In this work, Fe-Mn magnetic adsorbent was used to remove mercury from wastewater. This research characterizes the structural properties of the adsorbent and also investigates the effects of the operating conditions to evaluate the adsorbent effectiveness for water treatment applications. In the adsorbent preparation stage, the MnCl2 concentration in the solution was chosen at 0.03 mol/L to synthesize the best adsorbent. The structural properties of the Fe-Mn magnetic adsorbent were examined through SEM, ICP, FTIR, XRD, and VSM analyses. XRD results confirmed the presence of FeMnO4 and Fe3O4. VSM showed the superparamagnetic properties of the adsorbent. The influences of the solution pH, Hg (II) initial concentration, adsorption time, and adsorbent dose were explored. The mercury removal of 99% occurred at 30 min, Hg (II) initial concentration 42 mg/L, pH 6, and adsorbent dose of 4.4 g/L. The pseudo-second order kinetic fitted better to the experimental data. The Langmuir isotherm also suitably corresponded to the data. The maximum Hg (II) adsorption capacity of Fe-Mn magnetic adsorbent was 5.408 mg/g. The positive changes of the Gibbs free energy indicated that the adsorption process was endothermic and spontaneous. Overall, Fe-Mn magnetic adsorbent exhibits commendable performance in removing mercury from wastewater.
