diplomsko delo univerzitetnega študijskega programa I. stopnje
Povzetek
Namen diplomske naloge je preučiti adsorpcijske sposobnosti bentonita za odstranjevanje lipofilnih snovi iz vodnih raztopin.
Vzorec bentonita smo karakterizirali; opravili analizo za določitev elementarne sestave z vrstičnim mikroskopom, izmerili zeta potencial in porazdelitev velikosti delcev. Vrednost zeta potenciala je znašala 0,229 mV. Povprečna velikost delcev je znašala 1833 nm. PDI pa je znašal 0,52.
Učinkovitost adsorpcije smo analizirali gravimetrično. Za ekstrakcijo smo uporabljali n-heksan. Na modelni raztopini sončničnega olja s koncentracijo 6,92 g/L smo ob dodatku 1 g bentonita in stresanju 18 h uspeli odstraniti 98,5 % lipofilnih snovi iz vodne raztopine. Eksperimentalni podatki sledijo Freundlichovi in Langmuirjevi izotermi, vendar je ujemanje večje z Freundlichovo. Zato sklepamo, da je adsorpcija večplastna. Adsorpcijska kapaciteta je znašala 2322 mg/g.
Bentonit smo preizkusili še na realnem vzorcu odpadne vode iz kozmetične industrije. Stresali smo 18 h ob dodatku 1 g bentonita. Učinkovitost adsorpcije je z naraščujočo koncentracijo lipofilnih snovi v vzorcu padala. Pri začetni koncentraciji 446 mg/L smo iz vodne raztopine vzorca uspeli odstraniti 93,0 % lipofilnih snovi. Raztopinam vzorca smo izmerili tudi pH. Ta je znašal ~7.1 in je s koncentracijo rahlo naraščal.
Izrabljeni bentonit smo poskusili regenerirati z 0,1 M razt. NaOH. Regenerirali smo 4 h. Postopek smo ponovili skupno štirikrat. Učinkovitost adsorpcije je že po prvi regeneraciji precej padla, po nadaljnih ponovitvah pa ni padala. Podaljšanje časa regeneracije na 18 h ni imelo vpliva. Dvig koncentracije na 2 M je zvišal obnovitev adsorpcijske sposobnosti s 30 na 50%. Regeneracija bentonita tako ni bila uspešna.
Ključne besede
bentonit;težkohlapne lipofilne snovi;adsorpcija;regeneracija;odpadne vode;diplomske naloge;
Podatki
Jezik: |
Slovenski jezik |
Leto izida: |
2021 |
Tipologija: |
2.11 - Diplomsko delo |
Organizacija: |
UM FKKT - Fakulteta za kemijo in kemijsko tehnologijo |
Založnik: |
[D. Homšak] |
UDK: |
628.316.12:552.523(043.2) |
COBISS: |
80440835
|
Št. ogledov: |
467 |
Št. prenosov: |
32 |
Ocena: |
0 (0 glasov) |
Metapodatki: |
|
Ostali podatki
Sekundarni jezik: |
Angleški jezik |
Sekundarni naslov: |
Study of adsorption of lipophilic compounds onto bentonite |
Sekundarni povzetek: |
The purpose of this thesis is to study bentonite for the removal of lipophilic compounds from aqueous solutions via an adsorption mechanism.
The sample of bentonite was characterized; microscopy analysis was performed for elemental composition' determination, zeta potential, and particle size distribution were determined. Zeta potential value was 0,229 mV, average particle size was 1833 nm and PDI was 0,52.
Adsorption efficiency was determined by gravimetrical analysis. We used hexane as our extraction media. Adding 1 g of bentonite to our model solution with the initial concentration of 6,92 g/L and agitating for 18 h, we removed 98,5 % of lipophilic content. Experimental data fit both Freundlich and Langmuir isotherm, with the former being a better fit in this case. It is presumed that the adsorption was multi-layer. The adsorption capacity was determined to be 2322 mg/g.
Bentonite was later tested on real wastewater samples from the cosmetic industry. We added 1 g of bentonite and agitated for 18 h. Adsorption efficiency was lowering with the increase of lipophilic concentration in the sample. We removed 93,0 % of lipophilic content from our sample with an initial concentration of 446 mg/L. In addition, we measured the pH of our sample solutions. Results came back at ~7.1 and rose slightly with increasing concentration.
We tried to regenerate the exhausted bentonite with 0,1 M NaOH solution. The time of regeneration agitation was 4 h. The procedure was repeated 4 times altogether. The adsorption efficiency lowered greatly after the first regeneration cycle and didn't lower further after the following repetitions. Increasing the time of regeneration agitation on 18 h did not have an effect. Increasing the concentration to 2 M NaOH increased the regeneration efficiency from 30 to 50 %. In conclusion, the regeneration of bentonite was not successful. |
Sekundarne ključne besede: |
bentonite;low-volatile lipophilic compounds;adsorption;regeneration;wastewater; |
Vrsta dela (COBISS): |
Diplomsko delo/naloga |
Komentar na gradivo: |
Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo |
Strani: |
IX, 34 str. |
ID: |
13305827 |