After the Fukushima Daiichi Nuclear Power Plant accident, a variety of radionuclides has been treated by Advanced Liquid Processing System including different adsorbents. This work aims to synthesize layered double hydroxide (LDH)/different carbon materials composites for simultaneous adsorption of radioactive anion and cation, where 79 SeO 4 2- and 90 Sr 2+ have been selected as targets for removal. As carbon materials, carbon-dot and graphene oxide (GO) were synthesized to modify LDH, in which the presence of carboxylic groups was confirmed by FTIR. TEM observation revealed the sizes of C-dot and LDH particles are 3-5 nm and around 100 nm, respectively, while the size of GO has been reported 1-2 mm. Simultaneous adsorption of SeO 4 2- and Sr 2+ was achieved in both composites using surrogates, though ion-exchange of SeO 4 2- with NO 3 - in LDH and complexation of Sr 2+ with carboxyl group in carbon materials. Comparable adsorption capacities of SeO 4 2- was observed on both composites. However, Sr 2+ adsorption capacities were much larger in LDH/GO than LDH/C-dot in any cases of different carbon contents. In addition, Sr 2+ adsorption capacities in mmol/g-GO were much larger in LDH/GO composites than pure GO. Zeta potential of LDH/GO was +31.0 mV closer to LDH, while that of LDH-C-dot was -16.4 mV closer to C-dot. These observation suggests there is a clear contrast between two composites. That is, the composite of LDH/GO consists of coverage of larger sheets of GO with smaller sheets of LDH, while the composite of LDH/C-dot consists of coverage of larger sheets of LDH with nano-sized C-dot. Accordingly it is promising to customize the ratio of LDH/GO in the composite considering the different radioactive waste water compositions to treat in various stages.
|Publication status||Published - Jan 1 2017|
|Event||14th International Symposium on East Asian Resources Recycling Technology, EARTH 2017 - Sapporo, Hokkaido, Japan|
Duration: Sept 26 2017 → Sept 29 2017
|Conference||14th International Symposium on East Asian Resources Recycling Technology, EARTH 2017|
|Period||9/26/17 → 9/29/17|
All Science Journal Classification (ASJC) codes
- Environmental Science(all)