Mp. Elizalde-gonzalez et al., Application of natural zeolites for preconcentration of arsenic species inwater samples, J ENVIR MON, 3(1), 2001, pp. 22-26
Zeolites of the clinoptilolite type produced in Mexico and Hungary were inv
estigated with respect to their sorption efficiency for various redox speci
es of arsenic. Long-term experiments showed that arsenate remains stable fo
r a long period in spiked deionised water and drinking water, as well as in
the surface water of the Biela valley in Saxony, Germany. Both clinoptilol
ites are able to decrease the initial arsenic concentration of 200 mug l(-1
) by more than 75% in deionised, drinking, ground and sur face waters. In t
he case of the Mexican zeolite, both the arsenite and the arsenate concentr
ations (200 mug l(-1))can be lowered from 200 mug l(-1) to 10 mug l(-1) whi
ch is the World Health Organisation's (WHO's) recommended maximum level. It
was found that the presence of cations and anions in the natural waters of
Biela, Germany, and Zimapan, Mexico, did not reduce the efficiency of the
selected zeolites. The Hungarian zeolite removed 75% of the arsenate in the
Zimapan water and only 50% when the sample was first acidified. This zeoli
te totally desorbed the fixed arsenic into a water volume that was half the
volume in the adsorption experiment.