Competitive Adsorption of Cr(III) and Cu(II) on Electron Beam-Irradiated Sheep Wool from Binary Solutions Can be Controlled by the Absorbed Dose.

Abstract

Sheep wool irradiated by an electron beam was tested for adsorption of Cr(III) and Cu(II) from binary solutions within the same concentration of each cation from 15 to 35 mmol·dm–3. The wool sorptivity examination was aimed at searching the effect of the dose absorbed by wool on simultaneous sorption of these cations due to surface and bulk changes. The partners affected each other under these conditions. In the whole concentration range, the sorptivity of nonirradiated wool (0 kGy) for Cu(II) fluctuated within the range of 14.5–20.7 mg·g–1, while sorptivity for Cr(III) ranged from 14.8 to 7.5 mg·g–1. However, sorptivity for Cu(II) was always superior to Cr(III). At a 24 kGy dose, the wool sorptivity for both cations decreased approximately by half and tended to converge, whereby at 20 mmol·dm–3, a slight predominance for Cr(III) was already observed. However, the sorptivity of 100 kGy dosed wool acquired a clear predominance for Cr(III) over Cu(II) in the entire concentration range, showing some leveling around 14.5 mg·g–1. Sorptivity for Cu(II) was suppressed and increased nonlinearly with concentrations from 1.7 to 10.2 mg·g–1. It was concluded that optimally dosed wool could provide a special adsorbent suitable to control preferential sorption of some cations from binary solutions.