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An electrically controlled and renewable hydrophobic surface used to trap and release three test pollutants on an indium-tin-oxide (ITO) electrode is presented. Oxygen plasma was used to maximize the activated hydroxyl groups on the ITO surface, which were reacted with (3-aminopropyl) triethoxysilane (APTES) to create a 3-amino propyl layer. Copper(II) ions were introduced and attached to the terminal amine groups. The amine group from 1-hexadecylamine (HDA), complexed the surface-confined copper(II) ions, which resulted in terminal hexadecyl alkyl groups. The created hydrophobic surface was tested for its ability to adsorb pollutant substances, namely bisphenol-A, 2-naphthol, and doxepin. Desorption was accomplished by reducing copper(II) to copper(0) electrochemically. This led to the weakening of the metal-amine complex and the concomitant detachment of the HDA and trapped species from the ITO surface. Efficient trapping and releasing of bisphenol-A (1 ppm) was achieved with around 84% adsorption, 100% desorption (in a time course of less than 30 s), and 42-fold enrichment on the concentration. After each adsorption/desorption trial, regeneration of the hydrophobic surface was achieved by reapplication of copper(II) ions and HDA. Five cycles were successfully repeated without any significant deterioration in performance. Similar trap-and-release performance was also attained for 2-naphthol and doxepin.

Removal of hexavalent chromium Cr (VI) from water is a key problem in environmental remediation due to its high toxicity. In this work, a special sol of iron alkoxide was first prepared and added into a polymer (thermal plastic elastomer ester (TPEE)) solution to form the electrospinning precursor, then for the first time, hierarchically nanofibrous membrane was fabricated by electrospinning technique combined with hydrothermal strategy. The synthesized membrane exhibited high efficiency for the removal of Cr (VI) from water. X-ray diffraction (XRD) and scanning electron microscopy (SEM) revealed that the resulting nanofibrous membrane posses high crystallinity as well as hierarchical structure. The controlled experiments results and X-ray photoelectron spectroscopy (XPS) characterization indicated that the Cr (VI) removal ability of the membrane was mainly attributed to the adsorption and reduction of Cr (VI)–Cr (III), which is much less toxic, because of the hierarchical structure and the exposed iron oxide active sites. The research of adsorption isotherm suggested that the adsorption of Cr onto the membrane was Freundlich adsorption, which further displayed that the main Cr (VI) removal was attributed to the reduction of Cr (VI)–Cr (III). Therefore, this study provides a promising hierarchically nanostructured membrane with desirable Cr (VI) removal ability and easy solid–liquid separation property.