Effectiveness of chelating agent–assisted Fenton-like processes on remediation of glucocorticoid-contaminated soil using chemical and biological assessment: performance comparison of CaO2 and H2O2

Abstract

Glucocorticoids (GCs) have drawn great concern due to widespread contamination in the environment and application in treating COVID-19. Most studies on GC removal mainly focused on aquatic environment, while GC behaviors in soil were less mentioned. In this study, degradation of three selected GCs in soil has been investigated using citric acid (CA)-modified Fenton-like processes (H 2 O 2 /Fe(III)/CA and CaO 2 /Fe(III)/CA treatments). The results showed that GCs in soil can be removed by modified Fenton-like processes (removal efficiency gt; 70% for 24 h). CaO 2 /Fe(III)/CA was more efficient than H 2 O 2 /Fe(III)/ CA at low oxidant dosage (< 0.28-0.69 mmol/g) for long treatment time (> 4 h). Besides the chemical assessment with GC removal, effects of Fenton-like processes were also evaluated by biological assessments with bacteria and plants. CaO 2 /Fe(III)/ CA was less harmful to the richness and diversity of microorganisms in soil compared to H 2 O 2 /Fe(III)/CA. Weaker phytotoxic effects were observed on GC-contaminated soil treated by CaO 2 /Fe(III)/CA than H 2 O 2 /Fe(III)/CA. This study, therefore, recommends CaO 2 -based treatments to remediate GC-contaminated soils. Keywords Glucocorticoid degradation . Fenton-like processes . CaO 2 oxidation . Soil remediation . Microbial communities . Phytotoxic effects Highlights • H 2 O 2 -and CaO 2 -based oxidation can effectively remove GCs from soils. • CaO 2 -based oxidation was more efficient than H 2 O 2 at low oxidant dosage. • CaO 2 -based oxidation was less harmful to soil microorganisms than H 2 O 2 . • H 2 O 2 -based oxidation showed stronger phytotoxic effect than CaO 2 .