Polyaniline Coated Ethyl Cellulose with Improved Hexavalent Chromium Removal

Abstract

The ethyl celluloses (ECs) modified with 5.0, 10.0, and 20.0 wt % polyaniline (PANI) (PANI/ECs) prepared by homogeneously mixing the EC and PANI formic acid solutions have demonstrated a superior hexavalent chromium (Cr­(VI)) removal performance to that of pure EC. Having an increased Cr­(VI) removal percentage with increased PANI loading, the PANI/ECs with 20.0% PANI loading were noticed to remove 2.0 mg/L Cr­(VI) completely within 5 min, much faster than the pristine EC (>1 h). A chemical redox of Cr­(VI) to Cr­(III) by the active functional groups of PANI/ECs was revealed from the kinetic study. Meanwhile, isothermal study demonstrated a monolayer adsorption behavior following the Langmuir model with a calculated maximum absorption capacity of 19.49, 26.11, and 38.76 mg/g for the 5.0, 10.0, and 20.0 wt % PANI/ECs, much higher than that of EC (12.2 mg/g). The Cr­(VI) removal mechanisms were interpreted considering the functional groups of both PANI and EC, the valence state fates of Cr­(VI), and the variation of solution acidity.

Polyethylenimine Facilitated Ethyl Cellulose for Hexavalent Chromium Removal with a Wide pH Range

“…The adsorption process was found to fit better with a pseudo-second-order model with a correlation more than 0.99 ( Figure 4B), indicating a chemical adsorption controlled adsorption rate. 19 It is consistent with the results based on FT-IR ( Figure 5A) and XPS ( Figure 5, panels B−E), showing the reduction of Cr(VI) to Cr(III) by PEI/ECs. Two isotherm models (i.e., Langmuir 3,19 and Freundlich) 3,19 were used to fit the Cr(VI) removal process by PEI/ECs.…”

Polypyrrole/NiFe2O4 composites with improved hexavalent chromium removal from aqueous solution

“…Kinetics models are used to find the potential rate‐controlling step involved in the Cr(VI) removal process by PPy/NiFe 2 O 4 composites. Similar kinetics was also observed for the Cr(VI) adsorption for many adsorbents, such as magnetic NPs , PANI , PANI/ethyl celluloses , and ion imprinted polymer . In this study, two models, Pseudo‐first‐order and Pseudo‐second‐order, were used to evaluate the kinetics of Cr(VI) removal by PPy/NiFe 2 O 4 composites.…”

Facile Synthesis of Well-Dispersed Superparamagnetic γ-Fe2O3 Nanoparticles Encapsulated in Three-Dimensional Architectures of Cellulose Aerogels and Their Applications for Cr(VI) Removal from Contaminated Water

“…So far, all sorts of adsorbents including natural materials (e.g., clay, rice husk ash, activated alumina, fuller's earth, fly ash, saw dust) and synthetic materials (e.g., active carbon, mesoporous silica, polyaniline coated ethyl cellulose) have been carried out to treat with Cr(VI)-containing wastewater. [50][51][52][53][54] However, compared with these adsorbents, γ-Fe 2 O 3 @CA has not only good environmental benefits and strong 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 selectiveness in Cr(VI) removal, 55 but also excellent magnetic responsibility contributing to achieving a given level of magnetic separation with much less energy. Besides, due to the large specific surface area and 3D hierarchical porous structure of the aerogels template as well as good dispersion of nanoparticles, we expect that the hybrid γ-Fe 2 O 3 @CA will display a synergistic effect of obtaining a strong ability to adsorb Cr(VI).…”