Preliminary study of doxycycline adsorption from aqueous solution on alkaline modified biochar derived from banana peel
Van-Truc Nguyen, Thanh-Binh Nguyen, Thi-Dieu-Hien Vo, Nguyen Duy Dat, Thi-Kim Quyen Vo, Xuan Cuong Nguyen, Viet-Cuong Dinh, Thi-Ngoc-Chau Le, Thi-Giang-Huong Duong, Ha Manh Bui, Xuan‐Thanh Bui
Abstract
This study explores the adsorption of doxycycline (DOX) from aqueous solutions onto biochar derived from banana peel, which was prepared using a potassium hydroxide activation method (KOH-BPB). The biochar properties were characterized based on morphology, surface area (SBET of 710.241 m<sup>2</sup> g<sup>-1</sup>), functional groups, and surface charge (pHPZC = 7.7). Parameters, including initial pH, DOX concentration, and ionic strength, that influenced the DOX adsorption capacity of KOH-BPB were examined. Adsorption equilibrium of DOX on KOH-BPB was assessed through four isothermal models: the Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich models. The obtained data were most compatible with the Langmuir model (R<sup>2</sup> = 0.9879). KOH-BPB has a maximum DOX absorption capacity of 121.95 mg g<sup>-1</sup> which exceeds that of many comparable absorbents. The maximum DOX removal was 96.7% at pH 6, a DOX concentration of 20 mg L<sup>-1</sup>, and a KOH-BPB dose of 1.0 g L<sup>-1</sup>. These findings reveal that biochar from banana peel effectively removes antibiotic residues from water. This study provides a potential, low-cost, and environmentally friendly adsorbent.