Surface modification of MCM-41 and its application in DNA adsorption

Three types of MCM-41 absorbents, namely, Al;–MCM-41, La;–MCM-41, and Zn;–MCM-41, were prepared through amine grafting, phosphonate modification, and metal ion chelation and characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and N2adsorption–desorption analysis. Results revealed that functionalized MCM-41 maintains the original structure of the molecular sieve and that the pore diameter and surface area are reduced compared with those of pure MCM-41. The adsorption behavior of DNA molecules on the surface of the modified molecular sieves was discussed according to the hard-soft acid–base（HSAB） principle. Experimental results showed that DNA purification could be effectively carried out on functionalized MCM-41 and that DNA is easily released by3–4 molL;NaCl solution. This study could be used as a general platform for future work on DNA adsorption and enrichment.