P-enriched hydrochar for soil remediation: Synthesis, characterization, and lead stabilization

Feiyue Li; Andrew R Zimmerman; Yulin Zheng; Yicheng Yang; Jinsheng Huang; Yue Zhang; Xin Hu; Zebin Yu; Jun Huang; Bin Gao

doi:10.1016/j.scitotenv.2021.146983

P-enriched hydrochar for soil remediation: Synthesis, characterization, and lead stabilization

Sci Total Environ. 2021 Aug 20:783:146983. doi: 10.1016/j.scitotenv.2021.146983. Epub 2021 Apr 9.

Authors

Feiyue Li¹, Andrew R Zimmerman², Yulin Zheng³, Yicheng Yang³, Jinsheng Huang³, Yue Zhang³, Xin Hu⁴, Zebin Yu⁵, Jun Huang⁶, Bin Gao⁷

Affiliations

¹ College of Resources and Environment Science, Anhui Science and Technology University, Fengyang 233100, China; Department of Agricultural and Biological Engineering, University of Florida, Gainesville, FL 32611, USA.
² Department of Geological Sciences, University of Florida, Gainesville, FL 32611, USA.
³ Department of Agricultural and Biological Engineering, University of Florida, Gainesville, FL 32611, USA.
⁴ Center of Material Analysis, Nanjing University, Nanjing 210093, China.
⁵ School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China.
⁶ Hualan Design & Consulting Group Co. Ltd., Nanning 530011, China; College of Civil Engineering and Architecture, Guangxi University, Nanning 530004, China.
⁷ Department of Agricultural and Biological Engineering, University of Florida, Gainesville, FL 32611, USA. Electronic address: bg55@ufl.edu.

PMID: 34088139
DOI: 10.1016/j.scitotenv.2021.146983

Abstract

One-step synthesis of multifunctional materials using biomass waste for environmental remediation is a current research hotspot. In this study, a novel P-enriched hydrochar was obtained by co-hydrothermal treatment of biomass (bamboo or hickory) with concentrated H₃PO₄ (biomass: H₃PO₄ = 1:4) at 200 °C for 7 h. The characteristics of the P-enriched hydrochar were determined and its effect on the stabilization of Pb in soils was investigated. Compared to pristine hydrochar, the weight yield of the P-enriched hydrochar was greater (by over 2 times). This was due to the enrichment of P (over 20% by weight), as the C, N, and H weight content was reduced. Moreover, the aromaticity, thermal stability, and surface functionality of P-enriched hydrochar were all higher than that of pristine hydrochar. Addition of the pristine hydrochar to a simulated 1300 mg·kg^-1 Pb-contaminated soil at 3% (w/w) resulted in a 20%-40% reduction in leached Pb only after 4 weeks, compared to the control without hydrochar amendment. However, addition of the P-enriched hydrochar to the spiked Pb-contaminated soil reduced Pb leaching by about 60% after only 1 week and about 90% after 3 weeks. Besides, using a real Pb-contaminated soil (149,000 mg·kg^-1 Pb), P-enriched hydrochar addition at 5% (w/w) resulted in a 100% decrease in Pb leaching in the first week and maintained leached Pb levels at <2 mg L^-1, meeting U.S.-E.P.A. standards. Thus, P-enriched hydrochar stabilized Pb in both simulated and real Pb-contaminated soil quickly and efficiently. Hence, the potential of one-step co-hydrothermal carbonization of biomass with H₃PO₄ to produce a novel and sustainable P-enriched hydrochar with properties suitable for environmental remediation of cationic metals.

Keywords: Engineered hydrochar; Heavy metal stabilization; Soil remediation.