In this study, reverse electrodialysis power generation using an anisotropic anodic aluminum oxide membrane with nanopores of two different pore diameters is proposed and experimentally investigated for the first time. A number of experiments were carried out for various combinations of concentrations to show that the anisotropic anodic aluminum oxide membrane is superior to the conventional isotropic membrane. As a result, the highest power density that was measured from the anisotropic membrane was 15.0 mW/m2, and it was 7.2 times higher than that from the isotropic membrane. The reasons why the anisotropic membrane is superior to the isotropic membrane are explained in detail. The experiments on the anisotropic membranes with various active layer lengths and pore diameters were also conducted for exploring the effects of these engineering parameters on the power generation performance. As a result, it was shown that the length of the active layer is a more important engineering parameter than the pore diameter of the active layer. Additionally, it was also shown that a low concentration solution should be brought into contact with the active layer side of the membrane whenever an anisotropic membrane is used for reverse electrodialysis.
than one-twentieth of the support layer length. As a result, the power density of the anisotropic membrane is much greater than that of the isotropic membrane. The experiments on the anisotropic layemr leemngbtrha.nAesswaitrhe svualrito,utsh aecptiovwel earyderelnensigtythosfa nthde paonreis doitarmopeitcersm wemerbe rcaonneduisctmedu. cIth wgarsesahteorwtnh athnatthat of the length of the active layer is a more important engineering parameter than the nanopore diameter of the active layer. Additionally, it was shown that a low concentration solution should be brought into contact with the active layer side of the membrane whenever an anisotropic membrane is used for reverse electrodialysis. shown that a low concentration solution should be brought into contact with the active layer side of the membrane whenever an anisotropic membrane is used for reverse electrodialysis. writing\u2014review and editing, D.-K.K. Author Contributions: Investigation, Y.L., H.J.K., and D.-K.K. writing\u2014original draft preparation, D.-K.K., Funding: This research was supported by the Nano-Material Technology Development Program through the National Research Foundation of Korea (NRF) and funded by theMinistry of Science and ICT (NRF-2011-Funding: This research was supported by the Nano-Material Technology Development Program through the 0030285). National Research Foundation of Korea (NRF) and funded by the Ministry of Science and ICT (NRF-2011-0030285). Conflicts of Interest: The authors declare no conflict of interest. The funders had no role in the design of the Conflicts of Interest: The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publishpublish the resthe results.ults.
