Adsorption of copper(II), nickel(II) and cobalt(II) ions from aqueous solution by methacrylic acid/acrylamide monomer mixture grafted poly(ethylene terephthalate) fiber

A reactively fibrous adsorbent was prepared by graft copolymerization of methacrylic acid (MAA)/acrylamide (AAm) monomer mixture onto poly(ethylene terephthalate) (PET) fiber and characterized by Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA). The adsorption of Cu(II), Ni(II) and Co(II) ions from aqueous solution by the reactive fiber was examined by batch equilibration technique. The effects of graft yield, pH, adsorption time, initial ion concentrations and adsorption temperature on the adsorption amount of ions were investigated. The reusability and selectivity of the reactive fiber were also investigated. The results showed that the adsorption of the metal ions followed the following order Cu(II) > Ni(II) > Co(II). The adsorption amounts of ions increased with the increase of grafting yield, shaking time, and pH of the medium. The adsorption amounts of Ni(II) and Co(II) ions increased but Cu(II) ions were not affected with increasing adsorption temperature. It was found that the adsorption isotherm of the ions fitted Langmuir-type isotherms. From the Langmuir equation the adsorption capacity was found as 31.25 mg/g fiber for Cu(II), 43.48 mg/g fiber for Ni(II), and 27.17 mg/g fiber for Co(II), respectively. The competitive adsorption tests verified that this reactive fiber possessed good adsorption selectivity for Cu(II) with the coexistence of Co(II) and Ni(II). It can be regenerated by 1 M HNO3 without losing their activity.