Inverse gas chromatographic characterization of halloysite-carbon composites as adsorbents for skin disinfectants from water solutions

The influence of physicochemical parameters of halloysite-carbon composites on the adsorption of skin disinfectants was investigated. The dispersive surface free energy and acid-base properties of halloysite-carbon composites were determined using inverse gas chromatography. The free adsorption energy was higher for all halloysite-carbon composites compared to the unmodified halloysite, which acted as a less electron-donating adsorbent. In contrast, the composite obtained using halloysite nanotubes (HNT) and ground microcrystalline cellulose as the carbon precursor exhibited the highest free adsorption energy and the Kb/Ka ratio. These results suggest that the free adsorption energy can be an additional factor influencing the adsorption process. We demonstrated that the composite with the highest free adsorption energy is effective for removing triclosan, chloroxylenol and chlorophene from water. The acid-base properties of halloysite-carbon composites enhance the adsorption of these compounds due to their acidic character. The composite with the highest Kb/Ka ratio removes adsorbates from aqueous solutions with the greatest efficiency. Parameters such as free dispersion energy, electron-donating, or electron-accepting properties of the adsorbent help explain why these composites exhibit high adsorption capabilities.