Treatment of wastewater containing Cu(II)-EDTA using immobilized TiO2/solar light.
The photocatalytic oxidation (PCO) of Cu(II)-ethylene diamine tetra-acetic acid (EDTA), employing immobilized TiO2, under natural sunlight rather than artificial UV light conditions, was investigated at a latitude 38 degrees. The immobilized TiO2 film was prepared using a sol gel process, the crystalline structure of which was identified, by X-ray diffraction analysis, as a mixture of the rutile and anatase forms. The PCO of Cu(II)-EDTA was examined in a circulating reactor with 20 L of 10(-4) M Cu(II)-EDTA and synthetic and real wastewaters at pH 4 and 6.5, respectively. The removals of both Cu(II) and DOC were initially relatively rapid, but slowed as the reaction proceeded and generally followed first-order kinetics. The rate constants for the removal of Cu(II) and DOC were 1.1 x 10(-3) and 1.6 x 10(-3) min-1, respectively. The efficiency of the PCO in the decomplexation of Cu(II)-EDTA increased with increasing H2O2 dose using both the synthetic and real wastewaters. Therefore, we suggest the PCO process using the solar/immobilized TiO2 system, with addition of H2O2 as well as filtration for the removal of suspended solids, can be effectively applied to the treatment of Cu(II)-EDTA containing real wastewater.
Cho
Il-Hyoung
IH
Dept of Environmental Eng, Strategy Engineering Corporation, Anyang Gyeonggi, Korea.
Lee
Nae-Hyun
NH
Yang
Jae-Kyu
JK
Lee
Seung-Mok
SM
D004492:Edetic Acid / Q000737:chemistry* / Q000302:isolation & purification; D006861:Hydrogen Peroxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D010777:Photochemistry / Q000295:instrumentation / Q000379:methods; D015203:Reproducibility of Results; D013472:Sunlight; D014025:Titanium / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*
C009495:titanium dioxide; D004492:Edetic Acid; D006861:Hydrogen Peroxide; D014025:Titanium