Adsorption process of reactive red 2 using a low-cost activated charcoal: isotherm, kinetics and thermodynamics studies

Activated charcoal with an appropriate functional group was synthesized by carbonizing method, from the stem of Albizia Lebbeck. The average 75-125 µm mesh was utilized to separate particles. The charcoal parameters of bulk density, surface area, moisture content, pH, and pHzpc have been measured, which are concurrent with literature-reported values. Chemical functionality was studied by FT-IR spectroscopy and particle size was confirmed by scanning electron microscopy. The dye, Reactive Red 2(Red2), adsorbs on the surface of activated charcoal through microscopic holes. General parameter variations, namely exposure time, adsorbent dosage, initial dye concentration, temperature, and pH of the dye solution, were used to find out the best condition for dye removal. Compare to the reported adsorbents that require acidic conditions (pH<5), the prepared charcoal has been capable of absorbing Reactive Red 2 at an ambient pH of 5.5. The equilibrium adsorption data were found to match with the Langmuir and Freundlich isotherms, and thermodynamic tests indicated the endothermic adsorption process. Furthermore, it has been proven by Lagergren and models, that the monolayer coverage and first-order kinetics of adsorption indicate the scalability of the adsorptive process for large-scale dye removal from waste-water streams