Enhanced removal of radioactive iodine anions from wastewater using modified bentonite: Experimental and theoretical study

Junqiang Yang; Wenya Tai; Fei Wu; Keliang Shi; Tianyi Jia; Yin Su; Tonghuan Liu; Pavle Mocilac; Xiaolin Hou; Ximeng Chen

doi:10.1016/j.chemosphere.2021.133401

Enhanced removal of radioactive iodine anions from wastewater using modified bentonite: Experimental and theoretical study

Chemosphere. 2022 Apr:292:133401. doi: 10.1016/j.chemosphere.2021.133401. Epub 2021 Dec 22.

Authors

Junqiang Yang¹, Wenya Tai², Fei Wu³, Keliang Shi⁴, Tianyi Jia², Yin Su², Tonghuan Liu⁵, Pavle Mocilac¹, Xiaolin Hou¹, Ximeng Chen⁵

Affiliations

¹ Frontier Science Center for Rare Isotopes, Lanzhou University, 730000, Lanzhou, PR China; School of Nuclear Science and Technology, Lanzhou University, 730000, Lanzhou, PR China.
² School of Nuclear Science and Technology, Lanzhou University, 730000, Lanzhou, PR China.
³ Frontier Science Center for Rare Isotopes, Lanzhou University, 730000, Lanzhou, PR China.
⁴ Frontier Science Center for Rare Isotopes, Lanzhou University, 730000, Lanzhou, PR China; School of Nuclear Science and Technology, Lanzhou University, 730000, Lanzhou, PR China; Key Laboratory of Special Function Materials and Structure Design, Ministry of Education, Lanzhou University, 730000, Lanzhou, PR China. Electronic address: shikl@lzu.edu.cn.
⁵ Frontier Science Center for Rare Isotopes, Lanzhou University, 730000, Lanzhou, PR China; School of Nuclear Science and Technology, Lanzhou University, 730000, Lanzhou, PR China; Key Laboratory of Special Function Materials and Structure Design, Ministry of Education, Lanzhou University, 730000, Lanzhou, PR China.

PMID: 34953880
DOI: 10.1016/j.chemosphere.2021.133401

Abstract

Efficient and cost-effective removal of radioactive iodine anions from contaminated water has become a crucial task and a great challenge for waste treatment and environmental remediation. Herein, we present hexadecylpyridinium chloride monohydrate modified bentonite (HDPy-bent) for the efficient and selective removal of iodine anions (I^- and IO₃^-) from contaminated water. Batch experiments showed that HDPy-bent could remove more than 95% of I^- and IO₃^- within 10 min, and had maximum I^- and IO₃^- adsorption capacities of 80.0 and 50.2 mg/g, respectively. Competitive experiments indicated that HDPy-bent exhibited excellent I^- and IO₃^- selectivity in the excessive presence of common concomitant anions including PO₄^3-, SO₄^2-, HCO₃^-, NO₃^-, Cl^- (maximum mole ratio of anions vs iodine anions was ∼50,000). An anion exchange mechanism was proposed for the selective adsorption of iodine anions. Optimal adsorption structure of HDPy⁺/I^- (IO₃^-) at atomic level and driving forces of the I^- (IO₃^-) adsorption were calculated by density functional theory (DFT) simulations. Moreover, the good durability and reusability of the HDPy-bent has been demonstrated with 5 adsorption-desorption cycles. Dynamic column experiment also demonstrated that HDPy-bent exhibited excellent removal and fractional recovery capabilities towards I^- and IO₃^- from simulated groundwater and environmental water samples. In conclusion, this work presents a promising adsorbent material for the decontamination of radioactive iodine anions from wastewater on a large scale.

Keywords: Adsorption; Density functional theory; Modified bentonite; Radioactive iodine; Wastewater.

MeSH terms

Adsorption
Anions
Bentonite
Humans
Iodides
Iodine Radioisotopes
Models, Theoretical
Thyroid Neoplasms*
Wastewater
Water Pollutants, Chemical* / analysis

Substances

Anions
Iodides
Iodine Radioisotopes
Waste Water
Water Pollutants, Chemical
Bentonite