Sulfonated poly(arylene ether nitrile)/polypyrrole core/shell nanofibrous mat: an efficient absorbent for the removal of hexavalent chromium from aqueous solution

Abstract

BACKGROUND Sulfonated poly(arylene ether nitrile)/polypyrrole core/shell nanofibrous mats were prepared by an electrospinning technique, followed by in situ polymerization of pyrrole monomer. Their removal of hexavalent chromium (Cr (VI)) from aqueous solution was systematically investigated. The structure and composition of core/shell PEN/PPy nanofibrous mats were examined and confirmed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR‐FTIR), X‐ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). RESULTS The adsorption results revealed that the adsorption capacity of core/shell PEN/PPy nanofibrous mats increased with the decrease of initial solution pH and the adsorption process can be described by the pseudo‐second‐order model. These core/shell PEN/PPy nanofibrous mats showed high Cr (VI) adsorption capacity up to 165.3 mg g−1 at room temperature, which can largely be maintained after four adsorption/desorption cycles. Furthermore, the adsorption isotherms of PEN/PPy nanofibrous mats for Cr(VI) removal fitted the Langmuir isotherm model. The adsorption mechanism of electrostatic attraction between PEN/PPy nanofibrous mats was also presented. CONCLUSION The core/shell PEN/PPy nanofibrous mats in the form of flexible membrane allowed easy handling during application, and can be considered a stable and effective adsorbent for removal of heavy metals and other anionic contaminants from wastewater. © 2017 Society of Chemical Industry

Hierarchical Fe3O4‐derived organic/inorganic hybrids constructed by modified bio‐inspired functionalization: efficient adsorbents for water‐soluble methylene blue and mechanism

“…Finally, the adsorption reaches equilibrium in 2 h. Owing to the steric hindrance between solution phase and MB molecules adhering to the absorbent surface, the remaining adsorption sites are hard to occupy. Furthermore, the MB adsorption kinetics of our adsorbent is investigated by pseudo‐first‐order and pseudo‐second‐order models, as shown by the following two equations: …”

“…Typically, the randomness, spontaneity, exothermicity and endothermicity of the adsorption process for as‐prepared adsorbents can be determined by various thermodynamic parameters, including standard entropy change (Δ S °), standard Gibbs free energy change (Δ G °) and standard enthalpy change (Δ H °). In this work, these three thermodynamic parameters are calculated by the following two equations: where R , T and K c ( q e / C e ) represent the gas constant, absolute temperature and equilibrium constant respectively. Through the above two equations, a plot of ln K c vs 1000/ T is obtained ( C 0 = 60 mg L −1 ), as shown in Fig.…”

Functionalized Poly(arylene ether nitrile) Porous Membrane with High Pb(II) Adsorption Performance

“…The equilibrium adsorption capacities of SPEN-CTAB-0%, SPEN-CTAB-5% and SPEN-CTAB-15% were 183.6, 161.4 and 127.4 mg/g, respectively. In order to better understand the adsorption behavior, the adsorption data were analyzed on the basis of two commonly used kinetic models, namely the first-order kinetic model and second-order kinetic model shown in Equations (5) and (6), respectively [23,26]: logfalse(qe−qtfalse)=logqe−k12.303t tqt=1k2qe2+tqe where t (min) is the adsorption time, k 1 (min −1 ) is the rate constant of pseudo-first-order and k 2 (g/mg min) is the rate constant of pseudo-second-order.…”

“…The adsorption process is a single layer adsorption, that is, adsorption only occurred on the surface of the adsorbent. The Freundlich model can be applied to both single-layer adsorption and non-uniform surface adsorption, which can describe the mechanism of uneven surface adsorption well [23,26]. According to Figure 7 and Table 5, the obtained R 2 of the Langmuir model (0.9807) was larger than that of the Freundlich model (0.8046), which indicated that the Langmuir model was more applicable to analyze the adsorption isotherm.…”

“…Poly(arylene ether nitrile) (PEN), as a special engineering material, possesses excellent thermal stability, corrosion resistance and maneuverability on account of its rigid benzene ring structure and adjustable side chain [23,24]. Meanwhile, it can be prepared into microspheres, fibers, membranes, etc., owing to the diversity of its preparation processes.…”