Preparation, characterization of a ceria loaded carbon nanotubes nanocomposites photocatalyst and degradation of azo dye Acid Orange 7

Abstract

Abstract:A ceria loaded carbon nanotubes (CeO 2 /CNTs) nanocomposites photocatalyst was prepared by chemical precipitation, and the preparation conditions were optimized using an orthogonal experiment method. HR-TEM, XRD, UV-Vis/DRS, TGA and XPS were used to characterize the photocatalyst. Nitrogen adsorption-desorption was employed to determine the BET specifi c surface area. The results indicated that the photocatalyst has no obvious impurities. CeO 2 was dispersed on the carbon nanotubes with a good loading effect and high loading effi ciency without agglomeration. The catalyst exhibits a strong ability to absorb light in the ultraviolet region and some ability to absorb light in the visible light region. The CeO 2 /CNTs nanocomposites photocatalyst was used to degrade azo dye Acid Orange 7 (40 mg/L). The optical decolorization rate was 66.58% after xenon lamp irradiation for 4 h, which is better than that of commercial CeO 2 (43.13%). The results suggested that CeO 2 loading on CNTs not only enhanced the optical decolorization rate but also accelerated the separation of CeO 2 /CNTs and water.

An eco-friendly route for template-free synthesis of high specific surface area mesoporous CeO2 powders and their adsorption for acid orange 7

“…The Table 2 shows the adsorption efficiencies from the recent literatures on CeO 2 development for the adsorption of AO7 dye. [48][49][50][51][52][53][54][55][56] By comparing the adsorption efficiencies of CeO 2 in these reported literatures, we can nd the mesoporous CeO 2 in this work showed stronger adsorption ability and achieved the absorption equilibrium more quickly, which ascribed to the higher S BET of mesoporous CeO 2 in this work. The adsorption mode of AO7 on CeO 2 could be described as a Lewis acid-base reaction between the electron-rich groups (sulfonate group, SO 3À ) of AO7 and empty 4f orbital of cerium ion on the surface of CeO 2 , which eventually formed an inner-sphere complex.…”

Anionic azo dyes removal from water using amine-functionalized cobalt–iron oxide nanoparticles: a comparative time-dependent study and structural optimization towards the removal mechanism

“… 50–53 The adsorption capacities ( q max ) shown in Table 2 indicate that our CoFeNPs as adsorbents are comparable or better even under unoptimized conditions than many other adsorbents, including magnetiteCTAB NPs 37 and alumina–polystyrene 38 for AMR removal, G. persica biomass 42 and activated carbon 43 for NBB removal, beech wood sawdust 45 and pelic soil 46 for AO7 removal, rice husk activated carbon 10 and zeolite–magnetite composite 49 for RO16 removal, and CoFe 2 O 4 -reduced graphene oxide composites 51 for AO52 removal. Considering the % dye removal data in Table 2 , our CoFeNPs adsorbents can also provide a comparable or better adsorptive sequestration of the tested dyes from water than their degradative (photo/catalytic/oxidative) removal in many cases, for example, photooxidative removal by γ-ray/H 2 O 2 for RR-P2B, 41 photocatalytic removal by solar light/CeO 2 -carbon nanotubes for AO7, 48 and oxidative-catalytic removal by H 2 O 2 /CoFe 2 O 4 for NBB and RO16. 24 Although many other adsorbents such as amine–PIM-1, 40 CTAB–flax shives, 6 CuFe 2 O 4 /activated carbon 47 and CoFe 2 O 4 /MgAl-LDO, 50 and some UV active photocatalysts such as CoFe 2 O 4 /ZnO 52 and CoFe 2 O 4 –Fe 3 O 4 ( ref.…”