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Effect of the sol–gel route on the textural characteristics of silica imprinted with Rhodamine B
Author(s) -
de Coelho Escobar Cícero,
dos Santos João Henrique Zimnoch
Publication year - 2014
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.201301143
Subject(s) - porosimetry , adsorption , fourier transform infrared spectroscopy , catalysis , sol gel , selectivity , rhodamine b , chemistry , hydrolysis , molecular imprinting , desorption , chemical engineering , extraction (chemistry) , materials science , chromatography , organic chemistry , porosity , nanotechnology , porous medium , photocatalysis , engineering
A series of silica xerogels that support R hodamine B as a template were synthesized using distinct sol–gel routes, namely, acid‐catalyzed routes, a base‐catalyzed route, acid‐catalyzed with base‐catalyzed (two steps) hydrolytic routes, and a FeCl 3 ‐catalyzed nonhydrolytic route. The extraction methods (thermal, Soxhlet, water washing, and ultrasound) were also evaluated. The resulting xerogels were characterized through porosimetry using nitrogen adsorption/desorption. The samples were further analyzed through small‐angle X ‐ray scattering, Fourier transform infrared spectroscopy, and SEM . The preparation route affected the materials’ textural properties. Extraction was optimized using acid and two‐step routes. The acid route from R hodamine B to R hodamine 6 G generated the highest selectivity factor (2.5). The nonhydrolytic route produced the best imprinting factor. Competitive adsorption was also used, from which the approximate imprinting factor was 2. The cavity shape generated during the production of the imprinted silica dictates the adsorption behavior, not the magnitude of the surface area.