How can oxidizing agent affect the wastewater treatment quality? what is best oxidizing agent?
Ferrate is a potential water treatment chemical due to its dual functions as an oxidant and a subsequent coagulant/precipitant as ferric hydroxide. Hence, an application of Fe (VI) to wastewater could achieve both oxidative elimination of various micro pollutants and reduction in the COD, BOD, Total hardness, Chloride, Fluoride can be achieved. The aim of this study was to assess the potential of Fe (VI) to oxidise selected micro pollutants and remove phosphate during enhanced treatment of municipal waste water in a single treatment step. The waste water from pond in K.R Puram, Bangalore is treated with powerful eco-friendly oxidizing agent Fe(VI){0.005mg/L}, the parameters such as, COD, BOD,TSS, Total hardness, chloride, phosphate, ammonia, cyanide etc. are measured before and after treatment. The reduction in the COD, BOD, Total hardness, Phosphate, Ammonia, Cyanides are observed.
Fe (VI) is powerful reducing agent it reduces in acids and alkalis.
4 K2FeO4 + 10 H2O → 4 Fe (OH)3 +3O2+ 8KOH
When waste water is treated with Fe (VI) concentrations higher than 5 mg/L, it eliminates the organic compounds by more than 60%. It removes phosphates [6] from 2.5 to 0.80mg when the dose of Fe (VI) is more than 7 mg/L. It oxidises H2S to thiosulphate and sulphate at pH 9-11. H2S is formed by the incomplete oxidation of organic compounds which gives bad odour to water and has toxic nature. The oxidation of organic pollutants by Fe (VI) incorporated by nature and manmade activities reduces the COD and BOD of water samples.
3 C6H5CH2OH + 2 K2FeO4 → 3C6H5CHO + Fe2O3 + 4 KOH + H2O
8 HFeO4 - + 3 H2S + 6 H2O → 8 Fe (OH)3 + 3 SO4 2- + 2 OH-
The level of BOD and COD is an important factor in evaluating the organic pollutants in waste water. The discharge of impurities generate BOD & COD level to 5000-3000 mg/L and COD level to 1000-5000mg/ L but discharge permits only 250mg/L & 500mg/L respectively.
Oxidizing and Reducing Agents
Common Oxidizing Agents and Reducing AgentsThe Relative Strengths of Oxidizing and Reducing Agents
Common Oxidizing Agents and Reducing Agents
In looking at oxidation-reduction reactions, we can focus on the role played by a particular reactant in a chemical reaction. What is the role of the permanganate ion in the following reaction, for example?
2 MnO4-(aq) + 5 H2C2O4(aq) + 6 H+(aq) 10 CO2(g) + 2 Mn2+(aq) + 8 H2O(l)
Oxalic acid is oxidized to carbon dioxide in this reaction and the permanganate ion is reduced to the Mn2+ ion.
Oxidation:H2C2O4 CO2+3+4Reduction:MnO4- Mn2++7+2
The permanganate ion removes electrons from oxalic acid molecules and thereby oxidizes the oxalic acid. Thus, the MnO4- ion acts as an oxidizing agent in this reaction. Oxalic acid, on the other hand, is a reducing agent in this reaction. By giving up electrons, it reduces the MnO4- ion to Mn2+.
Atoms, ions, and molecules that have an unusually large affinity for electrons tend to be good oxidizing agents. Elemental fluorine, for example, is the strongest common oxidizing agent. F2 is such a good oxidizing agent that metals, quartz, asbestos, and even water burst into flame in its presence. Other good oxidizing agents include O2, O3, and Cl2, which are the elemental forms of the second and third most electronegative elements, respectively.
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Thanks very much for all valuable data,
now, I want to know what is the best oxidizing agent to convert organic phosphorous into phosphate ions
regards
Sodium persulfate plus ferrous sulfate can cause Sulfate radical with great oxidation potentials
thanks,
amm. persulfate actually used in the preparing of phosphorous sample into phosphate in the standard method for water and wastewater analysis but its need digestion with H2SO4 and heat. So, Can persulfate + ferrous sulfate can do the same character but without heat for normal Wastewater samples
Regards
Standard Methods have clearly stated that persulfate oxidation using ultraviolet light for a more efficient digestion is recommended. UV light should give better results
Hi,
It is very difficult to answer to very general question. There are different types of pollutants: organic, minerals. Each has its own specificities, its method of oxidation and its analysis!
thanks Dr. Safia for adding answer
I mean organic phosphorous
Regards
Selecting a oxidizing agent depends on the wastewater you are going to treat. Considering the quality of the water that needs to be treated, it will determine the nature of reaction that will compete to each other. Also, the amount of oxidizing agent must be adjusted according to the reaction.
https://www.suezwaterhandbook.com/water-and-generalities/fundamental-physical-chemical-engineering-processes-applicable-to-water-treatment/oxidation-and-reduction/oxidizing-agent-selection-guide
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