Ti-based MOF derived by functionalization for selective removal of Pb(II) and Hg(II) from aqueous media

•A novel Ti-MOF adsorbent was synthesized by solvothermal method.•Ti-MOF-SH has excellent selectivity and reproducibility for Hg(Ⅱ) and Pb(Ⅱ).•The adsorption mechanism of Ti-MOF-SH is chelation and electrostatic interaction.•The adsorption effect of Ti-MOF-SH on Hg(Ⅱ) is better than that of Pb(Ⅱ).•The adsorption process of Hg(Ⅱ) and Pb(Ⅱ) accords with Langmuir adsorption isothermal model.