Mechanism of arsenic removal from tannin‐‑germanium complex augmented by ultrasound

The volatilization of arsenic (As) pollutes the environment; thus, it must be removed before preparing a germanium (Ge) concentrate. This study examined the As removal from tannin‑germanium complex (TGC) augmented by ultrasound and revealed the reaction scheme in the As removal process. Parameters such as ultrasound power, sulfuric acid (H2SO4) concentration, particle size, liquid solid ratio, and reaction temperature were studied systematically. Experimental results showed that the maximum As removal efficiency augmented by ultrasound was 92.0% under the optimum purifying parameters of ultrasound power of 225 W, H2SO4 concentration of 20 g/L, particle sizes of 74–96 μm, liquid solid ratio of 7/1 mL/g, reaction temperature of 40 °C, and reaction time of 30 min. This removal efficiency is 11.2% higher than those of conventional methods under the same reaction conditions. The loss rate of Ge was only 4.9% under the optimal reaction conditions. Mechanism analysis showed that ultrasound can destroy the packaging structure of the raw materials and enhance the porosity, thus strengthen the reaction kinetics. [Display omitted] •A technique on purifying arsenic from tannin‑germanium complex augmented by ultrasound in H2SO4 system is proposed.•Compared with the conventional method, ultrasound increases the arsenic removal efficiency by 11.2%.•The TEM and BET analysis demonstrate the arsenic removal mechanism augmented by ultrasound.•Ultrasound enhances the porosity of raw materials, thus enhances the reaction kinetics.