Hydroxyapatite nanowires-based Janus micro-rods for selective separation of organics

The selective separation of organics is very important in environment management and experiment, and the development of functional materials for selective adsorption is still a challenge. In this study, using hydroxyapatite nanowires (HAnW) as an eco-friendly artificial inorganic carrier and manganese dioxide (MnO2) nanoparticles (MnO(2)NPs) as active ingredients, a rime-like HAnW-based Janus micro-rods (MnO(2)NPs@HAnW), which HAnW was coated by MnO(2)NPs, was synthesized by ion exchange and hydrothermal reactions. The obtained Janus micro-rods MnO(2)NPs@HAnW were applied to adsorb organic pollutants, including different antibiotics and dyes, such as tetracycline (TC), ciprofloxacin (CIP), amoxicillin (AMX), rhodamine B (RhB), methyl blue (MeB), basic fuchsin (BF), methylene blue (MB), crystal violet (CV), and malachite green (MG). It was found that MnO(2)NPs@HAnW could very efficiently and selectively adsorb organics. Taking TC and BF for studying adsorption kinetics and thermodynamics, it indicated that their adsorption process followed pseudo-second-order kinetics and Freundlich thermodynamic model. More importantly, the mixture of organics containing RhB could be efficiently separated by MnO(2)NPs@HAnW with the simple separation device, and it had good reusability. In summary, the eco-friendly MnO(2)NPs@HAnW is an excellent candidate for the sustainable treatment of dyes wastewater and efficient separation of the mixture of organics. And we developed a new strategy of heterogeneous combination for preparation of inorganic functional materials.