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Cellulose (Cel) was first chemically modified with thionyl chloride to increase its reactivity. In the next step CelCl was reacted with ethylenediamine (CelEn) and subsequently reacted with ethylene sulfide to obtain a solid substance, CelEnEs. The modification reactions were confirmed by elemental analysis, TG, XRD, (13)C NMR and FTIR. The chemically modified biopolymer CelEnEs had an order of divalent metal sorption of Pb(2+)>Cd(2+)>Ni(2+)>Co(2+)>Cu(2+)>Zn(2+), and the maximum adsorption capacities were found to be 6.282±0.023, 5.783±0.015, 5.561±0.017, 4.694±0.013, 1.944±0.062 and 1.733±0.020 mmol g(-1), respectively. The equilibrium data were fitted to Langmuir, Freundlich and Temkin models, and in general, the experimental data best fit the Freundlich model. This newly synthesized biopolymer proved to be a chemically useful material for cations removal from aqueous solution.

Abstract:The cellulose matrix was characterized by FTIR, 13 C NMR, XRD, TG, SEM and applied in the removal of the reactive red RB dye in an aqueous medium, with a capacity of adsorption at a pH of 2.0, and an adsorption equilibrium time which was reached at around 200 mins. The kinetic study for the system followed the Elovich model. The adsorption isotherms for the system at temperatures of 35°C, 45°C, and 55°C were adjusted to the Langmuir, Freundlich, Sips, and Redlich-Peterson non-linear models, with a capacity of adsorption for adsorbent of 5.97 mg g , respectively. The adsorption occurred by electrostatic interactions and it was favorable and spontaneous, with the influence of temperature.

Hybrid pigments based on organo-saponite (cetyltrimethyl ammonium bromide (CTAB-Sap) and a commercial anthocyanin (ACN) dye, Crystal Red Grape, were prepared. The interactions between organic dye guest and hosts (including saponite and organo-saponite) were investigated by X-ray diffraction, transmission electron microscopy and Fourier transform infrared spectroscopy. The pigments exhibit different colors function of their host-guest interactions. The blue color of organo-clay-anthocyanin indicates the stabilization of quinoidal base form of the dye. The hybrids have good stability against visible light irradiation and basic pH conditions. These dyed materials are environmentally friendly and can be promising candidates in different application fields.

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Considering the challenges of urea administration due to the high ureolytic activity of the rumen and the importance of its use, as well as taking into account the relevance of sustainably exploiting the technological potential of biodiversity, this research studies the encapsulation of urea in different clay minerals (palygorskite (Pal), sepiolite (Sep), and Veegum® (V)) as an alternative for use as nonprotein nitrogen (NNP) sources. A method of incorporation was developed in which the encapsulation of urea was proven by X-ray diffraction; fibrous materials, Pal and Sep had similar characteristics due to the decrease in the relative plane intensity (011), suggesting a decrease in the order of their stacking due to the presence of urea on the surface or inside channels. By contrast, V showed a 7.74° reflection shift, suggesting an increase in basal spacing from 11.45 Å in V to 14.88 Å in the sample after urea encapsulation. By thermogravimetry, it was observed that the presence of urea did not change the mass-loss profiles but only increased the percentage of loss in respective events, indicating urea incorporation in the clay minerals. These results provide a promising alternative for administering NNP sources in the ruminant diet.

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