Ficus religiosa bark an efficient adsorbent for Alizarin Red S dye: Equilibrium and kinetic analysis

The discharge of unsafe color dyes into the effluents of various industries can harm the environment and human health and therefore needs remediation. The current research assesses the environmental friendly decontamination of the Alizarin Red S (ARS) dye from industrial aqueous effluents by powder bark of a low-cost and indigenous plant, Ficus religiosa, as a biosorbent. The biosorbent was processed, powdered, and then characterized via SEM and FTIR spectroscopy before and after exposure to ARS. For maximum dye-decontamination of industrial effluents, adsorption parameters including dosage of the biosorbent, contact time between the dye and the biosorbent, shaking time and temperature of the adsorption process were optimized. SEM images confirmed the presence of high surface area active binding sites, and FTIR analysis shows that the adsorption of ARS on the adsorbent is due to groups like ‒OH, –NH, –CH, C=O and C=C. The kinetics study of the adsorption follows pseudo-second order kinetic model. Best fit isotherm to the equilibrium data was obtained for Langmuir and Freundlich models. The decontamination ARS from aqueous phase by the adsorption process could be an inexpensive and viable way of protecting humans from carcinogenicity, DNA mutagenicity, jaundices, allergies and skin irritations.