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چکیده
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Chromium (Cr), as a highly toxic heavy metal ion, is still a severe environmental issue, although many research eforts have been put into its removal from water. Polyaniline (PANI), as a conductive polymer, demonstrated great capability in heavy metal adsorption due to its low cost, ease of synthesis, reversible redox behavior, and chemical stability. However, using PANI powder alone in heavy metal removal causes secondary pollution and aggregation in water. The PANI coating on a substrate could tackle this problem. In this study, polyaniline-coated polyamide6 (PA6/PANI) nano-web membrane was used for the removal of Cr(VI) in both adsorption and fltration-adsorption modes. The PA6/PANI nano-web membrane was fabricated via PA6 electrospinning followed by in-situ polymerization of the aniline monomer. The electrospinning condition of PA6 was optimized by the Taguchi method. The PA6/PANI nano-web membrane was characterized by FESEM, N 2-adsorption/desorption, FT-IR, contact angle measurement, and tensile test. FT-IR and FESEM results demonstrated the successful synthesis of PA6/PANI nano-web and PANI homogeneous coating on PA6 nanofbers, respectively. The N2 adsorption/desorption results indicated that the pore volume of the PA6/PANI nano-web decreased by 39% compared to PA6 nanofbers. The tensile test and water contact angle studies showed that the coating of PANI on PA6 nanofbers improves the mechanical properties and hydrophilicity of PA6 by 10% and 25%, respectively. The application of PA6/PANI nano-web in the removal of Cr(VI) in batch and fltration modes exhibits excellent removal of 98.4 and 86.7%, respectively. A pseudo frst order model well described the adsorption kinetics, and the adsorption isotherm was best ftted by the Langmuir model. A black box modeling approach based on artifcial neural networks (ANN) was developed to predict the removal efciency of the membrane. The superior performance of PA6/PANI in both adsorption and fltration-adsorption systems makes it a potential candidate for the removal of heavy metals from water on an industrial scale.
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