Preparation Of Polyacrylonitrile - Based Nanofibers And Their Adsorption Properties For Copper Ion

Along with the rapid industrial development, application of heavy metal has been used more and more widely, which has become a threat to human health and environment. Copper as micronutrients is indispensible to human body health, but the excessive copper will produce negative effects. Enrichment of copper in the ecological environment is easy to enter the body through the food chain finally, which causes serious threat to human health. Thus, removal of the copper ions in the wastewater is important, in case of environmental pollution and human disease by sewage discharge. Compared with other methods, adsorption is one of the most promising treatments for the removal of metal ions because it is simple and cost-effective.In this study, based on polyacrylonitrile, nanofiber membrane was produced by electrospinning and the best spinning process was determined under different pinhole specifications and different spinning concentrations according to the structure and morphology of nanofiber membrane. Heavy metal ions adsorbent materials were prepared by chemically modifying and compounding with graphene oxide. The adsorption performance of adsorbent materials for copper ion in aqueous solution were investigated. The results are listed as follows:(1) Polyacrylonitrile (PAN) nanofibers produced by electrospinning technique were chemically modified with ethylenediamine (EDA), the effects of amination conditions on the morphology of nanofiber membrane was investigated. The properties and morphology of the prepared nanofiber adsorbent were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM). The influence of pH, contact time and initial concentrations on the adsorption of copper ions were investigated and the reasons were analysed. The results indicated that the Langmuir and pseudo-second order models fit the adsorption better than the others, the adsorption reached equilibria when pH was 5 and contact time was 120 min and the maximum adsorption capacity was 54 mg/g. The calculated thermodynamic parameters indicated that the adsorption of Cu(â…¡) on adsorbent was endothermic. It was seen that there was still good adsorption amount for Cu2+ions after six adsorption-desorption cycles.(2) Graphene oxide (GO) assimilated with polyacrylonitrile by electrospinning were prepared to remove heavy metal Cu(II) from an aqueous solution. The morphology of the prepared nanofiber adsorbent were characterized by SEM. The effects of pH, contact time and initial concentrations on the adsorption of copper ions were investigated. The adsorption isotherms were determined by Langmuir and Freundlieh equation and to study kinetics and thermodynamics of the adsorption process. The results show that the adsorption reached equilibria when pH was about 5 and contact time was 120 min and the maximum adsorption capacity was 18.2 mg/g. The Langmuir and pseudo-second order models fit the adsorption.