Ημερολόγιο Εκδηλώσεων

Περιγραφή:
ΠΟΛΥΤΕΧΝΕΙΟ ΚΡΗΤΗΣ Σχολή Μηχανικών Ορυκτών Πόρων - Διεθνές ΠΜΣ IMACS Θέμα Μεταπτυχιακής Εργασίας: «Characterization and antibacterial properties of modified bentonites in animal litter applications» Τριμελής Εξεταστική Επιτροπή: Καθ. Χρηστίδης Γεώργιος (επιβλέπων) Επ. Καθ. Βενιέρη Δανάη Assoc. Prof. Patricia Patrier (University of Poitiers, France) Περίληψη Two Bentonites from Milos Island, Greece, were characterised and modified in order to develop antibacterial animal litter. Rema Bentonite is a poor quality bentonite containing 29% montmorillonite of low layer charge. Its clay fraction is composed of montmorillonite, muscovite and clay size clinoptilolite, which confers great CEC (56.3 meq/100g) compared to the smectite content. FTIR and XRF analysis confirm the presence of montmorillonite with Mg and Fe substitutions, with K-rich interlayer, in accordance with its volcanic ash weathering origin. S2 bentonite is a good quality bentonite consisting of 70% low layer charge beidellite. FTIR and XRF confirm Mg and Fe substitutions in the lattice and Na-rich interlayers that is in accordance with its natural tendency to form stable suspension when added in water. Its measured CEC is 60.9 meq/100g. Both Rema and S2 bentonites were modified with known antibacterial agents. Cu-modified bentonites and Ag-modified bentonites were prepared through cation exchange with a solution concentration of 1% of respective CEC. The presence of these cations in interlayer is verified with XRD bulk sample analysis. Al-modified and B-modified bentonites does not contain these cations in interlayer. They are in porous water after overnight contact time. The antibacterial properties of natural and modified bentonites were assessed through MIC and MBC experiments on S. aureus (gram +), P. aeruginosa (gram -), E. coli (gram -) and K. pneumoniae (gram -). Natural Rema bentonite does not have strong antibacterial properties but modified Rema bentonites have strong. The best “dopant” is silver but because of its toxicity and light reduction in Ag(s) nanoparticles, it is not advised to use it as animal litter. Copper, Aluminium and Boron have great bacteriostatic and bactericidal effect that are dose and gram-type dependent. Natural S2 bentonite has strong bacteriostatic and bactericidal effect because of an unknown antibacterial component. Modification did not enhanced significantly its antibacterial action. Toxicity assessment on natural interlayer antibacterial compound is needed, but the results show that the material might be an animal litter great antibacterial properties. The development of animal litter based on this two bentonites is possible and modification depends on company wishes. In addition, it is probably possible to develop an antibacterial clumping litter based on the S2 bentonite and an antibacterial litter without clumping behaviour based on Rema bentonite.