Study of loading isothiazolinone-based biocide and release profiles from mesoporous silica matrices

ANDREA M. PEREYRA; M. SOLEDAD LEGNOVERDE; LUCAS E. MARDONES; ELENA I. BASALDELLA

Sitges

Conferencia; 7th International Colloids Conference; 2017

Silicamesoporous materials were proposed as new hosts for stabilizingisothiazolinone-based biocides. We synthesized two types of porous matrices:SBA-15 silica and mesocellular siliceous foam (MCF). The physicochemicalproperties of the silicas (structure, textural properties) are evaluated inorder to determine their ability to encapsulate, stabilize and subsequentlyrelease, a commercial biocide used for latex preservation (CMIT/MIT). CMIT/MIT consistsof an aqueous solution of the active ingredients CMIT (5-chloro-2-methyl-4-isothiazolin-3-one)and MIT (2-methyl-4-isothiazolin-3-one), present in a CMIT/MIT: 3/1 weightratio. The two matrices were loaded with different biocide concentrations byusing the traditional incipient wetness impregnation method. N2 adsorption,SEM and FTIR analyses showed that the biocide can be encapsulated within silicaframeworks and preserved its original structure. Release tests in aqueous mediaindicated that the CMIT/MIT concentration in the leaching solution depends onthe matrix nature, being the smaller values obtained when ordered matrices wereused. Desorption experiments indicated that the biocide delivery in aqueousmedia could be delayed by increasing the pH of test solutions. Results showedthat biocide encapsulation allows maintaining a long-lasting release,preserving the biocide activity even under conditions of temperature and pH atwhich decomposition and hydrolysis of non-supported CMIT is observed.