TiO2 photocatalytic degradation of PCBs in soil-water systems containing fluoro surfactant

Huang, Qingdong; Hong, Chia Swee

doi:10.1016/s0045-6535(99)00492-0

Cited by 66 publications

(25 citation statements)

References 30 publications

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“…However, PCBs disappeared through different rates and extents in the SL and TX effluents (Figs. 4 and 5), and this suggests, as also proposed by other authors (Huang and Hong, 2000), that surfactants affected the production and the fate of free radicals in the reactor. In particular, the persistence of PCBs and the marked depletion of TOC observed in the SL containing effluents during the first 7 days of UV irradiation (Fig.…”

Section: Discussionsupporting

confidence: 73%

Sustainable decontamination of an actual‐site aged PCB‐polluted soil through a biosurfactant‐based washing followed by a photocatalytic treatment

Occulti

Roda

Berselli

et al. 2007

Biotech & Bioengineering

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A two phases process consisting of a soya lecithin (SL)-based soil washing process followed by the photocatalytic treatment of resulting effluents was developed and applied at the laboratory scale in the remediation of an actual-site soil historically contaminated by 0.65 g/kg of polychlorinated biphenyls (PCBs). Triton X-100 (TX) was employed in the same process as a control surfactant. SL and TX, both applied as 2.25 g/L aqueous solutions, displayed a comparable ability to remove PCBs from the soil. However, SL solution displayed a lower ecotoxicity, a lower ability to mobilize soil constituents and a higher soil detoxification capacity with respect to the TX one. The photocatalytic treatment resulted in marked depletions (from 50% to 70%) of total organic carbon (TOC) and PCBs initially occurring in the SL and TX contaminated effluents. Despite the ability of SL to adversely affect the rate of TOC and PCB photodegradation, higher PCB depletion and dechlorination yields along with lower increases of ecotoxicity were observed in SL-containing effluents with respect to the TX ones at the end of 15 days of treatment. The two phases process developed and tested for the first time in this study seems to have the required features to become, after a proper optimization and scale up, a challenging procedure for the sustainable remediation of actual site, poorly biotreatable PCB-contaminated soils.

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Section: Discussionsupporting

confidence: 73%

Sustainable decontamination of an actual‐site aged PCB‐polluted soil through a biosurfactant‐based washing followed by a photocatalytic treatment

Occulti

Roda

Berselli

et al. 2007

Biotech & Bioengineering

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“…As we know, PCBs were water-insoluble. So, the effects of cosolvents (Chu and Kwan 2003b, a;Lin et al 2006) and surfactants (HPCD, Brij35, and Tween80) (Huang and Hong 2000) on the photocatalytic degradation of PCB3 were examined. To our best knowledge, there has been no report about such study.…”

Section: Introductionmentioning

confidence: 99%

TiO2 photocatalytic degradation of 4-chlorobiphenyl as affected by solvents and surfactants

et al. 2012

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Purpose TiO 2 photocatalytic degradation of 4-chlorobiphenyl (PCB3) in aqueous solution under UV irradiation was investigated as affected by different environmental factors, including initial PCB3 concentration, TiO 2 content, UV intensity, H 2 O 2 concentration, cosolvents, and surfactants. Materials and methods The solution of PCB3 with TiO 2 was irradiated by medium mercury lamp. The concentration of PCB3 and intermediates was analyzed by GC-μECD and GC-MS. The values of point charge and bond length were also calculated with ChemOffice 2004 (Mopac unit). Results and discussion Photocatalysis was very effective for PCB3 removal, and the degradation kinetics were fitted with a pseudo-first order reaction model. PCB3 was efficiently degraded in the presence of acetone and acetonitrile, but was completely inhibited with other examined cosolvents. HPCD and Tween80 also inhibited the degradation rate of PCB3, while Brij35 slightly decreased the degradation rate of PCB3 at first, and then increased. The reaction mechanism occurred principally by hydroxyl radicals involving the participation of holes and superoxide anion oxidation.A possible photocatalytic degradation pathway of PCB3 was proposed based on the identified reaction intermediates as well as computer simulation. Conclusions The photocatalytic approach could be successfully applied to degrade PCB3, and cosolvents and surfactants significantly influenced its degradation kinetics.

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“…Hydroxyl radical is a powerful oxidizing species. It is highly toxic towards microorganisms and very reactive in the oxidation of toxic chemicals such as phenol and polychlorinated biphenyls (Huang and Hong, 2000;Zhang et al 2001;Dunlop et al, 2002;Wolfrum et al, 2002).…”

Section: Intorductionmentioning

confidence: 99%

Photocatalytic bactericidal activity of silver-sensitized titanium dioxide on Micrococcus lylae

Yip

Chan³

et al. 2005

J. of Wat. & Envir. Tech.

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Under UV irradiation, titanium dioxide (TiO 2 ) exhibits a strong bactericidal activity through the generation of hydroxyl radicals (•OH). Silver (Ag) sensitization is an effective way to enhance photocatalytic activity of TiO 2 . In the present study, Micrococcus lylae was used as a model bacterium to compare the bactericidal activity of Agsensitized TiO 2 (in two different Ag/TiO 2 molar ratios) and pure TiO 2 (P25). When the concentration of photocatalysts was fixed on 0.2 mg/ml with 300 rpm stirring, no obvious difference observed among the three photocatalysts. However, the Ag-sensitized photocatalysts with higher Ag/TiO 2 ratio showed better bactericidal efficiency when their concentration decreased (0.1 mg/ml) or the stirring speed increased (380 rpm). The results indicated that optimizing the phosico-chemical conditions of reaction promoted the efficiency of photocatalyst. Moreover, transmission electron microscopy (TEM) was used to observe the sub-cellular structural changes of M. lylae during photocatalytic oxidation (PCO). According to the TEM images, the disruption of cell wall occurred at a relatively long time after the cell death. The cause of cell death was the destruction of plasma membrane induced by membrane permeable •OH. These results supported that both modification on photocatalyst properties and optimization on reaction conditions enhanced the bactericidal efficiency of PCO.

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TiO2 photocatalytic degradation of PCBs in soil-water systems containing fluoro surfactant

Cited by 66 publications

References 30 publications

Sustainable decontamination of an actual‐site aged PCB‐polluted soil through a biosurfactant‐based washing followed by a photocatalytic treatment

Sustainable decontamination of an actual‐site aged PCB‐polluted soil through a biosurfactant‐based washing followed by a photocatalytic treatment

TiO2 photocatalytic degradation of 4-chlorobiphenyl as affected by solvents and surfactants

Photocatalytic bactericidal activity of silver-sensitized titanium dioxide on Micrococcus lylae

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