Polyamide membranes estimates

Table 7.4 Determination of effective pore radii and effective areas for permeation at pH 4 and 7 through pH-sensitive polyamide membranes estimated by Eq. (7.1)...

A third relevant factor is the chemical composition of the membranes, with cellulose acetate, polyamide and a number of composite membranes sharing the seawater installed capacity. It is my estimate that polyamide membranes have at least 90% of the market. 

Z.V.P. Murthy, S.K. Gupta, Sodium cyanide separation and parameter estimation for reverse osmosis thin-film composite polyamide membrane,... 

Table 6 lists the AC percentage for both polyamide/polysulfone membranes the N/0 ratio indicates an excess of oxygen atoms for the commercial membrane and a defeet of oxygen for the experimental one with respect to theoretical polyamide value ((N/0) = 1). Sinee the presence of polyamide non-characteristic elements was very low, impurities or rare chemicals must contain the same type of atoms than polyamide, which can be estimated by curve fitting of the core-level speetra. 

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