Abstract
Cylindrical bonds representative diagram of alumina-coated MWCNTs.
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▶ Comparing with uncoated-MWCNTs, alumina-coated MWCNTs has higher adsorption capacity toward lead. ▶ In the fixed bed mode, the percentage of lead removal increases by decreasing the flow rate. ▶ The lead removal increases when the bed thickness increases.
Alumina-coated multi-wall carbon nanotubes were synthesized and characterized by scanning electron microscopy, X-ray diffraction, and FTIR. They were used as an adsorbent for the removal of lead ions from aqueous solutions in two modes, batch and fixed bed. In the batch mode, experiments were carried out to investigate the effect of contact time, agitation speed, adsorbent dosage and solution pH on the removal of lead. The coated nanotubes exhibit better removal ability over uncoated. For fixed-bed columns, thickness of the layer and flow rate were investigated. Increasing the thickness and decreasing the flow rate enhanced the removal of lead. The prepared adsorbent displayed the main advantage of separation convenience when a fixed-bed column was used compared to the batch adsorption treatment.