Single and Binary Competitive Adsorption of Cobalt and Nickel onto Novel Magnetic Composites Derived from Green Macroalgae

摘要

Easily separated novel magnetic composite, derived from a kind of green macroalgae—Enteromorpha prolifera, was employed for effective adsorption of radioactive cobalt (60Co) and nickel (63Ni). The characteristics and adsorption mechanisms of the magnetic E. prolifera composite (MEPE) were investigated by VSM, XRD, FT-IR, SEM, TEM, BET, and XPS. The results indicated that the saturated magnetization exceeded 4.90 emu/g. The surface area and average pore diameter of MEPE were 10.995 m2/g and 5.49 nm, respectively. The biosorbent had a good affinity to both Co(II) and Ni(II) with the maximum adsorption capacity of 135 and 137 mg/g, respectively. Coexisting nonradioactive ions, like Na+, K+, Mg2+, and Ca2+, affected the sequestration of Co and Ni to a limited degree. Compared with the single-component system, the uptake of Co(II)/Ni(II) for the binary-component adsorption decreased due to competitive adsorption. The potential mechanism of Co(II)/Ni(II) removal by MEPE was mainly electrostatic attraction and surface complex formation. Hydroxyl groups and amine groups in MEPE could be involved in the reaction and adsorption process, and the novel biosorbent MEPE could achieve rapid separation from radioactive wastewaters and effective uptake of Co(II) and Ni(II) simultaneously.