Adsorption mechanism of methylene blue by magnesium salt-modified lignite-based adsorbents

Ruzhan Bai; Yan Feng; Lei Wu; Na Li; Quansheng Liu; Yingyue Teng; Runxia He; Keduan Zhi; Huacong Zhou; Xueyan Qi

doi:10.1016/j.jenvman.2023.118514

Adsorption mechanism of methylene blue by magnesium salt-modified lignite-based adsorbents

J Environ Manage. 2023 Oct 15:344:118514. doi: 10.1016/j.jenvman.2023.118514. Epub 2023 Jul 22.

Authors

Ruzhan Bai¹, Yan Feng², Lei Wu³, Na Li⁴, Quansheng Liu⁵, Yingyue Teng⁶, Runxia He⁷, Keduan Zhi⁸, Huacong Zhou⁹, Xueyan Qi¹⁰

Affiliations

¹ College of Chemical Engineering, Inner Mongolia University of Technology, Inner Mongolia Key Laboratory of High-Value Functional Utilization of Low Rank Carbon Resources, Hohhot, 010051, China. Electronic address: 20211800161@imut.edu.cn.
² College of Chemical Engineering, Inner Mongolia University of Technology, Inner Mongolia Key Laboratory of High-Value Functional Utilization of Low Rank Carbon Resources, Hohhot, 010051, China. Electronic address: 1505059136@qq.com.
³ College of Chemical Engineering, Inner Mongolia University of Technology, Inner Mongolia Key Laboratory of High-Value Functional Utilization of Low Rank Carbon Resources, Hohhot, 010051, China. Electronic address: 582188144@qq.com.
⁴ College of Chemical Engineering, Inner Mongolia University of Technology, Inner Mongolia Key Laboratory of High-Value Functional Utilization of Low Rank Carbon Resources, Hohhot, 010051, China. Electronic address: nali87@imut.edu.cn.
⁵ College of Chemical Engineering, Inner Mongolia University of Technology, Inner Mongolia Key Laboratory of High-Value Functional Utilization of Low Rank Carbon Resources, Hohhot, 010051, China. Electronic address: liuqs@imut.edu.cn.
⁶ College of Chemical Engineering, Inner Mongolia University of Technology, Inner Mongolia Key Laboratory of High-Value Functional Utilization of Low Rank Carbon Resources, Hohhot, 010051, China. Electronic address: tengyingyue@163.com.
⁷ College of Chemical Engineering, Inner Mongolia University of Technology, Inner Mongolia Key Laboratory of High-Value Functional Utilization of Low Rank Carbon Resources, Hohhot, 010051, China. Electronic address: 1054260076@qq.com.
⁸ College of Chemical Engineering, Inner Mongolia University of Technology, Inner Mongolia Key Laboratory of High-Value Functional Utilization of Low Rank Carbon Resources, Hohhot, 010051, China. Electronic address: zhikeduan@imut.edu.cn.
⁹ College of Chemical Engineering, Inner Mongolia University of Technology, Inner Mongolia Key Laboratory of High-Value Functional Utilization of Low Rank Carbon Resources, Hohhot, 010051, China. Electronic address: hczhou@imut.edu.cn.
¹⁰ School of Materials Science and Engineering, Hebei University of Engineering, Handan, 056038, China. Electronic address: qixueyan001@163.com.

PMID: 37487308
DOI: 10.1016/j.jenvman.2023.118514

Abstract

The rich pore structure and carbon structure of lignite make it a suitable adsorbent for effectively removing methylene blue (MB) from wastewater. This article reports the preparation of lignite-based adsorbents modified by magnesium salts, and the key factors and adsorption mechanism are analyzed to effectively improve the adsorption performance for MB. The results showed that the lignite was modified by magnesium salts, and the Mg²⁺ in the magnesium salts had a good binding effect on the oxygen-containing functional groups in the lignite. This improved the adsorption performance of the lignite-based adsorbents for MB. The Mg(NO₃)₂-modified lignite-based adsorbent showed the best adsorption performance and removal rate of MB (99.33%) when prepared with 8 wt % Mg(NO₃)₂. Characterization analysis showed that a "-COOMg" structure was formed between Mg²⁺ in the magnesium salts and the carboxylic acid functional group in the lignite, which was postulated to be the absorption site that promoted the adsorption performance for MB. It is speculated that the MB adsorption mechanism of this lignite-based adsorbent is ion exchange.

Keywords: Adsorption mechanism; Lignite-based adsorbents; MB; Magnesium salts; Methylene blue.

MeSH terms

Adsorption
Coal
Hydrogen-Ion Concentration
Kinetics
Magnesium
Methylene Blue* / chemistry
Salts
Water Pollutants, Chemical* / chemistry

Substances

Methylene Blue
Magnesium
Coal
Salts
Water Pollutants, Chemical