Crosslinked aromatic polyamide membrane membranes

Nakase Y. Irradiation effects on properties of reverse osmosis membrane based on crosslinked aromatic polyamide. J Nucl Sci Technol 1994 31 1214 1221. 

The Permutit Liberator 1 reverse osmosis unit contains two spiral wound modules of 0.96 m each with Filmtec BW30 membranes, a crosslinked aromatic polyamide. These were selected based on low adsorption and high rejection characteristics. 

M. Kurihara, Y Himeshima, and T. Uemura, Crosslinked aromatic polyamide ultra-thin composite membrane from 1,3,5-Triaminobenzene, Proceedings of die 1990 InternatUmal Congress on Membranes and Membrane Processes, 1034 (1990). 

Kurihara, M., Uemura, T., Himeshima, Y., Ueno, K., and Bairinji, Y. (1994b). Development of crosslinked aromatic polyamide composite reverse osmosis membrane. Nippon Kagaku Kaishi 1994(2), 97-107. 

The predominant RO membranes used in water applications include cellulose polymers, thin film oomposites (TFCs) consisting of aromatic polyamides, and crosslinked polyetherurea. Cellulosic membranes are formed by immersion casting of 30 to 40 percent polymer lacquers on a web immersed in water. These lacquers include cellulose acetate, triacetate, and acetate-butyrate. TFCs are formed by interfacial polymerization that involves coating a microporous membrane substrate with an aqueous prepolymer solution and immersing in a water-immiscible solvent containing a reactant [Petersen, J. Memhr. Sol., 83, 81 (1993)]. The Dow FilmTec FT-30 membrane developed by Cadotte uses 1-3 diaminobenzene prepolymer crosslinked with 1-3 and 1-4 benzenedicarboxylic acid chlorides. These membranes have NaCl retention and water permeability claims. 

As Figure 5.12 shows, Toray s PEC-1000 crosslinked furfuryl alcohol membrane has by far the best sodium chloride rejection combined with good fluxes. This explains the sustained interest in this membrane despite its extreme sensitivity to dissolved chlorine and oxygen in the feed water. Hollow fine fiber membranes made from cellulose triacetate by Toyobo or aromatic polyamides by Permasep (Du Pont) are also comfortably in the one-stage seawater desalination performance range, but the water fluxes of these membranes are low. However, because large-surface-area, hollow fine fiber reverse osmosis modules can be... 

In reverse osmosis membranes, we tried to introduce high amide linkage into polyamide membrane to realize better salt rejection and better water flux. Consequently, crosslinked fully aromatic polyamide membrane from 1,3,5-Triaminobenzene has found to have excellent separation performance and durability. Moreover, based on "UTC-70", fully aromatic polyamide membrane from 1,3,5-Triaminobenzene commercialized by Toray, various types of membrane have developed to satisfy different requirements in wide ranges of application. In such membranes, controlling membrane performance is accomplished through composition of membrane materials, control of polycondensation reaction, physical treatment and chemical treatment, which are closely related to chemical and physical structures of membranes. 

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