Adsorption of iron ions from diluted solutions (10 ⁻⁵–10 ⁻⁴mol/L) of iron(III) chloride on macroporous glass (average pore radius 14.5 ± 0.6 nm) produced from sodium borosilicate glass is investigated. It is shown that the adsorption isotherm in the studied concentration range is in compliance with the Langmuir type. The limiting adsorption in the monomolecular layer and the adsorption equilibrium constant are determined.