Adsorption of Hg2+ from aqueous solution onto polyacrylamide/attapulgite

J Hazard Mater. 2009 Nov 15;171(1-3):640-6. doi: 10.1016/j.jhazmat.2009.06.048. Epub 2009 Jun 18.

Abstract

Polyacrylamide/attapulgite (PAM/ATP) was prepared by the solution polymerization of acrylamide (AM) onto gamma-methacryloxypropyl trimethoxy silane (KH-570)-modified attapulgite (ATP). PAM/ATP was characterized using Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). The effects of contact time, adsorbent dosage, and pH of the initial solution on the adsorption capacities for Hg(2+) were investigated. The adsorption process was rapid; 88% of adsorption occurred within 5 min and equilibrium was achieved at around 40 min. The equilibrium data fitted the Langmuir sorption isotherms well, and the maximum adsorption capacity of Hg(2+) onto PAM/ATP was found to be 192.5 mg g(-1). The adsorption kinetics of PAM/ATP fitted a pseudo-second-order kinetic model. Our results suggest that chemisorption processes could be the rate-limiting steps in the process of Hg(2+) adsorption. Hg(2+) adsorbed onto PAM/ATP could be effectively desorbed in hot acetic acid solution, and the adsorption capacity of the regenerated adsorbents could still be maintained at 95% by the sixth cycle.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acrylic Resins / chemistry*
  • Adsorption
  • Hydrogen-Ion Concentration
  • Kinetics
  • Magnesium Compounds / chemistry*
  • Mercury / analysis*
  • Mercury / isolation & purification*
  • Methacrylates / chemistry*
  • Silanes / chemistry*
  • Silicon Compounds / chemistry*
  • Spectrometry, X-Ray Emission
  • Spectroscopy, Fourier Transform Infrared
  • Time Factors
  • Waste Disposal, Fluid / methods
  • Water Pollutants, Chemical / analysis*
  • Water Pollutants, Chemical / isolation & purification
  • Water Purification / methods*

Substances

  • Acrylic Resins
  • Magnesium Compounds
  • Methacrylates
  • Silanes
  • Silicon Compounds
  • Water Pollutants, Chemical
  • methacryloxypropyltrimethoxysilane
  • polyacrylamide
  • Mercury
  • attapulgite