Preparation and application of functionalized cellulose acetate/silica composite nanofibrous membrane via electrospinning for Cr(VI) ion removal from aqueous solution

Novel NH(2)-functionalized cellulose acetate (CA)/silica composite nanofibrous membranes were successfully prepared by sol-gel combined with electrospinning technology. Tetraethoxysilane (TEOS) as a silica source, CA as precursor and 3-ureidopropyltriethoxysilane as a coupling agent were used in membrane preparation. The membrane's chemical and morphological structures were investigated by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) images, X-ray diffraction (XRD), element analyzer, Fourier-transform infrared spectroscopy (FTIR) and N(2) adsorption-desorption isotherms. The composite nanofibrous membranes exhibited high surface area and porosity. The membranes were used for Cr(VI) ion removal from aqueous solution through static and dynamic experiments. The adsorption behavior of Cr(VI) can be well described by the Langmuir adsorption model, and the maximum adsorption capacity for Cr(VI) is estimated to be 19.46 mg/g. The membrane can be conveniently regenerated by alkalization. Thus the composite membrane prepared from biodegradable raw material has potential applications in the field of water treatment.

Preparation and application of amino functionalized mesoporous nanofiber membrane via electrospinning for adsorption of Cr3+ from aqueous solution

Novel amino (-NH2) functionalized mesoporous polyvinyl pyrrolidone (PVP)/SiO2 composite nanofiber membranes were fabricated by a one-step electrospinning method using poly (vinyl alcohol) and tetraethyl orthosilicate (TEOS) mixed with cationic surfactant, cetyltrimethyl ammonium bromide (CTAB) as the structure directing agent. Ureidopropyltriethoxysilane was used for functionalization of the internal pore surfaces. The membranes were characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM) images, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), element analyzer and N2 adsorption-desorption isotherms. The nanofiber diameters, average pore diameters and surface areas were 100-700 nm, 2.86 nm and 873.62 m2/g, respectively. These mesoporous membranes functionalized with -NH2 groups exhibited very high adsorptions properties based on the adsorption of Cr3+ from an aqueous solution. Equilibrium adsorption was achieved after approximately 20 min and more than 97% of chromium ions in the solution were removed. The membrane could be regenerated through acidification.