Preparation of a magnetic Cu2+/organic zeolite 5A composite antibacterial agent and its application in the treatment of wastewaters containing bacteria

Abstract

CoFe₂O₄ magnetic fluid (CMF) and zeolite 5A (Z₅) were prepared by reflux and hydrothermal synthesis, respectively. Then Z₅ was combined with different amounts of CMF to produce a magnetic zeolite 5A (MZ₅). MZ₅ was used to produce the magnetic copper type zeolite 5A (MCZ₅) by an ion-exchange method. Finally, an organic antibacterial agent was joined into the MCZ₅ to produce a magnetic Cu²⁺/organic zeolite 5A composite antibacterial agent (MCOZ₅). The surface microtopography, particle size and magnetic properties of all samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM). The magnetic separation recovery of the MCZ₅ and MCOZ₅ were determined using magnetic separation recovery equipment. The results indicated that the saturation magnetization (Ms), remanence magnetization (Mr) and coercive force (Hci) of the MZ₅ containing 25% CoFe₂O₄ were 17.842 (A m² kg⁻¹), 4.8257 (A m² kg⁻¹), and 427.73 G, respectively. The antibacterial ratios of the MCOZ₅ to Staphylococcus aureus and Escherichia coli were 99.02% and 99.17%, respectively, when the adsorbed Cu²⁺ reached 51.29 mg g⁻¹ and the added organic antibacterial agent was up to 3.5%. The antibacterial agent can be recovered from a suspended solution by magnetic separation technology after dealing with wastewater containing bacteria. The magnetic separation recovery of the MCOZ₅ was 96.14% when 25% of CoFe₂O₄ was loaded.