Functionalization, Uptake and Release Studies of Active Molecules Using Halloysite Nanocontainers

Abstract

Halloysite nanotubes are inorganic clay minerals of kaolin group. Halloysite possess unique morphology, chemical composition, cation exchange capacity and charge properties making them ideal candidate for various industrial application. In the present study, an attempt was made to functionalize the exterior surface of halloysite nanocontainer. The surface of halloysite nanocontainer was modified using tetrabutylammonium chloride (TBAC). Further an attempt was made to employ these functionalized nanocontainers to uptake and release the active molecule (dye Acid Red1). TBAC-modified nanocontainer indicated higher adsorption capacity of 4.54 mg/g as compared to unmodified nanocontainer (3.08 mg/g). The release behaviour of active molecule from loaded nanocontainers was found with change in pH and temperature. Since the loading characteristics of functionalized nanocontainers were found to be adsorption dependent, parameters such as effect of time, loading, pH, initial concentration were studied for analysing the loading characteristics. The dye release from 0.5 g dye-loaded TBAC-modified nanocontainers at pH 11 and at 32 °C was found to be 92%. Lastly, the release readings were analysed for the best fit (97%) using permeation kinetic model (Peppa’s model).