TAILIEUCHUNG - A Brief Review of Reverse Osmosis Membrane Technology

The production process is based mainly on the use of natural fibers-primarily of wood but with significant reliance on non- wood fibers in the developing world. Apart from this a large number of other inputs also affect the production of paper & its products. The predominantly contributing factors are; chemicals, water, fillers and energy which play a significant role in quality and cost effective production of paper products. This reliance on harvested products makes the sector an. | A Brief Review of Reverse Osmosis Membrane Technology Michael E. Williams . The concepts of osmosis and reverse osmosis have been known for many years. In fact studies on osmosis were carried out as early as 1748 by the French scientist Nollet and many researchers investigated these phenomena over the next two centuries Reid 1966 Mason 1991 . However the use of reverse osmosis RO as a feasible separation process is a relatively young technology. In fact only in the late 1950 s did the work of Reid show that cellulose acetate RO membranes were capable of separating salt from water even though the water fluxes obtained were too small to be practical Reid and Breton 1959 Ferguson 1980 Lonsdale 1982 Applegate 1984 . Then in the early 1960 s Loeb and Sourirajan developed a method for making asymmetric cellulose acetate membranes with relatively high water fluxes and separations thus making RO separations both possible and practical Loeb and Sourirajan 1962 Loeb 1981 Sourirajan and Matsuura 1985 . Since then the development of new-generation membranes such as the thin-film composite membrane that can tolerate wide pH ranges higher temperatures and harsh chemical environments and that have highly improved water flux and solute separation characteristics has resulted in many RO applications. In addition to the traditional seawater and brackish water desalination processes RO membranes have found uses in wastewater treatment production of ultrapure water water softening and food processing as well as many others Bhattacharyya et al. 1992 . An estimate indicated that sales of RO membrane products had grown to 118 million yearly in 1990 with great potential for continued growth Riley 1990 . The driving force for the development and use of RO membranes is the advantages that these have over traditional separation processes such as distillation extraction ion exchange and adsorption. Reverse osmosis is a pressure-driven process so no energy-intensive phase changes or .

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