MOF-derived MnO@C with high activity for electric field-assisted catalytic oxidation of aqueous pollutants

Cobalt regulation biocathode with sulfate-reducing bacteria for enhancing the reduction of antimony and the removal of sulfate in a microbial electrolysis cell simultaneously

Antimony (Sb) contamination in water resources poses a critical environmental and health challenge globally. Sulfate reducing bacteria (SRB) are employed to reduce SO42- to S2- for removing Sb in a microbial electrolysis cell (MEC). Yet, the reduction efficiency of reducing SO42- and Sb(V) through SRB remains relatively low, and the underlying mechanism remains elusive. Herein, the MEC reactor modified with Co-based or Fe-based MOF materials was served to enhance the electron transfer between the aqueous environment and the microorganisms to enhance the operational efficiency of the bio-electrochemical system (MEC-SRB). This study highlights the central role of removal efficiency as a critical performance metric and its direct correlation with material properties and mechanisms. The results demonstrate that the ZIF-8@Co electrode significantly outperformed other materials, achieving 98.7% sulfate and 93.1% total Sb removal over multiple cycles. Electrochemical analysis revealed that the superior performance of ZIF-8@Co electrode is attributed to rapid electron transfer and low electronic impedance. The charge transfer resistance of the ZIF-8@Co group was 155 Ω, significantly lower than that of the ZIF-8@Fe group (1724 Ω) and the ZIF-8@CoFe group (427 Ω). These findings demonstrate that the material's ability to facilitate electron transfer directly governs the pollutant removal efficiency. Fluorescence analysis revealed that the ZIF-8@Co electrode supported a denser biofilm and enhanced microbial activity. Mechanistic studies confirmed that Sb(V) was reduced and deposited as Sb2S3 precipitate, which was further characterized and analyzed by methods such as XRD and XPS. This research elucidates the potential and underlying mechanisms of an electrically stimulated SRB bio-electrochemical system for effective Sb-containing wastewater treatment. Our findings provide crucial insights for developing high-efficiency, sustainable remediation technologies for heavy metal contamination, with significant potential for real-world application in water treatment and environmental protection.

ZnCo Bimetallic Macro-Microporous Metal-Organic Frameworks for Efficient Adsorption of Dyes

The significant threat posed by dye wastewater has driven the development of efficient adsorbents, such as metal organic frameworks (MOFs). Specifically, we explore the synthesis and application of ZnCo-based bimetallic zeolite imidazolate frameworks with a macro-microporous structure (SOM-ZnCo-ZIF), which exhibit enhanced adsorption capacity for dyes due to their large specific surface area and ordered porous arrangement. When SOM-ZnCo-ZIF is immersed in DMA solutions of methylene blue, methyl orange, crystal violet, and rhodamine B, due to its high specific surface area and the synergistic effect of ZnCo bimetallic clusters, SOM-ZnCo-ZIF significantly enhances dye adsorption. Notably, its adsorption capacity for Rhodamine B reaches an impressive 6798.9 mg/g, and within just 1 min, 0.5 g/L of SOM-ZnCo-ZIF can remove over 97% of Rhodamine B from a 60 mg/L solution. Moreover, it maintained a 92.8% dye removal efficiency in ten cycles without regeneration, demonstrating the effective adsorption capacity of SOM-ZnCo-ZIF. Density functional theory calculations have shown that the adsorption energy of ZnCo bimetallic ZIF for Rhodamine B is approximately twice that of a single metal. SOM-ZnCo-ZIF exhibits strong adsorption of Rhodamine B mainly due to its macro-microporous structure, which provides larger pore sizes (∼250 nm) allowing the dye molecules to infiltrate the porous network, and its ability to facilitate π-π stacking interactions between the benzene rings of Rhodamine B and the imidazole rings of the ZIF. Additionally, the interaction is further enhanced by strong coordination bonds and electrostatic interactions between the cationic dye and the negatively charged framework. This work not only proposes an effective adsorbent to remove Rhodamine B but also provides valuable insights for the rational design and synthesis of environmentally sustainable MOF structures.

Unveiling the scope and perspectives of MOF-derived materials for cutting-edge applications

Although synthesis and design of MOFs are crucial factors to the successful implementation of targeted applications, there is still lack of knowledge among researchers about the synthesis of MOFs and their derived composites for practical applications. For example, many researchers manipulate study results, and it has become quite difficult to quit this habit specifically among the young researchers Undoubtedly, MOFs have become an excellent class of compounds but there are many challenges associated with their improvement to attain diverse applications. It has been noted that MOF-derived materials have gained considerable interest owing to their unique chemical properties. These compounds have exhibited excellent potential in various sectors such as energy, catalysis, sensing and environmental applications. It is worth mentioning that most of the researchers rely on commercially available MOFs for use as precursor supports, but it is an unethical and wrong practice because it prevents the exploration of the hidden diversity of similar materials. The reported studies have significant gaps and flaws, they do not have enough details about the exact parameters used for the synthesis of MOFs and their derived materials. For example, many young researchers claim that MOF-based materials cannot be synthesized as per the reported instructions for large-scale implementation. In this regard, current article provides a comprehensive review of the most recent advancements in the design of MOF-derived materials. The methodologies and applications have been evaluated together with their advantages and drawbacks. Additionally, this review suggests important precautions and solutions to overcome the drawbacks associated with their preparation. Applications of MOF-derived materials in the fields of energy, catalysis, sensing and environment have been discussed. No doubt, these materials have become excellent class but there are still many challenges ahead to specify it for the targeted applications.