Pecan shell based activated carbon (PSBAC) developed in this work had a high specific surface area (1500 m(2)/g) and pore volume (0.7 cm(3)/g). The maximum adsorption capacity of the PSBAC was found to be 41.66 mg/g at 55 mg/L iron(II), pH=3, 3 g/L adsorbent dose, at 90 min and at 30 degrees C. Iron(II) adsorption can be best described by the pseudo second order model. The adsorption system was thermodynamically favorable, endothermic and increase in entropy. The experimental data were fitted against common adsorption isotherms and yielded excellent fits in the following order: Temkin > Freundlich > Sips > Halsey Dubinin-Radushkevich > Langmuir > Harkins-Jura > Redlich-Peterson > Elovich. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.