抄録
Recently, scorodite has been studied as a promising storage material for arsenic. Scorodite is synthesized through a solution method using pentavalent arsenic [As(V)] and divalent iron [Fe(II)] in an acidic solution. The particle size of scorodite can vary but larger ones are preferred because the low surface-to-volume ratio makes it difficult to dissolve in an acidic solution. In the solution method, large scorodite particles (>10 μm) are synthesized at high temperature (>90℃) with a long reaction time (7 h). The high reaction temperature is an important factor in synthesizing scorodite with large particle sizes. In this study, we investigated the effect of reaction temperature (30℃) during ultrasound irradiation on the size and morphology of synthesized scorodite particles. When the scorodite is synthesized using stirrer with H_2O_2, ORP and yield showed higher values and it means that oxidation of Fe(II) was promoted in the reaction solution. However, we confirmed crystallization of scorodite when using ultrasound alone. The reason behind this may be due to the oxidation promotion by cavitation during ultrasound irradiation. We consider that oxidation promotion led to synthesize the scorodite with a short reaction time. To the best of our knowledge, this is the first report on the synthesis of scorodite at low temperature (30℃) using ultrasound irradiation.