Polyacrylonitrile Composites of Ag–Al–Si–O Aerogels and Xerogels as Iodine and Iodide Sorbents

Abstract

Mechanically robust engineered sorbents were constructed by embedding Ag-loaded aerogels or xerogels in a polyacrylonitrile (PAN) matrix at 30 or 50 mass% loadings of gel in PAN. The processes for making the base gels, Ag-exchanging the base gels, and making the PAN-gel composite materials are described herein. The composite technology is very flexible for making hybrid sorbents using various inorganic or organic active sorbents. The PAN-gel composite materials were evaluated for iodine uptake in the form of gaseous iodine [I2(g)] at room temperature and at 150 °C as well as iodide (I–) at room temperature from simulated liquid nuclear wastes. The composites show high I2(g) uptake and high I– uptake (≥93 mass%) in simulated liquid secondary waste spiked with 5 mg L–1 I–. These results demonstrate the utility of these composite forms for iodine removal from contaminated gas and liquid streams.