Kinetic, Isothermal and Thermodynamic Study on the Removal of Hexavalent Chromium with Biocomposites (Cellulose–PLA)

Abstract

Currently, water is being polluted via various anthropogenic activities, resulting in wastewater contaminated with multiple pollutants, including heavy metals. Hexavalent chromium is a toxic heavy metal that poses significant health risks upon exposure. Biocomposites are materials that are partially composed of organic substances that enhance different properties of a composite. The aim of this study was to evaluate the kinetic, isothermal, and thermodynamic behaviour of a cellulose-based biocomposite with polylactic acid (PLA) for the removal of Cr (VI) from synthetic water. The results indicated that the Freundlich and Elovich models provided the best fit for the isothermal and kinetic data, with R2 values of 0.671 and 0.973, respectively, suggesting that the adsorption process was chemical in nature and occurred on a heterogeneous, multilayer surface. Additionally, the thermodynamic analysis revealed that the adsorption process was exothermic, irreversible, and non-spontaneous. This study presents an innovative approach to the removal of metal ions using a cellulose–PLA biocomposite for wastewater treatment, offering kinetic, isothermal, and thermodynamic data applicable to the adsorption of other heavy metals.