Papers by Keyword: Ammonium Chloride

Abstract: Pyrolytic technology was developed to grow Zn-based nano- and microstructures. It was based on the application of a mixture of ammonium chloride, Zn and ZnO powders as source materials. Two temperature profiles were used for the synthesis. In the first and second growth processes, the maximum substrate temperatures of 250 and 410°C were reached, respectively. The granular layer of micrometer range ZnO crystals was produced in the first process. By depleting the source with NH₄Cl, the Zn polyhedra, and layered spheres were produced within 50–65 min in the second process. By increasing the NH₄Cl content in the source to 0.9 g, the Zn/ZnO core–shell spheres were synthesized. The further increase of process duration led to the out-diffusion of Zn from the core, its oxidation, and the formation of a thick, dense ZnO spherical shell. Even further annealing in residual gases caused the increase of the Zn vapor pressure inside the shell. As a result, at a certain Zn vapor pressure, the shell bursts, causing the formation of a hollow ZnO microsphere.

Abstract: In order to protect the oil&gas reservoirs, a surfactant vinyl cationic clay (Na-MMT) anti-swelling agent diethyl dodecyl allyl ammonium chloride (DDAAC) was prepared from diethylamine, chlorododecane and allyl chloride as raw materials. The single-factor orthogonal test was used to determine the optimal synthesis scheme for DDAAC: reaction temperature 40 °C; reaction time 4 h; pH= 9; n (diethylamine): n(chlorododecane): n(allyl chloride) = 1.1:1.0:1.8. The experimental results showed that the anti-expansion rate of 0.5wt% DDAAC can reach to 78.31%. FT-IR were utilized to study its anti-expansion mechanism, and FT-IR showed that physicochemical adsorption between DDAAC and Na-MMT occurs.

Abstract: Methylammonium lead trihalide perovskites have emerged as attractive materials for solar cell applications. The major eminence of this materials can be crystallized via various solution methods to produce the solid state of thin films. However, the crystallinity of perovskite depends on the composition of perovskites. Here, we study NH₄Cl and NH₄Br as precursor additives for improving crystallinity of perovskites. Perovskite was synthesized by mixing precursor solutions of CH₃NH₃I and Pb(Ac)₂with or without additives NH₄Cl and NH₄Br using the one-step spin-coating method. By characterizing the thin films using XRD, SEM and UV-Vis spectrophotometer, we found anion Cl and Br performed an important role toward crystallinity, morphology, and optical absorption of perovskites, respectively. Meanwhile, ammonium has assisted to facile remove the residual DMSO solvent confirmed by FTIR. These results shed light on using ammonium halides as potentially dual side additives in the synthesis of perovskites.

Abstract: Titanium oxycarbonitride (TiO_xC_yN_z) produced from Malaysian ilmenite consists of impurities such as iron that adversely affect the efficiency of chlorination process. In this paper, the dissolution of iron present in TiO_xC_yN_z was performed using ammonium chloride (NH₄Cl) solution at 70 °C from 4-6 hrs. Effects of acid concentration, catalyst amount and leaching time on the rate of iron dissolution were also investigated. Microstructural and/or morphological studies of the raw materials, and products were carried out by X-ray diffraction (XRD), X-ray Fluorescence (XRF), scanning electron microscopy (SEM), and Energy Dispersive X-ray analysis. The results obtained from SEM/EDX analysis for the reduced samples HR15 (15% Polystyrene (PS) + 85% coal (C)), HR25 (25% PS + 75% C) and HR35 (35% PS + 65% C) showed that most of the Titanium oxycarbonitrides were found in the circular shape with increase grain coarsening. Iron dissolution was accelerated with acid concentrations and it increased with increasing leaching time from 4 to 6 hrs. The results also showed that the percentage of Fe removed from titanium oxycarbonitride was ~ 76.85% at 70 °C for 6 hrs with the PS/C ratio of 0.18 and 1 wt. % of glucose as catalyst.

Abstract: The present study aims to investigate the structural and ionic conductivity of carboxymethyl cellulose - ammonium chloride as proton conducting polymer electrolytes. The complexion of polymer electrolyte films has been confirmed via FTIR studies. The conductivity enhancement with the addition of ammonium chloride concentration was proved due to the increase in amorphous nature of the films as evidenced by XRD analysis. Impedance studies indicate that the highest ionic conductivity of 1.43 x 10^-3 Scm^-1 was observed with the addition of 16 wt.% ammonium chloride in polymer electrolyte system obtained at ambient temperature.

Abstract: In this study, the leaching effect of copper oxide ore was investigated using ammonium chloride solution as leaching agent. The effects of temperature, concentration of ammonium chloride, average particle size and stirring speed on the leaching of copper oxide ore were investigated. The leaching rate increased with increasing solution temperature, concentration, and stirring speed as well as with decreasing average particle size. Ammonium chloride solution can therefore be used as an effective leaching agent for copper extraction from copper oxide ore.

Abstract: The ternary system of solid-liquid phase equilibrium relation of KCl-NH₄Cl-H₂O was studied at 80 °C. The solubility data of KCl and NH₄Cl in water were obtained by isothermal equilibrium method, and the phase diagram of the system was plotted. The result showed that this system exist six phase regions: i.e. the unsaturated solution region, pure KCl , pure NH₄Cl, the solid solution base of KCl, the solid solution base of NH₄Cl and their common crystallization region with the solid solution base of KCl and the solid solution base of NH₄Cl crystallization regions. Some crystallization area will be changed with the various temperature, According to the phase diagram, it can be calculated the quantity of evaporated water in the crystallization process of KCl-NH₄Cl-H₂O and controlled the change of concentration in the evaporation process preferably.

Abstract: The use of coal fly ash for CO₂ sequestration has been proposed as a promising option for its utilization. However, research is quite necessary for advancing this technology. Indirect carbonation of high-calcium coal fly ash for CO₂ sequestration was investigated in this study. In these processes, calcium was first extracted from a high-calcium coal fly ash sample with NH₄Cl solution. The obtained leachate was subsequently carbonated by bubbling CO₂. It was shown that NH₄Cl could extract about 35% of the total calcium into the solution under the conditions investigated. The dissolution of calcium is nearly accomplished in half an hour. Further increasing the extraction solution temperature (10-90°C) and the concentration of NH₄Cl (0.5-3mol/L) only has subtle positive effects on the calcium extraction efficiency. The carbonation efficiency of the extraction leachate, namely the percentage of the calcium in the solution transformed into calcium carbonates is about 47%. The sharp drop in pH after bubbling CO₂ due to weak acid buffering capacity of the solution hinders the further precipitation of Ca²⁺. Calcium carbonate samples with a purity of up to 97% are obtained, meeting the purity requirements for industrial use.

Abstract: The influence of equiaxed crystal movements in a superheated environment on the melt kinetics of the equiaxed crystals was experimentally investigated by observation of the settling and melting behaviors of NH4Cl equiaxed crystals in its aqueous solution. The experimental set-up composed of the settling tubes, water bath and video capture device, where NH4Cl equiaxed crystals were acquired in a cooling zone and then introduced into the superheated settling tubes filling with NH4Cl-H2O model alloy, and the morphologies of the equiaxed crystals were video captured for further analysis. Two kinds of morphology evolution have been observed, and the difference was related with typical spinning movements of the equiaxed crystals during their sedimentation. Changes of the length of six primary dendrite arms have been measured; the results were compared with the calculated melting rate for equiaxed crystals without any convection. It has been shown that the convection induced by the sedimentation imposes a strong influence on the melting kinetics of the equiaxed crystals.

Abstract: 3-Methylthiopropionaldehyde diethyl acetal was synthesized from the reaction of 3-methylthiopropional with ethanol and triethyl orthoformate. The effecting factors including the kinds of catalyst, the mole ratio of raw materials, the amount of catalyst and the reaction time were optimized. The structure of product was characterized by gas chromatography, infrared spectroscopy, mass spectrometry, and nuclear magnetic resonance. Additionally, the mechanism of the reaction was speculated; the odor characteristics were evaluated.