Role of reactive oxygen species in the dechlorination of trichloroethene and 1.1.1-trichloroethane in aqueous phase in UV/TiO 2 systems

Ndong, Landry Biyoghe Bi; Gu, Xiaoli; Lu, Shuguang; Ibondou, Murielle Primaelle; Qiu, Zhaofu; Sui, Qian; Mbadinga, Serge Maurice; Mu, Bo‐Zhong

doi:10.1016/j.ces.2014.11.034

Cited by 21 publications

(2 citation statements)

References 43 publications

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“…Adsorption of O 2 is associated with an electron transfer from the surface defects and results in the formation of superoxide anion. , This reactive oxygen species presents a relatively low reactivity toward organic compound oxidation, because of its disproportionation to molecular oxygen and H 2 O 2 . However, O 2 •– plays an important role in the oxidation processes conducted in acidic and neutral solutions . O 2 •– participates also in early stages of degradation of phenolic compounds, while hydroxyl radicals react with the formed intermediates leading to their complete mineralization …”

Section: Introductionmentioning

confidence: 99%

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On Oxygen Activation at Rutile- and Anatase-TiO₂

et al. 2015

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The rutile form of titanium dioxide (r-TiO 2 ) usually shows a photocatalytic activity lower than that of anatase-TiO 2 (a-TiO 2 ). Nevertheless, there are numerous examples of sometimes unexpectedly high activity of r-TiO 2 . This material may appear to be particularly useful when a noncomplete and selective photocatalytic oxidation of organic substrates is required. On the basis of literature examples and our own studies, we compare the photocatalytic activities of r-TiO 2 , a-TiO 2 , and r-TiO 2 /a-TiO 2 composites. Because of a significantly better oxygen adsorption at the surface of r-TiO 2 and a lower redox potential of the excited electron, more efficient O 2•− production takes place at the surface of rutile. As a consequence, generation of 1 O 2 (involving O 2 reduction and the subsequent oxidation of superoxide) and reduction of H 2 O 2 to OH − and HO • are also favored with this material. Therefore, r-TiO 2 can be considered to be a particularly good photocatalyst for activation of molecular oxygen. On the other hand, a-TiO 2 appears to be a stronger oxidant. In its presence, efficient HO • generation (the result of water or surface hydroxyl group oxidation) and oxidation of H 2 O 2 to O 2•− are observed.

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Section: Introductionmentioning

confidence: 99%

“…•− plays an important role in the oxidation processes conducted in acidic and neutral solutions. 8 O 2…”

Section: ■ Introductionmentioning

confidence: 99%

On Oxygen Activation at Rutile- and Anatase-TiO₂

et al. 2015

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Combination of zero-valent iron and anaerobic microorganisms immobilized in luffa sponge for degrading 1,1,1-trichloroethane and the relevant microbial community analysis

Wang

2016

Appl Microbiol Biotechnol

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1,1,1-Trichloroethane (1,1,1-TCA), a dense non-aqueous phase liquid (DNAPL), is relatively slow to remediate naturally; combination of zero-valent iron and immobilized microorganism is a potential means to accelerate DNAPL biodegradation. We first adopted high density luffa sponge (HDLS) as immobilized microorganism carrier. The experimental results demonstrated that (1) the supernatant liquid microorganisms were the optimal immobilized microorganisms for HDLS and (2) the combination of zero-valent iron and immobilized microorganisms accelerated 1,1,1-TCA transformation. Furthermore, in the long-term remediation process, anaerobic microorganisms produced reductant HS which was beneficial to zero-valent iron PRBs. Through further study of the microbial community, we found that majority of the sulfate-reducing bacteria (SRB) perfectly adapted to the process of 1,1,1-TCA co-metabolism dechlorination. Desulfobulbus and Desulfococcus potentially were the special SRB that contributed significantly to TCA co-metabolism. Additionally, 1,1,1-TCA induced the generation of new SRB and stimulated the growth of majority of dominating methanogens. The results indicated that they played a constructive role in accelerating the dechlorination of 1,1,1-TCA, reduction of sulfate, and improving the production of CH. Consequently, combination of zero-valent iron and immobilized microorganisms for remediating groundwater by contaminated 1,1,1-TCA is a sustainable and green remediation technology. Especially for groundwater of SO type contaminated by 1,1,1-TCA, in the long-term course of combination degradation, cyclic utilization of HS to prolong the service life of zero-valent iron PRBs. H and CH generated to capture as potential energy resource. Based on this, a tentative reaction mechanism for Fe biodegradation of 1,1,1-TCA was proposed.

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Effects of biological clogging on 1,1,1-TCA and its intermediates distribution and fate in heterogeneous saturated bio-augmented permeable reactive barriers

Wang

2018

Environ Sci Pollut Res

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Biological clogging in porous media was an important concern in the design of bio-augmented permeable reactive barriers (Bio-PRBs) that were used to remediate groundwater with dense non-aqueous phase liquids (DNAPLs). Here, we used laboratory sandbox experiments to develop and calibrate reactive transport models (C1 and C2) simulating 1,1,1-trichloroethane (1,1,1-TCA) change in heterogeneous saturated porous media. The routine (1,1,1-TCA chain kinetic reactions) and subroutine (the relationship between hydraulic conductivity (K) and time (t)) were included in the model computer code. The simulation results suggested that the model C1 had the applicability for simulating contaminant transport and fate in bio-augmented flow field. By using the model C1 which was suitable for constant K condition, the performance of different types of Bio-PRBs was evaluated, and the regularity of contaminants chain kinetic reactions in different heterogeneous saturated porous media was obtained. The results demonstrated that Bio-PRBs in immobilized microorganism (IM) protocol were more superior to Bio-PRBs in free microorganism (FM) protocol. In addition, by using the model C2 (updated model C1) which was suitable for decreasing K condition, the different and optimized regularity of contaminants transport and transformation was obtained. The results showed that microbial growth which further decreased K was beneficial to preventing the transport of contaminants and accelerating the transformation of contaminants. However, the negative effects of biological clogging on hydraulic conductivity and relative hydraulic conductivity ratio in FM Bio-PRBs were significantly stronger than that in IM Bio-PRBs. Deploying IM Bio-PRBs for groundwater remediation would be much more efficient and meet the design criteria. The research work had guiding significance to engineering and provided consultation for designing and optimizing Bio-PRBs system. To make the design and optimization of Bio-PRBs system convenient, it was very essential to choose the suitable mathematical model (C1 or C2).

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Role of reactive oxygen species in the dechlorination of trichloroethene and 1.1.1-trichloroethane in aqueous phase in UV/TiO 2 systems

Cited by 21 publications

References 43 publications

On Oxygen Activation at Rutile- and Anatase-TiO₂

On Oxygen Activation at Rutile- and Anatase-TiO₂

Combination of zero-valent iron and anaerobic microorganisms immobilized in luffa sponge for degrading 1,1,1-trichloroethane and the relevant microbial community analysis

Effects of biological clogging on 1,1,1-TCA and its intermediates distribution and fate in heterogeneous saturated bio-augmented permeable reactive barriers

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Role of reactive oxygen species in the dechlorination of trichloroethene and 1.1.1-trichloroethane in aqueous phase in UV/TiO 2 systems

Cited by 21 publications

References 43 publications

On Oxygen Activation at Rutile- and Anatase-TiO2

On Oxygen Activation at Rutile- and Anatase-TiO2

Combination of zero-valent iron and anaerobic microorganisms immobilized in luffa sponge for degrading 1,1,1-trichloroethane and the relevant microbial community analysis

Effects of biological clogging on 1,1,1-TCA and its intermediates distribution and fate in heterogeneous saturated bio-augmented permeable reactive barriers

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On Oxygen Activation at Rutile- and Anatase-TiO₂

On Oxygen Activation at Rutile- and Anatase-TiO₂