Chemical Regeneration of Activated Carbon from Cocoa Pod Shells

Restore activated carbon by eliminating the methylene blue previously adsorbed on the adsorbent. With a view to protecting the environment, a global concern, this study carried out using carbon from cocoa pod shells. In Côte d'Ivoire, around 1.9 million tonnes of cocoa sold every year, and cocoa farming generates between 13 and 15 million tonnes of waste, mainly cocoa shells. Like many agricultural wastes, cocoa shells transformed into activated carbon. Before pyrolysis, the shells were ground, sieved and impregnated with orthophosphoric acid. The activated carbon obtained is in powder form. For the purposes of this study, before desorption, the activated carbons were initially saturated with MB. For this adsorbent regeneration study, chemical desorption was used. In the context of chemical regeneration, these saturated coals brought into contact with a sodium chloride (NaCl) solution and then stirred. To follow the evolution of desorption, the spectrophotometer was used to measure the concentration of methylene blue resorbed. The desorption tests showed a remarkable elimination from the first 10 minutes. The desorption kinetics comprises two phases: a rapid kinetics between 0 and 30 minutes and a slow kinetics between 30 and 60 minutes. Desorption of the dye reaches a concentration equal to 0.84 mg/l at pH = 4 at temperature =80°C. For modelling, the coefficient of the Langmuir II model is greater than or equal to O.9893. The model of Langmuir III is less than or equal to O.9373. The Freundlich model coefficient is 0.9842 or less. Desorption therefore takes place on adsorption sites that are energetically homogeneous and without interaction between the adsorbed cations of the dye. Experimental parameters such as pH, temperature and concentration of sodium chloride (NaCl) solution influence Desorption of MB. The model of Langmuir II describes well the process of desorption of the MB.