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Journal of Nanoparticle Research

, 16:2813

First Online: 23 December 2014Received: 13 May 2014Accepted: 10 December 2014


In the current work carbon-supported nanoscale zero-valent iron particles CS nZVI, synthesised by the vacuum heat treatment of ferric citrate trihydrate absorbed onto carbon black, have been tested for the removal of uranium U from natural and synthetic waters. Two types of CS nZVI were tested, one vacuum annealed at 600 °C for 4 h and the other vacuum annealed at 700 °C for 4 h, with their U removal behaviour compared to nZVI synthesised via the reduction of ferrous iron using sodium borohydride. The batch systems were analysed over a 28-day reaction period during which the liquid and nanoparticulate solids were periodically analysed to determine chemical evolution of the solutions and particulates. Results demonstrate a well-defined difference between the two types of CS nZVI, with greater U removal exhibited by the nanomaterial synthesised at 700 °C. The mechanism has been attributed to the CS nZVI synthesised at 700 °C exhibiting i a greater proportion of surface oxide Fe to Fe 0.34 compared to 0.28; ii a greater conversion of ferric citrate trihydrate 2FeC6H5O7·H2O to Fe; and iii a larger surface area 108.67 compared to 88.61 m g. Lower maximum U uptake was recorded for both types of CS nZVI in comparison with the borohydride-reduced nZVI. A lower decrease in solution Eh and DO was also recorded, indicating that less chemical reduction of U was achieved by the CS nZVI. Despite this, lower U desorption in the latter stages of the experiment >7 days was recorded for the CS nZVI synthesised at 700 °C, indicating that carbon black in the CS nZVI is likely to have contributed towards U sorption and retention. Overall, it can be stated that the borohydride-reduced nZVI were significantly more effective than CS nZVI for U removal over relatively short timescales e.g. <48 h, however, they were more susceptible to U desorption over extended time periods.

KeywordsNanoparticles Zero-valent iron Carbon black Uranium Remediation  Download fulltext PDF

Autor: Richard A. Crane - Thomas Scott



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