Modification Of Copper-triazolate Metal-organic Framework Via Ligand Doping Towards The Removal Of Water Contaminants

In this paper,by employing the one-pot solid solution approach,functionalized mixed-triazolate MOFs(i.e.,CuMtz-2 and CuMtz-3)were obtained via introducing 3,5-dihydroxymethyl-1H-1,2,4-triazole(3,5-m2-tzH)and 3,5-bis(3-thiophene)-1H-1,2,4-triazole(3,5-3Th2-tzH)into the framework of parent MOF CuTz-1 {[Cu8(3,5-Ph2-tz)6](BF4)2(CH30H)3}(3,5-Ph2-tzH=3,5-diphenyl-1H-1,2,4-triazole),respectively.They were further characterized by a series of techniques such as PXRD,1H-NMR,EA,IR,TGA,and so on.Moreover,the performance of CuMtz-2 and CuMtz-3 towards the removal of water contaminants was investigated.The research of this thesis can be divided into the following three parts:(1)The study on the adsorption of triclosan(TCS)over CuMtz-2 in the different solutions;(2)The study on the adsorption of salazosulfapyridine(SASP)and furosemide(FUR)over CuMtz-2 in the aqueous solution;(3)The study on the photodegradation of CuMtz-3 towards methyl blue(MB)in the aqueous solution.During the study on the adsorption of CuMtz-2 towards the emerging organic pollutants(i.e.,TCS,SASP and FUR),it was found that the adsorption rate constants of CuMtz-2a were about 1.23-9.2 times that of the parent MOF CuTz-1.The adsorption capacity has increased by 0.28-1.82 times.The adsorption of TCS,SASP and FUR over MOFs(CuTz-1 and doped MOFs)fitted the Langmuir model quite well.Significantly,CuMtz-2b,in which the highest doping amount of 3,5-Hm2-tzH(22%)was obtained,exhibited the highest adsorption capacity towards the three emerging organic pollutants.Moreover,the increase on the adsorption capacity of TCS over CuMtz-2b was observed with the decreased temperature;on the contrary,the effect of temperature during the adsorption of SASP and FUR followed the other tendency.The proposed mechanism suggested that the hydrogen bonding played a vital role during the adsorption process,with the assitance of anion exchange between BF4-and anioic pollutants.The increase on the adsorption capacity over CuMtz-2b can be attributed to the introduction of hydroxy-containing ligand(3,5-Hm2-tzH),which is able to form hydrogen bond with the pollutants and therefore facilitate the adsorption process.In addition,after the adsorpiton of TCS,the used CuMtz-2b can be regenerated and used for another three cycles while maintaining the adsorption rate up to 96%and keeping its stability.The photodegradation of MB by MOFs(CuTz-1,CuMtz-3b)showed that the degradation behavior fitted well with the pseudo-first-order kinetic model.The degradation rate of MB using CuMtz-3b as the catalyst was 0.034 min-1,which was 1.42 times higher than that using CuTz-1.More importantly,such degradation rate CuMtz-3b has shown is better than most of the reported photocatalysts towards the photodegradation of MB.It was found that the contribution order of active species to the whole degradation reaction is as follows:·O2->e->h+>·OH.In addition,CuMtz-3b can be used for four cycles of photodegradation process and kept the initial degradation rate of MB while maintaining the stability.Over all,in this work,by introducing functional ligands into the parent MOF CuTz-1,the adsorption and photocatalytic performance of the functionalized MOFs(CuMtz-2 and CuMtz-3)are greatly enhanced compared with the pristine CuTz-1.Moreover,the good reusability and stability suggest those two kinds of functionalized MOFs are potential materials towards the removal of pollutants in water.