Adsorption of Isothiazolinone-Based Biocides onto Ordered Mesoporous Silica

M. SOLEDAD LEGNOVERDE; SANDRA S. SIMONETTI; LUCAS E. MARDONES; ELENA I. BASALDELLA

Workshop; VI International Workshop on Oxide-based Materials; 2016

Mesoporous silica SBA-15 particles were synthesized in order to evaluatetheir effectiveness as encapsulating agents for a commercial biocide composedof a mixture of methylisothiazolinone and chloromethylisothiazolinone(MIT/CMIT).  Four powdered samples ofsilica particles having different textural properties, sizes and morphologieswere hydrothermally obtained and afterwards characterized by SEM, TEM, SAXS,and nitrogen adsorption?desorption measurements. Adsorption of the biocide onthe prepared materials was investigated, and the results showed that adsorptioncapacities increase as the particle size becomes smaller. Higher biocideamounts were also retained on particles having increased pore size and porevolume. Additionally, a most probable interaction mechanism between MIT/CMITand SBA-15 is proposed on the basis of molecular modeling calculations. Thetheoretical approach indicates that two adsorption geometries with comparableminimum levels of strength can be adopted by the biocide: planar adsorptionwhen the biocide molecule rings are adsorbed on the silica surface and verticaladsorption when the O atom of the MIT/CMIT interacts with the H atom ofsilanols. .