عنوان مقاله [English]
Derivative spectrophotometric and Taguchi orthogonal design was used for determination and optimization of simultaneous removal of Direct red and Reactive black by Cobalt ferrite nano-particles modified with PDA from an aqueous solution in a batch system. Cobalt ferrite nano-particles were prepared using the co-precipitation method. The sorbent was characterized by FT-IR spectroscopy, SEM, and XRD techniques. Effective factors on adsorption process, such as amount of sorbent, initial concentration of dyes, pH value, and time were considered using a L16 Taguchi orthogonal array design. Taguchi analysis is based on choosing the best run by analyzing signal-to-noise ratio (S/N), whose form depends on the experiment objective. Thus, the removal percentage (R%) and capacity uptake (q) of dyes were transformed into an accurate S/N ratio for a “high is better” response. The best conditions for adsorption of dyes were determined by the Taguchi method and desirability approach as pH = 3, sorbent dose of 10 mg , initial reactive black concentration of 200 mg L−1, initial Direct red concentration of 200 mg L−1, and contact time of 4 min.