Removal of Yellow F3R, Di Maria Brilliant Blue R and Reactive Brilliant Red M-3BE from Aqueous Solutions by a Rapid and Efficient Ultrasound-Assisted Process with a Novel Biosorbent of Cottonseed Cake: Statistical Modeling, Kinetic and Thermodynamic Studies

Abstract

Cottonseed cake as a domestic feed and a by-product of textile industry was utilized as a novel adsorbent for the decolorization of Yellow F3R (YF3R), Di Maria Brilliant Blue R (DBBR) and Reactive Brilliant Red M-3BE (Red F3B) aqueous solutions based on a rapid and efficient process of ultrasound-assisted adsorption. This study aimed to model the effects of the five factors on decolorization efficiency by response surface methodology: temperature, initial pH, reaction time, concentrations of initial dyestuff and adsorbent. A Box–Behnken design with five factors at three levels was used to set the experimental schedule. The maximum decolorization efficiency was obtained consistently at the lowest initial pH (2), the highest reaction time (30 min) and adsorbent concentration (1.5 g/L). Analysis of variance and the best-fit multiple nonlinear regression models were cross-validated (R2pred) accounting for 90.03–93.94 % of variation in decolorization efficiency. The decolorization of YF3R, DBBR and Red F3B on cottonseed cake fitted well pseudo-second-order kinetic mechanism and Langmuir isotherm and it was found to be of endothermic and spontaneous nature.