Removal of nonylphenol (NP) from aqueous solution has attracted widely attention due to its aquatic toxicity and potential to disrupt the endocrine system. In an effort to develop the effective and environment-friendly treatment method for NP, adsorption of 4-n-nonylphenol (4-NP) on multi-walled carbon nano-tubes (MWCNTs) under electrochemical assistance was studied. The adsorption kinetics and isotherms were investigated at different polarization potentials and compared with those of open circuit (DC) and powder MWCNTs adsorption. The adsorption kinetics was simulated by the model including pseudo-first-order model, pseudo-second-order model and intraparticle diffusion model. The isotherm was simulated with Langmuir model and Freudlich model, respectively. Experimental results indicated that 4-NP is able to be efficiently removed at a potential of -0.6 V. Comparing with that of powder MWCNTs adsorption, the initial adsorption rate nu(0) at -0.6 V increased 7.9-fold according to pseudo-second-order model and the maximum adsorption capacity q(m), improved 1.7-fold according to Langmuir model. The improved adsorption effect at negative potential was ascribed to enhanced pi-pi electron-donor-acceptor (EDA) interaction between 4-NP and MWCNTs under electrochemical assistance. (C) 2013 Elsevier Inc. All rights reserved.