Interactive effects of rice straw biochar and Γ-Al2O3 on immobilization of Zn

Ping Wu, Peixin Cui, Marcelo E. Alves, Willie J.G.M. Peijnenburg, Cun Liu, Dongmei Zhou, Hailong Wang, Yong Sik Ok, Yujun Wang

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)


Biochar system technology has been proved as a sustainable remediation method for metal contaminated soils. However, little attention has been paid to the interaction between biochar and oxide minerals and their influence on metal immobilization in soils. In this study, batch-type Zn sorption experiments were conducted using the mixture of γ-Al2O3 and rice straw biochar as a model binary geosorbent systems. In addition, advanced spectroscopic technics such as EXAFS, FTIR and XRD were performed to reveal the mechanism. EXAFS spectroscopy revealed that 62% of Zn existed as Zn-Al layered double hydroxide (LDH) on γ-Al2O3 at pH 7.5 (for 2 mM Zn loading) within 24 h, which was 19% in the mixture. The Zn in biochar samples mainly existed as Zn-OM (53%–76%) and Zn2SiO4 (21%–47%), while the proportion of Zn2SiO4 (0–6%) was negligible compared with Zn-Al silicate (26–48%) in the mixtures. The overall findings confirmed that Al released from γ-Al2O3 was sorbed in parallel with Zn on biochar to form Zn-Al silicate, rather than Zn-Al LDH on the γ-Al2O3 surface. These results unveiled the dynamic interactions between amended biochar and soil oxide minerals which can significantly affect the immobilization pathways of metals in contaminated soils.

Original languageEnglish
Pages (from-to)250-257
Number of pages8
JournalJournal of hazardous materials
Publication statusPublished - 2019 Jul 5

Bibliographical note

Funding Information:
We acknowledge the support from the National Natural Science Foundation of China (Project No. 21537002, 41671478 and 41701359), and the Natural Science Foundation of Jiangsu Province, China (Project No. BE2018760). We are grateful to the staff of beamline 14W1 in Shanghai Synchrotron Radiation Facility for enabling the EXAFS experiments.


  • Black carbon
  • Chemical stabilization
  • Soil remediation
  • Synchrotron
  • Zinc immobilization

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution
  • Health, Toxicology and Mutagenesis


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