Preparation of Activated Carbon by Reduction of SO2 Adsorbed on Palm Oil with Microwave Energy

Abstract

The preparation of activated carbon from palm oil shell by activation with microwave energy was divided into three steps: carbonization, sulfur dioxide adsorption, and microwave activation. The first step - carbonization - was carried out at 400oC for 60 min. The characteristics of char were: yield 31.72%, volatile matter 18.87+0.06%, fixed carbon 69.41+ 0.09%, and BET surface area 152+4 m2 g -1 .

Sulfur dioxide, 2,000 ppm, was adsorbed for 420 min by the prepared char until reaching the equilibrium at room temperature in the reactor, diameter of 5 cm, and height of 30 cm.

The activation with microwave energy was carried out in Pyrex tube (U-shaped) reactor, diameter of 28 mm, length of 150 mm, and height of 100 mm. The reactor was set up in a microwave oven. The variables studied were: activation time (range of 30- 180 min), activation energy (range of 225-500 watt), and number of cycles of adsorption and activation from 1 to 4 times. The optimum conditions from experimental results were: activation time of 90 min, activation energy of 450 watt, and second cycle of adsorption and activation. The characteristics of activated carbon produced at the optimum condition were: iodine adsorption number 1385+ mg g-1 , methylene blue adsorption number 235+6 mg g-1, bulk density 0.659 g cm-3, pH 8.11, surface area 1172+49 m2 g-1 .