In this paper, we have reported the preparation of low cost gamma-Al2O3 membrane on a macroporous clay support by dip-coating method. For the synthesis of gamma-Al2O3 top layer on the support, a stable boehmite sol is prepared using aluminium chloride salt as a starting material by sol-gel route. The structural properties of the composite membrane as well as gamma-Al2O3 Powder is carried out using scanning electron microscopy (SEM), X-ray diffraction (XRD), nitrogen adsorption-desorption isotherm data, Fourier transform infrared analysis (FTIR) and dynamic light scattering (DLS) analysis. The mean particle size of the boehmite sol used for coating is found to be 30.9 nm. The pore size distribution of the gamma-Al2O3-clay composite membrane is found to be in the range of 5.4-13.6 nm. Separation performance of the membrane in terms of flux and rejection of single salts solution such as MgCl2 and AlCl3 as a function of pH, salt concentration and applied pressure is also studied. The rejection and flux behavior are found to be strongly dependent on electrostatic interaction between the charged molecules and gamma-Al2O3-clay composite membrane. The intrinsic rejection has been determined by calculating the concentration at membrane surface (C.) using Speigler-Kedem model. It is found that the observed rejection shows anomalous trend with increase in applied pressure and the intrinsic rejection increases with increase in applied pressure, a trend typical of the separation of electrolyte through charged membranes. At acidic pH, both the salt solution shows higher rejection. With increase in the salt concentration, observed rejection of salt decreases due to the enhanced concentration polarization. The maximum rejection of MgCl2 and AlCl3 is found to be 72% and 88%, respectively for salt concentration of 3000 ppm. (C) 2009 Elsevier B.V. All rights reserved.