2.4. Adsorption isotherm
A series of 100 mL solutions containing Hg2+ and Pb2+ with concentrations
of 0, 1, 2, 4 and 6 mg/L (pH 6.5
±
0.05) were added
with 1 mg of SH-mSi@Fe3O4 and agitated in an rotator oscillator
at 25 ◦C for 5 h to study the adsorption isotherm of the adsorbent.
The solutions were sampled and analyzed as described above.
Langmuir and Freundlich equations were used to evaluate
adsorption isotherm. The Langmuir equation is defined as: