Sorption and Preconcentration of the Herbicides Atrazine,Simazine, and Ametryne on Montmorillonite

This paper describes the treatment of montmorillonite (MT), with K⁺ (MT_K), Na⁺ (MT_Na), and Ca²⁺ (MT_Ca) to explore the use of these minerals for the extraction and preconcentration of the herbicides atrazine, simazine, and ametryne from aqueous medium. In the sorption process, the three materials exhibited good performance; ametryne was totally sorbed. For atrazine and simazine, MT_K showed a removal between 90% (atrazine) and higher than 99% (simazine). The recoveries employing solutions at initial concentrations of 100 µg L^?1 of each herbicide showed results of 90% (simazine) and 94% (atrazine), whereas for 10 µg L^?1, the results of 73% (simazine) and 81% (atrazine) were obtained. On the other hand, ametryne showed poor recovery values (25 to 40%), probably due to a stronger interaction with MT_K, lowering the recovery values. Based on the results for atrazine and simazine, MT_K presented good features to be used as sorbent phase and for preconcentration, being easily prepared with low cost, demanding low amounts to be used for this purpose, providing fast sorption of atrazine and simazine, and with appropriate recoveries.