Auto-accelerating and auto-inhibiting phenomena in the oxidation process of organic contaminants by permanganate and manganese dioxide under acidic conditions: effects of manganese intermediates/products

RSC Advances ◽  
2016 ◽  
Vol 6 (67) ◽  
pp. 62858-62865 ◽  
Author(s):  
Bo Sun ◽  
Dandan Rao ◽  
Yuhai Sun ◽  
Xiaohong Guan
Keyword(s):  
Manganese Dioxide ◽  
Organic Contaminants ◽  
Oxidation Process ◽  
Organic Contaminant ◽  
Acidic Conditions ◽  
Presence And Absence

The accelerating and inhibiting behavior of organic contaminant oxidation by MnO4−and MnO2in the presence and absence of pyrophosphate (PP) under acidic conditions.

scholarly journals Elucidating the performance of an integrated laccase- and persulfate-assisted process for degradation of trace organic contaminants (TrOCs)

2020 ◽  
Vol 6 (4) ◽  
pp. 1069-1082
Author(s):  
Muhammad B. Asif ◽  
Jason P. van de Merwe ◽  
Frederic D. L. Leusch ◽  
Biplob K. Pramanik ◽  
William E. Price ◽  
...  
Keyword(s):  
Organic Contaminants ◽  
Oxidation Process ◽  
Organic Contaminant ◽  
Trace Organic Contaminants ◽  
Persulfate Oxidation ◽  
Contaminant Degradation ◽  
Trace Organic

This study presents the performance of an integrated laccase and persulfate oxidation process for trace organic contaminant degradation and elucidates the performance governing factors.

scholarly journals Enzyme Kinetics of Organic Contaminant Oxygenations

2020 ◽  
Vol 74 (3) ◽  
pp. 108-114
Author(s):  
Charlotte E. Bopp ◽  
Hans-Peter E. Kohler ◽  
Thomas B. Hofstetter
Keyword(s):  
Organic Contaminants ◽  
Organic Soil ◽  
Organic Contaminant ◽  
Contaminant Removal ◽  
Adaptive Responses ◽  
Water Contaminants ◽  
Kinetic Mechanisms ◽  
Substrate Hydroxylation ◽  
Catalytic Cycles ◽  
Persistent Organic Contaminants

Enzymatic oxygenations initiate biodegradation processes of many organic soil and water contaminants. Even though many biochemical aspects of oxygenation reactions are well-known, quantifying rates of oxidative contaminant removal as well as the extent of oxygenation remains a major challenge. Because enzymes use different strategies to activate O2, reactions leading to substrate oxygenation are not necessarily limiting the rate of contaminant removal. Moreover, oxygenases react along unproductive pathways without substrate metabolism leading to O2 uncoupling. Here, we identify the critical features of the catalytic cycles of selected oxygenases that determine rates and extents of biodegradation. We focus most specifically on Rieske dioxygenases, a subfamily of mononuclear non-heme ferrous iron oxygenases, because of their ability to hydroxylate unactivated aromatic structures and thus initiate the transformation of the most persistent organic contaminants. We illustrate that the rate-determining steps in their catalytic cycles range from O2 activation to substrate hydroxylation, depending on the extent of O–O cleavage that is required for generating the reactive Fe-oxygen species. The extent of O2 uncoupling, on the other hand, is highly substrate-specific and potentially modulated by adaptive responses to oxidative stress. Understanding the kinetic mechanisms of oxygenases will be key to assess organic contaminant biotransformation quantitatively.

Recent trend in visible-light photoelectrocatalytic systems for degradation of organic contaminants in water/wastewater

2018 ◽  
Vol 4 (10) ◽  
pp. 1389-1411 ◽  
Author(s):  
Moses G. Peleyeju ◽  
Omotayo A. Arotiba
Keyword(s):  
Water Treatment ◽  
Visible Light ◽  
Organic Contaminants ◽  
Advanced Oxidation Process ◽  
Oxidation Process ◽  
Recent Trend ◽  
Advanced Oxidation ◽  
Heterogeneous Photocatalysis ◽  
Treatment Technologies

Electrochemical advanced oxidation process and heterogeneous photocatalysis have received great attention in the last few years as alternative/complementary water treatment technologies.

Influence of chloride ions on organic contaminants decolorization through the Fe0-activated persulfate oxidation process: efficiency and intermediates

2019 ◽  
Vol 80 (3) ◽  
pp. 563-574 ◽  
Author(s):  
Feng Ding ◽  
Yong Xie ◽  
Tengyan Wu ◽  
Na Liu
Keyword(s):  
Organic Contaminants ◽  
Oxidation Process ◽  
Operating Cost ◽  
Oxygen Demand ◽  
Transformation Products ◽  
Chloride Ions ◽  
Process Efficiency ◽  
Persulfate Oxidation ◽  
By Products ◽  
Activated Persulfate

Abstract This study was conducted to evaluate the influence of chloride ions (Cl−) on organic contaminants decolorization by the Fe0-activated persulfate process (PS/Fe0), as well as the generation of transformation products. Orange II (OII) was chosen as the target pollution. The results indicated that Cl− influenced the OII decolorization by PS/Fe0 system, resulting in the generation of chlorine-containing by-products. OII containing Cl− solution can be efficiently decolorized by PS/Fe0 process, and the decolorization efficiencies changed depending on Cl− concentration due to the reaction between Cl− and sulfate radicals (SO4–•). The operating cost for 94% color and 64% chemical oxygen demand (COD) removal of the OII dye was estimated at 0.73 USD/m3. The chlorine-containing by-products, such as chlorobenzene, 3,5-dichloro-benzene-1,2-diol, and 2,3-dichloro-2,3-dihydro-1,4-naphthoquinone, were generated during the reaction. The results further indicated that increasing both PS concentration and temperature enhanced OII decolorization and reduced the generation of chlorine-containing intermediates. The addition of ultrasound can further decrease the generation of chlorine-containing intermediates under high-temperature conditions. The proposed pathways of decolorization of OII containing Cl− also indicated that SO4–• dominated the OII degradation, while the presence of Cl− led to the generation of chlorine-containing intermediates.

Pre-magnetization for enhancing the iron-catalyzed activation of peroxymonosulfate via accelerating the corrosion of Fe0

2019 ◽  
Vol 79 (7) ◽  
pp. 1287-1296 ◽  
Author(s):  
Yunxin Liu ◽  
Peng Zhou ◽  
Xiaowei Huo ◽  
Yang Liu ◽  
Xin Cheng ◽  
...  
Keyword(s):  
Field Gradient ◽  
Oxidation Process ◽  
Zero Valent Iron ◽  
Gradient Force ◽  
Acid Orange 7 ◽  
Lower Field ◽  
Acidic Conditions ◽  
Reactive Radicals ◽  
Better Than

Abstract Our findings proved that micron-scale zero-valent iron (mZVI) particles with pre-magnetization combined with peroxymonosulfate (PMS) can markedly enhance the removal of acid orange 7 (AO7). Investigation into the mechanism showed that PMS accelerated the corrosion of ZVI to release Fe2+ under acidic conditions, and the in-situ generated Fe2+ further activated PMS to produce SO4•− and •OH, resulting in AO7 removal. Further, the Lorentz force strengthened the convection in the solution and the field gradient force tended to move Fe2+ from a higher to a lower field gradient at the pre-magnetized ZVI (Pre-ZVI) particle surfaces, thus indicating that pre-magnetization promoted the corrosion of ZVI to release Fe2+, which resulted in the enhancement of PMS activation. Nano-scale ZVI (nZVI) was more effective than mZVI in activating PMS to degrade AO7, but the pre-magnetization effect on mZVI was better than on nZVI. AO7 removal increased with higher ZVI and PMS dosage, lower AO7 concentration, and acidic conditions (pH = 2, 3). This study helps to understand the reactive radicals-based oxidation process with application of pre-magnetized ZVI in activating PMS.

Metal inhibition on the reactivity of manganese dioxide toward organic contaminant oxidation in relation to metal adsorption and ionic potential

Chemosphere ◽  
2017 ◽  
Vol 170 ◽  
pp. 95-103 ◽  
Author(s):  
Jing Jiang ◽  
Zhuopu Wang ◽  
Yang Chen ◽  
Anfei He ◽  
Jianliang Li ◽  
...  
Keyword(s):  
Manganese Dioxide ◽  
Organic Contaminant ◽  
Metal Adsorption ◽  
Ionic Potential
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