Mesoporous silica KIT-6 was chemically modified using 3-mercaptopropyltriethoxysilane (3-MPTS) via post-grafting method to prepare functionalized mesoporous KIT-6-SO3H with highly acidic ‒SO3H groups. Thin layers of KIT-6-SO3H coating onto quartz crystal microbalance (QCM) electrodes are employed as a meso-KIT-6-QCM sensor for the adsorptive removal of Pd(II), Cd(II) and Cs(I) ions with a high detection sensitivity. From ICP-OES measurements, the calculated adsorption capacity (Qe) values are much coincide with that obtained from QCM sensor. Due to the synergetic cooperation between high surface area, large pore volumes and active ‒SO3H groups, KIT-6-SO3H exhibited a remarkable adsorption capacity for metal ions. The effect of initial solution pH on the metal ions uptake was carefully studied. Kinetics and isotherm studies further reveal that adsorption of metal ions by KIT-6-SO3H obeys second-order kinetic and Langmuir isotherm, respectively.