Wastewater discharged from the dye production and consumption process has a high chemical oxygen demand, high chroma, and complex structure. In this study, a boat shaped flaky cobalt-basedmetal-organic framework (Co-MOF) was synthesized in aqueous solution by using a green one-step precipitation strategy. This strategy exhibited favorable efficiency for the removal of Congo red (CR). Furthermore, ZIF-67 with a rhombic dodecahedral shape was synthesized in anhydrousmethanol solvent through a one-step precipitation strategy. The effects of the contact time, adsorbent dosage, initial CR concentration, and pH value on the adsorption of CRwere also investigated. Results indicated that the adsorption of CR by Co-MOF and ZIF-67 fittedwellwith the Langmuirmodel and pseudo-second-order kineticmodel. Themaximumadsorption capacities obtained for Co-MOF and ZIF-67 with the Langmuir model were 1019.06 and 1044.58 mg/g at 25 degrees C, respectively. The obtained equilibriumtimewas less than 5min. Moreover, Co-MOF and ZIF-67 had the same removal capacities forCR. The adsorptionmechanismwas attributed to the strong electrostatic and pi-pi stacking interactions of CR with Co-MOF and ZIF-67. Thus, the proposed method is a facile and green method to synthesize Co-MOF for the efficient removal of organic dyes from aqueous solutions. (C) 2020 Elsevier Inc. All rights reserved.