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Recycling Al is crucial to reduce the energy and environmental costs of Al manufacturing; however, the reclamation efficiency of high-quality Al from Al alloys is limited by the co-deposition of impurities during the electrorefining process. To address this issue, the anodic dissolution behavior of metallurgical structures within various Al-Mn binary alloys in 1-ethyl-3-methyl-imidazolium chloride-AlCl 3 ionic liquid was investigated. During the constant-potential electrolysis of Al-1.5%Mn cast and cold-rolled plate alloys, an enriched layer derived from Mn solid solution was formed at an electrorefining potential of 0.2 V; this was attributed to preferential dissolution of Al in the matrix phase, followed by Mn accumulation at the Al surface. Furthermore, dissolution of the Al-Mn-Fe and Al-Mn intermetallic compounds occurred at 0.6 and 1.0 V, respectively; thus, the dissolution behavior of Mn in the Al-Mn alloys differed between the Mn solid solution in the matrix phase and the Mn-containing intermetallic compounds. These results indicate that by controlling the microstructure of the Al-Mn alloy and the applied anodic potential, the dissolution of Mn into the 1-ethyl-3-methyl-imidazolium chloride-AlCl 3 electrolyte can be suppressed, thus preventing its co-deposition with Al on the cathode. This development is therefore anticipated to inform the development of electrorefining processes to obtain high-quality recycled Al for numerous manufacturing applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Na[sup+]/H[sup+] antiporters influence proton or sodium motive force across the membrane. Synechocystis sp. PCC 6803 has six genes encoding Na[sup+]/H[sup+] antiporters, nhaS1-5 and s110556. In this study, the function of NhaS3 was examined. NhaS3 was essential for growth of Synechocystis, and loss of nhaS3 was not complemented by expression of the Escherichia coli Na[sup+]/H[sup+] antiporter NhaA. Membrane fractionation followed by immunoblotting as well as immunogold labeling revealed that NhaS3 was localized in the thylakoid membrane of Synechocystis. NhaS3 was shown to be functional over a pH range from pH 6.5 to 9.0 when expressed in F. coli. A reduction in the copy number of nhaS3 in the Synechocystis genome rendered the cells more sensitive to high Na[sup+] concentrations. NhaS3 had no K[sup+]/H[sup+] exchange activity itself but enhanced ICuptake from the medium when expressed in an F. coli potassium uptake mutant. Expression of nhaS3 increased after shifting from low CO[sub2] to high CO[sub2] conditions. Expression of nhaS3 was also found to be controlled by the circadian rhythm. Gene expression peaked at the beginning of subjective night. This coincided with the time of the lowest rate of CO[sub2] consumption caused by the ceasing of O[sub2]-evolving photosynthesis. This is the first report of a Na[sup+]/H[sup+] antiporter localized in thylakoid membrane. Our results suggested a role of NhaS3 in the maintenance of ion homeostasis of H[sup+], Na[sup+] and K[sup+] in supporting the conversion of photosynthetic products and in the supply of energy in the dark. [ABSTRACT FROM AUTHOR]