CARACTERIZACIÓN Y COMPARACIÓN DE LA ADSORCIÓN DE CLORURO DE CETILPIRIDINIO EN DOS MONTMORILLONITAS

F. YARZA; A.M. FERNÁNDEZ SOLARTE; S. YAPAR; G. ÖZDEMIR ; R.M. TORRES SÁNCHEZ

Congreso; II Congreso Internacional de Ciencia y Tecnología Ambiental. II Congreso Nacional de la Sociedad Argentina de Ciencia y Tecnología Ambiental; 2015

SACYTA

Due to the serious concern that causes microbial contamination in food industry and infection for medical applications, the development of bactericide materials is of great interest. In a previous work1, the bactericide capacity of Cetylpiridinium chloride (CP) against Staphylococcus aureus was sorbed on a Montmorillonite (Mt) from Middle Anatolia, Turkey, generating a material with favorable characteristics (laminate and hydrophobic) for different technology applications (e.g. plastic industry). In addition, this product is more valuable than the raw mineral.    The purpose of this work was to characterize two Mts and its exchanging products. The Mts were native from Río Negro, Argentine (Mt-A) and from Turkey (Mt-T), mentioned above. Mt-A and Mt-T were characterized by: Zeta Potencial, thermal analysis, Apparent diameter (Dapp) 650nm, pH in water 7.0, Specific surface area (SBET ) 34 and 73 m2/g, XRD d001 peaks: 11.6 and 10.5 nm, respectively. Both raw samples had closed CEC (0.825 and 0.91 meq/g) and the mineralogical content was: 4, 12 and 84% Quartz, Feldspar and Mt, for Mt-A; and 3, 1 and 96% Cristobalite, Calcite and Mt, for Mt-T.    Two products were prepared exchanging CP with 50% of the cation exchange capacity (CEC) to each raw Mt, this percentage had being previously determined as the minimum quantity of CP necessary to maintain bactericide capacity in Mt-T1. The percentage amounts of CP exchanged were: 13.0 and 13.9 % for Mt-A-CP and Mt-T-CP, respectively, which produced a shift in the d001 peak of 0.31 and 0.37 nm respects to the corresponding raw samples, indicating an entry of CP to the Mts interlayers. Thermal analysis for Mts revealed two classical peaks, one below 200°C assigned to a dehydration process of the external surface and interlayer space, and a second one at 669°C attributed to the dehydration of hydroxyl groups. The CP addition produced an increase around 7 % mass loss in the range from 200 to 550 °C assigned to the CP decomposition2. Analysis of Zeta potential curves (pH 2 to 10 range) indicated a decrease of negative charge in Mt-A-CP sample respect to Mt-A, while no variation in external charge was found between Mt-T-CP and Mt-T samples.These results indicate that although the amount of CP exchanged was similar in both Mts, in Mt-A both interlayer and external sites interacted with CP, while in the Mt-T the interlayer sites are mainly used to bond CP