Synthesis of a new reagent 4-(2'-thiazolylazo)-6-formyl-resorcinol and spectrophotometric determination of lead (II) in waste water

1009-1010Synthesis and characteristics of a new chromogenic reagent, 4-(2'-thiazolylazo )-6-formyl-resorcinol (TAFR) has been reported. The optimum conditions for spectrophotometric determination of lead (II) using TAFR is present. At pH 7.5-8.0, TAFR forms a 1: 1 red complex with lead (II) with molar absorptivity 1.62 x 104 I mol-1 cm-1 at 565 nm. Beer's law is obeyed in the range of 0-8 µg/25 ml Pb (II). The method has been applied for the direct determination of lead (II) in water samples

Synthesis of polyvinyl alcohol condensed 2,4-dihydroxy-5-antipyrinylazo phenylaldehyde and liquid-solid extraction of cadmium(II), copper(II), cobalt(II) and nickel(II)

1115-1118A polymeric chromogenic reagent, polyvinyl alcohol condensed 2,4-dihydroxy-5-antipyrinylazo phenylaldehyde (PV•DHAPA), has been synthesized for the first time by condensing 2,4-dihydroxy-5-antipyrinylazophenylaldehyde with polyvinyl alcohol. PV•DHAPA has been used to study the liquid-solid extraction behaviour of the complexes of cadmium(Il), copper(Il), cobalt(Il) and nickel(II) in water soluble polymer Tween 80- inorganic salt-water system under different experimental conditions

A Study of the Degradation of LEV by Transparent PVA/NCD-TiO₂ Nanocomposite Films with Enhanced Visible-Light Photocatalytic Activity

In recent years, antibiotics (such as levofloxacin (LEV)) have been detected widely in the environment. Semiconductor photocatalysis has been recognized as a promising technology for removing pollutants in the environment. In this work, nitrogen and carbon codoped titanium dioxide nano-catalyst (NCD-TiO2) was immobilized in polyvinyl alcohol (PVA) matrix to form PVA/NCD-TiO2 films through solution casting and thermal treatment, which exhibited good photocatalytic efficiency for LEV degradation. The results showed that about 42% LEV can be degraded after 2 h in the presence of PVA/NCD-TiO2 nanocomposite film (the weight ratio of NCD-TiO2 to PVA is 8% and thermal treatment is 120 °C) under visible light. Moreover, possible pathways of photocatalytic degradation of LEV according to the detected intermediates are proposed, which provide insight into the degradation mechanism of LEV by using PVA/NCD-TiO2 photocatalytic films. Finally, the synthesized PVA/NCD-TiO2 films exhibited excellent reusability and stability in photocatalysis. This work provides fundamental support for the design of a high-stability, excellent photocatalyst for practical application

Synthesis of a new chromogenic reagent, 1-(<em>p</em>-azophenyl)-3-(2-thiazol) triazene, and its application to determination of zinc(II)

466-468Synthesis and characterization of a new chromogenic reagent, l-(p-azophenyl)-3-(2-thiazol)triazene(APTT), are described. The reagent has been used for spectrophotometric determination of zinc(II) APTT forms a red colored complex with zinc(II) in alkaline m dium in the presence of Triton X-l00. The optimum conditions for the colour reaction have been descried. The molar absorptivity of the complex is 9.6 X 104 1.moI-1 cm-1 at 545 nm. Beer's law is obeyed over the range 0 - 2 µg/25ml Zn(lI). lnterference due to several ions has been studied. The recommended method has been applied to the determination of zinc(II) in aluminum alloys

A Study of the Degradation of LEV by Transparent PVA/NCD-TiO2 Nanocomposite Films with Enhanced Visible-Light Photocatalytic Activity

In recent years, antibiotics (such as levofloxacin (LEV)) have been detected widely in the environment. Semiconductor photocatalysis has been recognized as a promising technology for removing pollutants in the environment. In this work, nitrogen and carbon codoped titanium dioxide nano-catalyst (NCD-TiO2) was immobilized in polyvinyl alcohol (PVA) matrix to form PVA/NCD-TiO2 films through solution casting and thermal treatment, which exhibited good photocatalytic efficiency for LEV degradation. The results showed that about 42% LEV can be degraded after 2 h in the presence of PVA/NCD-TiO2 nanocomposite film (the weight ratio of NCD-TiO2 to PVA is 8% and thermal treatment is 120 &deg;C) under visible light. Moreover, possible pathways of photocatalytic degradation of LEV according to the detected intermediates are proposed, which provide insight into the degradation mechanism of LEV by using PVA/NCD-TiO2 photocatalytic films. Finally, the synthesized PVA/NCD-TiO2 films exhibited excellent reusability and stability in photocatalysis. This work provides fundamental support for the design of a high-stability, excellent photocatalyst for practical application

Study on the damping properties of magnetorheological elastomers based on cis-polybutadiene rubber

Magnetorheological elastomers (MREs) are composed of magnetizable particles (iron particles) and a soft rubber-like matrix. Their mechanical properties, including modulus and damping capability, can be controlled by an external magnetic field. The damping properties of MREs, which play an important role in applications, depend mainly on particle content. This paper aims to investigate MRE’s damping capabilities by studying two categories of cis-polybutadiene rubber-based MREs: isotropic and structured MREs. Both isotropic and structured MRE samples with various iron particle contents (60, 70, 80 and 85 wt%) were fabricated and their damping properties were measured by using a modified dynamic mechanical analyzer (DMA) and a universal testing machine. The results show that the loss factor in the glass transition region decreases with the increment of iron particle content. The loss factors of structured MREs are lower than those of isotropic MREs when the iron particle contents are the same. Furthermore, dynamic testing was conducted to study the effect of strain amplitude, frequency and magnetic field on the loss factor of MREs. In addition, the stress-softening experiments indicate that the ratio of remaining strain energy versus initial strain energy shows a decreasing trend with iron particle content and loading time

Investigating the confining compressibility of STF at high deformation rate

The split Hopkinson pressure bar (SHPB) was used to study the compressibility of shear thickening fluid (STF) at high deformation rate. In this study, a steel bulk was introduced into the SHPB system to confine and load the STF. A series of STFs with different particle types (SiO2 and PSt-EA) and volume fractions (63 vol.% and 65 vol.%) were tested and the results were compared. The reliability of the results was proved by repeating the tests and the force balance in suspension. The bulk modulus was used to evaluate the compressibility of STF, which indicated that the SiO2-based STF exhibited a larger compressibility than the PSt-EA-based STF. It was found that the bulk modulus increases with increasing of the strain rate and the volume fraction shows little effect on the bulk modulus. The structure-dependent mechanical property was analyzed and the loading effect of bulk modulus was considered to be originated from the interparticle clustering

Effect of maleic anhydride on the damping property of magnetorheological elastomers

In this study, maleic anhydride (MA) was selected as the compatibilizer to modify the interfaces of magnetorheological elastomers (MREs) for improving the damping property. Several samples of MREs with different contents of MA were prepared. The content of bound-rubber was measured by the extraction method. The microstructures were observed by using an environmental scanning electron microscope (SEM). The dynamic performances of these samples, including shear storage modulus, loss factor and MR effect were measured with a modified dynamic mechanical analyzer (DMA). The tensile strength was tested by using an electronic tensile machine. The experimental results indicate that both the content of bound-rubber and the compatibility between the magnetic particles and rubber matrix were enhanced with the increase of MA. The enhancement of the bond between the two phases resulted in different mechanical properties: the increase of shear storage modulus; the reduction of the loss factor; the stability improvement of the loss factor; the enhancement of the tensile strength; and the reduction of the MR effect