Adsorption of Pb2+, Zn2+, and Cd2+ from waters by amorphous titanium phosphate.
In the current study, amorphous titanium phosphate (TiP) was prepared as an adsorbent for heavy metals from waters. Uptake of Pb(2+), Zn(2+), and Cd(2+) onto TiP was assayed by batch tests; a polystyrene-sulfonic acid exchanger D-001 was selected for comparison and Ca(2+) was chosen as a competing cation due to its ubiquitous occurrence in waters. The pH-titration curve of TiP implied that uptake of heavy metals onto TiP is essentially an ion-exchange process. Compared to D-001, TiP exhibits more preferable adsorption toward Pb(2+) over Zn(2+) and Cd(2+) even in the presence of Ca(2+) at different levels. FT-IR analysis of the TiP samples laden with heavy metals indicated that the uptake of Zn(2+) and Cd(2+) ions onto TiP is mainly driven by electrostatic interaction, while that of Pb(2+) ions is possibly dependent upon inner-sphere complex formation, except for the electrostatic interaction. Moreover, uptake of heavy metals onto TiP approaches equilibrium quickly and the exhausted TiP particles could be readily regenerated by HCl solution.
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093, People's Republic of China.
Kun
K
Jia
Bingcai
B
Pan
Qingrui
Q
Zhang
Weiming
W
Zhang
Peijuan
P
Jiang
Changhong
C
Hong
Bingjun
B
Pan
Quanxing
Q
Zhang
D000327:Adsorption; D002104:Cadmium / Q000737:chemistry*; D002118:Calcium / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007854:Lead / Q000737:chemistry*; D008274:Magnesium / Q000737:chemistry; D010316:Particle Size; D012964:Sodium / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods; D015032:Zinc / Q000737:chemistry*
D014874:Water Pollutants, Chemical; D002104:Cadmium; D014867:Water; C036532:titanium phosphate; D007854:Lead; D012964:Sodium; D014025:Titanium; D008274:Magnesium; D015032:Zinc; D002118:Calcium