U TILIZATION of electrospinning technique accompanied by chemical modification as well as, the production of low-cost adsorbent based on polyamide nanofibers is the aim of our current work. The electrospinning parameters (polymer conc, applied voltage, and collector distance) have been studied. The obtained polyamide nanofiber mats were modified with citric acid at various conditions (concentration, temperature and catalyst concentration). The optimum conditions of this modification were investigated by MB uptake efficiency. The obtained data illustrate a positive relationship between citric acid concentration and MB uptake using the modified polyamide nanofiber. The produced adsorbent was well characterized using SEM, ATR-FTIR, and surface area measurement. Scanning Electron Microscopy clarifies minor swelling of nanofibers during the modification process which attributed to the increase in fiber diameter and therefore reduction in the fiber surface area. The adsorption performance of the nanofiber mat was assessed as a function of pH, nanofiber mat dosage, contact time, and initial dye concentration. Kinetics and isotherms analysis were investigated as well. The MB separation capability of the modified PA-nanofiber was considerably higher than that of the PAnanofiber. The kinetic data of both nanofiber mat was better fitted with the pseudo-second-order model. Also, the equilibrium data of PA-nanofiber was better fitted with Freundlich model and Langmuir model in case of the modified PA-nanofiber. The adsorption behavior was favorable chemisorption process as inferred from the kinetics, and the isotherms studies. The results of this study promote the modified PA-nanofiber as a potential adsorption filters for dyeing wastewater decolourization.

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A B S T R A C TWaste wool fibers (WF) were oxidized and ball milled to enhance the exchanging ability toward some metal ions, namely copper and zinc. Wool fibers were oxidized with hydrogen peroxide and tetra acetyl ethylene diamine, followed by grinding process. Optimization of the exchanging medium with regard to the metal ion concentration, pH, and exchanging time was performed. It was observed that the ability of the wool powder (WP) and oxidized wool powder (OWP) to exchange greater amount of metal ions than the ordinary waste wool fibers. Mostly, current results verify a significant ability of the OWP to exchange copper and zinc ions from their aqueous medium. Nevertheless, the ability of all wool substrates used to exchange copper is more than their ability to exchange zinc, and as the pH of the exchanging medium increases, the uptake % of both copper and zinc ions by WF or WP increases to reach its maximum at pH 6. The efficiency of WF, WP, or OWP to adsorb copper and zinc ions after a number of adsorption/desorption tests was also studied.

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