Speaker: Jorge Gardea-Torresdey

THE BREN SCHOOL OF Environmental Science & Management
at the University of California, Santa Barbara


The University of California

Center for the Environmental Implications of Nanotechnology


Jorge Gardea-Torresdey


Department of Chemistry

University of Texas, El Paso

Thursday, February 12, 2009

11:00 a.m. – 12:00 p.m.

Bren Hall Dean’s Conference Room (2436)


"The Impact of Stabilized and Nonstabilized Nickel Hydroxide Nanoparticles

on Mesquite Plants"


Hosted by

Bren Professor Arturo Keller



Nanomaterials are of particular interest in environmental chemistry due to their multiple applications and unknown impact on living organisms. In this study, mesquite (Prosopis sp.) plants were treated with 0.01 g, 0.05 g, and 0.10 g of three types of Ni(OH)2 nanoparticles in hydroponics. The nanoparticles were synthesized titrating an aqueous solution of Ni(NO3)2 with sodium hydroxide. The first set included non-stabilized Ni(OH)2 nanoparticles of an average size of 8.7 nm. The second set was nanoparticles with an average size of 0.9 nm stabilized with sodium citrate after the titration. The third set consisted of nanoparticles with an average size of 2.5 nm stabilized with sodium citrate before the precipitation of the Ni(OH)2. The mesquite plants showed little to no effects on the root and shoot elongation or chlorophyll production. The ICP-OES determinations showed that plants treated with 0.10 g of nonstabilized nanoparticles (8.7 nm) had 38182, 1484, and 803 mg/kg DW of Ni in roots, stems, and leaves, respectively. Plants treated with 0.10 g, of nanoparticles stabilized before precipitation (2.5 nm) had concentrations of 11431, 1021, and 400 mg/kg in roots, stems and leaves, respectively.  While plants treated with 0.10 g of nanoparticles stabilized after titration (0.9 nm) showed nickel concentrations of 12988, 642, and 315 mg/kg in roots, stems, and leaves, respectively. The XAS analysis showed the presence of Ni(OH)2 nanoparticles in roots and stems of plants treated with nonstabilized (8.7 nm) nanoparticles; while a nickel(II) organic acid type complex was observed in leaves. However, all plants treated with stabilized nanoparticles (0.9 nm and 2.5 nm) show Ni(OH)2 nanoparticles in roots and a nickel(II) organic acid complex in stems and leaves.


Jorge Gardea-Torresdey is Chair and Dudley Professor of Chemistry and Environmental Science and Engineering in the Chemistry Department at the University of Texas at El Paso. He earned his PhD in analytical chemistry at New Mexico State University. His internationally recognized scientific achievements include research in which he used alfalfa plants to harvest nanoparticles of gold. The American Microchemical Society has awarded Gardea-Torresdey with the prestigious 2004 A. A. Benedetti-Pichler Award for significant achievements in microchemistry. Gardea-Torresdeyholds five U.S. patents for environmental remediationhas authored or co-authored more than 170 refereed publications and book chapters, and. Current research projects are funded by the National Institutes of Health, the Department of Energy, the Department of Defense, the Environmental Protection Agency, the National Science Foundation, and the U.S. Air Force. He serves on the editorial boards of the Microchemical Journal; the Journal of Hazardous Materials; Applied Spectroscopy Reviews; Environmental Toxicology and Chemistry; Advances in Environmental Research; Scientiae Naturae; and Ciencia en la Frontera.



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