A spectroscopic study for understanding the speciation of Cr on palm shell based adsorbents and their application for the remediation of chrome plating effluents

► Palm shell based adsorbents were prepared under different thermochemical conditions. ► Removal of Cr proved to be more effective with adsorbent prepared at 150 °C. ► Adsorption coupled reduction of Cr(VI) was demonstrated by XPS. ► Cr(III) remained adsorbed effectively even at pH 1. ► The adsorbents showed potential for removal of Cr from chrome plating effluents.