Abstract:
In this study, microcrystalline cellulose (MCC) was utilised as an adsorbent for the removal of Cr(VI) from
synthetic wastewater. FTIR spectroscopy confirmed the main characteristic infrared absorption bands of
cellulose in the MCC. The MCC had a relatively low BET-specific surface area of 2.05 m2 g-1. SEM revealed that
the MCC had a short-fibre, rod-shapedmorphology. XRD analysis confirmed the MCC semi-crystalline structure.
Batch adsorption studies showed that the optimal conditions for the removal of Cr(VI) from the wastewater using
the MCC were an initial Cr(VI) concentration of 10 mg L-1, an adsorbent dosage of 20 g L-1 and a Cr(VI) solution
pH of 1. The MCC required 96 h to reach equilibrium, and the equilibrium removal efficiency was 83 %. The
point of zero charges of the MCC (pH 6.2) and occurrence of Cr(III) in solution during the adsorption process
suggests that the Cr(VI) removal mechanism from the wastewater by the MCC was adsorption coupled by
reduction. The pseudo-second-order (PSO) model provided the best fit for the experimental kinetics data. The
Freundlich isotherm provided the best fit to the experimental equilibrium data. Compared to commercial
adsorbents, the adsorption capacity of the MC was relatively low at 3.92 mg g-1.
