Study On Adsorption Of Hg (â…¡) By Thiourea And Its Derivatives Functionalized Chelating Fibers

With the rapid industrial development in global, discharge of wastewater containing heavy-metal ions at high concentrations from metal plating, mining and batteries increases continuously, which tends to increasingly serious heavy metal pollution in the aquatic environment. Among them mercury is one of the most toxic heavy metals commonly found in the biosphere due to its long-time, wide-range harm to human health and natural environment. There are many treatment technology to remove metal ions from aqueous solutions has been received widespread concern of scholars both at home and abroad. Adsorption is a commonly used method for the removal of heavy metal ions in water because of its wide material source, easy preparation and low cost. Functionalized chelating fiber belongs to the ion exchange fiber, and it has all the advantages of ion exchange fiber, but also it has fast exchange and elution speed, easy regeneration and other significant advantages.In this study, the functionalized chelating fiber was prepared by high-energy electron beam irradiation or heat treatment. A fast and selective adsorbent for Hg(II) from aqueous solution using chelating monomer functionalized polypropylene fiber grafted acrylic acid (PP-g-AA), The novel functionalized chelating fibers were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The adsorption properties of the functionalized chelating fiber for heavy metal ions Hg2+ were investigated by static adsorption experiments, discussing the initial concentration, adsorption time, temperature and pH on the adsorption process. The adsorption kinetics and adsorption isotherm models were applied to simulate the experimental data.The novel type of functional groups containing functional chelating fiber PP-g-AA-TU, PP-AA-DTB and PP-g-AA-PTU by grafting acrylic acid onto polypropylene fiber (PP-g-AA) as the matrix material, and subsequent thiourea (TU), 2,5-Dithiobiurea (DTB), N-phenyl thiourea (PTU) were modified on it by the amide condensing agent 1-(3-Dimethyla minopropyl)-3-ethylcarbodiimide hydrochloride (EDC.HC1) and N-hydroxy succinimide (NHS). Infrared spectrum analysis, scanning electron microscope, XPS prove chelating monomer was successfully modified on PP-g-AA fiber.The adsorption experiments showed that the PP-g-AA-TU, PP-g-AA-DTB, PP-g-AA-PTU fibers possess strong chelating adsorption ability for Hg(â…¡), the adsorption equilibrium could be reached within 10 min. Three kinds of chelating fiber for Hg2+ the adsorption kinetics experimental data fitted very well with the pseudo second order kinetic model and adsorption isotherm of Hg(â…¡) consistent with Langmuir model, the saturated adsorption amount reached 52.08 mg/g,66.40 mg/g and 76.51 mg/g, respectively. The adsorbents hold recyclability and a good of selectivity to Hg2+ among numerous metal ions. The pH value of the system have almost no influence on the adsorption process of Hg2+ on the PP-g-AA-TU, PP-g-AA-DTB, PP-g-AA-PTU fibers in the studied pH range (pH=2-9).