High-efficiency radon adsorption by nickel nanoparticles supported on activated carbon

Abstract

Radon (Rn) is a universally known indoor radioactive gas that poses a significant threat to human health. Activated carbon (AC) is the only commercial Rn adsorbent; its adsorption performance is extremely limited due to too few micropores. A series of nickel nanoparticles supported on AC (Ni/AC) composites, combining abundant micropores with open metal sites, is rationally designed for adsorbing Rn via a two-step process consisting of impregnation and high-temperature reduction. The Rn adsorption performance of the Ni/AC composites is obviously improved due to the introduction of nickel nanoparticles. The adsorption coefficient of Ni/AC calcined at 800 °C reaches 6.56 ± 0.14 m³ kg⁻¹ at 25 °C and 1 bar, 48% higher than that of AC. The Ni/AC Rn adsorption coefficient is similar over five cycles. The fine and homogeneous dispersion of nickel nanoparticles, the appropriate chemical state of nickel and the high content of Ni⁰ synergistically promote Rn adsorption on Ni/AC. Experiments verify that Ni/AC composites are a promising candidate for the adsorption of Rn in the atmospheric environment.