In the world, 8.127.900 tons of eggshells are produced annually as waste. Turkey's annual consists of 123 420 tons of egg shell. As a result of the researches, it is understood that the storage of these waste eggshells is a costly process and also causes various problems such as odor problem, fly problem and spoilage. Various thermochemical (gasification, pyrolysis) methods can be used in order not to waste the calorific value of the egg shell and to be disposed of without harming the environment. The calorific values ??of local lignites in our country are low, whereas their sulfur content is high. Therefore, its use outside thermal power plants is prohibited under normal conditions due to its efficiency-emission ratio. In this study, emission measurements were made in the flue gas obtained by mixing and burning domestic Kale lignite with egg shell in different proportions in a bubbling fluidized bed. In this way, both the calorific value of the eggshell was used and the sulfur value of Kale lignite was reduced. The main purpose of this study is to reduce the CO2 emissions of egg waste generated during the use of domestic Kale lignite and to prevent environmental damage and cost loss during storage of egg shell waste.
LITERATURE STUDIES FOR THE ADSORPTION OF CO2 EMISSIONS WITH THE USE OF EGG SHELL
1. Brief Summaries of CaO Nanoparticle Synthesis Methods
Different methods are used in the literature to increase the CaO amount in eggshell.
1.1. Superficial Calcination
A total of 50 nm calcium oxide nanoparticles were obtained by heat treatment of calcite at 900 ° C for 5 hours followed by lime hydrolysis [1].
1.2. Microwave Radiation Emission
By microwave process, calcium oxide nanoparticles are produced within 5 minutes at 160 ° C with an average particle size of 14 ~ 24 nm [1].
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2.5.1.3. Co-precipitation
CaO nanoparticles are synthesized by co-precipitation in the presence of polyvinylpyrrolidone (PVP) reagent to control coagulation. The average time for this synthesis at 40 ° C is 12 hours.
The average size of nanoparticles is 100 nm [1].
1.4. Decomposition by Direct Heat
Calcium oxide nanoparticles were synthesized by direct thermal decomposition method at 80 ° C by blowing inert argon gas with an average particle size of 91 nm to 94 nm.
Chemical co-precipitation was applied for the synthesis of calcium oxide nanoparticles in the presence of polyvinyl alcohol. The treatment was carried out at 80 ° C for 60 minutes. The average particle size formed is 11 nm [1].
CaO nanoparticles were synthesized from shrimp cells in a two-step process with a mean particle size of 40 to 130 nm [1].
Crystallite sized calcium oxide nanoparticles were obtained by the 2-stage thermal decomposition method [1].
A total of 50-198 nm calcium oxide nanoparticles were obtained at ambient temperature, with less cost, additive, shorter time and a calcination temperature of 900 ° C for only 1 hour [1].
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Left gel technique is a simple, inexpensive process that requires low temperature and pressure. It is a process that can use waste materials. Calcium oxide nanoparticles are synthesized from eggshell [1]. It is obtained in 4 successive stages: 1. Waste egg shells are washed first with warm water and then with deionized water. It is dried for 2 hours at 120 degrees. It is powdered. It is sieved on a 10 micron sieve.
2. Add 250 mL of 1Molar HCl to 12.5 g of powdered raw egg shell. In this way Sol is obtained.
CaCO3 + 2HCl > (CaCl2 + H2O + CO2) > SOL
3. 250 ML of 1M NaOH solution is added dropwise to the sol and mixed to obtain gel.
CaCl2 + 2NaOH > (CaOH2 + 2NaCl) > GEL
4. Let the GEL stand overnight, filter it, wash the contaminants on the surface with distilled water, then dry. Dust is formed. The resulting powder is dried in an oven at 60 degrees for 24 hours, calcined at 900 degrees for 1 hour.
Thus, CaO is obtained.
CaOH2 (s) + ISI > CaO (s) + H2O
In this study, synthesis of calcium oxide nanoparticles from waste eggshells by sol-gel method is described. Sol-gel technique is simple, economical, does not require expensive equipment, does not require ambient temperature and pressure, and other applications for synthesizing metal oxide nanoparticles.
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It has many important advantages over the methods. FE-SEM images of Calcium Oxide nanoparticles showed that the particles are nearly spherical in morphology. The average particle size of the nanoparticles was found to be 198 nm. However, it is stated in the study that the results obtained can be improved if higher temperatures are used. It is also stated that the synthesized nanoparticles can be applied for future studies on heavy metal removal from industrial wastewater. Using waste materials as a pioneer for synthesis makes the whole process cheaper, green and sustainable
is. It is stated that the waste eggshell can also be used for the synthesis of nano calcium carbonate, which can be applied as a filling material in the automobile and paper industry in the future [1].
REFERENCES
[one]. Habte, L. (2019) Nano-Calcium Oxide Synthesis from Waste Eggshell Using Sol-Gel Method, https://www.mdpi.com/2071-1050/11/11/3196/htm, Access date: (04.05.2020 )
