Journal of Ecology and Rural Environment ›› 2019, Vol. 35 ›› Issue (5): 668-674.doi: 10.19741/j.issn.1673-4831.2018.0434

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Adsorption of Cd2+ by Potassium-Permanganate-Modified Wheat Straw

XIE Yu-feng1, CHENG De-yi1,2, SHI Jia-qi1, ZHU Xin1, LI Zhi-lin1,2, WANG Lei1   

  1. 1. Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing 210042, China;
    2. College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
  • Received:2018-07-24 Online:2019-05-25 Published:2019-06-25


Heavy metal ions Cd2+ were adsorbed by potassium-permanganate-modified wheat straw. The modified wheat straw was characterized by scanning electron microscopy,zeta potential,and Fourier transform infrared spectroscopy. The effects of pH,adsorption time,solid-liquid ratio,and temperature of the solution and desorption on Cd2+ adsorption were also studied. Four different concentrations of potassium-permanganate-modified wheat straw were observed. Results show that,compared with the surfaces of other concentrations,the surface of 0.05 mol·L-1 potassium-permanganate-modified wheat straw appeared smoother and had more negative charges. These outcomes were beneficial to improving the adsorption performance of Cd2+. Moreover,the adsorption reached equilibrium at 300 min and fitted the pseudo two-order kinetic equation. The best adsorption effect was obtained when the pH of the modified wheat straw was 6,and the solid-liquid ratio was 1:300. According to the Langmuir isothermal adsorption equation,the adsorbents prepared using the modified adsorbents of 0.05 mol·L-1 had the largest adsorption capacity for Cd2+ (30.21 mg·g-1)far larger than the optimum adsorption capacity of the unmodified wheat straw (5.7 mg·g-1). The adsorbent has been found to have good stability for Cd2+ adsorption.

Key words: potassium permanganate, wheat stalk, Cd2+, adsorbent, modification

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