Competitive Effects of Trichloroethylene on Cr(VI) Removal by Zero-Valent Iron

Hexavalent Chromium Reduction with Zero-Valent Iron (ZVI) in Aquatic Systems

“…Junyapoon and Weerapong (2006) also reported that inorganic species, such as nickel and copper, did not interfere with the reduction of hexavalent chromium. A relatively small enhancement of Cr(VI) removal was observed by Lo et al (2005) (Lai and Lo 2008). A detrimental influence of Ca 2+ on Cr(VI) reduction was also reported by Wang et al (2010) and Liu and Lo (2011).…”

“…Studies performed by Zhou et al (2008) indicate that EDTA markedly accelerated the Cr(VI) reduction by ZVI due to the formation of complex species between EDTA and Fe(III)/Cr(III), which eliminates the possibility of forming precipitates; however, under the same conditions, the reduction of Cr(VI) by ZVI was apparently suppressed in the presence of 1,10-phenanthroline, probably because this compound can form a stable complex with Fe(II), which eliminates the redox reaction between Cr(VI) and Fe(II) (Zhou et al 2008). Lo et al (2005) observed an important drop (45%) of ZVI removal capacity when TCE was present in the solution, ascribed to the competition between TCE and Cr (VI) for electrons. On the contrary, Yang (2006) reported that although the presence of Cr(VI) affected TCE degradation, TCE did not affect Cr(VI) reduction significantly.…”

Simultaneous removal of trichloroethylene and hexavalent chromium by green synthesized agarose-Fe nanoparticles hydrogel

“…However, a remarkable decline in the removal efficiency of Cr(VI) occurred, 96.8% without TCE and 85.2% with TCE for 24 h. Meanwhile a slight decrease was observed for the removal efficiency of TCE, 97.2% without Cr(VI) and 95.3% with Cr(VI) for 24 h. Similar phenomena were documented in previous studies regarding the co-removal of Cr(VI) and TCE [16,31]. Cr(VI) and TCE are electron competitors in the redox reactions [32], and consequently their decreasing reactivity may be explained by Cr(VI) and TCE competing in their coexisting solution. The plausible reason for the varying decrement rate may be that the mechanisms for removing Cr(VI) and TCE are different.…”

Application of electrochemical depassivation in PRB systems to recovery Fe0 reactivity

“…Fe 3 O 4 was found on the surface of AW-Fe 0 . After passivated, the surface contained minerals such as α-Fe 2 O 3 /FeOOH, gFe 2 O 3 /FeOOH, d-FeOOH, Fe(OH) 3 , and Cr(OH) 3 -Cr 2 O 7 . There were no minerals detected on the surface of ElectroFe 0 .…”

“…Cr(VI) is ranked as the second most frequently found heavy metal in hazardous waste sites [3]. Cr(VI) is mutagenic, teratogenic and carcinogenic [4][5][6].…”