Removal of reactive black 5 from aqueous solution using chitosan beads: optimization by Plackett-Burman design and response surface analysis

摘要

Contaminations due to dyes pose not only a severe public health concern, but also many serious environmental problems. The present project aims to prepare an inexpensive and efficient sorbent that could remove dyes that are commonly used in the industry. Chitosan has been seen as a promising sorbent due to its significant properties, such as biocompatibility, biodegradability and non-toxicity. Batch studies were performed under various experimental conditions and the parameters studied included pH, contact time, initial concentration and agitation rate. The kinetics of dye sorption fitted a pseudo-second-order rate expression. Equilibrium data could be fitted into both Langmuir and BET isotherms. Plackett-Burman design was applied to identify the most significant factors in the removal of Reactive Black 5 (RB5) by chitosan. The effect of operating parameters on RB5 uptake was studied and a mathematical model showing the influence of each variable was obtained. The interaction between the factors and their optimum levels for maximum percentage uptake of RB5 were determined using Response Surface Methodology. The optimum sorption conditions were determined as initial pH 7.00 and at contact time greater than 200 min.