorption was
controlled more by the acid–base interactions between electrondonor
substances and acidized activate