The present study provides an electrocoagulation (EC) process for the removal of p-benzoquinone (BQ) from aqueous solution using aluminium as anode and stainless steel as cathode materials. Experiments carried out to investigate the effects of solution pH and conductivity, current density, time, BQ concentration on the removal efficiency of the process and the adsorption capacity of aluminium hydroxide electrocoagulant flocs. The results show that pH 7.5 seems to be optimum for high removal of BQ near 90% at typical operating conditions such as 20 A/m(2) current density and 20 min operating time. The competing reduction of BQ to hydroquinone (HQ) accompanying the H+ reduction at the cathode and low removal extent of HQ by electrocoagulant flocs decreases the performance of the EC process. (C) 2009 Elsevier B.V. All rights reserved.