Otapanje koloidnih čestica flourita prekrivenih natrijevim poli(4-stirensulfonatom)

master's thesis

• Title (english): Dissolution of fluorite colloid particles coated with sodium poly(4-styrenesulphonate)
• Author: Ivor Vavra Plavšić
• Mentor: Tajana Begović (mentor)
• Mentor: Juraj Nikolić (komentor)
• Committee member: Tajana Begović (predsjednik povjerenstva)
• Committee member: Ivan Nemet (član povjerenstva)
• Committee member: Ivana Biljan (član povjerenstva)
• Committee member: Davor Kovačević (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Defense date and country: 2024-08-29, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry

Abstract

Praćena je kinetika otapanja čestica fluorita u vodi prije i nakon prekrivanja natrijevim poli(4-stirensulfonatom) pri nekoliko različitih pH vrijednosti pomoću fluoridne (F-ISE) i kalcijeve ion-selektivne elektrode (Ca-ISE), pH elektrode te konduktometrijski. Pomoću metoda dinamičkog i elektroforetskog raspršenja svjetlosti praćena je veličina odnosno elektrokinetički potencijal čestica tijekom otapanja. Prisutnost natrijeva poli(4-stirensulfonata) na česticama nakon adsorpcije potvrđena je UV-Vis spektrofotometrijom i elektroforetskim raspršenjem svjetlosti. Mjerenja s ISE pokazala su da se prekrivene čestice otapaju sporije od neprekrivenih, dok su mjerenja provodnosti pokazala suprotno. Mjerenja s F-ISE ukazuju da brzina otapanja neprekrivenih čestica ne ovisi o pH vrijednosti, dok mjerenja s Ca-ISE ukazuju na smanjenje brzine s povećanjem pH. Mjerenjima s ISE uočeno je da se prekrivene čestice otapaju najbrže pri pH = 4, a bez značajne međusobne razlike pri pH = 6 i pH = 8. Mjerenja provodnosti potvrđuju smanjenje brzine otapanja s porastom pH vrijednosti za neprekrivene i prekrivene čestice.

Abstract (english)

The dissolution kinetics of fluorite particles in water were studied before and after coating with sodium poly(4-styrenesulfonate) at various pH values using fluoride (F-ISE) and calcium ion- selective electrodes (Ca-ISE), a pH electrode, and conductometrically. Dynamic and electrophoretic light scattering were used to measure particle size and electrokinetic potential during dissolution. The presence of sodium poly(4-styrenesulfonate) on particles was confirmed by UV-Vis spectrophotometry and electrophoretic light scattering. ISE measurements indicated that coated particles dissolve more slowly than uncoated ones, whereas conductivity measurements showed the opposite. F-ISE data suggested that the dissolution rate of uncoated particles is pH-independent, while Ca-ISE data indicated a decrease in rate with increasing pH value. ISE measurements showed that coated particles dissolved fastest at pH = 4, with no significant difference between pH = 6 and
pH = 8. Conductivity measurements confirmed a decrease in dissolution rate with increasing pH for both coated and uncoated particles.

• Keywords: fluorit; kinetika otapanja; koloidne čestice; natrijev poli(4-stirensulfonat)
• Keywords (english): colloidal particles; dissolution kinetics; fluorite; sodium poly(4-styrenesulfonate)
• Language: croatian
• URN:NBN: urn:nbn:hr:217:266699
• Project: Number: IP-2020-02-9571; Title: Fizikalna kemija procesa na međupovršini mineral/otopina (poli)elektrolita; Title: Physical chemistry of processes at mineral/(poly)electrolyte solution interface; Acronym: POLYMIN2; Leader: Tajana Begović; Jurisdiction: Croatia; Funder: Hrvatska zaklada za znanost; Funding stream: Research Projects
• Study programme: Title: Graduate university studies in chemistry; specializations in: Graduate university studies in chemistry; Course: Graduate university studies in chemistry; Study programme type: university; Study level: graduate; Academic / professional title: sveučilišni/a magistar/magistra kemije (sveučilišni/a magistar/magistra kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Embargoed access; Embargo expiration date: 2025-08-29
• Created on: 2024-10-03 14:37:45