Nanoconfined materials developed for efficient fluoride removal from water
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(A) NANOCONFINED STRUCTURE AND FLUORIDE REMOVAL PERFORMANCE OF LA-MG LDH/TI3C2TX.
view moreCREDIT: HE JUNYONG
Recently, the research team led by Prof. KONG Lingtao at Institute of Solid State Physics, the Hefei Institutes of Physical Science of the Chinese Academy of Sciences developed an innovative material for the efficient removal of fluoride ions from water. This newly developed material, a La-Mg LDH/Ti3C2TX adsorption membrane, leverages the nano confinement effect to enhance its performance.
The results are published in Chemical Engineering Journal.
Fluoride is a major water pollutant, with high doses causing health risks. Layered double hydroxides (LDH) are effective for removing fluoride due to their many active sites. However, the typical nanosheet structure makes it prone to material aggregation during preparation, impacting the exposure of active sites and resulting in a significant decrease in adsorption capacity. Therefore, it's important to design LDH materials that fully expose their active sites to efficiently remove fluoride ions.
In this study, researchers developed a new material called La-Mg LDH/Ti3C2TX to remove fluoride ions from water. They designed this material by combining La-Mg LDH with Ti3C2TX, which helps prevent the La-Mg LDH sheets from clumping together. This combination increases the surface area and active sites of the material, making it more effective at capturing fluoride ions.
The La-Mg LDH/Ti3C2TX material can absorb fluoride per gram, and other common ions in the water. Even after being used and regenerated five times, the material still removes over 80% of the fluoride ions from water. Additionally, the levels of magnesium, titanium, and lanthanum in the filtered water remain below national safety standards, showing that the material is stable and safe.
Computer simulations confirmed that fluoride ions are more easily trapped at the interface between La-Mg LDH and Ti3C2TX rather than just on the surface. The material has a high water flow rate, indicating it has great potential for practical use in water treatment.
This research presents a new solution to improve the adsorption capacity of materials used for fluoride removal by addressing the issue of material aggregation.
"Our study could lead to more effective methods for purifying water," said Dr. HE Junyong, a member of the team.
Nanoconfined Materials Developed for Efficient Fluoride Removal from Water
The fluoride removal mechanism of La-Mg LDH/Ti3C2TX adsorption membrane material.
CREDIT
HE Junyong
JOURNAL
Chemical Engineering Journal
ARTICLE TITLE
Nanoconfinement regulation of La-Mg LDH/Ti3C2TX (T = O, OH) for effective removal of fluoride: Membrane fabrication and mechanism revelation
Novel two-step electrolysis of water suggested for hydrogen production
HEFEI INSTITUTES OF PHYSICAL SCIENCE, CHINESE ACADEMY OF SCIENCES
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PLASMA ASSISTED PREPARATION OF HIGH-CAPACITY BIPOLAR ELECTRODES FOR HYDROGEN PRODUCTION BY TWO-STEP WATER ELECTROLYSIS.
view moreCREDIT: CHEN CHANGLUN
Recently, a research group led by Prof. CHEN Changlun from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences, along with Institute of Energy, Hefei Comprehensive National Science Center, developed advanced cobalt-doped nickel hydroxide bipolar electrodes and non-noble metal catalysts, significantly improving the efficiency and stability of two-step water electrolysis for hydrogen production.
The related results were published in Chemical Engineering Journal and Journal of Colloid and Interface Science.
Traditional alkaline electrolyzers face issues like mismatching with fluctuating renewable energies and hydrogen/oxygen mixing under high pressure, limiting their applications. Two-step water electrolysis addresses these problems by completely separating hydrogen and oxygen production in time and space using a bipolar electrode, eliminating the need for a costly membrane separator. The key is developing high-performance bipolar electrode materials and efficient cell designs. However, commonly used nickel hydroxide electrodes have limitations in electric buffering capacity and charging-discharging stability.
In this study, the team used a one-step electrodeposition method to create cobalt-doped flexible nickel hydroxide bipolar electrodes on carbon cloth. Cobalt doping improved conductivity, electronic cache performance, and prevented parasitic oxygen production during hydrogen production.
They also developed non-noble metal catalysts, including molybdenum-doped nickel cobalt phosphide and plasma-induced iron composite cobalt oxide bifunctional electrodes, which showed high durability and activity. These electrodes enabled hydrogen and oxygen production at different times and places by switching the current direction, resulting in low cell voltages, high decoupling efficiency, and high energy conversion efficiency.
To enhance layered double hydroxide (LDH) electrodes, which suffer from limited capacity and poor conductivity/stability, the team used nonthermal plasma technology to prepare nitrogen-doped nickel-cobalt LDH and nitrogen-doped reduced graphene oxide/nickel-cobalt LDH electrodes, significantly improving capacitance and conductivity.
Two-step water electrolysis is promising for large-scale hydrogen storage and applications like 5G base stations and data centers. "Our performance indicators for two-step water electrolysis for hydrogen production are synchronized with advanced indicators globally, marking an important step towards industrial operation," said Prof. CHEN Changlun.
JOURNAL
Journal of Colloid and Interface Science
ARTICLE TITLE
High buffering capacity cobalt-doped nickel hydroxide electrode as redox mediator for flexible hydrogen evolution by two-step water electrolysis
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