Biopolymer-Biochar matrix for long-term stabilization of arsenic in soil: Performance, mechanisms, and the effect of cationic heavy metals

• Published in: Biomass conversion and biorefinery 2024, Vol.14 (21), p.27503-27517
• Main Authors: Kim, Dong-Su, Moradi, Hiresh, Chang, Yoon-Young, Yang, Jae-Kyu
• Format: Article
• Language: English
• Subjects: Alkalinity; Arsenic; Biopolymers; Biotechnology; Cations; Efficiency; Energy; Heavy metals; Iron oxides; Magnetic properties; Original Article; Performance evaluation; Rainfall; Red mud; Renewable and Green Energy; Soil contamination; Soil erosion; Soil investigations; Soil pollution; Soil remediation; Soil testing; Stabilization
• ISSN: 2190-6815; 2190-6823
• DOI: 10.1007/s13399-022-03531-9

Powder biochar has been reported as an efficient stabilizer for heavy metal contaminated soils. However, infrequent studies addressed its long-term performance in real multi-metal polluted soil. This study aimed to investigate the long-term performance of iron oxide-loaded biochar (IOBC) in stabilization of arsenic and cationic heavy metals in a real multi-contaminated soil. Besides, to overcome the drawbacks of powder-type IOBC, the granular and suspension forms of IOBC were prepared using biopolymers as polymeric binder. The performance of prepared IOBCs was evaluated against red mud (RM) and pristine biochar, as references. Two single extraction tests (TCLP and SPLP) and a sequential extraction test were adopted to evaluate the stabilization efficiency for the soil samples containing 5 w/w % of the prepared IOBCs. It was observed that although stabilizers with high alkalinity (RM and BC) showed negligible or low immobilization of arsenic, the SPLP stabilization efficiency was ≥ 74.9% and the TCLP stabilization efficiency was ≥ 89.1% for arsenic. Furthermore, the biopolymer-biochar suppressed PM 2.5 and PM 10 concentration during mixing. The soil loss in artificial rainfall was more than 400 g/m 2 lower in the soil sample containing IOBC-suspension compared to control sample. The results indicated the high potential of the prepared stabilizers, especially IOBC-suspension, for large-scale remediation of multi-contaminated soils. Highlights Stabilization efficiency was affected by the type of magnetic stabilizer. Performance of IOBC-based stabilizers was superior to the commercial red mud. Wetting properties of PVA significantly prevented dusting of powder stabilizer. Positive synergetic effect of magnetic stabilizer and biopolymers was observed.