Cadmium removal from simulated groundwater using alumina nanoparticles: behaviors and mechanisms. (September 2018)

• Record Type: Journal Article
• Authors: Koju, Neel Kamal; Song, Xin; Wang, Qing; Hu, Zhihao; Colombo, Claudio
• Is Part Of: Environmental pollution. Volume 240(2018)
• Page Start: 255
• Page End: 266
• Publication Date: 2018-09
• Subjects: Cadmium -- Groundwater -- Chemisorption -- Nanoparticles -- Glycerol; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2018.04.107
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Cadmium (Cd), one of the most toxic contaminants in groundwater, can cause a severe threat to human health and ecological systems. In this study, alumina nanoparticles were synthesized and tested for high-efficiency Cd removal from simulated groundwater. Furthermore, the synthesized alumina nanoparticles were successfully modified using negatively charged glycerol, to alleviate the challenge of its low mobility in groundwater for the Cd removal. The maximum removal efficiency of both synthesized and glycerol-modified alumina nanoparticles were more than 99%. The sorption isotherm and kinetic data of both synthesized and glycerol-modified alumina nanoparticles were best fitted to the Freundlich model and the pseudo-second-order model, respectively, indicating that the sorption of Cd ions occurs on heterogeneous surfaces of both alumina nanoparticles via the chemisorption mechanism. X-ray photoelectron spectroscopy and energy dispersive X-ray analysis revealed the presence of Cd peak in both sorbents after contact with Cd. In addition, the FTIR analyses demonstrated that hydroxyl group participated in the sorption of Cd on both synthesized and glycerol-modified alumina nanoparticles, while other glycerol associated groups contributed to the removal of Cd ions by the glycerol-modified alumina nanoparticles. It was concluded that Cd removal by synthesized and glycerol-modified alumina nanoparticles were mainly due to ion exchange and electrostatic attraction, respectively. Desorption experiment suggested that both alumina nanoparticles are effective and practically significant sorbents to remediate Cd from contaminated groundwater. However, the stronger bond between Cd and glycerol-modified alumina, plus its potential of higher mobility due to the negative charge on the surface, warrant glycerol-modified alumina nanoparticles a better performance in remediating Cd contaminated groundwater than that of the synthesized alumina nanoparticles. Graphical abstract: Image 1 Highlights: Synthesized and glycerol-modified (GM) alumina are effective to reduce Cd to < 1 μg/L. Multilayer chemisorption of Cd occurs on the surface of both alumina nanoparticles. Ion exchange between H + and Cd 2+ occurs on the surface of synthesized alumina. Electrostatic attraction is the main sorption process on the surface of GM alumina. The negative charge on GM alumina surface may increase its mobility in the subsurface. Abstract : Both nanoparticles successfully reduced the Cd in simulated groundwater to below the WHO guideline limits (3 μg/L), indicating that they are fast and cost-effective Cd remediation materials.