Simultaneous adsorption of lead (II) and 3,7-Bis(dimethylamino)-phenothiazin-5-ium chloride from aqueous solution by activated carbon prepared from plantain peels

Activated carbon has been prepared from plantain peels unripe, a biowaste from confectioneries for investigation of its adsorption efficiency in binary system of lead (II) and 3,7-Bis(dimethylamino)-phenothiazin-5-ium chloride as common water pollutants. The prepared carbons were characterized using nitrogen adsorption, FTIR spectroscopy, and XRD. Batch adsorption experiments were conducted to determine most probable conditions of adsorption maximum via varying adsorbent concentration, initial pollutants concentration, and pH of adsorption. Adsorption was found to be dependent on the factors studied. Favorable adsorption was recorded at initial concentration of 300 mg/dm³ after 30 min. Equilibrium and kinetic data were modeled using well-known isotherm and kinetic models. Results deviated largely from Langmuir monolayer, Freundlich multilayer and extended Langmuir isotherm models suggesting a mutual interaction of the adsorbates in solution which is shown with data obtained from competitive adsorption evaluation. Kinetics was fast and data fitted extensively to pseudo-second-order kinetic model with good correlation coefficient greater than 0.99. From the results of the analysis, mechanism of adsorption is proposed and adsorption using this adsorbent is feasible and could be developed as a low-cost alternative for the treatment of industrial effluent system of dye-metal matrix.