Συντάχθηκε 10-03-2026 09:17
Τόπος:
Σύνδεσμος τηλεδιάσκεψης
Έναρξη: 13/03/2026 15:00
Λήξη: 13/03/2026 16:00
First Name/Surname: Eleftheria Sperelaki
Student Identification Number: 2023057613
Date: 13/3/2026
Time: 15:00
Room / Zoom Link: Join Zoom Meeting
https://tuc-gr.zoom.us/j/93590048736?pwd=AvC0HpuazzzJSWKwNdxuCPaaEbnWe8.1
Meeting ID: 935 9004 8736
Password: 995614
Title: “Synthesis of Chitosan-ZnO Nanoparticles: Behavior in Porus Media in the Presence of Deltamethrin and Effectiveness Against Pathogens ”
Supervisor: Constantinos Chrysikopoulos
Three-member committee:
1. Constantinos Chrysikopoulos
2. Petros Gkikas
3. Anastasios Malandrakis
Abstract: Persistent organic pollutants, such as pesticides, medicines, and other emerging contaminants, continue to pollute aquatic habitats, posing a significant global issue because current treatment technologies often fail to remove these chemicals effectively. The development of multifunctional, environmentally friendly nanomaterials is a promising solution for water purification and sustainable agriculture management. Chitosan, a biodegradable, non-toxic biopolymer with high adsorptive capacity, is gaining popularity, especially when combined with metal oxides such as ZnO to form nanocomposites with improved physicochemical and antibacterial properties. Deltamethrin, a popular pyrethroid insecticide, is highly hydrophobic and readily persists in the environment, posing risks to soil, water, and non-target organisms. Understanding its adsorption, transport, and interactions with natural and manufactured materials is critical for evaluating environmental fate and devising efficient remediation solutions.
In this study, the adsorption capacity of chitosan-zinc oxide (CS-ZnO) nanoparticles for deltamethrin was investigated under a range of environmentally relevant physicochemical conditions, including changes in initial pesticide concentration, pH, and ionic strength. Complementary column experiments were used to evaluate the mobility and retention of deltamethrin and CS-ZnO nanoparticles in quartz-sand porous media under flow conditions. Furthermore, the antifungal activity of CS-ZnO NPs was evaluated against important phytopathogenic fungi to assess their potential as sustainable pesticide alternatives.
The results demonstrated that deltamethrin adsorption kinetics follow a pseudo-second-order model under all conditions, suggesting that chemisorption is the primary adsorption process. pH and ionic strength had a considerable influence on adsorption efficacy. The most favourable adsorption occurred at neutral to mildly alkaline pH and moderate ionic strength. In contrast, acidic pH and excessive salinity significantly reduced adsorption capacity due to protonation of functional groups, electrostatic screening, and nanoparticle aggregation. The addition of quartz sand affected both the extent and kinetics of adsorption, shifting the optimum removal in lower deltamethrin concentrations and altering ionic-strength interactions.
Deltamethrin exhibited strong retention in the porous media (77-80%), whereas CS-ZnO nanoparticles showed high mobility and low retention due to their greater colloidal stability. Co-transport experiments revealed that nanoparticles increased deltamethrin mobility in acidic conditions but promoted substantial retention at neutral and alkaline pH due to pesticide-nanoparticle agglomeration and straining.
Fungitoxicity studies revealed that CS-ZnO nanoparticles exhibit high, dose-dependent antifungal activity, resulting in significant growth inhibition across a range of phytopathogenic fungal species including C. gloeosporioides, M. fructicola, Penicillium spp., B. cinerea, and A. alternata. The chitosan-derived biocompatibility and fungitoxic action based on ZnO-mediated oxidative stress, suggest that CS-ZnO nanoparticles a potent, ecologically acceptable alternative to conventional fungicides. Overall, the synthesized CS-ZnO nanoparticles represent a novel and promising solution for reducing the environmental footprint of pesticides both for use as filter material against xenobiotics and as an environmentally compatible plant protection agent.
