Activated PDS of Single-Atom-Fe(III): Nonradical Oxidation of Pollutants

Prof. Jiang et al., from (1. Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing, China; 2. University of Chinese Academy of Sciences, Beijing, China, 3. Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou, China) and their research collaboration team have reported on the single-atom Fe(III)- and nitrogen doped carbon (Fe−N−C) which can eﬃciently activate peroxydisulfate (PDS) to selectively remove some organic pollutants following an unreported nonradical pathway.

Generally, PDS is used as an oxidant for the degradation of polluted water/soil, it generates sulfate radical intermediate for the degradation pollutants, and this radical unselectively reacts with most of the substances in water/soil. PDS can be activated by base, heat, UV, low valent transition metal ions (e.g., Co^2+, Fe^2+, Cu^2+, and Ag⁺), and zero valent iron to produce a sulfate radical (SO₄^•−). All these PDS activation processes consume extensive energy or chemicals. Also, it is found that PDS is much cheaper and does not significantly reduce water pH upon addition. Sulfate radical is not preferred for purification of water. Therefore, recent research focus on the PDS activation without generating radicals is preferred to maximize its oxidation capacity for targeted pollutants.

This research work was published in Environmental Science & Technology on October 23, 2020 [1]. They find a new pathway for the degradation of pollutants without sulfate radicals, particularly, the coordinated Fe(III) is readily converted to Fe(V) through two-electron abstraction by PDS, and Fe(V) is responsible for the selective degradation of organic pollutants. The selectivity of the PDS/Fe−N−C oxidation process was examined with various pollutants, the PDS activation clearly follows a nonradical pathway. The highly dispersed Fe(III) sites on the Fe−N−C were proposed and converted to Fe(V) for pollutant degradation. This new approach is more effective than sulfate radical formation and also other reported nonradical oxidation like PDS/CuO under the same experimental conditions. This approach is also used to selectively degrade some organic pollutants through PDS activation.

Figure 1. Mechanism of nonradical oxidation of pollutants by single-atom-Fe(III) activated PDS [1].

If we use chlorinated water for purification process, chloride consumes a sulfate radical to produce a chlorine radical (Cl₂^•−), which not only reduces the oxidation potential toward pollutants but also produces hazardous chlorinated by-products [2]. Therefore, to avoid sulfate radical formation approach, a new approach is needed for water purification system with PDS. Lee et al., proposed similar approach that PDS can be attached to carbon nanotubes (CNTs) and react with phenolic compounds [3]. CNTs posses a high specific surface area (200−500 m²g⁻¹), however, their effectiveness for PDS activation still needs to be improved further.

Single-atom catalysts (SACs), with active metal sites dispersed in the single-atom state, have attracted a greater attention and wide interest in recent years for catalytic reactions. Some of the SACs were reported for the catalytic application with good efficiency. Particularly, a single cobalt-atom catalyst (Co−N−C), metal and nitrogen co-doped carbon materials [M−N−Cs (M = Fe, Co, Mn, etc.,)] and Fe(III)-doped g-C₃N has been successfully prepared, which showed good activity in peroxymonosulfate (PMS) activation. Also, the SACs have utilized its metal sites, that shows an excellent catalytic activity, structural stability and becomes a frontier in catalysis, especially for hydrogen evolution, oxygen reduction, and CO₂ conversion. These results inspired us to search for an appropriate M−N−C to activate for the cheaper PDS.

As an ﬁrst attempt, Jiang et al. and his team have apply a single atom Fe(III) for eﬀective PDS activation without generating radicals. Further, they have prepared single atom site of Fe−N−C characterized by Aberration-corrected high-angle annular dark-ﬁeld scanning transmission electron microscopy, X-ray adsorption spectra (XAS) including X-ray adsorption near-edge structure (XANES) and extended X-ray adsorption ﬁne structure (EXAFS).

Oxidation of pollutants was tested with batch reactions. They used phenol, bisphenol A, chlorophenols, sulfamethoxazole, atrazine, benzoic acid, EDTA, p-chloro benzoic acid, and benzothiazole to test the selectivity of the PDS/Fe−N−C-coupled oxidation. Further, they observed that all the compounds were degraded in this process except for benzothiazole, p-chloro benzoic acid, and benzoic acid. Benzoic acid and p-chloro benzoic acid have low reactivity possibly because of no substituent group existing at their α-C, which is not favorable for Fe(V) attack. Because of the high stability of the thiazole ring, benzothiazole was barely degraded here. The selectivity also shows that PDS/Fe−N−C has lower oxidation power as compared with sulfate and hydroxyl radicals.

Important points regarding environmental significance of this research work:

The single-atom Fe(III) material, Fe−N−C, can eﬃciently activate PDS to degrade some organic pollutants.
The PDS activation follows a nonradical pathway with Fe(V) as the possible intermediate oxidant for pollutant removal.
This reported SACs were used for the remediation of polluted groundwater and soil, and the treatment of drinking water and some industrial wastewater without any toxicity.
A low dosage of the Fe−N−C can achieve relatively high eﬃciency in pollutant degradation.

Our SNB team recommended this research article to enrich our viewer’s knowledge to know about the single-atom Fe(III)- and nitrogen doped carbon (Fe−N−C) can eﬃciently activate PDS to selectively remove some organic pollutants followed with an unreported nonradical pathway. The research studies showed that PDS can be activated while not generating radicals, that is, the pollutants can be degraded just through electron transfer to PDS. Hence, the future work is needed to develop an low cost approaches to obtain a large amount of single-atom Fe−N−C materials (e.g., through pyrolysis of biosolids) and to investigate the selectivity of the PDS/Fe−N−C oxidation and the transformation pathway of pollutants.

References

N. Jiang, et al., Environ. Sci. Technol. (2020) https://dx.doi.org/10.1021/acs.est.0c04867.
T. Zhang, et al., Environ. Sci. Technol. 48, 5868 (2014).
H. Lee, et al., Chem. Eng. J. 266, 28 (2015).

Blog Written By

Dr. A. S. Ganeshraja

Assistant Professor

National College, Tiruchirappalli

Tamil Nadu, India

Author Profile

Editors

Dr. K. Rajkumar

Dr. S. Chandrasekar

Reviewers

Dr. Y. Sasikumar

Dr. S. Thirumurugan

Dr. K. Vaithinathan

Comments

PROSPECTS ON PHOTOBIOREFINERY

Very recently, Prof. Dr. K. Faungnawakij and his research group have summarized a mini review report on an emerging renewable technique of Photobiorefinery . This is one of the beyond technique of Artificial Photosynthesis (AP) [1] . Despite great promises, AP technologies for solar H2 production and CO2 reduction are far uncompetitive to other promising technologies at the current stage . However, despite an enormous effort, time, and budget paid on AP-related researches throughout several decades, AP technologies have struggled to strive beyond laboratory demonstration except a very few exceptions [2] . This bitter reality makes the translation of this excellent science to practical application questionable [3] . Technoeconomic analysis shows that without achieving the aggressive technology targets, this technology will not be commercially viable. This has directed the research community towards the development of highly efficient yet expensive devices. While tremendous p...

Impact on Climate and Land Use Changes Around Ganga River

In India, Ganga is the largest river and also famous spiritual river, in meantime pollution issue in Ganga river is considered to be one of the most discussed topics on river water quality in the past decades . The river gets s everely polluted with untreated industrial and human wastes, and the river crossed around 11 states in India and provides water for about 40% of India's population, approximately 500 million people, we couldn’t find more than any other river in the world [ 1, 2 ]. Central Pollution Control Board (CPCB) has mentioned that 764 grossly polluting industries were discharging into the Ganga river, 487 industries are from the Kanpur region. Therefore, the Kanpur region was treated as the main polluted spot and immediate action should be taken for further recovery of water quality. The Kanpur region is one of the most important industrialized place in India. It is the most polluted stretch of the Ganga River, because of its excessive pollutant discharge from the i...

Electric Vehicle: Public Health and Climate Benefits

A research team led by Daniel Peters at Northwestern University has investigated that if we introducing electrifying vehicles in the streets of the United States could annually prevent hundreds-to-thousands of premature accidental deaths.This work highlights the potential of a synergistic solution to reduce CO 2 emissions by hundreds to millions of tons annually. The estimate of economic damages induced by introducing electrifying vehicles (EV) adoption is substantial. With current infrastructure, about 25% of electrifying vehicles adoption in the US can save approximately $16.8 billion annually, has been told in the study entitled"Public Health and Climate Benefits and Trade offs of U.S. Vehicle Electrification," in GeoHealth on 13 th August 2020 [1] . Vehicle electrification in the United States could prevent hundreds to thousands of premature deaths annually while reducing carbon emissions by hundreds of millions of tons. This highlights the potential of co-beneficial...

Efficient Bio-Diesel Synthesis: Reusable Magnetic Catalysis

Prof. Anping Wang et al., with his research collaborative team from china ( 1. Guizhou University, China; and 2. Guizhou Normal University, China) and India (National Chemical Laboratory, India) have reviewed the research over views on the preparation methods, physicochemical properties, stabilization/functionalization, and the catalytic applications of magnetic materials, including magnetic acids, bases, enzymes, and acid-base bifunctional materials for the synthesis of bio-diesel. Here, we discuss only the preparation of efficient bio-diesel with merits and applications of magnetic nanocatalyst for the bio-diesel preparation . Bio-diesel products are mainly attain from bio mass feed stocks, which gives more attention in the biorefinery research affairs [1]. A green way of renewable liquid biofuels are emergency required one in present atmosphere. Among the various classes, best one is renewable diesel fuel, the chemical content of long-chain fatty acid methyl ester (FAME) or ethy...

Plasmonic Gold Nanoparticles as Designing Caps

Plasmonic nanomaterials have attracted significant interest because of its wide variety of applications such as sensing, energy conversion, photothermal therapy etc. Among the various plasmonic inorganic metals (Ag, Cu, Al, and Au) Au shows the excellent biocompatibility, chemical stability, and rich surface functionality. It can be seen that some new approaches have include the construction of metal shells on dielectric nanoparticles, and the control of island growth on nanoparticles and nanorods over the design of narrow gaps via nanoplates or nanoshells. Also, the conventional modulation of plasmonics via the control of shape, size and the aspect ratio of nanomaterials. The structural control have also arises from the active surface growth. As a result, the dynamic competition between ligand absorption and metal deposition occurs [ 1 ]. The properties of plasmonic nanostructures are highly dependent on its surface morphology, however, there are a very few methods for a...

Scientific Research Focus on “To End Hunger”

According to the Food and Agriculture Organization of the United Nations (FAO UN), Hunger Report, Ending hunger is a major objective of the United Nations’ (UN) Sustainable Development Goals (SDG), hunger is the term used to define periods when populations are experiencing severe food insecurity - means that they go for entire days without eating due to lack of money, lack of access to food, or other resources [ 1 ]. Hunger is strongly interconnected with poverty, and it involves interactions among an array of social, political, demographic, and societal factors. An attention is must in the following topics to put an end card for poor hunger: Global Hunger Index (GHI). World Food Program’s 2020. Global Report on Food Crises. Smallholder-farming. Ceres2030. The two main international institutions are the International Institute for Sustainable Development (IISD) and the International Food Policy Research Institute (IFPRI) , joined forces to estimate what it would cost to ...

New Smart Face Mask: Lab-on-Mask

Face masks have become a part of many people's everyday wardrobe due to the coronavirus pandemic. Researchers, designers, and everyday people have shown their imagination and creativity by turning face masks into art projects and expressions of identity. While the work on the COVID-19 vaccine is still in progress, people have advised to maintain social distance, personal hygiene in public places, in addition, to mandatorily wear face masks all-the-time outside of the home. Coronavirus disease (COVID-19) is an infectious disease caused by a newly discovered coronavirus. Most of our peoples are infected due to COVID-19, they will experience mild to moderate respiratory illness and recover without requiring special treatment. The coronavirus spreads primarily through droplets of saliva or discharge from the nose when an infected person coughs or sneezes, speaks, and sings [ 1 ]. Older people and those with underlying medical problems like cardiovascular dise...

Eco-Friendly Smart Green Cities

In the world, 55% of the population lives in cities and is expected to increase to 68% by 2050. Cities are identified by their stunning skyscrapers which turn out to consume 75% of total power consumption. It is most important to emphasize energy efficiency and nonpolluting building materials used for construction. These days buildings have different types of designs to satisfy the specific requirements of its purpose and people who live and work in them. As time goes, with growing technology, the building constructions need to be designed and function with real-time natural environments with land, water and solar energy [ 1 ] . Thus sustainable practices and materials for building design and function are necessary for a sustainable future. According to the world green building council, a building in its architecture, construction or function, eliminates negative impacts and generates positive impacts on our environment is referred as a green building. Green buildings are mostly d...

Giant Spontaneous Hall Effect Without a Magnet

Surprising phenomenon in the solid state physics was “ The Hall effect, which requires normally magnetic fields, can also be generated completely in a different way by without the magnet to give an extreme strength ” – Published by Sami Dzsabera et al., in the Proceedings of the National Academy of Sciences, on 19 th February 2021. Weyl–Kondo semimetal have been discovered recently, the three-dimensional (3D) Dirac cones that describes with massless relativistic quasiparticles, which was stabilized by breaking via either time-reversal symmetry (TRS) or inversion symmetry (IS). Sami Dzsabera et al., have reported the discovery of a giant spontaneous Hall effect in 3D materials, which have not only identifies an ideal technique. However, it will demonstrates a strong correlations that can drive extreme topological responses, which we can expect to trigger for future work. Further, they reported that the giant spontaneous Hall effect of semimetal seems to be th...

Detection of Cancer via New Nano-Based Imaging Agents

New imaging agents were developed by physicians to detect cancer with better specificity and sensitivity. Further, they have the potential to significantly improve patient outcomes. It could offer enhanced premature cancer cells detection during routine screening and help the surgeons to identify tumor margins for surgical resection. Figure 1. In vivo visualization of 200 nm G8-liposomes imaged following intravenous injection [ 1 ]. Notice the bright accumulation and homogenous appearance of liposomes encapsulated with G8 dye (green). The vasculature region depicted here is of the mouse ear where real time flow video was taken at 30 fps. Scale bar represents 50 μm. Recently, Helen R. Salinas et al ., has evaluated the optical properties from a colorful class of pigments and dyes that humans routinely encounter [ 1 ]. These selective dyes and pigments are approved by Food and Drug Administration (FDA) which have utilized for the coloring of foods, drugs, and cosmetics. The authors...

Search This Blog