Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing, 210096, China.
Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing, 210096, China.
Chemosphere. 2020 Nov;258:127373. doi: 10.1016/j.chemosphere.2020.127373. Epub 2020 Jun 13.
The development of an adsorbent with high adsorption ability and favorable cyclic regeneration performance for the removal of nitrate residues from wastewater is a task of vital importance. To this end, polyacrylonitrile fiber (PANF) was modified with polyethyleneimine (PEI), and alkyl groups were then introduced around the active amine groups to prepare three polymer-based anion exchange fibers (PAN-PEI-3C, PAN-PEI-5C, and PAN-PEI-8C). The novel fibers were characterized using techniques such as scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). The adsorption isotherms of the fibers were best fitted by the Langmuir model, and PAN-PEI-5C exhibited a higher adsorption amount of nitrate (31.32 mg/g) than the other adsorbents. The equilibrium was reached expeditiously (within 10 min), and both pseudo-first-order and pseudo-second-order models could well describe the adsorption kinetics. More attractively, the saturated PAN-PEI-5C could be eluted using a low-concentration (0.3 M) NaCl solution, without any sharp loss of adsorption amount for five consecutive cycles in the presence of dissolved organic matter (DOM). Furthermore, PAN-PEI-5C could effectively adsorb low-concentration nitrate from real secondary effluents in a fixed-bed column experiment. Our work provides a promising and low-cost material for the removal of nitrate residues in practical applications.
开发一种具有高吸附能力和良好循环再生性能的吸附剂，用于去除废水中的硝酸盐残留，这是一项至关重要的任务。为此，用聚乙烯亚胺（PEI）对聚丙烯腈纤维（PANF）进行了改性，然后在活性胺基团周围引入烷基基团，制备了三种基于聚合物的阴离子交换纤维（PAN-PEI-3C、PAN-PEI-5C 和 PAN-PEI-8C）。采用扫描电子显微镜（SEM）、能谱（EDS）、傅里叶变换红外光谱（FTIR）、X 射线光电子能谱（XPS）和热重分析（TGA）等技术对新型纤维进行了表征。纤维的吸附等温线最好用朗缪尔模型拟合，而 PAN-PEI-5C 对硝酸盐的吸附量（31.32 mg/g）高于其他吸附剂。平衡迅速达到（在 10 分钟内），并且伪一级和伪二级模型都可以很好地描述吸附动力学。更吸引人的是，饱和的 PAN-PEI-5C 可以用低浓度（0.3 M）NaCl 溶液洗脱，在存在溶解有机物（DOM）的情况下，连续五个循环没有任何明显的吸附量损失。此外，在固定床柱实验中，PAN-PEI-5C 可以有效地从实际二级出水中吸附低浓度的硝酸盐。我们的工作为实际应用中去除硝酸盐残留提供了一种有前途且低成本的材料。
