Raju Ch Siva Kesava, Subramanian M S
Department of Chemistry, Indian Institute of Technology, Chennai 600036, India.
Talanta. 2005 Jul 15;67(1):81-9. doi: 10.1016/j.talanta.2005.02.003.
A new class of polymeric resin has been synthesized by grafting Merrifield chloromethylated resin with (dimethyl amino-phosphono-methyl)-phosphonic acid (MCM-DAPPA), for the preconcentration of U(VI), Th(IV) and La(III) from both acidic wastes and environmental samples. The various chemical modification steps involved during grafting process are characterized by FT-IR spectroscopy, (31)P and (13)C-CPMAS (cross-polarized magic angle spin) NMR spectroscopy and CHNS/O elemental analysis. The water regain capacity data for the grafted polymer are obtained from thermo-gravimetric (TG) analysis. The influence of various physico-chemical parameters during the quantitative extraction of metal ions by the resin phase are studied and optimized by both static and dynamic methods. The significant feature of this grafted polymer is its ability to extract both actinides and lanthanides from high-level acidities as well as from near neutral conditions. The resin shows very high sorption capacity values of 2.02, 0.89 and 0.54mmolg(-1) for U(VI), 1.98, 0.63 and 0.42mmolg(-1) for Th(IV) and 1.22, 0.39 and 0.39mmolg(-1) for La(III) under optimum pH, HNO(3) and HCl concentration, respectively. The grafted polymer shows faster phase exchange kinetics (<5min is sufficient for 50% extraction) and greater preconcentration ability, with reusability exceeding 20 cycles. During desorption process, all the analyte ions are quantitatively eluted from the resin phase with >99.5% recovery using 1M (NH(4))(2)CO(3), as eluent. The developed grafted resin has been successfully applied in extracting Th(IV) from high matrix monazite sand, U(VI) from sea water and also U(VI) and Th(IV) from simulated nuclear spent fuel mixtures. The analytical data obtained from triplicate measurements are within 3.9% R.S.D. reflecting the reproducibility and reliability of the developed method.
通过将Merrifield氯甲基化树脂与（二甲基氨基膦酰甲基）膦酸（MCM-DAPPA）接枝，合成了一类新型聚合物树脂，用于从酸性废物和环境样品中预富集U(VI)、Th(IV)和La(III)。接枝过程中涉及的各种化学改性步骤通过傅里叶变换红外光谱（FT-IR）、（31）P和（13）C交叉极化魔角旋转（C-CPMAS）核磁共振光谱以及CHNS/O元素分析进行表征。接枝聚合物的回潮率数据通过热重分析（TG）获得。通过静态和动态方法研究并优化了树脂相定量萃取金属离子过程中各种物理化学参数的影响。这种接枝聚合物的显著特点是能够从高酸度以及近中性条件下萃取锕系元素和镧系元素。在最佳pH值、硝酸和盐酸浓度下，该树脂对U(VI)的吸附容量分别为2.02、0.89和0.54 mmol g(-1)，对Th(IV)的吸附容量分别为1.98、0.63和0.42 mmol g(-1)，对La(III)的吸附容量分别为1.22、0.39和0.39 mmol g(-1)。接枝聚合物显示出更快的相交换动力学（50%萃取只需<5分钟）和更强的预富集能力，可重复使用超过20次。在解吸过程中，使用1M (NH4)2CO3作为洗脱剂，所有分析物离子从树脂相中定量洗脱，回收率>99.5%。所开发的接枝树脂已成功应用于从高基体独居石砂中萃取Th(IV)、从海水中萃取U(VI)以及从模拟核废料混合物中萃取U(VI)和Th(IV)。三次重复测量获得的分析数据的相对标准偏差（R.S.D.）在3.9%以内，反映了所开发方法的重现性和可靠性。
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