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Treatment of Metalworking Effluent: Chemical Precipitation, Advanced Oxidative Processes and Biological Treatments
Published in Ram Naresh Bharagava, Sandhya Mishra, Ganesh Dattatraya Saratale, Rijuta Ganesh Saratale, Luiz Fernando Romanholo Ferreira, Bioremediation, 2022
Daniel Delgado Queissada, Jesiel Alves da Silva, Vanessa Cruz dos Santos, Iraí Tadeu Ferreira de Resende, Débora da Silva Vilar, Ram Naresh Bharagava, Luiz Fernando Romanholo Ferreira
The oxidation of ferrous ions to ferric ions initiates and catalyses the decomposition reaction of the hydrogen peroxide molecules, resulting in fast hydroxyl radical generation (Equation 4.14), known as the Fenton reaction. The efficiency of Fenton techniques and the degradation of pollutants depend entirely on several parameters, with temperature, pH, ratio [H2O2]/[Fe2+] and incidence of UV radiation being the most relevant. It should be noted that most of the tests carried out for the oily effluents treatment by Fenton technique take place at ambient temperature, without the need for reaction environment heating or cooling, since at 20°C–40°C, the process is very efficient and temperatures of approximately 50°C accelerate the hydrogen peroxide decomposition into water and oxygen, disfavouring the hydroxyl radical generation process (Babuponnusami and Muthukumar 2014).
Nanotechnological Interventions for Neurodegenerative Disorders Using Phytoactives
Published in Bhupinder Singh, Om Prakash Katare, Eliana B. Souto, NanoAgroceuticals & NanoPhytoChemicals, 2018
Sumant Saini, Charan Singh, Shikha Lohan, Atul Jain, Eliana B. Souto, Bhupinder Singh
Oxidative phosphorylation is a vital phenomenon occurring in biological systems. It is necessary for the bioenergetics of the cell. However, in the course of electron flow, leakage of a small fraction of electrons may occur from the electron transport chain (ETC) cascade; these electrons can enter the cytosol and initiate the free-radical chain-reaction mechanisms of ROS. The electrons react with molecular oxygen, leading to the synthesis of free radicals. Free radicals damage cells by oxidizing various biomolecules. Superoxides give rise to hydroxyl-free radicals that can hamper the normal neuron physiology. The hydroxyl radicals are produced via Fenton reaction by catalytic conversion from the ferrous to ferric iron radical (Korshunov et al., 1997).
Sustainable Production of Biofuels—A Green Spark: Technology, Economics, and Environmental Issues
Published in V. Sivasubramanian, Bioprocess Engineering for a Green Environment, 2018
Rajarathinam Ravikumar, Muthuvelu Kirupa Sankar, Manickam Nareshkumar, Moorthy Ranjithkumar
Lignin polymers were depolymerized by the action of hydroxyl radicals on aromatic compounds (Narayanaswamy et al., 2011). The Fenton reaction is an oxidation process in which iron donates an electron to hydrogen peroxide, and this leads to the formation of hydroxyl radical and the concomitant decomposition of H2O2 (Michalska et al., 2012). For enhanced sugar recovery, solution-phase Fenton chemistry can break down the lignin layer present in the biomass. Process conditions of this technology vary according to the range of biomass used (Zheng et al., 1995). For an efficient delignification process, it is very important to optimize the concentration of hydrogen peroxide and iron for each biomass feedstock.
Aqueous sulfide oxidation catalyzed by hydrocarbon solution of 3,3′,5,5′-tetra-tert-butyl-stilbenequinone: a kinetics and mechanistic approach
Published in Journal of Sulfur Chemistry, 2021
H. Y. Hoang, R. M. Akhmadullin, E. A. Karalin, A. G. Akhmadullina, F. Ui. Akhmadullina, R. K. Zakirov, T. L. Ton, M. U. Dao
The Fenton reaction discovered by Henry John Horstman Fenton over 130 years ago is still widely applied for wastewater treatment in the present time [15]. In which, oxidative degradation of pollutants in aqueous solution by a catalytic system of Fe (II) and hydrogen peroxide occurs. The reaction involves in situ formation of the most strongly oxidizing agents – hydroxyl radicals (OH*) which are able to react unselectively and instantaneously with the surrounding chemicals, including all types of aqueous pollutants and inhibitors [16]. The general chemical equation of the Fenton reaction (Fe/H2O2) is [17]: When excess amount of H2O2 is added, iron (III) ion further reacts with hydrogen peroxide to regenerate the catalyst.
Catalytic oxidation of aqueous sulfide in the presence of 3,3′,5,5′-tetra-tert-butyl-4,4′-stilbenequinone
Published in Chemical Engineering Communications, 2019
H. Y. Hoang, R. M. Akhmadullin, F. Yu. Akhmadullina, R. K. Zakirov, A. G. Akhmadullina, M. U. Dao
In the last few decades, advanced oxidation process based on Fenton reaction chemistry (H2O2/Fe) has been extensively implemented in removing hazardous compounds in wastewater remediation (Shih-Hsiung and Hung-Shan, 2001; Bautista et al., 2008; Brillas et al., 2009; Pliego et al., 2015). Fenton reaction was discovered in 1894 and has been applied in industrial wastewater treatment. Fenton reaction describes the activation of H2O2 by iron ion Fe2+ in forming strong oxidizing radical species (primarily HO•) via a complex reaction sequence (Fenton, 1894; Walling and Goosen, 1973; Walling, 1975):
Gaseous and liquid effluents treatment in bubble column reactors by advanced oxidation processes: A review
Published in Critical Reviews in Environmental Science and Technology, 2018
Vanessa N. Lima, Carmen S. D. Rodrigues, Ricardo A. C. Borges, Luis M. Madeira
The pH effect was also assessed for treating two distinct liquid effluents (containing p-nitrophenol (Rodrigues et al., 2018) and hydroquinone (Lima et al., 2017)) and the better mineralization of both compounds was always obtained for an initial pH of 3 (∼49 and ∼39% for p-nitrophenol and hydroquinone effluents, respectively), which decreases along the oxidation process. Rodrigues et al. (2018), after optimizing the experimental conditions, propose a strategy to improve the mineralization, which consisted of readjusting the pH to the optimum value (pH = 3) during the reaction, achieving an increase in the mineralization efficiency of ∼49% to ∼63%, thus showing the importance of this parameter in the Fenton reaction.