Study of adsorption capacity of commercial activated carbon versus storage time

Abstract

The pulverized activated carbon, when well packed and stored, doesn’t have either a regulated or approved shelf life. In general, this expiration date is determined based on the established requirements coming from the manufacturer itself and it is directly related to an overestimation of the time that the product is held in the customer storage location until its use. In this analysis, the research has assessed the efficiency of the moistened and the dry activated carbon powder, relating parameters of adsorption capacity (numbers of iodine and humidity) in these materials with time information. The charcoals containing alkaline surface didn’t exhibit a variation in the parameters evaluated along the storage time, since they didn’t feature statistical significance, once the F _regression < F _critical and the rate of p > 0.05, both for dry and wet basis. From the viewed acid carbons (with corrected pH), there was only one which got sensitive to moisture and iodine adsorptions over time. From the equation of the line originated by analysis of regression for this charcoal, the following correlation was obtained: Iodine Index=824-0.370 x days, showing that the storage time for the carbon was equal to 605 days, assuring that the right value of iodine index is equivalent to the limit of 600 mg I₂ g^-1 carbon.

Keywords:
Charcoal; Iodine index; Moisture; Expiration date