Opis prenosa kisika v mikroreaktorju z membrano

magistrsko delo

Erik Hartman (Author), Polona Žnidaršič Plazl (Mentor), Marjan Marinšek (Thesis defence commission member), Igor Plazl (Thesis defence commission member)

Abstract

V mikrobioreaktorjih moramo pogosto zagotavljati ustrezne koncentracije raztopljenega kisika, ki je nujen za njihovo delovanje oz. ustrezen potek biokemijskih reakcij. Z vgradnjo polprepustnih membran lahko omogočimo zelo učinkovit in kontinuiran transport kisika v mikroreaktorjih iz neprepustnih materialov. Med materiali za izdelavo tovrstnih membran prevladuje polidimetilsiloksan (PDMS). Na prepustnost membrane lahko vplivajo različni procesni parametri pri njeni sintezi, in sicer masni delež zamreževalca v osnovni matrici elastomera, debelina nanosa, temperatura in čas polimerizacije ter posledično tudi končna debelina PDMS membrane. V pričujočem delu smo pri različnih pogojih sintetizirali več različnih PDMS membran, ki smo jih vgradili v mikroreaktorje. Primerjali smo njihovo učinkovitost za prepustnost kisika in povezavo tega parametra s pogoji sinteze. Ugotovili smo, da se membrane z večjo nanašalno debelino lažje odstrani s površine materiala, na katerega so bile nanašene pred polimerizacijo in prav tako se jih lažje vgradi v mikroreaktor. Membranam smo tudi določili končno debelino in Youngov modul. Ugotovili smo, da se debelina membrane med polimerizacijo zmanjša za polovico njene nanašalne debeline in da so membrane, polimerizirane pri krajših časih, bolj elastične. PDMS membrane smo vgradili v mikroreaktorje, kjer smo preučevali koncentracijo raztopljenega kisika oz. kako dobro je membrana prepustna za kisik.. Membrane, sintetizirane pod različnimi pogoji, smo med seboj primerjali. Rezultati analize koncentracije raztopljenega kisika so pokazali, da ima na prepustnost kisika največji vpliv čas polimerizacije, nekoliko manj pa delež zamreževalca in temperatura polimerizacije. Hkrati smo razvili tudi matematični model oz. simulacijo, ki napoveduje koncentracijski profil kisika po dolžini in globini mikroreaktorja, na koncu pa rezultate primerjali z eksperimentalnimi podatki, ki so se med seboj dobro ujemali in tako potrdili učinkovitost sintetiziranih PDMS membran za prepustnost kisika.

Keywords

prenos kisika;koncentracija raztopljenega kisika;mikrokanali;PDMS membrane;polidimetilsiloksan;senzorji kisika;matematično modeliranje;magistrska dela;

Data

Language:	Slovenian
Year of publishing:	2022
Typology:	2.09 - Master's Thesis
Organization:	UL FKKT - Faculty of Chemistry and Chemical Technology
Publisher:	[E. Hartman]
UDC:	66.02(043.2)
COBISS:	98745091
Views:	186
Downloads:	41
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Oxygen transfer description in a microreactor with a membrane
Secondary abstract:	In microbioreactors we must often provide adequate concentrations of dissolved oxygen, which is necessary for their functioning or appropriate course of biochemical reactions. By installing semi-permeable membranes, we can enable very efficient and continuous transport of oxygen into microreactors made of impermeable materials. Polydimethylsiloxane (PDMS) predominates among the materials used to make such membranes. However, the permeability of the membrane can be affected by various process parameters in its synthesis, namely the mass fraction of crosslinker in the base matrix of elastomer, thickness of application, polymerization temperature and time and consequently the final thickness of PDMS membrane. In the present work, several different PDMS membranes were synthesized under different conditions and incorporated into microreactors. We compared their efficiency for oxygen permeability and the association of this parameter with the synthesis conditions. We found that membranes with greater application thickness are easier to remove from the surface of the material to which they were applied before polymerization and are also easier to incorporate into the microreactor. We also determined the final thickness and Young’s modulus for the membranes. We found that the membrane thickness decreases by half its application thickness during polymerization and that membranes polymerized at shorter times are more elastic. PDMS membranes were installed in microreactors, where the concentration of dissolved oxygen was studied or how well the membrane is permeable to oxygen. Membranes synthesized under different conditions were compared with each other. The results of the analysis of the dissolved oxygen concentration showed that the polymerization time has the greatest influence on the oxygen permeability, and to a lesser extent the crosslinker content and the polymerization temperature. At the same time, we also developed a mathematical model or a simulation predicting the oxygen concentration profile along the length and depth of the microreactor and comparing the results with experimental data that matched well and thus confirmed the efficiency of the synthesized PDMS membranes for oxygen permeability.
Secondary keywords:	concentration of dissolved oxygen;microreactor;microchannel;PDMS membrane;Mikroreaktorji;Univerzitetna in visokošolska dela;
Type (COBISS):	Master's thesis/paper
Study programme:	1000376
Embargo end date (OpenAIRE):	1970-01-01
Thesis comment:	Univ. v Ljubljani, Fak. za kemijo in kemijsko tehnologijo, smer Kemijsko inženirstvo
Pages:	59 str.
ID:	14562751