You are here:
THE PHOTOCATALYTIC OXIDATION OF LOW CONCENTRATION MTBE ON TITANIUM DIOXIDE FROM GROUNDWATER IN A FALLING FILM REACTOR
Citation:
Almquist, C. B., E SahleDemessie*, J Enriquez*, AND P. Biswas. THE PHOTOCATALYTIC OXIDATION OF LOW CONCENTRATION MTBE ON TITANIUM DIOXIDE FROM GROUNDWATER IN A FALLING FILM REACTOR. Environmental Progress & Sustainable Energy. American Society of Chemical Engineering (AIChE), New York, NY, 22(1):14-23, (2003).
Description:
This study focuses on three objectives: 1) to determine the feasibility of using a falling-film slurry photocatalytic reactor for the degradation of MTBE in water, 2) to assess the feasibility of MTBE photo-oxidation on TiO2 at low initial MTBE concentrations (<10 mg/L), and 3) to compare the effectiveness of MTBE photo-oxidation on TiO2 in synthetically-contaminated wate and in actual MTBE-contaminated groundwater samples. The MTBE degradation rates observed in a laminar falling film reactor for synthetic samples, with concentrations ranged from 50 ug/L to 10 mg/L, were high, achieving nearly complete (99+%) degradation of 1 mg/L MTBE and its by-products in less than 90minutes. The calculated single-pass conversions were as high as 60%, corresponding to residence times of approximately 5 seconds in the falling film reactor. The observed degradation products of MTBE oxidation were predominantly tert-butyl alcohol and tert-butyl formate. However, tests conducted using ground samples showed significantly reduced photoactivity of TiO2 towards the degradation of MTBE. The reduced rate of MTBE photo-oxidation on TiO2 is probably due to the competition of dissolved metal and chloride ions for electron acceptor sites and the possible inhibition of TiO2 surface by the presence of aromatic oranic species (benzene, toluene, ethylbenzene, and xylenes) in the groundwater samples. Reducing the pH of the groundwater samples or adding H2O2 increased the MTBe degradation rate significantly.