Adsorption of impurities in vegetable oil: A molecular modelling study
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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Date
2020-07-01
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Mcode
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Language
en
Pages
11
55-65
55-65
Series
Journal of Colloid and Interface Science, Volume 571
Abstract
Here, the adsorption of impurity species from triglyceride solvent representing a model vegetable oil is studied using atomistic molecular dynamics simulations. We compare the adsorption of water, glycerol, oleic acid, monoolein, and two types of phospholipids on model silica adsorbents differing in their OH-group density, i.e. hydrogen bonding ability, quartz and cristobalite. We find that the species containing charged groups, phospholipids DOPC and DOPE, adsorb significantly stronger than the nonionic impurities. Secondary contribution to adsorption arises from hydrogen bonding capability of the impurity species, the silica surface, and also the triglyceride solvent: in general, more hydrogen bonding sites in impurity species leads to enhanced adsorption but hydrogen bonding with solvent competes for the available sites. Interestingly, adsorption is weaker on cristobalite even though it has a higher hydrogen bonding site density than quartz. This is because the hydrogen bonds can saturate each other on the adsorbent. The finding demonstrates that optimal adsorption response is obtained with intermediate adsorbent hydrogen bonding site densities. Additionally, we find that monoolein and oleic acid show a concentration driven adsorption response and reverse micelle like aggregate formation in bulk triglyceride solvent even in the absence of water. The findings offer insight into adsorption phenomena at inorganic adsorbent - apolar solvent interfaces and provide guidelines for enhanced design of adsorbent materials for example for vegetable oil purification.Description
Keywords
Adsorption, Aggregation, CHARMM, Colloids in oil, Molecular dynamics, Vegetable oil
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Citation
Vuorte, M, Vierros, S, Kuitunen, S & Sammalkorpi, M 2020, ' Adsorption of impurities in vegetable oil: A molecular modelling study ', Journal of Colloid and Interface Science, vol. 571, pp. 55-65 . https://doi.org/10.1016/j.jcis.2020.03.012
