Removal of Congo red from aqueous solution in single and binary mixture systems using Argan nutshell wood

Abstract

Purpose: Argan nutshell wood (ANW) has been used in this study as an agricultural solid waste to remove Congo red (CR) from an aqueous solution in single and mixture binary in the presence of methylene blue (MB) or crystal violet (CV). Design/methodology/approach: The ANW was characterized by Fourier transform infrared and scanning electron microscope analysis. The effect of ANW dose (8–40 gL−1), contact time (0–180 min), pH of the solution (4–11) and CR dye concentration (100–500 mgL−1) on CR adsorption was studied in batch mode and evaluated by kinetic and isotherm models in a single system. In the binary system, the CR removal was studied from a CR + MB and CR + CV mixture with different percentages of dyes, ranging from 0% to 100%. Findings: The pseudo-second-order and the Langmuir models could best describe the CR sorption onto ANW in a single system. In addition, in the case of the binary system, there is the appearance of a synergistic phenomenon between the CR and the other cationic dyes and the CR adsorption capacity increased until 12.24 mg g-1 and 12.06 mg g-1 in the presence of the MB and CV in the mixture, respectively. Practical implications: This study demonstrated that ANW prepared can be suggested as an excellent potential adsorbent to remove dyes from wastewaters from single and mixture systems. Originality/value: This study is original.