Clean application of magnetic biomaterial for the removal of As (III) from water.

Magnetite-coated pine cone biomass was successfully synthesized, characterized, and its interaction with As (III) in water evaluated in order to apply it as an efficient adsorbent. Transmission electron microscope, scanning electron microscope, and imaging studies revealed that spherical magnetite particles were evenly distributed over the pine cone surface. Adsorption studies showed that the optimum pH of As (III) adsorption was 8 and that Fe (III) leaching was negligible at this pH. The optimum Fe3O4:pine cone ratio for As (III) removal was 2.0 g Fe3O4:1.5 g pine cone with adsorption capacity of 13.86 mg/g. The pseudo-second-order model best fitted the kinetic data with activation energy of adsorption was calculated to be 23.78 kJ/mol. The Langmuir isotherm described the equilibrium data best while the values of Dubinin-Radushkevich mean free energy suggests anion-exchange process. Increasing ionic strength slightly increased As (III) capacity of MNP-PCP from 13.86 to 17.82 mg/g at optimum solution pH of 8, but As (III) adsorption reduced by [Formula: see text]anions and humic acid due to competition. Adsorption mechanism was confirmed with evidence from FTIR, XPS, pHPZC, and [Formula: see text] replacement by As (III) adsorption onto the [Formula: see text]-loaded composite.