Mechanism of adsorption of actives onto microporous functionalised calcium carbonate (FCC)

Charlotte L Levy,Joachim Schoelkopf,Andrew Turner,Samuel Beckett,Giuliano M Laudone,G Peter Matthews,Patrick A C Gane

doi:10.1007/s10450-017-9880-7

Charlotte L Levy, Joachim Schoelkopf + Show 5 more

Open Access

https://doi.org/10.1007/s10450-017-9880-7

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Abstract

Microporous ‘functionalised’ calcium carbonate (FCC) has potential for use as a carrier for the controlled release of ‘actives’, by permeation and diffusion. We have investigated the nature of the FCC surface and the mechanism of adsorption of two typical actives, namely the anti-inflammatory drug aspirin and the flavour compound vanillin, from chloroform and aqueous ethanolic solutions. There is indirect evidence from the quantitative perturbation of Toth isotherms that their adsorption is hindered by a stagnant diffusion layer of water trapped in the micro-porosity of the FCC. To complement previous studies of the surface of FCC, it was also tested with the cationic probe benzyltrimethylammonium bromide and the anionic probe sodium 2-naphthalenesulphonate. Experimental procedures were validated by comparison with adsorption onto ground calcium carbonate and high surface area talc.

Highlights

IntroductionThis work is a study of the adsorption properties of dissolved organic species onto ‘functionalised’ calcium carbonate (FCC)
1.1 Functionalised calcium carbonateThis work is a study of the adsorption properties of dissolved organic species onto ‘functionalised’ calcium carbonate (FCC)
FCC surface was tested with the cationic probe benzyltrimethylammonium bromide (BTMAB) and the anionic probe sodium 2-naphthalenesulphonate (Na2NS)

Summary

Introduction

This work is a study of the adsorption properties of dissolved organic species onto ‘functionalised’ calcium carbonate (FCC). FCC comprises particles with intraparticulate porosity, which is microporous according to the pore size classification of Mays (2007). The adsorbates were the anti-inflammatory drug aspirin and the flavour compound vanillin, in chloroform and aqueous ethanolic solutions. The. FCC surface was tested with the cationic probe benzyltrimethylammonium bromide (BTMAB) and the anionic probe sodium 2-naphthalenesulphonate (Na2NS). Sized particles of ground calcium carbonate (GCC) were used as a (null) control adsorbent. Finnish talc with a high surface area was used as a control to check the methodology of measuring the (null) adsorption of BTMAB onto FCC

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