What question did this study set out to answer?

The aim is to convert apple pruning residues into adsorbents for dye-contaminated water, optimizing their efficiency.

March 6, 2026Recycling0 citationsOpen Access

Apple Pruning-Derived Activated Biochar and Hydrochar for Efficient Dye Adsorption: Response Surface Methodology-Guided Optimization, Kinetic Analysis, and Mechanistic Modelling

ASAmeni Ben SalahUniversity of the Basque Country MAM. Mirari Antxustegi ECEriz CorroUniversity of the Basque Country

Key Points

The aim is to convert apple pruning residues into adsorbents for dye-contaminated water, optimizing their efficiency.
Produced activated biochars using single-step and two-step KOH activation.
Characterized materials with FTIR spectroscopy, SEM imaging, and N2 adsorption–desorption.
Conducted batch adsorption experiments using methylene blue dye across various concentrations.
Analyzed kinetic and adsorption isotherm models to understand adsorption mechanisms.
Activated biochars showed superior dye adsorption performance compared to activated hydrochar.
ABC-2S had higher monolayer adsorption capacities (up to 22.9 mg/g) than activated hydrochar (9.7 mg/g).
Adhesion mechanisms indicated external mass transfer influences and complex kinetics described by the Avrami model.
Adsorption stability confirmed with nearly complete dye removal over three regeneration cycles.

Abstract

This study explores the valorisation of apple pruning (AP) residues into sustainable carbonaceous adsorbents for dye-contaminated wastewater. Activated biochars (ABCs) were produced via single-step (ABC-1S) and two-step (ABC-2S) KOH activation, while activated hydrochar (AHTC) was obtained through hydrothermal carbonization followed by H3PO4 activation. The materials were comprehensively characterized using proximate analysis, FTIR spectroscopy, SEM imaging, and N2 adsorption–desorption to evaluate surface chemistry, morphology, and textural properties. Batch adsorption experiments using MB (5–100 mg/L) demonstrated the superior performance of ABCs compared to AHTC. At low dye concentrations, adsorption on ABCs was partially influenced by external mass transfer, while kinetic data were best described by the Avrami model, indicating complex adsorption mechanisms. Isotherm analysis showed that ABC-2S exhibited heterogeneous adsorption behaviour, whereas AHTC poorly conformed to conventional isotherm models. The Langmuir model indicated higher monolayer capacities for ABCs (up to 22.9 mg/g) relative to AHTC (9.7 mg/g), reflecting a greater density of accessible adsorption sites induced by alkaline activation. Notably, nearly complete methylene blue (MB) removal was maintained over three regeneration cycles, confirming the stability, reusability, and practical potential of AP-derived ABCs and AHTC for sustainable wastewater treatment.

Demander à l'IA

Bookmark

View Full Paper