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Original Research

Reclaiming phosphate from aqueous solution using biochar derived from anaerobically digested waste activated sludge and its potential as phosphate fertilizer

, , , , &
Article: 2287237 | Received 25 Sep 2023, Accepted 18 Nov 2023, Published online: 27 Nov 2023
 

ABSTRACT

A novel strategy for reclamation and reuse of phosphate from aqueous solution was developed using Mg-enriched biochar prepared from anaerobically digested sludge (ADBC). The ADBC pyrolyzed at 600°C (ADBC-600) exhibited the maximum phosphate removal capacity of 23.2 mg/g, which was much higher than that of raw sludge biocha (10.1 mg/g). Adsorption kinetic and isotherm experiments showed that the adsorption of phosphate on ADBC-600 could be well described by the pseudo-second-order model and Langmuir model, indicating that the adsorption was mainly dominated by chemisorption process. The postsorption characterization results suggested that Mg-induced precipitation was likely the main P adsorption mechanism by ADBC. Moreover, the spent biochar was re-utilized as an efficient phosphate fertilizer for improving wheat seed germination and growth. Provided a sustainable and eco-friendly strategy for sludge treatment and phosphate recovery in wastewater treatment plants (WWTPs) and potential agronomic application.

Acknowledgments

The authors thank the supporters of this project and the referees for their constructive comments.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/26395940.2023.2287237

Additional information

Funding

The work was supported by the China Postdoctoral Science Foundation [2021M701512]; Natural Science Foundation of Jiangsu Province [BK2020201001]; Jiangxi Postdoctoral Preferred Funding Project [2020KY36]; Open Research Fund of Changjiang Survey Planning Design and Research Co., Ltd. [CX2020K09]; Zhenjiang Science & Technology Program [SS2021002].