Selective adsorption of 2,4-dinitrophenol on molecularly imprinted nanocomposites of mesoporous silica SBA-15/polyaniline

Abstract

Surface imprinting and adoption of a nano-sized physical form are two effective approaches to overcome the template transfer difficulty within molecularly imprinted polymers (MIPs). This work is an attempt to conquer the problem of template transfer difficulty within MIPs by using a nano-reactor as a substrate for the reaction between the monomer and the template. Negatively charged hexagonal nano-channels of SBA-15 can act as a support for attachment of positively charged aniline monomers and the 2,4-dinitrophenol (2,4-DNP) template. The imprinted and non-imprinted SBA-15/polyaniline nanocomposites were characterized by Fourier transform infrared (FT-IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and nitrogen adsorption-desorption isotherms. The results showed that the synthesized polymer possessed a highly ordered mesoporous structure. The distribution coefficient values of 2,4-DNP, K(d (2,4-DNP)), were estimated as 301.4 ± 2.3 and 101.2 ± 1.0 mL g(-1) for imprinted and non-imprinted polymers (NIP), respectively. The MIP-solid-phase extraction (SPE) process was optimized by evaluating the type of washing solvent and the composition and volume of the eluting solvent. The prepared MIP was used as a selective sorbent for SPE of 2,4-DNP in the presence of phenolic compounds in tap and sea water. The experimental results indicated that the MIP-SPE and NIP-SPE column yielded recoveries higher than 96% and 38%, respectively. The R.S.D. values were also lower than 3.2% and 4.6% for MIP-SPE and NIP-SPE, respectively.

Synthesis of surface nano-molecularly imprinted polymers for sensitive baicalin detection in biological samples

“…The absorptions at 3462 and 1634 cm −1 resulted from O-H vibration, while peaks at 1087 and 818 cm −1 were attributed the Si-O-Si stretching vibration. The observed peak at 1700 cm −1 indicates that C=O stretching vibration on the surface of modified SBA-15 and the relatively strong bands at the range of 2800–3000 cm −1 corresponded to the stretching vibration of C-H bonds from the methyl (or methylene) groups of MPS 22 . Fig.…”

“…Recently, mesoporous silica has attracted considerable attention because of its wide range of applications as adsorbents. Mesoporous silica possesses the following characteristics: well-defined channels, hydrothermal stability 19 , controllable pore sizes 20 , enormous surface area and pore volume 21 , hydrothermal stability and narrow size distribution 22 . These materials are known for promising applications in sorbents, catalysis and sensors 23 .…”

“…These materials are known for promising applications in sorbents, catalysis and sensors 23 . Mesoporous silica SBA-15 was discovered by Zhao et al in 1998 22 and is an attractive candidate for use as adsorbent due to its great advantages. Compared to other mesoporous materials, SBA-15 exhibits larger pore size and thicker pore wall 24 .…”

Synthesis of mimic molecularly imprinted ordered mesoporous silica adsorbent by thermally reversible semicovalent approach for pipette-tip solid-phase extraction-liquid chromatography fluorescence determination of estradiol in milk

“…Moreover, mesoporous silica such as MCM-41 [30,31], SBA-15 [32][33][34], could guarantee high binding capacity and good site accessibility for target molecules because of their uniform ordered structure, high specific surface area, and large pore volume. Recently, the research of mesoporous silica combined molecular imprinting technique has been applied to the recognition of heavy metal ions [35][36], but the reports about the preparation of ordered mesoporous silica materials combined with mimic molecular imprinting techniques for the recognition of small molecules are few, especially for E2.…”

Dummy molecularly imprinted mesoporous silicates for selective adsorption of 2-naphthol

“…Their high surface area, pore homogeneity, and nanoscale pores render imprinted sites readily accessible to substrates. The MIMSs could find applications as catalysts [5], separation media [6,7], adsorption matrices [8], sensors [9] and nanoreactors [10]. Jung et al first reported the plausible adsorption properties of molecularly imprinted mesoporous silica [11].…”