Carbon nanocages as heavy metal ion adsorbents

• Published in: Desalination 2011-10, Vol.280 (1), p.87-94
• Main Authors: Burke, David M., O'Byrne, Justin P., Fleming, Peter G., Borah, Dipu, Morris, Michael A., Holmes, Justin D.
• Format: Article
• Language: English
• Subjects: Adsorbents; Adsorption; Applied sciences; Carbon; Catalysis; Catalytic reactions; Chemical engineering; Chemistry; Deposition; Drinking water and swimming-pool water. Desalination; Exact sciences and technology; General and physical chemistry; General purification processes; Lead ions; Mathematical models; Nanocages; Nanocomposites; Nanomaterials; Nanostructure; Pollution; Reactors; Remediation; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Waste water; Wastewaters; Water treatment and pollution
• ISSN: 0011-9164; 1873-4464
• DOI: 10.1016/j.desal.2011.06.053

Heavy metal ion contamination in drinking water poses a major risk to human health, whilst contamination in wastewater streams can cause damage to the wider environment. In this study carbon nanocages, synthesised using a supercritical fluid deposition method, were examined as adsorbents of Pb 2+ ions from aqueous solutions. Through careful selection of the catalyst and the carbon deposition temperature and pressure, high yields of nanocages with surface areas up to 1175 m 2 g −1 were synthesised. These high surface area materials were subsequently tested for their ability to absorb Pb 2+ ions, as a function of pH, from simulated wastewater. The nanocages were found to be effective at removing the Pb 2+ ions at levels of 11.1 mg g −1, compared to 7.6 mg g −1 for commercially available activated carbon. The kinetics of metal ion adsorption by the nanocages and activated carbon can be described by a pseudo-second-order kinetics model, with a rate coefficient ( k 2) of 4.8 × 10 2 g mg −1 min −1. ► Synthesis of high surface area carbon nanocages (CNCs). ► Optimisation of the CNC production process to generate high surface areas and increase yields. ► CNCs exhibit excellent dispersibility in aqueous solution. ► CNCs permit fast transport of aqueous media through a fix bed system. ► CNCs and AC were tested for the removal of lead ions (Pb 2+) from simulated wastewater conditions.