Co-pyrolyzed sawdust–polypropylene biochar as a sustainable adsorbent for heavy-metal removal in wastewater
4 affiliations
- 1School of Energy and Environment, University of Phayao, Phayao, 56000, Thailand
- 2Faculty of Engineering, Mahasarakham University, Khamriang, 44150, Mahasarakham, Thailand
- 3Faculty of Liberal Arts and Science, Chaiyaphum Rajabhat University, Chaiyaphum, 3600, Thailand
- 4Faculty of Public Health, Burapha University, Chonburi, 20131, Thailand
Abstract
Co-pyrolysis of lignocellulosic sawdust and non-recyclable polypropylene waste provides a biorefinery-driven pathway for producing high-performance biochar while simultaneously valorizing forestry residues and plastic waste. Mixed sawdust-PP feedstocks were thermochemically converted at 300, 400, and 500 °C using a semi-continuous LPG-fired reactor designed for rural Thai communities. Physicochemical characterization revealed a clear temperature-dependent structural evolution from cellulose-rich matrices to carbon-dense, partially graphitic frameworks with enhanced aromaticity and pore accessibility, while the BET surface area varied in the low range (~ 102–166 m² g⁻¹) due to plastic-induced pore masking. The surface pH pzc shifted toward near-neutral values (~ 6.0–6.2) with increasing temperature, enhancing electrostatic interactions with Cu²⁺. Copper adsorption performance increased markedly with temperature, with maximum capacities of 85.4 mg g⁻¹ (300 °C), 111.7 mg g⁻¹ (400 °C), and 126.1 mg g⁻¹ (500 °C). Kinetic analysis showed that fractal-like and general-order models (R² > 0.99) best described the adsorption behavior, confirming heterogeneous and diffusion-influenced chemisorption. The Redlich–Peterson and Liu isotherms provided the best equilibrium fits, indicating adsorption on energetically heterogeneous surfaces. Thermodynamic parameters verified that the adsorption process was spontaneous, endothermic, and entropy driven. The SPB produced at 500 °C retained over 73% of its initial removal efficiency after five regeneration cycles, demonstrating strong operational stability. Overall, these results establish co-pyrolyzed sawdust–PP biochar as a cost-effective, activation-free adsorbent aligned with circular bioeconomy and biorefinery strategies, supporting decentralized wastewater treatment and contributing to SDGs related to clean water, responsible production, and climate action.
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BibTeX
@article{kreetachat2026copyrolyzed,
title = {{Co-pyrolyzed sawdust–polypropylene biochar as a sustainable adsorbent for heavy-metal removal in wastewater}},
author = {Torpong Kreetachat and Saksit Imman and Nopparat Suriyachai and Suphalerk Khaowdang and Aitsara Chanthakhot and Athicha Janthakhot and Surachai Wongcharee and Worachate Sangsida and Sukanya Hongthong and Kowit Suwannahong},
journal = {Applied Water Science},
year = {2026},
month = jun,
doi = {10.1007/s13201-026-02908-9},
url = {https://doi.org/10.1007/s13201-026-02908-9},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Co-pyrolyzed sawdust–polypropylene biochar as a sustainable adsorbent for heavy-metal removal in wastewater
AU - Torpong Kreetachat
AU - Saksit Imman
AU - Nopparat Suriyachai
AU - Suphalerk Khaowdang
AU - Aitsara Chanthakhot
AU - Athicha Janthakhot
AU - Surachai Wongcharee
AU - Worachate Sangsida
AU - Sukanya Hongthong
AU - Kowit Suwannahong
PY - 2026
DA - 2026/06/21
JO - Applied Water Science
DO - 10.1007/s13201-026-02908-9
UR - https://doi.org/10.1007/s13201-026-02908-9
AB - Co-pyrolysis of lignocellulosic sawdust and non-recyclable polypropylene waste provides a biorefinery-driven pathway for producing high-performance biochar while simultaneously valorizing forestry residues and plastic waste. Mixed sawdust-PP feedstocks were thermochemically converted at 300, 400, and 500 °C using a semi-continuous LPG-fired reactor designed for rural Thai communities. Physicochemical characterization revealed a clear temperature-dependent structural evolution from cellulose-rich matrices to carbon-dense, partially graphitic frameworks with enhanced aromaticity and pore accessibility, while the BET surface area varied in the low range (~ 102–166 m² g⁻¹) due to plastic-induced pore masking. The surface pH pzc shifted toward near-neutral values (~ 6.0–6.2) with increasing temperature, enhancing electrostatic interactions with Cu²⁺. Copper adsorption performance increased markedly with temperature, with maximum capacities of 85.4 mg g⁻¹ (300 °C), 111.7 mg g⁻¹ (400 °C), and 126.1 mg g⁻¹ (500 °C). Kinetic analysis showed that fractal-like and general-order models (R² > 0.99) best described the adsorption behavior, confirming heterogeneous and diffusion-influenced chemisorption. The Redlich–Peterson and Liu isotherms provided the best equilibrium fits, indicating adsorption on energetically heterogeneous surfaces. Thermodynamic parameters verified that the adsorption process was spontaneous, endothermic, and entropy driven. The SPB produced at 500 °C retained over 73% of its initial removal efficiency after five regeneration cycles, demonstrating strong operational stability. Overall, these results establish co-pyrolyzed sawdust–PP biochar as a cost-effective, activation-free adsorbent aligned with circular bioeconomy and biorefinery strategies, supporting decentralized wastewater treatment and contributing to SDGs related to clean water, responsible production, and climate action.
SN - 2190-5487
SN - 2190-5495
ER -