Synthesis and characterization of materials obtained by modification of natural zeolite (clinoptilolite) and phosphate based microporous materials with zeolitic structure

Abstract

In the first part of the dissertation, the possibility of modifying the zeolitic tuff from the mine Zlatokop (near Vranjska Banja) was investigated in order to obtain new adsorbents. The second part presents the possibility of synthesize of new phosphate‐based microporous materials with structural properties of zeolites. The zeolitic tuff modified with benzalkonium chloride (BC) was tested as an adsorbent for the salicylate‐anions (SA). SA‐enriched zeolite was further studied as a model system for the controlled release of the pharmacologically active substance as well as a disinfectant toward the pathogenic bacteria: Gram‐negative Escherichia coli and Gram‐positive Staphylococcus aureus. It was found that about 80% of the adsorbed salicylate is delivered into solution during 5 hours. The release profile of SA from BC‐modified zeolite into solution is in a good agreement with the Korsmeyer‐Peppas kinetic model, which is usually used for description of the release kinetics of the pharmacologically active substances from different substrates. The zeolitic tuff modified with hydrated iron(III) oxide was investigated as an adsorbent for selenite and selenate ions. The adsorbent binds the anions through formation of Se‐O‐Fe and Se‐O‐Si bonds and oxo‐complexes. The spent adsorbent was tested as a supplement for the cultivation of mushroom Pleurotus ostreatus. The mushrooms grown on the substrate show possibility to adopt selenium from the surface and transfer it into selenoproteins. Structural role of 3‐methylaminopropylamine (MPA) in the synthesis of the porous inorganic phosphate‐based polymers was tested in the second part of thesis. The influence of temperature and time, the mole ratio of reactants and the presence of fluoride ions on the crystallization of aluminophosphates, metalsubstituted aluminophosphates and zincophosphates was investigated. Some of the obtained crystalline products are isostructural with the known alumo‐ and galophosphates, while others are new crystalline products.

U prvom delu disertacije ispitana je mogućnost modifikacije zeolitskog tufa iz rudnika Zlatokop (okolina Vranjske Banje) u cilju dobijanja novih adsorbenata, dok je u drugom delu opisana mogućnost sintetisanja novih mikroporoznih jedinjenja sa strukturnim svojstvima zeolita, na bazi fosfata. Zeolitski tuf modifikovan benzalkonijum‐hloridom (BC) ispitan je kao adsorbent salicilata (SA). SA‐obogaćeni zeolit je dalje ispitan kao model sistem za kontrolisano otpuštanje farmakološki aktivne supstance i kao dezinficijens u odnosu na bakterije: Gram‐negativnu Escherichia coli i Gram‐pozitivnu Staphylococcus aureus. Utvrđeno je da oko 80% salicilata pređe u rastvor sa adsorbenta tokom 5 sati. Kinetika desorpcije prati Korsmajer‐Pepasov kinetički model koji najčešće opisuje kinetiku otpuštanja farmakološki aktivnih supstanci sa različitih podloga. Zeolitski tuf modifikovan hidratisanim gvožđe(III)‐oksidom ispitan je kao adsorbent selenit‐ i selenat‐jona. Ovaj adsorbent vezuje ispitivane anjone tako što na površini adsorbenta dolazi do obrazovanja oksokompleksa i Se‐O‐Fe i Se‐O‐Si veza. Ovaj adsorbent ispitan je i kao supstrat u uzgoju medicinski značajne gljive Pleurotus ostreatus (bukovače). Gljive uzgajane na ovom supstratu usvajaju selen sa površine adsorbenta i prevode ga u selenoproteine. U drugom delu teze ispitana je strukturna uloga 3‐metilaminopropilamina (MPA) u sintezi poroznih neorganskih polimera na bazi fosfata. Praćen je uticaj temperature i vremena, molskog odnosa reaktanata i prisustva fluorid‐jona na kristalizaciju alumofosfata, metal‐supstituisanih alumofosfata i cinkfosfata. Dobijeni su različiti kristalni proizvodi od kojih su neki izostrukturni sa već poznatim alumo‐ i galofosfatima, a neki su novi kristalni proizvodi.