Intenzifikacija prijenosa tvari u sustavima kapljevina-kapljevina i krutina-kapljevina primjenom ekološki prihvatljivih otapala i nanosuspenzija

doctoral thesis

• Title (english): Intensification of mass transfer in liquid-liquid and solid-liquid systems using environmentally friendly solvents and nanosuspensions
• Author: Anamarija Mitar
• Mentor: Jasna Prlić Kardum (mentor)
• Committee member: Aleksandra Sander (predsjednik povjerenstva)
• Committee member: Stanislav Kurajica (član povjerenstva)
• Committee member: Martina Hrkovac (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2021-06-18, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Chemical Engineering; Mechanical, Thermal and Separation Processes
• Universal decimal classification (UDC): 66 - Chemical technology. Chemical and related industries

Abstract

Izbor otapala u industrijskim procesima zahtjevan je postupak budući da korištenje konvencionalnih organskih otapala može predstavljati opasnost za ljudsko zdravlje i okoliš. Istraživanje i primjena niskotemperaturnih eutektičkih otapala (engl. deep eutectic solvent, DES) u ekstrakcijskim procesima, zbog njihova „zelenog“ karaktera, otvara mnoge mogućnosti i moglo bi značajno doprinijeti napretku zelenih tehnologija te smanjiti negativan utjecaj industrije na okoliš. U ovom radu provedena je fizikalno-kemijska karakterizacija pripravljenih DES-ova s različitim udjelom vode. Nadalje, provedena je karakterizacija nanosuspenzija pripremljenih s DES-ovima kao baznim fluidima i aluminijev oksid Al2O3 nanočesticama te im je određena stabilnosti kroz dulji vremenski period. Provedeni su procesi šaržne i kontinuirane ekstrakcije kapljevito-kapljevito i ekstrakcije čvrsto-kapljevito primjenom DES-ova. Istražen je utjecaj različitih procesnih uvjeta te je ispitana mogućnost poboljšanja prijenosa tvari primjenom nanosuspenzija. Ekstrakcija kapljevina-kapljevina ispitana je u procesu ekstrakcijske desulfurizacije i denitrifikacije modelnog goriva, a određene su i vrijednosti difuzijskih koeficijenata te koeficijenta kapaciteta. Proces ekstrakcije čvrsto-kapljevito ispitan je u procesu ekstrakcije polifenolnih spojeva iz komine i lišća masline. Nakon provedene ekstrakcija ispitana je stabilnost, mikrobiološka aktivnost i toksičnost dobivenih ekstrakata. Struktura pripremljenih DES-ova znatno utječe na fizikalno-kemijska svojstva DES-ova, a ovisno o primjeni DES-a svojstva se mogu prilagoditi dodatkom vode. Vrijeme i amplituda raspršivanja nanočestica nemaju utjecaj na stabilnost nanosuspenzije, a najbolju stabilnost pokazale su nanosuspenzije pripremljene s DES-ovima s niskom pH vrijednošću. DES-ovi pripremljeni bez vode, manje kiseli i manje polarni uspješniji su u ekstrakciji tiofena dok se piridin uspješnije ekstrahirao s kiselijim i polarnijim otapalima koji u svom sastavu imaju vodu. Primjenom nanosuspenzija u ekstrakciji kapljevina-kapljevina nije ostvareno očekivano poboljšanje prijenosa tvari. Optimizacijom procesa ekstrakcije veća količina polifenola ekstrahirana je povećanjem temperature, primjenom manjih frakcija lišća i DES-a s manjim udjelom vode. Dodatno poboljšanje procesa prijenosa tvari primjenom nanosuspenzija ostvareno je za sve eksperimente provedene s oduljenom kominom i lišćem.

Abstract (english)

The choice of solvents for industrial purposes is a demanding process since the use of conventional organic solvents may present a risk to human health and environment. Research and application of deep eutectic solvents (DESs) in extraction processes, due to their green character, provide many options and could significantly contribute to the advancement of green technologies and reduce the negative impact of industry on the environment. In this research, physicochemical characterization of prepared DESs with different water content was performed. Furthermore, nanosuspensions prepared with DESs as base fluids and aluminium oxide Al2O3 nanoparticles were characterized and their
long-term stability was determined. The processes of batch and continuous liquid-liquid and solid-liquid extraction using DES were optimized, and the possibility of mass transfer improvement with nanosuspensions was investigated. Liquid-liquid extraction was investigated in the process of extractive desulfurization and denitrification of model fuel, and the values of diffusion coefficients and mass transfer coefficient were determined.
The solid-liquid extraction was examined in the process of leaching polyphenolic compounds from olive pomace and leaves. After the leaching process, the stability, microbiological activity and toxicity of the obtained extracts were examined. The structure of the prepared DESs significantly affects the physicochemical properties of DESs, and depending on the application of DESs, the properties can be adjusted by the addition of water. The time and amplitude of nanosparticles dispersion did not affect the stability of the nanofluid, and the most stable nanofluids were prepared with the most acidic DESs. DESs prepared without water, less acidic and less polar were more successful in thiophene extraction while pyridine was successfully extracted with more acidic and polar solvents prepared with water. The application of nanofluids in liquid-liquid extraction did not achieve the expected mass transfer improvement. By optimizing the leaching process, the higher amount of polyphenols was extracted with temperature increase, by applying smaller leaf fractions and DES with lower water content. Additional improvement of the mass transfer process with nanofluids was achieved when defatted olive pomace and leaves were used as feedstock.

• Keywords: denitrifikacija; desulfurizacija; ekstrakcija; nanosuspenzija; polifenoli
• Keywords (english): denitrification; desulfurization; extraction; nanofluid; polyphenols
• Language: croatian
• URN:NBN: urn:nbn:hr:149:907148
• Promotion: 2021
• Study programme: Title: Chemical Engineering and Applied Chemistry - Doctoral course; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje tehničkih znanosti, polje kemijsko inženjerstvo (doktor/doktorica znanosti, područje tehničkih znanosti, polje kemijsko inženjerstvo)
• Type of resource: Text
• Extent: 178 str. ; 30 cm
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2023-06-01 13:02:16