International Journal of Technology (Dec 2018)
Sulfur Dioxide Gas Adsorption Study using Mixed Activated Carbon from Different Biomass
Abstract
Activated carbon produced from coconut shell and rubber seed pericarp has a great potential to be used as gas adsorbent. Most researchers, however, focus on producing activated carbon from one single biomass. Another option is to produce activated carbon from blending two different types of biomass with the strategy to reduce dependency on one type of biomass and sustain the production of activated carbon. Further, the adsorption capacity of the activated carbon produced from different blended biomass would be increased in comparison to single biomass. Most activated carbon is produced via physical activation using the conventional pyrolysis heating system, which is very time-consuming. In this study, activated carbon from biomass, namely coconut shell (CS-AC), rubber seed pericarp (RSP-AC), and their blends (CSRSP-AC) were successfully produced by using ZnCl2 as the chemical activating agent. The activation process was performed in a modified commercial microwave oven at the irradiation power of 600 W for 20 min. The single activated carbon and its blend were tested for their adsorption capacity for sulfur dioxide gas (SO2) using evolved gas analyzer (EGA). The single RSP-AC and CS-AC samples produced breakthrough time for SO2 adsorption at 23 min and 14 min, respectively. The longest SO2 breakthrough time for the blended activated carbon (CSRSP-AC) was achieved at 15 min with a ratio of 20:80 (CS:RSP) and was slightly longer than the individual CS-AC. The high amount of microporous RSP in the blend increases SO2 adsorption capacity. The presence of fly ash/Ca(OH)2 catalyst in the blended CSRSP-AC (20:80) further improves SO2 adsorption capacity with the breakthrough time achieving at 36 min at the adsorption temperature of 35oC. The SEM micrograph of blended CSRSP-AC with the addition of fly ash/Ca(OH)2 catalyst after SO2 adsorption showed that the pores were clogged with some of the samples agglomerated and clustered, indicating that both activated carbon and fly ash/Ca(OH)2 catalyst had interacted thoroughly with SO2 after the adsorption process.
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