Preparation and performance of magnetic diatomite

In view of the low adsorption capacity and difficult solid-liquid separation of existing diatomites, two kinds of magnetic diatomite, viz, I and II, were prepared by a common precipitation method. Scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area analysis, and X-ray diffraction (XRD) were used to characterize the magnetic diatomites, and their magnetic hysteresis loops were evaluated. The adsorption of nitrobenzene by the two samples was investigated by changing the pH, adsorbent amount, and adsorption time, and the performance during solid-liquid separation after saturated adsorption was also discussed. The results showed that the saturated magnetizations of the two samples were 26.28 and 4.8 emu/g, while the specific surface areas were 39.242 and 60.588 m²/g, which were 1.3 and 2 times that of the raw diatomite. The nitrobenzene removal rates reached 74.95% and 95.2%, which were 1.8 and 2.3 times that of the raw diatomite. The magnetic samples could be separated quickly under magnetic fields, and the concentration SS were 8.6 and 9.8 mg/L in two modified sample solutions after separation.