The removal of Pb (II) by La-MgFe2O4 and its phosphorus-removal waste from aqueous solution

Abstract

Adsorption is an economical and effective method to remove heavy metal ions in polluted sewage. This study investigates the Pb(II) removal performance, mechanism, environmental safety and magnetic separation from aqueous solution by the lanthanum-supported magnesium ferrite (La@MgFe2O4) and its phosphorus-removal waste (La-P@MgFe2O4). The results show that at 25°C and pH 5 the maximum adsorption capacity of La@MgFe2O4 and La-P@MgFe2O4 are 326.18 mg/g and 28.74 mg/g respectively. When the dosage of the two adsorbents is 1.0g/L separately and the concentration of Pb(II) is 10mg/L, Pb(II) is absorbed completely within 60min and 120min respectively. The adsorption capacity is positively correlated with the amount of -OH on the adsorbents surface. The complexation of La@MgFe2O4 and Pb(II) overcomes their electrostatic repulsion, while La-P@MgFe2O4 remove Pb(II) by electrostatic attraction and complexation. The experiment with beneficiation wastewater confirms the removal performance of heavy metals ions related to the two adsorbents. The study shows that both La@MgFe2O4 and La-P@MgFe2O4 are stable recyclable adsorbents without secondary pollution and are easy to separate from aqueous solution in an external magnetic field.