In order to recover the lanthanum element and produce a photocatalysts which can be excited under visible light, this study tried to get phosphor powders from the spent fluorescent lamps, then using Acid Leaching Method to obtain Lanthanum ionic solution. The modify TiO2 photocatalytic was then produced by utilizing residue and commercial Lanthanum, followed by testing and comparing their photocatalytic result under visible light. The results showed that when phosphor powder-to-nitric acid ratio is 1:3, 157.5mg/L of Lanthanum could be obtained, which is the best condition on extraction. In order to enhance concentration of Lanthanum from extract, several different kind of acid were used to perform the continuous acid leaching experiment. The experiment results showed that 362mg/L of Lanthanum could be obtained while 1M HNO3 , 5M HNO3 and 5M HCl were used to leach for 6hr. The results for photocatalytic experiment under visible light showed that the 78% degradation efficiency could be obtained for 3% commercial Lanthanum doping with TiO2; for the recovered Lanthanum, the best degradation efficiency is 93.2% when 1% of it doping with TiO2. If the amount of Lanthanum for doping with TiO2 was increased, the degradation efficiency will decrease. When the recovered Lanthanum is doped over 3wt% with TiO2, the degradation efficiency will lower than commercial one. This result showed that the recovered Lanthanum contains many impurities which will be also doped on TiO2, so the degradation efficiency was decreasing. Finally, the reuse performance for recovered Lanthanum was tested and showed that it could be reused for 11 times. In second year, the recovered Lanthanum doping with TiO2 will be coated on functional materials and then hen using it to test the degradation efficiency of NOx in atmospheric and formaldehyde in indoor air.

Photocatalysis, Phosphors powder, La-TiO2