Effects of Ionic Strength, Temperature and pH on Enrichment of Th(Ⅳ) in Aqueous Solution by Nanoscale Zero-valent Iron

Nanoscale zero-valent iron (nZVI) was synthesized in aqueous solutions by reduction method, and was used to enrich Th(Ⅳ) from aqueous solutions. The effects of pH, ionic strength, contact time, temperature and ratio of solid to solution on the enrichment of Th(Ⅳ) were investigated. The results show that nZVI has very good enrichment efficiency on Th(Ⅳ), and pH and ionic strength have obvious effect on the enrichment process. The distribution coefficient increases with pH and decreases with ionic strength at pH≤4.5. The distribution coefficient doesn’t change with the increase of pH and ionic strength at pH>4.5. The distribution coefficient increases with temperature which indicates that increasing temperature is advantageous to the enrichment of Th(Ⅳ) by nZVI.