New applications of deep eutectic solvents for separation of quartz and magnetite

Enhancing the electrochemical sensitivity of hydroquinone using a hydrophobic deep eutectic solvent-based carbon paste electrode

The present study reports the synthesis and characterization of hydrophobic deep eutectic solvents (HDES) based on fatty acids and tetrabutylammonium bromide (TBAB) or 1-octanol using Fourier transform infrared spectroscopy, and the analysis of the physicochemical properties (viscosity, density, electrical conductivity, and water content) of these solvents. A carbon paste electrode modified with 6.0% (m/m) decanoic acid and TBAB-based HDES was characterized by cyclic voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy. The oxidation peak currents of the proposed electrode were enhanced by its high electrochemical activity, fast electron transfer rate, and high surface area, while a remarkable decrease was observed in the peak potential separation. The electrochemical determination of hydroquinone (H₂Q) was carried out using square-wave adsorptive anodic stripping voltammetry (SWAdASV). The electrode response was found to be linear in the H₂Q concentration range of 2.5 × 10^-6-3.0 × 10^-3 mol L^-1, with the limit of detection (LOD) of 7.7 × 10^-7 mol L^-1. The method was successfully applied for H₂Q determination in dermatological creams.

Effects of Al(III) Ions at Magnetite Flotation from Quartz by Dodecylamine Al(III)

The flotation separation of magnetite and quartz is a long-term challenge for the beneficiation industry. For high-quartz magnetite, conventional flotation shows poor separation effect, resulting in the waste of resources and low flotation efficiency. In this paper, dodecylamine acts as a collector and Al(III) ions in water act as a depressant to selectively separate magnetite and quartz at high alkalinity. The experimental results are analyzed by a micro-flotation experiment, solution chemical calculation, zeta potential, contact angle measurement, and Fourier transform infrared spectroscopy (FTIR). The results of micro-flotation experiments showed that Al(III) ions in water inhibited magnetite more strongly than quartz. The calculation results of solution stoichiometry and zeta potential showed that the phase formed by Al(III) ions on the surface of magnetite and quartz are mainly Al(OH)3(s), which covers the surface of magnetite and quartz, The contact angle measurement results showed that with the addition of Al(III) ions, the contact angle of magnetite varies significantly than that of quartz, and the floatability of magnetite is lower than that of quartz. The FT-IR results further indicated that the addition of Al(III) ions could hinder the adsorption of dodecylamine on the magnetite surface. Meanwhile, the addition of Al(III) ions has no obvious effect on the adsorption of dodecylamine on the quartz surface.