Attachments ( 5 files ):
  • 5 image files

Nanomaterials: Small Things That Make Things Become Different

In recent years, our society has been dealing with one of the most formidable challenges in maintaining a good quality of water supply due to the potential seepage of landfill leachate (Figure 1) (Kurniawan et al., 2006a).1.jpg

Figure 1. Leachate from  a local landfill in China (Illustration courtesy from Guo J).

As a result, the groundwater in several sites that are close to open dumps might have been contaminated (Kurniawan et al., 2006b. Consequently, the presence of emerging contaminants such as endocrine-disrupting compounds (EDC) in such highly contaminated wastewater has emerged as one of the most serious environmental concerns worldwide. 

Various environmental technologies have been employed to remove refractory compounds from landfill leachate. However, to date neither type of existing conventional treatment is universally applicable and/or highly effective (Kurniawan et al., 2006c). This suggests the need for technological advancements in water treatment to benefit people in many parts of the world.

The diverse applications of nanotechnology across a number of disciplines in recent years have inspired environmental researchers to address the need for an efficient and effective leachate treatment. In spite of its unproven track record in environmental applications in the past five years, researchers found that nanomaterials could play a key role in pollution control strategies. 

Several nanomaterials with size of less  than 100 nm (Figure 2) include magnetic nanoparticles, heterogeneous nanophotocatalysts, and polymeric nanoparticles. Due to their strong magnetic properties, magnetic nanomaterials act not only as an adsorbent to remove target compounds from contaminated water, but also as a magnetic element to attract and retain the nanoparticles, which can be removed from solutions. This magnetic separation, which may replace centrifuge separation technologies, has less complicated technical requirements and low regeneration cost, thus making adsorption treatment economically attractive for industrial users (Rassaei et al, 2008b) . 

2.jpg

Figure 2. How small is small? (Illustration courtesy from J.K. Evert)

Cradle-to-cradle processes in nanotechnology have also led researchers to develop a variety of photocatalytic derivatives that have nanosize such as TiO2. Due to its superb light absorbing capabilities, low cost, and non-toxicity, TiO2 has emerged as one of the most attractive nanophotocatalysts for treatment of contaminated water. In its combined application with advanced oxidation process, TiO2 in the presence of UV is capable of breaking down various refractory pollutants in leachate into relatively harmless compounds. The applications of UV to activate the TiO2 nanoparticles may facilitate green technology for environmental remediation in an aquatic environment. In addition, polymeric nanoparticles are developed as potential adsorbents for water environment difficult to be accesses (Figure 3).

3.jpg

Figure 3. Nanomaterials for Water Treatment (Pedro et al., 2003)

Likesurfactant micelles, they have amphiphilic characters. Their unique properties are attributed to individual polymers that compose the particles through graft copolymerization. When being integrated with photocatalytic degradation using TiO2 nanophotocatalyst, the applications of polymeric nanoparticles for water treatment may provide a sustainable treatment approach with potentially low energy consumption and CO2 emission, thus contributing to a green environment (Rassaei et al, 2008c) . 

Due to their ability to minimize the generation of secondary waste using less resources and capability of removing any types of pollutants from contaminated water effectively, it is anticipated that nano-adsorbents would play major roles in protecting aquatic environment in the future (Figure 4).

5.jpg

Figure 4. Attaining green environment through nanomaterials (Illustration courtesy from A.H. Kolmn)

By addressing the long-term sustainability of resources today through the applications of nanomaterials for environmental remediation, we may have a green environment tomorrow, in which human can co-exist with the nature.

Further reading:

Kurniawan, T.A., Lo, W.H. Lo, Chan, GYS. (2006a). Radicals-catalyzed oxidation for degradation of recalcitrant compounds from landfill leachate. Chemical Engineering Journal 125(1): 35-57.
Kurniawan, T.A., Lo, W.H. Lo, Chan, GYS. (2006b). Physico-chemical treatments for removal of recalcitrant contaminants from landfill leachate. Journal of Hazardous Material 129(1-3): 80-100
Kurniawan, T.A., Lo, W.H. Lo, Chan, GYS. (2006c) Degradation of recalcitrant compounds from stabilized landfill leachate using a combination of ozone- GAC adsorption treatment. Journal of Hazardous Material 137(1): 443- 455.
Rassaei, L., Sillanpää, M., Bonné M. and Marken, F., Carbon Nanofiber – Polystyrene Composite Electrodes for Electroanalytical Processes, Electroanalysis, 19 (2007) 1461-1466.
Rassaei, L., Sillanpää, M. and Marken, F., Carbon Nanoparticle – Chitosan Thin Film Electrodes: Physisorption versus Chemisorption, Electrochim. Acta, 53 (2008a) 5732-5738.
Rassaei, L., Bonné, M., Sillanpää, M. and Marken F., Binding Site Control in a Layer- by-Layer Deposited Chitosan-Carbon Nanoparticle Film Electrode, New J. Chem., 32 (2008b) 1253-1258.
Rassaei, L., Sillanpää, M., French, R.W., Compton, R.G. and Marken, F., Arsenite Determination in the Presence of Phosphate at Electro- Aggregated Gold Nanoparticle Deposits, Electroanalysis, 20 (2008c) 1286-1292. 

Related Articles

An information resource and hub for the global water community
 
Browse
Last Contributors
Last contributors on this document:
  XWiki.beddowve   Victoria Beddow
  XWiki.tonni696390   Tonni Kurniawan