The high-throughput production of the eco-friendly MIL-88A(Fe) was achieved under mild reaction conditions with normal pressure and temperature. The as-prepared MIL-88A(Fe) exhibited efficient photo-Fenton catalytic ofloxacin (OFL) degradation upon visible light irradiation with good stability and reusability. The OFL (20.0 mg/L) was completely degraded within 50 min under visible light with the aid of MIL-88A(Fe) (0.25 g/L) and H2O2 (1.0 mL/L) in aqueous solution (pH = 7.0). The hydroxyl radicals (·OH) are the main active species during the photo-Fenton oxidation process. Meanwhile, the degradation intermediates and the corresponding degradation pathways were identified and proposed with the aid of both ultra-high performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) and density functional theory (DFT) calculations. Finally, the degradation product library was firstly established to identify intermediate transformation products (TPs) with their variation of concentration, and their corresponding toxicologic activities were assessed via Toxtree and T.E.S.T software as well. Finally, the MIL-88A is efficient and stable with four cycles’ catalysis operations, demonstrating good potential for water treatment.
Nitrate (NO3−) is a ubiquitous contaminant in water and wastewater. Conventional treatment processes such as adsorption and membrane separation suffer from low selectivity for NO3− removal, causing high energy consumption and adsorbents usage. In this study, we demonstrate selective removal of NO3− in an electrosorption process by a thin, porous carbonized eggshell membrane (CESM) derived from eggshell bio-waste. The CESM possesses an interconnected hierarchical pore structure with pore size ranging from a few nanometers to tens of micrometers. When utilized as anode in an electrosorption process, the CESM exhibited strong selectivity for NO3− over Cl−, SO42−, and H2PO4−. Adsorption of NO3− by the CESM reached 2.4 × 10−3 mmol/m2, almost two orders of magnitude higher than that by activated carbon (AC). More importantly, the CESM achieved NO3−/Cl− selectivity of 7.79 at an applied voltage of 1.2 V, the highest NO3−/Cl− selectivity value reported to date. The high selectivity led to a five-fold reduction in energy consumption for NO3− removal compared to electrosorption using conventional AC electrodes. Density function theory calculation suggests that the high NO3− selectivity of CESM is attributed to its rich nitrogen-containing functional groups, which possess higher binding energy with NO3− compared to Cl−, SO42−, and H2PO4−. These results suggest that nitrogen-rich biomaterials are good precursors for NO3− selective electrodes; similar chemistry can also be used in other materials to achieve NO3− selectivity.
This work demonstrates the successful immobilization of MIL-88A(Fe) MOF on cotton fibers to fabricate MIL-88A(Fe)/cotton fibers (MC) by an eco-friendly method. The prepared MC is used to activate peroxydisulfate for eliminating multiple tetracycline antibiotics, such as oxytetracycline (OTC), tetracycline (TTC), and chlortetracycline (CTC) in simulated wastewater under UV-light irradiation. The photoactivated sulfate radical-advanced oxidation processes (SR-AOPs) towards the removal of tetracycline antibiotics matrix (initial concentration of 10.0 mg/L) using MC were initially investigated using a batch method. The results reveal that 97.5% OTC, 95.2% TTC, and 100.0% CTC can be degraded in the MC/UV/PDS system in the presence of 2 g/L of MC and 1 mM of PDS. The degradation pathways of OTC, TTC, and CTC were clarified via liquid chromatography-mass spectrometry analysis and DFT calculations. The quantitative structure–activity relationship analysis shows that the tetracycline antibiotics are transformed into their corresponding intermediates with lower toxicity within 8.0 min. A self-designed fixed bed reactor, in which the MC was packed into the annular channel, was adopted to test the long-term operation possibility of the MC in the continuous photoactivated SR-AOP system. The findings demonstrate that the whole antibiotics matrix can be removed completely within 22 h. This work is the first to demonstrate the use of MOFs as catalysts for SR-AOP to achieve continuous purification of simulated wastewater. The findings highlight a new possibility for the use of MOFs in large-scale wastewater treatment over.
Phase transitions can occur in certain materials such as transition metal oxides (TMOs) and chalcogenides when there is a change in external conditions such as temperature and pressure. Along with phase transitions in these phase change materials (PCMs) come dramatic contrasts in various physical properties, which can be engineered to manipulate electrons, photons, polaritons, and phonons at the nanoscale, offering new opportunities for reconfigurable, active nanodevices. In this review, we particularly discuss phase-transition-enabled active nanotechnologies in nonvolatile electrical memory, tunable metamaterials, and metasurfaces for manipulation of both free-space photons and in-plane polaritons, and multifunctional emissivity control in the infrared (IR) spectrum. The fundamentals of PCMs are first introduced to explain the origins and principles of phase transitions. Thereafter, we discuss multiphysical nanodevices for electronic, photonic, and thermal management, attesting to the broad applications and exciting promises of PCMs. Emerging trends and valuable applications in all-optical neuromorphic devices, thermal data storage, and encryption are outlined in the end.
In this study, magnetic iron-nickel sulfides biochar composites (MINBs) were successfully prepared via one-step solvothermal method and applied to Cr(VI)-containing wastewater treatment. X-ray diffraction (XRD) and scanning electron microscopy (SEM) revealed that synthesized iron-nickel sulfides anchored and dispersed on biochar surface. Cr(VI) removal efficiency and capacity by MINB-5 (molar ratio of Ni to Fe was 5%) were more than 97% and 24.8 mg g-1 within 20 min respectively, when the initial concentration of Cr(VI) was 20 mg L-1. Effects of different operational parameters on Cr(VI) removal efficiency were investigated, including molar ratio of Ni to Fe, dosage of catalyst, initial concentration of Cr(VI), pH value of solution, coexisting ions, natural organic matters (NOMs) and temperature. X-ray photoelectron spectroscopy (XPS) and flame atomic absorption spectrometric (FAAS) analysis demonstrated that Cr(VI) was removed through reduction process by Fe(Ⅱ), which was released from MINBs. Persistent free radicals (PFRs) of biochar, Ni(Ⅱ) and S(-Ⅱ) in MINBs jointly accelerated Fe(Ⅱ)/Fe(III) circulation, instead of direct reduction of Cr(VI) directly. These novel findings provide a new prospect of application of magnetic iron-nickel sulfides biochar composites for Cr(VI)-polluted wastewater remediation.
The hepatoma cell lines stably expressing sodium taurocholate cotransporting polypeptide (NTCP), the receptor of hepatitis B virus (HBV) infection, serve as important infection models for studying viral biology and drug discovery. However, the efficiency of infection greatly varies. In this study, we studied the effects and potential mechanisms of Matrigel® hESC-qualified (M-hq), a biological basement membrane matrix commonly used in cell culture, on promotion HBV in vitro infection in HepG2-NTCP cells. For the first time, our findings demonstrate that M-hq could enhance the infection efficiency of cell culture-derived HBV with no impact on the cell viability, the HBV transcription and response to antiviral treatments. The infection enhancement is reproducible and is suggested to occur at HBV attachment step. Our study suggests that this novel system is applicable for studying HBV biology and new drugs.
Dietary shifts from staples toward meats, fruits, and vegetables increase environmental impacts. Excessive red meat intake and micro-nutrient deficiencies also raise health concerns. Previous research examined environmental and health consequences of alternative diets but overlooked impacts on air pollution and land use change. Here we examine implications of four potential Chinese dietary shifts on ammonia and particulate matter (PM2.5) air pollution, greenhouse gas (GHG) emissions, carbon storage loss associated with land-use change, water use, and human health. We show that a diet that replaces red meat with soy benefits the environment and avoids 57,000 PM2.5-related premature deaths annually. Dietary health benefits, however, appear larger with adoption of the Chinese Dietary Guideline (CDG) and EAT-Lancet diets, which prevent over one million premature deaths annually. However, both diets increase water use and GHGs. CDG also increases COCs, but EAT-Lancet reduces it by cutting dairy and red meat. Complex benefits and trade-offs of dietary shifts emphasize the need for further improvements in agricultural management to enable larger health-environment co-benefits.
Epidermal electronic systems that simultaneously provide physiological information acquisition, processing, and storage are in high demand for health care/clinical applications. However, these system-level demonstrations using flexible devices are still challenging because of obstacles in device performance, functional module construction, or integration scale. Here, on the basis of carbon nanotubes, we present an epidermal system that incorporates flexible sensors, sensor interface circuits, and an integrated flash memory array to collect physiological information from the human body surface; amplify weak biosignals by high-performance differential amplifiers (voltage gain of 27 decibels, common-mode rejection ratio of >43 decibels, and gain bandwidth product of >22 kilohertz); and store the processed information in the memory array with performance on par with industrial standards (retention time of 108 seconds, program/erase voltages of ±2 volts, and endurance of 106 cycles). The results shed light on the great application potential of epidermal electronic systems in personalized diagnostic and physiological monitoring. A CNT-based epidermal system is proposed for physiological signal capturing, processing, and storage.
There are several problems concerning the statistical definition of average bioequivalence provided by U.S. Food and Drug Administration (FDA). We proposed ratio of means based on the original bioavailability measure as the definition for average bioequivalence. Under the log-normal distribution assumption, we proposed a hypothesis testing based method and a confidence interval based methods to answer the question whether the ratio of means falls into a predetermined interval. For the hypothesis testing based method, we decomposed the null two-sided hypothesis of ratio of means into two one-sided hypotheses. With the inter-section union theorem for asymptotic tests, we constructed two asymptotic size-$\alpha$ tests for the original null hypothesis. Method of variance estimation recovery was adopted to develop the confidence interval based method. Simulation studies showed that the proposed methods can maintain the empirical type-I error rate closely at the nominal level and is as powerful as two one-sided $t$-test for testing the ratio of means under different settings. The application of the proposed methods was illustrated through 6 datasets in real-world examples.
The semi-open character with high passenger flow in Metro Rail Transport Stations (MRTS) makes safety management of human-electromechanical interaction escalator systems more complex. Safety management should not consider only single failures, but also the complex interactions in the system. This study applies task driven behavior theory and system theory to reveal a generic framework of the MRTS escalator accident mechanism and uses Lasso-Logistic Regression (LLR) for escalator injury prediction. Escalator accidents in the Beijing MRTS are used as a case study to estimate the applicability of the methodologies. The main results affirm that the application of System-Theoretical Process Analysis (STPA) and Task Driven Accident Process Analysis (TDAPA) to the generic escalator accident mechanism reveals non-failure state task driven passenger behaviors and constraints on safety that are not addressed in previous studies. The results also confirm that LLR is able to predict escalator accidents where there is a relatively large number of variables with limited observations. Additionally, increasing the amount of data improves the prediction accuracy for all three types of injuries in the case study, suggesting the LLR model has good extrapolation ability. The results can be applied in MRTS as instruments for both escalator accident investigation and accident prevention.