SummaryAnaerobic ammonium oxidation with an anode as the electron acceptor was realized in a dual-chamber microbial electrolysis cell (MEC). Nitrate was the main product that accounted for approximately 95% of ammonium consumed, but nitrite was also detectable. Using 16S ribosomal RNA analysis, we found that the microbial community attached to the electrode was dominated by Nitrosomonas europaea (40.3%) and the genus Empedobacter (34.7%), but no anammox bacteria were detected. Nitrosomonas europaea was shown to be necessary with an inhibition assay using allylthiourea. Certain soluble metabolites were found to have an important effect on the current production. These results show that there are many ways to oxidize ammonium biologically.

More attention has been given to studies on the synchronous enhancement of the light-to-thermal conversion capacity and thermal conductivity of polymer phase-change material (PCM) to conserve solar energy. Here, commonly used PEG PCM was encapsulated by graphene nanoplatelets (GNPs) and single-walled carbon nanotubes (SWCNs), while polymer composites were simultaneously obtained. The 3D interconnected SWCNs and GNPs equipped PEG with (1) shape stability and thermal durability, (2) negligible change in energy storage density, (3) record-high thermal conductivity, and (4) favorable solar-to-thermal conversion capability as expected. In clear contrast to PEG/SWCNs embedded with 8 wt % SWCNs, PEG/GNPs with only 4 wt % GNPs showed comparable performance: (1) 96% of the thermal energy storage capacity of neat PEG, (2) more than 12-fold the thermal conductivity of the neat PEG, and (3) excellent solar-to-thermal conversion efficiency of 86%. We quantify these differences for the first time. More importantly, the involved microstructure–performance mechanism of these photodriven composite PCMs has been discussed and visualized for the first time. The superior comprehensive performance of PEG/GNPs compared to that of PEG/SWCNs could be attributed to the filler dimension difference, which follows the trend of 1D < 2D.

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