Bioremoval of Safranin O dye by the identified lichen species called Evernia prunastri biomass; biosorption optimization, isotherms, kinetics, and thermodynamics

Evernia prunastri (lichen), a novel, eco-friendly, cost-effective, wide availability, safe, renewable and easy collection biosorbent, has been utilized for the removal of Safranin O (SO) dye from an aqueous solution. The biosorption behavior of SO onto the lichen biomass was investigated concerning parameters such as initial SO concentration (10-2000 mg L-1), solution pH (2.0-12.0), lichen biomass dosage (1-20 g L-1), contact time (2-1440 min), temperature (5 degrees C, 25 degrees C, and 40 degrees C), and recovery were investigated. The zeta potential analyses showed that electrostatic attraction existed during the biosorption process between the SO and lichen biomass. The maximum SO biosorption capacity of the lichen biomass was 0.257 mol kg(-1) at pH 6.0 and 25 degrees C. The biosorption energy for SO onto the lichen biomass was found to be E(DR:)8.9 kJ mol(-1) reveals the biosorption proceeds chemically. The biosorption process follows the pseudo-second order and intra particle diffusion rate kinetics. Thermodynamic studies showed that SO biosorption, by this the lichen biomass is possible, spontaneous, and endothermic.

Automated summary

Evernia prunastri (lichen) has been used as a biosorbent for the removal of Safranin O (SO) dye from aqueous solution, showing good adsorption capacity and following mainly chemical adsorption process with endothermic properties. Thermodynamic studies suggest that the biosorption of SO by the lichen biomass is possible, spontaneous, and endothermic.