Efficient removal of cationic malachite green using co-pyrolyzed corn straw biochar-montmorillonite composites

Xiaodong Yang; Zhiyong Hou; Xuefei Yang; Minghui Li; Yuanxia Guo; Kai Wang; Shuaiqi Luo; Jin Zhao; Pengkai Sun; Qiang Yang; Rui Chen; Yan Yan; Lulu Liu; Lili Wang; Ye Han; Fanming Zeng; Andrew R Zimmerman; Bin Gao

doi:10.1016/j.jenvman.2025.124224

Efficient removal of cationic malachite green using co-pyrolyzed corn straw biochar-montmorillonite composites

J Environ Manage. 2025 Jan 21:375:124224. doi: 10.1016/j.jenvman.2025.124224. Online ahead of print.

Authors

Xiaodong Yang¹, Zhiyong Hou², Xuefei Yang², Minghui Li², Yuanxia Guo², Kai Wang², Shuaiqi Luo², Jin Zhao², Pengkai Sun², Qiang Yang², Rui Chen², Yan Yan², Lulu Liu², Lili Wang², Ye Han², Fanming Zeng³, Andrew R Zimmerman⁴, Bin Gao⁵

Affiliations

¹ Key Laboratory of Materials Design and Quantum Simulation, School of Material Science and Engineering, Changchun University, No.6543 Satellite Road, Changchun, 130022, China. Electronic address: xiaodongyangccu@163.com.
² Key Laboratory of Materials Design and Quantum Simulation, School of Material Science and Engineering, Changchun University, No.6543 Satellite Road, Changchun, 130022, China.
³ School of Materials Science and Engineering, Changchun University of Science and Technology, No.7989 Satellite Road, Changchun, 130022, China.
⁴ Department of Geological Sciences, University of Florida, Gainesville, FL, 32611, USA.
⁵ Department of Civil and Environmental Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA.

PMID: 39842350
DOI: 10.1016/j.jenvman.2025.124224

Abstract

New efficient and sustainable methods for the removal of malachite green (MG) from environmental media are needed. In this study, corn straw was co-pyrolyzed with montmorillonite under a variety of conditions (400, 500, 600, and 700 °C and 10-40 wt% montmorillonite), without any use of toxic chemicals, to produce a series of biochar-clay composites. Characteristics of the composites that make them promising contaminant sorbents include a uniform lamellar-particle micromorphology, enhanced mesoporous structure and surface area (53.0 m² g^-1), and abundant and diverse oxygen/carbon-containing functional groups (i.e., O-H, C-O, C=C, and C-H). The composite produced at 600 °C and 10 wt% montmorillonite had the highest observed MG removal from aqueous solution (6572.1 mg g^-1, 99.6% removal rate). Adsorption of MG by the sorbent was attributed to multiple sorption mechanisms, including physical interaction, cation exchange, and π-π bonding interactions, and was modulated by intra-particle diffusion. This work highlights the potential of corn straw biochar-montmorillonite composites as a favorable adsorbent for environment remediation and water treatment.

Keywords: Adsorption; Biochar; Corn straw; Malachite green; Montmorillonite; Pyrolysis.