High-speed and efficient removal of uranium (VI) from aqueous solution by hydroxyapatite-modified ordered mesoporous carbon (CMK-3)

In recent years, the synthesis and application of green, cost-effective, and sustainable materials for uranium (VI) removal was significant to environmental protection. The ordered mesoporous carbon (CMK-3) supported different mass of hydroxyapatite materials (HAP@CMK-3) were facilely synthesized via hydrothermal method. The resultant materials were characterized by XRD, FT-IR, BET, SEM, TEM mapping, and XPS, and implemented for immobilizing U(VI). Not only the specific surface area of HAP (7.01 m²/g) was increased by the loading on CMK-3 (818.37 m²/g), but also the adsorption capacity of CMK-3 was increased by HAP modification. Impressively, HAP@CMK-3 exhibited highly adsorption capacity of U(VI) with the increase of HAP deposition and was capable of achieving fast reaction. Therein to, the specific surface area of HAP@CMK-3(2:1) was 253.68 m²/g, as well as the adsorption capacity was up to 1072 mg/g (fitted by Langmuir isotherm, at pH=3.0, 298 K) and the adsorption process was completed in 30 min (followed by pseudo-second-order kinetic). The adsorption mechanisms of U(VI) on HAP@CMK-3 involved electrostatic forces, ionic interactions, and chemical complexation. This work offered new avenues to address the limitations of cost and less secondary pollution for the removal of U(IV) from wastewater.

3D ordered mesoporous TiO2@CMK-3 nanostructure for sodium-ion batteries with long-term and high-rate performance

Sodium ion battery is abundant in resources and costs low, making it very competitive in the large-scale energy storage devices. The anatase TiO₂ electrode material with insertion/extraction mechanism shows stable cycling performance, which is more in line with the technical requirements of large-scale energy storage batteries. To improve the electrical conductivity and stability of the TiO₂ electrode materials, we have synthesized anatase TiO₂ and CMK-3 composite. TiO₂ nanoparticles were deposited on the surface of CMK-3 by hydrothermal reaction, and the anode material of the SIBs with 3D network structure was prepared. With the CMK-3, the structure stability, conductivity and reaction kinetics of TiO₂@CMK-3 composite is improved. The electrochemical behavior is dominated by pseudocapacitance, which gives the material excellent high-rate performance. It delivers a reversible specific capacity of 186.3 mA h g^-1 after 100 cycles at the current density of 50 mA g^-1, 124.5 mA h g^-1 after 500 long-term cycles, meanwhile it shows an outstanding rate performance, a reversible specific capacity of 105.9 mA h g^-1 at 1600 mA g^-1, 177.3 mA h g^-1 when the current density drops to 50 mA g^-1.

A review of recent progress in molybdenum disulfide-based supercapacitors and batteries

This article reviews the recent progress in molybdenum disulfide-based supercapacitors and batteries.