Phosphoric Acid and Cashew Bark Extract Activated Carbons derived from Coconut (Cocos nucifera) Shells for Cr (VI) Adsorption

Document Type : Original Article


1 Department of Chemical Sciences, College of Sciences, Afe Babalola University, Ado - Ekiti, Nigeria

2 Department of Chemistry, Covenant University, P.M.B. 1023, Ota, Nigeria


THIS study was conducted to activate and characterize carbons prepared from coconut shells for subsequent adsorption of Cr (VI) from synthetic wastewater. The adsorption process was carried out through batch studies. The results showed that the process was pH, contact time and temperature dependent. The optimum pH for Cr (VI) adsorption was 2 for both cashew bark extract activated (CNAC1) and H3PO4 activated (CNAC2) carbons. Characterization of the activated carbons using Fourier Transform-Infrared Spectroscopy (FTIR) revealed that OH and C=O were some of the prominent functional groups involved in the adsorption of Cr (VI). The EDX analysis results confirmed the adsorption of Cr (VI) on the surfaces of the activated carbons (ACs). Furthermore, SEM characterization showed that the free ACs were coarser and more porous than their Cr (VI loaded counter-parts while elemental composition of the activated carbons showed that the samples were carbonaceous. The adsorption process was feasible and followed pseudo-first-order kinetic model. Generally, the efficiency of CNAC2 was higher than that of CNAC1. However, cashew bark extract could be used as an activating agent for the preparation of activated carbon from coconut shells for Cr (VI) adsorption because it is cheaper and eco-friendlier than H3PO4.


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