Synthesis of palygorskite based microspheres for efficient and recyclable simultaneous removal of radioactive iodine and iodide

The valence state of radioactive iodine is abundant and convertible. Therefore, it is crucial to synthesize a cost-effective, recyclable adsorbent that can effectively and simultaneously remove polyvalent radioactive iodine. Polymerized microsphere adsorbents (PMs) with pore size of 10 ∼ 20 μm and surface of palygorskite (PAL) were prepared by the Pickering emulsion template method using dimethylaminoethyl methacrylate (DMAEMA) as functional monomer and affordable PAL as matrix material. Under the synergistic effect of chemical adsorption of tertiary amine group in PDEAEMA and physical adsorption, the optimized PM-2 exhibits excellent adsorption activities for gaseous iodine (2.98 g/g), iodine in n-hexane (1.39 g/g), and iodide (1.48 mmol/g). After heating and soaking in NaOH solution, the high adsorption capacity and almost unchanged morphology and crystal structure of PM-2 after 5 cycles indicate that PMs have outstanding physical and chemical stability and reusability. Importantly, PMs also show astonishing adsorption activity for the simultaneous removal of iodine and iodide. Moreover, the ultra-fast adsorption rate and ultra-high adsorption efficiency of PMs provide promising results for the removal of polyvalent radioactive iodine in environmental remediation.