Graphene sheets doped with nitrogen were produced by the reduction-expansion (RES) method utilizing graphite oxide (GO) and urea as precursor materials. The simultaneous graphene generation and nitrogen insertion reactions are based on the fact that urea decomposes upon heating to release reducing gases. The volatile byproducts perform two primary functions: (i) promoting the reduction of the GO and (ii) providing the nitrogen to be inserted in situ as the graphene structure is created. Samples with diverse urea/GO mass ratios were treated at 800 °C in inert atmosphere to generate graphene with diverse microstructural characteristics and levels of nitrogen doping. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to study the microstructural features of the products. The effects of doping on the samples structure and surface area were studied by X-ray diffraction (XRD), Raman Spectroscopy, and Brunauer Emmet Teller (BET). The GO and urea decomposition-reduction process as well as nitrogen-doped graphene stability were studied by thermogravimetric analysis (TGA) coupled with mass spectroscopy (MS) analysis of the evolved gases. Results show that the proposed method offers a high level of control over the amount of nitrogen inserted in the graphene and may be used alternatively to control its surface area. To demonstrate the practical relevance of these findings, as-produced samples were used as electrodes in supercapacitor and battery devices and compared with conventional, thermally exfoliated graphene.

Clinical laboratory wastewaters are of important environmental concern due to the highly complex chemical reagents and dyes used to identify various pathologies, which are difficult to degrade by conventional treatment methods. The present research aimed to assess the effects of ilmenite use in the discoloration process of clinical laboratory wastewater. The wastewater originates from a Gram staining process used to identify pathogenic microorganisms present in biological samples. The active ingredient is crystal violet, a triphenylmethane dye derivative, highly toxic and non-biodegradable that causes a shiny purple color in the wastewater. The ilmenite was characterized by X-ray Fluorescence, X-ray Diffraction, Scanning Electron Microscopy, energy-dispersive spectroscopy and Nitrogen adsorption isotherm, while the discoloration process of the wastewater was measured by UV–Vis spectrophotometry and pH change trough the reaction time, evaluating different ilmenite loads, particle size and stability under light sources with different energies. Chemical oxygen demand analysis confirmed that acid formation and discoloration were associated with organic substance mineralization. Type C ultraviolet light and 0.7 g/L load were identified as the best operating conditions for the discoloration process. It was possible to establish that ilmenite is stable after four uses in the discoloration process, obtaining, in all cases, discoloration percentages higher than 90% after 3 h of irradiation.

This work demonstrates that a version of the Reduction Expansion Synthesis (RES) process, Cr-RES, can create a micron scale Cr coating on an iron wire. The process involves three steps. I. A paste consisting of a physical mix of urea, chrome nitrate or chrome oxide, and water is prepared. II. An iron wire is coated by dipping. III. The coated, and dried, wire is heated to ~800 °C for 10 min in a tube furnace under a slow flow of nitrogen gas. The processed wires were then polished and characterized, primarily with scanning electron microscopy (SEM). SEM indicates the chrome layer is uneven, but only on the scale of a fraction of a micron. The evidence of porosity is ambiguous. Elemental mapping using SEM electron microprobe that confirmed the process led to the formation of a chrome metal layer, with no evidence of alloy formation. Additionally, it was found that thickness of the final Cr layer correlated with the thickness of the precursor layer that was applied prior to the heating step. Potentially, this technique could replace electrolytic processing, a process that generates carcinogenic hexavalent chrome, but further study and development is needed.

Carbon-based nanocomposites featuring enhanced electrical properties have seen increased adoption in applications involving electromagnetic interference shielding and electrostatic dissipation. As the commercialization of these materials grows, a thorough understanding of how thermal activation affects the rheology and electrical performance of CNT–epoxy blends can inform quality decisions throughout the production process. The aim of this work was the identification of the effects that thermal activation has on the electrical and rheological properties of uncured epoxy mixtures and how those may be tied to the resulting cured composites. Herein, three distinct CNT-loaded composite mixtures were characterized for changes in electrical resistivity and viscosity resulting from varying activation times. Electrical conductivity decreased as activation time increased. Uncured mixture viscosity exhibited a strong dependence on CNT loading and applied strain, with activation time being found to significantly reduce the viscosity of the uncured mixture and surface profile of cured composite films. In all cases, cured composites featured improved electrical conductivity over the uncured mixtures. Factors contributing to the observed behavior are discussed. Raman analysis, optical microscopy of CNT networks, and data from silica bead mixing and dispersion studies are presented to contextualize the results.

The mechanisms by which nanomaterials interact with biological systems is not well understood and although the benefits of some nanomaterials are evident, some offset effects on health and the environment may occur; however, scientific information is scarce. This document gives a brief description of the effects of nanomaterials on health and the current tendencies in developing the pertinent regulations. La forma como los materiales nanométricos interactúan con sistemas biológicos es poco conocida, y aunque los beneficios de algunos nanomateriales son evidentes también existe la posibilidad de que algunos puedan ser nocivos para la salud y el medio ambiente; sin embargo, la información científica sobre los efectos de los nanomateriales en estos ámbitos es escasa. Este documento hace una breve descripción de los efectos en la salud de los nanomateriales y los desarrollos legislativos concernientes a su regulación.