Synthesis and characterization of novel mesoporous silicas of the MSU-X family for environmental applications.

Submicron particles of mesoporous MSU-2 silica have been obtained by using Tergitol NP-9 as nonionic surfactant and TEOS as silica precursor. The material has been chemically modified with 5-mercapto-1-methyltetrazole and characterized by powder X-ray diffraction, TEM, SEM, N2 adsorption, FT-IR spectroscopy, 29Si-NMR spectroscopy, thermogravimetric analysis and elemental analysis. The enviromental application of such material (denoted MTTZ-MSU-2b) in the treatment of heavy metal-contaminated waters has been demonstrated. The maximum adsorption capacity of this material was found to be 0.73 +/- 0.01 mmol/g for Pb(II) and 0.94 +/- 0.01 mmol/g for Zn(II), and is higher than the capacity of most of the other functionalized mesoporous materials previously reported. The very high access of these metal ions to the binding sites in the adsorbent has also been demonstrated (adsorption efficiency equal to 0.88 and 1.13 for Pb(II) and Zn(II), respectively).