One of the suitable methods for removing heavy metals from waste water is using surface adsorption process. In this article, the preparation of polyaniline and its composites as adsorbents are discussed and the capability of separating chromium from industrial waste water is studied. The results were compared with anthracite and cation exchangers such as purolite-302 and amberjet. The observations indicated that the purolite and amberjet have the most chromium removal percentage. Also the role of polyaniline and its composite as adsorbents were studied. The results show that the percentage of chromium removal has increased in polyaniline/poly(vinyl alcohol) composite. Furthermore, the adsorption percentage is related to the surface morphology, type of adsorbents, and their weight ratios. (c) 2007 Wiley Periodicals, Inc.