Final Report: Advanced Nanosensors for Continuous Monitoring of Heavy Metals

EPA Grant Number: R830906
Title: Advanced Nanosensors for Continuous Monitoring of Heavy Metals
Investigators: Sadik, Omowunmi , Mulchandani, Ashok , Wang, Joseph
Institution: The State University of New York at Binghamton , New Mexico State University - Main Campus , University of California - Riverside
EPA Project Officer: Carleton, James N
Project Period: May 19, 2003 through April 18, 2006
Project Amount: $351,000
RFA: Environmental Futures Research in Nanoscale Science Engineering and Technology (2002) RFA Text |  Recipients Lists
Research Category: Nanotechnology , Safer Chemicals


The field of nanomaterials and nanotechnology encompass research areas involving the development and application of materials and devices whose structures and sizes are in the range of 1 to a few nanometers. Tailoring nanomaterials to meet specific environmental or industrial needs is an emerging area of research. The overall goal of this collaborative research is to meet the needs for innovative, advanced nanomaterials and sensors for continuous detection of priority inorganic pollutants. The objectives of this research project are to: (1) prepare, characterize, and optimize the direct incorporation of colloidal metal nanoparticles into conducting polymers using photochemical polymerization; (2) design and test novel nanosensors for the identification, detection, speciation, and quantitation of heavy metals using the nanoparticle-modified conducting polymers; and (3) fabricate disposable nanosensors using the New Mexico State University Nanofabrication facility and utilize the sensors for the analysis of metal ions from aqueous effluents.

Summary/Accomplishments (Outputs/Outcomes):

Nanostructured Conducting Polyamic Acid Membranes as Novel Electrode Materials

We have reported a new class of nanostructured electrode materials based on polyamic acid (PAA). Composite membranes of PAA and metal nanoparticles were obtained on electrodeposition of PAA solutions in either aqueous or organic media containing gold or silver salts with subsequent thermal treatment, while imidization to polyimide is prevented. Structural characterization of the films are provided using proton nuclear magnetic resonance (1H-NMR) and Fourier transform infrared (FTIR) spectroscopy, whereas the presence of metallic nanoparticles within the polymeric matrix was confirmed using scanning electron microscopy (SEM), cyclic voltammetry (CV), energy-dispersive X-ray analysis (EDX), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Results showed that a new class of organic conducting polymeric materials has been prepared.

Palladium Nanoparticles for Catalytic Reduction of Chromium (VI)

Following our success with different synthetic approaches, we have applied one of our synthetic routes for the environmental remediation of chromium (Cr). The remediation cocktails consist of palladium nanoparticles (PdNPs) as catalyst and/or formic acid/sulfur as reducing agents. Percentage removal of Cr (VI) as a function of time was monitored using UV/Vis spectroscopy at a fixed wavelength of 350 nm. Results showed that the reduction follows first order reaction kinetics with respect to initial concentrations of Cr (VI) and formic acid. The rate of Cr (VI) reduction was found to be dependent on temperature, pH, amount of PdNPs, and formic acid concentrations, with the optimum at 45° C under acidic conditions. For every 0.1 M increment in formic acid concentration, there was a corresponding 18.4 percent enhancement in the reduction rate. Consequently, it took 5 minutes for the PdNPs to catalyze the reduction of a 7.14 mM concentration of Cr (VI) at 99.8 percent efficiency. Subsequent practical application in environmental samples indicates a complete elimination of Cr (VI) from the tested soil and aqueous media. This work offers a new and safe application of nanotechnology for the reduction of high oxidation state heavy metal pollutants.

Advanced Sensors for Trace Uranium

We also have developed novel sensors for uranium using bismuth-coated carbon-fiber electrodes. The new sensor is based on the accumulation of the uranium-cupferron complex at a preplated bismuth film electrode held at –0.30 V (vs. Ag/AgCl), followed by a negatively sweeping square-wave voltammetric waveform. Factors influencing the stripping performance, including the film preparation, solution pH, cupferron concentration, adsorption potential, and time have been optimized. The resulting performance compares well with that observed for analogous measurements at mercury film electrodes. A detection limit of 0.3 μg/L is obtained in connection to a 10- minute adsorption time. The response is linear up to 50 μg/L, and the relative standard deviation at 50 μg/L uranium is 3.8 percent (n = 10; 2 minute adsorption). Potential interferences are examined. Applicability to sea water samples is demonstrated. The attractive behavior of the new mercury-free uranium sensor holds great promise for on site environmental and industrial monitoring of uranium.


Three different hybrid organic/inorganic materials incorporating nanoparticles of varying sizes have been successfully synthesized. These are (4,4’-oxydianiline)-poly-ODA, nanostructured polyamic-acid membranes, and colloidal PdNPs/formic acid/sulfur cocktails.

The new materials were extensively characterized using 1H-NMR and FTIR, SEM, CV, EDX, XRD, and XPS.

Some of the new materials have been tested for sensing and remediation. For example, nanostructured Pd-formic acid materials were tested for the rapid conversion of Cr (VI) to Cr (III). Subsequent practical application in environmental samples indicates a complete elimination of Cr (VI) from the tested soil and aqueous media.

A new mercury-free uranium sensor was developed using pre plated bismuth film electrode. This sensor holds great promise for onsite environmental and industrial monitoring of uranium.

Journal Articles on this Report : 10 Displayed | Download in RIS Format

Other project views: All 39 publications 14 publications in selected types All 10 journal articles
Type Citation Project Document Sources
Journal Article Aluoch AO, Amrute K, Sadik OA. Novel electrochemical oral biosensor for histatin. Sensor Letters 2005;3(2):161-163. R830906 (Final)
not available
Journal Article Andreescu D, Wanekaya A, Sadik OA, Wang J. Nanostructured polyamic acid membranes as novel electrode materials. Langmuir 2005;21(15):6891-6899. R830906 (2003)
R830906 (2004)
R830906 (Final)
  • Abstract from PubMed
  • Abstract: ACS Publications - abstract
  • Journal Article Andreescu D, Sadik OA. Synthesis of polyoxydianiline membranes onto gold electrodes. Journal of the Electrochemical Society 2005;152(10):E299-E307. R830906 (2004)
    R830906 (Final)
    not available
    Journal Article Andreescu S, Sadik OA. Correlation of analyte structures with biosensor responses using the detection of phenolic estrogens as a model. Analytical Chemistry 2004;76(3):552-560. R830906 (2004)
    R830906 (Final)
    not available
    Journal Article Andreescu S, Sadik OA. Advanced electrochemical sensors for cell cancer monitoring. Methods 2005;37(1):84-93. R830906 (Final)
    not available
    Journal Article Karasinski J, Andreescu S, Sadik OA, Lavine B, Vora MN. Multiarray sensors with pattern recognition for the detection, classification, and differentiation of bacteria at subspecies and strain levels. Analytical Chemistry 2005;77(24):7941-7949. R830906 (Final)
    not available
    Journal Article K’Owino IO, Omole MA, Sadik OA. Tuning the surfaces of palladium nanoparticles for the catalytic conversion of Cr(VI) to Cr(III). Journal of Environmental Monitoring 2007;9(7):657-665. R830906 (2004)
    R830906 (Final)
  • Abstract from PubMed
  • Journal Article Lin L, Thongngamdee S, Wang J, Lin Y, Sadik OA, Ly S-Y. Adsorptive stripping voltammetric measurements of trace uranium at the bismuth film electrode. Analytica Chimica Acta 2005;535(1-2):9-13. R830906 (2004)
    R830906 (Final)
    not available
    Journal Article Sadik O, Land WH, Wanekaya AK, Uematsu M, Embrechts MJ, Wong L, Pibensperger D, Volykin A. Detection and classification of organophosphate nerve agent simulants using support vector machines with multiarray sensors. Journal of Chemical Information and Computer Sciences 2004;44(2):499-507. R830906 (Final)
    not available
    Journal Article Wanekaya AK, Uematsu M, Breimer M, Sadik OA. Multicomponent analysis of alcohol vapors using integrated gas chromatography with sensor arrays. Sensors and Actuators B: Chemical 2005;110(1):41-48. R830906 (Final)
    not available

    Supplemental Keywords:

    nanomaterials, nanotechnology, environmental application, metal analysis, remediation, innovative technology, waste reduction, human health, engineering, water, sediments,, RFA, Scientific Discipline, INTERNATIONAL COOPERATION, Water, Ecosystem Protection/Environmental Exposure & Risk, POLLUTANTS/TOXICS, Sustainable Industry/Business, Environmental Chemistry, Chemicals, Arsenic, Monitoring/Modeling, Environmental Monitoring, New/Innovative technologies, Water Pollutants, Environmental Engineering, Engineering, Chemistry, & Physics, Drinking Water, nanosensors, health effects, monitoring, environmental measurement, nanotechnology, carbon nanotubes, electrically conducting polymers, micro electromechanical system, colloidal metal nanoparticles, monitoring sensor, nanocontact sensor, analytical methods, organic gas sensor, water quality, nanocrystals, drinking water contaminants, nanoengineering

    Relevant Websites: Exit Exit Exit

    Progress and Final Reports:

    Original Abstract
  • 2003 Progress Report
  • 2004 Progress Report