Azo dye decolorization by ZVI under circum-neutral pH conditions and the characterization of ZVI corrosion products

Khan, Abuzar; Prabhu, Subbaiah Muthu; Park, Jaeseon; Lee, Woojin; Chon, Chul Min; Ahn, Joo Sung; Lee, Giehyeon

doi:10.1016/j.jiec.2016.11.017

Cited by 27 publications

(11 citation statements)

References 40 publications

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“…They have found that over 75% of the dye was eliminated in 250 min at pH 4, while removal dropped down to 54% at pH 10. It was concluded that degradation was enhanced in acidic and circumneutral conditions compared to alkaline ones, presumably because of higher ZVI corrosion and lower surface passivation at the lower pH values [78]. These results are in agreement with those of Harada et al [47], who studied the effect of the solution pH (3–7) on the performance of micro- and nano-sized ZVI in wastewater treatment.…”

Section: Effect Of Ph On Zvi Performancesupporting

confidence: 84%

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Effect of pH on Zero Valent Iron Performance in Heterogeneous Fenton and Fenton-Like Processes: A Review

2018

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Heterogeneous Fenton processes with solid catalysts have gained much attention for water and wastewater treatment in recent years. In the field of solid catalysts, zero valent iron (ZVI) is among the most applicable due to its stability, activity, pollutant degradation properties and environmental friendliness. The main limitation in the use of ZVI in heterogeneous Fenton systems is due to its deactivation in neutral and alkaline conditions, and Fenton-like processes have been developed to overcome this difficulty. In this review, the effect of solution pH on the ZVI-Fenton performance is discussed. In addition, the pH trend of ZVI efficiency towards contaminants removal is also considered in oxic solutions (i.e., in the presence of dissolved O2 but without H2O2), as well as in magnetic-field assisted Fenton, sono-Fenton, photo-Fenton and microwave-Fenton processes at different pH values. The comparison of the effect of pH on ZVI performance, taking into account both heterogeneous Fenton and different Fenton-like processes, can guide future studies for developing ZVI applications in water and wastewater treatment.

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Section: Effect Of Ph On Zvi Performancesupporting

confidence: 84%

“…By increasing the solution pH to around 6, the removal efficiency was reduced to 15% in 40 min. Khan et al have studied the effect of the initial pH (4–10) on azo-dye removal by ZVI-Fenton [78]. They have found that over 75% of the dye was eliminated in 250 min at pH 4, while removal dropped down to 54% at pH 10.…”

Section: Effect Of Ph On Zvi Performancementioning

confidence: 99%

Effect of pH on Zero Valent Iron Performance in Heterogeneous Fenton and Fenton-Like Processes: A Review

2018

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“…Overall, pyrite accelerated the removal of dyes by ZVI, and the quantitative enhancement on the reaction rate was estimated by fitting the kinetic data in the initial reaction stage (before 40 min) with the pseudo‐first‐order model. The k obs (reaction rate constant) values for dye removal by ZVI alone obtained in this study (1~5 × 10 −3 min −1 ) are comparable to that reported previously by Khan et al ., in which a dosage of 1 g/L ZVI powder (< 63 μm particle size) was used. Figure 1(d) shows that the k obs values for removal of Orange II increased with the increasing pyrite dosage.…”

Section: Resultsmentioning

confidence: 96%

Pyrite enhanced the reactivity of zero‐valent iron for reductive removal of dyes

Chen

Han

et al. 2020

J of Chemical Tech & Biotech

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BACKGROUND Zero‐valent iron (ZVI) is an environmentally friendly and cost‐efficient material for the removal of contaminants. However, its application is challenged by problems such as surface passivation and pH increase in the reaction media. As a potential solution for this problem, pyrite, a waste of the mining industry, was used together with ZVI for reductive removal of azo dyes. RESULTS In comparison with ZVI alone, the ZVI/pyrite mixture showed dramatically enhanced efficiency and reusability for dye removal, although pyrite itself can hardly remove dyes. The reaction rate constant kobs for the removal of Orange II at the initial pH (pH0) of 7.0 was enhanced 9.4‐ to 28.0‐fold by using the mixture at a pyrite/ZVI mass ratio ranging from 1 to 4, respectively. The mechanism studies indicate that pyrite not only helped produce more iron(II) by facilitating iron corrosion and the iron(II)/iron(III) cycle in the mixed system, but also activated the ZVI surface by in situ sulfidation. The high reactivity of the adsorbed iron(II) in the mixed system significantly contributed to dye removal, especially at the alkalescent pH. CONCLUSION Pyrite accelerated the reductive removal of dyes by ZVI, through inhibiting its surface passivation and suppressing the pH increase in the reaction media. Therefore, this research proposes a facile method for enhancing the reactivity and applicability of ZVI in environmental remediation. © 2020 Society of Chemical Industry

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“…As indicated in Figure 3 c, the k app value in the PDS system decreased from 0.063 to 0.007 min −1 with increasing pH from 3 to 7. At acidic pH, the ZVI corrosion rate is higher, leading to increased Fe 2+ liberation and ROS generation [ 23 ]. As pH increases to 7, the ZVI corrosion rate decreases (less Fe 2+ liberation), inhibiting the ROS generation rate.…”

Section: Resultsmentioning

confidence: 99%

Systematic Performance Comparison of Fe3+/Fe0/Peroxymonosulfate and Fe3+/Fe0/Peroxydisulfate Systems for Organics Removal

Yeek-Chia

Mohamad

et al. 2021

Materials

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Activated zero-valent iron (Ac-ZVI) coupled with Fe3+ was employed to activate peroxymonosulfate (PMS) and peroxydisulfate (PDS) for acid orange 7 (AO7) removal. Fe3+ was used to promote Fe2+ liberation from Ac-ZVI as an active species for reactive oxygen species (ROS) generation. The factors affecting AO7 degradation, namely, the Ac-ZVI:Fe3+ ratio, PMS/PDS dosage, and pH, were compared. In both PMS and PDS systems, the AO7 degradation rate increased gradually with increasing Fe3+ concentration at fixed Ac-ZVI loading due to the Fe3+-promoted liberation of Fe2+ from Ac-ZVI. The AO7 degradation rate increased with increasing PMS/PDS dosage due to the greater amount of ROS generated. The degradation rate in the PDS system decreased while the degradation rate in the PMS system increased with increasing pH due to the difference in the PDS and PMS activation mechanisms. On the basis of the radical scavenging study, sulfate radical was identified as the dominant ROS in both systems. The physicochemical properties of pristine and used Ac-ZVI were characterized, indicating that the used Ac-ZVI had an increased BET specific surface area due to the formation of Fe2O3 nanoparticles during PMS/PDS activation. Nevertheless, both systems displayed good reusability and stability for at least three cycles, indicating that the systems are promising for pollutant removal.

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Azo dye decolorization by ZVI under circum-neutral pH conditions and the characterization of ZVI corrosion products

Cited by 27 publications

References 40 publications

Effect of pH on Zero Valent Iron Performance in Heterogeneous Fenton and Fenton-Like Processes: A Review

Effect of pH on Zero Valent Iron Performance in Heterogeneous Fenton and Fenton-Like Processes: A Review

Pyrite enhanced the reactivity of zero‐valent iron for reductive removal of dyes

Systematic Performance Comparison of Fe3+/Fe0/Peroxymonosulfate and Fe3+/Fe0/Peroxydisulfate Systems for Organics Removal

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