<p>Uklanjanje amonijaka iz podzemnih voda u cilju dobijanja<br />pijaće vode predstavlja značajan problem, koji se do sada<br />rešavao primenom različitih postupaka. Poznato je da zeoliti<br />kao prirodni jonoizmenjivači i adsorbenti kvalitetno vezuju<br />amonijum jone u svoju alumosilikatnu matricu. Njihova<br />efektivnost, u različitim tehnološkim procesima, zavisi od<br />fizičko-hemijskih osobina, koje su usko povezane sa njihovim<br />geološkim nalazištima, kada se govori o prirodnim zeolitima.<br />Pored prirodnih zeolita u praksi se koriste i sintetički zeoliti<br />dobijeni raznim postupcima. Danas, je komercijalna primena<br />sintetičkih zeolita rasprostranjenija u odnosu na primenu<br />prirodnih, zbog čistoće kristalnih proizvoda i uniformne<br />veličina čestica. Crystal-Right™ (CR-100) je zeolit koji spada u<br />grupu najizdržljivijih proizvedenih minerala. Ovaj zeolit<br />podiže pH vrednost tretiranih voda, dok istvremeno smanjuje<br />tvrdoću i uklanjanja gvožđe i mangan. Ovo podešavanje pH i<br />uklanjanje nepoželjnih mineralnih materija postiže se izvrsnim<br />osobinama ovog zeolita u pogledu filtriranja, ali i ispiranja<br />nakon primene.<br />Maksimalna količina adsorbovanog amonijaka iznosi 2,31 mg<br />(98%) i 2 mg (87%), iz model rastvora i uzorka podzemne,<br />bunarske vode, redno. Prisustvo drugih komponenti u<br />bunarskoj vodi uzrokuje promene u količini adsorbovanog<br />amonijaka na zeolitu. Najbolje uklanjanje postignuto je za<br />jone kalijuma već sa najmanjim masama upotrebljenog<br />zeolita. Nasuprot tome, joni kalcijuma i magnezijuma se pri<br />nižim vrednostima doziranja zeolita slabije uklanjaju iz<br />bunarske vode, dok sa porastom doziranja raste i efikasnost<br />uklanjanja na svim posmatranim temperaturama.<br />Izbor adsorpcione izoterme je pokazao da najbolje rezultate<br />daje Freundlich-ova adsorpcione izoterme, a rezultati<br />aproksimacije ukazuju na fizičku adsorpciju na heterogenoj<br />površini. Negativne vrednosti entropije aktivacije upućuju na<br />zaključak da se radi o asocijativnoj adsorpciji amonijaka na<br />površinu zeolita, odnosno da postoji interakcija između<br />adsorbovanih molekula. Vrednosti entalpije aktivacije od<br />15,096 kJ/mol i 28,978 kJ/mol, za model rastvor i realan<br />sistem, redno, upućuju da se radi o endotermnom procesu,<br />što i potvrđuju podaci o ravnotežnim koncentracijama na<br />različitim temperaturama.<br />Tokom eksperimenata izvedenih sa poluindustrijskom<br />kolonom ispunjenom zeolitom Crystal Right™ (tip CR-100)<br />potvrđena je efikasnost u uklanjanju zeolita iz bunarske vode.<br />Između ispitanih modela za određivanje kinetike u kolonskom uređaju najboljim se pokazao model Yoon-Nelson-a.<br />Koeficijent linearne korelacije za model Yoon-Nelson-a iznosi -<br />0,975, dok je koeficijent determinacije imao vrednosti 0,950.<br />Iako je model razvijen jednokomponentne sisteme pokazao<br />se kao zadovoljovajući iako se radi o realnom sistemu<br />podzemne bunarske vode koja sadrži brojne rastvorene<br />supstance, katjone zemnoalkalnih i alkalnih metala, huminske<br />kiseline, anjone itd. Može se primetiti da je postignuto<br />zadovoljavaće slaganje eksperimentalnih podataka o<br />vremenu probaja sloja (50%) sa Yoon-Nelson-ovim modelom,<br />eksperimentalno određeno vreme proboja sloja iznosi oko 59<br />časova, dok je modelom dobijeno vreme 62 časa. Konstanta<br />brzine Yoon-Nelson-ovog modela iznosi 0,051 1/h.</p> / <p>Removing ammonia from groundwater to obtain drinking<br />water is an important issue, which is so far solved using<br />different methods. It is known that zeolites as natural ion<br />exchangers and adsorbents that bind ammonium ions in its<br />aluminosilicate matrix. Their effectiveness in various<br />technological processes depends on the physical and<br />chemical properties, which are closely related to their<br />geological sites, when it comes to natural zeolites. In addition<br />to the natural zeolites in practice synthetic zeolites are used.<br />Today, the commercial application of synthetic zeolites is<br />widespread in relation to the use of natural, due to the purity<br />of crystal products and uniform particle size. Crystal-Right ™<br />(CR-100) is a zeolite among the most durable minerals<br />produced. This zeolite raises the pH of the treated water, while<br />the same time it reduces the hardness and remove iron and<br />manganese. This pH adjustment and removal of undesirable<br />mineral substances is achieved by the excellent characteristics<br />of the zeolite in terms of filtering, and rinsing after application.<br />The maximum amount of adsorbed ammonia at 2.31 mg<br />(98%) and 2 mg (87%), from the model solution and the<br />sample of groundwater, well water, respectively. The presence<br />of other components in the well water causes changes in the<br />amount of ammonia adsorbed on zeolite. Selection of<br />adsorption isotherms showed that the best results are<br />achieved by Freundlich's adsorption isotherm, and the results<br />indicate physical adsorption on heterogeneous surfaces.<br />Negative values of entropy of activation lead to the<br />conclusion that it is associative adsorption of ammonia on the<br />surface of the zeolite, or that there is an interaction between<br />the adsorbed molecules. The values of enthalpy of activation<br />of 15,096 kJ / mol and 28,978 kJ / mol, for the model solution<br />and real system, respectively, indicating that it is an<br />endothermic process, which is confirmed by data on the<br />equilibrium concentrations at different temperatures.<br />Experiments conducted with the pilot plant column filled with<br />zeolite Crystal Right ™ (type CR-100) confirmed the<br />effectiveness in removing zeolite from well water. Among the<br />surveyed models to determine the kinetics of the column<br />device Yoon-Nelson's model has proven to be the best. The<br />linear correlation coefficient for the model Yoon-Nelson's is -<br />0.975, and the value of the coefficient of determination was 0.950. Although the model developed for one-component<br />systems it is proved to be satisfactory for ground water<br />ammonia adsorption. The agreement between experimental<br />data on the breakthrough point at 50% concentration (59<br />hours) with Yoon-Nelson's model, is good (62 hours). Constant<br />of Yoon-Nelson's model is 0.051 1 / h.</p>
| Identifer | oai:union.ndltd.org:uns.ac.rs/oai:CRISUNS:(BISIS)102328 |
| Date | 29 December 2016 |
| Creators | Tomić Željko |
| Contributors | Jokić Aleksandar, Zavargo Zoltan, Vulić Tatjana, Sokolović Dunja |
| Publisher | Univerzitet u Novom Sadu, Tehnološki fakultet Novi Sad, University of Novi Sad, Faculty of Technology at Novi Sad |
| Source Sets | University of Novi Sad |
| Language | Serbian |
| Detected Language | Unknown |
| Type | PhD thesis |
Page generated in 0.0029 seconds