Clearance and recovery of Cd(II) from aqueous solution by magnetic separation technology

An effective method to actualize the recycling use of Cd(II) in industrial wastewater was developed by using the magnetic beads, which was modified with ethylenediamine. When the industrial wastewater was treated with these magnetic beads, the Cd(II) concentration in the solution was sharply reduced to the governmental standard (0.1 μg mL−1) of China. Based on the monolayer adsorption of Cd(II) on the surface of these magnetic beads, the saturation capacity for Cd(II) reached to 68 mg g−1 dried magnetic beads. On the other hand, the binding Cd(II) could be easily recovered in acid conditions and the recovery efficiency exceeded 99%. Thus, in the process of the wastewater purification, the recycling utilization of Cd(II) was realized. Additionally, the excellent capability of regeneration and recycling utilization of these magnetic beads made this technology much suitable for the large-scale application. Compared with the conventional purification methods, the rapid process, simple equipments, easy operation and high efficiency, brought this technology with great potentialities in the treatment of industrial wastewater.

► A technology based on magnetic beads was developed to recycle Cd2+ from wastewater.
► After the adsorption, the Cd2+ concentration was sharply reduced to 0.1 μg mL−1.
► The saturation capacity reached to 67.7 mg g−1 and clearance rate was 99.5%.
► The recovery efficiency of Cd2+ could exceed 99% in mild conditions.
► The excellent reusability of magnetic beads makes this technology more efficient.