Equilibrium, kinetic and thermodynamic studies for the removal of Reactive Red dye 120 using Hydrilla verticillata biomass: A batch and column study

In this study, Hydrilla verticillata (H. verticillata) biomass is utilized to separate Reactive Red 120 (RR120) dye from simulated wastewater. Its impact on pH, initial dye concentration, biosorbent dosage and temperature was studied. From the examination of the isotherms in equilibrium sorption, it is found that Freundlich's isotherm correlation coefficient is a perfect fit. The calculated parameters of thermodynamics conclude that the sorption of RR120 molecules occurs by an endothermic process. Adsorption studies using kinetic models indicate that pseudo-second-order equation fits closely. Maximized removal of dye occurs at favorable conditions of 323 K temperature, 105 mg L-1 initial concentration of dye, 0.2 g L-1 sorbent dose and 2 pH which are established by the measure of coefficient of determination (R-2 = 0.99). Since the chosen biosorbent was found to be effective in batch studies, column experiments were conducted and the optimal conditions of bed height, flow rate and concentration were found to be 3 cm, 5 mL min(-1) and 30 mg L-1. Experimental data indicated a good fit on using the Thomas model. (C) 2021 The Authors. Published by Elsevier B.V.