Preparation of polydopamine nanofibers mat as a recyclable and efficient adsorbent for simultaneous adsorption of multiple tetracyclines in water

Particle usage form or rigorous and complex preparation procedures limits the practical applications of the most adsorbents for tetracyclines (TCs). Herein, novel polydopamine nanofibers mat (PDA-NFsM) has been simply synthesized by a facile one-step polymerization method. The pH effect, adsorption kinetics, adsorption isotherms, as well as the competitive adsorption behaviors of the three kinds of tetracyclines (TCs), including chlortetracycline hydrochloride (CTC), oxytetracycline (OTC) and tetracycline hydrochloride (TC) on PDA-NFsM has been systematically studied. The mass transfer efficiency of PDA-NFsM is extremely high, almost 88.9%, 85.3% and 82.6% of the equilibrium adsorption capacities of CTC, OTC and TC have been achieved in the first 2 min of the adsorption process, which is superior to many other reported materials. The maximum adsorption capacity of PDA-NFsM for TCs at 25 degrees C could reach up to 86.2-161.3 mg/g. Furthermore, the possible adsorption mechanisms were studied by theoretical calculation and spectral analysis. Hydrogen bond was proved to be the main interaction mechanism between the adsorbates and the sorbent. As a kind of monolithic material, the PDA-NFsM can be easily separated from liquid mediums. Moreover, the excellent reusability endows PDA-NFsM with great value in practical application.

Automated summary

The novel polydopamine nanofibers mat (PDA-NFsM) was synthesized by a facile one-step polymerization method, showing high mass transfer efficiency and a maximum adsorption capacity of 86.2-161.3 mg/g for tetracyclines (TCs). The main interaction mechanism between the adsorbates and the sorbent was proved to be hydrogen bond. The monolithic material PDA-NFsM can be easily separated from liquid mediums and has excellent reusability in practical applications.