Biosorption studies of mushrooms for two typical dyes

Abstract

This study investigated the adsorption behaviour of two cationic dyes, methylene blue (MB) and malachite green (MG) onto Pleurotus ostreatus, Armillaria tabescens, and Morchella conica mushrooms. The effects of contact time, initial dye concentration, and solution pH (3-11) were also determined. The adsorption on all mushrooms attained equilibrium within 120 min for both MB and MG. To evaluate the experimental kinetics data, the pseudo-first-order, pseudo-second-order, and intraparticle diffusion kinetics equations were utilised. The pseudo-first-order kinetic model demonstrated a good fit with all adsorption kinetics. The Langmuir and Freundlich isotherm models were used to analyse the mechanism of the adsorption isotherm. The adsorption equilibrium isotherm was in a good agreement with the Freundlich model. Thermodynamic parameters such as ΔH enthalpy variation, ΔS entropy variation, and ΔG free Gibbs energy variation were calculated at 303-323 K. The results suggested that the Pleurotus ostreatus mushroom was the most suitable adsorbent for both cationic dyes’ removal.