Adsorption of orange G using activated carbon derived from common reed (Phragmites australis) in Mekong Delta, Vietnam

Abstract

Activated carbon (AC) fabrication using agricultural waste biomass has been considered economical and sustainable. In this study, common reed (Phragmites australis)-derived activated carbon (CRPa-AC) was prepared via two consecutive stages, including pyrolysis and activation using K2CO3 and employed as an absorbent for orange G (OG) removal. The CRPa-AC prepared at 1073 K and the K2CO3/char weigh ratio of 1.5 had the surface area = 549.7 m2/g and exhibited the removal efficiency of OG = 91.8%. The pseudo-second order kinetic and Langmuir isotherm models accurately described the adsorption of OG on the CRPa-AC. The maximum adsorption capacity of CRPa-AC (77.5 mg·g−1) surpassed that of other biomass-based AC previously published. Thermodynamic studies suggested that the OG adsorption on the CRPa-AC surface is endothermic. The good reusability of CRPa-AC after three regeneration cycles enabled its practical use in the OG removal. This study provided a typical example of converting waste into valuable material for wastewater treatment.