| Summary: | Biofouling is a common and pervasive problem which reduces the efficiency of man-made marine structures. Silver-zeolite (AgZ) nanocomposite material is proposed as a promising anti-microfouling agent. Metallic silver nanoparticles were immobilized on silver ion doped ZSM-5 zeolites using a green reducing agent, trisodium citrate. The stable and porous inner structure of ZSM-5 zeolites performs a dual role as a stable size-control template and a reservoir of antimicrobial nanosilver. SEM revealed the globular and cluster-like morphology of the AgZ composites, with a homogenous distribution of silver particles on the surface of the AgZ clusters, while TEM analysis indicated Ag nanoparticles could be detected both on the surface and within the zeolite. UV-visible analysis on AgZ displayed the characteristic surface plasmon resonance absorption maximum for Ag nanoparticles ranging from 408 to 500 nm. Indeed, BET analysis also showed a reduction in surface area of up to 44% with the incorporation of Ag nanoparticles into the zeolite, indicating the formation and growth of Ag within ZSM-5 zeolite. XRD analysis indicated the presence of metallic Ag while the ZSM-5 crystalline framework remained largely intact after the Ag crystal growth process. The AgZ nanocomposites were evaluated for their biofilm inhibition activity against Halomonas pacifica, a common marine bacterium implicated in the early stages of biofouling. AgZ loaded with up to 10 wt% Ag reduced biofilm attachment by 81%, and inhibited the growth of marine microalgae Dunaliella tertiolecta and Isochrysis sp. Overall, results demonstrated the effective anti-microfouling property of AgZ nanocomposites.
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