Synthesized layered inorganic-organic magnesium organosilicate containing a disulfide moiety as a promising sorbent for cations removal

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)A new-layered inorganic-organic magnesium organosilicate was synthesized through a single step template sol-gel route under mild conditions, using a new alkoxysilane, containing a 2-aminophenyldisulfide molecule. Elemental analysis data based on the nitrogen atom showed an incorporation of 1.97 mmol of organic pendant groups for each gram of the hybrid formed. The X-ray diffraction patterns demonstrated that this nanocompound exhibited lamellar structure, in agreement with that found for natural inorganic silicates. Infrared spectroscopy and nuclear magnetic resonance for the (29)Si nucleus in the solid state are in agreement with the success of the proposed synthetic method. The presence of nitrogen and sulfur basic centers attached to the pendant groups inside the lamellar structure is used as basic centers to coordinate cations from aqueous solution at the solid/liquid interface. The isotherms were fitted to Langmuir and Freundlich models. The maxima adsorption capacities for copper, lead and cadmium, calculated from Langmuir model, were 3.28, 1.42 and 0.35 mmol g(-1), respectively. These values are comparable to other adsorbing nanomaterials. This behavior suggested that this new inorganic-organic hybrid could be employed as a promising adsorbent for cation removal from polluted systems. (c) 2008 Elsevier B.V. All rights reserved.16016369Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Organofunctionalized magnesium phyllosilicates as mono- or bifunctitonal entities for industrial dyes removal

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Magnesium phyllosilicates with organic groups anchored onto the inorganic polymeric backbones as mono-or bifunctional entities were investigated for dye removal from aqueous solution. The synthetic methodology consisted in obtaining organofunctionalized nanostructured materials from silylating agents of general formula R-1-Si(OCH3)(3), in which R-1-trimethoxysilane includes chains containing the functional groups: 3-aminopropyl, octadecyldimethyl(silylpropyl)ammonium, 3-mercaptopropyl, 3-ethylenediamine and 3-diethylenetriamine. The sol-gel process leads to lamellar structures similar to those of natural silicate with basal distances, in good agreement with the R-1 contained in the precursor agent. The pendant electrophile attached on the new phyllosilicates interacts with the negative charge of dyes used in the textile industry, such as Reactive Yellow GR, Reactive Red RB and Reactive Blue RN. The sorption studies showed that the phyllosilicate containing octadecyldimethyl(3-trimethoxysilylpropyl)ammonium chloride agent, P-OCT, presented the highest sorption capacities of 1343, 1286 and 344 mg g(-1) for the dyes Yellow GR, Blue RN and Red RB, respectively, which are better than for other sorbing materials. Real samples from textile effluents assayed demonstrated that the sorption did not need to adjust the initial pH, with surface saturation after 3 h and the minimum mass necessary was 2.5 g dm(-3) of P-OCT for the best efficiency. This is thus a very promising material for textile effluent treatment, with good structural disposition of the pendant groups.2835023511Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq