Characterization of surface properties of chitosan/bentonite composites beads by inverse gas chromatography

Chitosan/bentonite (CSBt) composites beads were prepared by dropwise of a solution containing chitosan and bentonite to an alkaline NaOH solution. Fourier Transform Infrared Spectroscopy, X-ray diffraction analysis, X-ray photoelectron spectroscopy, XPS and Brunauer-Emmett-Teller BET analysis have been used to provide new insights on the composition and morphology of CSBt composites beads surface. In this study, inverse gas chromatography (IGC) was implemented to characterize physico-chemical properties of CSBt composites surface. IGC at infinite dilution (IGC-ID) was used to understand the effect of CS on dispersive component of the surface energy of the bentonite. The increasing amount of CS leads to significantly decrease of Bt gamma(d)(s) emphasizing the Bt coating with CS. The IGC at finite concentration ( IGC-FC) was also implemented allowing us to reach several parameters such as: specific surface area with organic probes and the distribution functions of the adsorption energy sites on the solid surface. In this case, the most significant decreases were observed in the specific surface area obtained with the octane and isopropanol probes. The distribution function of the adsorption energy sites obtained with isopropanol revealed the decrease in the number of the high energy sites with increase of CS/Bt mass ratio. (C) 2020 Elsevier B.V. All tights reserved.

Automated summary

Chitosan/bentonite composites beads were prepared and characterized using various techniques to study their surface composition and morphology, highlighting the influence of chitosan on bentonite surface. Inverse gas chromatography was utilized to analyze the physico-chemical properties, showing significant effects of chitosan on the dispersive component of the bentonite surface energy.