Environmental remediation, sesquestration and decontamination with nanomaterials

 

Environmental remediation, sesquestration and decontamination with nanomaterials (e.g. carbon dioxide storage and conversion, catalytic reduaction of NOx)

Figure 1. Transmission FTIR spectra of CO2 adsorption on TiO2surface. Gas phase spectra have been subtracted. The bands shown in the Figure are for the adsorbed carbonate and bicarbonate species.

 

      Nanoscience and nanotechnology have potential uses in environmental applications and remediation. Storage of carbon dioxide is important not only for decreasing the emissions but also for further conversion to more useful forms. Furthermore, photocatalytic reduction of carbon dioxide into useful forms is of a great interest of the scientific community all over the globe towards a sustainable world. In Grassian group laboratories we are investigating uptake and conversion of carbon dioxide on nanomaterial TiO2 and CeO2. In these studies Transmission FTIR spectroscopy and DRIFT spectroscopy methods are used as a main research tools.

Furthermore, In collaboration with Professor Sarah Larsen (Chemistry), we have studied both the uptake of CO2 and the removal of NOx (deNOx) using nanocrystalline zeolites as a  deNOx material. Nitrogen oxides (NOx, x = 1, 2) are mainly emitted from the combustion of fossil fuels and leads to cause a range of health and environmental effects from adverse respiratory problems to acid rain. Nitrogen oxides In the case of the environmental remediation of NOx, nanocrystalline zeolites have been shown to be more effective in the selective catalytic reduction (SCR) of NOx with urea. Scheme below shows the mechanism for this reaction which involves NOx storage in the internal pores and reaction on the external surface of the nanoparticles.

 

 

 

 

Scheme. (a) SEM image of nanocrystalline NaY zeolite (scale bar = 100 nm), (b) a nanocrystalline zeolite particle with a crystal size of 23 nm, and (c) supercages (cycles) of zeolite Y interconnected to each other. The internal surface of nanocrystalline zeolite provides sites for NOx storage (as NO2- and NO3-) and minority of the SCR reactions, the external surface provides sites for additional NOx storage (as NO3-) and majority of the SCR reactions. Nanocrystalline alkali zeolites are classified as improved SCR catalysts.