Advanced Materials Research Vols. 550-553

Abstract: The eznyme biosensor(EB) as a sort of biosensors are widely used analyse target substances from samples of medicine, environment and food processing in recent years. During the EB preparation, effective immobilization of enzyme is a key step related with the activity of enzyme and the lifetime of EB. In current research, a method to determine nonylphenol(NP) contents in the water samlples has been developed on the base of laccases cetyltrimethyl ammonium bromide -carbon paste electrode. The experimental results showed that the EB developed in this optimized conditions, its minimum detectable limit could reach 0.2µg／L, and the recovery was in the range from 91% to 109% at the concentrations form 3.0×10^-4 mol.L^-1 to 5.0×10^-6 mol.L^-1. The sensor is perfect which is convenient, effective, and cheap and really can be used practice.

Abstract: Electrochemical mass transfer in turbulent flows and binary electrolytes is investigated. The primary objective is to provide information about mass transfer in the near-wall region between a solid boundary and a turbulent fluid flow at different Schmidt numbers. Based on the computational fluid dynamics and electrochemistry theories, a model for turbulent electrodes channel flow is established. The turbulent mass transfer in electrolytic processes has been predicted by the direct numerical simulation method under limiting current and galvanostatic conditions, we investigate mean concentration and the structure of the concentration fluctuating filed for different Schmidt numbers from 0.1 to 100 .The effect of different concentration boundary conditions at the electrodes on the near-wall turbulence statistics is also discussed.

Abstract: A polyurethane resin catalyst with the cross-linking silver (Ag) ion is successfully synthesized in this study, and its use as a catalyst in electroless copper deposition is also analyzed. FT-IR, SEM, EDX and electrochemical open circuit potential-time (OCP-t) technique are used to analyze the structure of the catalyst, the process of catalyzing copper deposition and induced rate of the electroless copper deposition. We also demonstrate that the polyurethane resin catalyst containing silver ion can be screen printed onto the PET substrate, then, a Cu pattern is successfully fabricated on the PET after electroless copper plating.

Abstract: Tin dioxide nanoparticles were directly one-step recovered from electronic wastes using ultrasonic-assisted electrochemical method. The products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), which indicated that the average size of tetragonal SnO₂ is 100 nm. The experiment parameters, such as the concentration of electrolyte, electrolysis current, reaction time and electrode distance, were also discussed. The proposed method is high energy efficient, non-toxic and environment-friendly, and suitable for the recovering of electronic wastes under the controllable reaction condition at room temperature.

Abstract: In order to improve the performance of PbO₂ electrode, A kind of surface active agent – AEO-7 was added into nitric acid bath and modified PbO₂ electrode was prepared on stainless steel substrate by anodic oxidation. The modified variations on surface morphology of the electrodes were examined by Scanning Electron Microscopy(SEM); The polarization curves, Tafel curves and Cyclic voltammograms of modified and unmodified PbO₂ electrodes were compared in Crystal violet solution; The electrocatalytic activities were inspected by electrocatalytic degradation of crystal violet. It was found that the modified electrode showed higher oxygen evolution potential, better corrosion resistance, and more excellent electrocatalytic activity than the unmodified electrode.

Abstract: TiO₂-ZrO₂ fine binary oxide was firstly prepared by mechanochemical milling process to be homogeneous binary oxide powder. TiO₂-ZrO₂ paste was deposited onto microscopic glass slide by rolling. It was immersed in the Rose solution at different pH levels and annealed at 100°C for 2h. Carbon catalyst obtained from soot and HCl was coated onto another glass slide and it was used as counter electrode. Two glass slides were offset and two binder clips were used to hold the electrodes together. Photovoltaic properties of TiO₂-ZrO₂ cells were measured at different pH levels and it was expected to utilize the dye sensitized solar cells application. The highest efficiency (0.23%) of the dye sensitize solar cell was found to be rose extract at pH level 4.1. The cell exhibited the potential to be a low-cost photovoltaic option.

Abstract: This paper reports the fabrication of AAO tubular membrane using 99.35% and 99.56% pure Al and their potential application for hemodialysis. Here we discussed the effect of impurity on membrane structure. We found that the self organized structure of AAO nanochannels minimizes impurity defects in membrane. If micro size impurity blocks the generation of nanochannels then the neighboring nanochannels bend and make branches to fulfill that gap. We observed that if impurity size is less than the AAO membrane thickness then it does not produce any micro size hole. In low grade Al the periodic hexagonal order was disturbed however there was no big difference in pore diameter. It was observed that such type of membrane do not have any leakage and it can be used for fluid filtration. The fabricated tubular membrane was used for hemodialysis successfully. The hemodialysis results show that AAO tubular membrane can be used for both diffusive and convective filtration

Abstract: When thickness of a membrane reduces its mechanical properties go down but thinner the membrane better the performance of the membrane in terms of filtration. In this research we fabricated a fluid filtration system with a very thin anodic aluminum oxide (AAO) membrane. The system consists of microchannels at one side of membrane while other side is flat. For both sides inlet and outlet are given. The system can facilitate two types of fluid to flow at two sides of membrane for filtration. The membrane thickness achieved was 4 μm. The average pore diameter was 50 nm. The nanopores inside the membrane are highly straight and perpendicular to the surface. The fabricated channel and wall width was 200 µm and 100 µm successively. The pillars in between microchannels hold the membrane which is termed as partial freestanding alumina (PFA) and thereby retain desired mechanical properties of the membrane. The system was tested for diffusion between DI water and salted water. The DI water was flowed in channels and salted water on other side of membrane. The pH value of DI water changed after flow. Due to channel walls, AAO membrane fabricated in this system can tolerate more pressure which leads it to be used for convective flow by applying higher pressure gradient.

Abstract: This study is focus on the separations of ammonium lactate from lactic salts by Electrodialysis. Effects of work voltage, ammonium lactate initial concentration in the demineralization chamber on ammonium lactate separation in an electrodialyzer with heterogeneous membranes have been studied during the process of electrodialysis. Experimental results show that the optimum conditions of the process of ammonium lactate concentration by electrodialysis are the following: 18V work voltage, 40g/L ammonium lactate initial concentration.

Abstract: Due to the high stability and potential characteristics to the economical and environmental, the Li₃V₂(PO₄)₃ increased the global concern on the polyanionic materials. In this work, we using Li₂CO₃, V₂O₅, NH4H2PO4 and PEG as raw materials to compared the flow phase reaction and high temperature solid state synthesis of lithium vanadium phosphate composites. The results of this study can be considered in making decision which conditions of achieved precipitation of carbon source can be efficiently applied in a real Electrochemical performance manufactory. The obtained results indicated that using Glucose as carbon source, and calcined at 800 °C, 0.1C rate current conditions, high temperature solid state sintering of lithium vanadium phosphate composites for the first time following a discharge capacity of 119.31mAh/g, which has a good reusability performance.