Adsorption of Hg(II) on polyethyleneimine-functionalized carboxymethylcellulose beads: Characterization, toxicity tests, and adsorption experiments

Suk-Hyun Yoo; Seung-Chan Lee; Mingi Ko; Soyeong Yoon; Jooyoung Lee; Jeong-Ann Park; Song-Bae Kim

doi:10.1016/j.ijbiomac.2023.124516

Adsorption of Hg(II) on polyethyleneimine-functionalized carboxymethylcellulose beads: Characterization, toxicity tests, and adsorption experiments

Int J Biol Macromol. 2023 Jun 30:241:124516. doi: 10.1016/j.ijbiomac.2023.124516. Epub 2023 Apr 21.

Authors

Suk-Hyun Yoo¹, Seung-Chan Lee¹, Mingi Ko², Soyeong Yoon², Jooyoung Lee², Jeong-Ann Park², Song-Bae Kim³

Affiliations

¹ Environmental Functional Materials and Water Treatment Laboratory, Department of Rural Systems Engineering, Seoul National University, Seoul, Republic of Korea.
² Department of Environmental Engineering, Kangwon National University, Gangwon, Republic of Korea.
³ Environmental Functional Materials and Water Treatment Laboratory, Department of Rural Systems Engineering, Seoul National University, Seoul, Republic of Korea; Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea. Electronic address: songbkim@snu.ac.kr.

PMID: 37086762
DOI: 10.1016/j.ijbiomac.2023.124516

Abstract

Mercury (Hg) is widely used in many industrial processes and is released into the environment. Therefore, efficient removal of Hg from water is of vital importance worldwide. Here, we explored the adsorption characteristics of Hg(II) on polyethyleneimine-functionalized carboxymethylcellulose (PEI-CMC) beads and studied the toxicity of the beads toward Daphnia magna and Pseudokirchneriella subcapitata. The PEI-CMC beads had an average particle size of 2.04 ± 0.25 mm, a point of zero charge (pH_pzc) of 5.8, and a swelling ratio of 2.45. Acute toxicity tests demonstrated that the PEI-CMC beads had no toxic effects on D. magna. The growth inhibition tests revealed that growth inhibition of P. subcapitata could be attributed to adsorption of trace elements in growth media on the PEI-CMC beads. The adsorption experiments exhibited that the Matthews and Weber model best described the kinetic data, whereas the Redlich-Peterson model was well fitted to the isotherm data. The theoretical maximum Hg(II) adsorption capacity of the PEI-CMC beads was 313.1 mg/g. The thermodynamic experiments showed endothermic nature of the Hg(II) adsorption on the PEI-CMC beads at 10-40 °C. The adsorption experiments exhibited that the Hg(II) adsorption capacity decreased gradually as pH increased from 2 to 12. The adsorption of Hg(II) on the PEI-CMC beads can occur through chelation and electrostatic attraction. The FTIR and XPS spectra before and after Hg(II) adsorption confirmed that chelation of neutral Hg(II) species (HgCl₂, HgClOH, and Hg(OH)₂) can occur with amino and oxygen-containing functional groups on the PEI-CMC beads. Considering species distribution of Hg(II) and the pH_pzc of the PEI-CMC beads, electrostatic attraction between the positively-charged beads and anionic Hg(II) species (HgCl₃^- and HgCl₄^2-) can take place in highly acidic solutions. The PEI-CMC beads were regenerated and reused for Hg(II) adsorption using 0.1 M HCl.

Keywords: Adsorption; Carboxymethylcellulose; Mercury; Polyethyleneimine; Toxicity.

MeSH terms

Adsorption
Carboxymethylcellulose Sodium / chemistry
Hydrogen-Ion Concentration
Kinetics
Polyethyleneimine* / chemistry
Toxicity Tests
Water Pollutants, Chemical* / chemistry
Water Pollutants, Chemical* / toxicity

Substances

Polyethyleneimine
Carboxymethylcellulose Sodium
Water Pollutants, Chemical