| Autor: |
Alam R; Department of Chemistry, Physics, and Atmospheric Sciences, Jackson State University, Jackson, Mississippi 39217, United States., Roy SC; Department of Chemistry, Physics, and Atmospheric Sciences, Jackson State University, Jackson, Mississippi 39217, United States., Islam T; Department of Chemistry, Physics, and Atmospheric Sciences, Jackson State University, Jackson, Mississippi 39217, United States., Feng R; Canadian Light Source, Saskatoon, Saskatchewan S7N 2 V3, Canada., Zhu X; Department of Civil Engineering, Jackson State University, Jackson, Mississippi 39217, United States., Donley CL; Department of Chemistry, and Chapel Hill Analytical and Nanofabrication Laboratory (CHANL), University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States., Islam SM; Department of Chemistry, Physics, and Atmospheric Sciences, Jackson State University, Jackson, Mississippi 39217, United States. |
| Abstrakt: |
Effective removal of chemically toxic selenium oxoanions at high-capacity and trace levels from contaminated water remains a challenge in current scientific pursuits. Here, we report the functionalization of the MgAl layered double hydroxide with molybdenum-oxysulfide (MoO 2 S 2 ) anion, referred to as LDH-MoO 2 S 2 , and its potential to sequester Se VI O 4 2- and Se IV O 3 2- from aqueous solution. LDH-MoO 2 S 2 nanosheets were synthesized by an ion exchange method in solution. Synchrotron X-ray pair distribution function (PDF) and extended X-ray absorption fine structure (EXAFS) revealed an unexpected transformation of the MoO 2 S 2 2- to Mo 2 O 2 S 6 2- like species during the intercalation process. LDH-MoO 2 S 2 is remarkably efficient in removing SeO 4 2- and SeO 3 2- ions from the ppm to trace level (≤10 ppb), with distribution constant ( K d ) ranging from 10 4 to 10 5 mL/g. This material showed exceptionally high sorption capacities of 237 and 358 mg/g for SeO 4 2- and SeO 3 2- , respectively. Furthermore, LDH-MoO 2 S 2 demonstrates substantial affinity and efficiency to remove SeO 3 2- /SeO 4 2- even in the presence of competitive ions from contaminated water. Hence, the removal of selenium (VI/IV) oxoanions collectively occurs through reductive precipitation and ion exchange mechanisms. This work provides significant insights into the chemical structure of the MoO 2 S 2 anion into LDH and emphasizes its exceptional potential for high-capacity selenium removal and positioning it as a premier sorbent for selenium oxoanions. |
