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Capacitive deionization is an emerging desalination technology with mild operation conditions and high energy efficiency. However, its application is limited due to the low deionization capacity of traditional capacitive electrodes. Herein, we report a novel dual-ion capacitive deionization system with a lithium-ion battery cathode LiMn2O4/C and a sodium-ion battery anode NaTi2(PO4)3/C. Lithium ions could enhance the charge transfer during CDI desalination, while NaTi2(PO4)3/C provided direct intercalation sites for sodium ions. The electrochemical capacities of the battery electrodes fitted well, which was favorable for the optimization of the desalination capacity. The low potential of the redox couple Ti3+/Ti4+ (−0.8 V versus Ag/AgCl) and intercalation/deintercalation behaviors of sodium ions that suppressed hydrogen evolution could enlarge the voltage window of the CDI process to 1.8 V. The novel CDI cell achieved an ultrahigh desalination capacity of 140.03 mg·g−1 at 1.8 V with an initial salinity of 20 mM, revealing a new direction for the CDI performance enhancement.

Hexavalent chromium [Cr(VI)] is a priority heavy metal pollutant causing a series of environmental issues, and bio-reduction of Cr(VI) to trivalent chromium can remarkably decrease the environmental risk of Cr(VI). The reduction and resistance abilities of microorganisms to Cr(VI) can be dramatically improved by acclimatization. In the present study, we collected Shewanella oneidensis MR-1 from a 120-day acclimatization by increasing Cr(VI) concentration in the culture media to investigate its adaptation mechanisms under long-term Cr(VI) stress at the proteome level. Tandem mass tag-based quantitative proteomic analysis was performed to study the differences between 9 collected samples. A total of 2500 proteins were quantified from 2723 identified protein groups. Bioinformatics analysis showed that the differentially expressed proteins after the 120-day Cr(VI) acclimatization were mostly related to flagellar assembly, ribosomes, transport, sulfur metabolism, and energy metabolism. The findings of this study present novel insights into the molecular mechanisms for the reduction and resistance of S. oneidensis MR-1 responding to long-term Cr(VI) stress at the proteome level. Keywords: Shewanella oneidensis MR-1, Hexavalent chromium, Long-term acclimatization, Permanent effect, Short-term stimulus