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SBA-15; an investigation into the synthesis solution's effect on formation dynamics and material properties

Anderberg Haglund, Caroline LU (2012) KEMK07 20121
Department of Chemistry
Abstract
The aim of this thesis project was to study the reaction solution’s effect on the formation dynamics and material properties of the mesoporous silica SBA-15.
The common synthesis procedure of SBA-15 was applied at 60°C, with 2.5 wt% Pluronic P104 dissolved in 1.6 M hydrochlorid acid. Simple sodium salts (NaCl, NaBr, NaI) or short to medium length alcohols (MeOH, EtOH, 1-PrOH, 2-PrOH, 1-BuOH, 2-BuOH), in the concentration range 0-1 M, was added prior to the addition of the silica source, tetramethyl orthosilicate. The material was hydrothermally treated and approximately half of the sample was calcined.
UV-Vis spectrophotometry was used to establish the flocculation time. The spectrophotometric measurements showed a decrease in... (More)
The aim of this thesis project was to study the reaction solution’s effect on the formation dynamics and material properties of the mesoporous silica SBA-15.
The common synthesis procedure of SBA-15 was applied at 60°C, with 2.5 wt% Pluronic P104 dissolved in 1.6 M hydrochlorid acid. Simple sodium salts (NaCl, NaBr, NaI) or short to medium length alcohols (MeOH, EtOH, 1-PrOH, 2-PrOH, 1-BuOH, 2-BuOH), in the concentration range 0-1 M, was added prior to the addition of the silica source, tetramethyl orthosilicate. The material was hydrothermally treated and approximately half of the sample was calcined.
UV-Vis spectrophotometry was used to establish the flocculation time. The spectrophotometric measurements showed a decrease in flocculation time for the salts and an increase in flocculation time for the alcohols. The different effects of the additives relate to their effect on the solubility of Pluronic. The salts increase the polarity of the solution, decreasing the solubility of the surfactant. Previous research shows an increased solubility of Pluronic on addition of sodium iodine, a trend not seen here. The added alcohols decrease the polarity of the solution, thus increasing the solubility of Pluronic, a trend not expected for the butanols which acts as cosurfactants.
Small angle x-ray diffraction was used to determine the structure of the products from the syntheses with additives. All, except the highest concentration of 1-butanol showed a hexagonal structure. The unit cell parameter decreased with increasing concentration for all additives.
The morphology of the particles was studied using scanning electron microscopy. The silica with added sodium salts resulted in fibrous particles at the higher concentrations, to different extent depending on the salt species. This oriented aggregation was not seen in the silica with added alcohols, leading to large undefinable particles randomly aggregated. As for the salts, the extent of the effect depends on the alcohol species and concentration, with the largest effect obtained by the alcohols with the longest alkylic chain.
The cause of the unexpected behavior of the sodium iodine and the two types of butanols was not studied in this project and further investigation is needed. (Less)
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author
Anderberg Haglund, Caroline LU
supervisor
organization
course
KEMK07 20121
year
type
M2 - Bachelor Degree
subject
keywords
Fysikalisk kemi
language
English
id
3053641
date added to LUP
2012-09-19 11:50:27
date last changed
2012-09-19 11:50:27
@misc{3053641,
  abstract     = {The aim of this thesis project was to study the reaction solution’s effect on the formation dynamics and material properties of the mesoporous silica SBA-15.
The common synthesis procedure of SBA-15 was applied at 60°C, with 2.5 wt% Pluronic P104 dissolved in 1.6 M hydrochlorid acid. Simple sodium salts (NaCl, NaBr, NaI) or short to medium length alcohols (MeOH, EtOH, 1-PrOH, 2-PrOH, 1-BuOH, 2-BuOH), in the concentration range 0-1 M, was added prior to the addition of the silica source, tetramethyl orthosilicate. The material was hydrothermally treated and approximately half of the sample was calcined.
UV-Vis spectrophotometry was used to establish the flocculation time. The spectrophotometric measurements showed a decrease in flocculation time for the salts and an increase in flocculation time for the alcohols. The different effects of the additives relate to their effect on the solubility of Pluronic. The salts increase the polarity of the solution, decreasing the solubility of the surfactant. Previous research shows an increased solubility of Pluronic on addition of sodium iodine, a trend not seen here. The added alcohols decrease the polarity of the solution, thus increasing the solubility of Pluronic, a trend not expected for the butanols which acts as cosurfactants.
Small angle x-ray diffraction was used to determine the structure of the products from the syntheses with additives. All, except the highest concentration of 1-butanol showed a hexagonal structure. The unit cell parameter decreased with increasing concentration for all additives.
The morphology of the particles was studied using scanning electron microscopy. The silica with added sodium salts resulted in fibrous particles at the higher concentrations, to different extent depending on the salt species. This oriented aggregation was not seen in the silica with added alcohols, leading to large undefinable particles randomly aggregated. As for the salts, the extent of the effect depends on the alcohol species and concentration, with the largest effect obtained by the alcohols with the longest alkylic chain.
The cause of the unexpected behavior of the sodium iodine and the two types of butanols was not studied in this project and further investigation is needed.},
  author       = {Anderberg Haglund, Caroline},
  keyword      = {Fysikalisk kemi},
  language     = {eng},
  note         = {Student Paper},
  title        = {SBA-15; an investigation into the synthesis solution's effect on formation dynamics and material properties},
  year         = {2012},
}