利用二氧化钛生产过程中产生的富含硫酸亚铁的副产物在碱性条件下制备聚合羟基磷酸铁(PHFP),用于固定土壤中的铅和镉.利用傅里叶变换红外光谱和X射线衍射分析所制备聚合羟基磷酸铁的结构特征;采用改进的Tessier连续提取法并模拟酸雨淋溶以评价土壤中镉和铅的固定效果.结果表明,羟基磷酸铁是一种含有复杂OH—Fe—P结构的多聚物,主要由Fe6(OH)5(H2O)4(PO4)4(H2O)2和Fe25(PO4)14(OH)24组成.当其以4%的比例加入土壤中,土壤中DTPA提取态镉和铅的去除率分别达33%和45%,水溶态镉和铅的去除率分别降低了56%和58%.镉和铅的固定是由于水溶态、交换态和碳酸盐结合态转化为铁锰氧化物结合态、有机结合态和残渣态.模拟酸雨淋溶下,采用羟基磷酸铁修复后土壤中镉和铅的释放量较修复前分别下降了53%和52%.结果表明该羟基磷酸铁具有修复镉和铅污染土壤的应用潜力.
A polymeric hydroxyl ferric phosphate (PHFP) was prepared by using a byproduct of titanium dioxide containing ferrous sulfate and phosphates under alkaline condition. The PHFP was used to immobilize lead (Pb) and cadmium (Cd) in soils. Fourier transform infrared spectra, X-ray diffraction were applied to revealing the characteristics of PHFP, and the modified Tessier sequential extraction and column leaching experiment with simulated acid rain were used to assess the effectiveness of immobilization of Cd and Pb in soils by PHFP. The results showed that PHFP was indeed a polymer with complicated OH—Fe—P structure and consisted of Fe6(OH)5(H2O)4(PO4)4(H2O)2 and Fe25(PO4)14(OH)24. Moreover, the removal rates of DTPA-extractable Cd and Pb in soils reached up to 33% and 45%, and the water-soluble Cd and Pb decreased by 56% and 58%, respectively, when PHFP was added in soils at 4% dosage. In addition, the immobilization of Cd and Pb contributed to transforming water soluble, exchangeable and carbonate-bonded fractions to Fe and Mn oxides-bonded, organic-bonded and residual fractions. Under leaching with simulated acid rain, Cd and Pb release amount in PHFP amended soil declined by 53% and 52%, respectively, as compared with non-treated soil. The result implied that PHFP had a potential application for the remediation of Cd- and Pb-contaminated soils.
参考文献
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%