Aminopropyl-Silica Hybrid Particles as Supports for Humic Acids Immobilization

A series of aminopropyl-functionalized silica nanoparticles were prepared through a basic two step sol-gel process in water. Prior to being aminopropyl-functionalized, silica particles with an average diameter of 549 nm were prepared from tetraethyl orthosilicate (TEOS), using a Stöber method. In a...

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Bibliographic Details
Published in:	Materials Vol. 9; no. 1; p. 34
Main Authors:	Sándor, Mónika, Nistor, Cristina Lavinia, Szalontai, Gábor, Stoica, Rusandica, Nicolae, Cristian Andi, Alexandrescu, Elvira, Fazakas, József, Oancea, Florin, Donescu, Dan
Format:	Journal Article
Language:	English
Published:	Switzerland MDPI AG 01-01-2016 MDPI
Subjects:	Acids aminosilane supports Carbon Chemical oxygen demand Chemistry Density Heat resistance Humic acids humic acids immobilization Hydroxyapatite Immobilization Nanoparticles silica hybrid particles Silicon dioxide Sol gel process Zeta potential Romania humic acids immobilization silica hybrid particles sol-gel process aminosilane supports
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Summary:	A series of aminopropyl-functionalized silica nanoparticles were prepared through a basic two step sol-gel process in water. Prior to being aminopropyl-functionalized, silica particles with an average diameter of 549 nm were prepared from tetraethyl orthosilicate (TEOS), using a Stöber method. In a second step, aminopropyl-silica particles were prepared by silanization with 3-aminopropyltriethoxysilane (APTES), added drop by drop to the sol-gel mixture. The synthesized amino-functionalized silica particles are intended to be used as supports for immobilization of humic acids (HA), through electrostatic bonds. Furthermore, by inserting beside APTES, unhydrolysable mono-, di- or trifunctional alkylsilanes (methyltriethoxy silane (MeTES), trimethylethoxysilane (Me₃ES), diethoxydimethylsilane (Me₂DES) and 1,2-bis(triethoxysilyl)ethane (BETES)) onto silica particles surface, the spacing of the free amino groups was intended in order to facilitate their interaction with HA large molecules. Two sorts of HA were used for evaluating the immobilization capacity of the novel aminosilane supports. The results proved the efficient functionalization of silica nanoparticles with amino groups and showed that the immobilization of the two tested types of humic acid substances was well achieved for all the TEOS/APTES = 20/1 (molar ratio) silica hybrids having or not having the amino functions spaced by alkyl groups. It was shown that the density of aminopropyl functions is low enough at this low APTES fraction and do not require a further spacing by alkyl groups. Moreover, all the hybrids having negative zeta potential values exhibited low interaction with HA molecules.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	1996-1944 1996-1944
DOI:	10.3390/ma9010034