Abstract
In the present study, a new composite adsorbent, chitosan/bentonite/manganese oxide (CBMnO) beads, cross-linked with tetraethyl-ortho-silicate (TEOS) was applied in a fixed-bed column for the removal of Mn (II) from water. The adsorbent was
characterised by scanning electron microscopy (SEM), Fourier transform infra-red (FT-IR), N2 adsorption-desorption and X-ray
photoelectron spectroscopy (XPS) techniques, and moreover the point of zero charge (pHpzc) was determined. The extend of Mn
(II) breakthrough behaviour was investigated by varying bed mass, flow rate and influent concentration, and by using real
environmental water samples. The dynamics of the column showed great dependency of breakthrough curves on the process conditions. The breakthrough time (tb), bed exhaustion time (ts), bed capacity (qe) and the overall bed efficiency (R%) increased with an increase in bed mass, but decreased with the increase in both influent flow rate and concentration. Non-linear regression suggested that the Thomas model effectively described the breakthrough curves while large-scale column performance could be estimated by the bed depth service time (BDST) model. Experiments with environmental water revealed that coexisting ions had little impact on Mn (II) removal, and it was possible to achieve 6.0 mg/g breakthrough capacity (qb), 4.0 L total treated water and
651 bed volumes processed with an initial concentration of 38.5 mg/L and 5.0 g bed mass. The exhausted bed could be regenerated with 0.001 M nitric acid solution within 1 h, and the sorbent could be reused twice without any significant loss of capacity. The findings advocate that CBMnO composite beads can provide an efficient scavenging pathway for Mn (II) in polluted water.
characterised by scanning electron microscopy (SEM), Fourier transform infra-red (FT-IR), N2 adsorption-desorption and X-ray
photoelectron spectroscopy (XPS) techniques, and moreover the point of zero charge (pHpzc) was determined. The extend of Mn
(II) breakthrough behaviour was investigated by varying bed mass, flow rate and influent concentration, and by using real
environmental water samples. The dynamics of the column showed great dependency of breakthrough curves on the process conditions. The breakthrough time (tb), bed exhaustion time (ts), bed capacity (qe) and the overall bed efficiency (R%) increased with an increase in bed mass, but decreased with the increase in both influent flow rate and concentration. Non-linear regression suggested that the Thomas model effectively described the breakthrough curves while large-scale column performance could be estimated by the bed depth service time (BDST) model. Experiments with environmental water revealed that coexisting ions had little impact on Mn (II) removal, and it was possible to achieve 6.0 mg/g breakthrough capacity (qb), 4.0 L total treated water and
651 bed volumes processed with an initial concentration of 38.5 mg/L and 5.0 g bed mass. The exhausted bed could be regenerated with 0.001 M nitric acid solution within 1 h, and the sorbent could be reused twice without any significant loss of capacity. The findings advocate that CBMnO composite beads can provide an efficient scavenging pathway for Mn (II) in polluted water.
| Original language | English |
|---|---|
| Pages (from-to) | 18081-18095 |
| Number of pages | 15 |
| Journal | Environmental Science and Pollution Research |
| Volume | 25 |
| DOIs | |
| Publication status | Published - 2018 |