Biosorption of copper (II) from aqueous solutions by raw and chemically modified Thymus pannonicus in batch and fixed-bed systems

In this study, the Cu(II) biosorption potential of the raw (RTP) and modified Thymus pannonicus (MTP) leaves was investigated in batch and continuous systems. FTIR, SEM, SEM-EDX and Zeta potential analyses were used for the characterisation of biomass. In the batch system, pH, amount of biosorbent, initial heavy metal concentration, contact time and temperature parameters were studied. According to the optimum pH and biosorbent amount determined in the batch system, the effect of the flow rate and column bed height on the biosorption was investigated by MTP in the continuous mode. Langmuir and Freundlich isotherm models were used to explain the biosorption mechanism, and it was seen that both biomasses conformed to the Langmuir isotherm. Pseudo-first-order and pseudo-second-order kinetic models were used in kinetic studies, and both RTP and MTP followed the pseudo-second-order kinetic model. While the equilibrium was established in 20 min in the removal of Cu(II) with RTP, this value increased to 30 min with MTP. The maximum monolayer biosorption capacity was determined as 46.21 mg/g for RTP and 82.70 mg/g for MTP. Column studies showed that the MTP was successful in removing Cu(II) from the solution in the continuous system.