Study of sorption of chromium(VI) ions by fibre anion-exchangers

Sorption of chromium(VI) ions by fibre anion-exchangers containing pyridine, imidazole, hydrazidine, and aliphatic amino groups was investigated. It was shown that the basicity of the sorbents has almost no effect on their selectivity in absorption of chromium ions from solutions. The fibres with pyridine and imidazole groups have higher distribution coefficients, and their capacity for chromium ions is 130 and 120 mg/g, respectively. Sorption of chromium(VI) ions by the fibre sorbent with pyridine groups also corresponds to a mired diffusion mechanism in dynamic conditions and the internal diffusion coefficient is 3.10(-10) cm(2)/sec. Fibres with low-basicity pyridine groups are resistant to the oxidizing effect of chromium(VI) ions and their exchange capacity is preserved in repeated sorption-desorption cycles. Conversion of pyridine groups to the form of a strong base decreases the chemical stability of the sorbent in absorption of chromium(VI) ions from solutions.