Capture and separation of CO2 on BC3 nanosheets: A DFT study

In order to reduce the greenhouse effect caused by the rapid increase of CO₂ concentration in the atmosphere, it is necessary to develop more efficient, controllable, and highly sensitive adsorbing materials. In this study, the adsorption behavior of CO₂ on BC₃ nanosheets under an external electric field was explored based on density functional theory (DFT). It was found that CO₂ experienced a transition from physisorption to chemisorption in the electric field range of 0.0060-0.0065 a.u.. In addition, the adsorption/desorption of CO₂ is reversible and can be precisely controlled by switching on/off at the electric field of 0.0065 a.u.. The selective adsorption of CO₂/H₂/CH₄ by BC₃ can also be used to realize gas separation and purification under different electric fields. This study highlighted the potential application of BC₃ nanosheets as a high-performance, controllable material for CO₂ capture, regeneration, and separation in an electric field.     

Removal of pesticide chlorobenzene by anodic degradation: Variable effects and mechanism

The oxidation of chlorobenzene (CB) was studied by electrochemical electrolysis using boron-doped diamond (BDD), PbO₂ or platine (Pt) as anode and graphite bar as cathode. The effect of applied current density, supporting electrolyte and initial pH value were also studied. The results demonstrated that BDD anode had the best effectiveness and accomplishment of electrochemical degradation of CB compared to PbO₂ and Pt anodes. For a current density of 20 mA/cm² and at pH = 3, the elimination of COD and TOC were about 97% and 98%, respectively, after 360 min of electrolysis with the BDD anode. Pseudo-first order kinetics appears to be the most appropriate to describe the degradation of chlorobenzene. The electrochemical mechanism of chlorobenzene on BDD was proposed based on the identified intermediates.     

Boron-doped diamond electrodes for the mineralization of organic pollutants in the real wastewater

The presence of recalcitrant organic compounds in wastewater poses a serious threat to the ecosystem and human health. Electrochemical advanced oxidation processes constitute a promising way for the mineralization of persistent organic compounds. They are commonly used for the transformation of organic pollutants into more biodegradable compounds or their complete removal from water. In this review, we present the recent advances in the use of boron-doped diamond (BDD) electrodes in the anodic oxidation process for the mineralization of real wastewater. First, the characteristic properties of BDD electrodes are discussed followed by the degradation mechanism. In addition, an overview on the application of BDD electrodes for mineralization of real wastewater is provided.     

Application of boron-doped diamond electrodes for electrochemical oxidation of real wastewaters

Recently, the synthesis of boron-doped diamond electrodes on different substrates and shapes have reached a promising development stage. Now, these electrodes can also be effectively used to destroy toxic or biorefractory organics in real effluents, such as municipal wastewaters effluents, hospital wastewaters, groundwater, petrochemical effluent, wastewaters from agri–food activities, and so on. The results of this mini-review show that BDD is effectively even for such real effluents, allowing the removal of pollutants under several different conditions. Nevertheless, further efforts are necessary to reach a wider market; in particular, the next stages must face the optimization of cell design and the integration of the electrochemical system with other water treatment and renewable energy sources.     

Electrochemical oxidation of organic pollutants in low conductive solutions

This mini-review supplies current opinion about the most recent works, which have been carried out toward the electrochemical treatment of organic compounds spike in low conductive solution. In particular, the first section is focused on the use of a solid polymer electrolyte in order to allow current flux with a low cell voltage even in a solution without supporting electrolyte. Meanwhile, the second section describes the microfluidic cells that are characterized by very small distances between electrodes (tens or few hundreds μm) that reduce the ohmic resistances and increase the mass transport of the pollutants to electrodes’ surfaces.     

The high concentration and uniform distribution of diamond particles in Ni‐diamond composite coatings by sediment co‐deposition

Ni‐diamond composite coatings with high concentration and uniform distribution of diamond particles were prepared by using sediment co‐deposition (SCD) technique from Watts‐type electrolyte without any additives. The surface and cross‐section morphology was evaluated by optical microscope (OM) and scanning electron microscopy (SEM). It was demonstrated that the Ni‐monolayer diamond composite coatings ~40 ± 5 µm was successfully prepared by the new developed setup for SCD technique. Using this new developed setup, high concentration and uniform distribution of diamond particles of Ni‐monolayer diamond composite coatings were easily fabricated. The wear resistance and cutting performance of obtained composite coatings were also investigated. The results revealed that anti‐wear and cutting performance is superior to those prepared via conventional co‐electrodeposition (CED) technique and pure Ni coatings. In the SCD process, with the increasing diamond content, the wear resistance is approximately the same, and the cutting performance decreases. Therefore, not only the diamond particle content is responsible for the wear resistance and cutting performance, the distribution of diamond particles is also very important factor. Copyright © 2014 John Wiley & Sons, Ltd.     

含树枝化以及线性侧链的超分子共聚物的液晶相结构调控

设计了一类由聚4-乙烯基吡啶(P4VP)、含弯曲树枝化分子12CBP以及线性分子PDP组成的三元共混体系,其中12CBP和PDP端基均为酚羟基,可与P4VP侧基的吡啶环上的N原子进行氢键复合.傅立叶变换红外光谱、示差扫描量热法、偏光显微镜、小角X射线散射和原子力显微镜等多种研究表明该共混体系为均相体系,三组分自组装形成以P4VP为主链,12CBP和PDP为超分子侧链的"无规共聚物"P4VP(12CBP)x(PDP)y(x+y=1).该超分子侧链共聚物的聚集态结构与小分子12CBP和PDP相对含量有关.当12CBP含量x≥0.5时,体系组装形成六方柱状相结构,柱子的直径随着体系中12CBP含量减少而逐渐减小.当12CBP含量0.5时,即使少量12CBP的引入也会引起体系层状相结构的破坏,体系表现为无定形状态.     

Voltammetric Method for the Simultaneous Determination of Melatonin and Pyridoxine in Dietary Supplements Using a Cathodically Pretreated Boron‐doped Diamond Electrode

The simultaneous voltammetric determination of melatonin (MT) and pyridoxine (PY) has been carried out at a cathodically pretreated boron‐doped diamond electrode. By using cyclic voltammetry, a separation of the oxidation peak potentials of both compounds present in mixture was about 0.47 V in Britton‐Robinson buffer, pH 2. The results obtained by square‐wave voltammetry allowed a method to be developed for determination of MT and PY simultaneously in the ranges 1–100 μg mL⁻¹ (4.3×10⁻⁶–4.3×10⁻⁴ mol L⁻¹) and 10–175 μg mL⁻¹ (4.9×10⁻⁵–8.5×10⁻⁴ mol L⁻¹), with detection limits of 0.14 μg mL⁻¹ (6.0×10⁻⁷ mol L⁻¹) and 1.35 μg mL⁻¹ (6.6×10⁻⁶ mol L⁻¹), respectively. The proposed method was successfully to the dietary supplements samples containing these compounds for health‐caring purposes.     

Impact of high N2 flow ratio on the chemical and morphological characteristics of sputtered N‐DLC films

Because of their outstanding characteristics, diamond‐like carbon (DLC) thin films have been recognized as interesting materials for a variety of applications. For this reason, the effects of the incorporation of different elements on their fundamental properties have been the focus of many studies. In this work, nitrogen‐incorporated DLC films were deposited on Si (100) substrates by DC magnetron sputtering of a graphite target under a variable N₂ gas flow rate in CH₄ + N₂ + Ar gas mixtures. The influence of high N₂ flow ratios (20, 40 and 60%) on the chemical, structural and morphological properties of N‐DLC films was investigated. Different techniques including field emission gun‐equipped scanning electron microscope (FEG‐SEM), energy‐dispersive X‐ray spectroscopy (EDS), atomic force microscopy (AFM), profilometry, Rutherford backscattering spectrometry (RBS) and Raman spectroscopy (325‐nm and 514‐nm excitation) were used to examine the properties of the N‐DLC films. Thus, the incorporation of nitrogen was correlated with the morphology, roughness, thickness, structure and chemical bonding of the films. Overall, the results obtained indicate that the fundamental properties of N‐DLC films are not only related to the nitrogen content in the film but also to the type of chemical bonds formed. Copyright © 2016 John Wiley & Sons, Ltd.     

ANTHEM: anatomically tailored hexagonal MRI

PURPOSE: This study aimed to investigate the use of anatomically tailored hexagonal sampling for scan-time and error reduction in MRI. MATERIALS AND METHODS: Anatomically tailored hexagonal MRI (ANTHEM), a method that combines hexagonal sampling with specific symmetry in anatomical geometry, is proposed. By using hexagonal sampling, aliasing artifacts are moved to regions where, due to the nature of the anatomy, aliasing is inconsequential. This can be used to either reduce scan time while maintaining spatial resolution or reduce residual errors in speedup techniques like UNFOLD and k-t BLAST/SENSE, which undersample k-space and unwrap fold-over artifacts during reconstruction. Computer simulations as well as phantom and volunteer studies were used to validate the theory. A simplified reconstruction algorithm for hexagonally sampled and subsampled k-space data was also used. RESULTS: A reduction in sampling density of 13.4% and 25% in each hexagonally sampled dimension was achieved for spherical and conical geometries without aliasing or reduction in spatial resolution. Optimal subsampling schemes that can be utilized by UNFOLD and k-t BLAST/SENSE were derived using hexagonal subsampling, which resulted in maximal, isotropic dispersal of the aliases. In combination with UNFOLD, ANTHEM was shown to move residual aliasing artifacts to the corners of the field of view, yielding reduced artifacts in CINE reconstructions. CONCLUSIONS: ANTHEM was successful in reducing acquisition time in conventional MRI and in reducing errors in UNFOLD imaging.