ZIF-8/Graphene Oxide Hybrid Membranes as Breathable and Protective Barriers against Chemical Warfare Agents

Personal protective equipment against chemical warfare agents and other toxic chemicals must be protective, be breathable, and have a low thermal burden. Selectively permeable membranes are promising candidates for such equipment. In this study, a hybrid membrane consisting of a continuous and thin zeolitic imidazolate framework (ZIF)-8 layer on an oxygen-rich small-flake graphene oxide layer was produced using a simple and scalable synthesis method. The small intrinsic pores of ZIF-8 allow it to selectively separate chemicals via size exclusion while permitting water vapor to permeate out. The ZIF-8/graphene oxide membrane had high selectivity for the penetration of water vapor over nerve agent simulants (ratio of dimethyl methylphosphonate to water vapor transmittance rates of ∼312) with a high water vapor transmittance rate of 3000 g m-2 day-1. This protective barrier layer is a promising material for next-generation protective clothing with enhanced comfort and operability.

Functional MOF-Based Materials for Environmental and Biomedical Applications: A Critical Review

Over the last ten years, there has been a growing interest in metal-organic frameworks (MOFs), which are a unique category of porous materials that combine organic and inorganic components. MOFs have garnered significant attention due to their highly favorable characteristics, such as environmentally friendly nature, enhanced surface area and pore volume, hierarchical arrangements, and adjustable properties, as well as their versatile applications in fields such as chemical engineering, materials science, and the environmental and biomedical sectors. This article centers on examining the advancements in using MOFs for environmental remediation purposes. Additionally, it discusses the latest developments in employing MOFs as potential tools for disease diagnosis and drug delivery across various ailments, including cancer, diabetes, neurological disorders, and ocular diseases. Firstly, a concise overview of MOF evolution and the synthetic techniques employed for creating MOFs are provided, presenting their advantages and limitations. Subsequently, the challenges, potential avenues, and perspectives for future advancements in the utilization of MOFs in the respective application domains are addressed. Lastly, a comprehensive comparison of the materials presently employed in these applications is conducted.

Recent advances in the application of water-stable metal-organic frameworks: Adsorption and photocatalytic reduction of heavy metal in water

Heavy metals pollution in water is a global environmental issue, which has threatened the human health and environment. Thus, it is important to remove them under practical water environment. In recent years, metal-organic frameworks (MOFs) with water-stable properties have attracted wide interest with regard to the capture of hazardous heavy metal ions in water. In this review, the synthesis strategy and postsynthesis modification preparation methods are first summarized for water-stable MOFs (WMOFs), and then the recent advances on the adsorption and photocatalytic reduction of heavy metal ions in water by WMOFs are reviewed. In contrast to the conventional adsorption materials, WMOFs not only have excellent adsorption properties, but also lead to photocatalytic reduction of heavy metal ions. WMOFs have coupling and synergistic effects on the adsorption and photocatalysis of heavy metal ions in water, which make it more effective in treating single pollutants or different pollutants. In addition, by introducing appropriate functional groups into MOFs or synthesizing MOF-based composites, the stability and ability to remove heavy metal ions of MOFs can be effectively enhanced. Although WMOFs and WMOF-based composites have made great progress in removing heavy metal ions from water, they still face many problems and challenges, and their application potential needs to be further improved in future research. Finally, this review aims at promoting the development and practical application of heavy metal ions removal in water by WMOFs.

Simultaneously removal of Cr(VI) and Cd(II) from water using a flower-like primary battery nanosystem

In this study, a new flower-like primary battery nanosystem termed "Zn/CCP/ZIF-8" was prepared by depositing conductive carbon paint (CCP) and zeolitic imidazolate framework-8 (ZIF-8) on a zinc plate (Zn). Therein, CCP had good conductivity performance and adhesiveness, ZIF-8 and Zn/CCP/ZIF-8 possessed BET specific surface areas of 1909.5 and 1265.4 m²/g respectively. The results showed that the Zn/CCP/ZIF-8 nanosystem could effectively simultaneously adsorb hexavalent chromium (Cr(VI)) and bivalent cadmium (Cd(II)) from water. The system could promote the transfer of electrons from Zn to Cr(VI) and Cd(II) which were effectively reduced to trivalent chromium (Cr(III)) and cadmium (Cd), respectively. The resultant Zn/CCP/ZIF-8/Cr/Cd composite was then easily separated from water. The adsorption isotherm, kinetics, and thermodynamics of the prepared Zn/CCP/ZIF-8 for Cr(VI) and Cd(II) were investigated. An electrochemistry performance test proved that the Zn/CCP/ZIF-8 system was a primary battery. Notably, the Zn/CCP/ZIF-8 system substantially reduced the amounts of Cr(VI) and Cd(II) absorbed by zebrafish and water spinach, thus increasing food safety. The results of a rat test indicated that the Zn/CCP/ZIF-8 system possessed a high biosafety. This study provides a promising, eco-friendly, and facile method for the simultaneously treatment of Cr(VI) and Cd(II) contamination of water.

Polydimethylsiloxane/ZIF-8@GO sponge headspace solid-phase extraction followed by GC-MS for the analysis of lavender essential oil

A novel microwave-assisted (MA) headspace solid-phase extraction (HS-SPE) based on polydimethylsiloxane (PDMS)/ZIF-8@GO sponge was developed for the simultaneous extraction and determination of essential oil constituents in lavender. The PDMS/ZIF-8@GO sponge with a high surface area and excellent adsorption capacity was successfully applied in the HS-SPE process. Microwave-assisted coupled with PDMS/ZIF-8@GO sponge headspace solid-phase extraction followed by GC-MS was proposed. Different experimental parameters were investigated. The optimal conditions were found to be as follows: 2:1 as the quality ratio of ZIF-8 to GO, ZIF-8@GO dosage of 30 mg, microwave power of 600 W, extraction time of 10 min and desorption solvent of n-hexane. This method was successfully applied to the analysis of 11 samples of lavender in different varieties. A total of 52 compounds were identified by the proposed method. A good linearity was observed from 14 to 800 ng with a correlation coefficient (R²) value of >0.99. Multivariate statistical analysis was used to establish the relationship between the varieties and the volatile components for further discriminant analysis. These results demonstrated that the MA-PDMS/ZIF-8@GO is an efficient, sensitive and small sample consumption method for the determination of the essential oil in dried plant materials.

Core–shell structured nanoporous N-doped carbon decorated with embedded Co nanoparticles as bifunctional oxygen electrocatalysts for rechargeable Zn–air batteries

Highly active core–shell structured PNC@CoNC was successfully prepared and used as an effective air–electrode catalyst in advanced Zn–air batteries.

The research trends of metal-organic frameworks in environmental science: a review based on bibliometric analysis

Metal-organic frameworks, an emerging class of porous material, have developed rapidly in recent years. In order to clarify the application of metal-organic frameworks in the field of environmental science, 1386 articles over the last 20 years were obtained from Scopus and analysed by the bibliometric method. And the collaboration between countries, institutions and authors and the co-occurrence of keywords were also conducted using VOSviewer. The results indicated that this area of research has entered a fast-developing stage. The number of articles published has grown from 7 articles in 1999 to 378 articles in 2018. The most productive country was China with 626 articles published. The most productive institution was the Chinese Academy of Sciences, and the most productive author was Jhung SH from Kyungpook National University of South Korea. Although metal-organic frameworks have been widely used in adsorption and catalytic degradation of pollutants from the environment, the removal mechanism of pollutants by MOFs, the stability improvement and the cost reduction of metal-organic frameworks are still the main challenges for their practical applications.

Lipase immobilization on UiO-66/poly(vinylidene fluoride) hybrid membranes and active catalysis in the vegetable oil hydrolysis

This is the first report in which UiO-66/PVDF hybrid membranes with high immobilization efficiency for lipase were constructed.

Zwitterionic superabsorbent polymer hydrogels for efficient and selective removal of organic dyes

A novel zwitterionic superabsorbent polymer hydrogel [ZI-SAH] was synthesized by free radical polymerization and used for the removal of crystal violet (CV) and congo red (CR) from an aqueous medium.