From alkali-treated spectrum

Fig. 2. Ultraviolet absorption spectra of a copolymer of aspartic acid and histidine before and after heating or after treating with alkali. The spectrum of the alkali-treated sample was not significantly affected by heating. Taken from Rohlfing and Fox (16).

Table 7.24 shows where nanofiltration fits in the spectrum of specialized membrane filtration processes. The process has application regardless of the type of chlor-alkali cell in use, and it also can remove sulfate from chlorate plant liquors. The membranes used in the filters are sensitive to free chlorine. In a membrane-cell plant, therefore, the filter usually will treat a sidestream of fully dechlorinated brine. After standard filtration and. 

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