The Lantana camara L. stem biomass as an inexpensive and efficient biosorbent for the adsorptive removal of malachite green from aquatic environments: kinetics, equilibrium and thermodynamic studies

Abstract

Plant biomass is one of the available and economic biomaterials used to remove environmental pollutants. The presence of colored compounds in aqueous solutions is one of the problems that can be solved by biological methods. Herein, the efficiency of available and inexpensive biomass obtained from Lantana camara L. stem for cationic dye uptake has been evaluated. The effect of operational factors, including dosage of L. camara L. stem biomass (LSB), pH of the solution, initial concentration of malachite green (MG), and residence time on the optimal conditions of analyte uptake was studied. The experimental data of adsorption studies fit with P-S-O kinetic ($R^2=0.999$) and L.I.M ($R^2=0.998$), indicating MG dye adsorption onto LSB occurred in monolayers due to its chemical affinity. The maximum uptake capacity of LSB for the removal of MG dye was 100 mg g^-1. Thermodynamic parameters, including $\Delta G°$ (from -2.13 to -2.469 $\text{kJ mo}{l}^{-1}$), $\Delta H°$ (+2.916 $\text{kJ mo}{l}^{-1}$), and $\Delta S°$ (+16.934 $\text{J mo}{l}^{-1}{K}^{-1}$) suggested that the adsorption process was endothermic and spontaneous. The results revealed that LSB considerably has potential for adsorptive removal of cationic dyes such as, MG from aquatic environments.

Keywords: Biomass powder; Lantana camara L. stem; biosorption mechanism; malachite green.