In this paper, the newly prepared ZnO/HZSM-5 nanocomposites were suggested as the promising alternative materials for conventional means of waste water treatment. The combination effect of adsorption-photodegradation for the removal of 4-nitrophenol (4-NPh), as a biorefractory pollutant, occurred successfully when 7 wt.% of ZnO nanoparticles were incorporated in HZSM-5 zeolite. It was found that both the hydrophobicity and size-selectivity of HZSM-5 toward 4-NPh enhanced the adsorption process. The photodegradation of 4-NPh solutions was performed under UV irradiation and the influence of various parameters such as ZnO loading amount, pH dependence and initial concentration of 4-NPh were investigated. The results indicated that during the fixed reaction time (90 min) about 91% total organic carbon of solution, containing 4-NPh (20 mgl(-1)) was removed at pH = 5. Batch kinetic studies were conducted to evaluate the adsorption-photodegradation process. The pseudo-second-order fit well over the range of reaction time. It can be suggested that encapsulating ZnO clusters in the zeolites is a proper way to inhibit the agglomeration of ZnO nanoparticles and also to retard the recombination of photogenerated electron-hole in photocatalytic activity. (C) 2011 Elsevier B.V. All rights reserved.