Fixed-bed operation for manganese removal from water using chitosan/bentonite/MnO composite beads

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), N adsorption-desorption and X-ray photoelectron spectroscopy (XPS) techniques, and moreover the point of zero charge (pH) 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 (t), bed exhaustion time (t), bed capacity (q) 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 (q), 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.

The adsorption of phosphate using a magnesia–pullulan composite: kinetics, equilibrium, and column tests

“…This can be ascribed to the higher driving force of mass transfer caused by the greater phosphate concentration gradient between the solution and MgOP surface. These findings also indicate that the fixed-bed adsorption process depends on the phosphate concentration (Muliwa et al 2018;Nur et al 2014;Shi et al 2018). However, the breakthrough time for phosphate adsorption decreases from 11.2 observed for an influent phosphate concentration of 1 mg/L to 0.65 h observed for an influent phosphate concentration of 20 mg/L.…”

Preparation and Characterization of Sodium Alginate Based Composite Beads for Manganese Removal

“…Therefore, the objective of this work is to examine the performance of the sodium alginate (SA) beads and the comparison with the PCC, BMnO and PCC-BMnO composite beads in removing manganese from aqueous solutions will be observed. The preparation of BMnO was adopted and modified from the literature whereas PCC was produced from carbide lime using sucrose ionic solution acquired from in-house production in Mineral Research Centre, Department of Mineral and Geoscience Malaysia [8].…”

Preparation, characterization serpentine-loaded hydroxyapatite and its simultaneous removal performance for fluoride, iron and manganese

“…7,8 There are many studies on the treatment of groundwater containing uorine at home and abroad, and many scholars have conducted studies on groundwater containing excess iron and manganese. [9][10][11] However, there are few studies on simultaneous removal when these three ions coexist, so it is necessary to combine groundwater uoride removal with the removal of iron and manganese. 12 Compared with other contaminant treatment methods in groundwater, adsorption has the advantages of low cost and environmental friendliness and has become a popular method for uoride and manganese removal.…”