Biosorption of nickel ions Ni(2+) by natural and modified Pinus caribaea Morelet sawdust

The potential of Pinus caribaea Morelet sawdust for the removal of nickel ions (Ni(2+)) and other metallic trace ions (Co(2+), Cr(3+), Mn(2+)) from aqueous solutions was investigated under batch conditions. Several parameters such as size of particles, contact time, pH, initial metal and biomass concentrations, desorption conditions and reusability were evaluated on natural biomass. Biosorption was fast, effective (73%) and biomaterial can be reused after five cycles. To enhance the removal capacity of nickel, pine sawdust was modified by acidic and oxidative treatments. Cellulosic residues from sawdust sequential extraction showed great biosorption capacity (96%). In the presence of a metal mixture, oxidized sawdust had better selectivity for Cr(3+) ions than for Ni(2+). Pinus caribaea biomass could be an environmental, inexpensive and renewable material for the depollution of water laden with metallic trace elements.