Abstract

New test systems made of nanofibers based on polyacrylonitrile and modified by NaOH are obtained for the chemisorption preconcentration of heavy metal (HM) ions and the subsequent colorimetric determination of their total amount . The kinetics of the adsorption of HM ions is studied, and corresponding adsorption isotherms are obtained. The adsorption capacities of nanofiber adsorbents for Mn²⁺, Co²⁺, Cu²⁺, Pb²⁺, and Fe³⁺ equal 52, 87, 126, 153, and 162 mg/g, respectively. The distribution and concentration coefficients of HM ions are calculated. The hydrophilic–hydrophobic properties of the nanofibers are estimated from the calculated values of limiting wetting angles and water resistance. Examples of the quantitative assessment of the total of ultra-small amounts of HM ions in model solutions and real samples (natural and drinking water) by the mathematical processing of digital images of colored areas of test facilities are given. It is shown that the developed color scale ensures the determination of the excess of total HM ions in natural water over the maximum permissible concentration (>20 μg/L), which was confirmed by the results of determination by atomic absorption spectrometry.

中文翻译：

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基于聚丙烯腈的改性纳米纤维对重金属离子的富集和测试测定

摘要

获得了一种新的由聚丙烯腈基纳米纤维制成并经NaOH改性的测试系统，用于重金属（HM）离子的化学吸附预富集和随后的比色测定。研究了HM离子的吸附动力学，并获得了相应的吸附等温线。纳米纤维吸附剂对Mn 2 ⁺，Co 2 ⁺，Cu 2 ⁺，Pb ²⁺和Fe ³⁺的吸附能力分别等于52、87、126、153和162 mg / g。计算了HM离子的分布系数和浓度系数。纳米纤维的亲水性-疏水性是根据极限润湿角和耐水性的计算值估算的。通过对测试设施有色区域的数字图像进行数学处理，给出了对模型溶液和实际样品（天然和饮用水）中超微量HM离子总量进行定量评估的示例。结果表明，所开发的色标可确保对天然水中总HM离子过量的测定超过最大允许浓度（> 20μg/ L），这已通过原子吸收光谱法的测定结果得到证实。