New factorial designs to evaluate chemisorption of divalent metals on aminated silicas

Adsorption processes of Cu(II), Co(II), and Hg(II) on two aminated silica g el surfaces with immobilized ethylenediamine and diethylenediamine groups w ere studied by a new 2(3) full factorial design. Two metal quantity levels, temperatures of 25 and 50 degreesC, and silica amounts of 100 and 200 mg w ere employed. Our study indicates that higher factorial design levels incre ase adsorption for all metals evaluated, with the exception of the mass par ameter. Adsorption is also significantly affected by important antagonistic and synergistic effects involving all factors. Both functionalized silica gel surfaces present higher interactions and good perspectives in preconcen tration studies for mercury. The factorial design results are also discusse d in terms of some solvation properties for each of the metals studied. (C) 2001 Academic Press.