Enhanced photocatalytic reduction of aqueous Pb(II) over Ag loaded TiO2 with formic acid as hole scavenger.
In the present study, photocatalytic Pb(II) reduction over TiO(2) and Ag/TiO(2) catalysts in the presence of formic acid was explored to eliminate Pb(II) pollution in water. Ag/TiO(2) catalysts were prepared by the photo-deposition method and characterized using UV-Vis diffuse reflectance spectra, X-ray reflection diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. Ag deposition on TiO(2) led to enhanced photocatalytic Pb(II) reduction and the Ag/TiO(2) catalyst with a Ag loading amount of 0.99 wt.% exhibited the optimum photocatalytic activity. For Pb(II) reduction over Ag/TiO(2) with a Ag loading amount of 0.99 wt.%, initial Pb(II) reduction rate was found to be dependent on the initial concentrations of formic acid and Pb(II). Increasing initial Pb(II) concentration led to linearly increased initial Pb(II) reduction rate. At low formic acid concentration, in parallel, initial Pb(II) reduction rates increased with formic concentration, but remained nearly identical at high formic acid concentration. Solution pH impacted the photocatalytic Pb(II) reduction and after irradiation for 100 min Pb(II) was removed by 11.8%, 91.2% and 98.6% at pH of 0.8, 2.0 and 3.5, respectively, indicative of enhanced Pb(II) reduction with pH in the tested pH range. The results showed that Ag/TiO(2) displayed superior catalytic activity to TiO(2), highlighting the potential of using Ag/TiO(2) as a more effective catalyst for photocatalytic Pb(II) reduction.
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, PR China.
Liyuan
L
Li
Fang
F
Jiang
Jingliang
J
Liu
Haiqin
H
Wan
Yuqiu
Y
Wan
Shourong
S
Zheng
D002384:Catalysis; D005561:Formates / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007854:Lead / Q000737:chemistry* / Q000528:radiation effects*; D046529:Microscopy, Electron, Transmission; D010084:Oxidation-Reduction; D010777:Photochemistry; D056951:Photoelectron Spectroscopy; D045483:Rivers; D012834:Silver / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D014025:Titanium / Q000737:chemistry; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000528:radiation effects*; D018508:Water Purification / Q000379:methods*; D014881:Water Supply; D014961:X-Ray Diffraction
D005561:Formates; D014874:Water Pollutants, Chemical; C030544:formic acid; C009495:titanium dioxide; D007854:Lead; D012834:Silver; D014025:Titanium