Synthesis of an eco-friendly calcium-rich biochar: Unveiling the effect of pyrolysis temperature on its properties, phosphorus recovery and involved mechanisms
Abstract
Calcium-modified biochars have attracted considerable attention as promising materials for phosphorus (P) recovery from aqueous effluents. In the current study, marble waste was used as a sustainable alternative to conventional calcium reagents (e.g., CaCl 2 ) and co-pyrolyzed with date palm wastes and poultry manure at 700 • C and 900 • C to produce two Ca-rich biochars, designated as B-700 and B-900. Physico-chemical characterization revealed that increasing the pyrolysis temperature promoted the extensive formation and deposition of calcium-based nanoparticles on the biochar matrix, resulting in significant improvements in structural, textural and surface chemistry properties. For example, the BET surface area and total pore volume of B-900 were 14.4 and 2.5 times greater, respectively, than those of B-700. Consequently, B-900 exhibited excellent P recovery over a wide experimental conditions, achieving a maximum adsorption ability of 146.1 mg g -1 , nearly twice that of B-700 (74.5 mg g -1 ). Comprehensive characterization before and after P recovery demonstrated that P immobilization by B-900 occurred through surface complexation with O-H groups, and predominately, through precipitation as hydroxyapatite (Ca 5 (PO 4 ) 3 OH). In contrast, the lower abundance of calcium oxides on the surface of B-700, favored the formation of brushite (CaHPO 4 ). Besides complexation electrostatic attraction and hydrogen bonding also contributed to P recovery by B-700. The obtained results demonstrated that the co-pyrolysis of organic feedstocks mixed with marble wastes, particularly at temperatures around 900 • C, provides an effective route for producing environmentally-friendly calcium-rich biochars with excellent P recovery performance. The resulting P-loaded biochars can be directly valorized in agriculture as slow-release organic fertilizer, highlighting the potential of this approach to integrate wastewater treatment, nutrient recovery, waste valorization, and circular economy principles.
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BibTeX
@article{jellali2026synthesis,
title = {{Synthesis of an eco-friendly calcium-rich biochar: Unveiling the effect of pyrolysis temperature on its properties, phosphorus recovery and involved mechanisms}},
author = {Salah Jellali and Ahmed Amine Azzaz and Wissem Hamdi and Majida Al-Harassi and Ahmed Al-Raeesi and Imene Bekri-Abbes and Ahmed Al-Sidairi and Jamal Al-Sabahi and Malik Al-Wardy and Mejdi Jeguirim},
journal = {Results in engineering},
year = {2026},
month = aug,
doi = {10.1016/j.rineng.2026.112304},
url = {https://hal.science/hal-05797814v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Synthesis of an eco-friendly calcium-rich biochar: Unveiling the effect of pyrolysis temperature on its properties, phosphorus recovery and involved mechanisms
AU - Salah Jellali
AU - Ahmed Amine Azzaz
AU - Wissem Hamdi
AU - Majida Al-Harassi
AU - Ahmed Al-Raeesi
AU - Imene Bekri-Abbes
AU - Ahmed Al-Sidairi
AU - Jamal Al-Sabahi
AU - Malik Al-Wardy
AU - Mejdi Jeguirim
PY - 2026
DA - 2026/08/01
JO - Results in engineering
DO - 10.1016/j.rineng.2026.112304
UR - https://hal.science/hal-05797814v1
AB - Calcium-modified biochars have attracted considerable attention as promising materials for phosphorus (P) recovery from aqueous effluents. In the current study, marble waste was used as a sustainable alternative to conventional calcium reagents (e.g., CaCl 2 ) and co-pyrolyzed with date palm wastes and poultry manure at 700 • C and 900 • C to produce two Ca-rich biochars, designated as B-700 and B-900. Physico-chemical characterization revealed that increasing the pyrolysis temperature promoted the extensive formation and deposition of calcium-based nanoparticles on the biochar matrix, resulting in significant improvements in structural, textural and surface chemistry properties. For example, the BET surface area and total pore volume of B-900 were 14.4 and 2.5 times greater, respectively, than those of B-700. Consequently, B-900 exhibited excellent P recovery over a wide experimental conditions, achieving a maximum adsorption ability of 146.1 mg g -1 , nearly twice that of B-700 (74.5 mg g -1 ). Comprehensive characterization before and after P recovery demonstrated that P immobilization by B-900 occurred through surface complexation with O-H groups, and predominately, through precipitation as hydroxyapatite (Ca 5 (PO 4 ) 3 OH). In contrast, the lower abundance of calcium oxides on the surface of B-700, favored the formation of brushite (CaHPO 4 ). Besides complexation electrostatic attraction and hydrogen bonding also contributed to P recovery by B-700. The obtained results demonstrated that the co-pyrolysis of organic feedstocks mixed with marble wastes, particularly at temperatures around 900 • C, provides an effective route for producing environmentally-friendly calcium-rich biochars with excellent P recovery performance. The resulting P-loaded biochars can be directly valorized in agriculture as slow-release organic fertilizer, highlighting the potential of this approach to integrate wastewater treatment, nutrient recovery, waste valorization, and circular economy principles.
SN - 2590-1230
ER -