Nano Today
ReviewNanomaterials in pollution trace detection and environmental improvement
Introduction
The environmental security has been threatened by a broad range of chemical contaminants produced by industry and agriculture activities, which include inorganic gases (carbon monoxide, carbon dioxide, sulfur dioxide, nitric oxide, etc.), volatile and semi-volatile organic hydrocarbons, aldehydes and ketones, heavy metals (Hg(II), Cr (VI), Cd(II), As(III), As(V), Pb(II), etc.) and POPs (aldrin, dieldvin, endrin, toxaphene, heptachlor (DDT), hexachlorobenzene, chlordane, mirex, polychlorinated biphenyls (PCB), dioxins, furans, etc.).
People are all routinely exposed to a broad range of pollutants that are present within the environment, including pollutants within the air we breathe, the food we eat, and the water we drink. Some trace POPs and heavy metals are seriously harmful to human health. Therefore, in situ trace detecting and accurately, rapidly and quantitatively measuring these toxic substances in air, water and soil are very important. Up to now, although large size and modernization expensive equipments in labs can be used to analyze POPs and heavy metals etc., taking pollutant samples in the local region cannot characterize often the practice state of pollutants within the large region and rapid detection of pollutants is difficult to be realized. Development of inexpensive, sensitive, flexible, and portable monitoring devices is an urgent task. Detecting and removal of pollutants are tightly linked. It is extremely challenging to develop new treatment methods and effective removal techniques of pollutants. Unique physical and chemical properties of nanomaterials have a tremendous potential for designing detecting devices and providing pollutant removal.
Nanomaterials are attractive because of their unique chemical and physical properties (size, composition, conductivity, magnetism, mechanical strength, light absorbing, and emitting properties) [1], [2]. The study on trace detecting and treatment of pollutants etc. has made extended progress. By utilizing nanomaterials, trace detection sensors have shown great promise for detection of chemical markers of pollutants because the materials are used to either capture the marker or amplify the signal associated with detection [3], [4]. Both of these capabilities are important for trace level detection. These capabilities are hardly to be realized by using conventional materials. The wavelength and intensity of SPR peaks can be modulated via shapes and structures of nanomaterials, such as hollow spheres, core-shell structures, the aspect ratio of nanotubes or nanowires, etc. [5]. The detection by using SPR presented high sensitivity with a reduced measurement time. It was possible to measure trace POPs, such as PCB, at a ppb level. Surface-enhanced Raman scattering (SERS) has great potential as an analytical technique [6]. Nanostructured novel metal materials can make the target molecules of pollutants concentrate within the zone of electromagnetic enhancement that facilitate SERS detection and molecular identification, even very weak Raman signal can be recognized. Nanoparticles such as colloidal metals and inorganic crystals (e.g. quantum dots (QDs)) are currently being used as labels, markers, or probes for detection of pollutant molecules [7]. The most common approaches use colloidal gold or QDs as the electroactive species or optical sensitive substance. QDs can either absorb light energy or emit photons at characteristic wavelengths. These optical properties can be modulated via size change and QD structure change, such as core-shell structure QDs, the surface-modified QDs in a broad range of visible light wavelength. In most cases, QDs are conjugated to some special substances to capture target pollutants of interest. Through analyzing the change of intensity and wavelength of fluorescence or absorption peaks, trace pollutant detection can be realized. Using nanostructured electrodes or nanomaterials-modified electrodes to capture heavy metals, trace pollutants are measured by electrochemical routes. It is noted that for POPs measurements, the electrodes modified by antibodies or other substances, for example, enzyme, etc., are necessary and important. According to different POPs, the types of the antibodies or enzymes should be reasonably selected. This is the key for successful detection of trace POPs.
Pollutant treatments are challenges in clean water and soil. Nanomaterials have many excellent properties, such as strong adsorption, enhanced redox and photocatalytic properties etc. Advances in nanomaterials science and technology are providing unprecedented opportunities to treat pollutants in water and soil. It is emphasized that during treating pollutants by using nanomaterials, the following four precedent conditions should be met: (1) environment security, (2) reuse of treatment agents, (3) low cost and (4) high treatment efficiency. The highlights of study and development for pollutant treatments are design, synthesis and application of nanosorbents, optical nanocatalysts, redox active nanoparticles and nanostructures. Nanosorbents include immobilization of zero-valent nanoparticles on porous carriers to form composites, micro-/nano-multiwalled carbon nanotube arrays, zeolites, montmorillonite, kaolinite, diatomite, illite, etc. Optical nanocatalysts include N- or C-doped TiO2 nanoparticles, porous silica modified by nano-TiO2 particles, porous ZnO nanobelts, nano-Cu2O composites etc. Redox active agents include hierarchically structured metal oxides such as, iron oxides, Mn3O4, CeO2, Co3O4, etc.
In this article, an over view on recent progress in trace pollutant detection and treatment in water and soil is described. This review will have two main parts: the first for trace pollutant detection by using nanomaterials and nanotechnology, and the second for pollutant (POPs and heavy metals) treatments.
Section snippets
Surface-enhanced Raman scattering
SERS has great potential as an analytical technique based on the unique molecular signals presented even by structurally similar analyte species and the minimal interference of scattering from water when sampling in aqueous environments [8]. The SERS technique is able to detect and distinguish a wide variety of analytes on the minute time scale without interference from a common environmental contaminant. Hyanes and coworkers [9], [10] studied systematically trace polycyclic aromatic
Adsorption
Conventional water treatment methods including bio-sand, coagulation-flocculation, reverse osmosis, distillation, and adsorptive filtration through ion exchange resins, active alumina, or iron oxide cannot effectively remove all the heavy metal ions. Materials that have either ion exchange sites or lattice vacancies are expected to be able to efficiently remove heavy metal ions from water. Following features are needed for the ideal materials for the removal of heavy metal ions from water: (i)
Conclusions
Nanomaterials offer a tremendous potential due to their large surface area for a given volume, high surface activity, and strong adsorption ability. Nanomaterials are the nucleus for the design of the detection devices and they are of great aid to improve the detection limit. This is difficult to be realized by using traditional materials. Based on detection techniques of surface plasmon resonance, surface-enhanced Raman effect, fluorescent emission and absorption of quantum dots, and
Acknowledgments
This work was financially supported by the National Basic Research Program of China (Grant No. 2007CB936601). The authors would like to express their thanks to Prof. Jimei Mou and Guowen Meng for the technical help.
Lide Zhang graduated from Beijing University in 1964. From 1979 to 1980, he was a visiting scholar in Institute of Metal Research, Max-Plank Society in Germany. From 1987, he began to research on nanomaterials and nanostructures, and founded a Nanomaterial And Nanostructure Laboratory and an Application And Development Center Of Nanomaterials in the Institute of Solid State Physics, Chinese Academy of Sciences. He was appointed as the chief scientist of National Major Project of Fundamental
References (143)
- et al.
Anal. Chim. Acta
(2007) - et al.
Vib. Spectrosc.
(2009) - et al.
Anal. Chim. Acta
(2005) - et al.
Anal. Chim. Acta
(2001) - et al.
Anal. Chim. Acta
(2006) - et al.
Talanta
(2006) - et al.
J. Electroanal. Chem.
(2004) - et al.
Biosens. Bioelectron.
(2007) - et al.
Anal. Chim. Acta
(2006) - et al.
Sens. Actuators B
(2007)
Biosens. Bioelectron.
Sens. Actuators B
Electrochem. Commun.
Electrochem. Commun.
Talanta
Electrochem. Commun.
J. Hazard. Mater.
Appl. Geochem.
Colloid Surf. A
J. Hazard. Mater.
Carbon
J. Colloid Interface Sci.
J. Hazard. Mater.
J. Hazard. Mater.
Environ. Pollut.
Appl. Catal. B: Environ.
J. Hazard. Mater.
Surf. Sci.
J. Nanosci. Nanotechnol.
J. Mater. Sci. Technol.
J. Nanosci. Nanotechnol.
Acc. Chem. Res.
Anal. Bioanal. Chem.
J. Am. Chem. Soc.
Raman Spectroscopy for Chemical Analysis
Anal. Bioanal. Chem.
J. Appl. Phys.
J. Phys. Chem.
J. Chem. Phys.
Phys. Rev. Lett.
Phys. Rev. Lett.
Cryst. Growth. Des.
J. Phys. Chem. B
J. Phys. Chem. B
J. Phys. Chem. B
Langmuir
J. Phys. Chem. B
J. Appl. Phys.
Environ. Sci. Technol.
Science
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Lide Zhang graduated from Beijing University in 1964. From 1979 to 1980, he was a visiting scholar in Institute of Metal Research, Max-Plank Society in Germany. From 1987, he began to research on nanomaterials and nanostructures, and founded a Nanomaterial And Nanostructure Laboratory and an Application And Development Center Of Nanomaterials in the Institute of Solid State Physics, Chinese Academy of Sciences. He was appointed as the chief scientist of National Major Project of Fundamental Research (973 Project) on Nanomaterials and Nanostructures from 1999 to 2004. In 2006, he was awarded the Second Class of National Natural Science on the Preparation Study of One-Dimensional Nanowires and Their Ordered Arrays. He has authored and co-authored more than 370 original papers and these papers have been cited over 11,000 times. He has also authored and edited 12 scientific references and books.
Ming Fang completed his Ph.D. thesis from Institute of Solid State Physics, Chinese Academy of Sciences in 2008 under the supervision of Professor Lide Zhang. After then, he worked in the Institute of Solid State Physics, Chinese Academy of Sciences as an assistant professor. He has authored and co-authored over 20 peer-reviewed journal publications and Chinese invention patents. His current research topic is the controlled fabrication of nanomaterials with novel performance, especially those that can be used in degradation of organic pollutants.