Widespread application of synthetic nematicide on the crops aimed to fight nematode parasite could be a threat to human health and overall environmental quality. Most of synthetic nematicides have been withdrawn from the market, due to their toxicity. This had led to looking for a non-chemical alternative which must be equally effective and eco-friendly, derived from natural materials, aiming to reduce synthetic pesticide input. Recently, it has been proved that an aldehyde, namely furfural, is effective against Meloidogyne sp. (a dangerous specie of nematode) . This latter biomolecule can be easily extracted from Melia azedarach fruits, a tree growing in tropical and subtropical areas. This work is part of a wider multidisciplinary project, which aims to develop an innovative, easy to produce, and eco-sustainable nematicidal formulate by combining a botanical extract of known nematicidal activity with environmentally friendly porous materials. Specifically, an aldehyde - namely, furfural and salicylaldehyde, which is known for its occurrence in Melia azedarach (MA) tree and mainly responsible for the plant defense ability against nematodes - wase encapsulated into microporous alumina-silicate matrices (zeolites) to obtain a nematicidal formulate with a controlled release of the bioactive aldehyde. From a structural point of view, the project is focused on the study of interactions that take place between the guest nematicidal molecule and the host zeolite carrier in order to elucidate, at an atomistic level, the mechanisms that control the adsorption (encapsulation) and desorption (controlled release) properties. The first part of the project was addressed to define the zeolite with the highest encapsulation capacity and that was capable to prolong the bioactivity of the embedded products (encapsulated aldehyde). With this purpose, several zeolites (zeolite Y, mordenite, ferrierite, beta and ZSM-5) with different silica/alumina ratio (from 10 up to 500), pore architecture and type/position of adsorbing sites were tested. In this study the furfural encapsulation into microporous alumina-silicate ZSM-5 (SiO2/Al2O3 = 500) zeolite will be discussed. Furfural was encapsulated into zeolite via adsorption from water and adsorption equilibrium was monitored by adsorption kinetics. Adsorption isotherms were determined in order to define the affinity and maximal adsorption capacity and selectivity of tested zeolite for the selected nematicide. The monitoring was done by liquid chromatographic analysis (HPLC) of equilibrium solutions performed via Jasco 880-PU Intelligent and thermogravimetric analysis (25°-900°C, heating rate 10°C/min) of loaded zeolite samples. Electronic nose data were collected on AIRSENSE PEN3. After adsorption, the zeolite samples were structurally characterized with X-ray diffraction (XRD) technique (Bruker D8 Advance diffractometer equipped with SOL-X detector) - coupled with Rietveld refinements of the diffraction patterns. Structural analysis was used to prove the embedding of the aldehydes inside the zeolite pores and to define the interaction distance between the porous framework and each molecule. This combined diffractometric, chromatographic and thermogravimetric study allowed us to: 1) evaluate the maximum adsorption capacity of hydrophobic zeolite against furfural molecules ; 2) localise the biomolecules in the zeolite channel system; 3) probe the interaction between the adsorbate and the zeolite framework; 4) evaluate the release kinetics of the encapsulated molecules in gas phase. Our results highlighted that ZSM-5 can be useful tool for nematode pest management, and may help improving environmental protection while minimizing risk to overall health.  Ntalli, N. G., Cottiglia, F, Bueno, C. A., Alché, L. E., Leonti, M, Vargiu, S., Bifulco, E., Menkissoglu-Spiroudi, U., Caboni, P. (2010): Cytotoxic tirucullane triterpenoids from Melia azedarach fruits. Molecules, Ann. Appl. Biol. 15, 5866-5877.
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|Titolo:||Zeolites for sustainable agricolture: furfural encapsulation and controlled release in ZSM-5|
|Data di pubblicazione:||2016|
|Appare nelle tipologie:||04.2 Contributi in atti di convegno (in Volume)|