Novel morphology-controlled three-dimensional flower-like magnetic CoFe2O4/CoFe-LDHs microsphere for high efficient removal of Orange II

Abstract

• Novel flower-like magnetic CoFe 2 O 4 /CoFe-LDHs microspheres have been fabricated. • The existence of SO 4 2- and reaction time can influence the formation of structure of composites. • CoFe 2 O 4 /CoFe-LDHs exhibit remarkable adsorption performance of 1940 mg g −1 towards Orange II . • Adsorption mechanism includes anion exchange, hydrogen bonding, coordination and surface adsorption. Novel three-dimensional flower-like magnetic CoFe 2 O 4 /CoFe-LDHs microspheres were fabricated via a facile one-step hydrothermal method without any other operation. CoFe 2 O 4 /CoFe-LDHs microspheres could possess strong magnetic performance directly without calcination procedure. By controlling reaction time and anion type of raw materials, three-dimensional flower-like structure microspheres could be obtained. Then the structural and surface properties of the prepared CoFe 2 O 4 /CoFe-LDHs were investigated by a comprehensive set of characterization techniques closely. Besides, as-prepared composites exhibited remarkable adsorption performance towards Orange II and the maximum adsorption capacity could be high to 1940 mg·g −1 , several times higher than the adsorption capacity of other adsorbents reported and amorphous CoFe 2 O 4 /CoFe-LDHs prepared in this work, proving three dimensional porous structures could contribute to higher adsorption performance. Moreover, batch experiments were conducted systematically to evaluate the effects of the initial concentration of Orange II, pH, temperature and time on the adsorption behavior of Orange II on CoFe 2 O 4 /CoFe-LDHs. The adsorption kinetics and isotherm studies indicated adsorption progress obeyed the pseudo-second-order and Langmuir model respectively. Formation mechanism and adsorption mechanism were both studied deeply. What’s more, adsorbents and sample solution could be separated from each other quickly by an external magnet. These results suggested CoFe 2 O 4 /CoFe-LDHs composite was an effective and promising adsorbent for the removal of dye pollutants.