Removal of chromium(III) ion from tannery wastewater and river water using natural and activated orange peel

Abstract

In this study, the adsorption method was used to explore the removal of chromium(III) ion from chrome liquor that remained after chrome tanning in tannery and from the Buriganga River water as well. Both the natural and activated orange peel powder were used as adsorbents owing to its inexpensive and eco-friendly nature. In order to establish the best adsorption conditions, adsor-bent concentration 5–40 g/L, pH 2–8 and contact time 30–120 min were investigated for Cr(III) removal from aqueous solutions using both natural orange peel and activated orange peel. Characterization of the adsorbents were done by using thermogravimetric analysis and Fourier-transform infrared spectroscopy analysis. The equations for both the Langmuir and Freundlich models were implemented to analyze the equilibrium data. Furthermore, the pseudo-first and sec-ond-order kinetic models were also utilized to evaluate the kinetic data. Both the natural and activated orange peel were found to remove a maximum of 77% and 96% of chromium(III) ion, respectively.