Utjecaj pH vrijednosti na spontano taloženje kalcijeva karbonata uz dodatak poli-L-asparginske kiseline ; Kemija u kapljici tvrde vode

master's thesis

• Title (english): Influence of pH on calcium carbonate spontaneous precipitation with the addition of poly-L-aspartic acid ; Chemistry in a drop of hard water
• Author: Iva Vojtkuf
• Mentor: Jasminka Kontrec (mentor)
• Committee member: Jasminka Kontrec (predsjednik povjerenstva)
• Committee member: Draginja Mrvoš-Sermek (član povjerenstva)
• Committee member: Maja Planinić (član povjerenstva)
• Committee member: Nenad Pavin (član povjerenstva)
• Committee member: Davor Kovačević (član povjerenstva)
• Committee member: Katarina Jeličić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Granter: University of Zagreb; Faculty of Science; (Department of Physics); Zagreb
• Defense date and country: 2021-12-02, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry

Abstract

Ovaj rad sastoji se od istraživačkog i metodičkog dijela. U istraživačkom dijelu istražen je proces spontanog taloženja kalcijeva karbonata u prisustvu poli-L-asparaginske kiseline kao modelnog taložnog sustava za istraživanja biomineralizacije u morskim organizmima. Napredovanje procesa taloženja praćeno je potenciometrijski, a talozi karakterizirani infracrvenom spektroskopijom i pretražnom elektronskom mikroskopijom. Svi relevantni početni parametri taložnog sustava (prezasićenost, omjer aktiviteta kalcijevih i karbonatnih iona, temperatura, ionska jakost) bili su konstantni, a promatrani su utjecaji početnog pH (pH0) u rasponu od 8,5 do 10,5 te koncentracije poli-L-asparaginske kiseline. Proces taloženja kalcijeva karbonata je inhibiran u cijelom ispitivanom području pH0 vrijednosti zbog djelovanja poli-L-asparaginske kiseline, a efekt je izraženiji u sinergiji s Mg2+ ionima. U metodičkom dijelu rada pod naslovom Kemija u kapljici tvrde vode načinjen je pregled i kritički osvrt udžbeničke i stručne literature na zadanu temu. Opisana je nastavna jedinica za 90- minutni nastavni sat za učenike četvrtog razreda gimnazije te su predloženi radni listić i uputa za nastavnike temeljena na učenju otkrivanjem.

Abstract (english)

This Diploma thesis consist of two parts: the research part and the methodological part. The research part investigates the process of spontaneous precipitation of calcium carbonate in the presence of poly-L-aspartic acid as a model precipitation system for biomineralization research in marine organisms. The progress of the precipitation process was monitored potentiometrically and the precipitate were characterized by infrared spectroscopy and scanning electron microscopy. All relevant initial parameters of the precipitation system (supersaturation, calcium and carbonate ion activity ratio, temperature, ionic strength) were constant and the influence of the initial pH (pH0) in the range of 8,5 to 10,5 and the concentration of poly-L-aspartic acid were investigated. The process of calcium carbonate precipitation is inhibited in the whole examined range of pH0 values due to the influence of poly-L-aspartic acid, and the effect is more pronounced in synergy with Mg2+ ions. In the methodological part of the Thesis entitled Chemistry in a drop of hard water, critical review of textbooks and professional literature was made. The class for a 90-minute lesson for fourth-grade high school students is described while worksheets and instructions based on discovery learning are proposed to teachers as well.

• Keywords: aragonit; biomineralizacija; kalcijev karbonat; kalcit; poli-L-asparaginska kiselina; spontano taloženje; vaterit; poučavanje kemije; učenje otkrivanjem; karbonatna tvrdoća
• Keywords (english): aragonite; biomineralization; calcium carbonate; calcite; poly-L-aspartic acid; spontaneous precipitation; vaterite; teaching chemistry; discovery learning; carbonate hardness
• Language: croatian
• URN:NBN: urn:nbn:hr:217:502020
• Study programme: Title: Physics and Chemistry; specializations in: Education; Course: Education; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra edukacije fizike i kemije (magistar/magistra edukacije fizike i kemije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2021-12-15 09:03:41