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

Biosourced choline-functionalized sawdust for dual dye removal: ion-exchange versus multifactorial adsorption mechanisms

Meriem Bendjelloul, El Hadj Elandaloussi, Fatima Zahra Benhachem, Abdelkarim Seghier, and Ahmed Boucherdoud

Environment and Sustainable Development Laboratory, University of Relizane, Bourmadia, Relizane, Algeria

E-mail: elhadj.elandaloussi@univ-relizane.dz

Received: 17 April 2026  Accepted: 11 May 2026

Abstract:

Choline-functionalized sawdust (CFS) was developed as a sustainable biosorbent for the removal of structurally distinct dyes from aqueous solutions, addressing the urgent need for low-cost, bio-based alternatives to conventional treatment methods. The valorization of lignocellulosic waste into functionalized adsorbents contributes to circular economy strategies and provides an eco-friendly solution for dye pollution. Adsorption studies revealed dual mechanistic pathways in single-component systems: Indigo Carmine (IC) uptake is dominated by sulfonate–ammonium ion exchange, producing rapid kinetics, and exothermic thermodynamics, whereas Methylene Blue (MB) removal proceeds through multifactorial interactions, resulting in slower kinetics, and entropy-driven adsorption. Langmuir isotherms yielded q_max values of 125 mg·g^‒1 for IC and 43.1 mg·g^‒1 for MB, while complementary nonlinear models highlighted the monomechanistic nature of IC adsorption versus the heterogeneous, energetically variable uptake of MB. Adsorption was largely insensitive to ionic strength, underscoring robustness under saline conditions. Regeneration experiments confirmed recyclability, with IC uptake reversed by NaOH and MB restored by NaCl. Overall, CFS emerges as a cost-effective, bio-based adsorbent derived from lignocellulosic waste, combining dual adsorption capacity, ionic strength resilience, and regeneration efficiency, making it a promising candidate for sustainable wastewater treatment.

Keywords: Lignocellulosic waste valorization; Dye adsorption; Ion-exchange mechanism; Multifactorial interactions; Ionic strength resilience; Sustainable wastewater treatment

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-05052-5

Chemical Papers 80 (9) 10891–10906 (2026)