Enhanced mercury ion adsorption by amine-modified activated carbon

• Published in: Journal of hazardous materials Vol. 166; no. 2; pp. 866 - 872
• Main Authors: Zhu, Jianzhong, Yang, John, Deng, Baolin
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 30.07.2009; Elsevier
• Subjects: Activated carbon; Adsorption; Amines - chemistry; Applied sciences; APTES; Charcoal - chemistry; Chemical engineering; Exact sciences and technology; Hazardous Substances - isolation & purification; Hydrogen-Ion Concentration; Kinetics; Mercury - isolation & purification; Mercury adsorption; Pollution; Surface modification; Surface Properties; Water Pollutants, Chemical - isolation & purification; Surface modification; APTES; Mercury adsorption; Activated carbon; Scanning electron microscopy; Ligand; Potentiometry; Dispersive spectrometry; Sediments; Heavy metal; Adsorption; Surface properties; pH; Kinetics; Fourier-transformed infrared spectrometry; Mercury
• ISSN: 0304-3894; 1873-3336; 1873-3336
• DOI: 10.1016/j.jhazmat.2008.11.095

Mercury (Hg) is one of the most toxic metals found in water and sediments. In an effort to develop an effective adsorbent for aqueous Hg removal, activated carbon (AC) was modified with an amino-terminated organosilicon (3-aminopropyltriethoxysilane, APTES). Surface properties of the APTES-modified AC (MAC) were characterized by the scanning electron microscopy in conjunction with the energy-dispersive spectroscopy (SEM-EDS), the Fourier transform infrared spectroscopy (FT-IR), and potentiometry. The impacts of solvent, APTES concentration, reactive time and temperature on the surface modification were evaluated. The aqueous Hg adsorptive kinetics and capacity were also determined. Results demonstrated that the strong Hg-binding amine ligands were effectively introduced onto the AC surfaces through the silanol reaction between carbon surface functional groups (–COOH, –COH) and APTES molecules. The modification lowered the pH at the point of zero charge (pH pzc) to 4.54 from 9.6, favoring cation adsorption. MAC presented a faster rate of the Hg (II) adsorption and more than double adsorptive capacity as compared with AC.