Grafting 3-mercaptopropyl trimethoxysilane on multi-walled carbon nanotubes surface for improving on-line cadmium(II) preconcentration from water samples

► 3-Mercaptopropyl trimethoxysilane grafted on MWCNT surface was prepared. ► The material promoted an increase on performance of MWCNT for Cd2+ adsorption. ► The life time of adsorbent was very high. ► An improvement of 84% on the sensitivity was achieved.