Mechanistic study of highly effective phosphate removal from aqueous solutions over a new lanthanum carbonate fabricated carbon nanotube film

Yi Yang; Dachen Liu; Yiliang Chen; Jing He; Qu Li

doi:10.1016/j.jenvman.2024.120938

Mechanistic study of highly effective phosphate removal from aqueous solutions over a new lanthanum carbonate fabricated carbon nanotube film

J Environ Manage. 2024 Apr 25:359:120938. doi: 10.1016/j.jenvman.2024.120938. Online ahead of print.

Authors

Yi Yang¹, Dachen Liu², Yiliang Chen³, Jing He², Qu Li²

Affiliations

¹ Faculty of Arts and Sciences, Beijing Normal University, Zhuhai, 519087, PR China; College of Education for the Future, Beijing Normal University, Zhuhai, 519087, PR China. Electronic address: yiyang@bnu.edu.cn.
² College of Education for the Future, Beijing Normal University, Zhuhai, 519087, PR China.
³ College of Biology and the Environment, Nanjing Forestry University, Nanjing, 210037, PR China.

PMID: 38669888
DOI: 10.1016/j.jenvman.2024.120938

Abstract

The effective purification of phosphate-containing wastewater is considered as increasingly important. In this study, a highly effective LC-CNT film was developed for efficient phosphate removal. Kinetic results showed that the adsorbent exhibited an improved mass transfer efficiency and a fast adsorption rate during adsorption (reaching 80% and 100% equilibrium adsorption capacity within 175 and 270 min, respectively). Kinetic model analysis suggested that the adsorption was a combined chemical physical process. Isotherm study revealed that the LC-CNT film showed a superior adsorption capacity (178.6 mg/g, estimated from the Langmuir model) with multiple adsorption mechanisms. pH study suggested that surface complexation and ligand exchange played important roles during adsorption, and the adsorbent worked well within the pH range of 3-7 with little La leakage. The ionic strength and competing anions showed little influence on the adsorbent effectiveness except for the carbonate and sulfate ions. The characterization and mechanism study revealed that the phosphate adsorption of the LC-CNT film was controlled by inner-sphere complexation, outer-sphere complexation and surface precipitation. The LC-CNT film also showed excellent regenerability and stability in cycling runs, further demonstrating its potential in industrial applications.

Keywords: Carbon nanotube; Lanthanum carbonate; Mechanism; Model analysis; Phosphate adsorption.