efect of potassium hydroxide concentration and activation time on rice husk-activated carbon for water vapor adsorption

Rice husk carbon by-product from the industrial combustion is a promising source to produce a vast amount of activated carbon adsorbent. this research prepared rice husk-activated carbon adsorbent by varying the concentration of potassium hydroxide solution (5, 10, 15, 20 % w/v) and activation time (2, 4, 6, 8 hours). fourier-transform infrared spectral characterization (ftir) indicated a significant effect before and after activation, especially the presence of hydroxyl groups. based on the iodine adsorption, the specific surface area of the produced-activated carbon was approximately 615 m2/g. experimental results showed that increasing potassium hydroxide concentration and activation time increases the water vapor adsorption capacity of the activated carbon. compared with the rice husk carbon, the koh-activated carbon enhanced the water vapor adsorption capacity to 931%. in the adsorption observation, changing the temperature from 15 to 27 ℃ caused a higher water vapor uptake onto the activated carbon. two adsorption kinetics (pseudo-first- and pseudo-second-order models) were used to evaluate the adsorption mechanism. this research found that rice husk-activated carbon performed a higher water vapor adsorption capacity than other adsorbents (silica gel, zeolite, and commercially activated carbon).