Ming-Yin Chen1, Yun-Chih Tsai2, Chih-Fu Tseng1,3, Hong-Ping Lin 2, Hsing-Cheng Hsi 1

Graduate Institute of Environmental Engineering, National Taiwan University, Taipei 10617, Taiwan
Department of Chemistry, National Cheng-Kung University, Tainan 70101, Taiwan
Taiwan Power Research Institute, Taiwan Power Company, New Taipei City 23847, Taiwan

Received: September 21, 2019
Revised: October 14, 2019
Accepted: October 19, 2019
Download Citation: ||https://doi.org/10.4209/aaqr.2019.09.0468  

Cite this article:
Chen, M.Y., Tsai, Y.C., Tseng, C.F., Lin, H.P. and Hsi, H.C. (2019). Using Rice-husk-derived Porous Silica Modified with Recycled Cu from Industrial Wastewater and Ce to Remove Hg0 and NO from Simulated Flue Gases. Aerosol Air Qual. Res. 19: 2557-2567. https://doi.org/10.4209/aaqr.2019.09.0468


  • CuOx-CeOx/SiO2 was prepared using recycled silica modified with recycled Cu ion.
  • CuOx was highly dispersed on the surface of all tested CuOx/SiO2 samples.
  • Surface structural rearrangement after modified with Cu/Ce oxides was confirmed.
  • Cu and Ce modification was shown to successfully improve the NO removal efficiency.
  • 50%Cu/SiO2 exhibited the greatest total Hg removal at both 150°C and 250°C.


Resource-recovered CuOx-CeOx/SiO2 samples were prepared by using rice-husk-derived silica modified with recycled copper ion from panel industry wastewater for controlling Hg0 and NO emissions from simulated flue gases. By using the silicate exfoliation method for sample preparation, the presence of Cu and Ce oxides could increase the specific surface area (SBET) of SiO2. 50%Cu-10%Ce/SiO2 having the largest SBET showed significant NO removal. XRD results indicated that significant CuO diffraction peaks were not detected among all the CuOx/SiO2 samples, suggesting that CuOx was highly dispersed on the surface. SEM and TEM images showed that the uniform spherical SiO2 particles have changed into plate-like structure, further confirming the occurrence of structural rearrangement after incorporated with Cu/Ce oxides via silicate exfoliation. XPS results showed that Cu2+ and Ce4+ were the major valence states presenting in the samples. H2-TPR and NH3-TPD indicated that the 50%Cu/SiO2 and 50%Cu-10%Ce/SiO2 had greater redox ability and stronger acidity as compared to those containing smaller amounts of CuOx and CeOx. Cu and Ce modification was shown to successfully improve the NO removal efficiency. 50%Cu-10%Ce/SiO2 had the best NO conversion efficiency of 70–85% with a broad temperature window of 150–300°C. 50%Cu/SiO2 exhibited the greatest total Hg removal efficiency of 88.2% among all the tested samples at 150°C and remained almost the same removal efficiency at 250°C. These results suggest that the recycled Cu modified rice-husk-derived SiO2 is feasible for not only controlling Hg0 and NO emissions but also recovery of agricultural and industrial wastes.

Keywords: Mercury; NOx; Copper oxides; Rice-husk-derived silica; Silicate exfoliation.

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