Removal of harmful alga, Chattonella marina, by recyclable natural magnetic sphalerite

Fish-killing harmful algal blooms (HABs) of Chattonella marina causes serious hazards and risks to fish farming and environment throughout the world. At present, it is necessary to explore cost-effective and recyclable materials for controlling C. marina blooms to reduce the cost and control the potential side effect to the environment. A novel earth-abundant natural magnetic sphalerite (NMS) for removing C. marina was systematically investigated, including the effect of NMS dosage, temperature, pH and salinity on algal removal efficiency. Algal cells could be rapidly removed by NMS (1-2g/L) through adsorption and physical interaction. The algal destruction process was enhanced under the following reaction conditions: temperature>25°C, salinity>30 ppt and pH value<7.5. The reusability of magnetic recycled NMS and effect of light irradiation on algal cell removal were also determined. NMS exhibited excellent stability after repeated algal cell removal, and the efficiency was further enhanced by light illumination. The current study suggested that using NMS to control C. marina blooms could be a novel promising strategy, which is cost-effective, stable, and easy for recycling.