Studies on adsorption properties of magnetic composite prepared by one-pot method for Cd(II), Pb(II), Hg(II), and As(III): Mechanism and practical application in food.

A one-pot synthesis afforded a magnetic, crosslinked polymer adsorbent (m-P6) with a variety of functional groups to realize simultaneous adsorption of Cd, Pb, Hg, and As. The material was characterized by TEM-EDS, XRD, FT-IR, VSM, and XPS. Kinetic and isothermal analyses suggested mainly chemisorption processes of heavy metal ions that form multiple layers on heterogeneous surfaces. Theoretical adsorption capacities calculated by a pseudo-2nd-order kinetic model and the Sips isothermal model were 282.88 mg/g for Cd, 326.18 mg/g for Pb, 117.85 mg/g for Hg, and 320.29 mg/g for As. m-P6 not only can efficiently adsorb divalent heavy metals (Cd, Pb, Hg), but also demonstrate a process of adsorption-driven catalytic oxidation by single-electron transfer (SET) from As to As. In application, in addition to adsorption in water, m-P6 is capable of minimizing matrix interference, and extracting trace heavy metals in a complex environment (cereal) through easy operations for improving the detection accuracy, as well as it is potential for application in detection of trace heavy metals in foodstuffs. m-P6 can be readily regenerated and efficiently recycled for 5 cycles using eluent E12 and dilute acid.