Construction of camphor leaves-derived biochar@bismuth for the capture of gaseous iodine

Herein, Bi2O3 loaded with camphor leaves-derived biochar (Bi2O3@CLBC) was prepared to capture gaseous iodine. Bi2O3@CLBC was provided with a loose structure, high reactivity and relatively good thermal stability, leading to a high uptake capacity. The capture behavior of iodine on Bi2O3@CLBC was well described by the Pseudo-first-order and Langmuir models, demonstrating the occurrence of monolayer chemisorption on Bi2O3@CLBC. The maximum adsorption amount of Bi2O3@CLBC for iodine was 885.8 mg/g. The chemical uptake played a leading role in capturing volatile iodine, including the direct reaction between Bi2O3 particles and iodine vapor and the charge transfer between the –OH on biochar and iodine to generate a coordination complex. The pores on the surface of biochar could also capture some iodine through physical adsorption. In one word, this work was expected to offer a green treatment method for the excess of camphor leaves and an exceptional adsorbent for iodine uptake from spent fuel.