Optimization of adsorption conditions for Acid Chrome Blue K removal from aqueous solution using sugar-based activated carbon: Equilibrium isotherms and kinetics modeling

Abstract

In this study, white sugar was dehydrated and then activated, producing extremely porous carbon as a result. The activated sugar-based carbon (ASC) was prepared by first dehydrating white sugar to produce dehydrated sugar carbon (DSC) which was then chemically activated in a nitrogen atmosphere using NaOH as activating agent. With the aid of central composite design (CCD), a component of response surface methodology (RSM), the ideal circumstances for the removal of Acid Chrome Blue K (ACBK) dye onto the ASC adsorbent from aqueous solution were investigated. Adsorbent dosage of 0.60 g, initial concentration of 79 mg/L and shaking speed of 258 rpm were the ideal adsorption conditions attained. The obtained experimental and predicted values were 94.89% and 94.22%, respectively, demonstrating good agreement between the experimental and predicted values from the model with only a modest error of 0.71. The linearized Langmuir equations in five different versions, as well as the Freundlich and Temkin adsorption isotherms, were used to simulate the adsorption data. Chi square (χ²) and the correlation coefficient (R²) were taken into consideration while assessing the validity of each isotherm model to support the selection of the best adsorption model. The equilibrium adsorption data were best represented by the order Langmuir-2 > Freundlich > Temkin isotherms. The outcomes showed that the best model for describing the kinetics data was pseudo-second-order.