Recent Advances in RO Membrane Technology

Since the 1970 s, the membrane industry has focused on developing membranes that exhibit ever greater rejection of solutes while at 

Year Pressure (psi) Relative Flux Rejection (%) Membrane Material 

Since the late 1970 s, researchers in the US, Japan, Korea, and other locations have been making an effort to develop chlorine-tolerant RO membranes that exhibit high flux and high rejection. Most work, such as that by Riley and Ridgway et.al., focuses on modifications in the preparation of polyamide composite membranes (see Chapter 4.2.2). Other work by Freeman (University of Texas at Austin) and others involves the development of chlorine-tolerant membrane materials other than polyamide. To date, no chlorine-resistant polyamide composite membranes are commercially available for large-scale application. 

Along similar lines, other researchers have been looking into nanocomposite membranes. Researchers at the University of Colorado at Boulder have been developing lyotropic liquid crystals (LLCs) to form what they call nanostructured polymer membranes. The LLCs can from liquid crystalline phases with regular geometries 

In addition to the progress shown in Table 1.1, some membranes now exhibit up to 99.85% rejection (a drop of 50% in salt passage over membranes exhibiting 99.7% rejection). Other advancements in membrane technology include low pressure RO membranes that allow for operation 

Along similar lines, other researchers have been looking into nanocomposite membranes. Researchers at the University of Colorado at Boulder have been developing lyotropic liquid crystals (LLCs) to form what they call nanostructured polymer membranes. The LLCs can form liquid crystalline phases with regular geometries which act as conduits for water transport while rejection ions based on size exclusion. In bench-scale tests, nanostructuered polymer membranes exhibited a rejections of 95% and 99.3% of sodium chloride and calcium chloride, respectively. These membranes also exhibited greater resistance to chlorine degradation than 

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It also includes new chapters in the field of membrane science and technology covering recent advances in RO and UF, ionic liquids, nanotechnology, roles of membrane in power generation, updates on fuel cells, new membrane extraction configuration, and other important topics. 

Focusing on the recent advances and updates, this section addresses new development in chemical and pharmaceutical industries and in the conservation of natural resources. Included in this edition are newer practices and technologies and their applications or trends for future applications with relevant references that have appeared in the literature since the first edition was published. Several new chapters on emerging areas such as membrane separation in petrochemical oil refinery, chitosan as new material for membrane preparation, new membrane material for ultrafiltration (UF) and nanofiltration (NF), and potential application of reverse osmosis (RO) in chemical industry have been added in the second edition. 

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