Mono- and pentamine immobilized silica were prepared through the treatment of silica with 3-aminopropyltriethoxysilane and 3-glycidoxypropyltrimethoxysialne. The success of immobilization process was confirmed by means of FT-IR and thermogravimetry (TG). The surface properties of the modified silica obtained were investigated by means of nitrogen surface area (BET), pore volume, zeta potential and amine content. The uptake behaviour of the modified silica towards mercury ions at different experimental conditions of pH, time, concentration and temperature using batch and column methods was studied. The maximum uptake values at 293 K were 1.70 and 3.50 mmol g(-1) for MAMS and PAMS, respectively. Kinetics and thermodynamics data showed a pseudo-second order adsorption process with endothermic nature. Regeneration of the modified silica was performed using 0.50 mol dm(-3) KI.