Adsorption of Hg2+ from aqueous solution onto polyacrylamide/attapulgite.
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.
Zhao
Yijiang
Y
Chemistry Department of Huaiyin Teachers College, Key Laboratory for Chemistry of Low-Dimensional Materials of Jiangsu Province, Huaian 223300, Jiangsu Province, PR China. cyjzhao@yahoo.com
Chen
Yan
Y
Li
Meisheng
M
Zhou
Shouyong
S
Xue
Ailian
A
Xing
Weihong
W
D000180:Acrylic Resins / Q000737:chemistry*; D000327:Adsorption; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D017616:Magnesium Compounds / Q000737:chemistry*; D008628:Mercury / Q000032:analysis* / Q000302:isolation & purification*; D008689:Methacrylates / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry*; D017655:Silicon Compounds / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000302:isolation & purification; D018508:Water Purification / Q000379:methods*; D000099166:Polyacrylamides
D000180:Acrylic Resins; D017616:Magnesium Compounds; D008628:Mercury; D008689:Methacrylates; D012821:Silanes; D017655:Silicon Compounds; D014874:Water Pollutants, Chemical; D000099166:Polyacrylamides; C017492:methacryloxypropyltrimethoxysilane; C026325:attapulgite