Arbuscular mycorrhizal fungi (AMF) increase the uptake of soluble phosphates, while phosphorus solubilizing fungi (S) promote the solubilization of insoluble phosphate complexes, together benefiting plant nutrition. The use of these organisms in combination with minerals or rocks that provide nutrients is another alternative to maintain crop productivity. The objective of this work was to combine AMF and S with pyroclastic materials (ashes and pumicites) from the Puyehue volcano and phosphoric rocks (PR) from the Río Chico Group (Chubut) and to evaluate the performance of these mixtures as substrates for potted production of Lactuca sativa. To formulate the substrates, a mixture of Ter-rafertil® with ashes was used as a base. Penicillium thomii was the S and spores of the fungus Rhizophagus intraradices (AEGIS® Irriga) served as the source of AMF. Various combinations of microorganisms and the addition or not of RP were evaluated. The treatments were: (1) substrate; (2) substrate + AMF; (3) substrate + S; (4) substrate + AMF + S; (5) substrate: PR; (6) substrate: PR + AMF; (7) substrate: PR + S, and (8) substrate: PR + AMF + S. There were 3 replicates per treatment. The parameters evaluated were total and assimilable P content in the substrate, P in plant tissue and dry biomass. All of them were significantly higher in the plants grown in the substrate added with PR and inoculated with S and AMF. This work confirms that the S/AMF combination with volcanic ashes from Puyehue and PR from Grupo Río Chico formulated with a commercial substrate promote the growth of L. sativa. Thus, it is possible to increase the added value of geomaterials of national origin.

We studied Zeta potentials of nanoparticles titanium dioxides （nTiO₂） in different concentration of NaNO₃ and phosphate (P) solutions. In addition, the effect of flow rate on the transport of nTiO₂ in P was investigated at pH＝6.5. Experimental results show that the Zeta potential of nTiO₂ is compressed with the increasing ion concentration (IC) of NaNO₃ at pH＝6.5. The negative charge increases with the augment of P. Therefore, the high P and low NaNO3 induce the stabilization of nTiO₂ aggregates. The transport experiments suggest that the rapid flow rate is favorable for the transportability of nTiO₂ and soluble phosphate. The breakthrough transport curves (BTCs) of nTiO₂ in sand columns can be fitted well with two-site kinetic attachment model. The modeling results suggest that the values of first-order attachment rate coefficients (k₂) and detachment rate coefficients (k_2d) on site 2 and first-order attachment rate coefficients (k₁) on site 1 are responsible to the attaching efficiency of nTiO₂ on sands and their transportability.

Magnesium hydroxide/melamine phosphate borate (nano MH/MPB), a novel nano-composition intumescent flame retardant, was synthesized with the in-situ reaction method from MgCl₂·6H₂O sodium hydroxide (NaOH) and melamine phosphate borate (MPB) in the absence of H₂O. The structure of the product was confirmed by EDAX IR and XRD. The effects of reaction temperature and time on the dimension of magnesium hydroxide were observed. The effects of mass ratio of magnesium hydroxide to MPB on the flame retardancy of nano-MH/MPB/EP were examined with the limiting oxygen test. The results show that the optimal condition of synthesis of MH/MPB is m_MH/m_MPB = 0.25, reacting under 75 ℃ for 30 minutes. Finally, the mechanism for flame retardancy of nano-MH/MPB/EP was pilot studied by means of IR of char layer and TG of MH/MPB.