Stabilization Mechanism of Highly Toxic Hexavalent Chromium during Carbothermal Reactions in Lettuce
Year: 2025
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide As a remediation plant for remediating cadmium-contaminated soil, highly toxic Cr(VI) is enriched in lettuce, making the rational treatment of this biomass a challenge to be solved. In this work, CaO, which is cheap and available, was used as a stabilizer for the pyrolysis of polluted lettuce. Results revealed that the Cr(VI):Cr ratio in lettuce-derived biochar obtained at 800 °C decreased by 93.6% in comparison to that at 400 °C due to the immobilization effects. Spearman correlation analysis also revealed that Cr(VI) was negatively correlated with CaO dosage ( R 2 = −0.81, p ≤ 0.01) and pyrolysis temperature ( R 2 = −0.86, p ≤ 0.01). Furthermore, Cr(VI) was reduced to Cr(V) and Cr(III) in the presence of CaO during the pyrolysis. XRD analysis and SEM-EDS analysis further confirmed that the Cr(V) compound refers to Ca 5 (CrO 4 ) 3 OH as well as Ca 5 (CrO 4 ) 3 Cl. The intensity of the peak of the aromatic ring and heteroaromatic compounds on the surface of biochar presents a significant increase when the CaO dosage was higher than 10%. Furthermore, these redox-active functional groups act as electron donors in the reduction of Cr(VI). Meanwhile, Cr(VI) was partially converted preferentially to Ca 2 CrO 4 Cl in the copresence of CaO and Fe 2 O 3, resulting in the immobilization of Cr(VI). This study clarifies the influence of CaO dosage and temperature on the Cr(VI) transformation and characteristic of biochar and provides a new strategy for Cr(VI) remediation of the Cr-contaminated biomass.
Source: ACS Omega
Authors: Qiong Wang, Hugang Li
Language: English
Subfield: Health, Toxicology and Mutagenesis
Field: Environmental Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,935
Awards: G1007352147, G6779847096, G8639945470
OpenAlex ID: W4411151280