Characterization and Optimization of Crustacean Shell-derived Activated Carbon for Wastewater Treatment Applications

Comparative studies of the Surface Chemistry, morphology, and physicochemical properties of crustacean shells activated chemically using acid (H2SO4) and base (KOH) were investigated. Following the activation, samples of acid and base activated Periwinkle shells (PSAAC and PSBAC), Clam shells (CSAAC and CSBAC), whelk shells (WSAAC and WSBAC), and a 1:1 Clam/Whelk composite Shells (CWSAAC and CWSBAC) were obtained. The properties investigated were moisture content, specific gravity, surface area, porosity, ash content, carbon yield, fixed carbon, FTIR, and SEM-EDX. The findings demonstrate the good physicochemical qualities of activated carbons made from Periwinkle, Clams, Whelks, and a Clam/Whelk composite by acid and base activation for the treatment of wastewater. Among them, the Clam acid-activated carbon (CSAAC) demonstrated exceptional physicochemical qualities with a surface area of 1277 m2/g, moisture content of 1.4%, ash content of 8.3%, carbon yield of 87%, and fixed carbon of 63.7%. On the other hand, the Clam Shell Base-Activated Carbon (CSBAC) exhibited a greater porosity of 0.88, indicating that it could be a more efficient option for adsorption in wastewater treatment. Both base- and acid-activated carbons generally showed modest ash contents; however, at 12.3%, Whelk Shell Base-Activated Carbon (WSBAC) had the highest ash concentration.

The bulk densities of acid- and base-activated carbons were almost identical. The bulk densities, from highest to lowest, were CSBAC > CSAAC > CWSBAC > CWSAAC > PSBAC > PSAAC > WSBAC > WSAAC, with values ranging from 0.687 g/cm³ to 0.454 g/cm³. The porosity of the samples, ranked in descending order, was CSBAC > PSBAC > CSAAC > CWSAAC > PSAAC = CWSBAC > WSAAC > WSBAC, with values from 0.88 to 0.59.

FTIR and SEM-EDX indicated that all samples were successfully converted to activated carbon. The results of this study demonstrate that it is possible to chemically activate crustacean shells using either an acid or a base without sacrificing the effectiveness of the activated sample that is produced, which can be used to remove adsorbates from wastewater samples. As a result, the selection of activation is widened since the natural abundance of precursors exists.