Efficacious Removal of Trace Mercury from Honeysuckle Water Decoction Using Multifunctional Mesoporous Carbon

A mesoporous carbon (PC-2) obtained by using sucrose as a carbon source and urea as a nitrogen source has been used to remove trace mercury (Hg) from honeysuckle water decoction with high efficiency. The morphology, chemical composition, and pore structure of PC-2 have been characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and Brunauer-Emmett-Teller (BET). The results show that the specific surface area of PC-2 with the -NH₂ functional is 1077.44 m²·g^-1, and the mesoporous pore size is mainly around 2.8 nm. The investigation of the relationship between the adsorption performance and the structure of PC-2 indicates that the pore size and the chemical composition of carbons are significantly correlated with adsorption performance of mercury in water and honeysuckle water decoction. PC-2 has high efficiency approximated 100% for mercury from aqueous solutions. The pseudo-second-order kinetic model and the Freundlich model could better fit the adsorption process of Hg(II) onto PC-2. The process was dominated by chemical adsorption. Meanwhile, the adsorption behavior and the influence on the medicinal components (chlorogenic acid) of mercury removal in honeysuckle water decoction were determined by high performance liquid chromatography (HPLC). Results suggest that PC-2 has high efficiency approximated 66% for mercury from honeysuckle water decoction under optimal adsorption conditions, without affecting its active ingredients (chlorogenic acid). Therefore, PC-2 can potentially be used for adsorption of mercury in honeysuckle water decoction.