Priprava i karakterizacija modificiranih celulozno acetatnih membrana

undergraduate thesis

• Title (english): Preparation and characterization of modified membranes from cellulose acetate
• Author: Dino Rodić
• Mentor: Elvira Vidović (mentor)
• Committee member: Elvira Vidović (predsjednik povjerenstva)
• Committee member: Krešimir Košutić (član povjerenstva)
• Committee member: Helena Otmačić Ćurković (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2022-09-19, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering

Abstract

Celulozni acetat široko je primjenjivani polimer vrlo dobrih karakteristika te od velike važnosti u modernom dobu koje se suočava s velikim problemima među kojima se ističe i nestašica pitke vode praćena fatalnim ljudskim djelovanjem, klimatskim promjenama i rapidnim porastom svjetske populacije. Problem pitke vode pokušava se riješiti suvremenim membranskim tehnologijama, a među njima je i reverzna osmoza za koju se često koriste membrane koje se proizvode od celuloznog acetata jer su jeftine, lako se proizvode, visoko su vodopropusne i zadržavaju sol u velikom postotku. Ipak, celulozno acetatne membrane imaju i manjkavosti: osjetljive su na promjene pH, smanjuje im se selektivnost s vremenom zbog podložnosti hidrolizi i također se smanjuje i zadržavanje soli porastom temperature. Kako bi se dobile što bolje membrane s poboljšanim svojstvima, potrebno ih je modificirati drugim tvarima. U ovom radu, celulozno acetatne membrane modificirane su s poli (metil-metakrilatom-ko-dimetilaminoetil-metakrilatom) (kraće P(MMA-ko-DMAEMA)) kopolimerom i nanočesticama srebra s ciljem da se dobiju membrane boljih svojstava. Pripremljene su membrane koje su sadržavale 17 i 20 mas. % čistog celuloznog acetata te membrane koje su sadržavale 17% polimerne mješavine CA/P(MMA-ko-DMAEMA) u masenim omjerima 95/5 i 90/10. Uz to, sve pripremljene membrane su modificirane nanočesticama srebra. Pripravljene membrane karakterizirane su pomoću skenirajućeg elektronskog mikroskopa (SEM) kojim je istražena morfologija membrana, infracrvene spektroskopije (FTIR) kojom je istražena kemijska struktura membrana te mjerenjem kontaktnog kuta kao načinom određivanja hidrofilnosti/hidrofobnosti membrana. Membrane su ispitane i u reverzno osmotskom uređaju kako bi im se odredile vrijednosti fluksa i koeficijent zadržavanja. Ispitivanje je provedeno u 3 serije: 1) tlačna obrada membrana, 2) toplinska i tlačna obrada membrana i 3) modifikacija membrana nanočesticama srebra (AgNPs).

Abstract (english)

Cellulose acetate is a widely used polymer with good characteristics and its very important in the modern age which faces major problems, among which the shortage of drinking water, accompanied by fatal human activities, climate changes and the rapid increase of the world population. The problem of drinking water is trying to be solved with modern membrane technologies, and among them is reverse osmosis, for which membranes made from cellulose acetate are often used because they are cheap, easy to produce, highly permeable to water and retain a high percentage of salt. However, cellulose acetate membrane also have shortcomings: they are sensitive to pH changes, their selectivity decrease over time due to susceptibility to hydrolysis, and salt retention also decreases with increasing temperature. In order to obtain the best possible membranes with improved properties, it is necessary to modify them with other substances. In this work, cellulose acetate membranes were modified with poly (methyl-methacrylate-co-dimethylaminoethyl-methacrylate) (briefly P(MMA-ko-DMAEMA)) copolymer and silver nanoparticles in order to obtain membranes with better properties. Membranes containing mass 17% and 20% pure cellulose acetate and membranes containing 17% polymer mixture CA/P(MMA-ko-DMAEMA) in the mass ratios 95/5 and 90/10 were prepared. In addition, all prepared membranes were modified with silver nanoparticles. The prepared membranes were characterized using a scanning electron microscope (SEM) which investigated the morphology of the membranes, infrared spectroscopy (FTIR) which investigated the chemical structure of the membranes, and measuring the contact angle as a way of determining the hydrophilicity/hydrophobicity of the membranes. The membranes were also tested in a reverse osmosis device in order to determine their flux values and retention coefficient. The test was conducted in three series: 1) pressure treatment of membranes, 2) thermic and pressure treatment of membranes and 3) modification of membranes with silver nanoparticles (AgNPs).

• Keywords: reverzna osmoza; celulozni acetat; P(MMA-ko-DMAEMA); nanočestice srebra (AgNPs); membrane
• Keywords (english): reverse osmosis; cellulose acetate; P(MMA-ko-DMAEMA); silver nanoparticles (AgNPs); membranes
• Language: croatian
• URN:NBN: urn:nbn:hr:149:194168
• Study programme: Title: Environmental Engineering - Undergraduate study; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka ekoinženjerstva (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka ekoinženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-03-14 09:06:48