Pan, et al (2024) Synergy of carboxymethyl cellulose stabilized nanoscale zero-valent iron and Penicillium oxalicum SL2 to remediate Cr(VI) contaminated site soil. Frontiers.

Nano zero-valent iron (nZVI) has shown promise in soil remediation, particularly for removing the toxic hexavalent chromium (Cr(VI)). However, its tendency to oxidize quickly and its biological toxicity have limited its effectiveness and practicality. A recent study has tackled these challenges by developing a series of modified nZVI materials and integrating them with the Cr(VI)-resistant fungus, Penicillium oxalicum SL2, to improve real-site chromium pollution remediation.

The study highlighted the enhanced performance of nZVI when modified with carboxymethyl cellulose (CMC). This modification significantly increased the adsorption capacity of nZVI for Cr(VI) by 19.3%, reaching 87.4 mg/L compared to the unmodified nZVI’s 73.25 mg/L. The performance of CMC-modified nZVI also surpassed other materials like biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More and bentonite-modified nZVI.

Detailed characterization confirmed the successful synthesis of the nano composite material. The oxidative stress analysis revealed that CMC not only acts as a free radical scavenger but also as a protective layer, providing unique detoxification benefits for the fungus SL2.

In field experiments, a low dosage (0.4% w/w) of the composite material, nZVI/CMC@SL2, achieved remarkable results, reducing over 99.5% of TCLP-Cr(VI) and transforming 18% of unstable Cr into stable forms. Moreover, this composite facilitated SL2 colonization in contaminated soils and enhanced the microbial community structure, promoting the proliferation of chromium-removing microorganisms.

This innovative nZVI/CMC@SL2 system offers a cost-effective and efficient solution for Cr(VI) reduction, marking a significant advancement in the field of soil remediation and providing valuable insights for future applications in contaminated site management.