Possibilities of Using Zeolites Synthesized from Fly Ash in Adsorption Chillers

Abstract

Adsorption chillers produce cold energy, using heat instead of electricity, thus reducing electrical energy consumption. A major industrial waste, fly ash, can be converted to zeolite and used in adsorption chillers as an adsorbent. In this research, three different types of zeolites were synthesised from fly ash via a hydrothermal reaction in an alkaline solution (NaOH). The obtained samples (Na-A zeolites) were modified with K2CO3 to increase the water adsorption capacity of these samples. Phase and morphology analyses shows that desired zeolites formed properly but other crystalline phases also exist along with nonporous amorphous phases. The determined specific surface areas for Na-A zeolite (12 h) and Na-A zeolite (24 h) are 45 m2/g and 185 m2/g respectively, while the specific surface area for synthesized 13X zeolite is almost negligible. Water-isotherm for each of these samples was measured. Considering the application of adsorption chillers, average adsorption capacity was very low, 1.73% and 1.27%, respectively, for the two most probable operating conditions for synthesized 13X zeolite, whereas no water was available for the evaporation from Na-A zeolite (12 h) and Na-A zeolite (24 h). This analysis implies that among the synthesized materials only 13X zeolite has a potential as an adsorber in sorption chillers.

Zeolite‐based polymer composite films for vegetables and fruits packaging: A review

“…91 Many investigations measured sample weight loss by weighing the samples before and after storage days, with measurements carried out in three replications. 73 In Hanula et al 9 work on the effect of different percentages of Zeolite and açai extract on the shelf life of button mushrooms, weight loss increased linearly with each day of storage (7,14,21,28). The weight loss varied between 0.15% (PVC, day 7) and 0.85% (PVC, day 28), and it also varied between (Control, day 28).…”

“…The most commonly used Zeolites in industry are of type A, X, and Y. 14 Synthetic Zeolites are more expensive than natural Zeolites because of the cost of raw materials and the energy required for the synthesis reaction. However, synthetic Zeolites have more uniform pore sizes and shapes, making them more suitable for certain applications such as catalysis and separation processes.…”

“…13 Also, natural Zeolites have poor and moderate sorption capabilities due to their extremely low specific surface area. 14 In line with circular economy principles, these zeolitic materials can be recovered after use, washed, and reused until their structures remain undamaged. Residual Zeolites obtained from hydrothermal processes can also be reintroduced to create new Zeolites.…”

“…The most commonly used Zeolites in industry are of type A, X, and Y 14 . Synthetic Zeolites are more expensive than natural Zeolites because of the cost of raw materials and the energy required for the synthesis reaction.…”

“…On the other hand, natural Zeolites are cheaper and more abundant than synthetic Zeolites 13 . Also, natural Zeolites have poor and moderate sorption capabilities due to their extremely low specific surface area 14 . In line with circular economy principles, these zeolitic materials can be recovered after use, washed, and reused until their structures remain undamaged.…”