Membrane technologies seawater desalination

Seawater or brackish water is used for process applications or as potable water when fresh water is scarce. Six techniques are used for desalination. Five are evaporation processes multiple-effect thermocompression mechanical vapor compression once-through multistage flash and multistage flash with brine recirculation. The sixth process, reverse osmosis, uses membrane technology for desalination. 

K.L. Tu, L.D. Nghiem, A.R. Chivas, Boron removal by reverse osmosis membranes in seawater desalination applications. Separation and Purification Technology 75 (2010) 87-101. 

Reverse osmosis membrane process, 27 637 Reverse osmosis membrane cleaning citric acid application, 6 647 Reverse-osmosis membranes, 75 811, 825 development of, 75 797 Reverse osmosis models, 27 638-639 Reverse osmosis permeators, 76 19 Reverse osmosis seawater desalination process, 26 85 Reverse osmosis systems blending in, 26 80-81 brackish and nanofiltration, 26 80-83 Reverse osmosis technology... 

The reverse-osmosis membrane process is considered universally as the most promising technology for brackish and seawater desalination [18]. Potential directions for reducing desalination costs may be deduced by analyzing the cost of the components. 

The most common uses of RO are for desalination of seawater and brackish water for potable and industrial applications. However, as demand for fresh water grows, RO is being pressed into service for wastewater and reuse applications. These will require extensive pretreatment, sometimes involving other membrane technologies such as micro- or ultrafiltration, to minimize fouling of the RO membranes (see Chapter 16). 

Hanemaaijer, J.H. Memstil—low cost membrane distillation technology for seawater desalination. Desalination, 168, 355, 2004. 

Matsuura, X., Progress in membrane science and technology for seawater desalination—a review. Desalination, 134, 47, 2001. 

Membrane contactors (MCs) represent another interesting frontier in the application of membrane technology in seawater desalination. Gas-liquid application for addition/extraction of selected gasses or operation like membrane crystallization has been recognized in some new experimental works, as important ways for improve efficiency and get some advantages for the overall desalination processes [5,6]. 

During the period of 1965 to 1972, the best data on flux and salt rejection for cellulose acetate membranes were exhibited by the composite membranes. However, these membranes never reached commercial viability efforts on them died out completely by 1975. Reasons for this appear to be threefold. First, composite cellulose acetate membranes were technically difficult to scale up. Second, the advent of noncellulosic composite membranes in 1972 (the NS-100 membrane) offered much more promise for high performance (salt rejection and water flux), especially for seawater desalination. Third, continual improvements in asymmetric cellulose acetate membrane casting technology (such as the development of swelling agents and of blend membranes) brought the performance of asymmetric membranes to full equality with composite cellulose acetate membranes. 

The present seawater desalination technology aims to increase the pure water recovery by a membrane module from the conventional 40% to 60%. Since the osmotic pressure of the retentate will increase from 4.5 to 7.0 MPa when... 

Gugliuzza A., Speranza V., Macedonio E, Drioli E. (2010), High-performance hydrophobic membranes for contactors and desalination technologies, Proc. of Advances in Science and Engineering for Brackish Water and Seawater Desalination (ECI), May 8-12, Cetraro, Italy, 122-124... 

Alessandra Criscuoli (membrane science and technology membrane distillation and membrane contactors integrated membrane processes water and wastewater treatment desalination of brackish water and seawater). Institute on Membrane Technology, ITM-CNR, Rende (CS)... 

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