A series of aminopropyl-functionalized silica nanoparticles were prepared through a basic two step sol-gel process in water. Prior to being aminopropyl-functionalized, silica particles with an average diameter of 549 nm were prepared from tetraethyl orthosilicate (TEOS), using a Stöber method. In a second step, aminopropyl-silica particles were prepared by silanization with 3-aminopropyltriethoxysilane (APTES), added drop by drop to the sol-gel mixture. The synthesized amino-functionalized silica particles are intended to be used as supports for immobilization of humic acids (HA), through electrostatic bonds. Furthermore, by inserting beside APTES, unhydrolysable mono-, di- or trifunctional alkylsilanes (methyltriethoxy silane (MeTES), trimethylethoxysilane (Me3ES), diethoxydimethylsilane (Me2DES) and 1,2-bis(triethoxysilyl)ethane (BETES)) onto silica particles surface, the spacing of the free amino groups was intended in order to facilitate their interaction with HA large molecules. Two sorts of HA were used for evaluating the immobilization capacity of the novel aminosilane supports. The results proved the efficient functionalization of silica nanoparticles with amino groups and showed that the immobilization of the two tested types of humic acid substances was well achieved for all the TEOS/APTES = 20/1 (molar ratio) silica hybrids having or not having the amino functions spaced by alkyl groups. It was shown that the density of aminopropyl functions is low enough at this low APTES fraction and do not require a further spacing by alkyl groups. Moreover, all the hybrids having negative zeta potential values exhibited low interaction with HA molecules.

The application of selenium (Se) to tomatoes enhances accumulation of bioactive compounds. The physiological window of Se is very narrow, and Se overdose reduces the yield. Glycine betaine was shown to reduce Se’s negative effects on plants and to potentiate its beneficial effects. In this study, baker’s yeast vinasse (BYV), as an affordable source of glycine betaine, was tested for its interaction with Se in an optimized foliar fertilizer. The application dose was selected after a laboratory experiment, wherein assays on plant height, leaves surfaces, stomatal conductance, and chlorophyll fluorescence were done. The Se and BYV supplemented foliar fertilizers were tested for their effects on accumulation of bioactives in drip-irrigated tomatoes cultivated in a greenhouse. Under laboratory conditions, assays demonstrated Se and BYV induced effects on tomatoes plants. Both the stomatal conductance and photosynthesis efficiency increased compared to a water treated control. The greenhouse experiment demonstrated that BYV and Se addition increases the number of tomato fruits in the “extra” marketable class and enhances the accumulation of ascorbic acid, carotenes, polyphenols, and flavonoids. The effects depend on the composition of the foliar fertilizer, the most significant effects being recorded for the foliar applied product with the highest BYV and nitrogen content.

In this study, non-irradiated and weathered multiwalled carbon nanotubes (MWCNTs) obtained through irradiation, were studied as adsorbents for BPA, both nanomaterials being characterized before and after the adsorption process. The objectives of our investigation were to compare the characteristics of non-irradiated and irradiated MWCNTs, to evaluate the adsorption capacity of BPA by pristine and irradiated MWCNTs and to determine the variation of the kinetic, sorption and thermodynamic parameters during sorption process using both sorbents.

The paper presents new results on the application of collagen hydrolysates characterised in terms of molecular weight, polydispersity (GPC/ SEC), chemical composition and free amino acid composition (GC-MS) for the treatment of cereal seeds. Surface tension and contact angle determinations (VGA Optima XE) have highlighted an improvement in the hydrophilicity of collagen hydrolysates in pesticide mixtures as premises for the adherence of wheat seeds onto the surface. The identification of a 39% higher gibberellic acid concentration (RP-HPLC) in germinated seeds in the collagen hydrolysate, and the presence of free amino acids and low molecular weight fractions were correlated with the biofertilizing and biostimulating effects registered in field experiments on wheat crops.