Removal of Cu(II) from aqueous solution by adsorption on Chinese Quaternary loess: kinetics and equilibrium studies.
This paper dealt with the characteristics of Cu(II) adsorption on Chinese Quaternary loess. The Cu(II) adsorption isotherm and kinetics fit the Langmuir model and pseudo-second order kinetics well, respectively, with a predicted adsorption capacity of 109 mg g(-1). The adsorption is ion exchange adsorption due to D-R model. Factors that are positively correlated with the adsorption capacity of loess include equilibrating time, pH, temperature, and solid-solution ratio. The adsorption of Cu(II) on loess involves 2-3 sequential diffusing steps into the micropores, and an endothermic and spontaneous process with predicted enthalpy, entropy, and Gibb's free energy changes of 7.64 kJ mol(-1), 81.21 J mol(-1)K(-1) and -14.94-17.37 kJ mol(-1), respectively. Moreover, the applicability of loess on industrial wastewater treatment was investigated and satisfactorily proved. Finally, FT-IR spectra shows the precipitation of copper carbonate and the complexation of Cu(II) with clay minerals at pH > 5.0 and pH > 2.67, respectively.
Tang
Xiao W
XW
Key Laboratory of Soft Soils and Geoenvironmental Engineering, Zhejiang University, Hangzhou, PR China. tangxiaowu@zju.edu.cn
Li
Zhen Z
ZZ
Chen
Yun M
YM
Wang
Yan
Y
D000327:Adsorption; D000465:Algorithms; D002681:China; D003300:Copper / Q000737:chemistry / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D012987:Soil / Q000032:analysis*; D012989:Soil Pollutants / Q000737:chemistry / Q000302:isolation & purification*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013696:Temperature; D013816:Thermodynamics; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification; D018508:Water Purification / Q000379:methods
D012987:Soil; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D003300:Copper