A novel and efficient method for dechlorination of hexachlorobenzene using a sodium carbonate/glycerol system

Huang, Hai; Jiang, Jianguo; Xiao, Ye; Chen, Xuejing; Liu, Shuang

doi:10.1016/j.cej.2014.06.092

Cited by 14 publications

(11 citation statements)

References 29 publications

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“…Results showed that stronger bases, which had greater nucleophilic properties, were more effective in this process. These results contrasted with the finding of Hai et al [ 17 ]. They expressed the base solubility in the transformer oil as the main factor.…”

Section: Resultscontrasting

confidence: 99%

“…In this method, PCBs are dechlorinated by using a high-boiling-point hydrocarbon, base and metal catalyst. Bases as nucleophilic activation groups, hydrocarbons as hydrogen donors and a metal catalyst as an electron transfer surface take part in the PCB dechlorination process [ 16 , 17 ]. Various mechanisms have been proposed for BCD.…”

Section: Introductionmentioning

confidence: 99%

“…Methods in which paraffinic or aliphatic oils are used require high temperatures. However, techniques that use alcohols are more efficient and are low-temperature processes, but, besides these positive aspects, most alcohols are toxic or expensive [ 4 , 13 , 17 ]. Glycerol is a trihydric alcohol which is compatible with most chemicals, does not have harmful effects on the environment, has a high melting point, and can play the roles of hydrogen donor and solvent in the BCD process [ 17 , 25 ].…”

Section: Introductionmentioning

confidence: 99%

“…However, techniques that use alcohols are more efficient and are low-temperature processes, but, besides these positive aspects, most alcohols are toxic or expensive [ 4 , 13 , 17 ]. Glycerol is a trihydric alcohol which is compatible with most chemicals, does not have harmful effects on the environment, has a high melting point, and can play the roles of hydrogen donor and solvent in the BCD process [ 17 , 25 ]. Glycerol is expensive, but raw glycerol obtained from sources such as the biodiesel production process can be used in the BCD process [ 17 , 26 ].…”

Section: Introductionmentioning

confidence: 99%

“…Glycerol is a trihydric alcohol which is compatible with most chemicals, does not have harmful effects on the environment, has a high melting point, and can play the roles of hydrogen donor and solvent in the BCD process [ 17 , 25 ]. Glycerol is expensive, but raw glycerol obtained from sources such as the biodiesel production process can be used in the BCD process [ 17 , 26 ]. Most research concerning PCB dechlorination have been conducted on pure PCBs, or on heavily polluted transformer oils, and few studies have been reported on transformer oils contaminated with low levels of PCBs (50–500 ppm).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Base-catalysed decomposition of polychlorinated biphenyls in transformer oils by mixture of sodium hydroxide, glycerol and iron

Akhondi

Dadkhah

2018

R. Soc. open sci.

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In this research, a method based on base-catalysed decomposition (BCD) was developed using sodium hydroxide and glycerol for dechlorination of transformer oils with low levels of polychlorinated biphenyls (PCBs). PCB removal and dechlorination efficiencies were measured by gas chromatography and the silver nitrate titration method, respectively. PCB dechlorination and removal efficiencies after 4 h at 250°C and in the presence of iron were 97.4% and 99.8%, respectively. However, in the absence of iron the same efficiencies were calculated to be 79.4 and 99.7%, respectively. The dielectric loss factor of oil refined at 250°C was 0.0064 and did not meet the required standards to be reused in the transformers. However, that refined at 200°C satisfied the standards with acceptable conversion rates. Use of iron, besides increasing conversion rates, changed the mechanism of the reaction from nucleophilic substitution to a combination of hydrodechlorination and nucleophilic substitution. In the presence of iron, highly chlorinated PCBs were converted to less chlorinated PCBs, and this caused the concentration of less chlorinated PCBs to reach a peak and then decline thereafter. The production of PCB 36 confirmed this. However, in the absence of iron particles, all changes in the PCB concentration curves were downward.

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Section: Resultscontrasting

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Base-catalysed decomposition of polychlorinated biphenyls in transformer oils by mixture of sodium hydroxide, glycerol and iron

Akhondi

Dadkhah

2018

R. Soc. open sci.

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Degradation behaviors and accumulative effects of coexisting chlorobenzene congeners on the dechlorination of hexachlorobenzene in soil by nanoscale zero-valent iron

Wang

2023

Environ Geochem Health

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It is well known that many chlorinated organic pollutants can be dechlorinated by nanoscale zero-valent iron. However, in the real chlorinated organic compounds contaminated soil, high chlorinated organic pollutants and low chlorinated organic pollutants often coexist and their dechlorination behaviors are poorly known, such as hexachlorobenzene. In this work, the degradation behaviors of three coexisting chlorobenzene congeners pentachlorobenzene (PeCB), 1,2,4,5-tetrachlorobenzene (1,2,4,5-TeCB) and 1,2,4-trichlorobenzene (1,2,4-TCB) and the in uence of initial pH and reaction temperature on the dechlorination of HCB in HCB-contaminated soil by nanoscale zero-valent iron were studied. The amount and extent of accumulated coexisting chlorobenzenes was analyzed under different environmental conditions. The results indicate that nanoscale zero-valent iron can improve the degradation e ciency of high-toxic chlorinated benzenes and reduce the accumulative effects of high-toxic chlorinated benzenes on dechlorination of HCB. The accumulative effects of three coexisting chlorobenzene congeners on the dechlorination of HCB were ranked as follows: 1,2,4-TCB > 1,2,4,5-TeCB > PeCB.

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Dechlorination and conversion mechanism of trichlorobenzene as a model compound of chlorine-containing wastes by different base-catalyzed combinations

Dai

Zheng

Zhao

et al. 2019

Environ Sci Pollut Res

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A novel and efficient method for dechlorination of hexachlorobenzene using a sodium carbonate/glycerol system

Cited by 14 publications

References 29 publications

Base-catalysed decomposition of polychlorinated biphenyls in transformer oils by mixture of sodium hydroxide, glycerol and iron

Base-catalysed decomposition of polychlorinated biphenyls in transformer oils by mixture of sodium hydroxide, glycerol and iron

Degradation behaviors and accumulative effects of coexisting chlorobenzene congeners on the dechlorination of hexachlorobenzene in soil by nanoscale zero-valent iron

Dechlorination and conversion mechanism of trichlorobenzene as a model compound of chlorine-containing wastes by different base-catalyzed combinations

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