Peg-salt-h <sub> 2 </ Sub> O Aqueous Two-phase System In Titanium, Zirconium Enrichment Of Trace

Aqueous two-phase system is a new kind of extraction separation system quickly developed in recent years. Aqueous two-phase extraction is a technique which is used special extraction method and based the principle that soluble polymer solution can separate two phase in the presence of inorganic salt and matter will selective distribute in two phase.The separation and concentration of two elements in the same group(IVB)-Titanium(IV) and Zirconium(IV) using polyethylene glycol 2000(PEG)-salt-water aqueous two-phase system were investigated.(1) The conditions of PEG aqueous two-phase system separating into two phase and the factors affect extraction such as inorganic salt, pH, and the degree of polymerization of PEG were analyzed.(2) The distribution behavior of Ti(IV) and Zr(IV) in aqueous two-phase system has been investigated in the presence of Arsenazo III as the extractant. The factors affect extractions such as pH, the concentration of extractant and salt, ionic strength, etc. were analyzed through many experiments. Ti(IV) and Zr(IV) were separated in mixing solution.(3) The composition of Zr-ASAIII complex in PEG phase was determinated by mole ratio method and continuous variation method. Zr:ASAlII = l:2 in 9mol/L HC1. The relationship of Ti(IV) and Arsenazo III in PEG phase was analyzed through their absorption spectrum. The affection caused by different surface-active agents to the extractability was investigated. Mechanism of extraction in PEG aqueous two-phase system was studied on the basis of the results and combined theory. It was believed that metal extraction in Aqueous two-phase system is the result of complexation reaction, electrostatic effect and hydrogen bonding and hydrophobic bonding.(4) In the ionic determination, the effective spectrophotometry to Ti(IV) and Zr(IV) without interference were found. Ti(IV)and Zr(IV) were determinated by spectrophotometry with diantipyrylmethane(DAM)and ArsenazoIII(ASAIII) as the chromogenic agents. The stable time of complexes and the fators that affectdetermination were studied. The optimized conditions were decided through manyexperiments that used the characteristic factor of aqueous two-phase system to determinate metal ion in upper phase without back extraction.The author decided optimized condition that is 1.0ml0.1% ArsenazoIIIsolution, 15ml 30%PEG solution, pH=0.7, 6g ammoniumi 30ml total volume and used PEG aqueous two-phase system have succeeded in the quantitation separation of Ti(IV) and Zr(IV)mixing solution : 98.4% Zr(IV) enrichments in PEG phase and 96% Ti(IV) enrichments in under phase. The method has high extractability, simple operation, low price, without poison advantages compared with traditional methods.