RESUMEN
Cocoa shell was modified whit sodium hydroxide (NaOH) and cationic surfactant cetyltrimethylammonium bromide (CTAB) to increase surface functionality, surface area, and positive charge density. The prepared adsorbent CC-OH-CTAB was used to remove indigo carmine (IC) and bromocresol green (BCG) dyes from water. The optimal pH for IC and BCG adsorption were 2 and 4, respectively. The equilibrium was attained after a contact time of 30 min for IC and 120 min for BCG. The maximum adsorption capacity (Qmax) of IC and BCG obtained was 85.1 mg g-1 and 192.7 mg g-1, respectively. The Liu isotherm model best described the equilibrium results. The adsorption kinetics model showed that IC and BCG adsorption onto CC-OH-CTAB followed the pseudo-first-order and pseudo-second-order model, respectively. The regeneration and reusability experiments indicated that CC-OH-CTAB had much stability and excellent performance meanwhile repeatedly used. Finally, the insertion of CTAB on the CC-OH surface proved to be an excellent way to improve the adsorption performance of this material concerning dyes.
