Abstract:
Nano-Fe
3O
4 particles were deposited on the surface of tea waste (TW) by co-precipitation method to form tea waste@nano-Fe
3O
4 magnetic composited material, and then spherical tea waste@nano-Fe
3O
4/calcium algnate (TW@nano-Fe
3O
4/CA) magnetic beads were prepared by sol-gel approach. The magnetic composites were characterized by SEM, XPS, XRD, vibrating sample magnetometer (VSM) and universal testing machine. The adsorption properties and mechanism of methylene blue (MB) from aqueous solution onto the beads were studied. The results show that the TW@nano-Fe
3O
4/CA beads possess a good magnetic response, with the diamters ranges from 1.2 mm to 1.7 mm. The composited beads display a rough and folded surface morphology and porous inner structure. The diameters and magnetic response of the beads increase while the adsorption abilities of MB decrease with the increasing content of TW@nano-Fe
3O
4 in the beads. The adsorption kinetics followed is second order, and the adsorption isotherm data are well fitted to Langmuir model. The adsorption process of MB onto the beads is spontaneous, entropy decreased and exothermic process. The Langmuir maximum adsorption capacity of MB onto the beads with 80% mass fraction of TW@nano-Fe
3O
4 is found to be 272.5 mg·g
−1 at 303 K, which is increased by 86.7% than TW. The adsorbent shows satisfactory regeneration and recycling utiliziation performance.