Valorization of Romanian silver fir tree bark (Abies alba Mill.) wastes as low-cost sorbent of Cu(II) ions from polluted waters

Abstract

Considering recycling as the first option in the hierarchy of sustainable waste management, and also the demand for efficient processes for wastewater treatment with reduced costs, the potential applicability of Romanian Abies alba bark, the main waste from the industrial processing of the wood of mature silver fir trees, as sorbent for Cu(II) has been studied in batch conditions. It was observed that the extent of Cu(II) sorption is strongly dependent on initial solution pH, sorbent dose, initial Cu(II) ion concentration, temperature and contact time. Equilibrium data fitted very well with both Langmuir and Freundlich isotherm models. The Langmuir maximum sorption capacity of Cu(II) ions on Abies alba bark waste was found to be 7.80 mg/g at 293 K. Kinetic studies showed a high affinity of the sorption experimental data to the pseudo-second order model. Gibbs free energy was spontaneous for all interactions and the sorption process exhibited endothermic enthalpy value. The waste of Abies alba bark was successfully used for the sorption removal of Cu(II) ions from industrial electroplating wastewaters.