Effects of Impeller Shape and Rotational Speed in a Stirred Tank on the Microplastic Capture Efficiency using Oil-Based Ferrofluid

Abstract

Microplastics in aquatic environments pose serious threats to ecosystems and human health due to their persistence and ability to adsorb toxic substances. This research focuses on developing an application method for oil-based ferrofluid to capture microplastics. Experiments were conducted in a stirred tank designed to enhance contact between microplastics and ferrofluid. Three impeller types were tested: a 4-blade EMI Rotofoil, a 4-blade propeller, and a 4-blade 45° pitched blade turbine, each operated at rotational speeds of 100, 150, 200, 250, 300, and 350 rpm. The efficiency of microplastic capture was evaluated by comparing the Number of microplastic particles in water samples before and after mixing, using microscopic analysis. Results showed that the 4-blade EMI Rotofoil at 350 rpm achieved the highest capture performance, while the 4-blade propeller at 100 rpm yielded the lowest. These findings highlight the potential of integrating ferrofluid with mechanical mixing in a stirred tank as an effective approach for microplastic removal from water systems.