Removal of chromium from aqueous solutions using a palm kernel shell adsorbent

The presence of chromium (VI) or its compounds in water is a result of its uses in modern society. The presence of toxic chromium (VI) in large quantities will adversely affect and interfere with many beneficial uses of water. Adsorption is an effective approach used to remove chromium (VI). Chemical characteristics of the palm kernel shell (PKS) were optimized by hydroxyl pretreatment followed by quaternization for the adsorption of chromium (VI). It was observed that the chemically modified palm kernel shell (CMPKS) showed an effective adsorption property, with a maximum capacity of 19 mg/g at pH 2 and 17 mg/g at pH 6 and 4. The kinetics model with pseudo-first and pseudo-second orders were studied, along with Langmuir and Freundlich isotherms. The Langmuir model and the pseudo-second-order model were observed to be a better fit for this process. Scanning electron microscopy analysis showed significant changes in the surface morphology of CMPKS, with changes in the projection and porous surfaces.