Comparison between Various Adsorbents for Direct Blue Dye 14 Removal from Aqueous Solution

Abstract

In this work, the adsorption potential of various adsorbents was investigated in batch mode study. Polyaniline (PAn) and its nanocomposites were prepared using a novel synthesis method and then used as an adsorbent for removal of direct blue dye 14 (DB14). The results were compared with frequently used adsorbents granular activated carbon (GAC) and powder activated carbon (PAC). Furthermore, the combination of PAn and porous carbon adsorbents was examined. Adsorbents that stand out for high removal efficiency are PAn, polyaniline/hydroxypropylcellulose (PAn-HPC), and polyaniline/polystyrene (PAn-PS). The results indicate that PAn-PS was an attractive candidate for direct blue dye removal. Therefore, present work focuses on utilization of PAn-PS nanocomposite as an efficient adsorbent for DB14 removal in a batch adsorption system. PS core particles were prepared in microemulsion system and further coated with PAn by in situ polymerization method. The core-shell structure of PAn-PS was confirmed with a field emission scanning electron microscope (FESEM). Experiments were carried out as a function of pH, contact time, initial dye concentration, and adsorbent dosage. The adsorption kinetics was found to follow the pseudo-second-order model. The applicability of the Freundlich and Langmuir models was investigated and the equilibrium data were fitted well with the Langmuir model. Design of experiment was used in order to evaluate the interaction effects of all the parameters and analysis of variance (ANOVA) test was used to check the significance of the model. The results demonstrated that PAn-PS can act as an appropriate adsorbent for DB14 removal from aqueous solution.