Influence of Some Preparation Parameters on The Efficiency of Activated Carbons Prepared from Teak Wood Shavings (Tectona Grandis) and Coconut Shells (Cocos Nucifera) for The Treatment of Industrial Wastewater

Abstract

In this work, we valorized two wastes of plant origin in activated carbon (AC) by chemical activation, with a view to their use for the elimination of industrial dyes and artisanal dyeing simulated by methylene blue and iodine in the water. These are coconut shells (Coco nucifera) and teak wood chips (Tectona grandis). For the preparation of activated carbon based on coconut residues, the chemical activation was carried out by citric acid extracts of lemon juice (Citrus aurantiifolia) and then compared to that carried out with phosphoric acid and hydroxide of potassium. For the preparation of activated carbon from the teak residue, the activating agent used is potassium hydroxide. The results obtained show that activated carbon based on the coconut are microporous and mesoporous with an iodine number between 338.9 and 487.9 mg/g, a methylene blue number between 369.2 and 447.2 mg/g and a more pronounced post-treatment residual acidity for phosphoric acid than with lemon juice. The test conditions (the impregnation ratio, the duration, and the carbonization temperature) made it possible to prepare six activated carbons from the teak residue. The carbonization time does not have a significant effect on the adsorption efficiency although it does have a considerable effect on the carbonization efficiency. The adsorption kinetics of methylene blue on these materials is second order and the adsorption isotherm is more of the Langmuir type than that of the Freundlich model; this isotherm is characteristic of a wide distribution of microporosity and a well-developed mesoporosity. These activated carbons can therefore be used in the treatment of wastewater, in particular for the removal of industrial dyes and artisanal dyeing.