Browsing by Author "Cookson, PG"

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    Metal ion binding properties of novel wool powders
    (Wiley-Blackwell, 2010-02-05) Naik, R; Wen, G; Dharmaprakash, MS; Hureau, S; Uedono, A; Wang, XG; Liu, XG; Cookson, PG; Smith, SV
    Wool fibres have shown potential for the removal and recovery of toxic chemical and metal ions; however, their slow kinetics of binding has limited their widespread application. In this study three wool powders have been prepared from chopped wool fibre using various milling operations. Brunauer, Emmett, Teller analysis (BET) showed negligible change in surface area and Positron annihilation lifetime spectroscopy indicated no change in nanoporosity of the powders on processing. Binding of the transition metal ions, Co2+, Cu2+, and Cd2+ was investigated over the pH range 3-9 at ambient temperature (23°C) using their respective radioisotopes (i.e. 57Co, 64Cu, or 109Cd). The optimum pH for binding of Cu2+ and Cd2+ was in the range 6-8, while Co2+ absorption peak was sharp at pH 8. The rate of uptake of Cu2+ for each of the wool powder was dramatically faster (42 fold) than that of the wool fibre. In comparison with commercial cation exchange resins, the wool powders showed significantly higher (two to nine fold) metal ion loading capacity. Selective binding of the metal ions could be enhanced by varying pH and/or incubation times. The use of radioisotopes to monitor the metal ion binding allowed the development of a highly sensitive and rapid high-throughput analysis method for assessing wool powder binding properties. The ability to produce large quantities of wool powders and their ease of handling indicate that they have potential for application in separation and recovery of metal ions from industrial effluents and environmental waterways. © 2010, Wiley-Blackwell. The definitive version is available at www3.interscience.wiley.com
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    Wool powders used as sorbents to remove Co2+ ions from aqueous solution
    (Elsevier, 2010-01-25) Wen, G; Naik, R; Cookson, PG; Smith, SV; Liu, XG; Wang, XG
    The Co2+ sorption of two wool powders was investigated using its radioisotope 57Co (T1/2 = 271.8 days and γ = 122.1 and 136.5 keV) as a tracer. The effects of the type of buffer, the pH value, the contact time and the initial concentration of Co2+ on the sorption behaviour of wool powders were studied. The Co2+ releasing ability of wool powders and the re-use of wool powders to sorb Co2+ were also examined. The optimum sorption of Co2+ by the powders occurred at pH 8 in phosphate buffer and pH 10 in ammonium sulphate buffer. Fourier-transform infrared spectroscopy (FTIR) was used to study the changes in chemical structure of the wool after exposure to both buffer solutions. Compared to the untreated wool fibre, the fine wool powders showed rapid sorption rates and high sorption capacities for Co2+. Co2+ ions were recovered after exposing the Co2+ loaded wool to HCl (0.1 M) and buffer at pH 3 (glycine/sodium chloride). After releasing Co2+ ions from wool powders, the efficiency of wool powders re-used to sorb Co2+ was 80% of that of the fresh wool powders. It is concluded from this study that wool powder can be used as an efficient sorbent to remove and release Co2+ from solution. © 2010, Elsevier Ltd.