Efficient Removal Of Phenols From Water By Porous Organic Frameworks

Water is essential to life,agriculture,industry and the natural world.An article by the World Health Organization?WHO?noted that only one quarter of the world's population had access to safe and hygienic drinking water,the problem that was more acute in developing countries.In order to overcome this global problem,we must pay attention to the treatment of water environment and realize the recovery and reuse of wastewater.In daily life,phenolic compounds?phenol and its derivatives?are widely used chemicals,which are abundant in wastewater and pose a serious threat to public health and aquatic ecosystems.They have strong odor,poor biodegradability,toxic and carcinogenic.Therefore,the removal of phenols from aqueous environments is critical.At present,although there have been many studies on removal of phenolic compounds in water environment,it is still necessary to develop efficient,simple and rapid methods to remove phenolic compounds from water environment.In this paper,three porous organic frameworks were synthesized,and their adsorption to remove phenol and several phenol derivatives in water were studied,the removal effect is ideal.The contents of the study are as follows:1. MIL-101?Cr?-NH₂were synthesized from Cr?NO₃?₃·9H₂O and2-aminoterephthalic acid in alkaline environment by hydrothermal method.The materials were characterized by x-ray diffraction analysis,Fourier transform infrared test,electron microscopic test,N₂adsorption-desorption isotherms experiment and so on.Bisphenol A and 2,4-dichlorophenol were adsorbed from water by using the obtained materials.By optimizing the adsorption time,solution p H and temperature,the optimum adsorption conditions were obtained.At optimal adsorption conditions,the maximum adsorption amounts of bisphenol A and 2,4-dichlorophenol were 118.3mg g^-1and 78.30 mg g^-1,respectively.2. The covalent organic frameworks COF-Tp Pa-1 were synthesized by the schiff base reaction between 1,3,5-Triformylphoroglucinol?Tp?and p-phenylenediamine?Pa-1?using solvothermal method,and were used to adsorb bisphenol A and2,4-dichlorophenol in water.The p H and salt concentrations in the process of adsorption were optimized,and adsorption kinetics,adsorption thermodynamics and repeatability were investigated.The real samples were also analyzed by COF-Tp Pa-1.3. Covalent organic framework COF-V were synthesized using 2,5-diethenyl-1,4-benzenedicarboxaldehyde and 1,3,5-tris?4-aminophenyl?benzene as reaction monomers,and the solvent types,solvent dosage,time and other reaction conditions were optimized.COF-V was applied to the adsorption of bisphenol A in water,and it has an ideal adsorption effect on bisphenol A.To explore the adsorption mechanism,two other structurally similar adsorbent COF and COF-V-MPBA were synthesized for the adsorption of bisphenol A.The best adsorbent COF-V was further applied to the removal of phenol,2-chlorophenol,2,4-dichlorophenol,2,4,6-trichlorophenol,bisphenol A and tetrabromobisphenol A.The maximum adsorption capacity of phenol,2-chlorophenol,2,4-dichlorophenol,2,4,6-trichlorophenol,tetrabromobisphenol A and bisphenol A were 40.32 mg g^-1,84.94 mg g^-1,273.8 mg g^-1,551.6 mg g^-1,338.9 mg g^-1and 540.9 mg g^-1,respectively.For the standard recovery experiment of bisphenol A in lake water,the removal rate were between 87.5%and 100.8%,and the recoveries were from 97.2%to 103.1%.