Investigation on viscosity and non-isothermal crystallization behavior of P-bearing steelmaking slags with varying TiO2 content

The viscous flow and crystallization behavior of CaO-SiO2-MgO-Al2O3-FetO-P2O5-TiO2 steelmaking slags have been investigated over a wide range of temperatures under Ar (High purity, >99.999 pct) atmosphere, and the relationship between viscosity and structure was determined. The results indicated that the viscosity of the slags slightly decreased with increasing TiO2 content. The constructed nonisothermal continuous cooling transformation (CCT) diagrams revealed that the addition of TiO2 lowered the crystallization temperature. This can mainly be ascribed to that addition of TiO2 promotes the formation of [TiO6]-octahedra units and, consequently, the formation of MgFe2O4-Mg2TiO4 solid solution. Moreover, the decreasing viscosity has a significant effect on enhancing the diffusion of ion units, such as Ca2+ and [TiO4]-tetrahedra, from bulk melts to the crystal–melt interface. The crystallization of CaTiO3 and CaSiTiO5 was consequently accelerated, which can improve the phosphorus content in P-enriched phase (n2CaO·SiO2-3CaO·P2O5). Finally, the nonisothermal crystallization kinetics was characterized and the activation energy for the primary crystal growth was derived such that the activation energy increases from −265.93 to −185.41 KJ·mol−1 with the addition of TiO2 content, suggesting that TiO2 lowered the tendency for the slags to crystallize

Metal adsorption behavior of 2,4-dinitrophenyl hydrazine modified polyacrylonitrile nanofibers

Electrospun polyacrylonitrile nanofiber mats (es-PAN nanofiber mats) were surface modified by 2,4-dinitrophenyl-hydrazine (2,4-DNPH) to yield the metal ion adsorption material (es-PAN-DNPH nanofiber mats) and were investigated their adsorption behaviors. Functional modification of the es-PAN nanofiber mats and conventional polyacrylonitrile fibers (c-PAN fibers) were prepared by using 4% (w/v) of 2,4-DNPH in 1,2-ethandiol at 110°C for 6 h to obtained c-PAN-DNPH fibers. The average diameter of the es-PAN-DNPH nanofiber mats was 0.25 µm, which was comparatively smaller than the es-PAN precursor. Their functional groups were confirmed by Fourier transform infrared spectroscopy (FT-IR) and their adsorption behaviors to trace Ag(I), Bi(III), Ga(III), and In(III) from aqueous solutions and were investigated by the induced couple plasma technique. The FT-IR spectra showed the existence of NN=C–NHNH–, O=C–NHNH–, and –NO2 functional groups for metal complexes. The adsorption capacities of the obtained es-PAN-DNPH were 7.14 to 36.36% higher than those of c-PAN-DNPH fibers. All adsorption plots onto es-PAN-DNPH nanofiber mats and c-PANDNPH fibers followed the Langmuir isotherm and indicated monolayer adsorption characteristics

Antimicrobial efficacy of a novel silver hydrogel dressing compared to two common silver burn wound dressings: Acticoat™ and PolyMem Silver ®

A novel burn wound hydrogel dressing has been previously developed which is composed of 2-acrylamido-2-methylpropane sulfonic acid sodium salt with silver nanoparticles. This study compared the antimicrobial efficacy of this novel dressing to two commercially available silver dressings; Acticoat™ and PolyMem Silver®. Three different antimicrobial tests were used: disc diffusion, broth culture, and the Live/Dead® Baclight™ bacterial viability assay. Burn wound pathogens (P. aeruginosa, MSSA, A. baumannii and C. albicans) and antibiotic resistant strains (MRSA and VRE) were tested. All three antimicrobial tests indicated that Acticoat™ was the most effective antimicrobial agent, with inhibition zone lengths of 13.9-18.4 mm. It reduced the microbial inocula below the limit of detection (10 2 CFU/ml) and reduced viability by 99% within 4 h. PolyMem Silver® had no zone of inhibition for most tested micro-organisms, and it also showed poor antimicrobial activity in the broth culture and Live/Dead® Baclight™ assays. Alarmingly, it appeared to promote the growth of VRE. The silver hydrogel reduced most of the tested microbial inocula below the detection limit and decreased bacterial viability by 94-99% after 24 h exposure. These results support the possibility of using this novel silver hydrogel as a burn wound dressing in the future