Copper biosorption by pine cone shell and thermal decomposition study of the exhausted biosorbent

Pine cone shell (PCS), a vegetable solid waste has been used as effective and efficient biosorbent for the removal of Cu(II) from aqueous solutions. The biosorbent was characterized by elemental analysis, potentiometric titrations, surface area and pore size distribution and FTIR analyses. Batch adsorption experiments were carried out as a function of solution pH, particle size, biosorbent dosage, contact time, and initial metal ion concentration. Then, equilibrium isotherms and kinetic data parameters were evaluated. Equilibrium data agreed well with Langmuir isotherm model. The biosorption capacities of PCS for Cu(II) were determined at 25 °C with the Langmuir model as 6.81 mg/g. The kinetics data fitted well into the pseudo-second-order model with correlation coefficient greater than 0.99. Also, dynamic biosorption studies were carried out using a packed-bed column and the main column parameters were determined. Pine cone shell was shown to be a promising biosorbent for Cu(II) removal from aqueous solutions. Finally, the pyrolysis characteristics of native PCS and Cu-loaded PCS were investigated by thermogravimetric analysis (TGA) in order to study the possible recycling of PCS after its use as biosorbent of copper.