International Journal of Advanced Research in Chemical Science (IJARCS) Volume 5, Issue 2, 2018, PP 20-26 ISSN No. (Online) 2349-0403 DOI: http://dx.doi.org/10.20431/2349-0403.0502005 www.arcjournals.org International Journal of Advanced Research in Chemical Science (IJARCS) Page | 20 Reverse Osmosis Technology, its Applications and Nano-Enabled Membrane Ahamefula A. Ahuchaogu 1 , Okonkwo Joseph Chukwu 2 , A. I. Obike 1 , Chitua E. Igara 3 , Innocent Chidi Nnorom 1 , John Bull Onyekachi Echeme 2 1 Department of pure and industrial chemistry, Abia State University, Uturu Nigeria. 2 Department of chemistry, Michael Okpara University of Agriculture, Umudike, Umuahia, Abia State Nigeria, 3 Department of science Laboratory Technology, Akanu Ibiam Federal Polytechnic, Uwana Ebonyi State, Nigeria 1. INTRODUCTION Nowadays, desalination has become a very affordable solution to cope with fresh water shortage typically in tropical as well as off-shore areas. The desalination core process is based on Reverse Osmosis membrane technology. Reverse Osmosis (RO) is a method of obtaining pure water from water containing a salt, as in desalination [1]. It is a water purification technology that uses a semi permeable membrane to remove ions, molecules and larger particles from drinking water. In reverse osmosis, an applied pressure is used to overcome osmotic pressure, a colligative property that is driven by chemical potential differences of the solvent, a thermodynamic parameter. Reverse osmosis can remove many types of dissolved and suspended species from water, including bacteria and is used in both industrial processes and the production of potable water. The result is that the solute is retained on the pressurized side of the membrane and the pure solvent is allowed to pass to the other side. The membrane is expected to be selective not to allow large molecules or ions through the pores (holes), but should allow smaller components of the solution (such as solvent molecules) to pass freely [2]. In the normal osmosis process, the solvent naturally moves from the region of low solute concentration (high water potential), through a membrane, to a region of high solute concentration (low water potential). The driving force for the movement of the solvent is the reduction in the free energy of the system when the difference in solvent concentration on either side of a membrane is reduced, generating osmotic pressure due to the solvent moving into the more concentrated solution. Applying an external pressure to reverse the natural flow of pure solvent, thus, is reverse osmosis. Reverse osmosis also involves diffusion, making the process dependent on pressure, flow rate and other conditions [3]. It is most commonly known for its use in drinking water purification from sea water, removing the salt and other effluent materials from the water molecules. Abstract: Reverse Osmosis (RO) is the finest of all membrane filtration system, it is a membrane based technology to purify water by separating the dissolved solids from feed stream resulting in permeate and reject stream for a wide range of applications in domestic as well as industrial applications. The objective of this paper is to review the concept of reverse osmosis and the current developments in the RO membrane materials which are the key determinants in the process. This review paper also presents the concept of membrane cleaning, emergence of nanomembranes and mixed matrix membrane materials as well as the various applications of RO systems. Keywords: Membrane materials, Osmosis, Reverse Osmosis (RO) Desalination, Nano-materials. *Corresponding Author: Ahamefula A. Ahuchaogu, Department of pure and industrial chemistry, Abia State University, Uturu Nigeria.