One step synthesis of a novel Co-doped UiO-66 adsorbent for superior adsorption of organic dyes from wastewater

Metal-organic frameworks (MOFs) is a promising material that can be used in many fields, including environmental remediation. In this work, a novel CoUiO-66 adsorbent was successfully prepared by doping the Co element into the framework of UiO-66 with an in-situ oil bath synthesis. This modification ensured that the materials retain relatively good crystallinity. The Co-doping had a major impact on the particle size and morphology of the original MOFs. The CoUiO-2 exhibited larger surface area and pore size than pristine UiO-66. Accordingly, the maximum adsorption amount of malachite green (MG) on CoUiO-2 (628.93 mg/g) was significantly larger compared with UiO-66 (343.64 mg/g), which was due to more active adsorption sites. In addition, the CoUiO-2 also showed a superior adsorption capacity on rhodamine B (RhB) (1106.22 mg/g). The adsorption process was well described by both the pseudo-second order and Langmuir models, indicating it was dominated by chemisorption and the adsorbent had a homogeneous surface area for adsorption. In conclusion, the CoUiO-2 material was a promising adsorbent for wastewater treatment. This work can provide an important insight into the modification of MOF materials and identify further opportunities to promote the adsorption performance in environmental remediation.