Chemical Fractionations of Lead and Zinc in the Contaminated Soil Amended with the Blended Biochar/Apatite

• Published in: Molecules (Basel, Switzerland) Vol. 27; no. 22; p. 8044
• Main Authors: Vuong, Truong Xuan, Stephen, Joseph, Minh, Tu Binh, Nguyen, Thu Thuy Thi, Duong, Tuan Hung, Pham, Dung Thuy Nguyen
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 19.11.2022; MDPI
• Subjects: Agricultural land; Agricultural pollution; Apatite; Apatites; Arachis; bioavailability; biochar properties; Biomass; Charcoal; Chemical Fractionation; Computer software industry; Contamination; Electrical conductivity; Electrical resistivity; Extraction procedures; Fractions; heavy metal remediation; Heavy metals; Inductively coupled plasma mass spectrometry; Land pollution; Lead; Lead - analysis; Manganese; Mass spectrometry; Mass spectroscopy; Metal concentrations; Metals; Metals, Heavy - chemistry; Mineral industry; Mining industry; Organic carbon; Ratios; Sediment pollution; Soil - chemistry; Soil acidity; Soil amendment; Soil contamination; Soil investigations; Soil pH; Soil Pollutants - analysis; Soil pollution; Soil remediation; Zinc; Zinc - analysis; Vietnam; Australia; United States; China; soil amendment; biochar properties; heavy metal remediation; bioavailability; soil remediation
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules27228044

Heavy metal contamination in agricultural land is an alarming issue in Vietnam. It is necessary to develop suitable remediation methods for environmental and farming purposes. The present study investigated the effectiveness of using peanut shell-derived biochar to remediate the two heavy metals Zn and Pb in laboratory soil assays following Tessier’s sequential extraction procedure. The concentration of heavy metals was analyzed using Inductively coupled plasma mass spectrometry (ICP-MS). This study also compared the effectiveness of the blend of biochar and apatite applied and the mere biochar amendment on the chemical fractions of Pb and Zn in the contaminated agricultural soil. Results have shown that the investigated soil was extremely polluted by Pb (3047.8 mg kg−1) and Zn (2034.3 mg kg−1). In addition, the pH, organic carbon, and electrical conductivity values of amended soil samples increased with the increase in the amendment’s ratios. The distribution of heavy metals in soil samples was in the descending order of carbonate fraction (F2) > residue fraction (F5) > exchangeable fraction (F1) > Fe/Mn oxide fraction (F3) > organic fraction (F4) for Pb and F5 ≈ F2 > F1 > F3 > F4 for Zn. The peanut shell-derived biochar produced at 400 °C and 600 °C amended at a 10% ratio (PB4:10 and PB6:10) could significantly reduce the exchangeable fraction Zn from 424.82 mg kg−1 to 277.69 mg kg−1 and 302.89 mg kg−1, respectively, and Pb from 495.77 mg kg−1 to 234.55 mg kg−1 and 275.15 mg kg−1, respectively, and immobilize them in soil. Amending the biochar and apatite combination increased the soil pH, then produced a highly negative charge on the soil surface and facilitated Pb and Zn adsorption. This study shows that the amendment of biochar and biochar blended with apatite could stabilize Pb and Zn fractions, indicating the potential of these amendments to remediate Pb and Zn in contaminated soil.