Remediation of cadmium and lead contaminated soils using Fe-OM based materials

• Published in: Chemosphere (Oxford) 2022-11, Vol.307, p.135853-135853, Article 135853
• Main Authors: Liu, Qianjun, Luo, Jiayi, Tang, Jiepeng, Chen, Zhiliang, Chen, Zhaowei, Lin, Qintie
• Format: Article
• Language: English
• Subjects: Acid rain; Heavy metal; Immobility; Iron oxide; Lignin
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2022.135853

Iron oxide-lignin composites (GLS) were prepared based on the significant role of Fe-OM in the environmental behaviour of heavy metals and lignin binding with iron oxide preferentially in soil. GLS was applied in Cd/Pb immobilization and the stability under acid rain was investigated. The results show that the iron oxide appeared weakly crystalline or amorphous similar to 2-line ferrihydrite after the addition of lignin. Agglomerates of nanoparticles with higher adsorption capacity were observed for GLS. The mobility factor (MF) of Cd/Pb in the soil decreased rapidly after adding GLS. At the 3% dosage, the MF of Cd and Pb in the soil was decreased by 58.94% and 78.15% respectively, which was approximately 5 times that of goethite (GE). The mobile and exchangeable Cd/Pb were converted to organic, amorphous Fe oxide-bound and residue fractions. Under acid rain conditions, MF continues to decline for the GLS group, increasing the organic and amorphous Fe oxide-bound fractions, while for control group (CK) and GE, the trend was the opposite. Lignin could inhibit iron oxide dissolution and stabilize the combination of Cd/Pb and iron oxides in soil. The better stability performance of GLS for Cd/Pb may be related to the higher adsorption capacity and microstructural difference after iron oxide combined with lignin. [Display omitted] •Iron oxide-lignin composites (GLS) show a higher adsorption capacity than goethite.•The mobility of Cd/Pb was decreased significantly after GLS application.•The stability of iron oxide was enhanced after combining with lignin.•GLS application consistently reduces the Cd/Pb leaching under acid rain conditions.