Ferrihydrite and green rust (GR) have been identified as promising removing agents for chromate. However, while ferrihydrite efficiency is the still too low for practical applications, it is not known whether GR is stable in real wastewater systems. In this work, we investigated the removal of chromate from a real tannery wastewater by using sulfate-GR and ferrihydrite. We studied the effect of pH and Cr/Fe molar ratios on removal performances and elucidated the removal mechanism by XRD analysis. We performed removal experiments from simple chromate-bearing solutions under non-oxidizing Ar atmosphere, and from complex solution under open air atmosphere.

Several metallic materials have been developed for many purposes by alloying and controlling microstructure. From the viewpoint of materials recycling, several properties should be controlled by the latter in simple alloys. The purpose of this work was to establish a method for evaluating microstructure in metallic materials by a precise measurement of electrical resistivity. Electrical resistivities at 77 K and 300 K were measured by a direct current four-point method in commercially purity titanium plates after tensile deformations. The resistivities basically increased by the deformations. The Matthiessen’s plot shows good linearity. Microstructure might be potentially evaluated by this method.