Department of Chemistry, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah, 21589, Saudi Arabia,
Environ Monit Assess. 2013 Dec;185(12):10269-80. doi: 10.1007/s10661-013-3331-z. Epub 2013 Jul 7.
New solid-phase extractor (MWCNTs-5-ASA) was synthesized via covalent immobilization of 5-aminsalicylic acid onto multi-walled carbon nanotubes (MWCNs). The success of the functionalization process was confirmed using Fourier transform infrared spectroscopy, scanning electron microscope, and surface coverage determination. Batch experiments were conducted as a function of pH to explore MWCNTs-5-ASA efficiency to extract several metal ions viz., Cr(III), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II). It was found that Pb(II) exhibits the highest extraction percentage with maximum adsorption capacity 32.75 mg g(-1). Its binding performance was well fitted with Langmuir sorption isotherm. On the other hand, the selective separation and preconcentration of trace Pb(II) under dynamic conditions prior to determination by inductively coupled plasma-optical emission spectrometry was investigated under different parameters. These included the rate of flow and volume of sample solution, in addition to the type of the eluate, its volume and concentration. The effect of a variety of foreign ions on the recovery percentage was also evaluated. Trace Pb(II) ions present in 500 mL aqueous solution adjusted to pH 4.0 were retained on 50 mg of MWCNTs-5-ASA and completely eluted using 4.0 mL of 2 M HNO₃. The limit of detection and the precision of the method were 0.25 ng mL(-1) and 2.8%, respectively (N = 5). This methodology has been applied for the determination of Pb(II) in water samples with good results.
新型固相萃取剂（MWCNTs-5-ASA）是通过将 5-氨基水杨酸共价固定在多壁碳纳米管（MWCNs）上合成的。傅里叶变换红外光谱、扫描电子显微镜和表面覆盖度测定证实了功能化过程的成功。通过 pH 值的批实验，研究了 MWCNTs-5-ASA 从多种金属离子（如 Cr(III)、Fe(III)、Co(II)、Ni(II)、Cu(II)、Zn(II)、Cd(II)和 Pb(II)）中提取的效率。结果表明，Pb(II) 的萃取率最高，最大吸附容量为 32.75mg/g。其结合性能与 Langmuir 吸附等温线拟合良好。另一方面，在电感耦合等离子体-光学发射光谱法测定之前，在动态条件下，对痕量 Pb(II)的选择性分离和预浓缩进行了研究，考察了不同参数的影响。这些参数包括流速和样品溶液的体积，以及洗脱液的类型、体积和浓度。还评估了多种外来离子对回收率的影响。将 pH 值调整为 4.0 的 500mL 水溶液中的痕量 Pb(II)离子保留在 50mg MWCNTs-5-ASA 上，并使用 4.0mL 2M HNO₃完全洗脱。该方法的检测限和精密度分别为 0.25ng/mL 和 2.8%（N=5）。该方法已成功应用于水样中 Pb(II)的测定，结果令人满意。
