Lifetime and regeneration of immobilized titania for photocatalytic removal of aqueous hexavalent chromium.
Immobilized titania (TiO2) batch reactors reduced hexavalent chromium (Cr(VI)) in the form of potassium dichromate (K2Cr2O7) to trivalent chromium (Cr(III)) in aqueous solution at pH 3 under 171 W/m2 light intensity. The light source was a 125-W ultraviolet (UV) lamp. The Cr(VI) reduction showed zero-order kinetics (k0), while the Cr(VI) adsorption fitted with first-order kinetics (k(1st)). Adsorption capacity increased with increasing initial Cr(VI) concentration, and the area of immobilized TiO2 limited the reduction efficiency. The lifetime of fresh immobilized TiO2 was approximately 14 h. In addition, the regeneration of TiO2 with 3M sodium hydroxide (NaOH) was necessary to improve adsorption reaction.
Tuprakay
Seree
S
Environmental Engineering Department, Kasetsart University, 50 Phaholyothin Rd., Chatuchak, Bangkok 10900, Thailand. seree4008@ram1.ru.ac.th
Liengcharernsit
Winai
W
D000327:Adsorption; D002384:Catalysis; D002857:Chromium / Q000302:isolation & purification*; D009994:Osmolar Concentration; D010084:Oxidation-Reduction; D010777:Photochemistry / Q000379:methods*; D012996:Solutions / Q000737:chemistry; D014025:Titanium / Q000737:chemistry*; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
D012996:Solutions; D014874:Water Pollutants, Chemical; D014867:Water; D002857:Chromium; C009495:titanium dioxide; D014025:Titanium