title: Amine-modified SBA-15 and MCF mesoporous molecular sieves as promising sorbents for natural antioxidant. Modeling of caffeic acid adsorption.
abstract: This work presents a detailed study of caffeic acid adsorption on mesoporous SBA-15 and MCF silicas functionalized with (3-aminopropyl)triethoxysilane (APTES) and 3-[2-(aminoethylamino)propyl]trimethoxysilane (AEAPTMS). Synthesized mesoporous adsorbents were characterized using different analytical techniques such as N2 sorption, XRD, TEM, SEM and FT-IR. The adsorption studies of caffeic acid were conducted in various organic solvents. Moreover, the effect of water content in 2-propanol-water mixture on adsorption efficiency was investigated. The experimental data were best fitted to the Langmuir equation, followed by the Temkin, Dubinin-Radushkevich and Freundlich models. The maximum adsorption capacity values calculated from the Langmuir model demonstrated that SBA-15 and MCF silicas modified with AEAPTMS revealed better adsorption properties toward caffeic acid (192.3 and 161.3mg/g, respectively) as compared to the materials modified with APTES (125.0 and 113.6 mg/g, respectively). The obtained results indicate that both SBA-15 and MCF silicas functionalized with AEAPTMS and APTES are promising materials for the entrapment of caffeic acid.
authors.affiliation: Poznan University of Technology, Faculty of Chemical Technology, Institute of Chemistry and Technical Electrochemistry, Berdychowo 4, 60-965 Poznań, Poland. Electronic address: michal.moritz@put.poznan.pl.
authors.forename: Michał
authors.initials: M
authors.lastname: Moritz
authors.affiliation: NanoBioMedical Centre, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland. Electronic address: Malgorzata.Geszke-Moritz@amu.edu.pl.
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Geszke-Moritz
mesh_terms: D000327:Adsorption; D000588:Amines / Q000737:chemistry*; D000975:Antioxidants / Q000737:chemistry*; D002109:Caffeic Acids / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D016062:Porosity; D011437:Propylamines / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics
chemical_list: D000588:Amines; D000975:Antioxidants; D002109:Caffeic Acids; D011437:Propylamines; C509969:SBA-15; D012821:Silanes; D012822:Silicon Dioxide; C477625:amino-propyl-triethoxysilane; C040048:caffeic acid
keywords: Adsorption modeling; Antioxidant entrapment; Silica; Surface modification; Trialkoxysilane