Magnesiation roasting kinetics exploration of vanadium slag toward minimization of tailing toxicity.

In order to minimize the toxicity of vanadium extraction tailings, the vanadium extraction efficiency should be as high as possible to minimize the residual V(V) content in tailings. In this work, the kinetics of the novel magnesiation roasting of vanadium slag, including the roasting mechanism and kinetic models, is explored to intensify the vanadium extraction. By combination of various characterizations, the microscopic mechanism of magnesiation roasting is revealed, which indicates the simultaneous occurrence of the salt-formation→oxidation routine (major) and the oxidation→salt-formation routine (minor). Macroscopic kinetic model studies show the magnesiation roasting of vanadium slag proceeds in two stages. In the initial 50 min, the roasting follows the Interface Controlled Reaction Model, during which the stable roasting temperature is essential to intensify the magnesiation. In the long-time range (50-90 min), the roasting follows the Ginstling-Brounstein Model, during which the acceleration of air blow rate is most favorable. With intensified roasting kinetics, the vanadium extraction efficiency is as high as 96.65%. This work has provided the guideline to intensify the magnesiation roasting of vanadium slag for vanadium extraction, which can not only minimize the tailing toxicity of vanadium extraction but also accelerate the industrial application of the novel magnesiation roasting technique.

Rapid Electrochemical Screening of Phenylketonuria Maker Depending on Dehydrogenase Attached to the Pt-Doped Reduced Graphene Oxide Nanocomposites.

Phenylketonuria (PKU) is a common disease associated with amino acid metabolism, and usually occurs in newborns. It can cause serious neurological diseases and even death. However, owing to inadequate-effective treatment, it can only be slowed by a low-phenylalanine (Phe) diet. In addition, PKU screening is essential for newborns in many countries. Therefore, rapid screening is crucial for preventing damage and meeting the large sample diagnosis demand. For confirmed patients, a convenient method to monitor their regular Phe levels is required. However, current clinical methods do not meet the rapid screening and convenient monitoring requirements. Herein, a rapid and facile electrochemical device based on platinum-doped reduced graphene oxide nanocomposites was developed to detect PKU biomarker-Phe. The results demonstrated that the developed electrode has great sensitivity, selectivity, and stability. The detection range was 0.0001 mM to 6 mM with a limit of detection of 0.01 µM. Therefore, this work offers a simple and rapid method for point-of-care PKU screening and daily monitoring.