Chemical reduction of nitrate

Chemical reduction of nitrates has also been employed ... 

Fanning, J.C. 2000. The chemical reduction of nitrate in aqueous solution. Coord. Chem. Rev. 199 159-179. 

Young GK, Bungay HR, Brown LM, Parsons WA. Chemical reduction of nitrate in water. J Water Pollut Control Fed 1964 36 395-398. 

Buresh R. J. and Moraghan J. T. (1976) Chemical reduction of nitrate by ferrous iron. J. Environ. Qual. 5, 320-325. 

Under anaerobic reduction conditions they are biochemically reduced to nitrites, elementary nitrogen or nitrogen monoxide, and eventually even to ammonia nitrogen. The chemical reduction of nitrates is also possible, in iron waters in alkaline media. 

It was also reported (Huang et al, 1998 Su and Puls, 2004 Yang and Lee, 2005) that the system pH would greatly affect the reduction efficiency of nitrate. In general, chemical reduction of nitrate would drop when the system pH was greater... 

Yang GCC, Lee HL. (2005). Chemical reduction of nitrate by nanosized iron Kinetics and pathways. Water Research 39 884—894. 

Rahman A, Agrawal A. Reduction of nitrate and nitrite by iron metal implications for ground water remediation. 213th National Meeting, San Francisco, CA American Chemical Society 1996 37(1) 157-159. 

The reaction of Mo(H20)63+ and nitrate in aqueous solutions results in the formation of Mo2Oi(H20)62+ and nitrite. Mo(III) coordinated to oxygen and nitrogen donor atoms of EDTA also reduces nitrate in aqueous solutions. The reduction of nitrate by a Mo(III)-EDTA complex results in the formation of nitrite and a Mo(V)-EDTA complex, as determined by chemical and spectrophotometric techniques. These reactions serve as models for biological nitrate reduction. In addition, molybdate coordinates to naturally produced phenolates. The molybdenum-coordinating phenolates also coordinate tungstate and ferric iron. Two of these phenolates contain threonine, glycine, alanine, and 2,3-dihydroxybenzoic acid. 

Ottley C. J., Davison W., and Edmunds W. M. (1997) Chemical catalysis of nitrate reduction by iron(ll). Geochim. Cosmochim. Acta 61, 1819-1828. 

Anderson (11) was the first to report on the use of FIA for the analysis of seawater micronutrients. He developed a method for the simultaneous determination of nitrate and nitrite. The chemical reactions for the analysis of nitrate were based on the reduction of nitrate to nitrite by a copper-ized cadmium column placed in the flow path. The nitrite was then analyzed as an azo dye (11). This reaction sequence is conventionally used in both segmented CFA and manual analyses of nitrate and nitrite in seawater (2, 6, 7). The detection limits are 0.1 fxM for nitrate and 0.05 juM for nitrite. 

Anaerobic organisms are able to use oxidized chemical species such as nitrate (NO ) as electron acceptors in place of molecular oxygen. Consequently, microbial reduction of nitrate to N2 (a process termed denitrification ) occurs in the early stages of soil reduction, as does Mn oxide reduction to Mn. Reduced species such as nitrite (NO ) and Mn then appear in solution. As more extreme reducing conditions develop, ammonium (NH ) accumulates from nitrogen reduction reactions, and iron solubility increases in the form of Fe. The elevated iron and manganese solubility is ultimately limited by precipitation of the rather insoluble carbonates of Fe (siderite) and Mn (rhodochrosite) if the soil pH is not too low ... 

Chemical catalysis of nitrate reduction by iron(II). Geochimica Cosmochimica Acta, 61 1819-1828. 

Nitrites occur as the simple NO anion. It is formed particularly by biochemical oxidation of ammonia nitrogen or biochemical reduction of nitrates. Some industrial wastewaters are very rich in nitrites, for example those from the production of some dyestuffs or from engineering works employing cutting liquids for cooling of machine tools such liquids contain nitrites as corrosion inhibitors. Nitrites in waters occur with nitrates and ammonia nitrogen only at low concentrations since they are biochemically and chemically labile. In clean ground- and surface waters only trace... 

Phosphorous is not the only nutrient that can be retained/removed via reactions in the subterranean estuary. The microbial reduction of nitrate to inert dinitrogen gas, a process known as denitrification, is known to occur in the redox gradients associated with fresh and saline groundwater mixing. Conversely, ammonium, which is more soluble in saline environments, may be released within the subterranean estuary s mixing zone. While the overall importance of SGD on the global cycle of certain chemical species remains to be seen, there is little doubt that SGD is important at the local scale both within the United States and throughout the world. 

Chemical equations must be balanced to show the correct quantities of reactants and products. Study the following unbalanced equation for the reaction that occurs when copper metal is placed in concentrated nitric acid. This reaction is shown in Figure 19.6. The brown gas that is produced is nitrogen dioxide (NO2), from the reduction of nitrate ions (N03 ), and the blue solution is the result of the oxidation of copper (Cu) to copper(II) ions (Cu +). 

Other energy-producing reactions of organisms involve the reduction of oxygen to water, the reduction of nitrate to ammonia and nitrogen gas, the reduction of sulfate to sulfide, and the reduction of carbon dioxide to methane. All of these reactions can exert a profound effect on water quality especially when it is realized that the affected chemical species also engage in many other chemical reactions. For example, the sulfide ion forms precipitates with many heavy metals. The microbial reduction of sulfate to sulfide could be accompanied by a reduction in the dissolved heavy metal content in a natural water. 

Silver nanoparticles of 23 nm size were formed in aqueous medium by chemical reduction of silver nitrate in excess of aqueous sodium borohydride. To examine the aggregation of the produced silver nanoparticles they were coated either with polyethylene glycol or poly(diallyldimethylammonium chloride). 

Other homogeneous reactions that may occur within occluded regions include redox reactions and other chemical reactions. For example, it has been proposed [17] that nitrate acts as an inhibitor within occluded regions such as pits or crevices via the reduction of nitrate to am-... 

Daub, K., Emig, G., CholUer, M.-J., CaUant, M., Dittmeyer, R., 1999. Studies on the use of catalytic membranes for reduction of nitrate in drinking water. Chemical Engineering Science 54,1577-1582. 

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