Regulation of Structure and Anion-Exchange Performance of Layered Double Hydroxide: Function of the Metal Cation Composition of a Brucite-like Layer

Immobilisation of iodide in alkali-activated materials

At the Fukushima Daiichi Nuclear Power Station (FDNPS), continuous water circulation cools fuel debris, leading to the presence of radionuclides such as Sr-30, Cs-137, and I-129 in the cooling water. These radionuclides are adsorbed and co-precipitated by various materials. Among them, I-129 is a key radionuclide for safety assessment during the final disposal of adsorbent and co-precipitation materials, owing to its long half-life and poor sorption. Alkali-activated materials (AAM) have been demonstrated to immobilise cationic radionuclides but not anionic radionuclides. Here, layered double hydroxide (LDH), magnesium oxide (MgO), and silver nitrate (AgNO3) were investigated as additive materials to immobilise I- in potassium-based AAM (K-AAM). Our findings revealed that LDH and MgO were not effective in retaining I- in K-AAM. In the case of LDH addition, the high anion exchange capacity of LDH was rendered ineffective, as its adsorption sites were occupied by highly selective silicate anions. In the case of MgO addition, magnesium silicate hydrates (M-S-H) were formed, which did not appear to possess the ability to retain I-, despite the desirable in situ synthesis of LDH containing alumina in K-AAM. Conversely, the addition of AgNO3 to K-AAM resulted in a reduced leaching rate, which was attributed to AgI formation. The immobilisation could be enhanced by adjusting the amount of AgNO3 incorporated into the K-AAM during the fabrication process. In conclusion, the leaching of I- from spent adsorbent and co-precipitation materials embedded in the K-AAM matrix could be suppressed when AgI was sufficiently generated within the K-AAM matrix.

Recent advances in CO2 capture and mineralization using layered double hydroxide-based materials: A review

The continuous release of substantial amounts of carbon dioxide (CO2) to the atmosphere has resulted in numerous severe adverse effects. Several materials have been synthesized and utilized for CO2 capture. One class of such materials is layered double hydroxides (LDHs), which have emerged as promising materials for CO2 capture due to their tunable properties, high surface area, and excellent CO2 adsorption capabilities. Although there are some review articles on CO2 capture and conversion using various materials, there is still a notable lack of thorough reviews focusing on the utilization of LDH-based materials for CO2 capture. Additionally, the field of CO2 capture and mineralization using LDH-based materials is rapidly evolving, necessitating up-to-date comprehensive reviews to analyze, evaluate, and condense the dispersed information found in recently published research articles. Accordingly, this review article provides a comprehensive overview of recent advancements in CO2 capture using LDH-based materials. After briefly introducing the topic, different synthesis protocols of LDH-based materials are briefly reviewed. Then, CO2 capture using LDHs, calcined LDHs, impregnated LDHs, composites containing LDHs, amine functionalized LDHs, and during steam methane reforming, are thoroughly analyzed and discussed. Additionally, the effects of synthesis method and post treatment of LDH-based materials on CO2 capture, effect of modification and functionalization on LDHs, and the effects of various process conditions including temperature, pressure, water vapor, and gas composition on the performance of CO2 capture by LDH-based materials are reviewed. Limitations, challenges, obstacles, and remaining knowledge gaps are highlighted, and future research works to address them are proposed.

Ti3C2 (MXene), an advanced carrier system: role in photothermal, photoacoustic, enhanced drugs delivery and biological activity in cancer therapy

In the realm of healthcare and the advancing field of medical sciences, the development of efficient drug delivery systems become an immense promise to cure several diseases. Despite considerable advancements in drug delivery systems, numerous challenges persist, necessitating further enhancements to optimize patient outcomes. Smart nano-carriers, for instance, 2D sheets nano-carriers are the recently emerging nanosheets that may garner attention for targeted delivery of bioactive compounds, drugs, and genes to kill cancer cells. Within these advancements, Ti3C2TX-MXene, characterized as a two-dimensional transition metal carbide, has surfaced as a prominent intelligent nanocarrier within nanomedicine. Its noteworthy characteristics facilitated it as an ideal nanocarrier for cancer therapy. In recent advancements in drug delivery research, Ti3C2TX-MXene 2D nanocarriers have been designed to release drugs in response to specific stimuli, guided by distinct physicochemical  parameters. This review emphasized the multifaceted role of Ti3C2TX-MXene as a potential carrier for delivering poorly hydrophilic drugs to cancer cells, facilitated by various polymer coatings. Furthermore, beyond drug delivery, this smart nanocarrier demonstrates utility in photoacoustic imaging and photothermal therapy, further highlighting its significant role in cellular mechanisms.

Advances of Layered Double Hydroxide-Based Materials for Tumor Imaging and Therapy

Layered double hydroxides (LDH) are a class of functional anionic clays that typically consist of orthorhombic arrays of metal hydroxides with anions sandwiched between the layers. Due to their unique properties, including high chemical stability, good biocompatibility, controlled drug loading, and enhanced drug bioavailability, LDHs have many potential applications in the medical field. Especially in the fields of bioimaging and tumor therapy. This paper reviews the research progress of LDHs and their nanocomposites in the field of tumor imaging and therapy. First, the structure and advantages of LDH are discussed. Then, several commonly used methods for the preparation of LDH are presented, including co-precipitation, hydrothermal and ion exchange methods. Subsequently, recent advances in layered hydroxides and their nanocomposites for cancer imaging and therapy are highlighted. Finally, based on current research, we summaries the prospects and challenges of layered hydroxides and nanocomposites for cancer diagnosis and therapy.