In this study, new composite adsorbent with enhanced thermal conductivity and adsorption capacity was synthesized and analyzed comprehensively for the development of compact CO 2 based adsorption cooling system. The consolidated composite was prepared employing activated carbon, graphene nanoplatelets and hydroxyl cellulose as a parent adsorbent, thermal conductivity enhancer, and binder, respectively. The surface area and pore volume of the composite were found to be 1778 ± 13 m 2 g −1 and 1.014 cm 3 g −1 , respectively. In addition, the composite showed 233% higher thermal conductivity compared to the parent activated carbon. Adsorption characteristics of CO 2 were measured at temperature ranging from 20 to 70 °C and pressures up to 5 MPa. Absolute uptake was evaluated from excess adsorption based on the following two methods: (i) the adsorbed phase volume is equal to the pore volume of the adsorbent; and (ii) the adsorbed phase volume is almost zero under low pressure and/or high temperature conditions. Furthermore, the averaging of above two methods was also taken for avoiding these two extreme assumptions. Obtained absolute adsorption uptake data were fitted with modified Dubinin-Astakhov and Tóth models. Results indicated good approximation between data points and models. The average isosteric heats of adsorption estimated using modified D-A and Tóth model were found to be 19.742 kJ mol −1 and 19.023 kJ mol −1 , respectively. The obtained characteristics of composite adsorbent are prerequisites for designing compact CO 2 based adsorption cooling systems.
|Translated title of the contribution||A comprehensive study to evaluate absolute uptake of carbon dioxide adsorption onto composite adsorbent|
|Number of pages||10|
|Journal||International Journal of Refrigeration|
|Publication status||Published - Apr 2019|
All Science Journal Classification (ASJC) codes
- Building and Construction
- Mechanical Engineering