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Industrial discharges might be responsible for perfluoroalkyl acid pollution. More attention must be paid to perfluoroalkyl acid risks to children in typical drinking water sources of Shandong Province in China.

Understanding how the morphology of a layered double hydroxide (LDH)-based catalyst alters its catalytic activity provides an available strategy for the rational design and fabrication of high-efficiency catalysts at a micro-scale. Herein, three nickel-iron layered double hydroxide (NiFe-LDH) catalysts including 2D-plate-like hexagon (P-NiFe-LDH), 2D/3D-flower-like solid sphere (FS-NiFe-LDH), and 2D/3D-flower-like hollow sphere (FH-NiFe-LDH) with regulable oxygen vacancies (OVs) were fabricated via a morphological regulation method of Ostwald ripening. The experimental results demonstrated that the three types of NiFe-LDH exhibited different abilities to activate persulfate (PS) for the abatement of acid orange 7 (AO7) with a sequence of FH-NiFe-LDH FS-NiFe-LDH P-NiFe-LDH. Particularly, the FH-NiFe-LDH with a hollow structure exhibited the most considerable activity with the first-order rate constant up to k = 0.02639 min

Phosphate residue is a kind of hazardous solid waste and if not properly disposed of, could cause serious environmental contaminations. The abundant iron salt available in phosphate residue can be used to prepare photo-Fenton catalytic reagent for wastewater treatment. In this study, the phosphate residue was effectively purified by a hydrothermal recrystallization method, reaching an iron phosphate purity of 94.2%. The particles of iron phosphate were further processed with ball milling with their average size reduced from 19.4 to 1.6 μm. By hydrothermal crystallization of iron phosphate and thermal decomposition of oxalate precursor, porous iron hydroxy phosphate was prepared. The modified porous iron hydroxy phosphate (m-PIHP) of higher surface area with iron oxalate on its surface can degrade 98.87% of Rhodamine B in 15 min. Cyclic experiment showed that the catalyst still had a good catalytic activity after six cycles (>40%). The X-ray photoelectron spectroscopy results showed that the iron oxalate complex on the catalyst surface decomposed to produce ferrous ions and accelerated the rate of •OH production. The current work demonstrated that the m-PIHP synthesized from phosphate residue and modified with iron oxalate can be used as an effective dye wastewater treatment agent.

A series of LaNiO3 perovskite nanoparticles with different morphologies, such as spheres, rods and cubes, were prepared through co-precipitation and hydrothermal methods, and used as the catalysts for peroxydisulfate (PDS) activation. The physical and chemical characterization of LaNiO3 perovskites was performed, including X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen isotherm absorption (BET), electrochemical impedance spectroscopy (EIS), and X-ray photoelectron spectroscopy (XPS). The LaNiO3 with different shapes showed different activities in Acid Orange 7 (AO7) degradation. Sphere-like LaNiO3 exhibited the highest catalytic activity, which is probably due to the largest specific surface area, higher proportion of reductive Ni2+ and the higher electron transfer ability. The radical scavenging experiments and electron paramagnetic resonance (EPR) revealed the production of massive sulfate radicals (SO4•−) and hydroxyl radicals (•OH) during the oxidation. Finally, the possible mechanisms of PDS activation and AO7 degradation were proposed. The prepared LaNiO3 perovskites also showed excellent reusability and stability. HIGHLIGHTS Three LaNiO3 perovskites with different morphologies were synthesized.; Sphere-like LaNiO3 exhibited the highest catalytic activity for activating PDS.; Produced •OH and SO4•− were main active species in the reaction system.; The mechanism of AO7 degradation reaction in the system was proposed.; LaNiO3 can be reused for multiple cycles to activate PDS for AO7 degradation.

A series of FeMn bimetallic ferrocene-based metal-organic frameworks (FeMn-Fc-MOFs) with various molar ratios of Fe and Mn (1:9, 2:8, 4:6, 6:4) were successfully synthesized using a simple hydrothermal synthesis method and employed as an efficient activator on persulfate (PS) activation for water decontamination. Characterizations demonstrated that Fe and Mn were smoothly introduced into ferrocene-based MOFs and various molar ratios of Fe:Mn had some influence on crystallinity and surface structure of FeMn-Fc-MOFs. Within 120 min, Fe4Mn6-Fc-MOFs demonstrated the best catalytic activity among the different molar ratios, and acid orange 7(AO7) degradation rate was up to 92.0%. In addition, electrochemical experiments revealed that Fe4Mn6-Fc-MOFs possessed superior electron transfer capability than other FeMn-Fc-MOFs, leading to better catalytic performance. Moreover, quenching tests and electron paramagnetic resonance (EPR) detection indicated that hydroxyl radicals and sulfate radicals were both responsible for AO7 decomposition. Notably, the redox cycle of Fe(II)/Fe(III) and Mn(II)/Mn(IV) was discovered in the Fe4Mn6-Fc-MOFs/PS system, which was considered as the limiting process for the cleavage of the O-O bond in PS to generate active radicals. Ultimately, the Fe4Mn6-Fc-MOFs exhibits an excellent universality and good cycling stability for 5 continuous runs. This paper broadens the application of ferrocene-based MOFs on heterogeneous PS activation in environmental catalysis.

Image fusion has been developing into an important area of research. In remote sensing, the use of the same image sensor in different working modes, or different image sensors, can provide reinforcing or complementary information. Therefore, it is highly valuable to fuse outputs from multiple sensors (or the same sensor in different working modes) to improve the overall performance of the remote images, which are very useful for human visual perception and image processing task. Accordingly, in this paper, we first provide a comprehensive survey of the state of the art of multi-sensor image fusion methods in terms of three aspects: pixel-level fusion, feature-level fusion and decision-level fusion. An overview of existing fusion strategies is then introduced, after which the existing fusion quality measures are summarized. Finally, this review analyzes the development trends in fusion algorithms that may attract researchers to further explore the research in this field.

Camera pose optimization is the basis of geometric vision works, such as 3D reconstruction, structure from motion, and visual odometry. A pose optimization method based on learned metrics is proposed to improve the optimization convexity. The neural network was designed and trained based on the collected datasets, respectively. The network inputs pairwise patches and outputs the Euclidean distance of its center. This distance is involved in the residual calculation of Gauss-Newton, and the Jacobian corresponding to this distance can be analytically solved. The simulation verified convergence and generalization of the designed network. The accuracy and robustness of the proposed pose optimization compared with intensity- and feature-based optimizations are also verified.

Ferrocene-based metal-organic framework with different transition metals (M-Fc-MOFs, M=Fe, Mn, Co) were synthesized by a simple hydrothermal method and used as a heterogeneous catalyst for persulfate activation. The samples were characterized by X-ray diffraction, transmission electron microscopy, X-ray electron spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy. Meanwhile, the influences of factors such as catalyst dosage, persulfate concentration and pH on the degradation of acid orange 7 (AO7) were studied in detail. The results showed that hollow cobalt-based ferrocenyl metal-organic framework microspheres (Co-Fc-MOFs) exhibited the best catalytic performance, which is closely related to the synergy of Fc/Fc+ and Co2+/Co3+ cycles in persulfate activation. Free radical quenching studies indicated that both sulfate and hydroxyl appeared to contribute to the degradation of AO7.

Ferrocene-based metal-organic framework with different transition metals (M-Fc-MOFs, M = Fe, Mn, Co) was synthesized by a simple hydrothermal method and used as a heterogeneous catalyst for persulfate activation. The samples were characterized by X-ray diffraction, transmission electron microscopy, X-ray electron spectroscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. Meanwhile, the influences of factors such as catalyst dosage, persulfate concentration, and pH on the degradation of acid orange 7 (AO7) were studied in detail. The results showed that hollow cobalt-based ferrocenyl metal-organic framework microspheres (Co-Fc-MOFs) exhibited the best catalytic performance, which is closely related to the synergy of Fc/Fc

AimsAlpha-thalassaemia is one of the most common monogenic disorders worldwide. Due to high guanine-cytosine (GC) content and high mutation diversity in α-globin gene cluster, deletional and non-deletional mutations were usually separately detected with different methods. The aim of this study was to develop a novel one-step method for α-thalassaemia genotyping.MethodsA multiplex symmetric PCR melting curve strategy was designed for one-step α-thalassaemia genotyping. Based on this strategy, a novel method was developed to simultaneously detect four common deletional (-α3.7, -α4.2, _ _SEA, --THAI) and five common non-deletional (αCD30(-GAG)α, αCD31(G>A)α, αWSα, αQSα, αCSα) α-thalassaemia mutations in a closed-tube reaction. This method was also evaluated by double-blind detection of 235 genotype-known samples and 1630 clinical samples.ResultsAll nine α-thalassaemia mutations could be accurately identified by this novel method within 3 hours. The evaluation results also showed a 100% concordance with comparison methods.ConclusionsThis method is rapid, accurate, low-cost and easy to operate, which can be used for molecular screening and genetic diagnosis of α-thalassaemia in clinical practice. The multiplex symmetric PCR melting curve strategy designed in this study can also provide an effective approach to the method development for high GC content templates and multiple mutations.

Goethite is the most ubiquitous iron oxide mineral in soils, and adsorption of organic pollutants on goethite dominates the fate and transportation in the environment. In this study, the facet-dependent adsorption behavior of ciprofloxacin (CIP) on goethite was systematically investigated with in situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectra and two-dimensional correlation analysis (2D-COS). The experimental results indicated that the goethite samples with higher facet proportion of {021}/{110} exhibited the better adsorption capacity compared to goethite with lower facet proportion of {021}/{110}. The reason is the more existence of singly coordinated sites with higher reactivity on the {021} facet. Moreover, CIP was found to be adsorbed on {021} and {110} facets by forming a tridentate complex involving the bridge coordination of bidentate ligands, H-bonding, and a bidentate chelate complex.

In this work, four novel defective MIL-101(Fe) catalysts with coordinatively unsaturated sites were successfully prepared via a facile synthesis strategy by employing benzoic acid, acetic acid, oxalic acid, or citric acid as a modulator. The modified catalysts were demonstrated the existence of defects in the parent framework by a series of characterizations. As compared to the initial MIL-101(Fe), the electronic structure of defective MIL-101(Fe) catalyst was effectively adjusted; meanwhile, the coordinatively unsaturated Fe sites were efficiently generated and the pore sizes were enlarged. Besides, the defective MIL-101(Fe) catalysts exhibited excellent catalytic performance for rhodamine B degradation by persulfate activation. To be specific, the degradation rates of rhodamine B increased from 58.70 to 94.05%, 86.11%, 78.70%, and 82.62%, respectively. The defective MIL-101(Fe) with coordinatively unsaturated sites showed good reusability and stability, and the probable catalytic mechanism was also investigated.

In this work, a series of La-doped NiFe-layered double hydroxides containing a novel Keggin type polyoxometalate interlayer (NiFeLa{HPW}-LDH) were synthesized and initially applied as heterogeneous catalyst for peroxymonosulfate (PMS) activation. Characterizations indicated that polyoxometalate anions were successfully intercalated in the layers of NiFeLa-LDH. Experiment results showed that NiFeLa{HPW}-LDH exhibited better catalytic performance than the counterpart precursor. The influences of various experimental parameters, such as pH value, initial TC concentration, HPW intercalation content, catalyst loading and peroxymonosulfate concentration were investigated in detail. Quenching experiments and the results of electron paramagnetic resonance (EPR) demonstrated the SO4− and HO were the dominant reactive radicals engaging in the degradation process. Furthermore, the formation of a complex of Ni(II)/Fe(II)/La(III)−(HO)OSO3− and the succeeding redox cycle of Ni(II)/Ni(III)/Ni(II), Fe(II)/Fe(III)/Fe(II), La(III)/La(IV)/La(III) were responsible for the generation of active radicals via activating PMS. Meanwhile, it's worth noting that the intercalated HPW also played a vital role in electron transfer.

The three-dimensional graphene microspheres with well-defined shape and size were prepared successfully by a novel approach, i.e., a combination of microfluidic device and freeze-drying. In the synthetic process, a pragmatic and facile device has been designed for the controllable generation of uniform-sized droplets. Followed by freeze-drying, highly porous spherical graphene microballs were obtained for further research. It is worth noting that the size of the droplets can also be controlled by adjusting the flow rate ratio of each phase. Afterward, the morphology, structure and character of the three-dimensional graphene particles are characterized by scanning electron microscope, X-ray diffraction, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Due to their highly porous structure, the as-prepared 3D graphene microspheres were employed as adsorbent. The adsorption capacity of acid orange 7 and Pb(II) was about 71.9 and 147.7 mg g−1, respectively. The results showed that the porous 3D graphene microspheres as adsorbent possessed excellent adsorption ability for organic and inorganic contaminants in this work, showing their potential applications in environmental pollutant treatment.

In this study, a novel composite containing an iron based metal-organic framework (MOF) and BiOBr was successfully synthesized by a simple method, and was fully characterized by X-ray diffraction patterns, Fourier transform infrared spectra, UV-vis diffuse reflectance spectra, and transmission electron microscopy. Moreover, the photocatalytic activities of BiOBr/MIL-88B(Fe) composites and the pure materials were evaluated by measuring the degradation of Rhodamine B under visible light. The results show that the composite exhibits better photocatalytic activities than pure materials, which can be ascribed to the high adsorption capacity of MIL-88B(Fe) and the enhanced separation of photogenerated charge carriers from assembly of MIL-88B(Fe) on BiOBr. And the effects of various operating parameters such as catalyst dosage, medium pH, the mass ratio of BiOBr, and MIL-88B(Fe) and the dye initial concentration on the degradation of RhB have been studied.

Materials based on phosphotungstic acid (H3PW12O40, HPW) encapsulated in metal organic framework MIL-53(Fe) were prepared by a simple solvothermal method. The as-synthesized samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectra, and UV–vis diffuse reflectance spectroscopy method. The resulting materials were evaluated in the photodecomposition of cationic dye Rhodamine B (RhB) under visible light irradiation. A Light-emitting diodes lamp was used as visible light source. The results showed that the composites exhibited better photocatalytic activities than pure materials. A possible photocatalytic reaction mechanism has been investigated. The formation of active oxygen species such as •OH and • O2−, which are detected during the degradation of RhB, is proposed to be responsible for the degradation of RhB. In addition, the HPW@MIL-53(Fe) photocatalyst exhibited good chemical stability after five consecutive degradation cycles. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 1342–1350, 2017

A novel quinone-modified metal-organic frameworks NH2-MIL-101(Fe) was synthesized using a simple chemical method under mild condition. The introduced 2-anthraquinone sulfonate (AQS) can be covalently modified with NH2-MIL-101(Fe) and acts as a redox mediator to enhance the degradation of bisphenol A (BPA) via persulfate activation. The obtained AQS-NH-MIL-101(Fe) was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectra, cyclic voltammetry and electrochemical impedance spectroscopy. AQS-NH-MIL-101(Fe) exhibited better catalytic performance compared with NH2-MIL-101(Fe) and NH2-MIL-101(Fe) with free AQS (NH2-MIL-101(Fe)/AQS). That is, AQS-NH-MIL-101(Fe) was proved to be the most effective in that more than 97.7% of BPA was removed. The degradation rate constants (k) of AQS-NH-MIL-101(Fe) was 9-fold higher than that of NH2-MIL-101(Fe) and 7-fold higher than NH2-MIL-101(Fe)/AQS, indicating that AQS is a great electron-transfer mediator when modified with NH2-MIL-101(Fe). Based on the above results, the possible mechanism of catalytic reaction has been investigated in view of the trapping experiments. In addition, the AQS-NH-MIL-101(Fe) catalyst exhibited excellent stability and can be used several times without significant deterioration in performance.

Self-propelled metal–organic framework (MOF)-based Janus micromotors that propel autonomously in hydrogen peroxide and display effective remediation of contaminated water is presented in this work. The novel Janus micromotors rely on the asymmetric deposition of a catalytically active Ag patch on the surface of MOF composite microspheres. The active Ag sites are used for the splitting of H2O2 to form oxygen bubbles. As a result, these Janus micromotors can reach a high speed of over 310 μm s−1 due to effective bubble propulsion, which is comparable to common Pt-based micromotors. By coupling the high catalytic capacity of MOFs with their autonomous propulsion, the MOF-based micromotors are shown to play a dominant role in the effective removal of organic pollutants. In addition, scanning electronic microscopy, Fourier-transform infrared spectroscopy and energy dispersive X-ray spectroscopy are performed to verify their morphology and composition. Based on the obtained results, a potential mechanism of the motion and the high catalytic activity is also proposed. It is expected that these energy saving micromotors with catalytic activity should be unprecedentedly spread in real applications.

Photovoltaic (PV) power short-term forecasting is of great significance to power system control and operations. To improve the forecasting accuracy, this paper proposes a machine-learning-based short-term forecasting approach for PV power. The proposed approach is built on multiple sub-models which contribute to high prediction accuracy. Firstly, a training set is used to build sub-models with better performance. Secondly, each sub-model is fused by an equal weight fusion method or a least square method, and the integrated model generates the prediction results. Finally, the effectiveness of the method is verified by an example. The simulation results verify that the proposed forecasting approach has a better prediction performance than the equal weight synthesis methods and an improved prediction accuracy than the traditional method.

To realize the error parameter estimation of strap-down inertial navigation system (SINS) and improve the navigation accuracy for aircraft, a hybrid improved restricted Boltzmann machine BP neural network (IRBM-BPNN) approach, which combines restricted Boltzmann machine (RBM) and BP neural network (BPNN), is proposed to forecast the inertial measurement unit (IMU) instrument errors and initial alignment errors of SINS. Firstly, the error generation mechanism of SINS is analyzed, and initial alignment error model and IMU instrument error model are established. Secondly, an unsupervised RBM method is introduced to initialize BPNN to improve the forecast performance of the neural network. The RBM-BPNN model is constructed through the information fusion of SINS/GPS/CNS integrated navigation system by using the sum of position deviation, the sum of velocity deviation and the sum of attitude deviation as the inputs and by using the error parameters of SINS as the outputs. The RBM-BPNN structure is improved to enhance its forecast accuracy, and the pulse signal is increased as the input of the neural network. Finally, we conduct simulation experiments to forecast and compensate the error parameters of the proposed IRBM-BPNN method. Simulation results show that the artificial neural network method is feasible and effective in forecasting SINS error parameters, and the forecast accuracy of SINS error parameters can be effectively improved by combining RBM and BPNN methods and improving the neural network structure. The proposed IRBM-BPNN method has the optimal forecast accuracy of SINS error parameters and navigation accuracy of aircraft compared with the radial basis function neural network method and BPNN method.