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Title:Inhibicijska učinkovitost mešanice škroba in površinsko aktivnih snovi v kislem mediju : diplomsko delo univerzitetnega študijskega programa I. stopnje
Authors:Slapničar, Špela (Author)
Fuchs-Godec, Regina (Mentor) More about this mentor... New window
Bren, Urban (Co-mentor)
Files:.pdf UN_Slapnicar_Spela_2019.pdf (2,60 MB)
MD5: BD7783B3091223CBC2277222D10DC041
 
Language:Slovenian
Work type:Bachelor thesis/paper (mb11)
Typology:2.11 - Undergraduate Thesis
Organization:FKKT - Faculty of Chemistry and Chemical Engineering
Abstract:Korozija je proces, ki lahko povzroči veliko materialno škodo, zato so se začeli uporabljati različni premazi, ki lahko material zaščitijo delno ali v celoti. Poleg tega imajo nekateri, običajno najučinkovitejši inhibitorji korozije lastnost negativnega vpliva na okolje, zato zadnja leta potekajo raziskave o okolju prijaznih inhibitorjih. V diplomski nalogi je predstavljen naravni inhibitor korozije, škrob, v mešanici z in brez dodatka površinsko aktivnih snovi. S pomočjo eksperimentalnega dela na vzorcih jekla smo ugotovili, da škrob uspešno deluje kot inhibitor v kislem mediju. Za slednjega se ne sme uporabiti močnih kislin, saj tam škrob zaradi zoglenelosti izgubi inhibicijske lastnosti. Glede na izbran sistem in dobljene rezultate lahko sklepamo, da je primeren kisli medij, šibka raztopina klorovodikove kisline, v našem primeru s koncentracijo 5,0 % (wt.). Pri dodatku 2,0 % škroba v HCl je bila najvišje dosežena vrednost inhibicijske učinkovitosti IE, okoli 50 %. Z zniževanjem koncentracije škroba se je posledično zniževala tudi vrednost IE. Ob sočasnem dodatku škroba in površinsko aktivne snovi CTAB (Cetilamonijev bromid) v izbran korozivni medij, se IE v krajšem časovnem intervalu izpostavitve kovinskega vzorca ni veliko razlikovala od primerov, ko smo dodali le škrob. Pri izpostavitvi vzorca tej mešanici v daljšem časovnem intervalu se je vrednost IE zvišala ter posledično tudi upočasnila hitrost korozijskih procesov. Dodatek kalijevega jodida (KI), škroba in CTAB v 5,0 % vodno raztopino HCl je vrednost IE približala 90 % v vseh izbranih časovnih intervalih. Morfologijo površin testiranih vzorcev smo pregledali še z navadnim svetlobnim mikroskopom ter infrardečo spektroskopijo s Fourierjevo transformacijo na oslabljeni totalni odboj (ATR-FTIR) za potrditev nastale zaščitne plasti na osnovi adsorpcije. Vse ugotovitve potrjujejo, da mešanica škroba, CTAB in kalijevega jodida sinergistično deluje kot dober inhibitor korozijskih procesov v izbranem sistemu. V prihodnosti bi veljalo preskusiti omenjeno mešanico za korozijsko zaščito jekla v večjem obsegu (daljši čas izpostavitve, različne vrste jekel) ali še na drugih kovinskih materialih.
Keywords:škrob, korozija, površinsko aktivne snovi, klorovodikova kislina
Year of publishing:2019
Place of performance:Maribor
Publisher:[Š. Slapničar]
Number of pages:X, 29 str.
Source:Maribor
UDC:628.483(043.2)
COBISS_ID:22683158 New window
NUK URN:URN:SI:UM:DK:OFXNXPU0
Views:399
Downloads:105
Metadata:XML RDF-CHPDL DC-XML DC-RDF
Categories:KTFMB - FKKT
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Licences

License:CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
Link:http://creativecommons.org/licenses/by-nc-nd/4.0/
Description:The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.
Licensing start date:30.08.2019

Secondary language

Language:English
Title:Inhibition effectiveness of starch and surfactants mixture in acidic medium
Abstract:Corrosion is a process that can cause great material damage, therefore, various coatings have been used in order to protect the material partially or fully. Some of them, often the most effective inhibitors of corrosion, have a negative impact on the environment and that is why in the last years various studies about more environmentally friendly inhibitors are being conducted. Starch - a natural inhibitor of corrosion in a mixture with or without surfactants is used in this diploma thesis. We have experimentally worked on samples of steel and determined that starch successfully acts as an inhibitor in acidic medium. Latter must not consist of strong acids, because starch can lose its inhibition properties due to carbonization. Considering the chosen sistem and our results we can conclude that the optimal acidic medium is a weak solution of hydrochloric acid, in our case 5.0%. With the additon of 2.0% starch in HCl the highest achieved value of inhibiton effectiveness IE was around 50%. Decreasing of the starch concentration resulted in the decreasing of the IE value as well. With the addition of starch and surfactant CTAB (Cetrimonium bromide) to the acid the IE did not differ from the samples where we added just starch over a short period of time. However the exposure of the sample to the mixture for a longer time interval resulted in increased IE meaning the corrosion processes were slowed down. The addition of potassium iodide (KI), starch and CTAB to 5.0% HCl water solution resulted in increasing of IE to near 90% in all chosen time intervals. The surface morphology of tested samples was inspected with a regular light microscope and attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) to confirm the formation of the protective layer on the basis of adsorption. All findings confirm that starch, CTAB and potassium iodide act sinergistically in a mixture as a good inhibitior of corrosion procceses for a chosen system. In the future the mentioned mixture should be tested for corrosion protection of steel in a larger extent or on other metallic materials.
Keywords:starch, corrosion, surfactants, hydrochloric acid


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