Krishna M V Balarama, Ranjit Manjusha, Chandrasekaran K, Venkateswarlu G, Karunasagar D
National Center for Compositional Characterization of Materials (NCCCM), Bhabha Atomic Research Centre, Department of Atomic Energy, ECIL PO, Hyderabad, India.
Talanta. 2009 Oct 15;79(5):1454-63. doi: 10.1016/j.talanta.2009.06.008. Epub 2009 Jun 12.
The applicability of polyaniline (PANI) for the on-line preconcentration and recovery of palladium from various water samples has been investigated. Batch experiments were performed to optimize conditions such as pH and contact time to achieve quantitative separation of Pd spiked at high (microg ml(-1)) and low levels (ng ml(-1)). During all the steps of the removal process, it was found that Pd was selectively removed by PANI even in the presence of various ions. Quantitative removal of Pd occured in the entire studied pH range (1-12) and the K(d) value was found to be >10(6). Kinetic studies show that a contact time of <4 min was adequate to reach equilibrium. The retained Pd was subsequently eluted with a mixture of HCl and thiourea, optimized using a factorial experimental design approach. ICP-OES was used for the micro-level determinations of Pd whereas ICP-MS was used for the determination of Pd at sub-ppb levels. Breakthrough curve using column experiments demonstrated that PANI has an excellent ability to accumulate up to approximately 120 mg g(-1) of Pd from synthetic sample solutions. A preconcentration factor of about 125 was achieved for Pd when 250 ml of water was passed. PANI columns prepared were used up to 10 times in consecutive retention-elution cycles without appreciable deterioration in their performance. The proposed on-line method also has the ability to remove interfering elements Cu and Y for the determination of Pd in waters by ICP-MS. The reported method has been applied successfully for the determination of Pd in ground water, lake water sea-water and waste water samples. The recoveries were found to be >95% in all cases. These studies indicate that PANI has an excellent ability to preconcentrate Pd from various waters making the method very promising for the determination of Pd.
研究了聚苯胺（PANI）用于从各种水样中在线预富集和回收钯的适用性。进行了批量实验以优化诸如pH值和接触时间等条件，以实现对高浓度（微克/毫升(-1)）和低浓度（纳克/毫升(-1)）加标钯的定量分离。在去除过程的所有步骤中，发现即使存在各种离子，PANI也能选择性地去除钯。在整个研究的pH范围（1 - 12）内都能定量去除钯，且分配系数（K(d)）值大于10(6)。动力学研究表明，接触时间小于4分钟就足以达到平衡。随后用盐酸和硫脲的混合物洗脱保留的钯，采用析因实验设计方法对其进行了优化。使用电感耦合等离子体发射光谱仪（ICP - OES）进行钯的微量测定，而使用电感耦合等离子体质谱仪（ICP - MS）测定亚纳克/升水平的钯。柱实验的穿透曲线表明，PANI具有从合成样品溶液中出色地积累高达约120毫克/克(-1)钯的能力。当通入250毫升水时，钯实现了约125的预富集因子。制备的PANI柱在连续的保留 - 洗脱循环中使用多达10次，其性能没有明显下降。所提出的在线方法还能够去除干扰元素铜和钇以便通过ICP - MS测定水中的钯。所报道的方法已成功应用于测定地下水、湖水、海水和废水样品中的钯。在所有情况下回收率均大于95%。这些研究表明，PANI具有从各种水中出色地预富集钯的能力，使得该方法在钯的测定方面非常有前景。
