Sinteza i karakterizacija koloidnih čestica fluorita

master's thesis

• Title (english): Synthesis and characterization of fluorite colloid particles
• Author: Leonarda Šego
• Mentor: Tajana Begović (mentor)
• Committee member: Tajana Begović (predsjednik povjerenstva)
• Committee member: Iva Juranović Cindrić (član povjerenstva)
• Committee member: Biserka Prugovečki (član povjerenstva)
• Committee member: Davor Kovačević (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Defense date and country: 2022-09-29, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry

Abstract

Sintetizirane su i okarakterizirane koloidne čestice kalcijeva fluorida (fluorita). Sinteza je
provedena pri različitim koncentracijama i omjerima kalcijeva klorida i amonijeva fluorida,
kako bi se ustanovila ovisnost veličine i brzine rasta čestica o početnim koncentracijama i
množinskim omjerima reaktanata. Rendgenskom difrakcijom praha ispitana je čistoća uzorka,
a BET analizom određena je specifična površina. Izoelektrička točka fluorita u suspenziji u
kojoj je omjer reaktanata stehiometrijski te u suspenzijama sa suviškom kalcijevih i fluoridnih
iona određena je elektroforezom. Elektroforezom je određen i utjecaj koncentracije fluoridnih
iona na elektrokinetički potencijal fluorita. Istražena je kinetika otapanja pri dvije pH
vrijednosti za sintetizirane i nabavljene čestice fluorita. Pokazano je da najveće čestice fluorita
nastaju ako se u sintezi koristi suvišak fluoridnih iona, dok je najbrži rast izmjeren za sintezu u
stehiometrijskom omjeru kalcijevih i fluoridnih iona. Potvrđeno je da brzina otapanja fluorita
ovisi o pH. Određeni su koeficijenti brzine otapanja čestica fluorita, te red reakcije otapanja s
obzirom na hidronijeve ione.

Abstract (english)

Colloidal particles of calcium fluoride (fluorite) have been synthesized and characterized. The
synthesis was carried out at different concentrations and ratios of calcium chloride and
ammonium fluoride. The dependence of the size and rate of growth of particles on the initial
concentrations and molar ratios of reactants were obtained. The purity of the sample and the
specific surface area of synthesized particles were determined. The isoelectric point and
electrokinetic potential of fluorite particles in the suspension with stoichiometric ratio of
reactants and in suspensions with excess of calcium and fluoride ions is determined by
electrophoresis. The kinetics of dissolution at two pH values for synthesized and acquired
fluorite particles have been investigated. It has been shown that the largest fluorite particles are
formed in excess of fluoride ions during the synthesis, while the fastest growth is measured for
synthesis in the suspension with stoichiometric ratio of reactants. The rate of dissolution of
fluorite depends on the pH. The rate coefficients of dissolution of fluorite particles and the order
of the dissolution reaction with respect to hydronium ions were determined.

• Keywords: rast kristala; fluorit; izoelektrična točka; otapanje koloidnih čestica
• Keywords (english): crystal growth; dissolution of colloidal particles; fluorite; isoelectric point
• Language: croatian
• URN:NBN: urn:nbn:hr:217:106373
• 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: HRZZ; Funding stream: IP
• Study programme: Title: Graduate university studies in chemistry; specializations in: Research programme; Course: Research programme; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra kemije (magistar/magistra kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access; Embargo expiration date: 2024-03-29
• Created on: 2022-10-21 09:20:05