Unraveling the Synergistic Mechanisms of Phosphorus Adsorption and Slow-Release on Low-Mg-Loaded Biochar Enabled by KOH Activation
Fengyun Bu1,2,3, Lei Han4, Hongxia Guo3
1State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
Abstract:
Phosphorus (P) scarcity and pollution demand sustainable recovery strategies. This study engineered a functional straw biochar (F-SBC) from corn straw through synergistic KOH activation and MgCl2 modification for efficient P recovery and slow release. Characterization revealed that KOH pretreatment expanded pore size and enhanced MgO loading. Batch adsorption experiments demonstrated F-SBC achieved a remarkable P adsorption capacity of 24.70 ± 0.57 mg·g-1, and exhibited > 95% removal efficiency across pH 5~9. Adsorption kinetics followed the pseudo-second-order model, and isotherms fitted the Langmuir model, indicating chemisorption-dominated monolayer adsorption. Mechanistic studies identified synergistic contributions from chemical precipitation, inner-sphere complexation, bi-metallic electrostatic attraction, and physical confinement. F-SBC exhibited slow-release properties, alongside sustained adsorption capacity. Competitive anions (HCO3-/CO32-) significantly promoted desorption, while Cl- showed minimal impact. This KOH/MgCl2 co-modification strategy creates a cost-effective, regenerable biochar with superior P recovery and controlled-release potential, advancing sustainable P management from agricultural waste towards a circular bioeconomy.
More Related Videos
09:39Physical, Chemical and Biological Characterization of Six Biochars Produced for the Remediation of Contaminated Sites
Published on: November 28, 2014
10:44Preparation of Biomass-based Mesoporous Carbon with Higher Nitrogen-/Oxygen-chelating Adsorption for CuII Through Microwave Pre-Pyrolysis
Published on: February 12, 2019
Related Concept Videos
The Phosphorus Cycle
Factors Influencing Drug Absorption: Physicochemical Parameters
Enhanced drug absorption can be achieved by reducing particle sizes and increasing surface areas, thereby facilitating...
Extraction: Effects of pH
Phosphorylation
During phosphorylation, protein kinases transfer the terminal phosphate group of ATP to specific amino acid side chains of substrate proteins. Serine, threonine, and tyrosine are the most commonly...
Bioavailability Enhancement: Drug Stability Enhancement and GI Retention
Factors Affecting Dissolution: Drug pKa, Lipophilicity and GI pH
A drug's pKa and the pH of the gastrointestinal (GI) tract play crucial roles...
