Insight into UV-LED/PS/Fe(â
¢) and UV-LED/PMS/Fe(â
¢) for p-arsanilic acid degradation and simultaneous arsenate immobilization.
Water Res
; 223: 118989, 2022 Sep 01.
Article
en En
| MEDLINE
| ID: mdl-35998556
ABSTRACT
As a feed additive, p-arsanilic acid (p-ASA) is hardly metabolized in animal bodies and is excreted chemically unchanged via feces and urine, which can be transformed into more toxic inorganic arsenic species and other organic by-products upon degradation in the aquatic environment. In this study, UV-LED/persulfate (PS)/Fe(â
¢) and UV-LED/peroxymonosulfate (PMS)/Fe(â
¢) processes were developed to remove p-ASA and immobilize the formed inorganic arsenic via tuning solution pH. UV-LED/PMS/Fe(â
¢) (90.8%) presented the best performance for p-ASA degradation at pH 3.0, and the p-ASA degradation in these processes both followed the pseudo-first-order kinetics. The âOH played the major role in UV-LED/PS/Fe(â
¢) and UV-LED/PMS/Fe(â
¢) systems. Solution pH greatly affected the p-ASA degradation and the maximum removal can be achieved at pH 3.0 due to the presence of more Fe(OH)(H2O)52+. The dosages of Fe(III) and PMS (PS), SO42- and HCO3- significantly influenced the performance of p-ASA oxidation, while HA, Cl- and NO3- slightly affected the p-ASA degradation. According to quantum chemical calculation, radical addition on the C atom in the C-As bond of p-ASA was corroborated to be the dominant reaction pathway by SO4â- and âOH. Additionally, the reactive sites and reasonable degradation pathways of p-ASA were proposed based on DFT calculation and HPLC/MS analysis. The release of inorganic arsenic in both processes can be effectively immobilized and the toxicity of the reaction solution dramatically reduced by adjusting solution pH to 6.0. UV-LED/PMS/Fe(â
¢) process was found to be more cost-effective than UV-LED/PS/Fe(â
¢) process at the low oxidant dosages.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Arsénico
/
Contaminantes Químicos del Agua
Límite:
Animals
Idioma:
En
Revista:
Water Res
Año:
2022
Tipo del documento:
Article
País de afiliación:
China