Combined photooxidation/photoreduction using TiO{sub 2} photocatalysts to treat organic/inorganic metal-laden wastewaters
Titanium dioxide (TiO{sub 2}) colloids prepared from titanium chloride (TiCl{sub 4}) were used as photocatalysts in the experiments. Cysteine was selected as the model derivative for the surface modification of the TiO{sub 2} nanoparticles. Testing of TiO{sub 2} photocatalysts conducted in the absence of organic compounds demonstrated that adsorption of lead ions occurred in the system with either untreated (virgin) or treated (modified using cysteine) TiO{sub 2} photocatalysts. Adsorption rates of the metal ions in the systems that used treated TiO{sub 2} photocatalysts were about three times faster than those where untreated TiO{sub 2} photocatalysts were used. Lead ion concentrations in the irradiated solutions decreased as the UV irradiation time increased; greater metal removals were achieved at longer irradiation times. The rate of decreasing lead ion concentrations in the system that used treated TiO{sub 2} photocatalysts was about two to three times faster than that in the system using untreated TiO{sub 2} photocatalysts. Experiments were also performed in which organic compounds (naphthalene or phenol) and heavy metals (Pb{sup 2+}) were simultaneously treated with TiO{sub 2} photocatalysts. The presence of lead ions did not interfere with the photo-degradation of the selected organic compounds from solution. The presence of phenol compound appeared not to affect the photoreduction of lead ions, while addition of naphthalene compound resulted in a lag-time effect on the photoreduction of lead ions from solution. All of the experimental results showed that the cysteine-modified TiO{sub 2} resulted in faster and more effective removal than that for the untreated TiO{sub 2} system. This technique has resulted in the simultaneous photocatalytic removal/recovery of organic and inorganic compounds in the system.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 28268
- Report Number(s):
- ANL/ES/CP-85677; CONF-950216-61; ON: DE95008268; TRN: AHC29510%%73
- Resource Relation:
- Conference: Waste management `95, Tucson, AZ (United States), 26 Feb - 2 Mar 1995; Other Information: PBD: [1995]
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
TITANIUM OXIDES
CATALYTIC EFFECTS
LEAD
REMOVAL
NAPHTHALENE
PHENOL
WASTE WATER
WATER TREATMENT
CYSTEINE
ADDITIVES
ULTRAVIOLET RADIATION
OXIDATION
PHOTOCHEMICAL REACTIONS
REDOX REACTIONS
SORPTIVE PROPERTIES
EXPERIMENTAL DATA