Yeast-Based Magnetic Biocomposite for Efficient Sorption of Organic Pollutants

The study aimed to prepare a biocomposite containing Yarrowia lipolytica yeast cells with magnetic properties. The work proposes the use of this biocomposite as a sorbent for the removal of organic pollutants like methylene blue from liquids. The sorption process was conducted in a periodic process through which different parameters were analyzed such as initial concentration (50–250 mg/dm3), time of the process (0.167–24 h), and temperature (25–40 °C). To fit the experimental data to theoretical models, the Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich models were used. In addition, pseudo-first-rate, pseudo-second-rate order, Weber–Morris and Elovich kinetic models were evaluated. The highest fit was the Freundlich isotherm model (R2 = 0.9959 and ARE = 3.41%) and the pseudo-second-rate order model (R2 = 0.9989 and ARE = 1.14%). It has been shown that the process of removing methylene blue using a biocomposite is exothermic and its usefulness decreases with an increase in temperature (from 32.10 mg/g to 23.64 mg/g). To acquire information about the material characteristics, different instrumental methods were applied: FTIR, SEM-EDX, TGA, and VSM. This study provides new information on the possibility of using composites made of biochar, yeast, and magnetic particles in the process of removing dyes from an aqueous environment. The obtained biocomposite is effective in removing contaminants and is easily separated after the performed process.