커피폐기물을 이용한 고기능성 다공성 발포체 개발 및 그 응용

Abstract

Ceramic foams exhibit various micro-structures and mechanical properties with different functions, including separation, storage and heat shielding, which depends upon the composition and manufacturing process. Also, ceramic foams are lightweight structural material due to low density, high specific surface area and high specific strength. Therefore, the ceramic foams are one of the validating materials that increase their application range in various fields such as catalyst bed, filter, electrode material for fuel cell, insulation material, sensor and so on. Currently, the cost of recycling waste coffee powder is increasing as the domestic coffee market grows. Therefore, a most efficient way needed to recycle waste coffee powder. In this context, our studies focused on production of ceramic foams using waste coffee. In order to produce the ceramic foam using waste coffee, initially, the carbonization process condition of has been done. The waste coffee was carbonized on a hot plate at 400 oC. The cellulose particles of waste coffee are maintained for 3 hours for the carbonization, and the ratio of C is highest as a result of carbonization for 3 hours. The ceramic foam has many pores and advantageous to thermal transfer by structural features. By utilizing the advantage of thermal transfer, a heat sink was developed using the synthesized ceramic foam from waste coffee. A universal testing machine was used to measure the compressive strength. The compressive strength of ceramic foam using waste coffee was about 3.384 MPa. The temperature of LED(light emitting diodes) PCB(printed circuit board) after protecting with the synthesized ceramic foam was about 53.6 °C, and the performance of the aluminum heat sink was confirmed to be 99.8%. In addition, it was confirmed that the hybrid type manufactured by adding ceramic foam as the heat sink has better performance than the conventional heat sink. The approach for developing the heat sink is very simple and cost-effective. The synthesized ceramic foam facilitates the manufacturing process with higher durability of LED PCB, which results in the cost-effective material. Therefore, waste coffee based ceramic foams are readily available to replace the existing aluminum heatsink. We synthesized a waste coffee based ceramic foam for its utilization in constructing materials. The compression strength of ceramic foam block was about 2.31 MPa, and the far-infrared emissivity and emission power of foaming ceramics for construction materials were confirmed 0.917 and 369.610 W/(m2·μm), respectively. The deodorization rate of NH3 and H2S of the ceramic foam for construction materials were 83.7% and 99.8%, respectively. The foaming ceramic for construction materials was satisfied the standard of the emission of environmentally hazardous substances when compared with standard values. We applied the developed ceramic foam for the water filter. After using ceramic foam as a filter for water purification, it was confirmed that no substances other than lead and arsenic were detected. All of the values are below the reference value, and it can be confirmed that the harmful component does not dissolve in the foam ceramic. After a long period of time, the pH was measured higher on the water-quality test, but it seems to be possible to apply as a water filter for purification of water quality. In conclusion, we confirmed that the ceramic foams using waste coffee powder have various functionalities and it could be applied in various fields.