Nanofiltration FILMTEC

Fig. 1. Water flux and NaCl rejection of several membrane types (10), where (D) represents seawater membranes, which operate at 5.5 MPa and 25°C ( ), brackish water membranes, which operate at 1500 mg/L NaCl feed, 1.5 MPa, and 25°C and (SSI) nanofiltration membranes, which operate at 500 mg/L NaCl feed, 0.74 MPa, and 25°C. A represents cellulose acetate—cellulose triacetate B, linear aromatic polyamide C, cross-linked polyether D, cross-linked fully aromatic polyamide E, other thin-film composite membranes F, asymmetric membranes G, BW-30 (FilmTec) H, SU-700 (Toray) I, A-15 (Du Pont) J, NTR-739HF (Nitto-Denko) K, NTR-729HF (Nitto-Denko) L, NTR-7250 (Nitto-Denko) M, NF40 (FilmTec) N, NF40HF (FilmTec) O, UTC-40HF (Toray) P, NF70 (FilmTec) Q, UTC-60 (Toray) R, UTC-20HF (Toray) and S, NF50 (FilmTec). To convert MPa to psi,...

Table 2.6 Rejection of microsolutes by nanofiltration membranes (FilmTec data) [73], Reprinted from Desalination, 70,...

As already mentioned, TFC membranes are fabricated by in situ polymerization. This method, developed by Cadotte and coworkers of Filmtec in the 1970s, is currently most widely used to prepare high-performance RO and nanofiltration (NF) membranes [8]. A thin selective layer is deposited on top of a porous substrate membrane by interfacial in situ polycondensation. There are a number of modifications of this method primarily based on the choice of the monomers [13]. However, for the matter of simplicity, the polycondensation procedure is described by a pair of diamine and diacid chloride monomers. 

RO experiments with low pressure and high pressure membranes were performed by using four types of commercial membranes supplied by Dow-FilmTec with flat sheet configuration having an active surface area of 59 cm. For high pressure RO experiments SWHR and BW-30 flat sheet membranes were used. Similarly, NF90 and NF 270, two dense nanofiltration membranes were used for low pressure RO experiments. 

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