Adsorption and pH-Responsive Release of Tinidazole on Metal–Organic Framework CAU-1

Herein, a porous hydrostable metal–organic framework (MOF), CAU-1, was systematically studied for its adsorption performance of tinidazole (TNZ). Owing to the abundant −OH and −NH2 groups as well as the strong positively charged surface of the framework, the H-bond interaction and electrostatic interaction can play important roles in the adsorption process of TNZ. As a result, CAU-1 exhibits an excellent saturated adsorption capacity of TNZ (∼450 mg·g–1), superior to all of the previous reported porous adsorbents including other common MOFs. Meanwhile, the loaded TNZ molecules in CAU-1 can be released under simulated physiological conditions and the cumulative release amount can be controlled via the pH value of solution. This work demonstrates that such an MOF may be promising in TNZ removal, and rational selection of organic functional groups is an efficient strategy to design high-capacity adsorbents for the removal of antibiotics. Additionally, further study indicates that CAU-1 can serve as a pH-responsive carrier to control TNZ release.