ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Radical-assisted hydrothermal treatment coupled with pyrolysis enhances the removal of sulfamethoxazole by porous biochar derived from corn stalk pith

Zhijun Hu, Juntao Zhang, Benmei Wei, Sheng Li, and Yangke Long

Hubei Province Key Laboratory of Agricultural Waste Resource Utilization, School of Chemical and Environmental Engineering, Wuhan Polytechnic University, Wuhan, People’s Republic of China

E-mail: lfrcs@163.com

Received: 27 February 2026  Accepted: 10 May 2026

Abstract:

Porous carbon derived from waste biomass exhibits significant potential for removing environmental contaminants due to its adsorptive properties. However, a structural trade-off exists between achieving the high porosity necessary for optimal adsorption capacity and the high energy consumption with equipment corrosion resulting from the pore-forming process. In this study, a novel strategy based on a free-radical-assisted hydrothermal process was presented for synthesizing porous biochar. Peroxymonosulfate (PMS) serves as the free radical source, enabling controlled oxidation of corn stalk pith during a straightforward hydrothermal pretreatment at 120 °C, followed by carbonization at 700 °C to form internal pores. This innovative approach enhanced the sulfamethoxazole (SMX) adsorption capacity by approximately threefold, from 43.37 mg/g to 130.22 mg/g. Although the PMS-pretreated porous biochar surface displayed superhydrophilic properties due to carboxyl group modification, results analyses indicate that SMX adsorption is primarily driven by π–π conjugation, hydrophobic interactions, and hydrogen bonding, relying on specific surface area rather than electrostatic interactions. This study presents a beneficial attempt at a free-radical-based pretreatment for the straightforward and robust synthesis of porous biochar.

Graphical abstract

Keywords: Biochar; Corn stalk pith; Free radical; Pore formation; Sulfamethoxazole removal

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-05044-5

Chemical Papers 80 (9) 10783–10797 (2026)