Facile synthesis of CoFe2O4-graphene oxide nanocomposite by high-gravity reactor for removal of Pb(II)

• The CoFe 2 O 4 -GO is rapidly and successfully prepared by hydrogen bond with IS-RPB; • The homogeneous micromixing contributes most to good dispersibility; • The CoFe 2 O 4 -GO shows higher reactivity for removal of Pb(Ⅱ); • The action to Pb(II) includes electrostatic adsorption, ion exchange and complexation. Heavy metals pose a serious threat to human health due to high toxicity and non-biodegradability, and the selection of adsorbent is crucial for the adsorption separation technology. In this paper, based on the problem of non-uniform micromixing in traditional stirred tank reactor (STIR) in the preparation of adsorbent, an impinging stream-rotating packed bed (IS-RPB) using the high gravity technology is proposed to quickly prepare CoFe 2 O 4 -graphene oxide nanocomposite (CoFe 2 O 4 -GO-RPB) in less than 1 min. Compared with STIR, IS-RPB has the advantages of good micromixing effect, short characteristic mixing time and easy formation of uniform supersaturated environment. The reactivity of CoFe 2 O 4 -GO-RPB was evaluated through the adsorption performance towards Pb(II), and the adsorption capacity was 459.8 mg·g -1 at the initial concentration of Pb(II) of 1000 mg·mL -1 and pH of 6. The adsorption behavior of CoFe 2 O 4 -GO over Pb(II) was preferably described by Langmuir isotherm model and Elovich model, and the analysis of XPS and FT-IR confirmed that Pb(II) was adsorbed by the action of electrostatic adsorption, ion exchange and complexation. Herein, a facile way of rapid preparation of CoFe 2 O 4 -GO with excellent reactivity is provided, and the preparation method of high-gravity co-precipitation will enrich the application of CoFe 2 O 4 -GO for hazardous heavy metal remediation from wastewater.