Removal of Basic Fuchsine (BF) in aqueous solution by Adsorption Process onto ‘Prunus Cerasefera’ (LPC) - Kinetics, Isotherm modeling and Thermodynamic Study

Abstract

The Leaves Pruna Cerasefera (LPC) was developed for the adsorption of Basic Fuchsin (BF) from its aqueous solution. LPC with a specific surface area of 22 m2/g was characterized by the BET surface area, Fourier transform infrared spectroscopy (FTIR), and pH of zero point charge pHpzc (=6.80). The adsorptive properties of LPC with BF was conducted at variable stirring speed (100–1000 rpm), adsorbent dose (2–16 g/L), solution pH (2–10), initial BF concentrations (100–200 mg/L), contact time (0–60 min), and temperature (295–313 K) using batch mode operation to find the optimal conditions for a maximum adsorption. The adsorption mechanism of BF onto LPC was studied using the first pseudo order and second pseudo order kinetic models. The BF elimination was found to follow a pseudo-second order kinetic model with a determination coefficient ( R2) of 0.999. The experimental data were fitted to Langmuir, Freundlich, Temkin, and Elovich isotherms, and the equilibrium behavior explained by the Langmuir model provides the best correlation ( qmax = 158.73 mg/g, R2 = 0.999 at 25°C). The effect of adsorption at different temperatures have been studied for the determination of thermodynamic parameters, that is, the free energy (Δ G° = −5.4437 to −4.5879 kJ/mol), enthalpy (Δ H° = −19.469 kJ/mol), and entropy (Δ S° = −0.4554 kJ/mol K). The negative values of Δ G° and Δ H° values that the overall adsorption is spontaneous and exothermic in nature. Our work has a dual environmental aspect; on the one hand the valorization of a natural by-product namely LPC, and on the other hand, the elimination of BF from aqueous solutions. The present adsorbent may be considered as an alternative adsorbent for the better performance of the BF removal from its aqueous medium.