B. sempervirens tree leaves were successfully used to remove Cu(II), Zn(II) and Ni(II) from the aqueous solution. In order to improve the uptake capacity of sorbent, it was modified with various chemical agents, such as NaOH, HNO 3 , NaCl, H 3 PO 4 and SDS. Among the modifiers, NaOH was the best. The Simplex lattice mixture design was successfully employed for optimization of the biosorption process. The effective factors on the biosorption process, such as pH, s (amount of biosorbent) and C (initial concentrations of metal ion), were considered via the use of a crossed mixture process design. The biosorbent was characterized by SEM micrographs, a pH of point of zero charge (pH pzc ), a BET analysis of surface area, XPS, energy dispersive X-ray microanalysis (EDX) for elemental analysis/composition. Eventually, FT-IR analysis and different kinetic models and equilibrium modeling studies for the current biosorption process were evaluated.
