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Carbon dioxide airborne to the atmosphere must be prevented since it will affect the Earth and produce greenhouse effect. Sequestration technology has been mainly focused for this issue. Therefore, many scientists have been researching to capture the carbon dioxide and there were successful in capturing the carbon dioxide by Carbon Capture and Storage (CCS) technology. This technology has been considered as one of the effective methods in capturing and storage the CO2 up to 90% resulted from fossil fuels.
Preventing carbon dioxide raising towards the atmosphere is important today because the Earth’s atmosphere certainly keeps the gasses which can affect the temperature of the planet. Carbon dioxide is a gas which has properties of transparent and no odour. Surprisingly, this gas can prevent the heat energy inside the planet so it will not emit to the outside of the Earth. This gas is produced daily from our electricity equipment, the combustion process from vehicles and even from the metabolism of our body. Although it is dangerous for the planet, carbon dioxide is the main fuel for plant to do photosynthesis process and producing the oxygen as the waste product.
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Based on Yang H, Xu Z, Fan M et al., which is written in journal of A.L. Yaumi, M.Z. Abu Bakar, B.H. Hameed of the University Sains Malaysia, stated the predictions of the carbon dioxide will be increasing up to 570 ppm so that it can contribute to the inclining of temperature for 1.9 centigrade in the next century. Subsequently, the global warming issue will become the major environmental problem in the future. Therefore, there must be a proper prevention for decreasing this concentration as a starting point to commence the sequestration technology.
Meanwhile, pre- and post-utilization of fossil fuels becomes dilemma. Today, many of the countries particularly for developing nations utilized the fossil fuels as the main sources of energy. For example, in Indonesia itself, fossil fuels are mainly used for the raw materials in producing electricity in every power plant. Instead of using another renewable and sustainable resources, the government of Indonesia still depends on this resources.
Therefore, preventive action has been conducted in reducing this greenhouse gas. A.L. Yaumi, M.Z. Abu Bakar, B.H. Hameed of the University Sains Malaysia, wrote research article about the methods in reducing the CO2 from airborne. They proposed seven solid materials for capturing and processing the carbon dioxide and its sequestration. They are carbon based sorbents, zeolites, metal organic framework, alkali metal carbonate based solid materials, amine based solid sorbents, unmodified composite materials and functionalized composite materials.
In general, this study reviewed these functionalized materials are used because of their adsorption characteristics and the low-cost fabrication. For instance, the carbon based sorbents which can capture the carbon dioxide because of their structure. Activated carbon, carbon nanotubes and graphene are materials which has unique system. Graphene’s structure is hexagonally multilayer so it can filter the carbon dioxide and it has high availability so it is easy to obtain.
Zeolites are one of the best materials in capturing the CO2. However, the possibility of adsorption mainly depends on the metal framework inside their structure. Subsequently, we need more efficient materials and move towards to metal organic framework materials. These materials are based on the metal structural properties which have effectively increased the level of adsorption. According to the mentioned paper, many research reported the efficient adsorption since their selectivity and capacity are higher than any suggested materials. However, the problem is due to their endurance feature in term of increasing of heat during the adsorption process even though they are easy to be modified.
In answering the previous disadvantage from each material which is mentioned above respectively, the scientists had obtained new methods and it is the materials based on alkali metal carbonate. It does not cost high expenses and high level of endurance in term of increasing temperature. With the capability in carbonation reaction, the alkali metal materials are able to react and regenerate in higher temperature particularly at 100 to 200 centigrade. The reactions are carbonation and decarbonation reactions. The utilization of alkali metal in this composite produce high temperatures materials so it can be functionalized to capture the carbon dioxide in high heat approximately up to 600 centigrade.
As far as it concerned, the alkali metals carbonate materials are the best solution in sequestration technology. However, as Ida et al., reported there was significance decreasing of performance of the materials in adsorption after attaining the equilibrium point which is also written in the same paper. Consequently, the demands in fabricating well-established materials must be obtained.
One of the materials which has selective layer inside their structure is amine. This category of materials has big porous and density, and they are fabricated through silane chemical reaction, coupling and polymerization which lead them to have better characteristics including hydrothermal stability and mechanical strength. Because of their large pore size, volume and high surface area, the load of storing the carbon dioxide is high.
The last materials which has been researching for capturing the carbon dioxide is the composite materials.
Based on the reference we cited, there are two types of composites which can operate in capturing and storing the carbon footprint. Either unmodified and modified composite materials, for instance the composite polymer, they have sensing ability in their performance. This characteristic will employ the semiconductor principle while they were capturing the CO2 gas. But, the most common disadvantage in functionalizing composite polymer sensor is the swelling effect which will happen after sequestration process inside the structure of the materials.
In conclusion, there are several materials which have been employed in addition to prevent the greenhouse gas. The issue is simply depended on the properties and performance of each material. Furthermore, the fabrication and testing aspects have found that the performance of fabricated materials fully depends on the conditions of adsorption, such as, the temperature, level of carbon dioxide nearby. Therefore, a suitable and certain material must be positioned in certain places depending on the heat and amount of carbon dioxide.
*A.L. Yaumi, M.Z. Abu Bakar, B.H. Hameed, Recent Advances in Functionalized Composite Solid Materials for Carbon Dioxide Capture.