University of Split Repository
Not a member yet
29028 research outputs found
Sort by
Removal of carbendazim from aqueous solution by sorption on different low-cost sorbents : diploma thesis
No full textU današnje vrijeme, razvijena poljoprivredna proizvodnja predstavlja veliki ekološki problem zbog značajne uporabe pesticida koji ispiranjem iz tla mogu dospjeti u vodne ekosustave. Zbog štetnog djelovanja na žive organizme i ljudsko zdravlje, ostatke pesticida je nužno ukloniti iz voda. Stoga je u ovom radu ispitana mogućnost pročišćavanja vode onečišćene fungicidom karbendazimom (c o =0,992 mg/L) sorpcijom na različitim low-cost sorbensima – prirodnom zeolitu klinoptilolitu, njegovom modificiranom natrijevom obliku, željezovom obliku te sumporom impregniranom obliku, kao i nusproizvodima prerade voća – košticama maslina, trešanja i višanja. Pri danim eksperimentalnim uvjetima, najveći kapacitet (0,064 mg/g) pokazao je natrijev oblik prirodnog zeolita s učinkovitošću uklanjanja od 64,42 %. Međutim, ostatne koncentracije karbendazima bile su u rasponu od 0,353 mg/L do 0,933 mg/L, što je iznad dopuštenih graničnih vrijednosti od 0,5 µg/L za ukupne te 0,1 µg/L za pojedinačne pesticide u vodi za ljudsku potrošnju. Stoga, kako bi se postigla zadovoljavajuća obrada pesticidima onečišćenih voda, buduća istraživanja treba usmjeriti na odgovarajuću modifikaciju postojećih materijala kao i na kombinaciju više metoda obrade, uključujući adsorpciju, napredne oksidacijske procese ili membranske tehnike.Nowadays, developed agricultural production represents a significant ecological problem due to the extensive use of pesticides, which can leach from soil into aquatic ecosystems. Due to their harmful effects on living organisms and human health, it is necessary to remove pesticide residues from water. Therefore, this study examined the treatment of water contaminated with the fungicide carbendazim (c o =0.992 mg/L) through sorption on various low-cost sorbents – natural zeolite clinoptilolite, its modified sodium form, iron form, and sulphur-impregnated form, as well as fruit processing by-products – olive, cherry, and sour cherry pits. Under the given experimental conditions, the sodium form of natural zeolite showed the highest capacity (0.064 mg/g) with a removal efficiency of 64.42%. However, the residual concentrations of carbendazim ranged from 0.353 mg/L to 0.933 mg/L, which is above the permissible limit values of 0.5 µg/L for total and 0.1 µg/L for individual pesticides in water for human consumption. Therefore, in order to achieve a satisfactory treatment of pesticide-contaminated water, future research should be focused on the appropriate modification of existing materials as well as a combination of several treatment methods, including adsorption, advanced oxidation processes or membrane techniques
Analysis of hybrid process of electrocoagulation with aluminium electrodes, zeolite and ultrasound : bachelor thesis
No full textBudući su otpadne vode iz procesa kompostiranja složenog sastava, sve je veća potreba za razvojem hibridnih procesa njihove obrade. U ovom radu provedeno je ispitivanje hibridnih procesa obrade na bazi elektrokoagulacije sa aluminijevim elektrodama, zeolitom i ultrazvukom. Uspoređeni su hibridni procesi elektrokoagulacije sa sintetskim zeolitom te hibridni procesi elektrokoagulacije sa sintetskim zeolitom i ultrazvukom provedeni simultano i dvostupanjski. Analiza učinkovitosti hibridnih procesa provedena je temeljem usporedbe fizikalno-kemijskih pokazatelja praćenih u otopinama, promjene mase anoda i katoda te testa taloživosti suspenzije. Rezultati su pokazali da je hibridni proces elektrokoagulacije sa zeolitom najbolji izbor za obradu otpadne kompostne vode s obzirom na najveće smanjenje kemijske potrošnje kisika (KPK) i mutnoće te dobro taloženje flokula. Međutim, budući je povećana potrošnja elektroda, ekonomičniji odabir bi bio simultano provođenje elektrokoagulacije uz dodatak zeolita i ultrazvuka.As the wastewater from the composting process has a complex composition, there is an increasing need to develop hybrid processes for its treatment. In this work, different hybrid processes based on electrocoagulation with aluminum electrodes, zeolite and ultrasound were investigated. A comparison was made between the hybrid processes of electrocoagulation with synthetic zeolite and the hybrid processes of electrocoagulation with synthetic zeolite and ultrasound, carried out simultaneously and in two stages. The effectiveness of the hybrid processes was analyzed on the basis of the comparison of the physical and chemical indicators monitored in the solutions, the change in the mass of the anodes and cathodes and the suspension settling test. The results showed that the hybrid process of electrocoagulation with zeolite is the best choice for the treatment of compost wastewater, as it reduces the chemical oxygen demand (COD) and turbidity and produces good floc settling. However, as the consumption of electrodes has increased for economic reasons, simultaneous electrocoagulation with zeolite and ultrasound would be a better choice
Effect of grinding techniques on the microstructure and powder characterization of purslane (Portulaca oleracea L.) and phenolic content in water extract before and after in vitro simulated digestion : bachelor thesis
No full textTušt (Portulaca oleracea L.) je biljka prepoznata kao vrijedan izvor hranjivih tvari i bioaktivnih spojeva, poput omega-3 masnih kiselina, antioksidansa, vitamina i minerala. Unatoč tradicionalnoj percepciji kao korova, tušt ima visoku nutritivnu vrijednost i široku primjenu u prehrani. Ovaj rad istražuje proizvodnju praha od liofiliziranog tušta koji zadržava hranjive tvari te se koristi kao dodatak prehrani. Fokus je na ispitivanju razlika u mikrostrukturi prahova dobivenih različitim tehnikama mljevenja (mlin s noževima, kuglični mlin, planetarni mlin), analizi raspodjele veličina čestica, nasipne gustoće i parametara boje te udjela i sastava fenola prije i poslije simuliranog procesa probave. Rezultati su pokazali da različite tehnike mljevenja značajno utječu na mikrostrukturu, veličinu čestica i stabilnost bioaktivnih spojeva, s kugličnim mljevenjem kao najpovoljnijim za očuvanje fenola. Granulometrijska analiza otkrila je najveću zastupljenost čestica veličine 200 µm nakon mljevenja mlinom s noževima i kugličnim mlinom, dok su kod planetarnog mlina prevladavale čestice iznad 200 µm. Nasipna gustoća praha bila je najviša kod mljevenja kugličnom mlinom što je ujedno doprinijelo svojstvima tečenja. Analiza boje pokazala je da je prah nakon mljevenja planetarnim mlinom imao najtamniju boju zbog oksidacije materijala, dok je mljevenje kugličnim mlinom najmanje utjecalo na promjenu boje. Nakon simulirane probave, fenolni spojevi su pokazali visoku stabilnost, osobito nakon želučane faze probave, dok je stabilnost opadala nakon crijevne faze. Mljevenje kugličnim mlinom dalo je najbolje rezultate u očuvanju fenola nakon obje faze probave, dok su nesamljeveni uzorci imali najveću biodostupnost fenolnih spojeva. Ovi rezultati ukazuju na značajan potencijal tušta kao funkcionalne hrane i dodatka prehrani, posebice u obliku praha, te na važnost optimizacije tehnika mljevenja i skladištenja kako bi se očuvale hranjive i bioaktivne komponente.Purslane (Portulaca oleracea L.) is a plant recognized as a valuable source of nutrients and bioactive compounds, such as omega-3 fatty acids, antioxidants, vitamins, and minerals. Although traditionally perceived as a weed, purslane has high nutritional value and is widely used in food. This paper investigates the production of powder from lyophilized purslane, which retains its nutrients and is used as a dietary supplement. The focus is on examining the differences in the microstructure of powders obtained using different milling techniques (blade mill, ball mill, planetary mill), analyzing particle size, bulk density, color parameters, and the content and composition of phenols before and after a simulated digestion process. The results showed that different milling techniques significantly affect the microstructure, particle size, and stability of bioactive compounds, with ball milling being the most favorable for phenol preservation. Granulometric analysis revealed the largest representation of 200 µm particles after milling with blade and ball mills, while particles larger than 200 µm dominated after milling with the planetary mill. The bulk density of the powder was highest with ball milling, which also contributed to flow properties. Color analysis showed that powder after planetary milling had the darkest color due to material oxidation, while ball milling had the least impact on color retention. After simulated digestion, phenolic compounds showed high stability, particularly after the gastric digestion phase, while stability decreased after the intestinal phase. Ball milling gave the best results for phenol preservation after both phases of digestion, while unmilled samples had the highest bioavailability of phenolic compounds. These results highlight the significant potential of purslane as a functional food and dietary supplement, especially in powder form, and the importance of optimizing milling and storage techniques to preserve its nutritional and bioactive components
Life-cycle assessment of municipal waste management systems in Croatia's leading tourist towns : diploma thesis
No full textHrvatska, popularno turističko odredište, imala je visoku sezonalnost turizma između 2015. i 2021., što je doprinijelo povećanju komunalnog otpada u hrvatskim turističkim gradovima. U ovom radu analizirane su količine komunalnog otpada u pet vodećih hrvatskih turističkih gradova od 2015. do 2021., tj. u Zagrebu, Poreču, Rovinju, Splitu i Dubrovniku te je uočeno da količina prikupljenog komunalnog otpada varira u skladu s promjenom turističkog ekvivalenta stanovništva (TES). Navedeno je izraženije u gradovima s većim vrijednostima TES-a, poput Poreča, Rovinja i Dubrovnika. Također, analiziran je utjecaj na okoliš sustava gospodarenja krutim komunalnim otpadom navedenih gradova u godini s najvećim brojem ostvarenih noćenja turista, tj. u 2019. godini, računalnim programom IWM-EPIC/CSR procjene životnog ciklusa (engl. life-cycle assessment). LCA je pokazala da su sustavi gospodarenja otpadom u Poreču i Rovinju imali manji negativan utjecaj na okoliš u 2019. od onih u većim gradovima poput Zagreba, Splita i Dubrovnika.Croatia, a popular tourist destination, has a high seasonality between 2015 and 2021, which results in increasing municipal waste in Croatian tourist towns. This paper analyzes municipal waste in five major Croatian tourist towns (Zagreb, Poreč, Rovinj, Split, and Dubrovnik) from 2015 to 2021., revealing that the amount of collected municipal waste varies in tandem with the change in tourist population equivalent (TES). This is more prominent in towns with higher TES values, such as Poreč, Rovinj, and Dubrovnik. In addition, the IWM-EPIC/CSR life-cycle assessment software was used to examine the environmental impact of the indicated cities' solid municipal waste management systems in the year with the highest number of tourist overnight stays, namely 2019. The LCA showed that waste management systems in Poreč and Rovinj had a lower negative impact on the environment in 2019 than those in larger towns like Zagreb, Split, and Dubrovnik
Application of steel electrodes in the treatment of compost wastewater by the combined process of electrocagulation, zeolite and magnet : diploma thesis
No full textU ovom radu je ispitan utjecaj NdFeB magneta na proces elektrokoagulacije u kombinaciji sa zeolitom u cilju pročišćavanja otpadne vode. Korišten je stakleni elektrokemijski reaktor s elektrodama od ugljičnog čelika pri čemu je NdFeB magnet bio smješten ispod reaktora. Ispitivanja su provedena u vremenskom periodu od 10 do 30 minuta, bez i s podešavanjem pH vrijednosti na pH = 3,72, pri čemu su mjereni parametri kao što su promjena pH vrijednosti i temperature otopine s vremenom, promjena mase elektroda, napon i sposobnost taloženja suspenzije. Rezultati su pokazali da postupak elektrokoagulacije s magnetom dovodi do nešto većeg porasta pH otopine i nešto manjeg porasta temperature u usporedbi s elektrokoagulacijskim postupkom. Primijećeno je smanjenje kemijske potrošnje kisika (KPK) za 84.08- 91.00% nakon 30 minuta provedbe eksperimenta, bez vidljivog utjecaja magneta na ove vrijednosti. Nešto veća oštećenja površine elektroda su vidljiva kod upotrebe magneta pri čemu se najveće promjene uočavaju kod mjerenja od 20 minuta. Smanjenje mase anode raste s vremenom provođenja eksperimenta, a uočena je i mala promjena mase katode. Oba hibridna postupka omogućuju 80-100% regeneracije mase zeolita. Manja potrošnja energije (niže vrijednosti napona i snage) su potrebne kod postupaka koji su provedeni korištenjem magneta u odnosu na eksperimente bez magneta. Pozitivan utjecaj magneta na taloženje zamijećen je u eksperimentu s vremenom kontakta od 20 minuta.In this work, the influence of the NdFeB magnet on the electrocoagulation process in combination with zeolite for wastewater treatment is investigated. An electrochemical glass reactor with carbon steel electrodes was used, under which a NdFeB magnet was attached. The tests were carried out over a period of 10 to 30 minutes, without and with the pH adjusted to pH = 3.72, measuring parameters such as the change in pH and temperature of the solution over time, the change in the mass of the electrode, the voltage and the ability to settle the suspension. The results showed that the electrocoagulation method with a magnet led to a slightly higher increase in the pH of the solution and a slightly lower increase in temperature compared to the electrocoagulation method. After 30 minutes of the experiment, a decrease in chemical oxygen demand (COD) of 84.08-91.00% was observed without the magnet having a visible effect on these values. When a magnet is used, slightly greater damage to the electrode surface is visible, with the most significant changes observed in measurements from 20 minutes onwards. The decrease in the anode's mass increases with the experiment's duration, but a small change can also be observed in the mass of the cathode. Both hybrid processes enable 80-100% regeneration of the zeolite. Procedures carried out with a magnet require less energy consumption (lower voltage and power values) than experiments without a magnet. The positive influence of the magnet on the deposition was observed in the experiment with a contact time of 20 minutes
Impeller type impact on wastewater treatment using the hybrid process of electrocoagulation and zeolite : diploma thesis
No full textU ovom radu provedena su ispitivanja hibridnog procesa obrade otpadne vode elektrokoagulacijom uz dodatak sintetskog zeolita granulacije < 40 µm uz primjenu operacije miješanja korištenjem različitog tipa miješala, odnosno turbinskog tipa miješala s ravnim lopaticama SBT (engl. straight blade turbine) i turbinskog tipa miješala s lopaticama pod nagibom PBT (engl. pitched blade turbine) miješala pri različitim vremenima kontakta od 30, 20 i 10 minuta. Eksperimenti su izvedeni u elektrokemijskoj ćeliji s Al i Fe elektrodama, pri konstantnoj gustoći struje od 0,0182 A/cm 2 , udaljenosti elektroda od 3 cm, dodatkom elektrolita (0,5 g/L) i zeolita (15 g/L). Tijekom eksperimenta pratila se pH vrijednosti, temperatura i električna vodljivost, dok su kemijska potrošnja kisika, mutnoća i ukupni isparni ostatak određeni na početku i na kraju procesa. Nakon provedbe hibridnog procesa ispitane su promjene mase elektroda te je proveden test taloženja suspenzija. Rezultati su pokazali da je za obradu otpadne vode najbolje upotrijebiti elektrokoagulaciju bez dodatka zeolita uz primjenu Fe elektroda te uz primjenu PBT miješala. Izračun operativnih troškova pokazao je da dodatak zeolita i duže vrijeme provedbe procesa pridonosi boljem otapanju elektroda, neovisno o tipu miješala.This study examined a hybrid wastewater treatment process through electrocoagulation using synthetic zeolite with a particle size of < 40 µm by applying mixing operations using different impeller types: SBT (straight blade turbine) and PBT (pitched blade turbine). The experiments involved varying contact times of 30, 20, and 10 minutes. They were conducted in an electrochemical cell with aluminum and iron electrodes, at a constant current density of 0,0182 A/cm², an electrode spacing of 3 cm, and the addition of electrolyte (0,5 g/L) and zeolite (15 g/L). During the experiments pH values, temperature, as well as electrical conductivity were monitored. Chemical oxygen demand, turbidity, and total solids were determined at the beginning and at the end of the process. After the hybrid process was completed, changes in electrode mass and the sedimentation of suspensions were examined. The results indicated that the most effective wastewater treatment was achieved through electrocoagulation without the addition of zeolite, using iron electrodes and PBT impeller. The operational cost calculations showed that the addition of zeolite and longer processing time enhances electrode dissolution, regardless of the impeller type
Removal of Tartrazine Yellow dye from aqueous solution by electrocoagulation : diploma thesis
No full textU radu je promatran je utjecaj gustoće struje (0.008, 0.016 ili 0.024 A/cm 2 ) na učinkovitost uklanjanja Tartrazine Yellow (TY) boje. Vrijeme elektrokoagulacijskog (EK) procesa je variralo u granicama od 10 do 50 min, a početna pH vrijednost onečišćene otopine od 3.0 do 7.0. Tijekom EK procesa dolazi do promjene pH, temperature, električne provodnosti te koncentracije TY boje. Dobiveni rezultati ukazuju na veliku učinkovitost uklanjanja TY boje, koja svih eksperimentalnih uvjeta raste i postiže konstantnu vrijednost. Maksimalna učinkovitost uklanjanja TY boje od 99.39 % postignuta je nakon 37 minuta pri i = 0.024 A/cm 2 i pH vrijednosti 3.0. Tijekom EK procesa sagledavana je potrošnja anodnog materijala koja se povećava s porastom gustoće struje. Izgled anoda nakon provedenog procesa ukazuje na opći oblik korozijskog napada čija intenzivnost ovisi o primijenjenoj struji. Operativni troškova procesa ovise o eksperimentalnim uvjetima te je uočeno da se povećavaju s porastom gustoće struje, a opadaju porastom podešene početne pH vrijednosti TY otopine.In this paper, the current density (0.008, 0.016 or 0.024 A/cm 2 ) on the efficiency of Tartrazine Yellow (TY) dye removal was investigated. The duration of the electrocoagulation (EC) process varied from 10 to 50 minutes and the initial pH of the contaminated solution from 3.0 to 7.0. During the EC process, the pH, temperature, electrical conductivity, and concentration of the TY dye changed. The results show a high efficiency in removing TY dye, which increases and reaches a constant value under all experimental conditions. The maximum TY dye removal efficiency of 99.39% was achieved after 37 minutes at i = 0.024 A/cm 2 and a pH of 3.0. During the EC process, the consumption of the anode material was observed to increase with the increase in current density. The appearance of the anodes after the process indicates a general form of corrosion attack, the intensity of which depends on the applied current. The operating costs of the process depend on the experimental conditions and were observed to increase with the increase in current density and decrease with the increase in the adjusted initial pH of the TY solution
Sorption of copper on NaX and Saccharomyces cerevisiae yeast incorporated in alginate : diploma thesis
No full textU ovom radu ispitivala se ravnoteža sorpcije bakrovih iona na zeolitu NaX čestica srednjeg promjera manjeg od 40 µm te suhom pekarskom kvascu Saccharomyces cerevisiae čestica srednjeg promjera manjeg od 160 µm ugrađenima u alginat. Eksperiment se proveo korištenjem suspenzija zeolita NaX, odnosno suhog pekarskog kvasca Saccharomyces cerevisiae imobiliziranih u alginatu i otopine bakrovog(II) klorida dihidrata različitih početnih koncentracija. Pripremljene suspenzije smještene su u vodenu kupelj s trešnjom pri izotermnim uvjetima (T = 27 °C) i brzini od 200 okr./min. Suspenzije su uzorkovane, filtrirane, a filtrati analizirani UV/Vis spektrofotometrom u određenim vremenskim intervalima tijekom 72 sata kako bi se pratilo uspostavljanje ravnoteže u ispitivanom sustavu. Dobiveni eksperimentalni podatci analizirani su Freundlichovom, Langmuirovom, Redlich-Petersonovom i Sipsovom izotermom. Grafičko slaganje dobivenih eksperimentalnih podataka s adsorpcijskim izotermama te vrijednosti izračunatog RMSE i hi-kvadrat testa pokazali su da Langmuirova izoterma najbolje opisuje proces sorpcije bakrovih iona na zeolitu NaX ugrađenom u alginat i proces sorpcije bakrovih iona na pekarskom kvascu Saccharomyces cerevisiae ugrađenima u alginat. Učinkovitost sorpcije smanjuje se porastom početne koncentracije otopine bakrovog(II) klorida dihidrata, a ravnotežno stanje u svim suspenzijama postignuto je nakon 24 sata. Količina bakrovih iona vezanih u ravnoteži ovisna je o početnim koncentracijama otopina; uočava se kako porast početne koncentracije otopine bakrovih iona uglavnom dovodi do rasta količine bakrovih iona vezanih na zeolitu NaX i pekarskom kvascu Saccharomyces cerevisiae ugrađenima u alginat.In this thesis, the equilibrium of copper ion sorption on zeolite NaX, with a mean particles diameter of less than 40 µm, and on dry baker’s yeast Saccharomyces cerevisiae with a mean particles diameter of less than 160 µm incorporated in alginate was investigated. The experiments were carried out using suspension of zeolite NaX, respectively dry baker's yeast Saccharomyces cerevisiae incorporated in alginate and copper(II) chloride dihydrate solution with different initial concentrations. The prepared suspensions were placed in a water bath shaker under isothermal conditions (T = 27 °C) and at a speed of 200 rpm. The suspensions were sampled, filtered, and filtrates were analysed at specific time intervals over a period of 72 hours using a UV/Vis spectrophotometer to verify the establishment of equilibrium in the system under investigation. The experimental data obtained were analysed using the Freundlich, Langmuir, Redlich-Peterson and Sips isotherms. The graphical fit of the experimental data with the adsorption isotherms and the calculated RMSE and chi-square test parameters showed that the Langmuir isotherm best describes the sorption process of copper ions on NaX zeolite and the sorption process of copper ions on Saccharomyces cerevisiae baker's yeast incorporated in alginate. The sorption efficiency decreases with the increase of the initial concentration of the copper(II) chloride dihydrate solution, the equilibrium state was reached in all suspensions after 24 hours. The amount of copper ions retained at equilibrium depends on the initial concentrations of the solutions. It can be observed that an increase in the initial concentration of the copper ion solution mainly leads to an increase in the amount of copper ions sorbed on zeolite NaX and to the baker's yeast Saccharomyces cerevisiae incorporated in alginate
Thermal analysis of polyethylene oxide composite with addition of the magnesium oxide : diploma thesis
No full textU ovom radu istražen je utjecaj dodatka magnezijeva oksida (MgO) na toplinska svojstva i stabilnost kompozita na bazi poli(etilen-oksida) (PEO). Korištenjem diferencijalne pretražne kalorimetrije (DSC) i termogravimetrijske analize (TGA) ispitane su toplinske karakteristike PEO/MgO kompozita. Dodatak MgO snižava karakteristiĉne toplinske prijelaze PEO kompozita, ukljuĉujući temperaturu staklastog prijelaza (T g ), zbog smanjenja kristalnosti. TakoĊer, pogoršava toplinsku stabilnost PEO u kompozitu jer snižava temperaturu poĉetka razgradnje kompozita.This paper investigates the effect of magnesium oxide (MgO) addition on the thermal properties and stability of poly(ethylene oxide) (PEO)-based composites. The thermal characteristics of PEO/MgO composites were examined using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The addition of MgO reduces the characteristic thermal transitions of the PEO composite, including the glass transition temperature (T g ), due to the reduction in crystallinity. Furthermore, it worsens the thermal stability of the PEO composite by lowering the decomposition onset temperature
Testing the stability of fluoride solutions of different concentrations in glass packaging : diploma thesis
No full textStaklo je jedan od najvažnijih materijala u svakodnevnom životu, u kojem se pojavljuje posvuda, a razlog zbog kojeg se tako često koristi je njegova kemijska stabilnost. Kemijski je stabilno zbog svoje amorfne strukture odnosno izostanka pravilnog rasporeda atoma. Iako je staklo otporno na mnoge kemikalije, ono nije univerzalno inertno. Zadatak ovog diplomskog rada je bio u određenom vremenskog periodu, u nekoliko staklenih boca pohraniti različite koncentracije standardne otopine natrijevog fluorida, utvrditi utječe li pohrana tih otopina u staklu na promjenu koncentracije fluorida, odnosno događa li se interakcija otopine (fluorida) sa staklom. U eksperimentu su pripravljene otopine natrijevog fluorida u rasponu koncentracija 1,0×10 --6 do 1,0×10 -2 mol L -1 . Radnim otopinama u svakom mjerenju izmjeren je potencijal, konstruiran je graf ovisnosti potencijala o pF-vrijednosti koncentracija i metodom dodatka standarda matematičkim modelom određena koncentracija. Na temelju eksperimentalnih podataka doneseni su određeni zaključci. Najmanje odstupanje od očekivane koncentracije ispitivanih otopina zabilježeno je u otopini koncentracije 1,0×10 -2 mol L -1 , dok je najveće odstupanje zabilježeno u otopini koncentracije 1,0×10 -3 mol L -1 . Koncentracija otopine 1×10 -5 mol L - 1 je bila nešto malo viša u odnosu na očekivanu vrijednost kroz sva mjerenja. U nastavku eksperimenta uočeno je kako se prvotno izmjerene koncentracije previše ne mijenjaju, pri tome blago rastu ili padaju ali variraju oko početno izmjerenih vrijednosti. Iz grafičkog prikaza ovisnosti pF vrijednosti o danima mjerenja, kao i iz ovisnosti nagiba o danima mjerenja zaključeno je kako se koncentracije, iako u pojedinačnim mjerenjima blago rastu ili padaju, u konačnici ipak ne mijenjaju drastično što ukazuju i navedeni grafički prikazi iz kojih se vidi da su rezultati smješteni uglavnom linearno. Obzirom na to da se ni pri jednoj koncentraciji ne uočava kontinuirani pad vrijednosti kroz cijeli period mjerenja, zaključuje se da u ovom eksperimentu staklo ne utječe na koncentraciju fluorida.Glass is one of the most important materials in everyday life, in which it appears everywhere, and the reason it is used so often is its chemical stability. It is chemically stable due to its amorphous structure, i.e. the absence of a regular arrangement of atoms. Although glass is resistant to many chemicals, it is not universally inert. The task of this thesis was to store different concentrations of a standard solution of sodium fluoride in several glass bottles for a certain period of time, to determine whether the storage of these solutions in glass affects the change in fluoride concentration, or whether the solution (fluoride) interacts with the glass. In the experiment, sodium fluoride solutions were prepared in the concentration range of 1,0×10 -6 to 1,0×10 -2 mol L -1 . The potential was measured with the working solutions in each measurement, a graph of the dependence of the potential on the pF-value of the concentrations was constructed, and the concentration was determined using the standard addition method using a mathematical model. Based on the experimental data, certain conclusions were drawn. The smallest deviation from the expected concentration of the tested solutions was recorded in a solution with a concentration of 1,0×10 -2 mol L -1 , while the largest deviation was recorded in a solution with a concentration of 1,0×10 -3 mol L -1 . The concentration of the solution 1,0×10 -5 mol L -1 was slightly higher compared to the expected value throughout all measurements. In the continuation of the experiment, it was observed that the initially measured concentrations do not change too much, while they rise or fall slightly, but vary around the initially measured values. From the graphical presentation of the dependence of the pF value on the days of measurement, as well as from the dependence of the slope on the days of measurement, it was concluded that the concentrations, although they slightly increase or decrease in individual measurements, ultimately do not change drastically, as indicated by the above graphical representations, which show that the results are arranged mostly linearly. Given that no continuous decrease in values is observed at any concentration throughout the entire measurement period, it is concluded that in this experiment the glass does not affect the fluoride concentration