A thiol-functionalized magnetic mesoporous silica material (called SH-mSi@Fe3O4), synthesized by a
modified Stöber method, has been investigated as a convenient and effective adsorbent for heavy metal
ions. Structural characterization by powder X-ray diffraction, N2 adsorption–desorption isotherm, Fourier
transform infrared spectroscopy and elemental analyses confirms the mesoporous structure and the
organic moiety content of this adsorbent. The high saturation magnetization (38.4 emu/g) make it easier
and faster to be separated from water under a moderate magnetic field. Adsorption kinetics was
elucidated by pseudo-second-order kinetic equation and exhibited 3-stage intraparticle diffusion mode.
Adsorption isotherms of Hg and Pb fitted well with Langmuir model, exhibiting high adsorption capacity
of 260 and 91.5 mg of metal/g of adsorbent, respectively. The distribution coefficients of the tested metal
ions between SH-mSi@Fe3O4 and different natural water sources (groundwater, lake water, tap water
and river water) were above the level of 105 mL/g. The material was very stable in different water matrices,
even in strong acid and alkaline solutions. Metal-loaded SH-mSi@Fe3O4 was able to regenerate in
acid solution under ultrasonication. This novel SH-mSi@Fe3O4 is suitable for repeated use in heavy metal
removal from different water matrices.