Efficiency of aluminum-pillared montmorillonite on the removal of cesium and copper from aqueous solutions.

Global lithium-ion battery deployments stand poised to grow substantially in the coming years, but it will be necessary to include sustainability considerations in the design of electrode materials. The current cathode chemistry relies heavily on cobalt, which, due to its scarcity and the environmental abuse and violation of human rights during its mining, must be replaced by abundant and environmentally friendly elements such as redox-active manganese. LiMnO2 is a strong contender for sustainable cathodes but cycles poorly because the Jahn–Teller distorted Mn3+ ions destabilize the lattice framework. Here, we report a LiMnO2 cathode design with interwoven spinel and layered domains. At the interface between these two domains, the Mn dz2 orbitals are oriented perpendicular to each other, giving rise to interfacial orbital ordering, which suppresses the otherwise cooperative Jahn–Teller distortion and Mn dissolution. As a result, the heterostructured cathode delivers enhanced structural and electrochemical cycling stability. This work provides a new strategy for interface engineering, possibly stimulating more research on Mn-rich cathode materials for sustainable lithium-ion batteries. The field of battery chemistry must embrace abundant elements such as Mn for improved sustainability. Here the authors engineer the orientation of Mn 3d orbitals, resulting in excellent performance in LiMnO2 cathodes.

LiMnO2 cathode stabilized by interfacial orbital ordering for sustainable lithium-ion batteries

The sorption behaviour of synthetic sodium nonatitanate and zeolite A for removing radioactive strontium from aqueous wastes

The surface enthalpies of manganese oxide phases, hausmannite (Mn3O4), bixbyite (Mn2O3), and pyrolusite (MnO2), were determined using high-temperature oxide melt solution calorimetry in conjunction with water adsorption calorimetry. The energy for the hydrous surface of Mn3O4 is 0.96 ± 0.08 J/m2, of Mn2O3 is 1.29 ± 0.10 J/m2, and of MnO2 is 1.64 ± 0.10 J/m2. The energy for the anhydrous surface of Mn3O4 is 1.62 ± 0.08 J/m2, of Mn2O3 is 1.77 ± 0.10 J/m2, and of MnO2 is 2.05 ± 0.10 J/m2. Supporting preliminary findings (Navrotsky et al. 2010), the spinel phase (hausmannite) has a lower surface energy than bixbyite, whereas the latter has a smaller surface energy than pyrolusite. Oxidation-reduction phase equilibria at the nanoscale are shifted to favor the phases of lower surface energy—Mn3O4 relative to Mn2O3 and Mn2O3 relative to MnO2. We also report rapidly reversible structural and phase changes associated with water adsorption/desorption for the nanophase manganese oxide assemblages.

/pdf/thermodynamics-of-manganese-oxides-effects-of-particle-size-3h8htxc594.pdf

Thermodynamics of manganese oxides: Effects of particle size and hydration on oxidation-reduction equilibria among hausmannite, bixbyite, and pyrolusite

Preparation of zirconium-manganese oxide/polyacrylonitrile (Zr-Mn oxide/PAN) composite spheres and the investigation of Sr(II) sorption by experimental design

Oxidation of synthetic hausmannite (Mn3O4) to manganite (MnOOH)

Hydrous, amorphous MnO2–TiO2 composites demonstrating high affinity towards strontium and uranium at pH = 7 are obtained by means of template synthesis. The best distribution coefficients, as found using model solutions (K
 d
 Sr = 55000 mL/g and K
 d
 U
 = 40000 mL/g) and Chernobyl shelter water (K
 d
 Sr = 3800 mL/g), are gained for the samples containing equimolar amounts of manganese dioxide and titania precipitated using K+ as template cation.

Amorphous MnO2 –TiO2 Composites as Sorbents for Sr2+ and UO22+

Hydrous, amorphous manganese oxide/titanium oxide composites (AMTO) obtained via template synthesis using alkali metal ions as templates have been characterized. Their applicability in remediation technologies has been tested, specifically for 90Sr removal from Savannah River Site high-level waste supernatants (SHLW) and Chernobyl 4th Block Shelter water (CSW) simulants. Sorption isotherms were used to establish the efficiency of the templating process, while the proton-exchange capacity of AMTO was determined to show that the solids were really protonated. Use of the 90Sr isotope showed that there was little dependence of the distribution coefficients for AMTO on pH, and at pH < 7, i.e., in neutral and acidic media, AMTO had a much greater affinity for strontium than commercial sorbents. Tests with SHLW and CSW simulants revealed that AMTO is capable of removing more than 99% of 90Sr from such wastes. Hence, it could be useful for solving decontamination problems.

https://journals.sagepub.com/doi/pdf/10.1260/026361707781421979

Appraisal of Mixed Amorphous Manganese Oxide/Titanium Oxide Sorbents for the Removal of Strontium-90 from Solutions, with Special Reference to Savannah River Site and Chernobyl Radioactive Waste Simulants:

Oksana I. Pendelyuk

Papers

Oxidation of synthetic hausmannite (Mn3O4) to manganite (MnOOH)

Amorphous MnO2 –TiO2 Composites as Sorbents for Sr2+ and UO22+

Appraisal of Mixed Amorphous Manganese Oxide/Titanium Oxide Sorbents for the Removal of Strontium-90 from Solutions, with Special Reference to Savannah River Site and Chernobyl Radioactive Waste Simulants:

On the optimal design of amorphous manganese oxide for applications in power sources