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In recent years, heavy metals and organic pollutants have become two major obstacles to maintaining the ecological environment. Thus, choosing efficient and environmentally friendly methods and materials to remediate heavy metals and organic pollution has become a hot research topic. Porous metal–organic frameworks (MOFs) and their composites or derivatives can be used as ideal adsorbents and catalytic materials because of their unique structures and functions. This work reviews the research progress on MOF-based materials in the remediation of the water environment in the past decade. The MOF-based materials discussed here mainly include MOF composites obtained by fabrication and MOF derivatives obtained by pyrolysis. Both MOF composites and MOF derivatives are optimized materials that exhibit adsorption or catalytic performance superior to the pristine MOFs. Additionally, the interactions and mechanisms between the MOF-based materials and different heavy metals or organic pollutants are discussed in detail. Finally, some problems or defects of the MOF-based materials are also proposed considering the materials’ economic efficiency, stability and safety. There is still a long way forward for the real application of MOF-based materials. Further efforts are also needed to explore and expand the environmental remediation scope of MOF-based materials.

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Background: Gestational diabetes mellitus (GDM) is a condition of glucose intolerance and insulin resistance only diagnosed during pregnancy. GDM has exhibited several adverse effects on both mother and offspring. The current research focuses on discovering visnagin’s beneficial properties against the streptozotocin (STZ)-induced GDM in rats via alleviating the inflammation and oxidative stress. Materials and Methods: GDM was caused in the pregnant rats by the administration of 25 mg/kg of STZ by the intraperitoneal route and then treated with 20 mg/kg of visnagin for 20 consecutive days. The rats’ body weight was measured, and fasting blood glucose (FBG) status was determined using a standard glucometer. The contents of total cholesterol (TCh), triglycerides (TG), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) were assessed using kits. The MDA level, total antioxidant capacity (TAC) status, and activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione S-transferase (GST) were determined using assay kits. Kits also assessed the contents of TNF-α and IL-1β. The contents of TNF-α and IL-1β effectively improved the body weight and decreased the FBG status in the GDM rats. The visnagin also decreased the TCh, TG, and LDL, and elevated the HDL content. The content of MDA was decreased and the visnagin treatment increased SOD, CAT, GST, and GPx, and the visnagin treatment increased SOD, CAT, GST, and GPx activities SOD, CAT, GST, and GPx activities. The visnagin effectively decreased the STZ-induced histopathological alterations in the pancreas. Conclusion: Altogether, our investigation results suggest a beneficial role visnagin against STZ-induced GDM in rats via inhibiting the inflammatory responses. Hence, it can be a talented therapeutic candidate for the successful management of GDM.

Nitric acid (HNO3) modified biochar (NBC) has been demonstrated to be a promising sorbent. However, the roles of their redox-active moieties (RAMs, i.e., environmentally persistent free radicals (EPFRs) and oxygen-containing function groups) in Cr(VI) removal under varying pH and O2 conditions remain poorly understood. In this study, HNO3 oxidation caused an obvious increase in specific surface area, porous volume, RAMs content, and surface potential of the biochar, leading to the more effective removal of Cr(VI) (with the removal rate reached 100% at pH 2.0) than that of the untreated biochar. Kinetics experiments revealed that O2 and pH are of great importance for the reduction efficiency and rate of Cr(VI). RAMs on NBC can either directly reduce Cr(VI)(predominant pathway) or activate O2 to produce •O2− for indirect Cr(VI) reduction. In addition, we examined the changes in the compositions of RAMs during the reaction by tuning the RAMs compositions using methanol and hydrogen peroxide. The results of electron paramagnetic resonance and X-ray photoelectron spectroscopy analysis demonstrated that the main electron donors on NBC were different at different pH values: oxygen-containing groups, e.g., –OH and C–O–C, played a dominant role in reducing Cr(VI) under acidic conditions while the neutral condition was beneficial to EPFRs-dominated reduction. This study investigated the roles of the EPFRs and oxygen-containing function groups on HNO3 modified biochar, which may provide new insights into the promoted reduction of Cr(VI) by applications of biochar.

The ionic liquids (ILs) and their aqueous solutions have been considered as a new generation of absorption working substances for applications in gas separation and absorption refrigeration processes. It is important to understand the physicochemical properties of ionic liquids in aqueous solutions, such as chemical potential and acid-base properties before any industry application. In this study, we focused on the acid-base properties of the IL aqueous solutions by testing the pH values of the aqueous solutions of two ionic liquids, 1-ethyl-3-methylimidazolium acetate ([EMIM]Ac) and 1-hexyl-3-methylimidazolium chloride ([HMIM]Cl). All the tests were carried out at 25 and in a well controlled dry air ℃ surrounding. There were 16 water mass fractions for each of [EMIM]Ac and [HMIM]Cl aqueous solutions tested in range of 0.04 to 0.95 and 0.01 to 0.96, respectively. There, two methods, the sophisticated pH paper and the pH meter, were applied for the tests and the differences between the two test methods were detected. The test data from the two test methods and their differences were then evaluated with an aggregation film model and the activity theory for the film and aqueous solution phases. The results show that the difference of the pH values tested by the two methods is significant. The pH data from the sophisticated pH paper test present the bulk acid-base property of the IL aqueous solutions, while the pH meter can only reflect the hydrogen ion concentration in the IL aggregation film which was formed on the surface of the electrode of the pH meter. With analysis of acid-base reaction in the IL aqueous solution, a calculation model for the pH value of the bulk solution region was developed, and the data of the sophisticated pH paper test were correlated and the solution acid-base values were obtained. Based on analysis of the water species equilibrium in the IL aggregation film and the bulk aqueous solution phases and its effect on the concentration of hydrogen ions in the aggregation film, a method for calculation of the difference of pH values between the aggregation film and the bulk solution was proposed and the data from the pH meter were then fitted with the proposed calculation method. The results provide experimental data and a quantitative method for analysis of the acid-base property of IL aqueous solution systems.

Design basis earthquake may cause various internal hazards in nuclear power plants, such as fire, explosion, flooding, missiles, high-energy pipelines break, etc. In addition, earthquakes may also cause non-seismic items to fall or collapse, thus affecting safety-related systems or equipment. As the subsequent situation induced by earthquake is quite complex, no practicable methods have been presented yet to be used for the safety evaluation after earthquake. This paper introduces a feasible safety assessment concept for the above-mentioned hazards caused by the design basis earthquake based on the engineering practice experience. This general assessment concept based on the deterministic approach could be used for guidance of safety evaluation during or after earthquake for nuclear power plants.