| Autor: |
Xiao-Fang Pei, Jun Wan, Kun Zhang, Li-Hua Niu, Qian Du, Chun-Xue Zhang, Xin-Shi Wu, Bo Sun |
| Předmět: |
|
| Zdroj: |
Desalination & Water Treatment; May2018, Vol. 113, p131-147, 17p |
| Abstrakt: |
Fixation of heavy metal cations in plant Sedum spectabile was studied. The key heavy-metal cation fixation species (ions or function groups) and the auxiliary species that promote heavy-metal cation fixation in the plant were investigated. The species involved in the fixation of tested heavy-metal cations (Cd2+, Cu2+, Ni2+, Mn2+ and Zn2+) were first surmised based on changes of the elemental composition in plant’s roots. Their roles in the fixation of heavy metals were assessed and confirmed using simulated precipitation and adsorption of heavy-metal cations under near physiological conditions (20–35°C, pH 6–7.5). CO3 2- and PO4 3- were the key Cd2+- fixing species, and Fe3+ ions played an auxiliary role in the precipitation of Cd2+ ions. PO4 3--containing species were also key species for the fixation of Cu2+, Mn2+, Ni2+ and Zn2+, and Ca2+ and HCO3- ions aided the precipitation of these cations. In the presence of a complexing agent, the pH of the solution was a key factor that can severely affect the removal of heavy metal cations. At pH 7–7.5 and in the presence of citrate, the removal percentage of Cu2+ from the solution can be as high as 99.0%, with residual concentration as low as 0.05 mg/L. Based on the obtained results, a biomimetic composite made of sodium alginate and calcium- containing phosphate was prepared via co-precipitation in the presence of Mg2+ and HCO3- ions under near-physiological conditions. The composite was excellent for removing low concentrations of heavy-metal cations under near-neutral conditions. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
