Volna kot učinkovit sorbent za odstranjevanje težkih kovin iz odpadne vode

magistrsko delo

Nina Šenekar (Avtor), Marjana Simonič (Mentor), Lidija Fras Zemljič (Komentor)

Povzetek

Namen magistrske naloge je bil pridobiti visoko učinkovit sorbent za odstranjevanje Zn(II) iz odpadnih vod. Izvedli smo fizikalno in kemijsko modifikacijo volne s hitozanom; slednja je potekla z nastankom amidne vezi ob dodatku zamreževalcev EDC in NHS v razmerju 2 : 1. Prisotnost funkcionalnih skupin smo preverili s FT-IR spektri. Uspešnost modifikacije smo določili s potenciometrično ter polielektrolitsko titracijo. Osrednji del študije je bila sorpcija Zn(II) na razmaščeno in modificirano volno. Preučili smo vpliv kontaktnega časa, pH, koncentracije kovinskih ionov in temperature na sorpcijski proces. Preverili smo kinetiko psevdo-prvega in psevdo-drugega reda, prileganje Langmuirjevemu in Freundlichovemu modelu ter določili termodinamiko procesa. Desorpcijo Zn(II) z Na2-EDTA smo izvedli v štirih zaporednih ciklih in ji določili kinetiko. Sorbent z najvišjo koncentracijo protoniranih amino skupin (607,7 mmol kg-1) in sorpcijsko kapaciteto (1,52 mg g-1) smo pridobili z volno, fizikalno modificirano z nanosom 1 % (m/V) makromolekularne raztopine hitozana in poskusi sorpcije pri pH = 5. Z raztopino Zn(II) začetne koncentracije 12,5 mg l-1, kontaktnim časom 24 h in T = 25 °C smo dosegli 98,19 % učinkovitost sorpcije Zn(II). Časovni profil sorpcije Zn(II) z razmaščenimi in modificiranimi vlakni je ustrezal kinetiki psevdo-drugega reda (R2 > 0,9984). Najvišje prileganje eksperimentalnih podatkov smo dosegli z Langmuirjevim modelom (R2 > 0,9866). Proces sorpcije Zn(II) je bil spontan (∆G° < 0) in eksotermen (∆H° < 0). Desorpcijo Zn(II) v štirih ciklih smo uspešno izvedli z razmaščeno volno. Desorpcija Zn(II) s površine fizikalno in kemijsko modificirane volne je s cikli naraščala.

Ključne besede

volna;hitozan;cink;graftanje;FT-IR;potenciometrična titracija;polielektrolitska titracija;biosorpcija;desorpcija;magistrske naloge;

Podatki

Jezik:	Slovenski jezik
Leto izida:	2019
Tipologija:	2.09 - Magistrsko delo
Organizacija:	UM FKKT - Fakulteta za kemijo in kemijsko tehnologijo
Založnik:	[N. Šenekar]
UDK:	66.81.5:628.179.2(043.2)
COBISS:	22736406
Št. ogledov:	913
Št. prenosov:	177
Ocena:	0 (0 glasov)
Metapodatki:

Ostali podatki

Sekundarni jezik:	Angleški jezik
Sekundarni naslov:	Wool as an efficient sorbent for the removal of heavy metals from waste water
Sekundarni povzetek:	The purpose of the master`s thesis was to obtain a highly efficient sorbent for the removal of Zn(II) from waste water. The physical and chemical modification of chitosan onto wool was performed; the latter was due to formation of an amide bond with the addition of EDC and NHS crosslinkers (2 : 1). The presence of functional groups was verified by FT-IR spectra. Effective binding of chitosan onto wool was determined by potentiometric and polyelectrolyte titration. The main part of the thesis was the sorption of Zn(II) onto degreased and modified wool. The effect of contact time, pH, metal ion concentration and temperature on the sorption process was studied. We determined the kinetics parameters of pseudo-first and pseudo-second order, fitting the Langmuir and Freundlich model and thermodynamics of the process. Desorption of the Zn(II) with Na2-EDTA was performed in four consecutive cycles. We determined kinetics of desorption. The sorbent with the highest concentration of protonated amino groups (607,7 mmol kg-1) and sorption capacity (1,52 mg g-1) was obtained with wool, physically modified by applying 1 % (m/V) macromolecular chitosan solution at pH = 5. With the initial concentration of 12,5 mg g-1, contact time of 24 h, pH = 5 and T = 25 °C resulted in 98,19 % efficiency. Sorption of Zn(II) with degreased and modified wool corresponded to pseudo-second order kinetics (R2 > 0,9884). Langmuir model was found to be more suitable (R2 > 0,9866) in comparison to Freundlich model. The Zn(II) sorption process was spontaneous (∆G° < 0) and exothermic (∆H° < 0). Desorption of Zn(II) in four cycles was successfully carried out with degreased wool. The desorption of Zn(II) from the surface of physically and chemically modified wool increased with cycles.
Sekundarne ključne besede:	wool;chitosan;zinc;grafting;FT-IR;potentiometric titration;polyelectrolyte titration;biosorption;desorption;
Vrsta dela (COBISS):	Magistrsko delo/naloga
Komentar na gradivo:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Strani:	XII, 61 str.
ID:	11233913