Abstract
In this paper, the results of adsorption of uranyl ion on acid-modified zeolitic mineral clinoptilolite are presented. Adsorption was investigated at different amounts of solid phase in suspension, as well as at different pH values. The modified clinoptilolite samples were obtained by treatment of clinoptilolite with acids: hydrochloric, oxalyc and citric. Starting and modified clinoptilolites were characterized by chemical analysis, thermal (DT/TG) analysis and by determination of cation exchange capacity, while starting and nonadsorbed amounts of uranyl ion were determined by fluorometric method. Uranyl ion adsorption experiments on natural unmodified zeolitic mineral showed that uranyl ion adsorption was low (29.2%) and that treatment of clinoptilolite with acids significantly increases the adsorption of uranyl ion (>90%). In the case of acid treated clinoptilolites, the highest adsorption of uranyl ion was achieved on clinoptilolite modified with hydrochloric acid. Kinetics of adsorption showed that adsorption of uranyl ion begins very fast and that the most of uranyl ion was adsorbed in first 30 min. Practically, there were no changes in uranyl ion adsorption within next 72 h.
Highlights
Suspenzija (5%) mešana je 1 h na 60 °C, posle čega je kontakt sa kiselinom prekidan, uzorak ispiran destilovanom vodom do negativne reakcije na hloride, oksalate ili citrate u filtratu i sušen na 105 °C do konstantne mase
Endotermni efekat na ~700 °C, koji je kod polaznog uzorka Ca-klino posledica prisustva karbonata u uzorku, nestaje kiselinskim tretmanom sa HCl (H-klino), i posledica je rastvaranja karbonata u mineralnim kiselinama
Na pH 6, pri višim masenim odnosima adsorbent:uranil-jon (400:1, 200:1 i 100:1), adsorpcija uranil-jona na ispitivanim adsorbentima opada u sledećem nizu: H-klino > LH-klino > OH-klino i izbor kiseline značajnije utiče na indeks adsorpcije
Summary
U ovom radu prikazani su rezultati ispitivanja adsorpcije uranil-jona na zeolitskom mineralu klinoptilolitu modifikovanom tretmanom kiselinama. Drugi faktor koji pospešuje adsorpciju na H-klinoptilolitu jeste veličina hidronijum jona. Da bi videli kako tip kiseline utiče na stabilnost strukture minerala klinoptilolita i adsorpciju uranil-jona napravljeni su H-oblici zeolita tretiranjem sa monobaznom hlorovodoničnom kiselinom, dvobaznom oksalnom i trobaznom limunskom kiselinom. Cilj ovih eksperimenata je da se vidi da li jačina kiselih centara utiče na adsorpciju uranil-jona ili je eventualna promena adsorpcije izazvana delimičnom promenom kristalne strukture zeolita. Budući da je ovakav sistem složen jer se na površinu klinoptilolita koja ima izmenljive katjone vezuje hidronijum jon, a zatim uranil-jon, bilo je važno ispitati kako modifikacija površine utiče na adsorpciju uranil-jona. Zbog toga je ispitivanje adsorpcije uranil-jona (kao zagađivača životne sredine sa hemijskim i radiološkim rizikom) pri različitim masenim odnosima adsorbenata i na različitim pH izabrano za temu ovog rada
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
