Influence of Process Variables and Kinetic Modelling on Mercury Removal Using Paecilomyces variotii Biomass—Effect of Process Parameters and Kinetics

Abstract

In this present work, a novel fungal biosorbent was synthesized using Paecilomyces variotii species and employed for the removal of mercury under batch conditions. The effect of process parameters such as pH, sorbent dose, initial mercury concentration and agitation speed on metal removal efficiency was investigated. The metal uptake was found to increase in the pH range 2.0 – 5.0 and the maximum uptake obtained was 26.0 mg/g at an optimal pH of 5.0. The biosorbent achieved 86% metal removal efficiency when the mercury concentration was 100 mg/L. The effect of shaking speed was studied in the range of 100-400 rpm and the optimal speed was determined as 300 rpm. The sorption process was identified as exothermic in nature. Pseudo-first order and pseudo-second order model were tested with the kinetic data. The pseudo-second order model represented the kinetic experiments very well with higher values of R² (>0.95). The pseudo-second rate constant (k₂), was evaluated as 2.090 × 10⁻³ g mg⁻¹ min⁻¹ at an initial mercury concentrations of 100 mg/L. Thermodynamic studies revealed the activation energy for this process as 58.25 kJ/mol.