Anions in trade effluents - Determination of Anions in Natural and Treated Waters - page 583

Chapter 10
Anions in trade effluents
10.1 Borate
10.1.1 Spectrophotometric method
The standard curcumin method [1,2] has been found to be suitable for the determination
of borate in industrial effluents.
10.1.2 Ion chromatography
Hill and Lash [3] have described an ion chromatographic method for the determination of
down to 0.05mg L −1 of borate in environmental waters, nuclear fuel dissolvent solutions
and effluents.
Borate is selectively concentrated on Amberlite XE-243 ion exchange resin and
converted to tetrafluoroborate using 10% hydrofluoric acid. Tetrafluoroborate is strongly
retained by the resin, thus allowing excess fluoride to be eluted without loss of boron.
The tetrafluoroborate is eluted with 1M sodium hydroxide and is determined in the eluant
by ion chromatography. Boron is quantified to a lower limit of 0.05mg L −1 .
None of the common ions interferes at a 100 to 1 mole ratio to boron. In addition, at
least a 280 to 1 mole ratio of fluoride to boron, as well as a 100 to 1 mole ratio of
chloride to boron, can be tolerated. Fig. 10.1 shows an ion chromatogram of a sample
which initially contained sulphate, chloride, nitrate, fluoride and chromate at a 100 to 1
mole ratio and which was prepared according to the standard procedure. As shown,
tetrafluoroborate peaks are well resolved from all the residual amounts of these anions
not completely removed by the XE-243 column treatment.
10.2 Bromide
10.2.1 Ion chromatography
Applications of ion chromatography to the determination of bromide in treated waters are
reviewed in Table 10.1 and discussed further under multianion analysis in sections
10.22.1, 12.8.1 and 12.8.2.