Identifikacija kristaliničnih snovi v trdnih čistilnih sredstvih z rentgensko praškovno difrakcijo

Ruklić, Sara (author), Počkaj, Marta (mentor)

Uporaba tablet za pomivalni stroj in abrazivnih čistil zadnje časa narašča, saj se način življenja močno spreminja in ljudje nimamo več časa za pranje posode na roke ali pa za čakanje, da madež odpusti, da ga lahko odstranimo. Zato sem se odločila, da analiziram sestavo različnih tablet za pomivalne stroje in abrazivnih čistilnih sredstev z metodo praškovne difrakcije. Zanimalo me je, v kolikšni meri se bodo dobljeni rezultati ujemali z na izdelkih navedenimi deklaracijami. Rentgenska praškovna difrakcija je tehnika karakterizacije kristaliničnih snovi. Postopek poteka tako, da vzorec obsevamo rentgensko svetlobo določene valovne dolžine. Ta se na vzorcu uklanja, nastale uklone pa zabeleži elektronski detektor. Po končanem snemanju uklonske slike dobimo difraktograme, ki jih lahko s pomočjo različnih računalniških programov, kot je npr. X’Pert HighScore Plus, primerjamo med seboj. Prav tako pa lahko na osnovi izmerjenih difraktogramov in primerjave s PDF-zbirko difraktogramov standardov z ustreznim računalniškim programom (kot je npr. Crystallographica Search-Match) ugotovimo, katere trdnine so prisotne v obravnavanih vzorcih. Z analizo sem ugotovila, da imajo abrazivna čistila najpogosteje za glavno sestavino kalcijev karbonat. Pri preučevanju tablet za pomivalni stroj pa sem ugotovila, da je sestava različnih izdelkov zelo podobna, saj imajo veliko skupnih sestavin. Največkrat so se pojavile naslednje kristalinične trdnine: natrijev karbonat, natrijev hidrogenkarbonat, natrijev citrat dihidrat, trinatrijev hidrogenkarbonat dihidrat in natrijev perkarbonat. Pri tabletah, ki smo jih razdelili na sredico in zunanji del, sem ugotovila, da se sestava obeh delov razlikuje. Zato lahko predvidevam, da se razlikujeta tudi njuni funkciji pri pranju posode v pomivalnem stroju. Deklaracije so na tabletah za pomivalni stroj so v večini primerov napisane pomanjkljivo oziroma niso skladne z rezultati, dobljenimi na osnovi identifikacije s praškovno difrakcijo.

• Language: Slovenian
• Keywords: rentgenska praškovna difrakcija, difraktogram, abrazivna čistila, tablete za pomivalni stroj
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2021
• PID: 20.500.12556/RUL-129013
• COBISS.SI-ID: 75129603
• Publication date in RUL: 23.08.2021

Secondary language

• Language: English
• Title: Identification of crystalline phases in solid cleaning agents by means of X-ray powder diffraction

Abstract

The use of household cleaning agents and abrasive cleaners is currently growing, mainly due to the changing lifestyle, as people do not have time to wash the dishes by hands anymore. Sometimes even soaking the stains takes too much time. Therefore, I decided to analyse and compare the composition of different cleaning agents by using powder diffraction method. The thesis also contains differences between our results and the products already listed in the declaration. X-ray powder diffraction is a technique used to characterize crystalline substances. The sample is exposed to radiation with X-rays of a certain wavelength. The light interacts with the sample and sends the diffractions of light into the electronic detector. When the procedure is over, powder patterns are obtained which can then be compared with each other by the use of an appropriate computer programme (e. g. X’Pert HighScore Plus). On the basis of comparison between the measured powder patterns with those collected in PDF database by means of a suitable programme (e. g.Crystallographica Search- Match) it can be identified which solids are present in the samples under study. The analyses of the samples have shown that the abrasive cleaners most often contain calcium carbonate as the main ingredient. However, in the case of dishwasher tabs it was found out that the composition of different products is very similar and that they have many ingredients in common. Sodium carbonate, sodium hydrogen carbonate, sodium citrate dehydrate trinatrijev hidrogenkarbonat dihidrat and sodium percarbonate are most commonly present. With the tablets, which were divided into two parts, i. e. core and outer part, a difference in the composition of both parts was noticed. Therefore, it can be predicted that also the functions of both parts differ during the washing process in the dishwasher. In most cases product labels on the dishwasher tablets contain deficient information or do not correspond to the results obtained on the basis of identification by powder diffraction.

• Keywords: X-ray Powder Diffraction, powder diffraction, abrasive cleaners, dishwasher tablets