Predicting adsorption of micropollutants on non-functionalized and functionalized multi-walled carbon nanotubes: Experimental study and LFER modeling

Yufeng Zhao; Heqing Tang; Dongfang Wang; Myung-Hee Song; Chul-Woong Cho; Yeoung-Sang Yun

doi:10.1016/j.jhazmat.2021.125124

Predicting adsorption of micropollutants on non-functionalized and functionalized multi-walled carbon nanotubes: Experimental study and LFER modeling

J Hazard Mater. 2021 Jun 5:411:125124. doi: 10.1016/j.jhazmat.2021.125124. Epub 2021 Jan 13.

Authors

Yufeng Zhao¹, Heqing Tang¹, Dongfang Wang², Myung-Hee Song³, Chul-Woong Cho⁴, Yeoung-Sang Yun⁵

Affiliations

¹ Key Laboratory of Resources Conversion and Pollution Control of the State Ethnic Affairs Commission, College of Resource and Environmental Science, South-Central University for Nationalities, Wuhan 430074, Hubei Province, China.
² Hubei Academy of Environmental Sciences, Wuhan 430072, China.
³ Environmental Biotechnology National Research Laboratory, School of Chemical Engineering, Jeonbuk National University (formerly Chonbuk National University), 567 Beakje-dearo, Deokjin-gu, Jeonju, Jeonbuk 54896, Republic of Korea. Electronic address: bsbsmh@jbnu.ac.kr.
⁴ Department of Bioenergy Science and Technology, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186 Republic of Korea. Electronic address: choicejoe@jnu.ac.kr.
⁵ Environmental Biotechnology National Research Laboratory, School of Chemical Engineering, Jeonbuk National University (formerly Chonbuk National University), 567 Beakje-dearo, Deokjin-gu, Jeonju, Jeonbuk 54896, Republic of Korea. Electronic address: ysyun@jbnu.ac.kr.

PMID: 33858098
DOI: 10.1016/j.jhazmat.2021.125124

Abstract

It is of great importance to predict the adsorption of micropollutants onto CNTs, which is not only useful for exploring their potential adsorbent applications, but also helpful for better understanding their fate and risks in aquatic environments. This study experimentally examined the adsorption affinities of thirty-one micropollutants on four multi-walled CNTs (MWCNTs) with different functional groups (non-functionalized, -COOH, -OH, and -NH₂). The properties of each adsorbent were predicted based on the linear free energy relationship (LFER) model. The experimental results showed that MWCNTs-COOH has remarkable adsorption affinities for positively charged compounds (1.996-3.203 log unit), whereas MWCNTs-NH₂ has high adsorption affinities for negatively charged compounds (1.360-3.073 log unit). Regarding neutral compounds, there was no significant difference in adsorption affinities of all types of CNTs. According to modeling results, the adsorption affinity can be accurately predicted using LFER models with R² in the range of 0.81-0.91. Based on the developed models, the adsorption mechanism and contribution of individual intermolecular interactions to the overall adsorption were interpreted. For non-functionalized MWCNTs, molecular interactions induced by molecular volume and H-bonding basicity predominantly contribute to adsorption, whereas for functionalized MWCNTs, the Coulombic interaction due to the charges is an important factor.

Keywords: Ions; LFER; Micropollutants; Multi-walled carbon nanotubes; Pharmaceuticals.

Publication types

Research Support, Non-U.S. Gov't