Effective biosorption of Allura red dye from aqueous solutions by the dried-lichen (Pseudoevernia furfuracea) biomass

Abstract

Allura red (AR), which is known as the monoazo class of synthetic food colourant(E129) has been widely used in food industries. Due to the potential toxicity of azo dyes and pathogenicity, the removal of AR from industrial wastewaters is very important environmen-tally. So, this article aims to investigate the biosorption process of AR by lichen (Pseudoevernia furfuracea) from aqueous solutions. Batch biosorption conditions of AR food dye onto lichen biosorbent as initial AR concentration, solution pH, contact time, temperature and recovery were investigated. From the results, it has been observed that the highest removal efficiency is approximately 87% at a contact time of 5 hours, initial AR food dye concentration of 1000 mgL−1 and agitation speed of 150 rpm at natural pH 8.0. The maximum ARbiosorption capacity from the Langmuir model was found as 0.280 mol kg−1 at 25°C. Biosorption kinetics were analysed by using intra-particle diffusion and pseudo-second- order models. Biosorption thermodynamics has shown that ARbiosorption onto lichen biosorbent is endothermic, possible and spontaneous. The lichen (Pseudoevernia furfuracea) can become an alternative biosorbent for the removal of AR from the environment and wastewater.