In this study, high density polyethylene (HDPE) membranes embedded with ZnO nanoparticles were fabricated via thermally induced phase separation (TIPS) method. A series of tests including FESEM, XRD, TGA, AFM, contact angle measurement, pure water flux, porosity and mean pore radius were performed for characterization of membranes. FESEM images showed that the membranes had leafy structure indicating solid-liquid phase separation mechanism. The results of XRD and TGA analysis confirmed the presence of ZnO nanoparticles in the polymer matrix. AFM images showed that the surface roughness of ZnO embedded membranes were higher than that of neat HDPE membrane. Pure water flux as well as surface hydrophilicity of membranes improved as the ZnO content increased. In addition, the fouling behavior of membranes was investigated by filtration of collagen protein solution. The governing fouling mechanisms of membranes were also investigated using classic models as well as combined fouling models. The results showed that for all membranes the best fit of the data occurred with the cake filtration-complete blockage model (CFCBM). Moreover, the deviation between experimental data and CFCBM prediction decreased by increasing the content of ZnO. (C) 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.