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[Display omitted] • MIL-88B(Fe)/Fe 3 S 4 hybrids for effective water treatment by heterogeneous electro-Fenton. • Hybrid catalyst: highly uniform composition due to excellent distribution of small Fe 3 S 4. • Sulfidation allows breaking the activity-stability trade-off for high performance HEF. • Good recyclability of hybrids and fast trimethoprim removal even in urban wastewater. • Great catalytic activity and degradation mechanism confirmed by DFT calculations. Fe-based metal–organic frameworks are promising catalysts for water treatment, although their viability is hampered by the slow regeneration of active Fe(II) sites. A facile sulfidation strategy is proposed to boost the catalytic activity of MIL-88B(Fe) in heterogeneous electro-Fenton (HEF) treatment of organic micropollutants at mild pH. The synthesized MIL-88B(Fe)/Fe 3 S 4 hybrids possessed numerous and durable unsaturated iron sites, acting the S2− atoms as electron donors that enhanced the Fe(II) recycling. The sulfidated catalyst outperformed the MIL-88B(Fe), as evidenced by the 7-fold faster degradation of antibiotic trimethoprim by HEF and the fast destruction of micropollutants in urban wastewater. The hybrid catalyst was reused, obtaining >90% drug removal after four runs and, additionally, its inherent magnetism facilitated the post-treatment recovery. Electrochemical tests and DFT calculations provided mechanistic insights to explain the enhanced catalysis, suggesting that the accelerated Fe(III)/Fe(II) cycling and the enhanced mass transport and electron transfer accounted for the efficient trimethoprim degradation. [ABSTRACT FROM AUTHOR]

The effects of electrochemical oxidation (EO), Fered-Fenton and solar Fered-Fenton processes using a recirculation flow system containing an electrochemical cell and a solar photo-reactor on biochemically treated landfill leachate were investigated. The most successful method was solar Fered-Fenton which achieved 66.5% COD removal after 120 min treatment utilizing the optimum operating conditions of 47 mM H 2 O 2 , 0.29 mM Fe 2+ , pH 0 of 3.0 and a current density of 60 mA/cm 2 . The generation of hydroxyl radicals ( OH) are mainly from Fered-Fenton process, which is enhanced by the introduction of renewable solar energy. Moreover, Fe 2+ /chlorine and UV/chlorine processes taking place in this system also result in additional production of OH due to the relatively high concentration of chloride ions contained in the leachate. The energy consumption was 74.5 kWh/kg COD and the current efficiency was 36.4% for 2 h treatment. In addition, the molecular weight (MW) distribution analysis and PARAFAC analysis of excitation emission matrix (EEM) fluorescence spectroscopy for different leachate samples indicated that the organics in the leachate were significantly degraded into either small molecular weight species or inorganics. [ABSTRACT FROM AUTHOR]

A time-domain hybrid method is presented for efficiently solving the coupling problems of long cables above the ground excited by electromagnetic pulses. The proposed method is combined with transmission-line (TL) equations, finite-difference time-domain (FDTD) method, and a novel fast calculation approach for excitation fields of long cables. In this hybrid method, the effect of the ground on the incident wave is equivalent to a time-domain reflection wave source, and the excitation fields of long cables are computed by the superposition of electric fields created by the incident and reflection wave sources. Then, the TL equations are employed to build the coupling model of long cables and the excitation fields are introduced into the TL equations as distribution sources. Finally, the transient responses on long cables are obtained by the TL equations with the FDTD method. Two examples are given to demonstrate the accuracy and high efficiency of this method. It shows that this method can tremendously decrease the memory requirement and computation time compared with the FDTD method, and has the ability of fast simulating the coupling problem of long cables excited by multiple pulse sources. [ABSTRACT FROM PUBLISHER]

This paper presents a novel time domain hybrid method consisting of finite-difference time domain (FDTD) method, transmission line (TL) equations, and circuit-based method, which can be directly applied in time domain for the electromagnetic interference (EMI) analysis of the lumped circuits in a shielded device excited by ambient electromagnetic wave. The FDTD method coupled with the TL equations is utilized to model the electromagnetic properties of arbitrary structures containing transmission lines and shielded enclosure of the electronic device with any ambient excitation. With numerical simulation, an equivalent circuit model considering the external EMI effects is extracted as an excitation source for the internal lumped circuit according to Thevenin's theorem. Then, the state variable approach is used for the further EMI analysis of the internal lumped circuit in time domain. Two cases, in which a transmission line and/or a transmission line network are connected to a lumped circuit within a shielded enclosure excited by an intense electromagnetic pulse, are computed with the proposed method. The numerical results are compared with those obtained by using the FDTD method, and they are almost in perfect agreements. Meanwhile, at last, an example of this method applied for the EMI protection of an electronic device is given. [ABSTRACT FROM AUTHOR]

Aims The purpose of this paper was to fabricate PLLA/PCL nanofibrous scaffolds containing HAP to mimic the native bone extracellular matrix for potential applications as bone tissue engineering scaffolds materials and ultimately to help the repairing of bone defects. Materials and methods PLLA (MW 200 kDa), PCL (MW 80 kDa), HAP, dichloromethane, N , N -dimethylformamide; α-MEM, FBS, trypsin-EDTA, penicillin G, streptomycin, β-sodium glycerophosphate, l -ascorbic acid, dexamethasone; CCK-8, Alkaline Phosphatase Assay Kit, Mouse Osteocalcin ELISA Kit, MC3T3-E1 cells. PLLA, PCL and HAP were dissolved in the solution of DCM and DMF to fabricate nanofibrous scaffolds through electrospinning. The morphology of the scaffolds was investigated with SEM, while the diameter of the fibers, pore size and water uptake of the scaffolds were tested, respectively. TGA was carried out to verify the percentage of HAP in the composite scaffolds fabricated with different HAP concentrations. Cell count kit-8 assay, alkaline phosphatase (ALP) assay, and osteocalcin assay were applied to observe the MC3T3-E1 cells proliferation, differentiation on the composite scaffolds. Key findings MC3T3-E1 cells were found to grow actively on the composite scaffolds based on the results of CCK-8 assay. The level of MC3T3-E1 differentiation was evaluated through the ALP activity and osteocalcin concentration, which showed higher value with HAP containing (PLLA/PCL/HAP) than that ones without (PLLA/PCL). Significance The results demonstrated that the biocomposite PLLA/PCL/HAP nanofibrous scaffold should be a promising candidate for proliferation, differentiation and mineralization of osteoblasts, and potentially can be used for bone tissue regeneration. [ABSTRACT FROM AUTHOR]

Ammonium ion-exchange performance of the natural zeolite was investigated in both batch and column studies. The effects of zeolite dosage, contact time, stirring speed and pH on ammonium removal were investigated in batch experiments. The result showed that ammonium removal efficiency increased with an increase in zeolite dosage from 25 to 150 g/L, and an increase in stirring speed from 200 to 250 r/min. But further increase in zeolite dosage and stirring speed would result in an unpronounced increase of ammonium removal. The optimal pH for the removal of ammonium was found as 7.1. In the column studies, the effect of flow rate was investigated, and the total ammonium removal percentage during 180 min operation time decreased with the flow rate though the ion-exchange capacity varied to a very small extent with the flow rate ranging from 4 to 9 mL/min. The spent zeolite was regenerated by sodium chloride solution and the ammonia removal capacity of zeolite changed little or even increased after three regeneration cycles. [ABSTRACT FROM PUBLISHER]

Background and aims: Rice contaminated by mercury [Hg, especially methylmercury (MeHg)] has given rise to great concern in recent years. This study investigated variations in ecophysiological features (anatomy, organic acid secretions, Fe plaque formation) of rice roots and their effects on the uptake and accumulation of total mercury (THg) and MeHg by rice plants. Methods: The development of apoplastic barriers in roots of four rice cultivars was observed by a hydroponic experiment while the concentrations of five organic acids, Fe and THg in Fe plaque were determined using a rhizobag trial with different Hg treatments. Results: Cultivars with low Hg accumulation tended to develop strong apoplastic barriers in endodermis, secrete less organic acids and form more Fe plaque on root surfaces and in rhizosphere. Fe concentrations were positively correlated with THg concentrations in rhizosphere's Fe plaque (R = 0.60, P < 0.01), whereas the latter was negatively correlated with bioavailable Hg concentrations in rhizosphere (R = 0.40, P < 0.01). Conclusions: Organic acids and Fe plaque formation of rice roots play important roles in Hg uptake and accumulation. The development of apoplastic barriers in root restricts Hg uptake but the significance of suberin deposition on Hg uptake needs further investigations. [ABSTRACT FROM AUTHOR]

ABSTRACT In this study, the strong-acid polystyrene resin D001 was modified by impregnation with metal ions Fe3+, Cu2+, and Zn2+ to prepare new kinds of sorbents. The modified D001 was characterized by N2 sorption-desorption isotherms, X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The sorption performance of the metal modified resins for removal of antibiotics tetracycline (TC) and doxycycline (DC) from aquatic environment was investigated and excellent sorption capability with more than 98% removal ratio was observed for these resins after modification. Although these modified resins also presented pH-dependent sorption, they showed much better flexibility with pH fluctuation than those of the unmodified original D001, and extremely strong sorption capability was exhibited in a wide range of pH 2-8 for both TC and DC. Pseudo-second-order kinetic equation described the sorption process more reasonably than pseudo-first-order equation. Langmuir isotherm model provided the best match to the equilibrium data with monolayer maximum sorption capacity of 417-625 mg g−1 under 288-318 K. The sorption capacity decreased with the increase of ionic strength of NaCl. The main sorption mechanism was proposed to be surface complexation, cation bridge interaction and electrostatic attraction/competition between antibiotics and metal modified resins. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41803. [ABSTRACT FROM AUTHOR]

Constructed wetlands used to clean up toxic metals such as lead (Pb) from contaminated wastewater are considered as an effective and low-cost technology. The effect of Pb on the biomass, tolerance, soluble protein, and antioxidant enzymes in 18 candidate wetland plant species grown in soils without (control) and spiked with 900 and 1800 mg Pb kg was studied in a pot trial. Our pot experiment showed that the biomass, tolerance, and leaf protein contents decreased with increasing concentrations of Pb in soil. There were significant differences between the plants in their Pb tolerance indices (29-82 % in the 900 mg Pb kg amended soil) and also Pb uptake (13-749 mg kg in shoots and 1112-4891 mg kg in roots, in the same treatments). Activities of superoxide dismutase (SOD) and peroxidase (POD) in leaves of most of the plants increased with increasing level of soil Pb concentration. Conversely, catalase (CAT) activity in leaves declined when plants were subjected to Pb stress. Lead accumulation by the 18 wetland plant species screened was strongly dependent on the species and Pb concentrations in the soil. However, Pb translocation from root to shoot was generally low in all species. Increases in SOD and POD activities suggest that the antioxidant system may play an important role in alleviating Pb toxicity in wetland plants. The data obtained should help in future species selection for the use in designing wetlands in Pb-contaminated environments. [ABSTRACT FROM AUTHOR]