Preparation of silica-based porous materials from starch-derived low molecular weight organic gelator template

Starch, as readily available biomass source, low in cost and renewable biodegradable material, has not been paid enough attention by researchers as a promising candidate for developing sustainable materials. Starch is also referred to as a polysaccharide, mainly composed of two homopolymers of D-glu...

Full description

Saved in:

Bibliographic Details
Main Author:	Matmin, Juan
Format:	Thesis
Language:	English
Published:	2011
Subjects:	TP Chemical technology
Online Access:	http://eprints.utm.my/id/eprint/33400/1/JuanMatminMFS2011.pdf
Tags:	Add Tag No Tags, Be the first to tag this record!

id	my-utm-ep.33400
record_format	uketd_dc
spelling	my-utm-ep.334002018-05-27T08:07:42Z Preparation of silica-based porous materials from starch-derived low molecular weight organic gelator template 2011-08 Matmin, Juan TP Chemical technology Starch, as readily available biomass source, low in cost and renewable biodegradable material, has not been paid enough attention by researchers as a promising candidate for developing sustainable materials. Starch is also referred to as a polysaccharide, mainly composed of two homopolymers of D-glucose, amylose and amylopectin building unit. The present study reports on the chemical modification of starches derived from locallygrown rice and sago to low molecular weight organic gelators (LMWOGs) for application in template-assisted synthesis of porous materials. Both rice and sago starches were modified chemically via acid hydrolysis in aqueous solutions (pH < 2) in order to break down the long branched chain of polysaccharides into much smaller monosaccharide chains of ß-D-glucose. The presence of ß-D-glucose was confirmed by Benedict’s test, FTIR and NMR spectroscopy. The starch derived either from rice or sago showed similar chemical characteristics but exhibited significant differences in their granular arrangements. The rice starch granules were polygonal in shape while those of sago starch were oval shaped as revealed by FESEM micrographs. Synthesis of mesoporous silica-based materials with high surface areas (756 m2 g-1) were performed by employing ß-D-glucose, as organic gelator template and tetraethyl orthosilicate (TEOS) as silica precursor, in a typical HCl-catalyzed sol-gel process. The nature of interaction between silica and LMWOGs was investigated. The results show that LMWOGs act as template for the structuration of silica and the electrostatic interactions at the template-silica interface contribute to the porosity of the materials. The template removal by water as an extraction solvent and followed by calcination at 400°C were evaluated as the best template removal method. Based on the nitrogen adsorptiondesorption isotherms, the pore parameters of the mesoporous silica depend primarily on the amount ratio of modified starch to silica precursor (in % v/v). At low amount of template used (< 40 % v/v) materials with micropores dominant were formed. As the template concentration is increased in medium amount ranging from 45 to 65 %v/v, the relative contribution from mesopores becomes dominant while the presence of excess amount of template resulted in low pressure hysteresis, suggesting the presence of ultramicropores. The mesoporous silica material was inserted with different titanium loadings (1, 3 and 5 wt.%) to generate titanium-silicate catalysts for the oxidation of 1- naphtol to 1,4-naphtoquinone. The catalyst containing 1 wt.% titanium which possessed the highest amount of tetrahedral titanium species as active sites exhibited the highest conversion (44 %) of 1-naphtol towards 1,4-naphtoquinone. 2011-08 Thesis http://eprints.utm.my/id/eprint/33400/ http://eprints.utm.my/id/eprint/33400/1/JuanMatminMFS2011.pdf application/pdf en public masters Universiti Teknologi Malaysia, Faculty of Science Faculty of Science
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	TP Chemical technology
spellingShingle	TP Chemical technology Matmin, Juan Preparation of silica-based porous materials from starch-derived low molecular weight organic gelator template
description	Starch, as readily available biomass source, low in cost and renewable biodegradable material, has not been paid enough attention by researchers as a promising candidate for developing sustainable materials. Starch is also referred to as a polysaccharide, mainly composed of two homopolymers of D-glucose, amylose and amylopectin building unit. The present study reports on the chemical modification of starches derived from locallygrown rice and sago to low molecular weight organic gelators (LMWOGs) for application in template-assisted synthesis of porous materials. Both rice and sago starches were modified chemically via acid hydrolysis in aqueous solutions (pH < 2) in order to break down the long branched chain of polysaccharides into much smaller monosaccharide chains of ß-D-glucose. The presence of ß-D-glucose was confirmed by Benedict’s test, FTIR and NMR spectroscopy. The starch derived either from rice or sago showed similar chemical characteristics but exhibited significant differences in their granular arrangements. The rice starch granules were polygonal in shape while those of sago starch were oval shaped as revealed by FESEM micrographs. Synthesis of mesoporous silica-based materials with high surface areas (756 m2 g-1) were performed by employing ß-D-glucose, as organic gelator template and tetraethyl orthosilicate (TEOS) as silica precursor, in a typical HCl-catalyzed sol-gel process. The nature of interaction between silica and LMWOGs was investigated. The results show that LMWOGs act as template for the structuration of silica and the electrostatic interactions at the template-silica interface contribute to the porosity of the materials. The template removal by water as an extraction solvent and followed by calcination at 400°C were evaluated as the best template removal method. Based on the nitrogen adsorptiondesorption isotherms, the pore parameters of the mesoporous silica depend primarily on the amount ratio of modified starch to silica precursor (in % v/v). At low amount of template used (< 40 % v/v) materials with micropores dominant were formed. As the template concentration is increased in medium amount ranging from 45 to 65 %v/v, the relative contribution from mesopores becomes dominant while the presence of excess amount of template resulted in low pressure hysteresis, suggesting the presence of ultramicropores. The mesoporous silica material was inserted with different titanium loadings (1, 3 and 5 wt.%) to generate titanium-silicate catalysts for the oxidation of 1- naphtol to 1,4-naphtoquinone. The catalyst containing 1 wt.% titanium which possessed the highest amount of tetrahedral titanium species as active sites exhibited the highest conversion (44 %) of 1-naphtol towards 1,4-naphtoquinone.
format	Thesis
qualification_level	Master's degree
author	Matmin, Juan
author_facet	Matmin, Juan
author_sort	Matmin, Juan
title	Preparation of silica-based porous materials from starch-derived low molecular weight organic gelator template
title_short	Preparation of silica-based porous materials from starch-derived low molecular weight organic gelator template
title_full	Preparation of silica-based porous materials from starch-derived low molecular weight organic gelator template
title_fullStr	Preparation of silica-based porous materials from starch-derived low molecular weight organic gelator template
title_full_unstemmed	Preparation of silica-based porous materials from starch-derived low molecular weight organic gelator template
title_sort	preparation of silica-based porous materials from starch-derived low molecular weight organic gelator template
granting_institution	Universiti Teknologi Malaysia, Faculty of Science
granting_department	Faculty of Science
publishDate	2011
url	http://eprints.utm.my/id/eprint/33400/1/JuanMatminMFS2011.pdf
_version_	1747816152058298368

Preparation of silica-based porous materials from starch-derived low molecular weight organic gelator template

Similar Items