Kofein kot inhibitor korozijskih procesov v agresivnem mediju

diplomsko delo univerzitetnega študijskega programa I. stopnje

Klara Laura Konda (Author), Regina Fuchs-Godec (Mentor), Urban Bren (Co-mentor)

Abstract

V diplomskem delu je predstavljen kofein kot zeleni inhibitor korozije. Zeleni inhibitorji korozije ali t. i. okolju prijazni inhibitorji korozije so netoksične spojine, ki imajo sposobnost upočasnjevati degradacijo kovin v procesu korozije. Vpliv kofeina na inhibicijo korozije smo preučevali na vzorcih nerjavnega avstenitnega jekla z oznako AISI 304/W.Nr.1.4301, ki so bili izpostavljeni korozijskemu okolju raztopin HCl in H2SO4 različnih koncentracij za različna časovna obdobja (štiri, osem in 24 ur). Pri eksperimentalnem delu smo na vzorcih nerjavnega avstenitnega jekla uporabili naslednje metode: brušenje z vodo brusnim papirjem različnih granulacij, ultrazvočno čiščenje, metodo gravimetrije, mikroskopiranje in analizo z infrardečo spektroskopijo s Fourierjevo transformacijo na oslabljeni totalni odboj (ATR-FTIR). Ugotovljeno je bilo, da 8,5 % raztopina HCl predstavlja ustrezen, še dovolj agresiven medij. V slednjem smo analizirali inhibicijsko učinkovitost kofeina ƞ (%) ob dodatku 1 %, 2 %, 5 % in 10 % masnega deleža kofeina (wk). Izračunali smo korozijsko hitrost r (mm/leto) brez dodanega inhibitorja in z dodanim inhibitorjem. V 8,5 % raztopini HCl smo dosegli najnižjo inhibicijsko učinkovitost kofeina 36,3 % z 1 % dodanega kofeina v času štirih ur in najvišjo inhibicijsko učinkovitost kofeina 69,2 %, z 10 % dodanega kofeina v času osmih ur. Korozijska hitrost v 8,5 % raztopini HCl v primeru dodanega inhibitorja je najvišja pri 1 % dodanega kofeina in znaša 0,80 mm/leto ter najnižja pri 10 % dodanega kofeina in znaša 0,42 mm/leto. Obe hitrosti sta pridobljeni v času osmih ur. Osem ur tako predstavlja prelomen čas, medtem ko 5 % dodanega kofeina predstavlja mejno koncentracijo dodanega inhibitorja.

Keywords

kofein;inhibitor;korozija;agresivni medij;nerjavno jeklo;diplomske naloge;

Data

Language:	Slovenian
Year of publishing:	2020
Typology:	2.11 - Undergraduate Thesis
Organization:	UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher:	[K. L. Konda]
UDC:	620.197.3:663.93(043.2)
COBISS:	33834755
Views:	383
Downloads:	72
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Caffeine as an inhibitor of corrosion processes in aggressive medium
Secondary abstract:	In the diploma thesis, caffeine is evaluated as a green corrosion inhibitor. Green corrosion inhibitors or so-called environmentally-friendly corrosion inhibitors represent non-toxic compounds which can decelerate the metal degradation in the process of corrosion. The caffeine effect on the corrosion inhibition was tested on the samples of stainless austentic steel with the label AISI 304/W.Nr.1.4301 which were exposed to the corrosion environment of HCl and H2SO4 solutions of various concentrations for various time periods (four, eight and twenty four hours). The following methods were used in the experimental part for the samples of stainless austentic steel: abrasion with water sandpapers of various granulations, ultrasonic cleaning, gravimetric analysis, microscopy and the analyses of the attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). It was concluded that 8.5 % HCl solution presents an adequate, sufficiently enough aggressive media. Therefore, the caffeine inhibition efficiency ƞ (%) with the addition of 1 %, 2 %, 5 % and 10 % caffeine mass fraction (wk) was analysed. The corrosion speed r (mm/year) was calculated with and without the added inhibitor. In the 8.5 % HCl solution, the lowest caffeine inhibition efficiency of 36.3 % with 1 % of added caffeine in four hours and the highest caffeine inhibition efficiency of 69.2 % with 10 % of added caffeine in eight hours was achieved. The corrosion speed in the 8.5 % HCl solution is the highest at 1 % of added caffeine and ammounts to 0.80 mm/year and the lowest at 10 % of added caffeine and ammounts to 0.42 mm/year. Both speeds were obtained at eight hours. Eight hours, thus, presents the upheaval time while 5 % of added caffeine presents the concentration limit of the added inhibitor.
Secondary keywords:	caffeine;inhibitor;corrosion;aggressive medium;stainless steel;
Type (COBISS):	Bachelor thesis/paper
Thesis comment:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages:	X, 31 str.
ID:	11993661