Advanced Materials Research Vol. 487

Abstract: In (III) was quantitative adsorption by strong acid cationic exchange fiber (SACEF) in the medium of pH=2.50 sulphuric aicd. The statically saturated sorption capacity of SACEF was 153.8 mgg-1. 0.5 molL-1 H2SO4 could be used as an eluant. The elution efficiency was 99%. The SACEF could be regenerated and reused without apparent decrease of sorption capacity. The sorption rate constant was k287K=0.09379 gmg-1min-1, k300 K=0.1159 gmg-1min-1, k321 K=0.4046 gmg-1min-1 and k350 K=0.6678 gmg-1min-1, respectively. The apparent sorption activation energy of SACEF for In (III) was 28.28 kJmol-1.The sorption behavior of SACEF for In (III) obeyed the Freundlich isotherm. The enthalpy change was H=5.67 kJmol-1.

Abstract: A new method has been established for the pre-enrichment of trace heavy metals(lead(II), cadmium(II), chromium(VI) and nickel(II)) by magnetic iron oxide(core) / zirconium dioxide(shell) and determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) in water samples. The factors affecting the separation and pre-enrichment of analytes such as amounts of magnetic iron oxide / zirconium dioxide, elution time and interfering ions were studied. The detection limits of the method (3σ) were 13.5ng/mL, 1.01ng/mL, 2.94ng/mL and 3.31mg/L respectively for lead(II), cadmium(II), chromium(VI) and nickel(II). The results showed that this method was simple, accurate, and sensitive which could be applied for the pre-enrichment, separation and determination of trace heavy metals in all kinds of water samples.

Abstract: The block copolymer poly (ε-caprolactone)-b-poly (N-isopropyl acrylamide) (PCL-b-PNIPAM) is synthesized via the combination of ring-opening polymerization (ROP) and reversible addition-fragmentation chain transfer (RAFT). PCL-b-PNIPAM can self-assemble into the micelles taking PCL as the cores and PNIPAM as the shells. Add α-CD into the micelles, because the inclusion complexation of α-CD to PCL chains and phenols is stronger than that to PCL, to regulate the hydrophilic and hydrophobic features of PCL chain. So PCL-b-PNIPAM block copolymers have potential application in drug delivery and gene transfection.

Abstract: Abstract The multi-walled carbon nanotubes (MWNTs) are modified through acidification, followed by the graft of polycaprolactone. The supramolecular forces of α-cyclodextrins (α-CDs) and PCL are used to produce MWNTs hybrid materials with pseudopolyrotaxane structure. XRD, FTIR, TGA, DSC are used for the characterization of its product. The preparation of this hybrid material provides a new approach for modifying carbon nanotubes in supramolecular chemistry with the expectation of applying this hybrid materials to the field of biomedicine.

Abstract: Spherical sponge iron (SSI) with high activity and intension possesses potential characteristics to be utilized as wastewater treatment material, such as higher iron content, uniform particle size, higher compressive strength, etc. Observation on apparent morphology of exterior and microscopic morphology of SSI reduced by hydrogen under different temperature was carried on with SEM. When the reductive temperature was relatively lower than T4, the quantities of iron grain in exterior and interior of SSI increased with the increasing of temperature. When the temperature was elevated to T5, the particle size of iron grain was increased, and lots of macro-holes formed, especially in the interior section of SSI. When the temperature was T4, the SSI possesses more favorable ability to remove pollutant from wastewater. Moreover, the iron content in SSI was mostly reach to the summit under this temperature. In summarization, the reduction temperature should be controlled under T4 temperature if the sponge iron was utilized in wastewater treatment.

Abstract: Spherical sponge iron (SSI) with high activity and intension could be prepared through direct reduction by hydrogen. To optimize the reduction technology, thermodynamics of SSI reduction was investigated. Oxygen residue ratio in SSI declined with the reaction time despite of reaction temperature. It was concluded that SSI reduced by hydrogen appeared to be the first-order reaction, and the apparent reaction rate constant k was 0.289 h-1 to 3.819 h-1. Activity energy of SSI reduction was 22.19 kJ•mol-1 and 81.58 kJ•mol-1 corresponding to the lower temperature and higher temperature. When the temperature was lower than T4, the reaction rate was lower. Consequently, the optimized temperature should be controlled more than T5 to elevate the reduction rate.

Abstract: Spherical sponge iron (SSI) with high activity and intension could be prepared through direct reduction by hydrogen. To optimize the reduction technology of SSI and its removal ability for nitrate from wastewater, the influence of reduction temperature of SSI on nitrate removal was investigated. It was suggested that nitrate removal ability of SSI increased to the summit and then declined with the increasing of reduction temperature. When the reduction temperature of was T4, nitrate removal percentage reached to the maximum. When the original concentration of nitrate was only 5 mg-N/L, the additive quantity of SSI could prove plenty of zero-valent iron in a short time, and reduction temperature of SSI has little influence on nitrate removal. Nitrate removal by SSI appeared to be the pseudo-first-order reaction despite of reduction temperature. While nitrate original concentration was elevated to 50mg-N/L, the reaction order declined to the range of from 0.534 to 0.629 which was closed to 0.5, and the apparent reaction rate constant was 1.411 to 1.773 h-1.

Abstract: A novel copolymer of p-hydroxybenzoic acid and sulfanilic acid (pHBA-SAA copolymer) was synthesized by free radical copolymerization with horseradish peroxidase (HRP)/HB2BOB2B as initiator. The effects of the proportion of monomers, the amount of catalyst, reaction temperature and time on copolymer performance were investigated. The structure of the copolymer was characterized with FTIR, NMR and GPC. Shrinkage temperature (TBsB) of the leather tanned with the copolymer was 81.5°C. The thickness increment ratio of the retanned leather was 23.23% and meanwhile the retanned leather showed better softness and exceptionally good flexible. The results indicated that the graft copolymer has excellent retanning properties and particularly suited to be served as retannage substitute for chrome and resin retannages in making leather process.

Abstract: Polycarboxylate (PC) superplasticizer was synthesized by radical copolymerization using ammonium persulfate (APS) as initiator at 90 °C for 5 h. The effect of PC on the hydration process and microstructure of hardened cement at different hydration ages (4 h, 1 d and 7 d) was investigated. Hydration of cement paste results show that the nucleation and growth of hydration product of ettringite (Aft) was inhibited by PC at the early hydration ages, and the generation of the hydration products of calcium hydroxide (CH) and calcium carbonate (CaCO3) was promoted at late hydration ages. SEM result indicates that PC can make the structure of hardened cement more homogeneous and more density.

Abstract: The Cu thin films were prepared at room temperature by radio frequency magnetron sputtering on p-type Si (111) substrates. The surface morphology and interface reaction of Cu thin films were studied at different deposition condition by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the existence of the native silicon oxide layer suppresses the interdiffusion and interface reaction of Cu and Si. The formation of the copper-silicide phase is observed by XRD when the annealing temperature arrives at 450 °C.