| Recent years,metal organic frameworks(MOFs)have shown broad application prospects as photocatalysts and/or adsorbents towards the removal of organic pollutants in water.In this paper,employing the solid solution approach,copper mixed-triazolate MOFs(CuMtz-1 and CuMtz-2)were successfully obtained,where 3,5-dithiophene-1H-1,2,4-triazole(3,5-Th2-tzH)and 1,2,4-triazole were incorporated into the framework of the parent MOF CuTz-1?[Cu8(3,5-Ph2-tz)6](BF4)2(CH3OH)3?(3,5-Ph2-tzH=3,5-diphenyl-1H-1,2,4-triazole),and the photocatalytic degradation performance of CuMtz-1 and the adsorption performance of CuMtz-2 were studied respectively.Firstly,study on the photocatalytic performance of CuMtz-1:it was found that the rate constant of the photodegradation by the mixed-ligand MOF CuMtz-lb[Cu8(3,5-Ph2-tz)4.9(3,5-Th2-tz)1.1](BF4)2(CH3OH)3 is ca.2-3 times that of the parent MOF CuTz-1,and the removal rate of organic pollutants increased ca.30%-40%.And it was found that the removal rate of organic pollutants was higher under acidic conditions and ultraviolet light irradiation via effect investigation of pH and light source on photodegradation.COD value of the reaction solution decreased with the increase of reaction time.Moreover,UPLC-MS of the reaction solution together with COD analysis showed that CuMtz-lb is able to degrade organic pollutants into small molecules under light irradiation.Investigation on the mechanism revealed that it is the·O2-radicals generated by the irradiation on the MOFs that play an important role in the photodegradation of organic pollutants.The degradation efficiency of organic pollutants over CuMtz-lb can be retained after four cycles of process while maintaining the stability and morphology of the photocatalysts,which indicated that CuMtz-lb had good reusability and stability.Secondly,study on the adsorption performance of CuMtz-2:Compared with the parent MOF CuTz-1,the mixed-ligand MOF CuMtz-2b[Cu8(3,5-Ph2-tz)4.9(tz)1.1](BF4)2.8(CH3OH)demonstrated a faster reaction rate constant,higher affinity and larger adsorption capacity for SSZ and DCF,and its reaction rate constant is comparable with most of the reported MOF adsorbents.Based on the study of the effect of pH and temperature on adsorption,it was found that the removal rate of SSZ and DCF were higher under acidic conditions.Moreover,the adsorption capacity of CuMtz-2b for DCF increased with the elevated reaction temperature,which indicated that the adsorption of DCF with CuMtz-2b is an endothermic process.Investigation on the adsorption mechanism revealed that the adsorption of DCF over CuMtz-2b was mainly attributed to anion exchange and electrostatic attraction.Cyclic adsorption experiments showed that CuMtz-2b has good stability and reusability. |
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