Synthesis and Characterization of Hausmannite‐Activated Carbon Nanocomposites for Removal of Lead from Aqueous Solutions

Nano-hausmannite (Mn3O4; NH) was prepared together with its composites with activated carbon (AC), namely, HAC-1 and HAC-2. These materials were characterized by different techniques, and the adsorption properties of the studied sorbents NH, AC, HAC-1, and HAC-2 for Pb(II) were evaluated considering the effects of shaking time, pH, sorbent weight, initial Pb(II) concentrations, and temperature using batch experiments. The kinetics of sorption was described by the pseudo-first-order model. The adsorption isotherm was well fitted to the Sips model. The adsorption process was endothermic. Desorption experiments indicated that Pb(II) was released from the loaded adsorbents: NH, AC, HAC-1, and HAC-2 using 1.0 M HCl (97 % efficiency). Infrared spectral analysis suggested adsorption of Pb(II) through chemical bonding between the negatively charged functional groups of Mn-O, Mn-O-Mn, OH, and COO- with Pb(II).