화학공학소재연구정보센터
Journal of Colloid and Interface Science, Vol.240, No.2, 533-538, 2001
Silylating agents grafted onto silica derived from leached chrysotile
Silica from leached chrysotile fibers (SILO) was silanized with trialkoxyaminosilanes to yield inorganic-organic hybrids designated SILx (x = 1-3). The greatest amounts of the immobilized agents were quantified as 2.14, 1.90, and 2.18 mmol g(-1) on SIL1, SIL2, and SIL3 for -(CH2)(3)NH2, -(CH2)(3)NH(CH2)(2)NH2, and -(CH2)(3)N-H(CH2)(2)NH(CH2)(2)NH2 groups attached to the inorganic support. The infrared spectra for all modified silicas showed the absence of the Si-OH deformation mode, originally found at 950 cm(-1), and the appearance of asymmetric and symmetric C-H stretching bands at 2950 and 2840 cm(-1). Other important bands associated with the organic moieties were assigned to nu (as)(NH) at 3478 and nu (sym)(NH) at 3418 cm(-1). The NMR spectrum of the solid precursor material suggested two different kinds of silicon atoms: silanol and siloxane groups, between -90 and 110 ppm; however, additional species of silicon that contain the organic moieties bonded to silicon at -58 and -66 ppm appeared after chemical modification. These modified silicas showed a high adsorption capacity for cobalt and copper cations in aqueous solution, in contrast to the original SILO matrix, confirming the unequivocal anchoring of silylating agents on the silica surface.