Column Performance Evaluation of Activated Carbon From Coconut Shell

Author : Hernandez, Chris de Mesa
Major Adviser : Capareda, Sergio C.
Committee Members : Abrigo Jr., Casiano S.; Movillon, Jovita L.; Acda, Reynaldo I.
Year : 1994
Month : October
Type : Thesis
Degree: BS
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The performance of an activated carbon adsorption column from coconut shell was evaluated in a laboratory scale for the decolorization of wastewater from textile mill. Initially the coconut shell was carbonized at 700°C with an average percent yield of 26.42%. Then the charcoal was activated using a designed and fabricated reactor at 800°C for 60 minutes with an average percent yield of 66.45%. The iodine number of the produced activated carbon was 894.64 mgl/gram carbon.

The laboratory investigation was composed of two parts, the adsorption isotherm and the test columns to obtain breakthrough curves. Three adsorption isotherm equations (Langmuir, Freundlich and BET) were considered. The Langmuir equation obtained has the highest regression coefficient of 0.99615 than Freundlich and BET. Langmuir equation obtained was used in the determination of the adsorptive capacity of carbon for 90% decolorization which is 8.59 g activated carbon per liter of waste.

For column test, wastewater was loaded into three laboratory scale activated carbon adsorption column arranged in series with 0.1575 m bed depth of carbon and 3.4 cm diameter each. Color of the effluent from each column was determined certain time interval using precalibrated colorimeter.

A breakthrough curve was obtained by plotting the percent color remaining against the time in which the sample was taken. From this breakthrough curve, the breakthrough time in which the effluent color roaches the breakthrough concentration of 10% of the influent color can be obtained for each column. Plotting breakthrough time against the bed depth of each column, a linear equation of regression coefficient equal to 0.9961 was obtained which is a rearranged Bohart’s and Adam’s Equation.

The Bohart’s and Adam’s equation obtained can be used in determining the critical bed depth, the service time of the column, the bed depth of carbon required for a certain volumetric flow rate and the reactivation time of the first column if arranged in series. This equation can only be strictly applied for the same linear flow rate of 0.1980 m/min and other conditions in which it was derived.

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