Advanced Materials Research Vols. 875-877

Abstract: The removal of pesticides (quintozene, α-BHC, Aldrin and pp′-DDT) by phenyltrimethylammonium bromide (PTMAB) modified montmorillonites(PTMAB-MMT) was investigated. The results showed that these four kinds of pestcides have high affinity with PTMAB-MMT. The composites were characterized by FTIR and XRD. Further, the removal experiments of pesticides in ginseng extracts were carried out. The Ginsenosides were analyzed by high performance liquid chromatography/mass spectrometry showed that the loss of Ginsenosides was less than 4%. It can be concluded that the PTMAB-MMT is a promising material in pesticide pollution treatment

Abstract: Nano-Cu-vermiculite composite with high distribution coefficients and adsorption capacity towards iodine ion in phosphoric acid systemwere prepared. This material was prepared by loading organic and copper salts with an ion exchange method on vermiculite substrate. Adsorption kinetic and role of phosphoric acid was discussed. Adsorption kinetic experiments indicated that more than 90% of the iodine was absorbed by the composite within the first 30 min and the adsorption kinetic fitted the pseudo-second-order model well. Phosphoric acid has little effect on the extraction, which provides a theoretical basis for the extraction of iodine in the wet-process phosphoric acid. Various characterization methods including SEM, and TG/DTA were utilized for the evaluation of nano-Cu-vermiculite composite. The interlayer spacing increased after CTAB and copper were inserted in vermiculite, and the size of sphere nanocopper in the range of 50-100 nm distribute on the surface and in the interlayer. Therefore the nano-Cu-vermiculite adsorbent has a promising application in iodine extraction from the wet-process phosphoric acid.

Abstract: We report the exchange bias properties in the bulk Ni₄₅Co₅Mn₃₈Sn₁₂ quaternary Heusler alloy. The ferromagnetic (FM) –antiferromagnetic (AFM) interactions get reinforced after the Co substitution for Ni in the Ni-Mn-Sn alloy, which increase the exchange bias field (HE). A maximum shift in hysteresis loops of 306 Oe was observed in the 10 kOe field cooled sample. The origin of this large exchange bias field has been discussed. Magnetic hysteresis loop obtained in the zero field cooled (ZFC) mode shows double-shifted loop, and the reason of this phenomenon has been explained in detail.

Abstract: The influence of substitution Co for Ni on the phase structure and electrochemical properties of La4MgNi19 phase composition alloys have been investigated systematically.The structure analyses show that the alloys are mainly composed of multiphase,such as CaCu5 phase ,Pr5Co19 phase and Ce5Co19 phase.The electrochemical measurement showed that alloy electrodes could be activated in 2-3 cycles, with increasing of x value, the maximum discharge capacity gradually increased from 345.7 mA·h/g (x = 0.0) to 382.8 mA·h/g (x = 2.0), cyclic stability increased a little ,but high-rate dischargeability (HRD) decreased somewhat. It is found that the HRD was mainly controlled by the electrocatalytic activity on the alloy electrode surface,and the improvement of cyclic stability was due to the increase of CaCu5 phase and Ce5Co19 phase . CaCu5 phase increased with increasing Co content. Ce5Co19 phase has a small corrosion rate in the electrochemical cycle.

Abstract: The phase structure and electrochemical properties of La4MgNi17M2(M=Ni,Co,Mn) alloys were investigated in detail. The XRD analysis revealed that the main phases in the alloys are LaNi5 and La4MgNi19 phases (Ce5Co19+Pr5Co19 structure). When the Ni element in the alloy was substituted by Mn or Co, the abundant of La4MgNi19 phase increased, and especially in the La4MgNi17Mn2 alloy, that increased to 70.7%. The electrochemical measurement showed that the activation of La4MgNi17M2(M=Ni,Co,Mn) alloy electrodes were improved, and it only needed 1-2 cycles.what’s more, with the elements substitution for Ni ,the maximum discharge capacity gradually increased to 386.10 mA·h/g (Co) and 375.18 mA·h/g (Mn), but high-rate dischargeability (HRD) decreased somewhat (Co, HRD900=86.2%). It is found that the HRD was mainly controlled by the electrocatalytic activity on the alloy electrode surface, and the decline of cyclic stability was due to the appearance of A5B19 type phase with larger hydrogen storage capacity, which lead to bigger volume expansion or intercrystalline stress, then easier pulverization during charging/discharging. In addition, the cyclic stability (S100) was improved with Co substitution, and worsened with Mn substitution, because Mn element was easily corroded and Co improved the ability of Corrosion resistance.

Abstract: The aim of this research article is to discuss the mechanical performance of WS2-Epoxy composite with varying % vol.of WS2. Studies were carried out with epoxy (ARL136+ AH-126) composite system consisting of Tungsten disulphide (WS2) as filler. The samples tested consist of bisphenol-A based epoxy liquid resin and Lapox AH-126 hardener with varying tungsten disulphide (WS₂). Appropriately cured samples gave excellent mechanical properties. Results showed that the tensile strength of the composites increased with increase in filler content for the range of filler contents (2.5-4 % vol.) and decreased with increase in the filler contents 5% vol. onwards. The result indicated that at 3% of filler concentration the tensile strength obtained is good with moderate density and hardness.

Abstract: To improve the selectivity of light olefins, Phosphorous modified ZSM-5 zeolites catalysts with different phosphorous content were prepared by impregnation and were used in the conversion of methanol to olefins. The properties of acidity and microporous structure of the phosphorous modified ZSM-5 zeolites were investigated by XRD, N₂-adsorption and desorption, and NH₃-TPD. The highest propylene yield (50.82%) was observed over the H-ZSM-5 modified with the phosphorus content at 9% (weight percent). The selectivity of propylene depended strongly on the phosphorus content in the zeolites; The enhancement of propylene selectivity with increasing phosphorous content was attributed to reduction of strong acid sites on the H-ZSM-5. Modification of the ZSM-5 zeolites with phosphorous also changes the microporous structure.

Abstract: A nitrogen-doped titania nanoparticle film on an ITO substrate was successfully obtained by gas phase method. Such a nitrogen-doped titania nanoparticle film on an ITO substrate shows efficient at the responsivity under the visible light exposure. TiO₂ photo-anode with N-doped was fabricated using nanocrystalline pastes and their N719-sensitization led to a short-circuit photocurrent density of 3.95 mA/cm² and a solar energy conversion efficiency of 1.72% under air-mass 1.5 global and illumination with the intensity of 100 mW/cm² (AM 1.5G, 100 mW/cm²).

Abstract: Highly dispersed supported gold catalysts have been prepared by solution reduction method using L-lysine as protection agents, and their catalytic activity was evaluated by the liquid phase catalytic oxidation reaction of glucose to gluconic acid. The results suggested that the Au/ZrO₂ catalyst, exhibited high activity for the selective oxidation of glucose. At the reaction temperature of 323K, reaction time of 1h, with the NaCO₃-NaHCO₃ as buffer solution, the yield of gluconic acid was 100%.

Abstract: The composition of the microemulsion plays a key role in modulating the formation of nanoparticles of inorganic materials. In order to understand the modulating mechanism, the composition of the middle phase microemulsion formed by Sodium Dodecyl Sulfonate/ 1-Alcohol/ n-Alkane/ Water quaternary system was studied by δ-γ phase diagram. A series of phase inversions O/W (2) → B.C.(3) → W/O( ) were observed with the increase in 1-alcohol concentration. Some physicochemical parameters, such as the coordinates of the start (βΒ, εB) and end points (βE, εE) of the middle-phase microemulsion, the mass fractions of AS (CS) and 1-alcohol (CA) in the total system, and the solubilities of AS (SO) and 1-alcohol (AO) in oil phase, were calculated. The influences of n-alkanes, 1-alcohol and concentration of NaCl solution on the composition of middle phase microemulsion were significantly.