Design of ZIF(Co & Zn)@wool composite for efficient removal of pharmaceutical intermediate from wastewater

Removal of naphthols, as one of the most common pharmaceutical intermediates which released in the wastewater, is in the top priority for the time being. In the current study, zeolitic imidazole frameworks (ZIF-8, Zn & ZIF-67, Co) were directly prepared within the matrix of wool fabric to remove 2-naphthol from water. The ZIF@wool fabric composite was firstly prepared and then characterized by X-ray diffraction, infrared spectroscopy, electronic microscope and energy dispersive X-ray. The material contents within wool were measured to be 118.3-128.8 mg/g for ZIF and 31.5-33.0 mg/g for M⁺² (Zn & Co). The as-prepared composites were applied in the removal of 2-naphthol from water. Adsorption of 2-naphthol onto composites was followed to pseudo-first order kinetic model and the rate of adsorption was speeded up two times after incorporation of ZIF inside wool. Adsorption data were fully obeyed to Langmuir isotherm and the maximum adsorption capacity was extremely enlarged from 197.1 mg/g for wool to 371.2-391.1 mg/g for ZIF@wool composite, attributing to the increment in active binding sites. By regeneration for 4 cycles, the adsorption capacities of composites was reduced by only 8-9%. It is hypothesized that, the as-synthesized ZIF@wool fabric composite is a highly applicable adsorbent composite and could be safely applied in removing of 2-naphthol with the capability for the recycling.