KINETIKA REAKCIJE BARVILA KRISTAL VIJOLIČNO Z NATRIJEVIM HIDROKSIDOM

Šerbinek, Lea

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Title:	KINETIKA REAKCIJE BARVILA KRISTAL VIJOLIČNO Z NATRIJEVIM HIDROKSIDOM
Authors:	ID Šerbinek, Lea (Author) ID Petek, Aljana (Mentor) More about this mentor... ID Brodnjak Vončina, Darinka (Comentor)
Files:	UNI_Serbinek_Lea_2012.pdf (1,41 MB) MD5: EC6BC79F508342E4F20206B91D231FB4 PID: 20.500.12556/dkum/55aca2a4-cc5e-4dc2-8b80-13b0266a4a6a
Language:	Slovenian
Work type:	Undergraduate thesis
Typology:	2.11 - Undergraduate Thesis
Organization:	FNM - Faculty of Natural Sciences and Mathematics
Abstract:	Eksperimentalno delo je potekalo v mesecu marcu 2012 v laboratoriju za fizikalno kemijo in laboratoriju za analizno kemijo na Fakulteti za kemijo in kemijsko tehnologijo v Mariboru. Določali smo kinetiko reakcije barvila kristal vijolično z natrijevim hidroksidom. Barvilo kristal vijolično (CV+) sodi med trifenilmetanska barvila in se največ uporablja v tekstilstvu za barvanje tkanin, kjer pride tudi do obarvanja odpadnih vod. Razbarvanje omogoča reakcija barvila z natrijevim hidroksidom (NaOH), kjer iz obarvane kationske oblike (CV+) nastane brezbarvna molekularna oblika (CVOH). Hitrost reakcije smo spremljali spektrofotometrično z UV-VIS spektrofotometrom Cary 1 Varian. Pri valovni dolžini 590 nm smo merili zmanjševanje absorbance raztopin v odvisnosti od časa in s pomočjo umeritvene krivulje izračunali spreminjanje koncentracije barvila med reakcijo. Reakcije so potekale pri različnih začetnih koncentracijah NaOH, ki so bile mnogo večje od začetnih koncentracij CV+, kar zagotavlja pogoje psevdo reda. Odvisnost hitrosti reakcije od koncentracije kristal vijoličnega smo določili po metodi začetnih hitrosti in grafično iz ln [CV+] v odvisnosti od časa ter dobili prvi red. Red reakcije glede na natrijev hidroksid je prav tako prvi, medtem ko je celokupni red reakcije drugi. Konstanto hitrosti reakcije smo izračunali iz razmerja konstante hitrosti reakcije psevdo-prvega reda in odgovarjajoče začetne koncentracije natrijevega hidroksida. Povprečna vrednost 30-ih konstant je (0,12 ± 0,01) L mol-1 s-1.
Keywords:	barvilo kristal vijolično, baza natrijev hidroksid, UV-VIS spektrofotometer Cary 1 Varian, kemijska kinetika, spektrofotometrija, absorbanca
Place of publishing:	Maribor
Publisher:	[L. Šerbinek]
Year of publishing:	2012
PID:	20.500.12556/DKUM-37417
UDC:	544(043.2)
COBISS.SI-ID:	19365896
NUK URN:	URN:SI:UM:DK:068EPRH8
Publication date in DKUM:	27.09.2012
Views:	3422
Downloads:	194
Metadata:
Categories:	FNM
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Secondary language

Language:	English
Title:	Reaction kinetics of crystal violet dye with sodium hydroxide
Abstract:	Experimental work was carried out in March 2012, at the Faculty of Chemistry and Chemical Engineering in Maribor, at the Laboratory for Physical Chemistry, and Laboratory for Analytical Chemistry. We tried to determine the kinetics of the reaction between crystal violet dye and sodium hydroxide. The crystal violet dye (CV+) belongs to triphenylmethane dyes and is mostly used for colouring fabrics in textile industry, that also causes colouration of waste waters. Reaction of the dye with sodium hydroxide (NaOH) causes decolouration, where the coloured cationic form (CV+) changes into an uncoloured molecular form (CVOH). The reaction rate was monitored spectrophotometrically, with UV-VIS spectrophotometer Cary 1 Varian. At wavelength of 590 nm we measured the decreasing of the solutions’ absorbance, depending on time. Then, with the help of calibration curve we calculated the decreasing of the dye concentration during the reaction. The reactions were carried out with various concentrations of NaOH which were far greater that the initial concentrations of CV+, that assured the conditions of pseudo-order. Reaction rate dependence on the crystal violet concentration was determined with the method of initial rates, and also graphically from ln [CV+] versus time. In this way, we obtained the first-order regarding CV. The reaction order with respect to the sodium hydroxide is also the first, while the overall order of the reaction is second. The reaction rate constant was calculated from the ratio between the reaction rate constant of the pseudofirst-order and corresponding initial concentration of sodium hydroxide. An average value of thirty constants was (0.12 ± 0.01) L mol-1 s-1.
Keywords:	crystal violet dye, sodium hydroxide base, UV-VIS spectrophotometer Cary1Varian, chemical kinetics, spectrophotometry, absorbance

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