One-step synthesis of Co-doped UiO-66 nanoparticle with enhanced removal efficiency of tetracycline: Simultaneous adsorption and photocatalysis

In this study, a novel recyclable Co-doped UiO-66 nanoparticle was synthesized by a one-step solvothermal method. A high adsorption capacity of 224.1 mg g(-1) was obtained by the CoUiO-1 nanoparticle, then the adsorbed tetracycline (TC) molecules could be removed more than 94% of initial concentration under simulative sunlight irradiation. The adsorptive ability and photocatalytic performance of CoUiO-1 nanoparticle were about 7.6 and 6.9 times higher than the pristine UiO-66, respectively. The adsorption capacity of CoUiO-1 nanoparticle was sensitive to adsorbent dosage, coexisting ions, solution pH values and initial TC concentrations. Pseudosecond- order and Freundlich models fitted well with the adsorption process. Thermodynamic study indicated the TC adsorption on CoUiO-1 nanoparticle was a spontaneous and exothermic process. TC photodegradation experiment showed that the Co-doped modification expanded light absorption and facilitated charge separation of UiO-66, which was beneficial to enhance photocatalytic performance. The mechanism of TC photodegradation by Co-doped UiO-66 nanoparticle was investigated. Moreover, a plausible degradation pathway for TC was proposed. The high removal efficiencies of CoUiO-1 nanoparticle were obtained towards real samples including tap water, river water and pharmaceutical wastewater. Therefore, the novel Co-doped MOFs photocatalytic adsorbent showed great potential in wastewater treatment.