Cadmium removal from water using thiolactic acid-modified titanium dioxide nanoparticles

L. R. Skubal, N. K. Meshkov, T. Rajh, M. Thurnauer

Research output: Contribution to journalArticlepeer-review

76 Scopus citations

Abstract

This study investigated the use of titanium dioxide (TiO2) nanoparticles to remove aqueous cadmium from simulated wastewaters. Nanosized (45 Å) colloids of anatase TiO2 were synthesized through the controlled hydrolysis of TiCl4 and their surfaces modified with the bidental chelating agent thiolactic acid (TLA). Colloids were introduced into 65 ppm cadmium-laden waters, and the suspensions were purged aerobically, anoxically with an inert gas, or by a sequential aerobic/anoxic purge. Suspensions were illuminated with 253.7 nm light. In each experiment, samples were taken from the reactor, filtered, and the filtrates analyzed by atomic absorption spectroscopy for residual cadmium. Results from the aerobic experiments exhibited minimal (approximately 10%) removal of the cadmium from solution and no reduction of the metal on either the modified or the unmodified colloid. Anoxic results were more promising, showing no cadmium reduction on the unmodified colloid but a 40% adsorption and reduction (from a +2 valence state to elemental cadmium as determined by methyl viologen tests) of cadmium on TLA-modified colloid in the presence of light. Results from the mixed atmospheric conditions fared the best and demonstrated that in the absence of light, approximately 20% of aqueous cadmium was sorbed to the modified colloid via a Freundlich adsorption isotherm. Upon illumination, greater than 90% of cadmium was removed by both adsorption and reduction processes onto the TLA-modified TiO2. These removal and reduction processes were catalytic in nature. Results from this study are significant because to date, no other research in the literature has been able to accomplish cadmium removal and reduction using TiO2.

Original languageEnglish (US)
Pages (from-to)393-397
Number of pages5
JournalJournal of Photochemistry and Photobiology A: Chemistry
Volume148
Issue number1-3
DOIs
StatePublished - May 31 2002
Externally publishedYes

Keywords

  • Cadmium
  • Photocatalysis
  • Reduction
  • Titanium dioxide

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Physics and Astronomy(all)

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