Activation of persulfate by vanadium oxide modified carbon nanotube for 17f3-estradiol degradation in soil: Mechanism, application and ecotoxicity assessment

Steroid hormones in the environment have attracted public attention because of their high endocrine-disrupting activ-ity even at rather low exposure level. Excessive hormones in the soil from the pollutant discharge of intensive farming would pose a potential threat to the ecology and the human health. Vanadium oxide modified carbon nanotube (VOX- CNT) was synthesized and applied as persulfate (PDS) activator to reduce17f3-estrogen (17f3 -E2) in soil. 86.06 % 17f3 -E2 could be degraded within 12 h. Process of materials exchange during oxidation was interfered by soil, resulting in insufficient degradation of 17f3 -E2, but the active species involved in 17f3 -E2 degradation would also be enriched by it. 17f3 -E2 was adsorbed on the VOX-CNT surface and directly degraded mainly by the active species generated on the cat-alyst surface, and center dot OH dominated the degradation of 17f3 -E2 in VOX-CNT/PDS system. C_O, defective sites and vana-dium oxides on the surface of VOX-CNT contributed to the generation of activate species. Oxidizer dosage, catalyst dosage, water-soil ratio and soil properties would affect the degradation of 17f3 -E2. The ecotoxicological impact on soil caused by VOX-CNT/PDS was acceptable, and would be weakened with time. Additionally, a rapid decrease in the concentration of 17f3 -E2 and the promotion of maize growth were observed with VOX-CNT/PDS in situ pilot -scale remediation. Those results reveal that VOX-CNT/PDS is a potential technology to remove excessive steroid hor-mone from soil around large-scale livestock and poultry farms.