In this study excess adsorption of fluid on the surface of spherical nanoparticles have been studied and the impact of fluid structure consists of homogeneous and heterogeneous structure on the amount of adsorption is studied.It should be noted that the study of these systems MFMT density functional theory methods were used. Our studies show that increasing the size of hard spherical nanoparticles, hard spherical homogeneous fluid adsorption and homogenous Lennard-Jones fluid on its surface has been increased. By increasing the density of the bulk fluid based on entropy of nanoparticle uptake in the hardware increases. It was also observed that adsorption hard sphere fluid is more than Lennard-Jones fluid because of the interactions between the molecules in the fluid Lennard-Jones. Adsorption of heterogeneous fluid showed that excess adsorption have highly oscillatory behavior. So that its maximum and minimum values of integer and half integer values H*can be seen. Studies suggest that is reducing the amount of fluid adsorption by increasing the size of the adsorbent nanoparticle. Also, by increasing the density of the bulk fluid decreases amount of adsorption. Our studies showed that on surface of the adsorbent nanoparticle, Lennard-Jones fluid is adsorbing more than hard sphere fluid. After excess adsorption study, we investigated the effect of curvature in the structure of dense confined fluids in a small nanopore at H*= 2. The equilibrium density distribution function of these systems strongly convex or concave curvature and the curvature of the walls is subject to change. But our studies showed that around H*=2 in bispherical pore density along two walls is the same as a slit nanopore. The curvature of the walls of small nanoporous is not role in determining the structure of confined fluid. It should be noted that this fluid behavior only at high densities such as 0.9, was observed.To explain this phenomeno we used the concept of packing fraction, that is given by n3.According curves n3 with increasing the size of nanopores of H = 1.8 and H = 1.9 to H = 2 structure of fluid from 3 molecular layers with maximum entropy changes to 2 molecular layers with high order . thermodynamic potential curves and the failure of its first derivative curve and discontinuity in the second derivative curve represents a second-order phase transition In physical chemistry, which will be a structural phase transition.
