جستجوی مقالات مرتبط با کلیدواژه « ammonia » در نشریات گروه « شیمی »

A plant was developed that uses a sulfur-ammonia thermochemical water-splitting process for H2 production. Hydrogen is beneficial as a fuel in different industries and automobiles. Aspen Plus was used for the simulation of hydrogen plant modeling. This process consists of electrolytic oxidation of ammonium sulfite and the thermal breakdown of potassium pyro sulfate and SO3 in the oxygen production half cycle. The reactions are carried out by solar thermal energy. The inlet stream is water, and the product streams are H2 and O2 gas. This research focuses on scrutinizing the economic strength of hydrogen production by electrolysis. During the research, it is clear that this type of study has great potential to reduce carbon emissions. That there is concluded economic potential for the electrolytic system. The model is for the full-scale operation that will produce approximately 1.3 lac kg H2 / day. It is equal to 370MW. Design specifications were placed in strategic areas of this model to aid in its conversions. Model convergence is complex because of various material and energy recycle loops within the plant. The overall electricity needed to start the process is intramural from squandering heat. The thermal energy storage system will operate continuously without any shutdown. Three substitutes for hydrogen production from solar thermal energy have been inspected from both an efficiency and economic point of view. This observation shows that the possible alternative using solar energy with the help of thermochemical water splitting to manufacture H2 is the best one. The other methods consider the direct conversion of solar energy into electrical energy by Si cells and H2O analysis. The usage of solar energy to power a vapor cycle leads to the production of electrical energy.

Extraction of ammonia compounds from food samples is a challenging topic due to the hydrophilic property of ammonia. A simple and rapid extraction method was developed for the determination of ammonia in a type of local bread (Ahari bread) and milk samples using a salting-out assisted liquid-liquid extraction and spectrophotometry. Acetonitrile was used to clean up, and potassium chloride salt solution was added to separate the acetonitrile and aqueous phase by creating two phases. The ammonia concentration in the aqueous phase was determined based on a colorimetric method. Various parameters affecting absorption intensity were optimized using the response surface methodology. Then, the optimized parameters were applied to establish a valid analytical method. The developed method was used to quantify ammonia compounds in food samples, i.e. Ahari bread and milk, by the standard addition method. The linearity of the method was from 2.5 to 40 μg/mL with a coefficient of determination (R2) of 0.994, and numerical values of a limit of detection (LOD), and limit of quantification (LOQ) was found to be 0.038 and 1.29 μg/mL, respectively. The accuracy (%error) and precision (%relative standard deviation) were in the acceptable range. The established extraction technique and standard addition method could detect ammonia in real food samples. These data showed that the established analysis approach is a simple and sensitive technique for extraction and determination of ammonia concentration in foodstuff.

In this study, the various properties including the stability energies, structural and electronic aspects of the hydrazine (N2H4), carbon monoxide (CO) water (H2O) and ammonia (NH3) molecules adsorptions on the top of the boron nitride nanoparticles (BNn) were studied through the Minnesota Functionals computations, DFT/M06-2X. The calculations clarifies that the most stable adsorption configurations are those in which the oxygen, carbon, oxygen and nitrogen atoms of CO2, CO, H2O and NH3 are closed to the boron atom of the nanoparticle, respectively. The absorption energies were obtained about -0.14, -0.15, -0.87 and -1.54 eV for abosorption of CO2, CO, H2O and NH3 gasses. The geometry optimizations, energy calculations and NBO charge transfer were used to evaluate the sensing ability of BNn for different analytes. The computed density of states (DOS) clarifies that a strong orbital hybridization take place between CO2, CO, H2O and NH3 and BNn in adsorption process. Finally, it is concluded that the BNn nanoparticle has greater response selectivity toward NH3 compared to CO, CO2 and H2O