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Ammonium nitrate is an important fertilizer with NPK rating 34-0-0 (34% nitrogen). [17] It is less concentrated than urea (46-0-0), giving ammonium nitrate a slight transportation disadvantage. Ammonium nitrate's advantage over urea is that it is more stable and does not rapidly lose nitrogen to the atmosphere.
Dissimilatory nitrate reduction to ammonium is a two step process, reducing NO 3 − to NO 2 − then NO 2 − to NH 4 +, though the reaction may begin with NO 2 − directly. [1] Each step is mediated by a different enzyme, the first step of dissimilatory nitrate reduction to ammonium is usually mediated by a periplasmic nitrate reductase.
Direct reduction from nitrate to ammonium, a process known as dissimilatory nitrate reduction to ammonium or DNRA, [6] is also possible for organisms that have the nrf-gene. [ 7 ] [ 8 ] This is less common than denitrification in most ecosystems as a means of nitrate reduction.
The conversion of ammonium to nitrate is performed primarily by soil-living bacteria and other nitrifying bacteria. In the primary stage of nitrification, the oxidation of ammonium ( NH + 4 ) is performed by bacteria such as the Nitrosomonas species, which converts ammonia to nitrites ( NO − 2 ).
Because of relatively low single pass conversion rates (typically less than 20%), a large recycle stream is required. This can lead to the accumulation of inerts in the gas. Nitrogen gas (N 2) is unreactive because the atoms are held together by triple bonds. The Haber process relies on catalysts that accelerate the scission of these bonds.
Nitrification is important in agricultural systems, where fertilizer is often applied as ammonia. Conversion of this ammonia to nitrate increases nitrogen leaching because nitrate is more water-soluble than ammonia. Nitrification also plays an important role in the removal of nitrogen from municipal wastewater.
When a solution of nitrate ions is mixed with aqueous sodium hydroxide, adding Devarda's alloy and heating the mixture gently, liberates ammonia gas. After conversion under the form of ammonia, the total nitrogen is then determined by Kjeldahl method. [7] The reduction of nitrate by the Devarda's alloy is given by the following equation: 3 NO −
Ceric ammonium nitrate (CAN) is the inorganic compound with the formula (NH 4) 2 [Ce(NO 3) 6]. This orange-red, water-soluble cerium salt is a specialised oxidizing agent in organic synthesis and a standard oxidant in quantitative analysis .