Efficient removal of Pb(II), Cd(II), Cu(II) and Ni(II) from aqueous solutions by tetrazole-bonded bagasse

摘要

The bagasse as raw materials, were soaked in 40% sodium hydroxide for pre-swelling and dried 100% weight gain, then etherified with acrylonitrile to obtain acrylonitrile modified bagasse (ANB). Subsequently, tetrazole-bonded bagasse (TAB) was prepared by a click chemistry reaction between the nitrile group and the azide group with ammonium chloride as catalyst. Fourier-transform infrared spectrometry and X-ray photoelectron spectroscopy were used to characterize the surface composition of the TAB adsorbents. The maximum adsorption capacities of the TAB adsorbents were up to 253.5 mg g(-1) for Pb (II), 196.8 mg g(-1) for Cd (II), 132.5 mg g(-1) for Cu (II) and 89.3 mg g(-1) for Ni (II) at pH 5.0, respectively. The adsorption kinetics of four metal ions conform to the model of pseudo second-order kinetic, and adsorption equilibrium were better characterized by the Langmuir equation. Thermodynamic parameters were calculated to understand the nature of adsorption process. The adsorption of the four concerned metal ions was hardly affected by common coexisting ions such as Na(I), K(I), Ca(II) and Mg(II), whereas they were slightly decreased when Fe(III) and Zn(II) coexisted in the solution, which illustrates the selective adsorption of Pb(II), Cd(II), Cu(II) and Ni(II) from wastewater. The TAB adsorbents possesses excellent desorption rate and reusability. All these results indicate that the TAB adsorbents could be potentially applied to the efficient removal of heavy metal ions from waste water.