Ion desorption is extremely challenging for adsorbents with superior performance, and widely used conventional desorption methods involve high acid or base concentrations and large consumption of reagents. Here, we experimentally demonstrate the rapid and efficient desorption of ions on magnetite-graphene oxide (M-GO) by adding low amounts of Al³⁺. The corresponding concentration of Al³⁺ used is reduced by at least a factor 250 compared to conventional desorption method. The desorption rate reaches ~97.0% for the typical radioactive and bivalent ions Co²⁺, Mn²⁺, and Sr²⁺ within ~1 min. We achieve effective enrichment of radioactive ⁶⁰Co and reduce the volume of concentrated ⁶⁰Co solution by approximately 10 times compared to the initial solution. The M-GO can be recycled and reused easily without compromising its adsorption efficiency and magnetic performance, based on the unique hydration anionic species of Al³⁺ under alkaline conditions. Density functional theory calculations show that the interaction of graphene with Al³⁺ is stronger than with divalent ions, and that the adsorption probability of Al³⁺ is superior than that of Co²⁺, Mn²⁺, and Sr²⁺ ions. This suggests that the proposed method could be used to enrich a wider range of ions in the fields of energy, biology, environmental technology, and materials science.

The two-dimensional (2D) “sandwich” structure composed of a cation plane located between two anion planes, such as anion-rich CrI₃, VS₂, VSe₂, and MnSe₂, possesses exotic magnetic and electronic structural properties and is expected to be a typical base for next-generation microelectronic, magnetic, and spintronic devices. However, only a few 2D anion-rich “sandwich” materials have been experimentally discovered and fabricated, as they are vastly limited by their conventional stoichiometric ratios and structural stability under ambient conditions. Here, we report a 2D anion-rich NaCl₂ crystal with sandwiched structure confined within graphene oxide membranes with positive surface potential. This 2D crystal has an unconventional stoichiometry, with Na:Cl ratio of approximately 1:2, resulting in a molybdenite-2H-like structure with cations positioned in the middle and anions in the outer layer. The 2D NaCl₂ crystals exhibit room-temperature ferromagnetism with clear hysteresis loops and transition temperature above 320 K. Theoretical calculations and X-ray magnetic circular dichroism (XMCD) spectra reveal the ferromagnetism originating from the spin polarization of electrons in the Cl elements of these crystals. Our research presents a simple and general approach to fabricating advanced 2D unconventional stoichiometric materials that exhibit half-metal and ferromagnetism for applications in electronics, magnetism, and spintronics.

Membrane methods exhibit great potential for application in radioactive liquid waste treatment. In this work, we prepared a reduced graphene oxide using the amino-hydrothermal method (AH-rGO) that exhibited effective rejection rates of 99.9% for CoCl₂, ZnCl₂, NiCl₂, and radionuclide ⁶⁰Co solutions with an ultrahigh water permeance of >71.9 L m⁻² h⁻¹ bar⁻¹. The thickness of the AH-rGO membranes affects the water permeance, as the membrane with a thickness of ≈250 nm has the highest water permeance of up to 125.1 L m⁻² h⁻¹ bar⁻¹ with the corresponding rejection rate of 86.8%. Importantly, this is the most permeable membrane with a satisfactory level of the rejection rate for typical radioactive ions of Co²⁺, Zn²⁺, and Ni²⁺. Moreover, the AH-rGO membranes presented excellent stability. These findings demonstrate the potential of reduced graphene oxide (rGO) membranes for radioactive liquid waste treatment.

Ion desorption is extensive and extremely challenging for adsorbents with superior performance, for which conventional desorption methods involving high acid or base concentrations and large consumption of reagents are widely used. Here we experimentally demonstrated the unexpectedly rapid and efficient desorption of ions on magnetite–graphene oxide (M–GO) by adding trace amounts of Al³⁺. The corresponding concentration of Al³⁺ used was reduced by a factor of at least 250 compared with the conventional desorption method. The desorption rate reached up to ~ 97.0% for the typical radioactive and bivalent ions of Co²⁺, Mn²⁺, and Sr²⁺ within ~ 1 min. Importantly, we achieved the effective enrichment of radioactive ⁶⁰Co, with the volume of the concentrated ⁶⁰Co solution reduced by approximately 10 times compared with the initial solution. Density functional theory calculations revealed that the interaction of graphene with Al³⁺ was much stronger than that with divalent ions, yielding the adsorption probability of Al³⁺ superior to Co²⁺, Mn²⁺, and Sr²⁺ ions, suggesting that the proposed method could be used to enrich a wider range of ions in the fields of energy, biology, environment, and materials science.

Thermoelectric materials composed of 2D structures have received extensive attention and research due to their potential properties. The development of novel 2D materials will provide many valuable technological characteristics for thermoelectric applications. Here, fast thermoelectric responses are reported from unconventional Na‐I stoichiometry in reduced graphene oxide films (Na‐I@rGO). The thermoelectric mechanism is based on the Seebeck effect caused by the heterogeneous structure between the rGO layers from Na ₂ I and NaI. The formation of this heterogeneous structure is attributed to the gravity‐driven ion permeation during the preparation process and cation‐π interactions. Na‐I@rGO film exhibits a significant thermoelectric current at a temperature difference (Δ T ) of 40 K (peak current ∼650 nA). The Seebeck coefficient of Na‐I@rGO film is ≈22.7 µV K ⁻¹ for a Δ T range of 2−40 K. Importantly, Na‐I@rGO film has a fast response (0.6 s) as a self‐powered sensing device, which is comparable to that of most other reported classical thermoelectric materials. The Na‐I@rGO sensor can be suitable for fast detecting transient extreme temperature variations, such as flame and liquid nitrogen. These findings can provide inspiration for the design of 2D thermoelectric structures on graphene films.