A novel route for preparation of chemically activated carbon from pistachio wood for highly efficient Pb(II) sorption.

Abstract Pistachio wood-derived activated carbon prepared by a two-stage process (PWAC-2), conducting two consecutive chemical activation processes with NH 4 NO 3 and NaOH, respectively. The results showed that explosive characteristic of NH 4 NO 3 can primarily be employed to produce a char, with a large surface area and a highly-ordered pore structure, which can be subjected to a second activation process with NaOH to prepare a more suitable activated carbon, with a highly porous structure and useful functional groups, for removal of lead ions from aqueous media. An L 25 Taguchi experimental design was used by varying impregnation ratio, activation time and temperature in both pre- and post-activation stages, and the results showed that, in both stages, a small activating agent/precursor and a proportional low activation time suffice for preparation of an advantageous activated carbon for Pb(II) adsorption. A comprehensive study was performed on the equilibrium, kinetic and thermodynamic aspects of Pb(II) adsorption by the new activated carbon. The results exhibited that, having had a high lead adsorption capacity (190.2 mg g−1), a high adsorption rapidness, and thermodynamic favorability, PWAC-2 is a beneficial alternative for utilization in full-scale plants of lead removal from waters and wastewaters. Highlights • Suitable activated carbon for Pb(II) removal was produced by two-stage activation process. • NH 4 NO 3 and NaOH were, respectively, used as pre- and pro-activation agents. • A small activating agent/precursor and a low activation time were enough for activation. • Explosive characteristic of NH 4 NO 3 resulted in a char with a highly-ordered pore structure. • NaOH as pro-activating agent raised the activated carbon efficiency for Pb(II) sorption. [ABSTRACT FROM AUTHOR]