Environment

[PY1-14] Suppression of the release of arsenic from arsenopyrite by carrier-microencapsulation using titanium-catechol complex

○Kagehiro Magaribuchi¹ (1. Hokkaido university)

Keywords:Arsenic, Arsenopyrite, Microencapsulation, Ti-catechol complex, Electrochemical studies

Arsenic (As), a toxic element, is commonly released from As–bearing sulfide minerals such as arsenopyrite (FeAsS) when they are oxidized due to exposure to atmospheric conditions. Carrier–microencapsulation (CME) has been proposed to fundamentally prevent the oxidation of sulfide minerals. In CME, metal(loid)–organic complex is used, which is oxidatively decomposed on the surface of sulfide minerals, resulting in the release of metal(loid) ion that is precipitated forming a protective layer on the surface. In this study, Ti⁴⁺-catechol complex was used as coating agent and applied in the CME treatment of arsenopyrite to suppress the release of As by forming Ti-oxyhydroxide coating. Moreover, electrochemical studies (e.g., cyclic voltammetry and chronoamperometry) were conducted to investigate the mechanism of Ti–catechol complex decomposition on arsenopyrite electrode as well as the passivation ability of protective layer formed by Ti–based CME treatment.