DOI: https://doi.org/10.55373/mjchem.v24i2.110

Keywords: Eggshell membrane; free fatty acid; used cooking oil; cationic and anionic dyes

Abstract

In this study, eggshell membrane (ESM) was functionalized with free fatty acids (FFAs) from new and used palm cooking oil to produce ESM@FFAs-NCO and ESM@FFAs-UCO respectively for use as adsorbents for cationic and anionic dyes. The synthesis protocol was optimized, and it was found that the optimum time for the reaction of ESM with FFAs was 15 minutes and the optimum mass ratio of ESM to FFAs was 1:4. Both adsorbents were characterized using SEM and FTIR. The functionalized ESM was found to have a more extensive microporous network structure than that of non-functionalized ESM. FTIR analysis confirmed the successful attachment of FFAs onto the surface of ESM in both ESM@FFAs-NCO and ESM@FFAs-UCO. It was found that the adsorption capability of the adsorbents towards Alizarin Red from worst to best followed the order: ESM < ESM@FFAs-NCO < ESM@FFAs-UCO. Functionalized ESM produced a synergistic effect due to hydrogen bonding and hydrophobic interactions when adsorbing dyes on its active sites. A higher dye removal efficiency was obtained when using ESM@FFAs-UCO due to its greater long alkyl chain content, giving better hydrophobic behaviour. Therefore, ESM@FFAs-UCO was investigated as an adsorbent for other organic dyes such as Rhodamine B, Chicago sky blue, and Remazol dye. The removal percentages obtained were 87.83% for Alizarin Red, 84.59% for Remazol, 78.34% for Rhodamine B and 65.68% for Chicago Sky Blue.