Adsorption of cadmium (II) on organic xerogel microspheres: effect of adding sepiolite or vermiculite and operating conditions on the adsorption capacity.

The organic xerogel (OX) was synthesized through sol-gel polymerization of formaldehyde and resorcinol in inverse emulsion using Na2CO3 as a catalyst. Meanwhile, OX containing sepiolite (OX-Sep) and vermiculite (OX-Ver) were prepared similarly to OX but adding clays during synthesis. All materials were mesoporous and presented spherical morphology, and the surface of these materials exhibited an acidic character because the concentration of acidic sites was higher than those of basic sites. Cd(II) adsorption from aqueous solutions onto OX, OX-Sep, and OX-Ver was examined, and the OX-Sep showed the highest adsorption capacity towards Cd(II) of 189.7 mg/g, being 1.5, 2, and 36 times higher than that of OX-Ver, OX, and Sep. The OX-Sep capacity for adsorbing Cd(II) was significantly lessened by decreasing the pH from 7 to 4 and raising the ionic strength from 0.01 N to 0.1 N. This trend was ascribed to electrostatic attraction between the Cd+2 in water and the negatively charged surface of OX-Sep. Besides, desorption studies at pH 4 showed that the average desorption percentage of Cd(II) adsorbed on OX-Sep was 80%. The characterization results and the effect of the operating conditions on the adsorption capacity proved that electrostatic attraction and cation exchange play a crucial role in the adsorption mechanism.

Clay Mineral Minerals as a Strategy for Biomolecule Incorporation: Amino Acids Approach.

The potential use of amino acids by ruminal microorganisms converting them into microbial protein for ruminants makes it challenging to supplement these nutrients in an accessible form in animals' diets. Several strategies to protect amino acids from ruminal degradation were reported, producing amino acids available for the protein used in the intestine called "bypass." The intercalation of biomolecules in clay mineral minerals has gained notoriety due to its ability to support, protect, transport, physicochemical properties and non-toxicity. This study aimed to investigate the incorporation of L-lysine (Lys), L-methionine (Met), and L-tryptophan (Trp) amino acids in the clay minerals sepiolite (Sep) and Veegum® (Veg) using the adsorption method. The characterization techniques of X-ray diffraction and infrared spectroscopy indicated the presence of biomolecules in the inorganic matrices. Elemental and thermal analyzes monitored the percentages of incorporated amino acids. They showed better incorporation capacities for Veg, such as Met-Veg < Lys-Veg < Trp-Veg and Lys-Sep < Met-Sep < Trp-Sep for sepiolite, except for the incorporation of Met. Matrices provide a promising alternative for planning the administration of biomolecules, using essential amino acids as models, and may offer an alternative to improve functional diet strategies.

Determination of effects of some pelletted straws on rumen pH and temperatures with wireless rumen sensors / Determinación de los efectos de algunas pastillas peletizadas en el rumen pH y temperaturas con sensores de rumen inalámbricos

ABSTRACT Objective. This study was conducted with the aim of determination of the effects of pellets prepared with addition of different additives (molasses, guar meal and sepiolite) on changes in in vitro rumen pH and temperature. Materials and methods. In the current study sixteen pelleted feeds were prepared with wheat and soybean straws. The Daisy incubator was used for maintaining (mimicing) rumen conditions and feed was incubated for 48 hours. The wireless rumen sensors were used for determination of the changes in in vitro rumen pH and temperature. The data were subjected to one way variance analysis. Results. The tested boluses were found to show similar temperature and pH measurements to digital pH metre measurements. The effect of sepiolite addition on pH and temperature was found insignificant in all treatments. The lowest pH value was determined for wheat straws. Control groups and molasses added in soybean straws and wheat straws were similar in terms of ruminal pH values. Guar meal and guar meal+molasses added in soybean straws was shown to increase pH (p<0.01). In vitro rumen temperatures in soybean straws were found lower compared to those in wheat straws in all treatments (p<0.001). Conclusions. It was concluded that boluses integrated to Daisy incubator can be safely used for determining the effects of feeds on rumen fermentation in in vitro studies.

RESUMEN Objetivo . Este estudio se realizó con el fin de determinar los efectos de los pellets preparados con adición de diferentes aditivos (melaza, harina de guar y sepiolita) sobre los cambios en el pH y temperatura in vitro del rumen. Materiales y métodos. En este estudio, se prepararon dieciséis alimentos peletizados con pajas de trigo y soya. La incubadora Daisy se usó para mantener (imitar) las condiciones del rumen y la alimentación se incubó durante 48 horas. Los sensores de rumen inalámbricos se usaron para la determinación de los cambios en el pH y la temperatura in vitro del rumen. Los datos fueron sometidos a análisis de varianza de una vía. Resultados. Se encontró que los bolos evaluados muestran mediciones de temperatura y pH similares a las mediciones del medidor de pH digital. El efecto de la adición de sepiolita sobre el pH y la temperatura fue insignificante en todos los tratamientos. El valor de pH más bajo se determinó para pajas de trigo. La adición de grupos de control y melazas en pajas de soya y paja de trigo fue similar en términos de valores de pH ruminal. Se demostró que la adición de harina de guar y harina de guar + melazas en pajas de soya aumenta el pH (p <0.01). Las temperaturas in vitro del rumen en las pajuelas de soya fueron menores en comparación con las pajas de trigo en todos los tratamientos (p <0.001). Conclusiones. Se concluyó que los bolos integrados a la incubadora Daisy se pueden utilizar de forma segura para determinar los efectos de los alimentos en la fermentación ruminal en estudios in vitro.