Dopamine functionalized tannic-acid-templated mesoporous silica nanoparticles as a new sorbent for the efficient removal of Cu 2+ from aqueous solution.

A simple, environmentally friendly and cost-effective nonsurfactant template method was used to synthesize tannic-acid-templated mesoporous silica nanoparticles (TMSNs), and then dopamine functionalized TMSNs (Dop-TMSNs) which was synthesized by a facile and biomimetic coating strategy, was developed as a new sorbent for the removal of Cu2+ from aqueous solution. The Dop-TMSNs were thoroughly characterized by SEM, TEM, BET, FT-IR and TGA, and the effects of contact time, initial pH, K+ and Na+ concentrations, co-existing polyvalent metal ions and adsorption-desorption cycle times on the sorption capacity of Dop-TMSNs were studied. It was demonstrated that the maximum adsorption capacity of Cu2+ by Dop-TMSNs was 58.7 mg/g at pH 5.5, and the sorption reached equilibrium within 180 min. Moreover, the K+ and Na+ concentrations had a very slight influence on the sorption process and the adsorption capacity of the Dop-TMSNs still remained 89.2% after recycling for four times. All the results indicated that the Dop-TMSNs could be utilized as an excellent sorbent for the sequestration of Cu2+ .