title: Mesoporous silica containing ≡Si(CH2)3NHC(S)NHC2H5 functional groups in the surface layer.
abstract: One-step synthesis technique of mesoporous SBA-15 type silica with thiourea ≡Si(CH(2))(3)NHC(S)NHC(2)H(5) groups in the surface layer was developed. According to elemental analysis, the content of surface groups is 1.25 mmol/g, which is consistent with TGA data. FT-IR spectra of the obtained sample contain characteristic absorption bands of thiourea groups (-NH-C(S)-NH-), as well as polysiloxane network (SiOSi). The synthesized sample was studied by XRD, TEM, SEM, and adsorption method. It was demonstrated that the sample features porous microspheres ~0.5 μm with well-ordered internal spatial structure of the hexagonal lattice type due to the usage of template P123 during synthesis. According to XRD and TEM, the diameter of pores is 4.2-5 nm and the wall thickness between them is 2.6 nm. These data are consistent with the structural-adsorption characteristics calculated from nitrogen adsorption-desorption isotherms: S(sp.)=510 m(2)/g, V(s)=0.47 cm(3)/g, and d=4.3 nm. Equilibrium is established within 60 min during sorption of silver(І) and mercury(ІІ) ions from acidified aqueous solutions for this sample, and with the complexes are formed 1.1/1 for Ag(+) and 0.8/1 for Hg(2+) at metal/ligand ratio.
authors.affiliation: Chuiko Institute of Surface Chemistry, National Academy of Sciences of Ukraine, Kyiv 03164, Ukraine. nazarchuk_g@isc.gov.ua
authors.forename: Galyna I
authors.initials: GI
authors.lastname: Nazarchuk
authors.forename: Inna V
authors.initials: IV
authors.lastname: Melnyk
authors.forename: Yuriy L
authors.initials: YL
authors.lastname: Zub
authors.forename: Olga I
authors.initials: OI
authors.lastname: Makridina
authors.forename: Alexandr I
authors.initials: AI
authors.lastname: Vezentsev