Balarama Krishna M V, Chandrasekaran K, Rao Sarva V, Karunasagar D, Arunachalam J
Department of Atomic Energy, National Center for Compositional Characterization of Materials (CCCM), Bhabha Atomic Research Centre, ECIL Post, Hyderabad 500062, Andhra Pradesh, India.
Talanta. 2005 Jan 15;65(1):135-43. doi: 10.1016/j.talanta.2004.05.051.
The possibility of using moss (Funaria hygrometrica), immobilized in a polysilicate matrix as substrate for speciation of Cr(III) and Cr(VI) in various water samples has been investigated. Experiments were performed to optimize conditions such as pH, amount of sorbent and flow rate, to achieve the quantitative separation of Cr(III) and Cr(VI). During all the steps of the separation process, Cr(III) was selectively sorbed on the column of immobilized moss in the pH range of 4-8 while, Cr(VI) was found to remain in solution. The retained Cr(III) was subsequently eluted with 10ml of 2moll(-1) HNO(3). A pre-concentration factor of about 20 was achieved for Cr(III) when, 200ml of water was passed. The immobilized moss was packed in a home made mini-column and incorporated in flow injection system for obtaining calibration plots for both Cr(III) and Cr(VI) at low ppb levels that were compared with the plots obtained without column. After separation, the chromium (Cr) species were determined by inductively coupled plasma mass spectrometry (ICP-MS) and flame atomic absorption spectrometry (FAAS). The sorption capacity of the immobilized moss was found to be approximately 11.5mgg(-1) for Cr(III). The effect of various interfering ions has also been studied. The proposed method was applied successfully for the determination of Cr(III) and Cr(VI) in spiked and real wastewater samples and recoveries were found to be >95%.
研究了将固定在聚硅酸盐基质中的苔藓（葫芦藓）用作各种水样中Cr(III)和Cr(VI)形态分析底物的可能性。进行了实验以优化pH、吸附剂用量和流速等条件，以实现Cr(III)和Cr(VI)的定量分离。在分离过程的所有步骤中，Cr(III)在pH值为4 - 8的范围内被选择性地吸附在固定化苔藓柱上，而Cr(VI)则保留在溶液中。随后用10ml 2mol l⁻¹ HNO₃洗脱保留的Cr(III)。当通过200ml水时，Cr(III)实现了约20的预浓缩因子。将固定化苔藓填充在自制的微型柱中，并纳入流动注射系统，以获得低ppb水平下Cr(III)和Cr(VI)的校准曲线，并与无柱时获得的曲线进行比较。分离后，通过电感耦合等离子体质谱法（ICP-MS）和火焰原子吸收光谱法（FAAS）测定铬（Cr）的形态。发现固定化苔藓对Cr(III)的吸附容量约为11.5mg g⁻¹。还研究了各种干扰离子的影响。该方法成功应用于加标和实际废水样品中Cr(III)和Cr(VI)的测定，回收率>95%。
