Abstract

Polyethyleneimine (PEI)-polyacrylonitrile (PAN)-cellulose membrane (PEI-PAN cellulose membrane) was developed by immobilizing PEI onto PAN coated cellulose support via electrostatic force to be used for determination of Cu(II) by colorimetric method. The membrane was prepared in two-step process, in which 4% PAN solution was prepared and coated onto the membrane via filtration method, followed by the immersion of the dried PAN-cellulose membrane in the 2% PEI solution. The morphologies of the PEI-PAN membranes were investigated with field emission scanning electron microscope. The results confirmed the presence of a coated layer on the surface. Infrared spectra of before and after coated samples were obtained by Fourier transform infrared (FTIR) spectroscope. The results showed that there were NH₂ functional group of PAN and PEI with their characteristic transmittance peaks. Determination at the parts per million level of Cu(II) (0.5–2.0 mg L^–1) was achieved by filtration of a sample solution and simultaneous colorimetric analysis using a UV-Vis spectrophotometer (at 650 nm). Cu(II) ion formed the light blue cupramine complex with PEI immobilized on the membrane by filtration of a 50 mL sample solution buffered with 0.01 M dihydrogen phosphate (pH 7). Energy dispersive X-Ray fluorescence spectrum of the Cu(II) detected membrane confirmed the capability of Cu(II) extraction of the PEI-PAN cellulose membrane from the water samples. The detection limit of the Cu(II) determination by this method was found to be 0.27 mg L^–1. The accuracy and precision of the method were estimated by Cu(II) determination at 0.5 and 2 mg L^–1 of Cu(II) solutions and the results were accurate with above 89% recovery percentage and below 5.5% relative standard deviation. Interference ions were studied and found that Fe(III) and Zn(II) slightly interfered with the Cu(II) determination. The present method was tested for the detection of treated textile wastewater and tap water spiked with 2 mg L^–1 of Cu(II). The test results were acceptable and good to determine wastewater prior to discharge into the environment that could be applied for on-site monitoring of Cu(II) in treated wastewater by filtration detection method.

中文翻译：

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聚乙烯亚胺涂层聚丙烯腈纤维素膜的比色法测定铜（II）

摘要

聚乙烯亚胺（PEI）-聚丙烯腈（PAN）-纤维素膜（PEI-PAN纤维素膜）是通过静电力将PEI固定在PAN涂布的纤维素载体上而制成的，用于比色法测定Cu（II）。该膜以两步法制备，其中制备4％PAN溶液并通过过滤法将其涂覆在膜上，然后将干燥的PAN-纤维素膜浸入2％PEI溶液中。用场发射扫描电子显微镜研究了PEI-PAN膜的形貌。结果证实了表面上存在涂层。用傅立叶变换红外光谱仪（FTIR）获得涂膜前后样品的红外光谱。结果表明存在NH ₂PAN和PEI的官能团及其特征透射峰。通过过滤样品溶液并使用UV-Vis分光光度计（在650 nm）同时进行比色分析，可以实现百万分之一的Cu（II）（0.5–2.0 mg L ^–1）含量的测定。Cu（II）离子通过过滤50 mL用0.01 M磷酸二氢钠（pH 7）缓冲的样品溶液，形成了浅蓝色铜胺配合物，PEI固定在膜上。Cu（II）检测膜的能量色散X射线荧光光谱证实了Cu（II）从水样品中提取PEI-PAN纤维素膜的能力。通过该方法测定的Cu（II）的检出限为0.27 mg L ^–1。通过在0.5和2 mg L ^–1的Cu（II）溶液中测定Cu（II）可以估算该方法的准确性和精密度，结果准确度高，回收率高于89％，相对标准偏差低于5.5％。研究了干扰离子，发现Fe（III）和Zn（II）稍微干扰了Cu（II）的测定。测试了本方法，用于检测处理过的纺织废水和掺有2 mg L ^–1的Cu（II）的自来水。测试结果是可以接受的，并且可以很好地确定废水排放到环境中之前的水平，可以通过过滤检测方法应用于处理后废水中的Cu（II）现场监测。