Ipomoea aquatica roots as environmentally friendly and green adsorbent for efficient removal of Auramine O dye

Abstract

This study presents Ipomoea aquatica root (“kangkong” root or KR) as a plausible environmentally friendly adsorbent. This readily available adsorbent, after oven drying, demonstrates strong adsorption characteristics toward Auramine O (AO) dye exhibiting 2.0 h equilibration time and stable efficiency within a sufficiently broad range in both pH and ionic strength. Adsorption kinetics was best described by the pseudo second order and Elovich models, indicating that chemisorption of two reactive moieties could be involved. Application of the experimentally obtained adsorption equilibrium data to investigate the conformity among many adsorption isotherm models, namely Langmuir, Freundlich, Temkin, Redlich-Peterson and Sips, together with corresponding error analyses, identified that the Sips model be the best-fit model, leading to attractive maximum adsorption capacity of 455.74 mg g−1. Further, regeneration and reuse of the spent adsorbent would be possible with ~ 75% AO dye being adsorbed even at the 5th cycle, when using base treatment. Hence, the utilization of Ipomoea aquatica root as a low-cost, effective adsorbent in wastewater treatment could be possible.