Turning Waste into Solutions: Activated Carbons from Shrimp Shell for Nicotine Adsorption in Aqueous Phase

In this study, removal of nicotine, highly toxic and persistent environmental contaminant, was successfully conducted using activated carbons prepared via chemical activation with KOH from shrimp shell, a byproduct of the food industry. The activation process yielded activated carbons with an exceptionally developed porous texture, exhibiting, in the best case, a surface area of nearly 2000 m²/g and a surface enriched with diverse oxygenated functional groups, as confirmed by XPS and FTIR analyses. Nicotine adsorption studies demonstrated that the adsorption process was more favorable at near-neutral pH values (pH = 8) and higher temperatures. Kinetic and thermodynamic analyses, combined with material characterization, revealed that the adsorption process is governed by both physical and chemical interactions between the adsorbate and the adsorbent, being overall spontaneous and endothermic. The Sips isotherm model closely fits the adsorption data, highlighting the heterogeneity of the activated carbon surface. Under these conditions, adsorption was studied at three different temperatures, with the highest temperature (45 °C) exhibiting the most significant adsorption capacity, slightly below 500 mg/g. In addition, column adsorption tests demonstrated the high efficiency of activated carbons in nicotine removal, making shrimp head shells a promising carbon precursor for use as a raw material in preparing activated carbons for use as nicotine adsorbents for industry.