Removal of trichloroethylene in groundwater with two oxidants: siderite catalyzed hydrogen peroxide and sodium persulfate

2013 ◽  
Vol 13 (1) ◽  
pp. 36-43 ◽  
Author(s):  
Weiying Huang ◽  
Fei Liu ◽  
Ni Yan ◽  
Anhuai Lu ◽  
Honghan Chen ◽  
...  

Trichloroethylene (TCE), a widely used solvent, is often determined in groundwater and is one of biologically refractory organic contaminants. The aim of the study is to use a new chemical oxidation method to degrade TCE source pollution in groundwater. Fenton-like reactions (hydrogen peroxide catalyzed by iron minerals generates hydroxyl radicals) and sodium persulfate activation (sodium persulfate activated by heat/iron minerals to produce sulfate radicals) have strong oxidative capacity to degrade a wide range of organic contaminants. In this work, hydrogen peroxide and/or sodium persulfate catalyzed by siderite (designated as STO, SO, PO systems, respectively) degrading TCE in groundwater were investigated. Removal rates of TCE in STO, SO, and PO systems were 100%, 57%, 20%, respectively. The order of TCE removal rates is in agreement with that of hydroxyl radicals generated in the systems, indicating that hydroxyl radicals play a critical role in removing TCE. No by-product except CO2, Cl− and H2O generated as final products in the STO system suggests that TCE was near completely mineralized. The results show that the STO is an effective method to treat TCE contaminated source in groundwater.

2009 ◽  
Vol 3 (1) ◽  
pp. 41-45 ◽  
Author(s):  
Olexandr Karpenko ◽  
◽  
Vira Lubenets ◽  
Elena Karpenko ◽  
Volodymyr Novikov ◽  
...  

This review covers the main agents used for in situ and ex situ chemical oxidation of organic contaminants particularly oil products, in soil and water environments. Among them there are hydrogen peroxide, permanganate salts, ozone and sodium persulfate. The fields of application, as well as benefits and disadvantages of the mentioned agents use were described.


RSC Advances ◽  
2021 ◽  
Vol 11 (57) ◽  
pp. 36257-36264
Author(s):  
Pin-Jun Lin ◽  
Chen-Hao Yeh ◽  
Jyh-Chiang Jiang

Fenton's reagent provides a method to produce active hydroxyl radicals (˙OH) for chemical oxidation by mixing iron oxide and hydrogen peroxide, which divides into homogeneous and heterogeneous Fenton's reagent.


2021 ◽  
Vol 57 (6) ◽  
pp. 87-107
Author(s):  
I.A. Bosneaga ◽  
◽  
M.C. Bologa ◽  
E.I. Agarval ◽  
◽  
...  

Modern civilization, providing economic and social progress, at the same time objectively creates – sometimes close to ideal – conditions for the spread of various infections. The catastrophic consequences of the SARS-CoV-2 pandemic clearly indicate that homo sapiens appeared to be unable to resist effectively the onslaught of the coronavirus. The purpose of this publication is an attempt to fill the gap in the development of effective methods and means for microbiological decontamination that are optimal in terms of critical parameters. Observational data indicate that a significant number of SARS-CoV-2 coronavirus infections occur by air without a direct contact with the source, including, over a long time interval. Precipitations help to cleanse the air from pollutants and viruses, reducing non-contact contamination, which additionally brings up to date the problem of optimal microbiological decontamination of the air environment and surfaces. A thermodynamic approach has been used to optimize microbiological sterilization. It is shown that irreversible chemical oxidation reactions are the shortest way to achieve sterility, and they are capable of providing high reliability of deconta-mination. It has been established that oxygen is an optimal oxidant, also from the point of view of ecology, since its reactive forms harmoniously fit into natural exchange cycles. The optimal method for obtaining reactive oxygen species for disinfection is the use of low-temperature (“cold”) plasma, which provides energy-efficient generation of oxidative reactive forms – atomic oxygen (O), ozone (O3), hydroxyl radical (·OH), hydrogen peroxide (H2O2), superoxide (O2-), and singlet oxygen O2(a1Δg). Due to a short lifetime for most of the above forms outside the plasma applicator, remote from the plasma generator objects should be sterilized with ozone (O3), the minimum lifetime of which is quite long. It has been substantiated that the microwave method of generating oxygen plasma is optimal for the energy efficient ozone production. A modular principle of generation is proposed for varying the productivity of ozone generating units over a wide range. The module has been developed on the base of an adapted serial microwave oven, in which a non-self-sustaining microwave discharge is maintained thanks to ionizers (igniters), including those based on radiating radionuclides-emitters. In case of massive contamination of surfaces, it is advisable – in addition to ozone (O3) air disinfecting – to use aqueous solutions of hydrogen peroxide (H2O2). It is essential that these reactive oxygen species for disinfecting remote from the plasma generator objects are highly efficient and, at the same time, environmentally neutral. Reliable and affordable personal protective equipment is proposed for activities in zones of increased ozone concentration. The considered optimal means of disinfection can be applicable not only in medicine, but also adapted for numerous practices in agriculture, industry, and in everyday life.


2015 ◽  
Vol 72 (10) ◽  
pp. 1869-1878 ◽  
Author(s):  
Petr Lacina ◽  
Scott Goold

In recent years, particles of iron in higher oxidation states (FeIV–VI), commonly called ferrates, have been presented theoretically as very effective oxidants. They can potentially be used for elimination of a wide range of organic and inorganic contaminants. However, so far the majority of applications have been carried out only as laboratory tests using model samples in many cases. The application of ferrates in remediation programs has so far proved to be more complicated with results failing to meet expectations. Therefore there is a necessity to consider the suitability of their use or consider their possible combination with other agents in order to reach required removal efficiencies in remediation. This study is focused on laboratory experiments using industrial groundwater leading to the proposal of a pilot field application realized as an ex-situ remediation. The combination of ferrates with hydrogen peroxide was used in this study in order to enhance the removal efficiency during pilot remediation of groundwater strongly contaminated by a wide range of organic contaminants. This combination has been shown to be very effective. During the 24-hour reaction time the majority of detected contaminants were removed by approximately 60–80%. Moreover, the unpleasant odor of the water was suppressed and suspended particles were removed by the flocculation effect of ferric sludge.


2019 ◽  
Vol 6 (12) ◽  
pp. 781-786 ◽  
Author(s):  
Xuejing Yang ◽  
Yanghua Duan ◽  
Jinling Wang ◽  
Hualin Wang ◽  
Honglai Liu ◽  
...  

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 419
Author(s):  
Moonis Ali Khan ◽  
Ramendhirran Govindasamy ◽  
Akil Ahmad ◽  
Masoom Raza Siddiqui ◽  
Shareefa Ahmed Alshareef ◽  
...  

Agglomeration and restacking can reduce graphene oxide (GO) activity in a wide range of applications. Herein, GO was synthesized by a modified Hummer’s method. To minimize restacking and agglomeration, in situ chemical oxidation polymerization was carried out to embed polyaniline (PANI) chains at the edges of GO sheets, to obtain GO-PANI nanocomposite. The GO-PANI was tested for the adsorptive removal of brilliant green (BG) from an aqueous solution through batch mode studies. Infrared (FT-IR) analysis revealed the dominance of hydroxyl and carboxylic functionalities over the GO-PANI surface. Solution pH-dependent BG uptake was observed, with maximum adsorption at pH 7, and attaining equilibrium in 30 min. The adsorption of BG onto GO-PANI was fit to the Langmuir isotherm, and pseudo-second-order kinetic models, with a maximum monolayer adsorption capacity (qm) of 142.8 mg/g. An endothermic adsorption process was observed. Mechanistically, π-π stacking interaction and electrostatic interaction played a critical role during BG adsorption on GO-PANI.


2010 ◽  
Vol 9 (3) ◽  
pp. 351-360 ◽  
Author(s):  
Abdelnaser Omran ◽  
Hamidi Abdul Aziz ◽  
Marniyanti Mamat Noor

1994 ◽  
Vol 30 (3) ◽  
pp. 73-78 ◽  
Author(s):  
O. Tünay ◽  
S. Erden ◽  
D. Orhon ◽  
I. Kabdasli

This study evaluates the characterization and treatability of 2,4-D production wastewaters. Wastewaters contain 20000-40000 mg/l COD, 17000-30000 mg/l chloride and pH is around 1.0. Chemical oxidation with hydrogen peroxide provided almost complete COD removal. The optimum conditions are 3:1 H2O2/COD oxidant dosage, 3000 mg/l Fe3+ as catalyst and pH 3. Partial oxidation at 0.5:1 H2O2//COD ratio is also effective providing 67% COD removal. A batch activated sludge system is used for biological treatability. Dilution is needed to maintain a tolerable chloride concentration which increases through COD removal. pH also increased during COD removal. 85% COD removal is obtained for the 50% dilution at an organic loading of 0.3 day‒1 on a COD basis. Completely and partially oxidized wastewaters are also treated in the activated sludge down to 30 mg/l BOD5.


1998 ◽  
Vol 38 (8-9) ◽  
pp. 213-221 ◽  
Author(s):  
Mohamed F. Hamoda ◽  
Ibrahim A. Al-Ghusain

Performance data from a pilot-plant employing the four-stage aerated submerged fixed film (ASFF) process treating domestic wastewater were analyzed to examine the organic removal rates. The process has shown high BOD removal efficiencies (> 90%) over a wide range of hydraulic loading rates (0.04 to 0.68 m3/m2·d). It could also cope with high hydraulic and organic loadings with minimal loss in efficiency due to the large amount of immobilized biomass attained. The organic (BOD and COD) removal rate was influenced by the hydraulic loadings applied, but organic removal rates of up to 104 kg BOD/ m2·d were obtained at a hydraulic loading rate of 0.68 m3/m2·d. A Semi-empirical model for the bio-oxidation of organics in the ASFF process has been formulated and rate constants were calculated based on statistical analysis of pilot-plant data. The relationships obtained are very useful for analyzing the design and performance of the ASFF process and a variety of attached growth processes.


Author(s):  
Vijaya Ramadas Mandala

The main contention of Shooting a Tiger is that hunting during the colonial period was not merely a recreational activity, but a practice intimately connected with imperial governance. The book positions shikar or hunting at the heart of colonial rule by demonstrating that, for the British in India, it served as a political, practical, and symbolic apparatus in the consolidation of power and rule during the nineteenth and early twentieth centuries. The book analyses early colonial hunting during the Company period, and then surveys different aspects of hunting during the high imperial decades in the later nineteenth and early twentieth centuries. The book draws upon an impressive array of archival material and uses a wide range of evidence to support its contentions. It examines hunting at a variety of social and ethnic levels—military, administrative, elite, princely India, Indian professional hunters, and in terms of Indian auxiliaries and (sometimes) resisters. It also deals with different geographical contexts—the plains, the mountains, north and south India. The exclusive privilege of hunting exercised by the ruling classes, following colonial forest legislation, continued to be extended to the Indian princes who played a critical role in sustaining the lavish hunts that became the hallmark of the late nineteenth-century British Raj. Hunting was also a way of life in colonial India, undertaken by officials and soldiers alike alongside their everyday duties, necessary for their mental sustenance and vital for the smooth operation of the colonial administration. There are also two final chapters on conservation, particularly the last chapter focusing on two British hunter-turned-conservationists, Jim Corbett and Colonel Richard Burton.


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