WHAT ARE CHALCOGELS?
Chalcogels are a new type of aerogel that is chalcogen-based. Aerogels are a special type of material that presents a high surface area. Chalcogels are composed of metal-chalcogen moieties that are interconnected with a linking metal ion (Riley et al.,2012). Figure 1
Physical and Chemical Properties
Chalcogels are a new family of aerogel that is not oxide-based (Katnatzidis and Bag, 2008). Zinc chalcogenide, like many other aerogels, have incredible physical properties. Chalcogels possess a very large surface area, low solid density, and a strong structure. These are highly porous semisolids made from a variety of chalcogen-based building blocks that have selective affinity for various heavy metals and gases (Bag and Kanatzidis, 2010). Zinc chalcogels are special in the way the frame is formed. Aerogel pores are filled with air instead of liquid, and this creates a highly porous solid with a massive surface area of 363520 m2/g (Oh et al.,2011). This feature makes chalcogels suitable for adsorbtion of chemicals. The zinc chalcogenide aerogels also possess high affinities toward heavy metal from the existent of sulphur and reversible absorption of strong electronaccepting molecules (Oh and Kanatzidis, 2011). These features are non-existent in other types of aerogel which do not have any chalcogens. Sulphur also brings the material semiconducting properties, and this means that it could also have application in photovoltaic solar cells and photocatalysis fields like hydrogen production (Environmental Research, 2007). Chalcogels have the ability to remove heavy metals like mercury from polluted water, separate hydrogen from other gases, and can be a very effective catalyst to remove sulphur from fossil fuel (Northwestern University, 2009).
The World’s Lightest Solid Material
Courtesy of Pacific Northwest National Laboratory
Figure 1 shows a microscopic image of zinc chalcogenide aerogel....
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