This chapter consists of concepts, and together with their definitions and reference to relevant scholarly literature, existing theory that will guide the proponent to come up with the utmost solution to the present problem. This chapter also shows the structure that can hold or support a theory of the design project.t
Review of Related Literature and Studies
History of Reverse Osmosis
Reverse Osmosis is a modification of the natural process known as osmosis. A French scientist first described the phenomenon of osmosis in 1748. This scientist noted that water spontaneously diffused through a pig bladder membrane into alcohol. Over 200 years later, researchers modified the process of osmosis and discovered and patented the process now known as reverse osmosis. The reverse osmosis allows the purification of contaminated water by removing dissolved and suspended matter. Reverse Osmosis has become a key process technology. Its use in industrial applications has had major advancements since the early 1960s.
Osmosis and Osmotic Pressure
Reverse Osmosis is a process that separates impurities from water by passing the water through a semi-permeable membrane. The semi-permeable membrane only allows very small atoms and group of atoms such as water molecules, small organics molecules, and gasses to go through it. Hydrated ions, or ions that have been dissolves and are therefore surrounded by water molecules, cannot pass through the membrane. In order to understand reverse osmosis, the osmosis process needs to be understood.
Osmosis and its Cause
When two solutions with different dissolved mineral concentrations are separated by a semipermeable membrane, water flows from the less concentrated to the more concentrated solution. The water level rises on the concentrated side of the apparatus.
The dilution of the solution with the higher concentration is caused by the process called osmosis. The simple definition of osmosis is the tendency of a fluid to pass through a somewhat porous membrane until the concentration on both sides is equal. Osmosis is the migration of water molecules across a membrane caused by the attraction of the dipole moment of water molecule to ions and polar molecule on the other side of a membrane.
Reverse Osmosis is a process that forces water molecules to flow against a net osmotic pressure. This is accomplished by applying enough pressure on the high concentration side of a semi-permeable membrane to reverse the net migration of water molecules.