A series of low-cost magnetic porous carbons (MPCs) were prepared via a pyrolyzation method using peanut shells as carbon resource and hydrochloric acid pickling wastewater as magnetic precursor. The physical-chemical properties were characterized by XRD, SEM, FTIR and BET technologies. The adsorption experiments of nitrobenzene (NB) on MPCs show that the adsorption performances were significantly affected by the carbonization temperature and MPC-973 presented the best adsorption capacity of 58.2 mg g(-1) at 288 K, which can be kept up to 82.2% even after six cycles. The obtained MPC can be recycled from aqueous solution under an external magnetic field reveals there is a good magnetism. The kinetics and isotherm results demonstrate that the adsorption mechanism of NB on MPC is heterogeneous adsorption, including surface area, porous structures, H-bond interaction, the pi-pi interaction and electrostatic interaction between the adsorbent MPC and NB molecules. (C) 2018 Elsevier B.V. All rights reserved.