The present research was aimed at the modify of natural sands with NaOH in different concentration,the condition of mod-ifying was optimized. the size distribution,the surface morphology,the surface area,the hole volume and the functional radical of MNSs were analyzed using FTIR,SEM,NSA;after modifying,the surface morphology was changed,the surface area and hole volume were increased;adsorption properties of Pb( II) onto modified natural sands( MNSs) and separation of trace Pb( II) from aqueous so-lution were mainly studied using FAAS as determination measures. the adsorption of Pb( II) onto MNSs were optimized. The experi-mental results showed that at the optimal adsorption conditions such as,the procedure was carried at room temperature,pH of solu-tion was 5. 5,the flow rate(mL·min-1)of sample and eluent were1. 5 and 3. 0 respectively,the adsorption capacity of Pb(II)onto MNSs can reach 32. 6 mg·g-1 . Adsorption rate was 93. 6%. surface area,pore size and hole volume were 12. 55m2·g-1 ,25. 29nm and 48. 04mm3·g-1(D<8. 3 nm)separately. Pb2+ ions preconcentrated on MNSs was eluted with 0. 5mol·L-1 chloride acid. the de-sorption rate reached 97%.%本文用不同浓度的氢氧化钠溶液修饰天然沙粒并通过扫描电镜、静态氮吸附和红外光谱法考察了修饰天然沙粒的表面结构、比表面积和功能基团,优化了修饰条件；以修饰天然沙粒为填料制备分离富集微柱,采用FAAS着重研究了修饰沙粒对Pb2+的动态吸附及其在痕量Pb2+分离富集和测定中的应用；结果表明：天然沙粒被修饰后其表面形貌、比表面积、表面孔体积和粒径分布发生变化,表面变得更粗糙,孔体积和比表面积增大,硅羟基红外吸收峰强度也明显增强；其比表面积为12．55m2/g,平均孔(坑)径为25．29nm,平均孔体积48．04mm3/g(D<8．3 nm)；在室温下,溶液pH为5．5,上样流速为1．50mL·min-1时,修饰天然沙粒对Pb2+的动态吸附量可达到32．6 mg·g-1,吸附率为93．6%,选用0．5mol·L-1的盐酸溶液以3．0mL·min-1流速进行洗脱,洗脱率为97%；适用于痕量Pb2+的分离富集和测定,结果令人满意。
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