氯化钠-α-亚硝基-β-萘酚-酚酞体系分离富集钴(Ⅱ)

摘要

A novel separation and enrichment method of cobalt (Ⅱ) using microcrystalline phenolphthalein as adsorbent was established. The effect of addition amount of α-nitroso-β-naphthol (HL) and phenolphthalein, the type and dosage of salt, and acidity on the enrichment yield of Coz+ was investigated. The optimal separation and enrichment conditions of cobalt (Ⅱ) were obtained. The enrichment mechanism of Co2+ was discussed. The results showed that Co2+ could react with HL to form reddish brown chelate precipitate (CoL3) which was quantitatively adsorbed on microcrystalline phenolphthalein under the following conditions: at pH 5. 0; in the presence of 1. 0 g of NaCl; the dosages of 2. 0g/L HL and 5 ％ phenolphthalein solution were 0. 60 mL and 0. 10 mL, respectively. Consequently,Co2+ could be quantitatively enriched, while Zn2+, Mn2+ , Al3+ and Cd2+ were not adsorbed under these conditions, realizing the quantitative separation of Co2+ from these ions. This method had been applied to the quantitative enrichment, separation and determination of micro Co2 + in synthetic water samples. The enrichment yield was 99. 8 ％-108. 6 ％.%建立了一种以微晶酚酞作吸附剂分离富集痕量Co(Ⅱ)的新方法.探讨了α-亚硝基-β-萘酚(HL)及酚酞用量、盐的种类及用量、酸度等因素对Co2+富集率的影响,得到了分离富集钴(Ⅱ)的最佳条件,讨论了Co2+的富集机理.结果表明:控制pH值为5.0,在1.0 g NaCl存在下,当2.0 g/L 亚α-亚硝基-β-萘酚溶液用量和5%酚酞溶液用量分别为0.60 mL和0.10 mL时,Co2+与α-亚硝基-β-萘酚(HL)反应生成的红棕色螯合物沉淀CoL3被定量吸附在微晶酚酞上,Co2+被定量富集,而Zn2+,Mn2+,Al3+,Cd2+在此条件下不被吸附,从而实现了Co2+与这些离子的定量分离.方法用于合成水样中微量Co2+的定量富集分离测定,富集率为99.8%～108.6%.