NH₃ Adsorption Performance of Silicon-Supported Metal Chlorides

Abstract

Alkaline earth metal chlorides (AEMH) are considered to be the key to effectively solving the problem of NH 3 storage due to their ability to react with NH 3 to form stable ammonia complexes. This study attempted to investigate the NH 3 adsorption performance of four metal chlorides (CuCl 2 , MnCl 2 , MgCl 2 , and CaCl 2 ) and silicon-supported composite adsorbents with a fixed bed. The adsorbents were characterized by X-ray diffraction, Brunauer−Emmett−Teller, and scanning electron microscopy to analyze the NH 3 adsorption behavior. The experiment found that the NH 3 adsorption capacity of four metal chlorides is in order: CuCl 2 > MnCl 2 > MgCl 2 > CaCl 2 , and the adsorption capacity of metal chlorides decreased with the increase in temperature. In addition, the composite adsorbents of silicon-supported metal chlorides were synthesized by the wet impregnation method. Ammonia adsorption experiments showed that silicon can significantly improve the NH 3 adsorption capacity of metal chlorides, and the NH 3 adsorption capacity of MnCl 2 /silicon was 127.5% higher than that of MnCl 2 . Silicon played the role of the skeleton support in the metal chloride particles, hindering the agglomeration between particles and increasing the number of pores on the surface of the particles, which was conducive to the diffusion of NH 3 through the pores into the particles for adsorption.

Large-Scale and Highly Efficient Production of Ultrafine PVA Fibers by Electro-Centrifugal Spinning for NH3 Adsorption

“…Various adsorbents have been investigated for the removal of NH 3 leakage. In addition, as a sustainable fuel, NH 3 has become more promising in the fuel cell industry, thereby stimulating the material researches for NH 3 storage [ 49 , 50 ]. Due to the multiple hydroxyl groups of PVA molecules which can interact with NH 3 molecules, PVA ultrafine fibers would be a good candidate as the NH 3 adsorbent [ 49 ].…”

“…NH 3 molecules can be adsorbed via constructing hydrogen bonds with hydroxyl groups of PVA molecules on the surface of fibers, which make a contribution to inducing the gate opening at relatively low pressures [ 49 ]. Although the obtained PVA fibers present lower adsorption capability than MOF (Metal-organic framework) materials for NH 3 adsorption [ 50 ], the much lower price of PVA products is still very competitive. In addition, the NH 3 adsorption performance of PVA fibers can be further improved by the introduction of hierarchically porous structures [ 11 , 51 ].…”

XCl2/MWCNTs─Composites Based on Multi-Walled Carbon Nanotubes and Metal Chlorides for NH3 Capture and Separation

“…Composite sorbents of MWCNTs and metal chlorides were prepared by the wet impregnation method. This method has also been used in our previous study . MWCNTs were immersed in an aqueous chloride solution and evenly dispersed with a constant temperature magnetic stirrer at 2000 r/min.…”

NaBr-Impregnated Graphene Aerogel for Ammonia-Based Adsorption Heat Pump Application

“…Adsorption heat pumps (AHPs) that can be powered by this low-grade thermal energy and employ environmentally friendly refrigerants are a potential solution for two of the most pressing issues of the current time: increasing energy demand and pollution . Ammonia is a high-efficiency refrigerant that can be used in ammonia-based adsorption heat pumps (AAHPs) for greener energy transportation. − However, toxicity and the high storage pressure of ammonia are a bottleneck for its use in stable and efficient refrigerant systems and are a global concern. − The efficient functioning of AAHPs relies on certain essential properties of adsorption materials such as high adsorption capacity, adsorption rate, desorption rate, and cyclic stability; and surface area, porosity, and affinity to ammonia are critical factors in determining their adsorption properties. Ammonia can primarily adsorb onto an adsorbent surface through physical or chemical adsorption mechanisms.…”

“…To address this challenge, extensive research has been conducted to prepare composite materials of metal halides and physical adsorbents such as activated carbon (AC), expanded natural graphite (ENG), carbon nanotubes (CNT), MOFs, etc. ,− These studies demonstrate the potential of composite adsorbents to enhance the performance of NH 3 adsorption systems. For example, the addition of MWCNTs into the CaCl 2 showed an adsorption capacity as high as 0.9 g/g and was found to avoid agglomeration and prevent adsorption performance attenuation .…”