Activated carbon with high sorption potential prepared from Cereus pterogonus cactus stems for environmental remediation

Cacti have unique structure and properties and are sustainable plants requiring minimum resources to grow. The genus Cereus is among the most common of about 1700 species of cactus in the world, in which Cereus pterogonus (circular cactus) is ubiquitous. In this study, the outer sheath in cacti was separated and converted into carbon with and without activation. Activation with KOH provided carbon with substantially high surface area (873 m2/g) and porosity. This activated carbon was used as a sorbent to remove methylene blue from water under various sorption conditions. The dye sorption process was endothermic and spontaneous based on the thermodynamic analysis. The maximum adsorption of 399 mg of dye per gram of activated carbon even at a high initial dye concentration of 140ppm was obtained, considerably higher than previous reports on using activated carbon prepared from biomass for removal of methylene blue.