铬天青S-正丙醇-氯化钠体系萃取分离铝(Ⅲ)

摘要

研究了铬天青S-正丙醇-氯化钠体系析相萃取分离和富集铝的行为及与一些金属离子分离的条件,结果表明,氯化钠能使正丙醇的水溶液分成两相,在分相过程中,Al3+和铬天青S(CAS)生成的Al(CAS)2与质子化正丙醇C3H7OH2+形成的缔合物[Al (CAS)2-] [C3H7OH2+]能被正丙醇相完全萃取,当溶液pH值为4,正丙醇、铬天青S和氯化钠的浓度分别为30％(V/V)、5.0×10-4 mol/L和0.17 g/mL时,Al3+的萃取率达到97.8％以上,而Ru3+、Ir4+、Pd2+、Fe2+、Ni2+、Co2+、Cr3+、Mg2+、V5+和Ag+基本不被萃取,实现了Al3+与上述金属离子的分离.对合成水样和镍铬铝合金中铝的分离和测定,结果满意.该方法在微量铝的分离和富集分析中有一定的实用价值.%The extraction separation and enrichment behaviors of aluminum(Ⅲ) in chromazurine S-nor-mal propyl alcohol-sodium chloride system as well as the separation conditions of some metal ions were studied. The results showed that, sodium chloride could separate the normal propyl alcohol aqueous solution into two phases. The Al(CAS)2 -formed from Al3+ and S(CAS) could react with protonized normal propyl alcohol C3H7OH2+ to form complex [A1(CAS)2 -][C3H7OH2+], which could be fully extracted by normal propyl alcohol phase during the phase separation process. When the pH of solution was 4, and the concentration of normal propyl alcohol, chromazurine S and sodium chloride was 30 % (V/V), 5. 0×10-4 mol/L and 0. 17 g/mL, respectively, the extraction rate of Al3+ was higher than 97. 8%. At the same time, Ru3+ , Ir4+ , Pd2+ , Fe2+ , Ni2+ , Co2+ , Cr3+ , Mg2+ , V5+ and Ag+ could not be extracted, realizing the separation of Al3+ from these metal ions. The aluminum in synthetic water samples and Ni-Cr-Al alloy samples was separated,and determined and the results were satisfactory. The proposed method had certain practical value in the separation and enrichment analysis of trace aluminum.