Potassium nitrate

About: Potassium nitrate is a research topic. Over the lifetime, 3537 publications have been published within this topic receiving 29450 citations. The topic is also known as: Nitric acid, potassium salt & Saltpeter.

Removal of chlorine ions from Ru/MgO catalysts for ammonia synthesis

Abstract: The effects of the removal of chlorine and the KNO3 promoter were studied on RuCl3 precursor/MgO catalysts for ammonia synthesis. Chlorine ions were decreased by increasing the temperature of reduction by hydrogen; however, chlorine still remained even after a reduction at 973 K. Both hydrogen adsorption and ammonia synthesis activity increased when increasing the reduction temperature up to 923 K which suggested that chlorine ions were removed from the ruthenium surface. Most of the chlorine ions were thought to be located on MgO (base); however, a small amount was thought to be located on the ruthenium metal surface as RuCl3 at low temperature ( <773 K ) or as MgCl2 at high-temperature reduction ( ≫ 773 K ). When the RuCl3/MgO catalyst was impregnated with the promoter ( KNO3 ) and reduced, it became effective at a K/Ru mole ratio higher than three. This suggests that potassium reacts with chlorine ions before or during hydrogen reduction, and then acts as an electron donor to the ruthenium surface. On the other hand, when the Ru/MgO catalyst is reduced with hydrogen at 773 K, then impregnated with the promoter and treated with hydrogen, KNO3 becomes effective even at a K/Ru mole ratio as low as 0.3. The potassium ions were thought to promote the ruthenium surface instead of accepting the chlorine ions in this case.

Nitrous oxide evolution rates from fertilized soil: effects of applied nitrogen

Abstract: Nitrous oxide emission from agricultural soil has been measured in two relatively long-term studies over two different soil types, Brookston clay and Fox sandy loam, located at Woodslee and Harrow Ontario, respectively. The clay plots treated with various amounts (0–366 kg N∙ha−1) of ammonium nitrate, potassium nitrate, or urea were routinely monitored for periods up to 1 yr. Extreme variability in rates within the range 109–1013 molecules∙cm−2∙s−1 was observed (1 × 109 molecules∙cm−2∙s−1 = 4.02 = 10−4 kg N∙ha−1∙day−1 = 1.68 μg N∙m−2∙h−1). Over sandy loam, rates which were lower and more uniform (108–1011 molecules∙cm−2∙s−1) showed a strong correlation with amount of NH4NO3 applied. About 0.25% of applied fertilizer was released as N2O within 80 days following treatment.