Metal Organic Framework Derivatives Activate Peroxymonosulfate To Degrade Pollutants In Water

At present,researches about MOFs derivatives as catalyst activated peroxymonosulfate（PMS）to produce sulfate radical（SO4·-）on the degradation of pollutants in the water have been done.But studies about the relationships between MOFs templates and the PMS activation effect of their derivatives are rarely reported.In addition,most studies focused on the cobalt oxides which derived from cobalt based Metal-Organic Framework（Co-MOF）.However,there are many kinds of metal ions which make up MOFs.Therefore,there is much room for study.In this study,Co-based MOF with a 2D structure,3D microrod structure and 3D nano-dodecahedral structure was synthesized by the coordination of cobalt ions and different organic ligands.Then,Co₃O₄,which was derived from these Co-based MOFs,was used to activate PMS for RhB degradation.It was found that the morphology and structure of the templates can significantly influence the formation of the nano Co₃O₄ products,which has an indirect effect on the catalytic ability of the resulting Co₃O₄ for PMS to degrade RhB.Among the products,nano-sphere Co₃O₄,which was derived from a template with a 3D nanododecahedral structure（ZIF-67）can effectively activate oxone to degrade RhB.Under neutral conditions,the rate constant of the degradation of RhB（0.1 m M）was 0.0509 min^-1with 50 mg L^-1 catalyst and 1.0 mM PMS based on first-order kinetics.In addition,the influence of a series of parameter factors（pH,the dosage of catalyst and PMS）on the catalyst was also studied.Low cobalt ion dissolution(0.04 mg L^-1 at pH=3,<0.01 mg L^-1 at pH =7)and good recyclability（degradation rate of RhB after 5 cycles: close to 96%,89% at pH=7,pH=3）further proved that the as-prepared Co₃O₄ can be used as a promising catalyst.Moreover,in this paper,a kind of Cu-MOF（HKUST-1）was used as the template to prepare copper oxides at different heat treatment temperatures.The effect of treatment temperatures on the composition and morphology of the products were studied.And the catalytic performance of the copper oxide products was tested through a series of experiments under different conditions of activation of PMS to degrade RhB,OG and AO7 in water.The results of XRD and SEM show that with the increase of heat treatment temperature,the product is gradually transformed from Cu₂O/CuO mixture into pure CuO,and the original skeleton collapse is aggravated.The results of RhB degradation test showed that the activation capacity of the catalyst for PMS increased with the increase of heat treatment temperature.Under neutral pH condition,when the dosage of PMS and CuO-650 was 1.0 mMand 0.2 g L^-1 respectively,the complete degradation of RhB with a concentration of 0.1 mM can be achieved within 90 min.In addition,CuO-650 also has many advantages,such as can be applied to a wide range pH values,the dissolution rate of copper ions was low(1.309 mg L^-1 at pH=3 and 0.987 mg L^-1 at pH=7),great recyclability and stability.These characteristics further proved that CuO-650 can be used as a promising catalyst.Finally,the effects of a series of anions on the degradation of RhB with CuO-650/oxone system were investigated.